SU476817A1 - Capillary Visograph - Google Patents

Description

(54) CAPILLARY WISCOGRAPH

Automatic cagsiplity vista; intended for research in the core; properties of disperse and popim. these things., characterized by a flow curve, pr: p :, Yellai a dependence of the velocity of and their lives on for example: /; an shift in a wide, cypagon their ziachenl: {shear pressure shift 10- EiO shear rate Yu - Yu).

In the known auto capillary viscous filters, for one experience of viscosity dependence on the pressure in the capillary and shear rate, a calibrated spring is applied, which dissipates the pressure on the material placed in the chamber and in the course of the tests. most providing a variable flow rate from the capillary.

The displacement of the plunger, extruding the material from the chamber, is recorded on the drum in a time dependence, from which then the shear stress, shear rate and viscosity are calculated. However, the recording of measurement results obtained on the drum of the instrument requires decoding-graphic differentiation and logarithm

to bring the results to mind, for analysis, to a graph view of the shear rate from the shear stress with in: by using the headquarters double rhymmy.

An instrument’s abundance is manual i.raxtraining recording speeds depending on the type of recorded curve, which is inconvenient, and with rapidly changing speeds, ke is always possible.

The transfer capillary viscograph makes it possible to measure with high accuracy and simultaneously record the flow curves without additional calculations and in print. oarithmic scale.

This is achieved by introducing into the proposed Visograph a raster sensor of discrete displacements of the plunger associated with a displacement velocity meter and counting by an iHKOb transducer code - voltage, ir mountains connected to a two-coordinate recorder of the flow curve of the material under study.

The drawing shows a functional diagram of the proposed visograph.

An automatic capillary scanner contains a load device in the form of a spring 1 that transmits pressure to plunger 2, which enters chamber 3 connected by a cf capillary 4. A discrete displacement 5 is connected to the plunger, for example a raster sensor consisting of a movable 6 and a fixed 7 plates, an illuminator 8 and a photo of the receiver 9. The output of the sensor 5 is connected to a pressure gauge consisting of a series-connected counter 10, a digital-to-analog converter 11, a pressure logarithm 12; to a speed meter consisting of a scheme of conjunction 13, counter 14, a digital-analog converter mantissa 15, a logarifmator 16 speed, a controlled generator 17, a decoupling and control circuit 18, a digital-analog converter characteristic 19 and an adder 20. Circuit 13, a speed meter 14 A digital-to-analog converter 15, a logarithm 16 are connected in series and form a mantissa receiving circuit. A speed meter counter 14, an evaluation and control circuit 18, a controlled oscillator 17 and a conjunction circuit 13 form a feedback circuit. The controlled generator 17 is also electrically connected to the counter 14 of the speed meter and the evaluation and control circuit 18. This connection is auxiliary. The digital-to-analog converter 1E and the evaluation and control circuit 18 constitute the circuit for forming the characteristic of the velocity logarithm. With this circuit, with the output of a digital-to-analog converter 19, and with the circuit of receiving the mantissa, with the output of a logarithmator of 16 speed, the adder 2O is electrically connected. The output of the adder 20 and the output of the logarithm 12 of the pressure gauge are connected to the inputs Y and X of the two-coordinate register 21.

The device works as follows. The spring 1, which is in a compressed state with the beginning, expresses and pushes the plunger 2, squeezing out; loading the test product from chamber 3 through a calibrated cylindrical capillary 4. As the spring depresses, the pressure drop in the capillary where the product flows, and the speed of movement of the plunger 2 accordingly decreases.

The measured values of voltage and shear rate are determined respectively by the magnitude of the spring expansion from its initial position and the speed of movement of the plunger.

To determine these values, a sensor 5 of discrete displacements is coupled to the plunger, which produces electrical pulses, the quantity, the tracking frequency and the duration of which are determined by the sensor increments of the sensor and the speed of movement of the plunger. Pulses from the output of the discrete displacement sensor are fed to the pressure gauge and the speed meter.

In the pressure gauge, the counter 10 counts the number of pulses and forms the current code value of the amount of movement of the plunger. Using a digital-to-analog converter and a pressure gauge, the code is transformed into a proportional pressure, and then, using a device with a logarithmic amplitude characteristic — a pressure logarithm — into a voltage proportional to the logarithm of the pressure exerted by the spring on the product.

The pulse signal from the output of the discrete displacement sensor is fed to the input of the conjunction circuit 13, which also receives the time interval signal from the controlled oscillator 17. The resulting burst is counted by the counter 14.

The code value obtained in this counter is npeo6pa3yeJ4:; H to the corresponding voltage in the digital-to-analog converter of the mantissa 15, and then, using a device with a logarithmic amplitude characteristic - the speed logarithmator 16 - to a voltage proportional to the mantissa of the velocity of the logarithm of the speed 16, which is proportional to the mantisse of the speed of the logarithm, 16

After transmitting the code to the digital-to-analog converter, the counter 14 is set to zero by the signal of the controlled oscillator 17.

The time interval may be by the sensor of discrete movements. In this case, the pulses produced by the controlled generator will be counted & g and the counter will record the time of the plunger movement by the discrete step of the sensor, i.e. the reciprocal of velocity.

The transition from one measurement range to another is carried out automatically by changing the time interval emitted by the control. generator 17. The transition signal to generator 17 is supplied from a control circuit evaluating the code value obtained in the counter to the measurement interval.

If the value turns out to be smaller or larger than intended, a signal is sent to the controlled generator to change the time interval in the required direction. At the same time, to take into account the change in the measurement range, a code signal is fed from the evaluation and control circuit to the digital-to-analog converter

The current voltage on the adder is 2 O. In the adder, the sum of the voltages corresponding to the characteristics and the mantissa of the logarithm of the velocity obtained in the logarithm 16 is made.

Electrical signals from the logarithm 12 of the pressure gauge and the adder 20 are received respectively at the inputs of the X and Y coordinates of the two-coordinate recorder 21 which, as the material under study expresses, records the dependence of the logarithm of the plunger displacement speed (flow rate) on the pressure in the chamber or, taking into account the installed capillary, the velocity shift from shear stress, i.e. flow curve.

Claims (1)

Invention Formula A capillary visograph, containing a loading device in the form of a precompressed spring, plunger, capillary, a pressure and flow recording system, a two-coordinate recorder, characterized in that, in order to improve the measurement accuracy, it is equipped with a raster sensor of discrete displacement of the plunger connected to the meter Scorch: displacements and a counter with a code-voltage transducer, which, in turn, are connected to a two-coordinate recorder of the flow curve of the material under study.