Title of Invention

"A CAPILLARY VISCOMETER DEVICE TO DETERMINE THE FLOW CHARATERISATICS OF FLUIDS"

Abstract

A capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid which comprises an inner cylinder (1) made of heat conducting materials, and an outer cylinder (2) of capacity covered with an insulated sheet, the test fluid being kept in the said inner cylinder(l) which is being connected with a manometer (14) by means of capillary being surrounded by glass tube (7) to monitor the pressure in the inner cylinder(l), the said outer cylinder(2) containing constant temperature water bath being maintained by a heater (3) and being uniformly distributed by continuous stirring by means of a stirrer and its speed being controlled by a motor (5) , one inlet of the said capillary (12) being connected to the bottom of the said inner cylinder (1), outlet of the said capillary being put to a beaker (13) to determine the flow rate of the lost fluid, the capillary tube being put inside a cylinder containing constant temperature water bath by means of tube (8)&(9) , the inlet of a tube (6) being connected to the said outer cylinder & the outlet (11) being connected to the upper half of the cylinder containing capillary (12), inlet of other tube (9) being connected to the lower part of the cylinder containing capillary (12) & outlet being connected to the said outer cylinder so that the stirrer is placed in the junction of the tube (9) , the said outer cylinder (2) providing the suction mechanism to flow the water inside the cylinder containing capillary (12) to maintain the constant temperature bath.

Full Text

The present invention relates to a capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid. This invention will be useful for the determination of the Theological properties of the fluid, exhibiting Newtonian and non-Newtonian behaviour. BACKGROUND OF THE INVENTION Falling ball, or sphere, viscometers, rotation viscometers and capillary viscometers are known from prior art for determining the flow characteristics of fluid termed as viscosity. Falling sphere viscometers can determine the viscosity of only Newtonian fluids and their measurement procedures involve discontinuous method and the systems cannot be used under conditions involving high temperatures, high pressures and for the actual fluids used in manufacturing processes that invariably exhibit non-Newtonian behaviour. Rotational viscometer can measure non- Newtonian fluids, though, they fail when the test fluid tends to settle or solidify or have high solid matter content. Further with highly volatile fluids, an open surface negatively influences any measured results. Under processing conditions, the measured results generally depend upon the flow conditions. These results thus have some limitations with respect to using them for testing different substances. It is possible only to a limited degree and can be accomplished only by interfering with viscometer flow. Such a problem arises more prominently at flows under high pressure. The oscillation viscometers apparently do not involve any viscometer flow, though, with inertia-reaction forces and surrounding conditions these viscometers do not allow exact viscosity measurements. Thus, only relative values are determined. Besides an oscillation viscometer may not be suitable for fluids comprising sediments or containing solid matters. The capillary viscometer measure viscosity discontinuously. Viscosity measurement in such systems take place intermittently, as these viscometers involve cleaning, filling and tempering of a storage container. It could be done continuously in a by-pass-manner wherein a definite volume of test fluid flows along the test path with the help of a gear pump. The kowledge of the Theological behaviour and the determination of the Theological data are necessary in order to describe the flow characteristics of the fluid. The Theological behaviour can be characterised by using a proportionality relationship between the shear stress which is shear force extended on per unit area of the fluid element and to the negative of the local velocity gradient. A velocity gradient can thus be regarded as a driving force for momentum transport. The measurement of the viscosity of the fluid is generally done by rotating viscometer or by capillary viscometer. The rotational viscometer mainly falls into two categories: those where two concentric cylinders rotates relative to one another around a common axis; and those consisting of a cone of the large vertical angles 180° and plate whose plane is through the apex of the cone. But in all types the test fluid is sheared between the rotating parts. A concentric cylinder in which the experiments are performed can be formed by regarding a beaker as the outer cylinder, and placing a rotating inner cylinder concentrically within it. The conventional rotational viscometer has shown in figure-1 wherein, the test fluid (4) is kept in the outer cylinder (5), an inner cylinder (3) is connected with a motor (1) rotates in constant rotational speeds. The shearing rate for the fluid is monitored by the momentum sensor (2) connected between the motor (1) and the inner cylinder (3). The major drawbacks of this device is the application of the shear stress using a rotating device. It thus changes the original molecular stnjcture of the fluid, which is responsible for its Theological characteristics. The viscosity that is measured using such systems may not necessarily be the actual viscosity of the fluid. Besides, the fluids are normally not subjected to such conditions in real life situation under which the properties are determined using rotational viscometers. The Capillary viscometers are suitable for rheological measurement or studies of both Newtonian and non-Newtonian type of fluids. Figure (2) shows the capillary viscometer for measurement of non-Newtonian fluid wherein the die holding the block (2) is a channel for inserting the capillary inlet by means (3), the pressure difference is measured by the pressure sensor (4) and (5), the flow rate is determined by means (6). The major disadvantage of the device is the use of plunger. The system may not essentially be suitable for the compressive fluids. It may affect the flow and rheological characteristics of the fluid. These systems may give erroneous results for non-Newtonian fluids following two parameter models e.g. Bingham Plastic. These models have been found reasonably accurate for many fine suspensions and pastes. Reference may be made to US Patent no. 5331843, wherein a Capillary viscometer has been designed comprising a measuring cylinder having an axially movable piston. The measuring cylinder and the piston define a measuring space which communicate with a capillary tube and a differential pressure gauge. The pressure difference between the measuring space and a tested medium is registered and processed by a signal-processing unit, however, this device is not economical. Reference may be made to US Patent no. 6,428,488, wherein a Capillary viscometer has been designed comprising a Y connector and is suitable for measuring low shear rates . The main object of the present invention is to provide a capillary viscometer apparatus to determine the flow characteristic of Newtonian and non-Newtonian fluids which obviates the drawbacks as detailed above. In an object of the present invention is to provide a capillary viscometer apparatus which is simple to operate. Yet another object of the present invention is to provide a capillary viscometer apparatus which can measure rheological properties of both Newtonian and non- Newtonian fluids including fluids having suspensions and or exhibiting Bingham plastic behaviour. In another object of the present invention is to provide a capillary viscometer apparatus which can measure viscosity continuously and can simulate some essential features of the processes under which the fluid is subjected to. Yet another object of the present invention is to provide a capillary viscometer apparatus which can measure rheological properties under high-pressure flows and high temperature with some modifications. Novelty of the invention lies in the fabrication of a capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid which comprises an inner cylinder made of heat conducting materials, and an outer cylinder of capacity covered with an insulated sheet, the test fluid being kept in the inner cylinder connected with a manometer by means of capillary being surrounded by glass tube to monitor the pressure in the inner cylinder and the outer cylinder containing constant temperature water bath being maintained by a heater and being uniformly distributed by continuous stirring by means of a stirrer and its speed being controlled by a motor and one inlet of the capillary being connected to the bottom of the inner cylinder and outlet of the capillary being put to a beaker to determine the flow rate of the lost fluid and the capillary tube being put inside a cylinder containing constant temperature water bath by means of tube and the inlet of the tube being connected to the outer cylinder and the outlet being connected to the upper half of the cylinder containing capillary and inlet of the other tube being connected to the lower part of the cylinder containing capillary and outlet being connected to the outer cylinder in such a manner that the stirrer is placed in the junction of the tube and the outer cylinder providing the suction mechanism to flow the water inside the cylinder containing capillary to maintain the constant temperature bath. This viscometer can measure rheological properties over a wide range of shear rates and even under high-pressure flows and high temperature with some modifications. Accordingly the present invention provides a capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid which comprises an inner cylinder (1) made of heat conducting materials, and an outer cylinder (2) of capacity covered with an insulated sheet, the test fluid being kept in the said inner cylinder(l) which is being connected with a manometer (14) by means of capillary being surrounded by glass tube (7) to monitor the pressure in the inner cylinder(l), the said outer cylinder(2) containing constant temperature water bath being maintained by a heater (3) and being uniformly distributed by continuous stirring by means of a stirrer and its speed being controlled by a motor (5), one inlet of the said capillary (12) being connected to the bottom of the said inner cylinder (1), outlet of the said capillary being put to a beaker (13) to determine the flow rate of the lost fluid, the capillary tube being put inside a cylinder containing constant temperature water bath by means of tube (8)&(9) , the inlet of a tube (6) being connected to the said outer cylinder & the outlet (11) being connected to the upper half of the cylinder containing capillary (12), inlet of other tube (9) being connected to the lower part of the cylinder containing capillary (12) & outlet being connected to the said outer cylinder so that the stirrer is placed in the junction of the tube (9) , the said outer cylinder (2) providing the suction mechanism to flow the water inside the cylinder containing capillary (12) to maintain the constant temperature bath This viscometer can measure rheological properties over a wide range of shear rates and even under high-pressure flows and high temperature with some modifications. Accordingly the present invention provides a capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid which comprises an inner cylinder (1) made of heat conducting materials of capacity between 3 to 5 liters, and an outer cylinder (2) of capacity between 8 to 10 liters having covered with insulated sheet, the test fluid is kept in the inner cylinder(1) connected with a manometer (14) by means (7) to monitor the pressure in the inner cylinder(l) and the outer cylinder(2) contains constant temperature water bath maintaining by the heater (3) and uniformly distributed by continuous stirring by means of a stirrer and its speed is controlled by a motor (5), one inlet of the capillary (12) is connected to the bottom of the inner cylinder (1) and outlet of the capillary is put to a beaker (13) to determine the flow rate of the lost fluid, the capillary tube is put inside a cylinder containing constant temperature water bath by means of tube (8)&(9), the inlet of the tube (6) connected to the outer cylinder and the outlet (11) is connected to the upper half of the cylinder containing capillary (12), and inlet of the other tube (9) is connected to the lower part of the cylinder containing capillary (12) and outlet is connected to the outer cylinder in such a manner that the stirrer is placed in the junction of the tube (9) and the outer cylinder (2) to have the suction mechanism to flow the water inside the cylinder containing capillary (12) to maintain the constant temperature bath. In the embodiment of the present invention the capillary tube may be made of the Perspex glass and may have the length to diameter ratio in the range of between 200 to 300. In another embodiment of the present invention the temperature of the test fluid may be in the range between 30 to 100°C. In yet another embodiment of the present invention the the said device measures viscosity of Newtonian and non-Newtonian fluid for a wider range of shear rates DETAILED DESCRIPTION OF THE INVENTION In the present invention a measured volume of the test fluid was taken into a capillary viscometer comprising a 3-litre capacity inner cylinder made of copper (1) and an outer cylinder (2) covered with insulated sheet is used for keeping the test fluid in the inner cylinder while the outer cylinder contains a constant temperature water bath, the temperature of the water bath of the outer cylinder (2) is maintained by the heater (3) and uniformly distributed by continuous stirring by means of a stirrer and its speed is controlled by a motor (5), having checked all the joints and connections as perfectly air tight, the values connecting of means (7) the compressor to the inner cylinder (1) and the inner cylinder (1) to the manometer (14) were kept open completely, the other valve of the manometer (14) connecting to the atmosphere was closed, the compressor was then started, at a desired pressure of air acting over the test fluid(l). The test fluid is allowed to flow through the inlet of the capillary (12) which is connected to the bottom of the inner cylinder (1) and outlet of the capillary is put to a receptacle (13) to determine the flow rate of the test fluid using a time monitoring device, the Theological properties of these fluids were determined by inferring the relation between the shear stress and rate of shear indirectly from observations on pressure gradient and volumetric flow rate in a capillary tube viscometer, the capillary tube encapsulated in a cylinder containing constant temperature water bath by means of tube (8), (9), the inlet of the tube (6) connected to the outer cylinder and the outlet (11) is connected to the upper half of the cylinder containing capillary (11), and inlet of the other tube (9) is connected to the lower part of the cylinder containing capillary (12) and outlet is connected to the outer cylinder in such a manner that the stirrer is placed in the junction of the tube (9) and the outer cylinder (2) to have the Suction mechanism to flow the water inside the cylinder containing capillary (12) to maintain the constant temperature bath. A manometer (14) is connected to the inner cylinder by means (7) to measure the pressure. The shear stress and pseudo shear rate thus obtained were plotted for various fluids on log log paper, the consistency and flow behaviour index were calculated using equation: (EQUATION REMOVED) Where Dc is the diameter of the capillary, U is the length of the capillary, nP is the pressure gradient, U is the velocity of the fluid through capillary, k is the consistency index and n' is generalised flow behaviour index. The main object of the present invention is to provide a capillary viscometer apparatus to determine the flow characteristic of Newtonian and non-Newtonian fluids which obviates the drawbacks as detailed above. ADVANTAGES 1. The viscometer is simple to operate. It does not have many moving parts. 2. It can measure rheological properties of both Newtonian and non- Newtonian fluids including fluids having suspensions and or exhibiting Bingham plastic behaviour. 3. It measures viscosity continuously and can simulate some essential features of the processes under which the fluid is subjected to. 4. The viscosity can be measured under high-pressure flows and high temperature with some modifications. We claim 1. A capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid which comprises an inner cylinder (1) made of heat conducting materials, and an outer cylinder (2) of capacity covered with an insulated sheet, the test fluid being kept in the said inner cylinder(1) which is being connected with a manometer (14) by means of capillary being surrounded by glass tube (7) to monitor the pressure in the inner cylinder(1), the said outer cylinder(2) containing constant temperature water bath being maintained by a heater (3) and being uniformly distributed by continuous stirring by means of a stirrer and its speed being controlled by a motor (5), one inlet of the said capillary (12) being connected to the bottom of the said inner cylinder (1) , outlet of the said capillary being put to a beaker (13) to determine the flow rate of the lost fluid, the capillary tube being put inside a cylinder containing constant temperature water bath by means of tube (8)&(9), the inlet of a tube (6) being connected to the said outer cylinder & the outlet (11) being connected to the upper half of the cylinder containing capillary (12), inlet of other tube (9) being connected to the lower part of the cylinder containing capillary (12) & outlet being connected to the said outer cylinder so that the stirrer is placed in the junction of the tube (9) , the said outer cylinder (2) providing the suction mechanism to flow the water inside the cylinder containing capillary (12) to maintain the constant temperature bath. 2. A device as claimed in claim 1 wherein the capillary tube may be made of the Perspex glass and have the length to diameter ratio in the range of between 200 to 300. 3. A device as claimed in claim 1-2 wherein the temperature of the test fluid is in the range between 30 to 100°C. 4. A capillary viscometer device to determine the flow characteristics of Newtonian and non-Newtonian fluid as herein described with reference to Fig.3 of the drawings accompanying the specification.

Documents:

421-del-2004-Abstract-(01-03-2013).pdf

421-del-2004-Abstract-(15-11-2010).pdf

421-del-2004-abstract.pdf

421-del-2004-Claims-(01-03-2013).pdf

421-del-2004-Claims-(15-11-2010).pdf

421-del-2004-claims.pdf

421-del-2004-Correspondence Others-(01-03-2013).pdf

421-del-2004-Correspondence-Others-(15-11-2010).pdf

421-del-2004-correspondence-others.pdf

421-del-2004-correspondence-po.pdf

421-del-2004-Description (Complete)-(01-03-2013).pdf

421-del-2004-Description (Complete)-(15-11-2010).pdf

421-del-2004-description (complete).pdf

421-del-2004-drawings.pdf

421-del-2004-form-1.pdf

421-del-2004-form-18.pdf

421-del-2004-Form-2-(01-03-2013).pdf

421-del-2004-form-2.pdf

421-del-2004-Form-3-(15-11-2010).pdf

421-del-2004-form-3.pdf

421-del-2004-form-5.pdf