SU958910A1 - Viscometer - Google Patents

Description

- (54) VISCOSIMETER

one

The invention relates to the automatic control of the viscosity of various media and can be used in systems for the automatic control of technological parameters.

A rotational viscometer is known that contains a measuring micromachine made in the form of a series-connected generator and a motor with a resistor, on the shaft of which the measuring cylinder is fixed; a secondary device equipped with a second micromachine, made similar to the first one, the generator of the first and second micromachine being switched on according to the compensation circuit 1.

The disadvantages of this viscometer are low accuracy of viscosity measurement, low reliability, difficulty of using in systems of automatic viscosity control.

A rotational viscose meter is also known. It contains a two-phase asynchronous motor as a sensor and a bridge measurement circuit formed by a secondary winding of a transformer with a midpoint and two shoulders; in the measuring bridge circuit, two adjacent arms are formed by windings of a two-phase motor opposite adjacent shoulders - capacitors and the total supply voltage of the measuring bridge and the sensor motor is connected to one diagonal of the bridge to the second diagonal of which the imbalance indicator 2 is connected.

This technical solution also has a low viscosity measurement accuracy.

The closest technical solution to the invention is an automatic viscometer for studying melts containing a working member placed in a test liquid in a rotating cylinder, an angle sensor, an amplifier, a motor, a potentiometer and an executive motor, while the executive motor is mechanically connected to the working member and an angle sensor, the output of the angle sensor through an amplifier is connected to the input of the amplifier, the rotor of which is mechanically connected to the engine of a potentiometer, which is connected to the input having a full engine When the viscosity of the test fluid changes, which is in the cylinder, rotating at a certain speed, the working member begins to turn. This rotation is measured by an angle sensor, an amplifying signal proportional to the angle of rotation, is fed to the engine, which moves the potentiometer slider until the rotation of the actuator caused by this movement compensates for the rotation of the tool. The voltage taken from the engine of the potentiometer is proportional to the viscosity of the liquid 3. However, the accuracy of measuring the viscosity of this automatic viscometer is low due to disturbances created by the rotation of the cylinder with the liquid. The aim of the invention is to increase the accuracy of viscosity measurement. The goal is achieved by the fact that an automatic viscometer containing a working body, a rotating cylinder, an angle sensor, an amplifier and an executive motor mechanically connected to the working body and an angle sensor are additionally introduced a comparison unit, a reference signal source, a differentiator, a module for selecting a module, a threshold device, a key and a memory cell, the angle sensor output being connected to the first input of the comparator unit, the second input of which is connected to the output of the reference signal source, and the output of the comparing unit with the amplifier input, the output of which is connected to the input of the executive motor; the output of the comparator unit is connected to the control input of the key and the input of the differentiator, the output of which is connected to the signal input through serially connected module of the module and the threshold input; the entrance of the memory cell. The drawing shows a structural diagram of an automatic viscometer. The following notation is taken: x (t) is the error signal; iCt) - input effect; ) -signal from the angle sensor; ) - pulse signal from the output of the key m (.0 memorized value of the signal xnt). The scheme includes the working body 1, the test medium 2, into which the working body 1 is placed, the angle sensor 3, the input of which is connected to the working body 1, the amplifier 3, the executive motor 5, whose input is connected to the amplifier 4, the comparison unit 6, the output connected to the input of the amplifier 4, and the input connected to the sensor angle ZL, the source of the reference signal 7, which is connected to the comparison unit 6, the differentiator 8, connected to the output of the comparison unit 6, the allocation unit module 9, connected to the output of the differentiator 8,. | a threshold device 10 connected to the allocation unit of module 9, a key 11 connected to the output of the thresholds of the device 10 and to the output of the comparison unit 6, a memory cell 12 connected to the output of the key 11. The automatic viscometer works as follows. The signal taken from the angle sensor 3 is compared on the comparison unit 6 with the input action g (t) and the error signal x (t) is formed equal to X (t) Y (t) - g (t). The amplified signal x (t) is applied to the executive motor 5, which, by moving, changes the signal y () so as to bring it closer to the input influence g (t). If the input action is a step function I (t), then after the end the transition process (i.e., at x (t). where x (t) is the derivative of the error signal) the error signal is determined by the mechanical resistance of rotation of the working element 1, since this closed system has first-order astatism (one integrator). It is known that the error in this case can be written in the form, X (t) MH KM - active resistance of the engine core winding; Km - engine electromechanical coefficient; Ku-gain amplifier; MH is the mechanical moment of resistance. Since MH is directly proportional to the viscosity of the medium under study 2, the error signal x (t) under the condition x (t) - О carries information about the viscosity of the medium under investigation. To obtain this information, the signal x (t) is differentiated by x (t), rectified in block 9 modulo module (x (t)) and at the time when it becomes less than a certain value, threshold device 10 is triggered. This opens key 11 and the cell of memory 12 receives the error signal Hz (1), which carries information about viscosity. Then, the step function of the opposite sign g (t) l (t) arrives at the system input. / x (t) /. and the key 11 is closed. Until the next point in time, when The condition / x (t) / 6, cell 12 remembers the previous value of x (t). Thus, with an appropriate choice of the frequency of the sign change g (t) l (t), as well as the magnitude of this jump (so as not to develop more the speed of movement of the working body 1 and do not make disturbances

Claims (1)

Claim A viscometer containing a working body, a rotating cylinder, an angle sensor, an amplifier and an actuator mechanically connected to the working body and an angle sensor, characterized in that, in order to increase the accuracy of measuring viscosity, a comparison unit, a reference signal source, a differentiator are additionally introduced into it , a module allocation unit, a threshold device, a key and a memory cell, the output of the angle sensor connected to the first input of the comparison unit, the second input of which is connected to the output of the reference signal source, and the output is Comparison is connected to the input of the amplifier, the output of which is connected to the input of the actuator, while the output of the comparison unit is connected to the control input of the key and the input of the differentiator, the output of which is connected through a series-connected module selection unit and a threshold device to the signal input of the key, the output of which is connected with the input of the memory cell. Yu