SU131089A1 - Capillary viscometer for rheological studies of high polymer materials - Google Patents

Description

The known devices, based on the principle of capillary viscometry and used to test the physicomechanical properties of rubber and rubber compounds, do not provide the possibility of obtaining the true shape of the rheological curve of the material under investigation because There are significant input effects, reaching 10-60% of the total displacement and, moreover, the flow in the channel is accompanied by wall sliding, the magnitude of which is very undefined.

In the described viscosity meter for rheological studies of high polymer rubber-like materials, these drawbacks are eliminated. For these purposes, the viscometer is equipped with a choke at the exit of the capillary.

The drawing shows a diagram of a capillary viscometer.

The viscometer has a thermostat 1, a working cylinder 2 with a plunger 3, a capillary 4, at the outlet of which there is a throttle 5. A lever mechanism consisting of lever 6 with weights 7 and a handle 8 is applied to create pressure in the material under investigation. their position on the lever 6, it is possible to vary the pressure in the chamber 9 within the wide limits. The determination of the rate of expiration of the material under investigation is made according to the indications of indicator 10, which is read at regular intervals of Burden. At high flow rates, a strain gauge displacement transducer is connected, consisting of a plate transducer and a threaded rod, with an angle of 120 °, a standard strain gauge amplifier and an oscilloscope. To eliminate the effect of entry, material testing is carried out in a differential manner, using a dual capillary tube. The processing of the resulting flow rate versus pressure curves makes it possible to eliminate input losses and to determine the true flow curve. To simplify the measurement of a working organ with a portion of the material under study, the plunger 3 is made composite; to replace the tool, it is enough to remove the weights from the lever 6, turn the handle 8 and lift the lever to the upper position in which it is held by the cam //, then remove the empty tool from the central socket of the thermostat 1 and insert it in its place another with a new portion of the material studied.

The test material (rubber or rubber mixture) is placed in chamber 9 and kept there for the time required for its nporpeBa (20-30 min). By turning the knob 8, the lever 6 with the weights 7 is lowered onto the plunger 5. In this case, the rate of flow of material through the capillary 4 is determined; choke 5 eliminates wall slippage from the capillary material. After conducting a series of tests with a long capillary, the latter is changed to a short capillary of the same diameter.

Subject invention

A capillary viscometer for rheological studies of high polymer materials, characterized in that, in order to avoid wall sliding during the flow of materials, it is equipped with a choke at the exit of the capillary.