Title of Invention

PLASTIC SAFETY VALVE FOR CONTAINERS

Abstract

The safety valve (I), which is used, for example, for the internal plastic container of a pallet container for the transport and storage of liquids, consists of an aerating unit (2) and a venting unit (3), which are integrated into a valve housing (4), designed as a threaded plug. When negative pressure develops in the internal container of the pallet container during the removal of liquid, the valve membrane (11) of the venting unit (2) opens, so that air can flow through the safety valve (I) into the container in the direction of arrow a. The stiffness of the valve plate (45) of the venting unit (3) of the safety valve (I) is calculated in such a way that a positive pressure of, for example, 80 mbars can build up in the inside container, as a result of which the container is stabilized. When the pressure in the container exceeds the limit, the valve plate (45) opens, so that air or gas can escape from the container through the safety valve (J) in the direction of arrow b.

Full Text

SPECIFICATION PLASTIC SAFETY VALVE FOR CONTAINERS The Invention pertains to a plastic safety valve for containers, especially pallet containers with an internal container of plastic and an external jacket of metal for the transport and storage of liquids, the valve being designed as an automatic aerating and venting valve, which is integrated into a lid or plug for sealing the filling and/or emptying opening or the aerating and/or venting opening of a container. DE 2,501,228 Al describes a sealing cap, intended for containers for liquid, which can be screwed onto the neck of a bung. A safety valve of the general type in question here is integrated into this cap to serve as an aerating and venting valve, which responds to positive and negative pressures in the container. A valve disk of elastic material is used in this safety valve; when the disk is first installed, it is put under a significant amount of pretension and thus assumes the form of a segment of a sphere. When this type of valve is used, there is the danger that fatigue phenomena affecting the valve disk material will cause leaks to form after prolonged periods of service. The invention is based on the task of developing a safety valve of the general type in question which meets the highest safety requirements. This task is accomplished In accordance with the invention by a safety valve with the features of Claim 1. The sub claims contain advantageous further elaborations of the invention. The safety valve according to the invention is characterized by the highest functional reliability and satisfies the safety guidelines described above. In the case of pallet containers, it is the flexible internal plastic container which is equipped with the safety valve. Containers of this type have a nominal content of, for example, 1,250 liters, and a positive pressure, which can be regulated by the venting unit of the safety valve, can build up inside them; this pressure stabilizes the internal container and prevents the internal container from "breathing" during transport. Breathing is associated with forcible contact between the container walls and the external metal grid jacket or external sheet-metal jacket of the pallet container, which means that, by preventing breathing, it is also possible to prevent the internal container from developing leaks during transport. Accordingly the present invention provides a safety valve made of plastic material for tanks for transporting and for storing liquids, which valve is configured as an automatic air-inlet valve and air-release valve and is integrated in a screw cap or stopper for closing the filling and/or discharge opening or the air-inlet and/or air-release opening of a tank, a valve housing, which is configured as a threaded stopper and is screw able into a corresponding threaded boring of the screw cap or threaded stopper, has a centric hub retained by ribs with a through-boring, the ribs extending from the hub in a star shape externally towards an annular shoulder and air passage openings being formed between the ribs, in addition a resiliency configured valve membrane of an air-inlet unit for opening and closing the air passage openings is pushed between the ribs from the inside onto the hub up to a shoulder of the same, the valve membrane configured as a cap profile with a cap profile opening being incorporated in said valve housing directed towards the annular shoulder of the valve housing and, in the closed position of the air-inlet unit, abutting with an annular edge with Initial tension against an internal side of the annular shoulder of the valve housing, which annular shoulder forms a valve face, that an air-release unit is inserted in an external end of the through-boring of the hub, which unit has a valve disc made of elastic material, which valve disc is placed with its lower side on an external edge of the hub, which external edge forms a valve face and is bevelled inwardly, and which valve disc is retained in the through-boring of the hub, that a surge cap is pressed on an internal end of the hub, the external edge of which surge cap forms with the internal end of the valve housing a surrounding passage slot for the air or gas, which enters into the tank when the air-inlet unit is opened and which discharges from the tank when the air-release unit is opened and the surge cap serves at the same time for securing the valve membrane on the hub, that, between the valve membrane and the surge cap, a surge disc is inserted in the valve housing coaxially to the membrane and to the surge cap, said surge disc having at least one passage opening for the air or the gas and forming together with the surge cap a labyrinth as a protection for the valve membrane against the surge liquid penetrating into the valve housing, that a clamping sleeve with axial clamping webs is formed on the curved surge cap, which clamping sleeve presses the valve membrane with the securing hub against the shoulder of the hub of the valve housing that, between the clamping sleeve of the surge cap and the hub of the valve housing, there are disposed flow channels, which communicate with through-slots in the internal end of the clamping sleeve and with through-slots in the internal end of the hub and are formed by the axial clamping webs of the clamping sleeve, said flow channels being for the air and/or gas which flows out of the tank via the passage slot between the surge cap and valve housing and the passage opening of the surge disc at excess pres-sure towards the air-release unit and that, at the external edge of the valve housing, which edge abuts against the annular shoulder, retaining teeth are formed for a sealing cap which can be securely clamped on said valve housing, there being formed between the retaining teeth and the sealing cap, which protrudes externally beyond the latter, passage openings for the air streaming Into the tank through the air-inlet unit, when the valve membrane is opened, and for the air or gas flowing out of the tank through the air-release unit when the valve disc is opened. The invention is explained below on the basis of drawings, which illustrate the following: -Figure 1 shows a longitudinal cross section of a safety valve, designed as an aerating and venting valve, on an enlarged scale; and -Figure 2 shows a top view onto the valve of Figure 1 without its sealing cap. Safety valve 1 according to Figures 1 and 2 for tanks, barrels, pallet containers, and similar containers for the transport and storage of liquids is made of plastic and consists of an aerating unit 2 and a venting unit 3, which are integrated into a valve housing 4, which is itself designed as a threaded plug. Valve housing 4 is screwed into a threaded plastic lid 5 used to seal the filling opening of the internal plastic container of a pallet container. The housing is sealed in threaded lid 5 by a sealing ring 6. The housing has a central hub 7, supported by ribs 8, which extend out from hub 7 in a star-like manner to a ring-shaped shoulder 9. Air holes 10 are formed between support ribs 8. An elastic valve membrane 11 of aerating unit 2 for opening and closing air holes 10 is made out of a flexible material resistant to aggressive fluids such as plastic or rubber with appropriate additives. This membrane is designed with the profile of a hat 12 and has a central, reinforced mounting hub 13. With opening 14 of the hat pointing toward ring-shaped shoulder 9 of valve housing 4, valve membrane II is pushed onto hub 7 of the valve housing as far as a shoulder 15 on the housing. Valve membrane 11 is held on the hub by a surge cover 17, which is pressed onto inner end 16 of hub 7. A clamping sleeve 18 with axial clamping webs 19 is molded onto curved surge cover 17; these webs press valve membrane 11 by its mounting hub 13 against shoulder 15 of hub 7 of valve housing 4 in such a way that, when aerating unit 2 is in its closed position, valve membrane 11 rests by a ring-shaped edge 20 under pretension against the inside surface 21 of ring-shaped shoulder 9 of valve housing 4, which forms a valve seat. Valve membrane 11 is also supported by a ring-shaped web 23 molded onto inside edge 22 of ring-shaped shoulder 9. Flow channels 28 for the air or gas escaping under pressure from a container through venting unit 3 are provided f between clamping sleeve 18 of surge cover 17 and hub 7 of valve housing 4, these channels being connected to each other by through-slots 24 in inner end 25 of clamping sleeve 18 and through-slots 26 in inner end 16 of hub 7 of valve housing 4. Support ribs 8 of hub 7 have a profile 29 which conforms to hat-shaped profile 12 of valve membrane 12 so that they can effectively support the valve membrane against positive pressure in the container. Outer edge 30 of surge cover 17 cooperates with inner end 31 of valve housing 4 to form a peripheral slot 32 for the air entering a container when aerating unit 2 is open and for the air or gas escaping from a container when venting unit 3 is open. Between valve membrane 11 and surge cover 17, a surge disk 33 with a hat-shaped profile 34, coaxial to the membrane and the lid, is provided; this profile has a central opening 35 for air or gas. Surge disk 33 cooperates with surge cover 17 to form a labyrinth, which protects valve membrane 11 against surges of liquid entering safety valve 2. The curved surface of surge cover 17 facing valve membrane 21, furthermore, forms a run-off surface 38 for the surging liquid which has entered safety valve 2. Axial clamping tabs 40 are molded onto outside surface 39 of surge cover 17. Distributed uniformly around the periphery of the cover, they press surge disk 33 against a shoulder 42 on inside surface 42 of valve housing 4. Venting unit 3, inserted into the outer end 43 of through-hole 44 in hub 7 of valve housing 4, is equipped with a valve plate 45 of elastic material. The bottom surface of this plate rests on inward-beveled, outer edge 46 of hub 7, which forms a valve seat, A mounting pin 47 with a head 48 is molded onto valve plate 45 to form a single unit with it; this pin locks behind an undercut 49 in through-hole 44 of hub 7 to fasten valve plate 45, which rests under slight pretension on outer edge 46 of hub 7. On the periphery of mounting pin 47 and head 48, continuous axial air or gas through-channels 50, 51 are provided. A grid 53 of plastic is welded to external surface 52 of ring-shaped shoulder 9 of valve housing 4. This grid covers air holes 10 between support ribs 8 of hub 7 as protection against the intrusion of insects. On outer edge 54 of valve housing 4, adjacent to ring-shaped shoulder 9, hook-shaped retaining teeth 55 are provided to engage with a sealing cap 56, which can thus be clamped firmly to the housing. Openings 57 for the air flowing into a container when aerating unit 2 of safety valve 1 is open and for the air or gas flowing out of a container when venting unit 3 is open are provided between retaining teeth 55 and sealing cap 56, which projects out-ward beyond the teeth. On inside surface 58 of sealing cap 56, a certain radial distance away from its outer edge 59, a ring-shaped web 60 with an undercut 61 is formed; when sealing cap 56 is pressed down onto valve housing 4, this undercut interlocks with retaining teeth 55 of the housing. Four molded segments 62 on outside surface 52 of ring-shaped shoulder 9 serve to accept a spider wrench for screwing safety valve 1 into and out of threaded lid 5. When negative pressure, for example, develops in the internal plastic container of a pallet container equipped with safety valve 1 as liquid is being removed, valve membrane 11 of aerating unit 2 opens, so that air can flow into continuous air openings 55, 10, 35, 32 of safety valve 1 in the direction of arrow as shown in Figure 1. The stiffness of valve plate 45 of venting unit 3 of safety valve 1 is to be calculated in such a way that a positive pressure between 50-120 mbars, in particular, 80 mbars, can build up in the internal container of the pallet container and thus stabilize the container. When the positive pressure in the container exceeds the cited limit, valve plate 45 of venting unit 3 of safety valve 1 opens, so that the air or gas which is under positive pressure can escape from the container in the direction of arrow b through air openings and flow channels 32, 35, 24t 28, 26, 44, 51, 50, 10, and 57 of safety valve 1. WE CLAIM: 1. A safety valve (1) made of plastic material for tanks for transporting and for storing liquids, which valve is configured as an automatic air-inlet valve and air-release valve and is integrated in a screw cap (5) or stopper for closing the filling and/or discharge opening or the air-inlet and/or air-release opening of a tank, a valve housing (4), which is configured as a threaded stopper and is screwable into a corresponding threaded boring of the screw cap (5) or threaded stopper, has a centric hub (7) retained by ribs (8) with a through-boring (44), the ribs (8) extending from the hub (7) in a star shape externally towards an annular shoulder (9) and air passage openings (10) being formed between the ribs (8), in addition a resiliency configured valve membrane (11) of an air-inlet unit (2) for opening and closing the air passage openings (10) is pushed between the ribs (8) from the inside onto the hub (7) up to a shoulder (15) of the same, the valve membrane (11) configured as a cap profile (12) with a cap profile opening (14) being incorporated in said valve housing directed towards the annular shoulder (9) of the valve housing (4) and, in the closed position of the air-inlet unit (2), abutting with an annular edge (20) with Initial tension against an internal side (21) of the annular shoulder (9) of the valve housing (4), which annular shoulder forms a valve face, that an air-release unit (3) is inserted in an external end (43) of the through-boring (44). of the hub (7), which unit has a valve disc (45) made of elastic material, which valve disc is placed with its lower side on an external edge (46) of the hub (7), which external edge forms a valve face and is bevelled inwardly, and which valve disc is retained in the through-boring (44) of the hub (7), that a surge cap (17) is pressed on an internal end (16) of the hub (7), the external edge (30) of which surge cap forms with the internal end (31) of the valve housing (4) a surrounding passage slot (32) for the air or gas, which enters into the tank when the air-inlet unit (2) is opened and which discharges from the tank when the air-release unit (3) is opened and the surge cap (17) serves at the same time for securing the valve membrane (11) on the hub (7), that, between the valve membrane (11) and the surge cap (17), a surge disc (33) is inserted in the valve housing (4) coaxially to the membrane (11) and to the surge cap (17), said surge disc having at least one passage opening (35) for the air or the gas and forming together with the surge cap (17) a labyrinth as a protection for the valve membrane (11) against the surge liquid penetrating into the valve housing (4), that a clamping sleeve (18) with axial clamping webs (19) is formed on the curved surge cap (17), which clamping sleeve presses the valve membrane (11) with the securing hub (13) against the shoulder (15) of the hub (7) of the valve housing (4) that, between the clamping sleeve (18) of the surge cap (17) and the hub (7) of the valve housing (4), there are disposed flow channels, which communicate with through-slots (24) in the internal end (25) of the clamping sleeve (18) and with through-slots (26) in the internal end (16) of the hub (7) and are formed by the axial clamping webs (19) of the clamping sleeve (18), said flow channels being for the air and/or gas which flows out of the tank via the passage slot (32) between the surge cap (17) and valve housing (4) and the passage opening (35) of the surge disc (33) at excess pres- sure towards the air-release unit (3) and that, at the external edge (54) of the valve housing (4), which edge abuts against the annular shoulder (9), retaining teeth (55) are formed for a sealing cap (56) which can be securely clamped on said valve housing, there being formed between the retaining teeth (55) and the sealing cap (56), which protrudes externally beyond the latter, passage openings (57) for the air streaming Into the tank through the air-inlet unit (2), when the valve membrane (11) is opened, and for the air or gas flowing out of the tank through the air-release unit (3) when the valve disc (45) is opened. 2. The safety valve according to claim 1, wherein the retaining ribs (8) of the hub (7) have a profile, which is adapted to the cap profile (12) of the valve membrane (11) for supporting the valve membrane (11) in the case of excess pressure in the tank and In that the valve membrane (11) is supported in addition by an annular web (23) formed on the internal edge (22) of the annular shoulder (9) 9f the valve housing (4). 3. The safety valve according to claim 1 or 2, wherein the valve membrane (11), which is produced from a flexible material, which Is resistant to aggressive liquids, such as plastic material or rubber with corresponding supplements, has a central, reinforced securing hub (13) 4. The safety valve according to any one of the claims 1 to 3, wherein the curve of the surge cap (17), which curve is directed towards the valve membrane (11), forms a discharge face (38) for the surge liquid which has entered the safety valve (1). 5. The safety valve according to any one of the claims 1 to 4, wherein the surge disc (33) has a cap profile (34) with a central passage opening (35) for air or gas. 6. The safety valve according to any one of the claims 1 to 5, wherein axial clamping noses (40), which are formed on the external side (39) of the surge cap (17) and are distributed across the cap circumference, in order to press the surge disc (33) against a shoulder (41) on the internal side (42) of the valve housing (4). 7. The safety valve according to any one of the claims 1 to 6, wherein the surge disc (33) is incorporated in the valve housing (4) with the cap profile opening (36) pointing towards the valve membrane (11) and forms a discharge face (37) for surge liquid which penetrates into the valve (1). 8. The safety valve according to any one of the claims 1 to 7, wherein an automatic control of excess pressure in the tank by means of the air-release unit (3). 9. The safety valve according to claim 8, wherein a control of the excess pressure in the tank by the air-release unit (3) at 50 to 120 millibar, preferably 80 millibar. 10. The safety valve according to any one of the claims 1 to 9, wherein a securing pin (47) with a head (48) is formed integrally on the valve disc (45) of the air-release unit (3), which securing pin is locked with an undercut (49) of the through-boring (44) of the hub (7) in order to secure the valve disc (45), which abuts under slight initial tension against the external edge (46) of the hub (7) of the valve housing (4), axial air-or gas-passage channels (50, 51) being disposed on the circumference of the securing pin (47) and its head (48) while graduating into each other. 11. The safety valve according to any one of the claims 1 to 10, wherein a grating (53), which is fixed on the external side (52) of the annular shoulder (9) of the valve housing (4) and is preferably made of plastic material, said grating covering the air-passage openings (10) between the retaining ribs (8) of the hub (7) as protection against penetration of vermin. 12. The safety valve according to claim 11, wherein the grating (53) is welded onto the external side (52) of the annular shoulder (9). 13. The safety valve according to any one of the claims 1 to 12, wherein hook-shaped retaining teeth (55), which are formed on the external edge (54) of the valve housing (4) in order to securely clamp the sealing cap (56), on the internal side (58) of which an annular web (60) with an undercut (61) is formed with radial spacing from the external edge (59), said annular web locking during clamping of the sealing cap (56) on the valve housing (4) with the retaining teeth (55) of the same. 14. A safety valve made of plastic material for tanks for transporting and for storing liquids substantially as herein described with reference to the accompanying drawings.

Documents:

2683-MAS-1998 CORRESPONDENCE OTHERS 01-07-2010.pdf

2683-MAS-1998 CORRESPONDENCE OTHERS 13-07-2012.pdf

2683-MAS-1998 CORRESPONDENCE OTHERS.pdf

2683-MAS-1998 FORM-2.pdf

2683-MAS-1998 FORM-4.pdf

2683-mas-1998- abstract.pdf

2683-mas-1998- claims.pdf

2683-mas-1998- correspondence others.pdf

2683-mas-1998- correspondence po.pdf

2683-mas-1998- description complete.pdf

2683-mas-1998- drawings.pdf

2683-mas-1998- form 1.pdf

2683-mas-1998- form 26.pdf

2683-mas-1998- form 3.pdf

2683-mas-1998- form 4.pdf