SU1307258A1 - Device for checking pressure - Google Patents

Abstract

The invention may be used. It is designed to indirectly control pressure in various parts of the coal sump and turbo compressor stations. The purpose of the invention is to increase accuracy and reliability. The device contains a source of fluid pressure 1, a pressure stabilizer 2 providing a predetermined constant pressure, a regulator 3, a flow rate, a channel 4, nozzles 5, a linear displacement sensor 6, a computing unit 7, a pressure setting unit 8, a flow setting unit 9, a geodetic setting unit 10; heights or differential and indicator 11, the introduction of new elements and the formation of new connections between the elements of the device provides a constant flow at the output of the flow controller 3. The linear movement of the locking element of the regulator 3 is detected by the linear movement sensor 6 connected to the input of the computing unit 7, which performs calculations based on the dependences shown. 2 Il. with S ate with -sj ate 00

Description

11307258

This invention relates to the control

pressure and can be used to indirectly control pressure in environments characterized by significant vibrations, vibrations, siltation or high temperature, for example, in different parts of the coal sump or turbo compressor station.

The aim of the invention is to increase accuracy and reliability.

Figure 1 shows the functional diagram of the device; Fig 2 is a diagram of a computing unit.

The device contains a source of pressure 1 auxiliary liquid 1, a stabilizer 2 pressure, providing at the outlet a predetermined constant pressure P const. It is hydraulicallyAt the entrance to channel 4

the pressure P const, the dock) is placed in the control, characterized by d 5 (the superscript is a pointer value, and the value is electric. Under the influence of the difference

 R-oF g, -

fO

t5

the channel P- p- - P pushes in the flow rate of the liquid, the greater, in order to ensure that it is rotatable and sufficiently hanging from P (and the controlled con cent of the closure element Q const the closure element of the valve

cue output is connected to the control input, 20 to indirectly judge the r.

3 flow rate, providing at the output a given constant flow Q const, coming through channel 4 and nozzles 5 to a controlled point corresponding to the installation location of nozzle 5. Linear movement of the locking element of the regulator 3 is detected by the sensor 6 linear displacement, the output of which is connected to the first input an ultrasonic unit 7, the second, third and fourth inputs of which are connected respectively to the pressure setting device 8, the flow setting device 9 and the setting device 10 of the geodesic height or differential, and the output with the indicator 11,

I

Computing unit 7 contains an approximator 12, an adder 13, multipliers 14 and 15, a subtractor 16, and setters 17 and 18, the output of the approximator being connected to the first input of the adder 13, the second input of which is connected to the output of the setpoint 17 of line 4 resistance and the output to the first input of the first multiplier 14, the second and third and the inputs of which are connected to the output of the flow setting device 9, the fourth to the output of the setting device 18, and the output to the first input of the subtractor 16, the second input of which is connected to the output of the pressure setting control 8, the third - with the release of the second multiplier 1 5, and the output is connected to the input: ator 11, the first and second inputs of the second multiplier of bodies 15 are connected respectively to the control points 18 and 10,

The device works as follows.

At the entrance to channel 4 stabilize

pressure P const, and the output (nozzles) is placed in a controlled point, characterized by pressure P (the upper index indicates the physical quantity, and the value of P characterizes the electric equivalent of p), Under the pressure difference in

 R-oF g, - f-n-P, mouth

Channel P- P- - P (P P, the auxiliary fluid flow is increased the more, the more P, In order for this flow rate to be constant and sufficiently small and not dependent on P (and also not affected by the controlled process) it is stabilized by Q const with the help of the regulator locking element. Then, by the magnitude of the hydraulic resistance of the locking element

indirectly judge the p.

Thus, by the magnitude of the displacement of the locking element stabilizing the flow rate Q, it is possible to determine its hydraulic resistance by approximating the dependence

and f (h),

(one)

thirty

35

40

where hell is the hydraulic resistance of the locking element; h is the displacement amount of the locking element.

The approximating dependence a f (h) for the closure element used can be determined either experimentally or by calculation using reference books.

Next, the total flow resistance of the channel is determined.

 a, + a

(2)

45

ajf uh

where a is the hydraulic resistance of the line and nozzle (determined in the same way as a). By this value, the pressure loss in the channel is indirectly determined

(3)

50 where p is the density of the working fluid; g - free fall acceleration,

And the pressure value at the controlled point is determined from the expression

RO - Ral iP8

(four)

- the level of transcendence (humiliation) of points with the level of PO and nozzle P,

Stabilizer 2 pressure automatically lorns the output value

wed

P const. The flow controller 3 automatically generates the output value Q - const. The change in the position of the locking element (not shown in Fig. 1) of the regulator 3, which stabilizes the Q value, allows indirect control of the P value, the Regulator 3, the hydraulic line 4 and the nozzles 5 depending on the dependence (1-4) . The hydraulic resistances of elements 4 and 5 are constant. The hydraulic resistance of the regulator 3 is indirectly determined by the displacement of its locking element, on which the sensor 6 is installed. Sensor 6 forms the value of this displacement for unit 7, performing calculations on dependencies (1-4). For the same calculations, in block 7 tf values of P, Q and h, respectively, from sensors 8–10, Sensors 8 and 9 can be replaced by setting devices. In the latter case, their installation sites are indicated by a dotted line. Sensors are preferable in the case when controlled processes require restructuring of P and Qj.

Computing unit 7 works as follows; Approximator 12 forms the value a | over the axis (I), using the measured value of h. In adder 13, the value of a is determined from dependence (2). Multiplier 14 forms the value of LP, according to dependence (3). The multiplier 15 determines the value of f.g h, and the subtractor 16 defines the value of P according to (4), which is indicated by indicator 11,

Formula inventions

A device for controlling pressure, comprising a channel; a connection; a source of pressure; an auxiliary medium.

with the medium to be measured, the flow controller installed in the channel, the displacement sensor of its gate element and the indicator, characterized in that, in order to increase the accuracy

and reliability, it is equipped with a pressure stabilizer, flow controllers, pressure and geodesic height and a computing unit with four inputs, the pressure stabilizer is installed in the channel between the auxiliary medium pressure source and the flow sensor, the output of the displacement sensor is connected to the first input of the computing unit, the second the third and fourth inputs of which are connected to the control units for the flow rate, pressure, and geodesic height, respectively, and the output is connected to the indicator.

Editor T. Parfenova

Compiled by A. Sokolovsky Tehred V. Kadar

Order 1621/39

Circulation 777 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

FIG. 2

Proofreader L. Pilipenko

Claims (1)

10 claims A pressure monitoring device comprising a channel connecting the pressure source of the auxiliary medium 15 with the medium to be measured, a flow regulator installed in the channel, a displacement sensor for its shut-off element and an indicator, characterized in that, in order to increase accuracy 20 and reliability, the oio is equipped with a pressure stabilizer , flow rate, pressure and geodetic altitude adjusters and a computing unit with four inputs, moreover, a pressure stabilizer is installed in the channel between the pressure source of the auxiliary medium and the sensor ode displacement sensor output soedinen.s ι first input of the computing unit, the second and fourth tre30 Tille whose inputs are connected with setpoint flow rate, pressure and geodetic height, respectively, and output - with an indicator.