SU1383145A1 - Device or measuring kinematic viscosity - Google Patents

Description

(21) 4172412 / 31-25

(22) 11/25/86

(46) 03/23/88. Bul ( eleven

(71) Lviv Polytechnic Institute. Lenin Komsomol

(72) E.P.Pistun, A.B.Krykh and M.P.Kulik

(53) 532.137 (088.8)

(56) Patent of France 1,278,309, cl. G 01 N 11/08, 1981.

Patent GDR No. 68392, cl. G 01 N 11/08, 1978.

(54) DEVICE FOR MEASURING KINEMATIC VISCOSITY

(57) The invention relates to instrumentation engineering, in particular to capillary viscometry,

and can be used in chemical, petrochemical and other industries.

indices in the analysis of liquid mixtures by kinematic viscosity. The aim of the invention is to improve the accuracy of kinematic viscosity measurements. This is achieved by the fact that the device implements the measurement of pressure drops on turbulent and laminar throttles, as well as obtaining their algebraic sum with the help of a spool valve, recognizing these pressure drops by changing the length of the capillary at a fixed value of the flow rate of the controlled medium, and indicating the displacement of the output medium the shaft of the power cylinder corresponding to the measured value of the kinematic viscosity. 1 il.

i

(L

with

CX) 00

four

sd

The invention relates to instrumentation engineering, in particular to capillary viscometry, and can be used in chemical, petrochemical, and other industries in the analysis of liquid mixtures by kinematic viscosity.

The aim of the invention is to improve the accuracy of kinematic viscosity measurements.

The drawing is a schematic diagram of the proposed device for measuring kinematic viscosity.

The diagram shows a constant flow setting device 1, a hollow cylinder 2 in which diaphragm 3 is rigidly fixed and piston 4 moving with screw grooves on the side surface, spool valve 5 with plunger 6, with movable bellows bottoms at both ends of which are rigidly rods 7 and 8 9 and 10, as well as a two-sided power cylinder 11 with a piston 12 and two output shafts 13 and 14 and a displacement indicator 15 on a shaft 14. The output shaft 13 of the power cylinder is connected to the piston 4, and the cylinder itself is connected to the output slots m of directional control valves. The pressure difference across the diaphragm enters the cavity delimited by the pulse chambers with the bellows 10, and the pressure differential across the variable-length capillary enters the hollow delimited by the bellows 9 with the bellows 9. In relation to the valve 6 of the hydraulic distributor 5, the indicated pressure differences are included opposite.

A device for measuring kinematic viscosity operates as follows.

The test medium in constant flow mode by means of setting device 1 is pumped through successively connected turbulent choke-diaphragm 3 and laminar choke-capillary of variable length, formed by cylinder 2 and piston 4 with helical grooves on the lateral surface. On the measuring elements, a pressure difference dR, and LR is formed, determined according to the pressure

L.RT

LR,, || ifU K, Ql,

where & P is the pressure drop across the turbulent choke; iP is the pressure drop across the laminar choke; p, | c - density and dynamic

medium viscosity;

f is the cross-sectional area of the diaphragm; E is the consumption coefficient; 1, R - length and internal radius

capillary;

Q is the flow rate of the controlled medium; K, Cd - constant coefficients.

These pressure drops enter the impulse chambers and move in the appropriate direction by means of bellows and rods rigidly connecting the moving bottoms of the bellows with: the plunger, the plunger 6 itself. After this, the plunger controls the flow of hydraulic fluid entering the two-sided power cylinder 11 which moves the piston 4, thereby changing the length of the capillary. The plunger 6 in the spool valve is moved until the pressure LR is equal to the pressure й-Rd. Then

Apt & p. From where

KL

 I v /

n

R; Q

those. at the time of equality of pressure drops, the capillary length equalizing the pressure drop across the diaphragm is inversely proportional to the kinematic viscosity of the medium under study (here | U / p). In the process of moving the plunger 6 and the corresponding movement of the output shaft of the power cylinder 11, the indicator 15 located on the shaft 14 of the power cylinder indicates the measured value of the kinematic viscosity on a scale of displacements.

Thus, the device measures the pressure drop across the turbulent and. laminar throttles, as well as obtaining their algebraic sum with the help of a specially adapted spool valve, equalizing these pressure drops by changing the length of the capillary at a fixed value of the flow rate controlled

dyes, as well as an indication of the movement of the output shaft of the power cylinder, corresponding to the measured value of the kinematic viscosity,

Claims (1)

Invention Formula A device for measuring the kinematic viscosity of a fluid, containing a constant flow setting device, a capillary p of variable length, made in the form of a cylinder and a piston moving in it with helical grooves on the lateral surface, a turbulent choke-diaphragm, differential pressure transducers connected to capillaries ru and throttle diaphragm, as well as the mechanism for changing the length of the capillary, to which the differential-metric converters are connected, In order to improve measurement accuracy, the differential pressure transducers are made in the form of a spool valve, both ends of the plunger are rigidly connected to movable bellows bottoms, which delimit the cavities between the body of the gold valve and the ends of the plunger on the impulse chambers, to which the corresponding chambers are connected. the diaphragm and capillary of variable length, and the mechanism for changing the length of the capillary is connected to the output slots of the hydraulic distributor A two-way power cylinder, one shaft of which is connected to the piston, and a movement indicator is placed on the other.