RU211681U1 - CAPILLARY CELL OF LIQUID VISCOMETER - Google Patents

Abstract

The utility model relates to the technique of measuring the viscosity of liquids. The measuring setup is a Mariotte vessel filled with the investigated liquid, into the upper opening of which a glass tube is inserted through a rubber seal, which allows maintaining a constant pressure drop at the ends of the capillary. In the lower part there is a hole into which a capillary cell is inserted through a rubber seal having the shape of a truncated cone, in which coaxial holes of different sections are cut out on both sides. A capillary tube with an inner diameter d and a length l is tightly inserted into one of a smaller diameter. From the other end is inserted, also tightly, a mini-faucet, the inner diameter of which is D>> d so that there is no pressure drop inside the mini-faucet. The curved shape of the mini-faucet spout allows the liquid to drain in a controlled manner without loss into the receiving vessel. The outflow of liquid occurs under the action of a pressure drop at the ends of the capillary with a value of Δρ=ρgh. By measuring the volume of the leaked liquid and the outflow time, depending on h and d, the viscosity coefficient of the investigated liquid is calculated using the Poiseuille formula. The technical result is the convenience, simplicity and reliability of the design of the capillary cell, which makes it possible to avoid losses of the outflowing liquid, which makes it possible to increase the accuracy of measurements.

Description

A utility model (PM) refers to a technique for measuring the viscosity of liquids.

Capillary liquid viscometers are known (RU No. 19167 U1, publ. 10.08.2001, bull. No. 22), (RU No. 75745 U1, publ. 20.08.2008, bull. No. 23). Their common disadvantage is the complexity of the devices, the low accuracy of the results obtained.

Closest to the claimed PM is a viscometer consisting of a horizontal capillary cell, fixed in the lower part of the side wall of the Mariotte vessel. The liquid fills the Mariotte vessel, the design of which allows fixing the pressure difference at the ends of the capillary tube, and can flow through it. During the measurement, the stopper that closes the capillary tube is removed, the volume of the leaked liquid and the leakage time are measured depending on the pressure drop at the ends of the capillary. The neck of the vessel is tightly closed with a rubber stopper with a special tube inserted into it, the position of the lower end of which relative to the capillary regulates the pressure. The viscosity coefficient of a liquid is calculated using the Poiseuille formula (Laboratory workshop on general physics [Text]: textbook in 2 volumes. Vol. 1: Thermodynamics and molecular physics. 2nd ed., Rev. - 292 p. / Gladun A.D. , Aleksandrov D.A., Igoshin F.F. and others, edited by A.D. Gladun, Moscow, Moscow Institute of Physics and Technology, 2007, pp. 140-148, ISBN 5-7417-0206-6).

The disadvantage of this viscometer is the imperfection of the device of the capillary assembly, which makes it difficult to measure, can lead to the loss of the measured amount of liquid, and hence the measurement accuracy.

The objective of the utility model is to improve the capillary cell, leading to convenience, simplification and higher reliability and accuracy of measurements.

The solution of the problem is achieved by the fact that the measuring part of the viscometer is made in the form of a separate unit, called the capillary cell.

In FIG. 1 shows a general view of the viscometer, consisting of a Mariotte vessel filled with the liquid under study, into which a glass tube 1 is inserted through a rubber seal, the lower end of which is above the capillary 2 by the value h, which, together with the tap 3, forms a single unit - the capillary cell. The test liquid flows out of the vessel through an open tap into beaker 4.

In FIG. 2 shows a single capillary cell assembly.

In FIG. 3 its image in section, where 2 is a capillary with an internal diameter d calibrated, 5 is a rubber seal having the shape of a truncated cone, in which coaxial holes of different sections are cut out on both sides. A capillary tube with an inner diameter d and a length l is tightly inserted into one of a smaller diameter. It is possible to expand the range of measured values of the viscosity of the investigated liquid by changing the value of d. From the other end is inserted, also tightly, tap 3, the inner diameter of which is D>>d so that there is no pressure loss of the flowing fluid in the tap, and the capillary partially enters it. The range of values of the viscosity coefficient can be expanded by selecting different values of the capillary diameter. The shape of the spout of the tap is such that it allows the liquid to drain in a controlled manner without loss into the receiving vessel (beaker 4, in Fig. 1).

The outflow of liquid occurs under the action of a pressure drop at the ends of the capillary with a value of Δρ=ρgh. By measuring the volume of the leaked liquid and the outflow time depending on h and d, the viscosity coefficient of the investigated liquid can be calculated using the Poiseuille formula.

The technical result is the convenience, simplicity and reliability of the design, which makes it possible to avoid losses of the outflowing liquid, which makes it possible to increase the accuracy of measurements.

Claims (1)

A capillary cell for a liquid viscometer, characterized in that it consists of a rubber seal having the shape of a truncated cone, in which coaxial holes of different sections are cut on both sides, a capillary tube with an inner diameter d of length l is tightly inserted into one of them, of a smaller diameter, and from the other end, a stopcock is tightly inserted, the inner diameter of which is D>>d, while the capillary tube partially enters the stopcock.

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