SU502297A1 - Rotational visco-simulator - Google Patents

Description

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The invention relates to instruments for studying the rheological properties of heavy petroleum products (petroleum residues) and can be used in the refining industry.

A device is known for studying the rheological properties of highly viscous materials, consisting of cone-cone-type measuring surfaces, one of which is associated with an elastic element designed to compensate for the developed shear stress, an electric drive with a transmission box and a multi-viscosity index.

A disadvantage of the known instrument is that in the process of measuring the viscosity of oil. products that foam at high temperatures, a test product accumulates on the top of the measuring cones, which cannot flow back into the working cavity of the device due to the lack of space for the flow of the foamed mass into the cavity of the measuring cones.

The foam mass outside the working cavity creates an additional shear stress, which changes the measurement accuracy. Therefore, the known devices cannot be used for rheological studies of foaming petroleum products.

The aim of the invention is to improve the measurement accuracy by creating a cavity

for draining the foamed mass into the gap of the measuring cones.

For this, the inner cone of the rotational plastoviscimeter is biconical with a solid angle of an additional cone 60 °, and the outer rotating cone is connected to a rotating cylinder through the surface of a truncated cone, which forms a conical annular space with the surface of the inner upper cone.

Pa drawing shows a diagram of the proposed rotational plastoviscometer. The outer rotating cone 1 connects

through the surface of a truncated cone with a rotating cylinder 2 and lowered into an electric furnace 3. The internal cone of the device, having an additional top cone 4 with a solid angle of 60 °, is mounted in a cantilever in the case of a plastic viscometer by means of a rod 5 and internal radially resistant ball bearings 6 7, which, depending on the range of the measurement of the shear stress, is engaged with one of the load cells of the compensation system 8. The power meters are used as load cells converters with unified current output 20 ma

(according to GOST 14795-69).

The outer measuring cone 1 is driven by an electric drive 9 with an additional gearbox via a gear pair 10, which is attached to the housing of the viscometer and freely rotates around a vertical axis. The housing of the viscometer rests on the outer radial-resistant support 11 mounted on the frame of the device 12. The frame can move vertically in three racks 13. The drive has a built-in tachogenerator that generates a signal proportional to the number of revolutions of the electric motor in the range (1 - 0.8) 10. This signal used when automatically recording the flow curve on a two-coordinate recorder. An additional 10-speed gearbox with a range of 1 to 10 is used to extend the speed limit.

Automatic measurement and recording of temperature is performed by a KSP-4 multipoint electronic potentiometer 14. Temperature sensors are thermocouples 15, 16 and 17, located at the helix of the electric heating furnace, at the wall of the measuring glass and above the test product.

Control panel 18 serves to power all units and devices. It consists of switches and indicators, overcurrent breakers and interlocking devices.

The viscosity measurement process is carried out according to the constant strain rate method. When the inner cone 4 is stationary, the outer cone 1 rotates at a constant angular velocity. In this case, the voltage of the tachogenerator of the electric drive 9 is transmitted to write to the two-coordinate recording device 19. A torque, proportional to the effective viscosity, which occurs during the measurement, is transmitted to the cheek 7, then Depending on the measurement range of the shear stress, to one of the load cells of the compensation system 8, which compensates for this moment, very little (tens of microns) moving the cheeks 7. Strength measure It produces a constant current proportional to the measured force (viscosity). This current is measured with a pointer or a self-detecting milliammeter (secondary device) 20. For writing to a two-coordinate recorder, the voltage is removed from a resistance of 100 ohm, connected in series with the secondary device.

The scale of the secondary instrument is calibrated using calibration fluids based on the measurement range.

The outer cone 1 together with the lower part of the inner cone 4 forms a measuring surface of the cone-cone type. The annular space enclosed between the surface of the outer truncated cone and the surface of the upper inner

0 cone, serves to collect and quench the foamed mass formed during the testing of petroleum products prone to swelling. Foam thickening is achieved as a result of a decrease in the rate of upward flow of gases (diluted air, water vapor and light hydrocarbons) due to expansion of the annular cavity. The initial volume of the product is taken so (level b) that at the end of the test the residual product takes up the smallest amount

0 (level e). In the expanded state, the product volume reaches the level a.

The tangential force developed by the measuring surfaces (below level c) determines the magnitude of the measured viscosity. The shear stress developed between the upper inner cone and the truncated outer cone is insignificant, which is explained by the absence of a free liquid phase (except for stable foam) and a small gradient of shear rate in this cavity.

Claims (1)

Invention Formula A rotary viscometer for studying the rheological properties of highly viscous petroleum products (petroleum residues) foaming when heated, consisting of a cone-cone measuring device, an electric drive with an additional gearbox, a sensor, a viscosity recorder and a thermostat, characterized in that In order to improve measurement accuracy due to the flow of foamed mass into the cavity of the measuring cones, the internal cone of the rotational plastoviscometer is biconical with an additional cone solid angle of 60 °, and the external rotating cone is connected to the rotating cylinder through the surface of the truncated cone that forms a conical ring with the surface of the internal upper cone space.    ,,, v-, ....