SU1305646A1 - Liquid level regulator - Google Patents

Abstract

The invention relates to automatic level control of a liquid and can be used to measure and control the level of a liquid, both constant and variable density, which is in a tank under atmospheric pressure. The purpose of the invention is to expand the scope of application of the regulator and increase the accuracy of work when the density of a liquid changes. For this, the liquid level regulator contains pressure sensors 1 and 2 located in tank 3 at different depths, adder 4, subtraction unit 5, dividing unit 6, regulator 7 with setting level 8 and actuator 9 with actuator installed in pipeline 10 plum. 1 il. from sd o5 4 05

Description

The invention relates to automatic level control of a liquid and can be used to measure 11 and to adjust the level of a liquid both constant and variable in a reservoir at atmospheric pressure.

The purpose of the invention is to expand the scope of application of the regulator and increase the accuracy of operation when the density of a liquid changes.

The drawing shows a block diagram of the regulator.

The fluid level regulator contains pressure sensors 1 and 2 located in tank 3 at different depths, adder 4, subtraction unit 5, dividing unit 6, regulator 7 with setpoint level 8 and actuator 9 with actuator installed in the pipeline 10 draining the liquid from the tank.

The pressure sensed by immersing a liquid at different depths by pressure sensors is

PI h fgi PI,

h.

, h, is the depth of the dates

chikov j

p is the density of the liquid; g is the acceleration of the earth's t goteni.

Consider two control systems that get

Р, -Р (.h, -h) f g-, Р, + Р2 (h, + h) f g.

From the first equation can be found.

what

r-p

12

  one

(h, -h) g

and, substituting this expression for the peer equation, get

h + h

P, + P2 (R.-Pr)

.

or

  ()

p, + p,

p p

m g

If it is accepted that the total immersion depth of the sensors is equal to the value of the regulated liquid level, i.e. , the difference is denoted by L, then we get that

Ny

P, + P,

R - G /

ten

f5

20

25

thirty

35

40

45

50

This expression is the methodological basis for measuring and regulating fluid levels.

The regulator works as follows.

The transducer signals of sensors 1 and 2, corresponding to the pressure of the liquid in the tank 3 at the depth of their immersion, arrive at the corresponding inputs of the adder 4 and the subtraction unit 5, and from their outputs the signals arrive at the division unit 6, i.e. the ratio of the sum of pressures to their difference is calculated. The output signal of block 6 as a signal. The parameter is fed to the input of regulator 7 and is a signal proportional to the regulated liquid level, since the coefficient h h is a constant value for a particular implementation of the regulator and is studied in the setting unit 8. The reference signal is selected such that so that at a given level of fluid in tank 3, the signal at the output of regulator 7 was absent.

This regulator can be implemented on the element base of both pneumatic automation and electrical automation.

Thus, the regulator does not react to a change in the density of the liquid, and a change in the level of the liquid leads to the formation of a control signal by the actuating element 9. The controller can operate with a liquid with both constant and variable density, which expands the possibility of using the regulator to the regions where the density of the fluid cannot be maintained or where a fluid with variable density is required.

55

Claims (1)

Invention Formula The fluid level regulator containing those located in the reservoir on 313056464 two pressure sensors, fluid density, are entered into it, an adder connected by inputs to a pressure unit and a subtraction unit, pressure sensor inputs from the corresponding sensors, and pressure sensors in series, and an output unit level, regulator, actuator - to the first input of the unit pressure and the actuating element, installed, connected by the second input to your c. pipeline drain liquid outlet of the adder, and the output - to the second from. The reservoir is distinguished by the {{р) input of the regulator, moreover, in order to expand the installation depth of the sensors in the pressure range of the regulator and THROTHING, it is equal to the level of the controlled working fluid at varying degrees.