SU1236346A1 - Method of measuring viscosity - Google Patents

Abstract

A method is described for measuring viscosity by damping a fluid with a rotating body and measuring the time interval in which the body rotates at a constant angular velocity, balances the moment of viscous friction and measures the twisting time of the elastic element before balancing in viscous friction, and the time interval is quantized by pulses with a given frequency. 1 hp f-ly, 1 ill. Nd SLE O CO i4 & O5

Description

"

The invention relates to methods for measuring viscosity with rotary instruments and can be used to measure fluids, in particular for plastics, fuels and lubricants, lacquers and food products.

The purpose of the invention is to improve the measurement accuracy and enhance functional capabilities,

The drawing schematically shows a device for implementing the method

The method is carried out as follows.

A liquid 2 is placed in the measuring organ 1 of the viscometer, the viscosity of which is to be measured. The rotation from the drive shaft 3 is transmitted through the elastic element 4 to the shaft 5 of the measuring body, rotating in the rolling bearings 6. A moment arises on the shaft 5 of the measuring body, due to the action of tangential stresses of the deformable fluid on the measuring surface of the body, and the spring 4 begins to twist, as a result of which the measuring body 5 runs behind the drive shaft 3.

When balancing the moment in the viscous friction of the liquid 2 by the moment of the spring 4, its twisting stops and the shafts 3 and 5 rotate displaced relative to each other by the angle of twist of the spring 4 proportional to the moment of the viscous friction. Since the shafts 3 and 5, connected by the spring 4, rotate, for each rotation, the spring twist angle is swept relative to the viscometer body at the speed Bpalqe of the measuring body,

The viscosity of a fluid is determined by the following relationship:

- “J.

(one)

where R is the measuring constant

bodies;

M is the torque; uJ is the angular rotational speed: The twisting moment balanced by the drum is determined by

M

WITH,

(2)

Where

eL spring twist angle; C - spring stiffness; Substituting (2) into (1), we obtain

4i3

(3)

but it is known that t-s.

(four)

where t is the sweep time of the angle of rotation of the spring relative to the body, which occurs with

speed a)

Consequently, the substrates (4) and (3) we get:

P R-C t.

Taking into account that R and C are constant for an instrument with a given spring and a measuring body, the viscosity of the fluid, measured with a rotating body by balancing the moment of viscous friction with that of an elastic element, is proportional to the sweep angle of the elastic element occurring the rotation speed of the measuring body,

35

AP

Formula invented

t "A method for measuring the viscosity of a fluid, based on the deformation of a fluid by a rotating measuring body and measuring the time interval, characterized in that, in order to increase the accuracy and

(extensions of functionality, deformation of the fluid are carried out at a constant angular velocity, balance the moment in the viscous friction of the fluid by twisting the elastic element of the measuring body and measure the time interval equal to the time of rotation of the angle through which the elastic element of the measuring body is twisted.

2. The method according to claim 1, characterized in that, in order to obtain a measurable quantity, directly, in units of viscosity, is measured -. time interval is quantized by pulse-tti., the frequency of which is chosen from the condition

 : mC R,

where w is the scaling factor;

With the stiffness of the elastic element;

R is the constant of the measuring body.

Compiled by V.Vashchankin Editor N.Dankulnch Techred I. Veres Proofreader, T.Kolb

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 VINILI State Committee of the USSR

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (2)

Claim 1 “A method of measuring fluid viscosity, based on the deformation of a fluid by a rotating measuring body and measuring the time interval, characterized in that, in order to improve accuracy and expand the functionality, the fluid is deformed at a constant angular velocity, balance the moment of viscous friction of the fluid with the moment of twisting of the elastic element measuring body and measure the time interval equal to the time of rotation of the angle by which the elastic element of the measuring body twisted. 2. The method according to claim 1, characterized in that, in order to obtain the measured value directly in units of viscosity, the measured time interval is quantized by pulses, the frequency of which is selected from the condition £ = u · C · R, where w is the scaling factor; C is the stiffness of the elastic element; R is the constant of the measuring body.