SU1681047A1 - Positive displacement hydraulic pumps checking stand - Google Patents

Abstract

The invention relates to a device for the in-diagnostics of pumps. The aim of the invention is to measure the uneven supply of volumetric hydraulic pumps when changing the parameters of the hydraulic system and simulating external influences. The bench contains tank 1, suction lines 11, injection 7 and discharge 2, block 3 of process parameter controllers, driver 4, drive motor 5 of a diagnosed hydraulic pump 6 sensors 8–10 process parameters, recorder 17 and block 18 indicating devices, as well as hydraulic pulsator 19 with drive motor

Description

The invention relates to hydraulic engineering and testing equipment, in particular, to devices for in-diagnostics of pumps.

The aim of the invention is to measure the uneven supply of volumetric hydraulic pumps when changing the parameters of the hydraulic system and simulating external influences,

FIG. 1 shows a stand for diagnostics of volumetric hydraulic pumps, general view; in fig. 2-4 - typical irregularities in the supply of volumetric hydraulic pumps.

The stand for diagnostics of volumetric hydraulic pumps (Fig. 1) contains a reservoir 1 with a working fluid, installed at the outlet of the discharge line 2, a block 3 of process parameter controllers connected, on the one hand, to the driver 4, and on the other hand, to the driven engine 5 the hydraulic pump 6 with the injection line 7, the functional systems of the tank 1 (heating elements, a heat exchanger, a system for ensuring a predetermined pressure at the inlet to the hydraulic pump 6, and others not shown in Fig. V, as well as with return circuits According to sensors 8-10 process parameters, respectively, volume flow, pressure, temperature, installed on suction line 11, and speed sensor 12 of the drive motor 5. Volume flow sensors 8, pressure 9, temperature 10 and frequency 12 of the rotation of the drive engine 5 are simultaneously connected electrically, respectively, with the recorder 17 and the indicating device block 18. The stand is equipped with a hydropulsator 19, its drive motor 20, controlled by the block 3 of process parameter controllers, as well as sensors 21, 22 s The output parameters of the hydropulsator 19 are the amplitudes of the movement of the hydropulsator plunger 19 and the rotational speed of the hydropulsator drive motor connected by electrical connections 23 and 24, respectively, with the recorder, the indicating instrument unit and the process parameter regulator unit. The output 25 of the hydropulsator 19 is connected by a crosspiece 26 to a load line 27, the output of which is a system 28 of hydraulic elements (pulsation dampers, filters, valves, throttles, etc.), an output (discharge line) 7 of the hydraulic pump 6 and a pressure sensor 29 connected by an electrical connection 30 with the recorder 17, a block 18 of pointing devices and a block of 3 process parameter controllers.

The device works as follows.

The diagnostics program (tests) laid by the operator in the memory of the driver 4 is fed to the block 3 of the process parameter controllers (Fig. 1).

Regulatory influences in the form of electrical signals from the block 3 of the process parameter controllers are fed to the drive motor 5 of the hydraulic pump b, to the drive motor 20 of the pulsator 19 and to

functional systems of the reservoir. 1. Signals of process parameters for feedback circuits 5-12-16, 26-29-30, 19-21- 23. 20-22-24, 1-11-9-14 and 1- 11-10-15 arrive simultaneously at block 3

regulators, on the recorder 17 and the block 18 pointing devices. Unit 3 of process parameter controllers, sending electrical signals of regulatory actions to the drive motor 5 of the diagnosed

the hydraulic pump 6, the drive motor 20 of the hydropulsator 19 and the functional systems of the tank 1, provide the operating modes of the hydraulic pump 6, the supply of hydraulic calibration signals to the system and

given conditions of its functioning. The measurement of supply irregularity is achieved by indirect measurements using the functional dependence of the injection pressure on the hydraulic pump supply. Typical

graphs of pressure fluctuations excited by the hydropulsator and the hydraulic pump during their separate and joint work are shown respectively in FIG. 2-4.

Since the superposition (overlay) method is applicable for linear systems, the variable component of the injection pressure at the cross is considered as the sum of the variable pressures due to the flow of the hydraulic machine and the hydraulic pulsator.

The total variable pressure by sensor 29 (Fig. 1) is converted into a total electrical signal (Fig. 4) fed to recorder 17.

The first component of this sum is that the flow unevenness is proportional to the measured variable pressure that occurs when only one hydraulic machine is operating. The converted electrical signal from the sensor 29, fed to the recorder 17, is shown in FIG. 3. To decipher the signal of this component, a unit of measure (scale) is necessary.

The second component is the uneven supply (conditionally) of only one pulsator. The pressure caused (conditionally) by the operation of only one pulsator is converted by the sensor 29 into an electrical signal (Fig. 2), which is fed to the recorder 17. The convention is that the pulsator is not included in isolation from the hydraulic machine. The readings of the isolated pulsator are metrologically unreliable because of the possibility of deviations in the physical properties of the non-flowing fluid. Therefore, the graph shown in FIG. 2 is actually viewed as the envelope of the vertices of the graph shown in FMG. 4, The purpose of the signal to the second component is to participate in determining the missing scale.

By accurately measuring the area of the pulsator plunger and carefully recording its stroke, the amount of compression of a portion of the working fluid by its plunger is calculated. The sought scale is defined as the volume of this compressed portion, referred to the corresponding increment of the electrical envelope signal over the half cycle of the pulsator. In other words, the scale is the maximum flow of the pulsator, referred to the difference of the amplitudes of the envelope of the total electrical signal of the hydraulic machine and the pulsator for half the compression period.

The scale thus obtained allows one to transform the recording of the electrical signal of the diagnosed hydraulic machine (Fig. 3) into the form of a variable compression volume over time, i.e. in bulk form

R.NPa

$ 2

feed irregularities for programmed conditions.

The magnitude of the hydraulic calibration signals of the hydropulsator and the irregularities in the supply of the hydraulic machine should be comparable, since a significant decrease in the calibration signals reduces the accuracy of measurements, and their disproportionate increase may cause functional impairment.

Due to the presence of a hydropulsator controlled by frequency v, the amplitude of the set hydraulic signals that it reproduces, the stand allows accurate measurements of the irregularity of the flow of hydraulic pumps when they work in a hydraulic system with any given parameters.

Claims (1)

Invention Formula A stand for diagnostics of volumetric hydraulic pumps, containing a reservoir with a working fluid, suction lines, pumps and discharges, a block of process parameter controllers connected on the one hand to the driver, and on the other hand to the drive engine of the diagnosed hydraulic pump, functional systems of the reservoir, chain feedback of sensor parameters of the process and recorder, characterized in that, in order to measure the irregularity of supply of volumetric hydraulic pumps when changing the parameters of the hydraulic system and mitigation of external influences, the stand is equipped with a hydro pulsator, its drive motor, controlled by a block of process parameter controllers and sensors of the output parameters of a hydro pulsator connected simultaneously with a block of process parameter controllers, a recorder and a block of pointing devices, the output of a hydro pulsator is connected to , the output of the diagnosed hydraulic pump and the discharge pressure sensor associated with the block of process parameter controllers, the recorder and the block indicating the moat. 21 / 3 0.00 0.0 7 0.11 FIG. Z 0.16 0.20 t, c 0,000,0ft0,080,120,160,20 Fig.z 17 / J 0,000,0 0.080.11 Fy 0.20 t, c