Title of Invention	DEVICE FOR DRYING COMPRESSED GAS
Abstract	Device for drying a compressed gas in a non-dissipative manner, which mainly consists of a compressed gas supply (2), at least two pressure vessels (31, 32) with an input (33, 34) and an output (35, 36) and take-off point (26), whereby the device (1) is additionally provided with a first distribution device (3) and a second distribution device (13) which is provided with one or several coolers (30) and whereby the device (1) can be controlled by means of nine or ten cut-off valves (7-12, 21,22, 29, 38 and 40).

Title of Invention

DEVICE FOR DRYING COMPRESSED GAS

Abstract

Device for drying a compressed gas in a non-dissipative manner, which mainly consists of a compressed gas supply (2), at least two pressure vessels (31, 32) with an input (33, 34) and an output (35, 36) and take-off point (26), whereby the device (1) is additionally provided with a first distribution device (3) and a second distribution device (13) which is provided with one or several coolers (30) and whereby the device (1) can be controlled by means of nine or ten cut-off valves (7-12, 21,22, 29, 38 and 40).

Full Text	J^^^^^ DESCPAMD 8E20Q6Q001 -4- Device for drying compressed gas. The present invention concerns a device for drying a 5 compressed gas. In particular, the invention concerns a device for drying compressed gas in a non-dissipative manner, in other words a device whereby the heat of the compression, present in 10 the compressed gas, is used as a whole or partly to regenerate the desiccant, and whereby the entire supplied gas flow flows integrally through the device, without any part of this gas being blown off in the atmosphere or being fed back to the output of the device, which results 15 in that such a device has a better efficiency than certain existing devices. In particular, the invention concerns a device for drying a compressed gas in a non-dissipative manner, which mainly 20 consists of a supply of compressed gas, for example in the shape of a compressed air compressor, at least two pressure vessels with an input and an output and a take- off point for compressed gas consumers. 25 Such devices are already known, for example from U.S. patent No. 6.3.71.377, whereby the above-mentioned pressure vessels are filled with a dessicant and whereby the gas to be dried is sent through a first regenerating ed at the EPO on Mar 01,2007 11:58:13. Pc AMENDED SHEET 01/03/2007 WO 2007/033440 PCT/BE2006/000100 pressure vessel so as to absorb moisture from the desiccant, by making use of the heat of said compressed gas, and to thus regenerate this desiccant, and whereby this gas is subsequently cooled by means of a cooler to 5 be then guided through a second drying pressure vessel where this cooled gas is dried by the desiccant. As soon as the desiccant in the drying pressure vessel is saturated, the flow-through sequence of the pressure vessels is reversed, such that the first pressure vessel 10 becomes a drying vessel, whereas the second pressure vessel is turned into a regenerating pressure vessel. Thus, thanks to the alternating use of the above- mentioned pressure vessels as a drying and regenerating pressure vessel, one pressure vessel will always be 15 regenerated by the compressed gas, whereas the other pressure vessel makes sure that this compressed gas is subsequently dried. The known devices for drying a compressed gas in a non- 20 dissipative manner are disadvantageous in that they are provided with a large number of pipes and valves for reversing the pressure vessels as regenerating and drying pressure vessels, and in that they are very large and expensive and have a complex, non-modular design, such 25 that a large number of variants need to be supported, which increases the development, production and maintenance costs. In order to make the existing devices less complex, use d* 08/08/2007 DEBOPAMD OE20060001 ■•3- is sometimes made of three-way and/or four-way valves, which are much more expensive and less reliable than conventional two-way valves, such that the operational reliability of the installation as a whole is strongly 5 reduced. An additional disadvantage for devices with a larger Capacity for drying compressed gas is that it is often impossible, or at least economically inefficient to find 10 3-way or 4-way valves which meet the demands as far as required temperature, pressure and flow are concerned. US 6.375.722 and WO 03035220 both describe a device for drying gas in a dissipative manner, whereby part of the 15 gas is blown off in the atmosphere, and whereby said device comprises at least fourteen valves. The present invention aims to offer a device for drying a compressed gas in a non-dissipative manner which does not 20 have the above-mentioned and other disadvantages and which can be applied to different types of adsorption drying devices in a simple and cheap manner. To this end, the present invention concerns a device of 25 the above-mentioned type for drying a compressed gas in a non-dissipative manner, whereby this device is is additionally provided with a first distribution device onto which said compressed gas supply and the take-off point are connected and which is also connected to each of 30 the respective outputs of the above-mentioned pressure ed at the EPO on Mar 01. 2007 11 -fift-i-* >- A»/. 0)008/' 7d: 0S/08/20Q7 DESCPAMD BE20060001 - 3a - vessels, and whereby the cibove-mentioned first and second distribution devices are connected to each other, said device being characterised in that it is provided with nine or ten cut-off valves; in that said first 5 distribution device comprises three parallel connected pipes in which are each time provided two cut-off valves and onto which is each time connected, between two cut-off valves, a branch, namely a first pipe with a first branch which provides a connection to the second distribution 10 device, a second pipe with a second branch which is connected to the above-mentioned take-off point for a compressed gas consumer; and a third pipe with a third branch as a connection to the compressed gas supply and a fourth branch which is connected to the second 15 distribution device via a cut-off valve and in that said second distribution device comprises three parallel connected pipes, a first pipe and a second pipe respectively in which are provided two non-return valves with an opposite flow direction and a third pipe with two 20 cut-off valves in it, whereby the first pipe, the second pipe respectively, are each connected between the two non- return valves, to said fourth branch and the first branch of the first distribution device respectively, and whereby the first and the third pipe of the second distribution 25 device are mutually connected via a cooler between the valves. By cut-off valves are meant valves which can be controlled manually or in an automated manner, in other words which 30 can be opened and closed; Non-return valves which cannot — 4 ed at the EPO on Mar 01.2007 11:58:13. ft AMENDED SHEET HIPN1 „..„«._ 01009/1 S: 08/08/2007 DESCPAMD BE20060001 be controlled as such are considered consequently not regarded as cut-off valves as meant here. A really major advantage of such a device according to the 5 present invention is that it only has to be provided with a relatively limited number of valves compared to the existing devices for drying a compressed gas in a non- dissipative manner, as a result of which the device is cheaper and requires less maintenance costs. 10 If the above-mentioned valves are made in the form of automatically controlled valves, use can be made in this specific construction of a relatively simple control system with a limited number of inputs and outputs, and 15 the control program is simplified as well in comparison with the known devices. In a preferred embodiment of a device according to the invention, the above-mentioned first and second 20 distribution devices are each built symmetrically and/or modularly. By a symmetrical construction of the distribution devices is meant a functional symmetry in this case, and not so 25 much a strictly geometric symmetry. This . - £f rtW ->♦ +u- cnA WO 2007/033440 PCT/BE2006/000100 5 implies that the distribution devices can be made asymmetrical in shape, but that the device can be represented by means of a symmetrical functional diagram. 5 A major advantage of such a device according to the invention is that, thanks to the symmetrical construction, it contains a large number of common parts, such as for example pipes and pressure vessels, which can consequently be produced in larger numbers and thus 10 in a cheaper manner. Another advantage of a device according to the invention is that, thanks to the symmetrical construction, the above-mentioned distribution devices can be mounted one above the other, such that the length 15 of the connecting lines between both distribution devices is reduced to a minimum, the device is reduced in size, and costs are saved. Another advantage of a device according to the invention is that, thanks to the combination of the modular 20 construction and the symmetrical arrangement of the distribution devices, one and the same distribution device can be combined with pressure vessels having different diameters. Since the diameter of the pressure vessels, as opposed to the diameter of the pipes in 25 the distribution device, strongly depends on the flow rate to be dried, there are usually many more variants of the pressure vessels than there are variants of distribution devices. WO 2007/033440 PCT/BE2006/000100 6 Since, according to the invention, variants of distribution devices and pressure vessels are independently interchangeable, less different parts will need to be kept in stock and production costs can be 5 saved. In order to better explain the characteristics of the present invention, the following preferred embodiments of a device according to the invention for drying a 10 compressed gas are given as an example only without being limitative in any way, with reference to the accompanying drawings, in which: figure 1 schematically represents a device according to the invention; 15 figures 2 to 5 illustrate the working of a device according to figure 1; figure 6 represents a practical embodiment of the device according to figure 1; figures 7 and 8 represent a view according to arrows F7 and 20 F8 respectively in figure 6; figures 9, 14, 19 and 24 represent variants of a device according to figure 1; figures 10 to 13, 15 to 18, 20 to 23 and 25 to 28 represent the working of a device according to figures 25 9, 14, 19 and 24 respectively. Figure 1 represents a device 1 according to the invention for drying a compressed gas in a non-dissipative manner which is provided with a compressed gas supply 2, which in this -case is formed of a compressor and which is connected 30 to a first distribution device 3. WO 2007/033440 PCT/BE2006/000100 7 The above-mentioned first distribution device 3 is in this case formed of three parallel pipes which are connected to each other, a first pipe 4, a second pipe 5 and a third pipe 6 respectively, in which are each time provided two valves 7- 5 8f 11-12 and 9-10 which can be cut off, which in this case, but not necessarily, are made in the shape of controlled valves which are connected to a control system which is not represented in the figures. 10 Further, the device 1 comprises a second distribution device 13 which in this case has practically the same dimensions and geometry as the above-mentioned first distribution device 3 and which also mainly consists of three parallel pipes 14, IS and 16 which are connected 15 to each other, a first pipe 14 and a second pipe 15 respectively in which are each time provided two non- return valves 17-18, 19-20 respectively with an opposite flow direction, and a third pipe 16 with two valves 21 and 22 in it which can be cut off and which 20 in this case, but not necessarily, are made in the form of controlled valves as well which are connected to the above-mentioned control system. In the given example, the above-mentioned non-return 25 valves 17 and 18 in the first pipe 14 of the second distribution device 13 are positioned such that they allow for a flow in the direction of one non-return valve to the other non-return valve in the pipe 14 concerned, and the above-mentioned non-return valves 19 and 20 in the 30 second pipe 15 of the second distribution device 13 are WO 2007/033440 PCT/BE2006/000100 8 positioned such that they allow for a flow in the direction away from the other non-return valve in the pipe 15 concerned. 5 It should be noted that the functional diagram in figure 1 of the above-mentioned first and second distribution device 3 and 13 is built up symmetrically. This symmetry can also be used in a practical embodiment, such as represented for example for the distribution devices 3 and 10 13 in figures 6 to 8. Between the valves 7 and 8 which can be cut off from the pipe 4 is connected a first branch 23 which provides a connection to the second distribution device 13 and which is connected in particular via a cooler 24 to the 15 pipe 15/ between the non-return valves 19 and 20. In the pipe 5, between the valves 11 and 12 which can be cut off, is connected a second branch 25 which is connected to a take-off point 26 for a compressed gas 20 consumer. Between the valves 9 and 10 which can be cut off from the pipe 6 is provided a third branch 27 as a connection to the above-mentioned compressed gas supply 2 and a fourth branch 28 which is connected to the second distribution 25 device 13 via a valve 29 which can be cut off, in particular between the non-return valves 17 and 18 in the pipe 14. The pipes 14 and 16 are mutually connected between the WO 2007/033440 PCT/BE2006/000100 9 above-mentioned valves 17-18 and 21-22 via a cooler 30. Further, the device 1 for drying a compressed gas in a non-dissipative manner is also provided with two pressure 5 vessels 31 and 32 which are filled with a desiccant, for example in the form of silica gel, and which are both provided with an input 33, 34 respectively and an output 35, 36 respectively. 10 It is clear that instead of silica gel as a desiccant, also other desiccants can be used. The above-mentioned first distribution device 3 is connected to the outputs 35 and 36 of the pressure 15 vessels 31 and 32 with the respective parallel connections between the pipes 4, 5 and 6, whereas the second distribution device 13 is connected to the inputs 33 and 34 of these pressure vessels 31 and 32 with the respective parallel connections between the pipes 14, 15 20 and 16. According to the invention, the device 1 in this case has only nine valves 7 to 12, 21, 22 and 29 which can be cut off, which is less than with the known devices for drying compressed gas in a non-dissipative manner, so 25 that, partly thanks to the symmetry, a simpler layout is obtained which is moreover less liable to wear and consequently requires less maintenance. The working of a device 1 according to the invention for drying a compressed gas in a non-dissipative manner WO 2007/033440 PCT/BE2006/000100 10 is very simple and is illustrated by means of figures 2 to 5, whereby cut-off valves are represented in black when they are closed in these figures, whereas valves in their open position are represented in white and the 5 flow of the gas is represented in bold. In a first phase, which is represented in figure 2, the pressure vessel 31 is used to regenerate the desiccant which is present in this pressure vessel 31, and the pressure vessel 32 is used for drying gas coming from the 10 supply 2. To this end, the hot, compressed gas coming from the supply 2 is guided, via the open valve 9, through the first pressure vessel 31. 15 Moisture which is present in the desiccant in this first pressure vessel 31 is absorbed by the hot, compressed gas, such that the desiccant is regenerated in this first pressure vessel 31. 20 Next, the gas flow goes to the cooler 30 via the non- return valve 17, where it is cooled, and part of the moisture situated in the gas flow will condense to be then guided via the valve 22 through the second pressure vessel 32, where the gas is dried by the desiccant. 25 The output 36 of the second pressure vessel 32 is at that time connected via the valve 12 to the take- off point 26 onto which one or several dried compressed gas consumers are connected. WO 2007/033440 PCT/BE2006/000100 11 It is clear that the output coming from the supply 2 flows entirely and without any losses through both pressure vessels 25 to the take-off point 26. During a second phase, which is represented in figure 3, 5 and which occurs at the end of the regeneration cycle of the desiccant in the regenerating pressure vessel 31, the entire output of compressed gas is successively guided via the valve 29 through the cooler 30 and via the valve 21 through the first pressure vessel 31, as a result of 10 which this first, regenerating pressure vessel 31 is cooled. Next, the gas flows via the valve 7 and the branch 23 through the cooler 24 and the non-return valve 20 to the second pressure vessel 32 where this gas is dried by the 15 desiccant, after which it flows via the valve 12 and the branch 25 to the take-off point 26 for compressed gas consumers. In a third, subsequent phase, when the desiccant in 20 the drying pressure vessel 32 is almost saturated and/or the desiccant in the regenerated pressure vessel 31 is practically cooled, the compressed gas, as represented in figure 4, is divided for a short time span via the cooler 30 and via the valves 21 and 22 over both pressure 25 vessels 31 and 32. The regenerated pressure vessel 31 is hereby cooled somewhat further, and the almost saturated pressure vessel 32 is somewhat relieved. An advantage of cooling the desiccant in the regenerated WO 2007/033440 PCT/BE2006/000100 12 pressure vessel 31 at the end of the regeneration cycle is that, at the time the pressure vessels 31 and 32 are changed over, whereby the regenerated pressure vessel 31 becomes a drying pressure vessel and vice 5 versa, temperature and dew point peaks of the compressed gas at the take-off point 26 are avoided. In a fourth and final phase, represented in figure 5, the entire output of the compressed gas is carried via the valve 29, the cooler 30 and the valve 22 through the 10 practically saturated second pressure vessel 32, after which it is guided to the above-mentioned take-off point 26. After this final phase there is a return to the first phase, but the pressure vessels 31 and 32 are hereby 15 changed over and the first pressure vessel 31 then becomes the drying pressure vessel, whereas the second pressure vessel 32 will be regenerated, etc. Since it is possible to dry in a non-dissipative manner with a device 1 according to the invention (save for a 20 pressure drop of the gas between the inlet and the outlet), energy can be saved in comparison with devices whereby a part of the compressed gas is fed back or is blown off in the atmosphere. In an embodiment of a device 1 according to the 25 invention which is not represented in th-e figures, heating elements can be provided, either in the pressure vessels 31 and 32, or outside these pressure WO 2007/033440 PCT/BE2006/000100 13 vessels 31 and 32, which heating elements are designed to better regenerate the desiccant, and to thus further reduce the dew point of the gas at the outlet of the device 1. 5 Figures 6 to 8 represent a practical embodiment of a device according to figure 1, whereby the first and second distribution device, 3 and 13 respectively, are made symmetrical by means of tubular constructions which are identical in shape and which are provided 10 concentrically on top of each other. In the given example, the above-mentioned tubular constructions are made according to standard dimensions, such that they can be combined with pressure vessels 31 15 and 32 having different volumes and for devices 1 having different capacities. Thus, the arrangement of the pressure vessels and tubular construction is modular, as a result of which the number of variants for the production is restricted and costs are saved. 20 In this case, the above-mentioned branches and connections can be realised in a simple manner by means of short pipes or lines provided between the tubular constructions situated on top of each other. Figure 9 r-epresents another embodiment of a device 1 25 according to the invention, whereby no cooler is provided in the above-mentioned first branch 23 of the first distribution device 3 in this case. WO 2007/033440 PCT/BE2006/000100 14 This will reduce the cost of the device even further, whereas it is nevertheless possible to obtain a good output with the device 1. 5 The working of this variant is practically analogous to that of the preceding embodiment. The first, third and fourth phases as represented in figures 10, 12 and 13 respectively, are identical to the first, third and fourth phases of the preceding 10 embodiment, as represented in figures 2, 4 and 5 respectively. The second phase, which is represented in figure 11, is somewhat different in this embodiment from the one described above. 15 During this second phase, the entire output of gas to be dried is directed via the valve 29 through the cooler 30 in this case, after which this gas flows via the valve 22 to the input 34 of the second, drying pressure vessel 32 so as to be dried. 20 Next, the dried compressed gas flows via the valve 8 and through the first branch 23 of the first distribution device 3 to the pipe 15, where this gas flows via the non-return valve 19 to the regenerating pressure vessel 31 so as to then be carried via the branch 25 to the 25 take-off point 26. Since the compressed gas is cooled and dried first, WO 2007/033440 PCT/BE2006/000100 15 before flowing through the regenerating pressure vessel 31, this gas will cool said regenerating pressure vessel 31. Figure 14 represents yet another embodiment of a device 5 1 according to the invention for drying a compressed gas in a non-dissipative manner, whereby a connecting line 37 is provided between the valves 7 and 8 in the pipe 4 and between the valves 21 and 22 in the pipe 16, in which is provided a valve 38 which can be cut off. 10 In this case, the device 1 according to the invention is controlled by means of ten cut-off valves, which is considerably less than with known devices which make it possible to go through the same phases and to dry in a non-dissipative manner. 15 The working of such an embodiment according to figure 14 is practically analogous to that of the first embodiment and it is represented in figures 15 to 18. In a first phase, which is represented in figure 15, the hot compressed gas is first guided via the valve 9 through 20 the regenerating pressure vessel 31, after which the damp gas is guided via the non-return valve 17, the cooler 30 and the valve 38 through the branch 23 and the cooler 24 to subsequently flow through the non-return valve 20 to the drying pressure vessel 32 where it is dried. 25 The dried -compressed gas is finally carried via the valve 12 and the branch 25 to the above-mentioned take-off point 26 for WO 2007/033440 PCT/BE2006/000100 16 compressed gas consumers. Consequently, the coolers 30 and 24 are connected in series in this case, as a result of which the cooling capacity is increased and as a result of which the gas can be dried more 5 efficiently. This results in a lower dew point of the compressed gas at the take-off point of the dryer. During the second phase, which is represented in figure 16, the gas flows through the device 1 in an identical manner as during the second phase of the device, as is represented in 10 figure 3, whereby the regenerating pressure vessel 31 is cooled. During the third and the fourth phase, which are represented in figures 17 and 18 respectively, the above-mentioned coolers 30 and 24 are each time connected in series by 15 opening the valve 38 and closing the valve 22. In the third phase, after flowing through the coolers 30 and 24, the gas is split up via the non-return valves 19 and 20 in the pipe 15 to the regenerating pressure vessel 31 on the one hand and the drying pressure vessel 32 on the 20 other hand. Next, these split gas flows come together again via the valves 11 and 12 in the branch 25 so as to be guided to the take-off point 26. During the fourth phase, the entire compressed gas 25 flow, cooled by the coolers 30 and 24, is sent through WO 2007/033440 PCT/BE2006/000100 17 the drying pressure vessel 32, after which it flows via the branch 25 to the take-off point 26. By analogy with the preceding embodiments, the drying pressure vessel 31 is afterwards changed over to the 5 regenerating pressure vessel 32. It should be noted that, in this embodiment of the device 1, both available coolers 30 and 24 can be used in any phase of the drying process, and thus, in every phase, the compressed gas is maximally cooled before flowing into 10 the drying pressure vessel 31, which results in a minimal dew point of the gas at the take-off point 26. Figure 19 represents another variant of a device 1 according to figure 1 whereby, in this case, a 15 connecting line 39 is provided between the valves 7 and 8 which can be cut off in the pipe 4 and between the non-return valves 17 and 18 in the pipe 14, in which is provided a valve 40 which can be cut off. The working of such a variant is analogous to that of the 20 preceding embodiment, whereby in this case however, in the first, third and fourth phase, the coolers 30 and 24 are connected in parallel, as a result of which the cooling capacity will be considerably higher than with a single cooler, and the gas can be dried better. 25 Moreover, by connecting the coolers 30 and 24 in parallel, the pressure drop over these coolers 30 and 24 will be lower than when these coolers 30 and 24 are connected in series. WO 2007/033440 PCT/BE2006/000100 18 The coolers 30 and 24 are connected in series, as is represented in figures 20, 22 and 23, by opening the valves 40 and 22 which can be cut off. Figure 24 represents yet another embodiment of a device 5 according to figure 1, whereby three pressure vessels 41, 42 and 4 3 are provided which are connected to a first distribution device 44 with their outputs and to a second distribution device 45 with their inputs. The above-mentioned first distribution device 44 in this case 10 consists of three main pipes, namely a first 30 main pipe 46 onto which are connected three branches 47 to 49; a second main pipe 50 with branches 51 to 53; and a third main pipe 54 with branches 55 to 57. Each of the above-mentioned branches 47 to 49, 51 to 53 15 and 55 to 57 is connected to the output of a respective pressure vessel 41, 42 and 43. In the branches 4 7 to 4 9 and 51 to 53 is each time provided a cut-off valve, whereas in each of the 20 branches 55 to 57 is provided a non-return valve which is positioned such that it allows for a flow to the respective pressure vessel 41, 42, 43 with which the branch 55 to 57 concerned is connected. 25 The main pipes 46 and 54 are connected to each other by means of a bypass 58, and the above-mentioned supply 2 for compressed gas is directly connected to the main pipe 50. WO 2007/033440 PCT/BE2006/000100 19 The second distribution device 45 is built in practically the same manner as the first distribution device 44, and it is also provided with three main pipes, a first main pipe 59 with three branches 60 to 5 62; a second main pipe 63 with branches 64 to 66; and a third main pipe 61 with branches 68 to 70 respectively. Each of the above-mentioned branches 60 to 62, 64 to 66 and 68 tot 70 is connected to the input of a respective 10 pressure vessel 41, 42 and 43. In the branches 60 to 62 and 64 to 66 is each time provided a cut-off valve, whereas in each of the branches 68 to 70 is provided a non-return valve which is positioned such that it allows for a flow from the 15 respective pressure vessels 41, 42, 43 with which the branches 68 to 70 concerned are connected. The main pipes 63 and 67 of the second distribution device 45 are connected to each other via a cooler 71. The above-mentioned main pipe 54 is connected to the 20 main pipe 59 and to the take-off point 26 for compressed gas consumers by means of a first connecting line 72 having a valve 73 which can be cut off provided in it. The above-mentioned main pipe 50 is connected to the main pipe 67 by means of a second connecting line 74, in 25 which is provided a valve 75 which can be cut off. The working of a device 1 according to figure 24 is WO 2007/033440 PCT/BE2006/000100 20 represented step by step in figures 25 to 28. In a first phase, the first pressure vessel 41 is regenerated, whereas the second and third pressure vessels 42 and 43 both form drying pressure vessels. 5 The hot compressed gas is in this first phase directed via the branch 51 through the pressure vessel 41, where the hot gas absorbs moisture from the desiccant, as a result of which this pressure vessel 41 is regenerated. 10 Next, the damp, compressed gas flows via a non-return valve in the branch 68 to the cooler 71, after which the cooled gas flows through the valves in the branches 65 and 66 to the pressure vessels 42 and 4 3 to be dried. 15 The dried compressed gas is then directed through the valves in the branches 48 and 4 9 and via the main pipe 46 to the bypass 58 and afterwards, via the connecting line 72, to the take-off point 26. In the second phase, which is represented in figure 26, the hot 20 compressed gas, coming from the supply 2, is first directed via the connecting line 74 and the main pipe 67 through the cooler 71 to subsequently flow via the branches 65 and 66 to the pressure vessels 42 and 43 so as to be dried there. The dried compressed gas is then directed via the branches 48 25 and 49 and via the bypass 58 through the non-return valve in WO 2007/033440 PCT/BE2006/000100 21 the branch 55 into the first pressure vessel 41 which is cooled by the gas. Finally, the gas flow is directed via the branch 60 to the take-off point 26. 5 In the third phase, which is represented in figure 27, the hot compressed gas is first directed via the connecting line 74 and the main pipe 67 through the cooler 71 to be subsequently split and be directed via each of the branches 64 to 66 to the respective pressure vessels 41 10 to 43. Next, the split gas flows are directed via the branches 47 to 49 to flow together again in the main pipe 46 and to be carried via the bypass 58 and the connecting line 72 to the take-off point 26. 15 The first pressure vessel 41 is cooled further in this third phase, since the supplied gas is first directed through the cooler 71. During the fourth and final phase which is represented in 20 figure 28, the entire output of compressed gas is directed via the connecting line 74 and the main pipe 67 through the cooler 71. Next, the gas flows through the cut-off valves in the 25 branches 65 and 66 to the pressure vessels 42 and 4 3, to then flow via the branches 48 and 4 9 and the bypass 58 to the connecting line 72 and the take-off point 26. WO 2007/033440 PCTYBE2006/000100 22 Such an embodiment of device 1 for drying a compressed gas in a non-dissipative manner with three pressure vessels 41, 42 and 43 has more cut-off valves 20 than the above-described embodiments, but the layout appears to be 5 considerably simpler than the existing ones with three pressure vessels, such that this device 1 can be realised in a relatively cheap manner. It is clear that in all the embodiments of a device 1 according to the invention, the cut-off valves may be 10 electrically controllable, but they can also be controlled in other ways, such as for example in a pneumatic manner or the like, or they can even be manually controllable. The present invention is by no means limited to the 15 embodiments described as an example and represented in the accompanying drawings; on the contrary, such a device 1 according to the invention for drying a compressed gas in a non-dissipative manner can be made in all sorts of shapes and dimensions while still remaining within the 20 scope of the invention. LflOlO/i BE20G60001 :^^^^^^ CLMSPAMD Claims. 1.- Device for drying a compressed gas in a non- 5 dissipative manner, which mainly consists of a compressed gas supply (2), two pressure vessels (31,32) with an input (33,34) and an output (35,36), and a take-off point (26) for compressed gas consumers, whereby the above-mentioned device (1) is additionally provided with a first 10 distribution device (3) onto which said compressed gas supply (2) and the take-off point (26) are connected and which is also connected to each of the respective outputs (35 and 36) of the above-mentioned pressure vessels (31 and 32), and whereby the above-mentioned first and second 15 distribution devices (3 and 13) are connected to each other, characterised in that the device (1) is provided with nine or ten cut-off valves (7-12, 21, 22, 29, 38 and 40); in that said first distribution device (3) comprises three parallel connected pipes (4, 5 and 6) in which are 20 each time provided two cut-off valves (7,8; 9,10; 11,12) and onto which is each time connected, between two cut-off valves (7,8; 9,10; 11,12), a branch, namely a first pipe (4) with a first branch (23) which provides a connection to the second distribution device (13), a second pipe (5) 25 with a second branch (25) which is connected to the above- mentioned take-off point (26) for a compressed gas consumer; and a third pipe (6) with a third branch (27) as a connection to the compressed gas supply (2) and a fourth branch (28) which is connected to the second distribution 30 device (13) via a cut-off valve (29) and in that said ived at the EPOon Mar 01, 2007 11:58:13. P •say -.: ..:....."7. .r.~: T ~" -"' "A T-)' J ZJJ(JLO BE20060001 .^^^^^ CLMSPAMD -if - second distribution device (13) comprises three parallel connected pipes {14, 15 and 16), a first pipe (14) and a second pipe (15) respectively in which are provided two non-return valves (17,10 and 19,20) with an opposite flow 5 direction and a third pipe (16) with two cut-off valves (21 and 22) in it, whereby the first pipe (14), the second pipe (15) respectively, are each connected between the two non-return valves (17,18 and 19,20), to said fourth branch (28) and the first branch (23) of the first distribution 10 device (3) respectively, and whereby the first and the third pipe (14 and 16) of the second distribution device (13) are mutually connected via a cooler (30) between the valves (17,18 and 21,22). 15 2.- Device according to claim 1, characterised in that the above-mentioned first and second distribution devices (3 and 13) are each built symmetrically and/or modularly. 3.- Device according to claim 1 or 2, characterised in 20 that said non-return valves (17 and 18) in the first pipe (14) of the second distribution device (13) are positioned such that they allow for a flow in the direction of one non-return valve to the other non-return valve in the pipe (14) concerned, and in that the above-mentioned non-return 25 valves (19 and 20) in the second pipe (15) of the second distribution device (13) are positioned such that they allow for a flow in the direction away from the other non- return valve in the pipe (15) concerned. red at the EPO on Mar 01,2007 11:58:13. Pi AMENDED SHEET 01/03/2007 ...„V.V_.._„K0_12/. - j?$- 4.- Device according to one or several of the preceding claims, characterised in thai: in the above-mentioned first branch (23) is provided an additional cooler (24). 5 5.- Device according to one or several of the preceding claims, characterised in that between the cut-off valves (7 and 8) in the first pipe (4) of the first distribution device (3) and between the cut-off valves (21 and 22) in the third pipe (16) of the second distribution device 10 (13), is provided a connecting line (37) in which is provided a cut-off valve (38). 6.- Device according to one or several of claims 1 to 5, characterised in that between the cut-off valves (7 and 8) 15 in the first pipe (4) of the first distribution device (3) and between the non-return valves (17 and 18) in the first pipe (14) of the second distribution device (13) is provided a connecting line (39) in which is provided a cut-off valve (40). 20 7. - Device according to one or several of the preceding claims, characterised in that one or several of the above- mentioned cut-off valves (7-12, 21, 22, 29, 38 and 40) are made in the shape of a controlled valve which is connected 25 to a control system, 8.- Device according to any one of the preceding claims, characterised in that the above-mentioned cut-off valves (7-12, 21, 22, 29, 38 and 40) are made in the shape of 30 two-way valves. i at the EPO on Mar 01, 2007 11:58:13. Pi AMENDED SHEET O*#3/£0O7 01013 fM^^^^gi CLMSPAMD BE20G600G 9.- Device according to any one of the preceding claims, characterised in that the above-mentioned first and second distribution devices (3 and 13) have practically the same 5 dimensions. 10.- Device according to any one of the preceding claims, characterised in that the above-mentioned first and second distribution devices (3 and 13) are made as tubular 10 constructions which are identical in shape and which are provided concentrically one above the other. 11.- Device according to claim 10, characterised in that the above-mentioned tubular construction has standard 15 dimensions, such that it can be combined with pressure vessels (31 and 32) having a different volume and for devices (1) having a different capacity. Device for drying a compressed gas in a non-dissipative manner, which mainly consists of a compressed gas supply (2), at least two pressure vessels (31, 32) with an input (33, 34) and an output (35, 36) and take-off point (26), whereby the device (1) is additionally provided with a first distribution device (3) and a second distribution device (13) which is provided with one or several coolers (30) and whereby the device (1) can be controlled by means of nine or ten cut-off valves (7-12, 21,22, 29, 38 and 40).

Full Text

J^^^^^ DESCPAMD 8E20Q6Q001
-4-
Device for drying compressed gas.
The present invention concerns a device for drying a
5 compressed gas.
In particular, the invention concerns a device for drying
compressed gas in a non-dissipative manner, in other words
a device whereby the heat of the compression, present in
10 the compressed gas, is used as a whole or partly to
regenerate the desiccant, and whereby the entire supplied
gas flow flows integrally through the device, without any
part of this gas being blown off in the atmosphere or
being fed back to the output of the device, which results
15 in that such a device has a better efficiency than certain
existing devices.
In particular, the invention concerns a device for drying
a compressed gas in a non-dissipative manner, which mainly
20 consists of a supply of compressed gas, for example in the
shape of a compressed air compressor, at least two
pressure vessels with an input and an output and a take-
off point for compressed gas consumers.
25 Such devices are already known, for example from U.S.
patent No. 6.3.71.377, whereby the above-mentioned pressure
vessels are filled with a dessicant and whereby the gas to
be dried is sent through a first regenerating

ed at the EPO on Mar 01,2007 11:58:13. Pc AMENDED SHEET

01/03/2007

WO 2007/033440 PCT/BE2006/000100
pressure vessel so as to absorb moisture from the
desiccant, by making use of the heat of said compressed
gas, and to thus regenerate this desiccant, and whereby
this gas is subsequently cooled by means of a cooler to
5 be then guided through a second drying pressure vessel
where this cooled gas is dried by the desiccant.
As soon as the desiccant in the drying pressure vessel
is saturated, the flow-through sequence of the pressure
vessels is reversed, such that the first pressure vessel
10 becomes a drying vessel, whereas the second pressure
vessel is turned into a regenerating pressure vessel.
Thus, thanks to the alternating use of the above-
mentioned pressure vessels as a drying and regenerating
pressure vessel, one pressure vessel will always be
15 regenerated by the compressed gas, whereas the other
pressure vessel makes sure that this compressed gas is
subsequently dried.
The known devices for drying a compressed gas in a non-
20 dissipative manner are disadvantageous in that they are
provided with a large number of pipes and valves for
reversing the pressure vessels as regenerating and drying
pressure vessels, and in that they are very large and
expensive and have a complex, non-modular design, such
25 that a large number of variants need to be supported,
which increases the development, production and
maintenance costs.
In order to make the existing devices less complex, use

d* 08/08/2007 DEBOPAMD OE20060001
■•3-
is sometimes made of three-way and/or four-way valves,
which are much more expensive and less reliable than
conventional two-way valves, such that the operational
reliability of the installation as a whole is strongly
5 reduced.
An additional disadvantage for devices with a larger
Capacity for drying compressed gas is that it is often
impossible, or at least economically inefficient to find
10 3-way or 4-way valves which meet the demands as far as
required temperature, pressure and flow are concerned.
US 6.375.722 and WO 03035220 both describe a device for
drying gas in a dissipative manner, whereby part of the
15 gas is blown off in the atmosphere, and whereby said
device comprises at least fourteen valves.
The present invention aims to offer a device for drying a
compressed gas in a non-dissipative manner which does not
20 have the above-mentioned and other disadvantages and which
can be applied to different types of adsorption drying
devices in a simple and cheap manner.
To this end, the present invention concerns a device of
25 the above-mentioned type for drying a compressed gas in a
non-dissipative manner, whereby this device is is
additionally provided with a first distribution device
onto which said compressed gas supply and the take-off
point are connected and which is also connected to each of
30 the respective outputs of the above-mentioned pressure
ed at the EPO on Mar 01. 2007 11 -fift-i-* *>- A»/.
0)008/'
7d: 0S/08/20Q7 DESCPAMD BE20060001
- 3a -
vessels, and whereby the cibove-mentioned first and second
distribution devices are connected to each other, said
device being characterised in that it is provided with
nine or ten cut-off valves; in that said first
5 distribution device comprises three parallel connected
pipes in which are each time provided two cut-off valves
and onto which is each time connected, between two cut-off
valves, a branch, namely a first pipe with a first branch
which provides a connection to the second distribution
10 device, a second pipe with a second branch which is
connected to the above-mentioned take-off point for a
compressed gas consumer; and a third pipe with a third
branch as a connection to the compressed gas supply and a
fourth branch which is connected to the second
15 distribution device via a cut-off valve and in that said
second distribution device comprises three parallel
connected pipes, a first pipe and a second pipe
respectively in which are provided two non-return valves
with an opposite flow direction and a third pipe with two
20 cut-off valves in it, whereby the first pipe, the second
pipe respectively, are each connected between the two non-
return valves, to said fourth branch and the first branch
of the first distribution device respectively, and whereby
the first and the third pipe of the second distribution
25 device are mutually connected via a cooler between the
valves.
By cut-off valves are meant valves which can be controlled
manually or in an automated manner, in other words which
30 can be opened and closed; Non-return valves which cannot
— 4
ed at the EPO on Mar 01.2007 11:58:13. ft AMENDED SHEET HIPN1

„..„«._ 01009/1
S: 08/08/2007 DESCPAMD BE20060001
be controlled as such are considered consequently not
regarded as cut-off valves as meant here.
A really major advantage of such a device according to the
5 present invention is that it only has to be provided with
a relatively limited number of valves compared to the
existing devices for drying a compressed gas in a non-
dissipative manner, as a result of which the device is
cheaper and requires less maintenance costs.
10
If the above-mentioned valves are made in the form of
automatically controlled valves, use can be made in this
specific construction of a relatively simple control
system with a limited number of inputs and outputs, and
15 the control program is simplified as well in comparison
with the known devices.
In a preferred embodiment of a device according to the
invention, the above-mentioned first and second
20 distribution devices are each built symmetrically and/or
modularly.
By a symmetrical construction of the distribution devices
is meant a functional symmetry in this case, and not so
25 much a strictly geometric symmetry. This . **- £f
rtW ->♦ +u- cnA

WO 2007/033440 PCT/BE2006/000100
5
implies that the distribution devices can be made
asymmetrical in shape, but that the device can be
represented by means of a symmetrical functional diagram.
5 A major advantage of such a device according to the
invention is that, thanks to the symmetrical
construction, it contains a large number of common parts,
such as for example pipes and pressure vessels, which
can consequently be produced in larger numbers and thus
10 in a cheaper manner.
Another advantage of a device according to the
invention is that, thanks to the symmetrical
construction, the above-mentioned distribution devices
can be mounted one above the other, such that the length
15 of the connecting lines between both distribution devices
is reduced to a minimum, the device is reduced in size,
and costs are saved.
Another advantage of a device according to the invention
is that, thanks to the combination of the modular
20 construction and the symmetrical arrangement of the
distribution devices, one and the same distribution
device can be combined with pressure vessels having
different diameters. Since the diameter of the pressure
vessels, as opposed to the diameter of the pipes in
25 the distribution device, strongly depends on the flow
rate to be dried, there are usually many more variants
of the pressure vessels than there are variants of
distribution devices.

WO 2007/033440 PCT/BE2006/000100
6
Since, according to the invention, variants of
distribution devices and pressure vessels are
independently interchangeable, less different parts will
need to be kept in stock and production costs can be
5 saved.
In order to better explain the characteristics of the
present invention, the following preferred embodiments
of a device according to the invention for drying a
10 compressed gas are given as an example only without being
limitative in any way, with reference to the accompanying
drawings, in which:
figure 1 schematically represents a device according to the
invention;
15 figures 2 to 5 illustrate the working of a device
according to figure 1;
figure 6 represents a practical embodiment of the device
according to figure 1;
figures 7 and 8 represent a view according to arrows F7 and
20 F8 respectively in figure 6;
figures 9, 14, 19 and 24 represent variants of a device
according to figure 1;
figures 10 to 13, 15 to 18, 20 to 23 and 25 to 28
represent the working of a device according to figures
25 9, 14, 19 and 24 respectively.
Figure 1 represents a device 1 according to the invention
for drying a compressed gas in a non-dissipative manner which
is provided with a compressed gas supply 2, which in this
-case is formed of a compressor and which is connected
30 to a first distribution device 3.

WO 2007/033440 PCT/BE2006/000100
7
The above-mentioned first distribution device 3 is in this
case formed of three parallel pipes which are connected to
each other, a first pipe 4, a second pipe 5 and a third pipe
6 respectively, in which are each time provided two valves 7-
5 8f 11-12 and 9-10 which can be cut off, which in this case,
but not necessarily, are made in the shape of controlled
valves which are connected to a control system which is
not represented in the figures.
10 Further, the device 1 comprises a second distribution
device 13 which in this case has practically the same
dimensions and geometry as the above-mentioned first
distribution device 3 and which also mainly consists of
three parallel pipes 14, IS and 16 which are connected
15 to each other, a first pipe 14 and a second pipe 15
respectively in which are each time provided two non-
return valves 17-18, 19-20 respectively with an
opposite flow direction, and a third pipe 16 with two
valves 21 and 22 in it which can be cut off and which
20 in this case, but not necessarily, are made in the form
of controlled valves as well which are connected to the
above-mentioned control system.
In the given example, the above-mentioned non-return
25 valves 17 and 18 in the first pipe 14 of the second
distribution device 13 are positioned such that they allow
for a flow in the direction of one non-return valve to the
other non-return valve in the pipe 14 concerned, and the
above-mentioned non-return valves 19 and 20 in the
30 second pipe 15 of the second distribution device 13 are

WO 2007/033440 PCT/BE2006/000100
8
positioned such that they allow for a flow in the
direction away from the other non-return valve in the
pipe 15 concerned.
5 It should be noted that the functional diagram in figure 1
of the above-mentioned first and second distribution
device 3 and 13 is built up symmetrically. This symmetry
can also be used in a practical embodiment, such as
represented for example for the distribution devices 3 and
10 13 in figures 6 to 8.
Between the valves 7 and 8 which can be cut off from
the pipe 4 is connected a first branch 23 which provides
a connection to the second distribution device 13 and
which is connected in particular via a cooler 24 to the
15 pipe 15/ between the non-return valves 19 and 20.
In the pipe 5, between the valves 11 and 12 which can be
cut off, is connected a second branch 25 which is
connected to a take-off point 26 for a compressed gas
20 consumer.
Between the valves 9 and 10 which can be cut off from the
pipe 6 is provided a third branch 27 as a connection to
the above-mentioned compressed gas supply 2 and a fourth
branch 28 which is connected to the second distribution
25 device 13 via a valve 29 which can be cut off, in
particular between the non-return valves 17 and 18 in
the pipe 14.
The pipes 14 and 16 are mutually connected between the

WO 2007/033440 PCT/BE2006/000100
9
above-mentioned valves 17-18 and 21-22 via a cooler 30.
Further, the device 1 for drying a compressed gas in a
non-dissipative manner is also provided with two pressure
5 vessels 31 and 32 which are filled with a desiccant, for
example in the form of silica gel, and which are both
provided with an input 33, 34 respectively and an
output 35, 36 respectively.
10 It is clear that instead of silica gel as a desiccant,
also other desiccants can be used.
The above-mentioned first distribution device 3 is
connected to the outputs 35 and 36 of the pressure
15 vessels 31 and 32 with the respective parallel
connections between the pipes 4, 5 and 6, whereas the
second distribution device 13 is connected to the inputs
33 and 34 of these pressure vessels 31 and 32 with the
respective parallel connections between the pipes 14, 15
20 and 16.
According to the invention, the device 1 in this case
has only nine valves 7 to 12, 21, 22 and 29 which can be
cut off, which is less than with the known devices for
drying compressed gas in a non-dissipative manner, so
25 that, partly thanks to the symmetry, a simpler layout is
obtained which is moreover less liable to wear and
consequently requires less maintenance.
The working of a device 1 according to the invention
for drying a compressed gas in a non-dissipative manner

WO 2007/033440 PCT/BE2006/000100
10
is very simple and is illustrated by means of figures 2
to 5, whereby cut-off valves are represented in black
when they are closed in these figures, whereas valves
in their open position are represented in white and the
5 flow of the gas is represented in bold.
In a first phase, which is represented in figure 2, the
pressure vessel 31 is used to regenerate the desiccant
which is present in this pressure vessel 31, and the
pressure vessel 32 is used for drying gas coming from the
10 supply 2.
To this end, the hot, compressed gas coming from the
supply 2 is guided, via the open valve 9, through the
first pressure vessel 31.
15 Moisture which is present in the desiccant in this first
pressure vessel 31 is absorbed by the hot, compressed
gas, such that the desiccant is regenerated in this
first pressure vessel 31.
20 Next, the gas flow goes to the cooler 30 via the non-
return valve 17, where it is cooled, and part of the
moisture situated in the gas flow will condense to be then
guided via the valve 22 through the second pressure
vessel 32, where the gas is dried by the desiccant.
25 The output 36 of the second pressure vessel 32 is
at that time connected via the valve 12 to the take-
off point 26 onto which one or several dried compressed
gas consumers are connected.

WO 2007/033440 PCT/BE2006/000100
11
It is clear that the output coming from the supply 2
flows entirely and without any losses through both
pressure vessels 25 to the take-off point 26.
During a second phase, which is represented in figure 3,
5 and which occurs at the end of the regeneration cycle of
the desiccant in the regenerating pressure vessel 31, the
entire output of compressed gas is successively guided via
the valve 29 through the cooler 30 and via the valve 21
through the first pressure vessel 31, as a result of
10 which this first, regenerating pressure vessel 31 is
cooled.
Next, the gas flows via the valve 7 and the branch 23
through the cooler 24 and the non-return valve 20 to the
second pressure vessel 32 where this gas is dried by the
15 desiccant, after which it flows via the valve 12 and the
branch 25 to the take-off point 26 for compressed gas
consumers.
In a third, subsequent phase, when the desiccant in
20 the drying pressure vessel 32 is almost saturated and/or
the desiccant in the regenerated pressure vessel 31 is
practically cooled, the compressed gas, as represented in
figure 4, is divided for a short time span via the cooler
30 and via the valves 21 and 22 over both pressure
25 vessels 31 and 32. The regenerated pressure vessel
31 is hereby cooled somewhat further, and the almost
saturated pressure vessel 32 is somewhat relieved.
An advantage of cooling the desiccant in the regenerated

WO 2007/033440 PCT/BE2006/000100
12
pressure vessel 31 at the end of the regeneration
cycle is that, at the time the pressure vessels 31 and
32 are changed over, whereby the regenerated pressure
vessel 31 becomes a drying pressure vessel and vice
5 versa, temperature and dew point peaks of the compressed
gas at the take-off point 26 are avoided.
In a fourth and final phase, represented in figure 5,
the entire output of the compressed gas is carried via
the valve 29, the cooler 30 and the valve 22 through the
10 practically saturated second pressure vessel 32, after
which it is guided to the above-mentioned take-off point
26.
After this final phase there is a return to the first
phase, but the pressure vessels 31 and 32 are hereby
15 changed over and the first pressure vessel 31 then
becomes the drying pressure vessel, whereas the second
pressure vessel 32 will be regenerated, etc.
Since it is possible to dry in a non-dissipative manner
with a device 1 according to the invention (save for a
20 pressure drop of the gas between the inlet and the
outlet), energy can be saved in comparison with
devices whereby a part of the compressed gas is fed
back or is blown off in the atmosphere.
In an embodiment of a device 1 according to the
25 invention which is not represented in th-e figures,
heating elements can be provided, either in the
pressure vessels 31 and 32, or outside these pressure

WO 2007/033440 PCT/BE2006/000100
13
vessels 31 and 32, which heating elements are designed to
better regenerate the desiccant, and to thus further
reduce the dew point of the gas at the outlet of the
device 1.
5 Figures 6 to 8 represent a practical embodiment of a
device according to figure 1, whereby the first and
second distribution device, 3 and 13 respectively, are
made symmetrical by means of tubular constructions which
are identical in shape and which are provided
10 concentrically on top of each other.
In the given example, the above-mentioned tubular
constructions are made according to standard dimensions,
such that they can be combined with pressure vessels 31
15 and 32 having different volumes and for devices 1 having
different capacities. Thus, the arrangement of the
pressure vessels and tubular construction is modular, as
a result of which the number of variants for the
production is restricted and costs are saved.
20 In this case, the above-mentioned branches and
connections can be realised in a simple manner by means
of short pipes or lines provided between the tubular
constructions situated on top of each other.
Figure 9 r-epresents another embodiment of a device 1
25 according to the invention, whereby no cooler is
provided in the above-mentioned first branch 23 of the
first distribution device 3 in this case.

WO 2007/033440 PCT/BE2006/000100
14
This will reduce the cost of the device even further,
whereas it is nevertheless possible to obtain a good
output with the device 1.
5 The working of this variant is practically analogous to
that of the preceding embodiment.
The first, third and fourth phases as represented in
figures 10, 12 and 13 respectively, are identical to the
first, third and fourth phases of the preceding
10 embodiment, as represented in figures 2, 4 and 5
respectively.
The second phase, which is represented in figure 11, is
somewhat different in this embodiment from the one
described above.
15 During this second phase, the entire output of gas to be
dried is directed via the valve 29 through the cooler 30
in this case, after which this gas flows via the valve 22
to the input 34 of the second, drying pressure vessel 32
so as to be dried.
20 Next, the dried compressed gas flows via the valve 8 and
through the first branch 23 of the first distribution
device 3 to the pipe 15, where this gas flows via the
non-return valve 19 to the regenerating pressure vessel
31 so as to then be carried via the branch 25 to the
25 take-off point 26.
Since the compressed gas is cooled and dried first,

WO 2007/033440 PCT/BE2006/000100
15
before flowing through the regenerating pressure vessel
31, this gas will cool said regenerating pressure
vessel 31.
Figure 14 represents yet another embodiment of a device
5 1 according to the invention for drying a compressed gas
in a non-dissipative manner, whereby a connecting line
37 is provided between the valves 7 and 8 in the pipe
4 and between the valves 21 and 22 in the pipe 16, in
which is provided a valve 38 which can be cut off.
10 In this case, the device 1 according to the invention
is controlled by means of ten cut-off valves, which is
considerably less than with known devices which make it
possible to go through the same phases and to dry in a
non-dissipative manner.
15 The working of such an embodiment according to figure 14 is
practically analogous to that of the first embodiment and it
is represented in figures 15 to 18.
In a first phase, which is represented in figure 15, the
hot compressed gas is first guided via the valve 9 through
20 the regenerating pressure vessel 31, after which the damp gas
is guided via the non-return valve 17, the cooler 30 and the
valve 38 through the branch 23 and the cooler 24 to
subsequently flow through the non-return valve 20 to the
drying pressure vessel 32 where it is dried.
25 The dried -compressed gas is finally carried via the valve 12
and the branch 25 to the above-mentioned take-off point 26 for

WO 2007/033440 PCT/BE2006/000100
16
compressed gas consumers.
Consequently, the coolers 30 and 24 are connected in series
in this case, as a result of which the cooling capacity is
increased and as a result of which the gas can be dried more
5 efficiently. This results in a lower dew point of the
compressed gas at the take-off point of the dryer.
During the second phase, which is represented in figure 16,
the gas flows through the device 1 in an identical manner as
during the second phase of the device, as is represented in
10 figure 3, whereby the regenerating pressure vessel 31 is
cooled.
During the third and the fourth phase, which are represented
in figures 17 and 18 respectively, the above-mentioned
coolers 30 and 24 are each time connected in series by
15 opening the valve 38 and closing the valve 22.
In the third phase, after flowing through the coolers 30
and 24, the gas is split up via the non-return valves 19
and 20 in the pipe 15 to the regenerating pressure vessel
31 on the one hand and the drying pressure vessel 32 on the
20 other hand.
Next, these split gas flows come together again via the
valves 11 and 12 in the branch 25 so as to be guided to
the take-off point 26.
During the fourth phase, the entire compressed gas
25 flow, cooled by the coolers 30 and 24, is sent through

WO 2007/033440

PCT/BE2006/000100

17
the drying pressure vessel 32, after which it flows via
the branch 25 to the take-off point 26.
By analogy with the preceding embodiments, the drying
pressure vessel 31 is afterwards changed over to the
5 regenerating pressure vessel 32.
It should be noted that, in this embodiment of the device
1, both available coolers 30 and 24 can be used in any
phase of the drying process, and thus, in every phase,
the compressed gas is maximally cooled before flowing into
10 the drying pressure vessel 31, which results in a minimal
dew point of the gas at the take-off point 26.
Figure 19 represents another variant of a device 1
according to figure 1 whereby, in this case, a
15 connecting line 39 is provided between the valves 7
and 8 which can be cut off in the pipe 4 and between the
non-return valves 17 and 18 in the pipe 14, in which is provided
a valve 40 which can be cut off.
The working of such a variant is analogous to that of the
20 preceding embodiment, whereby in this case however, in the
first, third and fourth phase, the coolers 30 and 24 are
connected in parallel, as a result of which the cooling
capacity will be considerably higher than with a single cooler,
and the gas can be dried better.
25 Moreover, by connecting the coolers 30 and 24 in parallel, the
pressure drop over these coolers 30 and 24 will be lower than
when these coolers 30 and 24 are connected in series.

WO 2007/033440 PCT/BE2006/000100
18
The coolers 30 and 24 are connected in series, as is
represented in figures 20, 22 and 23, by opening the valves 40
and 22 which can be cut off.
Figure 24 represents yet another embodiment of a device
5 according to figure 1, whereby three pressure vessels 41, 42
and 4 3 are provided which are connected to a first
distribution device 44 with their outputs and to a second
distribution device 45 with their inputs.
The above-mentioned first distribution device 44 in this case
10 consists of three main pipes, namely a first 30 main pipe
46 onto which are connected three branches 47 to 49; a second
main pipe 50 with branches 51 to 53; and a third main pipe 54
with branches 55 to 57.
Each of the above-mentioned branches 47 to 49, 51 to 53
15 and 55 to 57 is connected to the output of a
respective pressure vessel 41, 42 and 43.
In the branches 4 7 to 4 9 and 51 to 53 is each time
provided a cut-off valve, whereas in each of the
20 branches 55 to 57 is provided a non-return valve which is
positioned such that it allows for a flow to the
respective pressure vessel 41, 42, 43 with which the
branch 55 to 57 concerned is connected.
25 The main pipes 46 and 54 are connected to each other by
means of a bypass 58, and the above-mentioned supply 2
for compressed gas is directly connected to the main
pipe 50.

WO 2007/033440 PCT/BE2006/000100
19
The second distribution device 45 is built in
practically the same manner as the first distribution
device 44, and it is also provided with three main
pipes, a first main pipe 59 with three branches 60 to
5 62; a second main pipe 63 with branches 64 to 66; and a
third main pipe 61 with branches 68 to 70 respectively.
Each of the above-mentioned branches 60 to 62, 64 to 66
and 68 tot 70 is connected to the input of a respective
10 pressure vessel 41, 42 and 43.
In the branches 60 to 62 and 64 to 66 is each time
provided a cut-off valve, whereas in each of the
branches 68 to 70 is provided a non-return valve which is
positioned such that it allows for a flow from the
15 respective pressure vessels 41, 42, 43 with which the
branches 68 to 70 concerned are connected.
The main pipes 63 and 67 of the second distribution
device 45 are connected to each other via a cooler 71.
The above-mentioned main pipe 54 is connected to the
20 main pipe 59 and to the take-off point 26 for compressed
gas consumers by means of a first connecting line 72
having a valve 73 which can be cut off provided in it.
The above-mentioned main pipe 50 is connected to the
main pipe 67 by means of a second connecting line 74, in
25 which is provided a valve 75 which can be cut off.
The working of a device 1 according to figure 24 is

WO 2007/033440 PCT/BE2006/000100
20
represented step by step in figures 25 to 28.
In a first phase, the first pressure vessel 41 is
regenerated, whereas the second and third pressure
vessels 42 and 43 both form drying pressure vessels.
5 The hot compressed gas is in this first phase
directed via the branch 51 through the pressure vessel
41, where the hot gas absorbs moisture from the
desiccant, as a result of which this pressure vessel
41 is regenerated.
10 Next, the damp, compressed gas flows via a non-return
valve in the branch 68 to the cooler 71, after which
the cooled gas flows through the valves in the
branches 65 and 66 to the pressure vessels 42 and 4 3 to
be dried.
15 The dried compressed gas is then directed through the valves
in the branches 48 and 4 9 and via the main pipe 46 to
the bypass 58 and afterwards, via the connecting line 72, to
the take-off point 26.
In the second phase, which is represented in figure 26, the hot
20 compressed gas, coming from the supply 2, is first directed
via the connecting line 74 and the main pipe 67 through the
cooler 71 to subsequently flow via the branches 65 and 66 to
the pressure vessels 42 and 43 so as to be dried there.
The dried compressed gas is then directed via the branches 48
25 and 49 and via the bypass 58 through the non-return valve in

WO 2007/033440 PCT/BE2006/000100
21
the branch 55 into the first pressure vessel 41 which is
cooled by the gas.
Finally, the gas flow is directed via the branch 60 to the
take-off point 26.
5 In the third phase, which is represented in figure 27, the
hot compressed gas is first directed via the connecting line
74 and the main pipe 67 through the cooler 71 to be
subsequently split and be directed via each of the
branches 64 to 66 to the respective pressure vessels 41
10 to 43.
Next, the split gas flows are directed via the branches 47 to
49 to flow together again in the main pipe 46 and to be
carried via the bypass 58 and the connecting line 72 to the
take-off point 26.
15 The first pressure vessel 41 is cooled further in this
third phase, since the supplied gas is first directed
through the cooler 71.
During the fourth and final phase which is represented in
20 figure 28, the entire output of compressed gas is directed
via the connecting line 74 and the main pipe 67 through
the cooler 71.
Next, the gas flows through the cut-off valves in the
25 branches 65 and 66 to the pressure vessels 42 and 4 3, to
then flow via the branches 48 and 4 9 and the bypass 58
to the connecting line 72 and the take-off point 26.

WO 2007/033440 PCTYBE2006/000100
22
Such an embodiment of device 1 for drying a compressed
gas in a non-dissipative manner with three pressure
vessels 41, 42 and 43 has more cut-off valves 20 than the
above-described embodiments, but the layout appears to be
5 considerably simpler than the existing ones with three
pressure vessels, such that this device 1 can be realised
in a relatively cheap manner.
It is clear that in all the embodiments of a device 1
according to the invention, the cut-off valves may be
10 electrically controllable, but they can also be
controlled in other ways, such as for example in a
pneumatic manner or the like, or they can even be
manually controllable.
The present invention is by no means limited to the
15 embodiments described as an example and represented in the
accompanying drawings; on the contrary, such a device 1
according to the invention for drying a compressed gas
in a non-dissipative manner can be made in all sorts of
shapes and dimensions while still remaining within the
20 scope of the invention.

LflOlO/i
BE20G60001
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Claims.
1.- Device for drying a compressed gas in a non-
5 dissipative manner, which mainly consists of a compressed
gas supply (2), two pressure vessels (31,32) with an input
(33,34) and an output (35,36), and a take-off point (26)
for compressed gas consumers, whereby the above-mentioned
device (1) is additionally provided with a first
10 distribution device (3) onto which said compressed gas
supply (2) and the take-off point (26) are connected and
which is also connected to each of the respective outputs
(35 and 36) of the above-mentioned pressure vessels (31
and 32), and whereby the above-mentioned first and second
15 distribution devices (3 and 13) are connected to each
other, characterised in that the device (1) is provided
with nine or ten cut-off valves (7-12, 21, 22, 29, 38 and
40); in that said first distribution device (3) comprises
three parallel connected pipes (4, 5 and 6) in which are
20 each time provided two cut-off valves (7,8; 9,10; 11,12)
and onto which is each time connected, between two cut-off
valves (7,8; 9,10; 11,12), a branch, namely a first pipe
(4) with a first branch (23) which provides a connection
to the second distribution device (13), a second pipe (5)
25 with a second branch (25) which is connected to the above-
mentioned take-off point (26) for a compressed gas
consumer; and a third pipe (6) with a third branch (27) as
a connection to the compressed gas supply (2) and a fourth
branch (28) which is connected to the second distribution
30 device (13) via a cut-off valve (29) and in that said

ived at the EPOon Mar 01, 2007 11:58:13. P
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second distribution device (13) comprises three parallel
connected pipes {14, 15 and 16), a first pipe (14) and a
second pipe (15) respectively in which are provided two
non-return valves (17,10 and 19,20) with an opposite flow
5 direction and a third pipe (16) with two cut-off valves
(21 and 22) in it, whereby the first pipe (14), the second
pipe (15) respectively, are each connected between the two
non-return valves (17,18 and 19,20), to said fourth branch
(28) and the first branch (23) of the first distribution
10 device (3) respectively, and whereby the first and the
third pipe (14 and 16) of the second distribution device
(13) are mutually connected via a cooler (30) between the
valves (17,18 and 21,22).
15 2.- Device according to claim 1, characterised in that the
above-mentioned first and second distribution devices (3
and 13) are each built symmetrically and/or modularly.
3.- Device according to claim 1 or 2, characterised in
20 that said non-return valves (17 and 18) in the first pipe
(14) of the second distribution device (13) are positioned
such that they allow for a flow in the direction of one
non-return valve to the other non-return valve in the pipe
(14) concerned, and in that the above-mentioned non-return
25 valves (19 and 20) in the second pipe (15) of the second
distribution device (13) are positioned such that they
allow for a flow in the direction away from the other non-
return valve in the pipe (15) concerned.

red at the EPO on Mar 01,2007 11:58:13. Pi AMENDED SHEET

01/03/2007

...„V.V_.._„K0_12/.
- j?$-
4.- Device according to one or several of the preceding
claims, characterised in thai: in the above-mentioned first
branch (23) is provided an additional cooler (24).
5 5.- Device according to one or several of the preceding
claims, characterised in that between the cut-off valves
(7 and 8) in the first pipe (4) of the first distribution
device (3) and between the cut-off valves (21 and 22) in
the third pipe (16) of the second distribution device
10 (13), is provided a connecting line (37) in which is
provided a cut-off valve (38).
6.- Device according to one or several of claims 1 to 5,
characterised in that between the cut-off valves (7 and 8)
15 in the first pipe (4) of the first distribution device (3)
and between the non-return valves (17 and 18) in the first
pipe (14) of the second distribution device (13) is
provided a connecting line (39) in which is provided a
cut-off valve (40).
20
7. - Device according to one or several of the preceding
claims, characterised in that one or several of the above-
mentioned cut-off valves (7-12, 21, 22, 29, 38 and 40) are
made in the shape of a controlled valve which is connected
25 to a control system,
8.- Device according to any one of the preceding claims,
characterised in that the above-mentioned cut-off valves
(7-12, 21, 22, 29, 38 and 40) are made in the shape of
30 two-way valves.
i at the EPO on Mar 01, 2007 11:58:13. Pi AMENDED SHEET O*#3/£0O7

01013
fM^^^^gi CLMSPAMD BE20G600G
9.- Device according to any one of the preceding claims,
characterised in that the above-mentioned first and second
distribution devices (3 and 13) have practically the same
5 dimensions.
10.- Device according to any one of the preceding claims,
characterised in that the above-mentioned first and second
distribution devices (3 and 13) are made as tubular
10 constructions which are identical in shape and which are
provided concentrically one above the other.
11.- Device according to claim 10, characterised in that
the above-mentioned tubular construction has standard
15 dimensions, such that it can be combined with pressure
vessels (31 and 32) having a different volume and for
devices (1) having a different capacity.

Device for drying a compressed gas in a non-dissipative manner,
which mainly consists of a compressed gas supply (2), at least
two pressure vessels (31, 32) with an input (33, 34) and an output
(35, 36) and take-off point (26), whereby the device (1) is
additionally provided with a first distribution device (3) and a
second distribution device (13) which is provided with one or
several coolers (30) and whereby the device (1) can be
controlled by means of nine or ten cut-off valves (7-12, 21,22, 29, 38 and 40).

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Patent Number

270636

Indian Patent Application Number

1088/KOLNP/2008

PG Journal Number

02/2016

Publication Date

08-Jan-2016

Grant Date

06-Jan-2016

Date of Filing

13-Mar-2008

Name of Patentee

ATLAS COPCO AIRPOWER, NAAMLOZE VENNOOTSCHAP

Applicant Address

BOOMSESTEENWEG 957, B-2610 WILRIJK

Inventors:

#	Inventor's Name	Inventor's Address
1	HUBERLAND, FILIP, GUSTAAF, M.	WOUWENDONKSTRAAT 13/16, B-2570 DUFFEL

PCT International Classification Number

B01D 53/26

PCT International Application Number

PCT/BE2006/000100

PCT International Filing date

2006-09-14

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005/0460	2005-09-22	Belgium