SU1756666A1 - Hydrauilic pulser - Google Patents

Abstract

Use: generation of pressure pulsations in a liquid when testing components and assemblies operating under dynamic loads. SUMMARY OF THE INVENTION: The device comprises a valve 1 connected to a bellows 2 and an adjustable spring 3. In the working cavity 6 there is a nozzle 5 with an inlet pipe 10 and a movable pipe 8. The outlet section of the pipe 8 is derived from the housing ghadelés. 2 Il.

Description

The invention relates to devices for creating oscillations (pulsations) in a liquid and can be used, in particular, for testing components and assemblies operating under dynamic load conditions.

 A number of devices for creating pressure pulsations or flow in a liquid are known (as No. 673765, 1315668, 1366734, 1097355, 1200928).

All these devices are based on the rotational or translational movement of the regulator, which in its movement changes the flow cross section of the main line and, consequently, the pressure pulsations and flow in it.

All these devices have complex technical performance and their work is accompanied by significant alternating (dynamic) loads acting on moving parts, which reduces the reliability of their work and reduces the service life of the devices.

In addition, for their operation, an external source of energy and a propulsion unit (as a rule, an electric motor) is required, which provides the required frequency of movement of the regulator and its smooth change.

The closest in technical essence (prototype) to the claimed solution is a hydropulsator along a.s. N ° 1420254.

Fluid pressure pulsations are generated by this device by changing the volume of a hermetic collector cavity filled with a fluid with a specific gravity less than the specific gravity of the working fluid. The change in volume is made by moving the piston associated with the electric actuator; The oscillation frequency of the piston is changed by changing the frequency of rotation of the motor shaft.

This device has a number of significant drawbacks: These include the complexity of the structures, the presence of additional liquid with a specific weight lower than the specific weight of the working fluid (which is not always possible to provide), the presence of additional devices for controlling the frequency of rotation of the electric motor (for example, a rheostat).

The aim of the invention is to simplify the design and increase the reliability of the device.

The goal is achieved by the fact that in the proposed device - hydraulic

with

4 SL

ABOUT

Ltd

A pulsator comprising a housing, in the cavity of which a movable spring-loaded plate is placed, dividing the cavity of the housing into a sub-piston and drive chamber, a hermetic bellows located in the cavity of the housing and fixed at one end on the movable plate and the other communicating the piston cavity with the consumer, and the drive of the movable plate placed in the drive chamber, is made in the form of a fixed nozzle interacting with a movable plate and a movable drain pipe, installed with the possibility of moving its entrance part along the height of the drive chamber.

The essence of the device proposed is illustrated in the drawings, where in FIG. 1 shows the pulsator design; in fig. 2 - the results of experimental and theoretical studies.

The pulsator consists of a damper 1 connected to the bellows 2 and the spring 3, on which the adjusting screw 4 is installed. The valve i divides the internal space of the pulsator into two volumes working cavity 6 and spring cavity 7. In the working cavity b there is a nozzle 5 and a movable pipeline 8 with a variable gap between the outlet of the pipe 8 and the valve 1. On the pipe 8, outside the pulsator body, a valve 9 is installed. The nozzle 5 is connected to the inlet pipe 10, in which it is necessary to cause pressure or flow pulsations. The output section of the pipeline 9 is brought out of the housing of the jets and can be connected, for example, with the drain pipe 11

The device operates as follows.

Until the liquid level reached the inlet of the pipeline 8, there is no oscillation. Drainage flow Seli is uniquely determined by the gap between the nozzles 5 and the valve 1, i.e. the force to apply the springs 3. As soon as the inlet of the pipeline 8 is closed by the water level, the pressure Pc in the cavity G with the nozzle 5 will begin to increase, increase above the spring 3 setting. This will increase the gap between the flap 1 and the nozzle 5 and, consequently, further increase the input flow rate GBX, further decrease the volume of the gas cavity 6, further increase the pressure of Rcol, further increase the gap between the valve 1 and the nozzle 5, an even greater increase in the flow rate of the GBX

 Rcol leads to increased consumption for bleaching. If the damper did not have a mass, and the GBX flow rates and the belids did not have inertial characteristics. then the process of moving the shutter 1 and increasing the pressure of the Pcol would stop when bleaching GBX. (1)

However, due to the presence of these characteristics, the valve 1 will move in the direction of opening further than the equilibrium position, which will lead to an increase in the flow rate for the drain:

Seliv GBX. (2)

This will lead to a decrease in the Rcol pressure and move the damper 1 to the side of closure, reduce the flow rate GBx- of the increased volume of the gas cavity 6, decrease the pressure of the колcol, decrease the gap between the damper 1 and the nozzle 5, and further reduce the flow rate GBX. At the same time, a decrease in the Rcol pressure will lead to a decrease in the flow rate for the discharge of the Seliv. The valve 1 by inertia will be in the equilibrium position, which will lead to inequality

Seliv GBX, (3)

and the process of oscillation will move to a new cycle.

The operation of the pulsator can be described by a system of equations;

five

-d, - (Р ™., - (.., +.,) с-г

tit

 (

L - ffl Gen - PC)

-P.O.XI. ) /. "

dNon G «- Oc L fjj d« dr СC dr

m d U () P6 + fc (“с) (Con -----Х1л« ,,) dr

(four)

where GBX and Seliv are expenses, see FIG. 1; RKOL - pressure in the working cavity, see Fig.1; aql - 40 hydroresistance of the gap between the nozzle 5 and the valve 1;

635525.4 s2 / kgf cm2 at x 0.001 cm

Eccle -

3984.7 2 -

4 (o.1444- (o, 38--)

-(five)

0

five

at 0.001 x 0.03 cm 123289.3 s2 / kgf-cm2 at x 0.03 cm IBX - inertia of the inlet pipeline;

Г „х 2,434 с2 / см2;

1sl - inertia of the drain pipe;

cl 0.002 s2 / cm2.

In general, I,

where I is the length;

F is the area of the pipeline;

SWH - hydro resistance of the inlet pipeline (avh 354301.84 s2 / kgf-cm2);

Qcn is the hydraulic resistance of the discharge pipe (asl 0.1 s2 / kgf cm2);

Rnp n - the initial force applied to the valve (Rnp.H 127,1289 kgf);

Sl - stiffness total spring and 5 bellows (membrane) Sl - 3 °;

C is the coefficient of the capacity of the gas cavity of the valve (due to the isothermal conditions of the processes in the cavity), C 0.01449 cm2;

m is the mass of the moving parts of the bellows 10 and the spring.

The given numerical values of the coefficients of the system of equations (4) correspond to the design parameters of the pulsator and the conditions of spills having 15th place in the ITM of the Ukrainian Academy of Sciences.

FIG. 2 shows the results of computational and experimental studies of the operation of the pulsator, i.e. changes in the oscillation frequency of the volume of the gas cavity 6. 20

If the volume of cavity 6 is less than 200 cm. This is the mode of developed pulsations. If the volume of the cavity is greater than 600 cm3, then there are no fluctuations.

The mathematical model of the proposed 25 device is an oscillatory link not second-order, where yy, fax, tc are the coefficients characterizing the ability of the device to accumulate more linearly, you can choose their ratio so that the system goes out of a steady state and begins to generate oscillations.

Compared with the prototype, the use of the proposed device simplifies the design, improves the reliability of the pulsator and ensures a continuous change in the frequency of the pulsations without interfering with its design, which ultimately simplifies testing, improves the accuracy of the results and reduces the processing time of the tested components and components.

Claims (1)

Claims of the invention A hydraulic pulsator comprising a case in which cavity a movable spring-loaded plate is placed, dividing the cavity of the case into piston and driving chambers, a sealed bellows located in the cavity of the case and fixed with one end on the moving plate and the other communicating the piston cavity with the consumer and the drive of the movable plate placed in the drive chamber, characterized in that, in order to simplify the design and increase the natic energy, Skl and C - coefficients. 30 reliability, the drive is made in the form of non-characterizable. The ability of the device to accumulate potential energy. As is known, from the theory of automatic regulation in a system that has a kinetic and potential component, 35 a sliding nozzle interacting with the plate and a movable drain Tpy6jn-conduit installed with the possibility of moving its input part along the height of the drive chamber. one can always choose their ratio so that the system goes out of a steady state and starts generating oscillations. Compared with the prototype, the use of the proposed device simplifies the design, improves the reliability of the pulsator and ensures a continuous change in the frequency of the pulsations without interfering with its design, which ultimately simplifies testing, improves the accuracy of the results and reduces the processing time of the tested components and components. Claims of the invention A hydraulic pulsator comprising a case in which cavity a movable spring-loaded plate is placed, dividing the cavity of the case into piston and driving chambers, a sealed bellows located in the cavity of the case and fixed with one end on the moving plate and the other communicating the piston cavity with the consumer and the drive of the movable plate placed in the drive chamber, characterized in that, in order to simplify the design and increase by a sliding nozzle interacting with the plate and a movable drain Tpy6jn-conduit installed with the possibility of moving its input part along the height of the drive chamber.  - I I // --- I -t W 0t / & t