SU1242759A1 - Coaxial-cylinder viscometer - Google Patents

Abstract

A rotational viscometer is described, which includes a nozzle mounted on a shaft, the other end of which is connected via a spring to the housing, a cell for the test substance, an electric drive, a resistive spring twist angle sensor and a circuit for converting the spring twist angle of the spring into a time interval. The described viscometer improves the accuracy of measurements and their speed. I il. (C sr) GO s: l

Description

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The invention relates to the measurement of the rheological characteristics of liquids and pastes, in particular in the production of thick-film microcircuits, can be used in the chemical industry.

The aim of the invention is to improve the accuracy and speed of the sensor.

. The drawing shows the functional-kinematic scheme of the device.

The circuit contains the motor I, the gearbox 2, the cuvette 3, the probe 4, the resistive torque sensor 5, the shaft 6, the measuring spring 7, the linear variable voltage driver 8, the comparison circuit 9, the limiter 10 and the trigger 1 one .

The rotor of the electric motor 1 is connected through the gearbox 2 to the cuvette 3, which is rotated. At one end of the shaft 6, a probe 4 is fixed, placed in the cuvette 3, and at the other end is a measuring spring 7, the second end of which is rigidly connected to the housing. The movable contact of the resistive sensor 5 is rigidly connected to the shaft 6 and electrically connected to one of the inputs of the comparison circuit 9, the second input of which is connected to the input of the linear variable voltage driver 8.

On the shaft 6 of rotation of the cuvette 3 there is fixed a movable contact of the generator 8 of a linearly varying voltage, and the angle of rotation of the movable contact is not limited. The frame of the voltage is fixed on the common housing. The outputs of the comparison circuit 9 and the limiter amplifier 10 are connected, respectively, to the S- and R-inputs of the trigger 11.

The device works as follows.

The cuvette 3 from the electric drive is driven into rotation and, due to the presence of friction forces between the particles in the sample under study, shaft 6 is twisted: increasing the output resistance of the pe3HCT iBHoro sensor 5 in proportion to the shear stress.

The former 8 is made in the form of a potentiometer without limiting the angle of rotation of the sliding contact, which is rigidly connected to the rotation shaft 6 of the cuvette 3. The current value of the output resistance of the potentiometer is measured.

2427592

It is time and time proportional to the speed of rotation of the cuvette 3.

Voltages from the resistive sensor 5 and the imager 8 are applied to

5 inputs of comparison circuit 9. At the end of the inter-shaft time T, these voltages become equal, and the immediate: circuit is triggered.

If the nominal values of potentiometers 10 and 5 and 8 are chosen equal, and connected to the same power source E ", then the value of the time interval from the beginning of the formation of the linearly varying voltage 15 nor until the moment of operation of the circuit

compared in proportion to the viscosity of the test substance itself.

The beginning of the moment of formation of the linearly varying voltage is fixed by the amplifier-limiter, the output impulse of which sets the trigger via the R input to a single state. At the moment of triggering the comparison circuit, the trigger returns

25 to the initial state due to the pulse at the S-input from the output of the circuit is compared to. neither

After completing one revolution of the shaft of rotation of the cuvette, the circuit compared to .JQ neither and the limiting amplifier return to the previous state.

Claims (1)

Invention Formula A rotational viscometer containing a measuring probe fixed at one end of the shaft, a cuvette for the test substance, a twisting spring, an electric actuator and a resistive sensor of the rotating spring of the spring, and the second end of the shaft is connected to the body The cuvette, in which the probe is placed, is connected to an electric actuator, characterized in that, in order to increase the accuracy and speed of the sensor, it is equipped with a comparison circuit, a limiting amplifier, a trigger and a linear-variable driver. voltage in R ™ £); e potentiometer with circular rotation sliding contact which kinematically connected with the shaft of rotation of the cuvette, the former forcing a linearly varying voltage attached to the body, one of 50 5: 5 the outputs of the resistive sensor are connected to the Earth bus, and the second is connected to a single one. inputs of the comparison circuit, the second input of which is connected to 3 12427594 The linear-ramp output from the R-input of the trigger, and the S-input of the trigger voltage and the input of the amplifier — is connected to the output of the comparator circuit, the output of which is connected. Y // Y / X / . 7 X MfE m Kyubet Redu gt70r 2 -f W Editor A. Shandor Compiled by V.Voschankin Tehred O.Gortvay Order 3691/38 Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Corrector S.Cherni