CN204439307U - For the pressure detection oil circuit of minute leakage pick-up unit - Google Patents
For the pressure detection oil circuit of minute leakage pick-up unit Download PDFInfo
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- CN204439307U CN204439307U CN201520167592.6U CN201520167592U CN204439307U CN 204439307 U CN204439307 U CN 204439307U CN 201520167592 U CN201520167592 U CN 201520167592U CN 204439307 U CN204439307 U CN 204439307U
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- pressure
- oil circuit
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Abstract
The utility model proposes a kind of structure simple, the pressure detection oil circuit for minute leakage pick-up unit that accuracy of detection is high, it comprises fluid supply source, fluid drive unit, three position four-way directional control valve, hydraulic control one-way valve, fluid reservoir, pressure transducer, thermometer, surplus valve, the liquid that fluid supply source stores is after being driven by fluid drive unit, connected with the first flow path and the second stream being connected to the two ends that system under test (SUT) is connected by three position four-way directional control valve, form loop, first flow path is provided with hydraulic control one-way valve, fluid reservoir, for detecting the pressure transducer of the pressure of fluid reservoir and the thermometer for the temperature that detects fluid reservoir, in the downstream of fluid drive unit, surplus valve is installed.
Description
Technical field
The present invention relates to a kind of pressure detection oil circuit for minute leakage pick-up unit.
Background technology
At present, under the usual 20MPa of high pressure conditions, during measuring flow, available flowmeter is a lot, such as orifice flowmeter, nozzle flowmeter, differential pressure flowmeter, snail street flowmeter, turbo flow meter, target type meter etc., can also use gear meter, oval gear flowmeter, Roots type flowmeter and rotary piston flowmeter etc.) volumeter.
Wherein, the range ratio of orifice flowmeter is 3:1, and low discharge precision is low.Nozzle flowmeter, range ratio is 3:1, and same low discharge precision is low.And differential pressure flowmeter, snail street flowmeter, turbo flow meter, target type meter etc., withstand voltage lower than 6.4MPa, low discharge precision is low.Owing to there is moving component, thus inevitably there is leakage in volumeter, tiny flow quantity accuracy of detection is low.Therefore, the minimum flow that these flowmeters can be measured generally is not less than 500ml/min, thus needs a kind of pressure detection oil circuit that can detect minute leakage.
Summary of the invention
The object of the invention is for the technological deficiency existed in prior art and propose the pressure detection oil circuit for minute leakage pick-up unit that a kind of structure is simple, accuracy of detection is high.
Following technical scheme is adopted for realizing object of the present invention.
The pressure detection oil circuit for minute leakage pick-up unit of technical scheme 1, comprise fluid supply source, fluid drive unit, three position four-way directional control valve, hydraulic control one-way valve, fluid reservoir, pressure transducer, thermometer, surplus valve, the liquid that described fluid supply source stores is after being driven by described fluid drive unit, connected with the first flow path and the second stream being connected to the two ends that system under test (SUT) is connected by described three position four-way directional control valve, form loop, described first flow path is provided with described hydraulic control one-way valve, described fluid reservoir, for detecting the described pressure transducer of the pressure of described fluid reservoir and the described thermometer for the temperature that detects described fluid reservoir, in the downstream of described fluid drive unit, described surplus valve is installed.
The pressure detection oil circuit for minute leakage pick-up unit of technical scheme 2, in technical scheme 1 in the pressure detection oil circuit of minute leakage pick-up unit, described first flow path is also provided with flowmeter.
The pressure detection oil circuit for minute leakage pick-up unit of technical scheme 3, in technical scheme 2 in the pressure detection oil circuit of minute leakage pick-up unit, described first flow path is also provided with the tensimeter of the pressure for detecting described fluid reservoir.
Compared with prior art, the present invention has following beneficial effect.
According to the pressure detection oil circuit for minute leakage pick-up unit of technical scheme 1, first three-position four-way valve is made to be positioned at left position, pressurising is carried out to system under test (SUT), the pressure of the liquid in fluid reservoir is measured by pressure transducer, then three-position four-way valve is made to be positioned at meta, cut off the pressurising to system under test (SUT), maintain pressure one end time of system under test (SUT), and the pressure of the liquid in fluid reservoir is measured by pressure transducer, now, three-position four-way valve is arranged in the force value that the force value of the system under test (SUT) of the Plenum Process of left position and three-position four-way valve be positioned at the maintenance system under test (SUT) of meta and is transported to Electronic saving control device, if system under test (SUT) leaks, then in the process of pressure maintaining system under test (SUT), the pressure of fluid reservoir can reduce, now can according to pressure differential, and calculate leakage rate by above-mentioned formula.In addition, after detection leakage rate, make three-position four-way valve be positioned at right position, now to hydraulic control one-way valve input pressure, hydraulic control one-way valve is opened, and forms reverse stream, thus can make system under test (SUT) return.By such pick-up unit, can with simple structure, low cost, measures the leakage of tiny flow quantity accurately.
According to the pressure detection oil circuit for minute leakage pick-up unit of technical scheme 2, flowmeter can being set in described first flow path, like this when leakage rate is large, not by calculating, just can detecting leakage flow by means of only flowmeter.Therefore, structure is simple, easy to use.
According to the pressure detection oil circuit for minute leakage pick-up unit of technical scheme 3, tensimeter can be set in first flow path, and the switch to be connected with tensimeter, like this when pressure transducer lost efficacy, by the pressure of tensimeter artificial cognition fluid reservoir, then manually can calculate according to formula.Thus can the situation of answering pressure sensor degradation.
Accompanying drawing explanation
Fig. 1 is the system chart representing minute leakage pick-up unit of the present invention.
Fig. 2 is the schematic diagram representing the pressure detection oil circuit for minute leakage pick-up unit of the present invention.
Fig. 3 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in Plenum Process of the present invention.
Fig. 4 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in leakage measuring instrumentation process of the present invention.
Fig. 5 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in return process of the present invention.
Fig. 6 is the schematic diagram representing Electronic saving control device of the present invention.
Fig. 7 represents that minute leakage pick-up unit of the present invention carries out the process flow diagram measured.
Embodiment
With reference to the accompanying drawings embodiments of the present invention are described in detail.
Fig. 1 is the system chart representing minute leakage pick-up unit of the present invention.Fig. 2 is the schematic diagram representing the pressure detection oil circuit for minute leakage pick-up unit of the present invention.Fig. 3 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in Plenum Process of the present invention.Fig. 4 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in leakage measuring instrumentation process of the present invention.Fig. 5 is the schematic diagram of the liquid flow direction represented in the pressure detection oil circuit in return process of the present invention.Fig. 6 is the schematic diagram representing Electronic saving control device of the present invention.Fig. 7 represents that minute leakage pick-up unit of the present invention carries out the process flow diagram measured.
As shown in Figures 1 to 7, the pressure detection oil circuit for minute leakage pick-up unit of the present invention, has pressure detection oil circuit 1, Electronic saving control device 2 and display device 3.
This pressure detection oil circuit 1 comprises fluid supply source 10, fluid drive unit 20, three position four-way directional control valve 30, hydraulic control one-way valve 40, fluid reservoir 50, pressure transducer 60, thermometer 70, surplus valve 80.The liquid that fluid supply source 10 stores, after being driven by fluid drive unit 20, connects L2 by three position four-way directional control valve 30 with the first flow path L1 and the second stream being connected to the two ends that system under test (SUT) is connected, forms loop.First flow path L1 being provided with hydraulic control one-way valve 40, fluid reservoir 50, for detecting the pressure transducer 60 of the pressure of fluid reservoir 50 and the thermometer 70 for the temperature that detects fluid reservoir 50, in the downstream of fluid drive unit 20, surplus valve 80 being installed.
This Electronic saving control device 2 is connected with pressure detection oil circuit 1, controls the switching of three position four-way directional control valve 30, reads the pressure of pressure transducer 60, and according to formula:
calculate leakage rate.
This display device 3 is connected with Electronic saving control device 2, for showing the leakage rate that Electronic saving control device 2 calculates.
Below, principle of the present invention and embodiment is illustrated.
The present invention draws according to the expansiveness principle of fluid.Fluid makes to have compressible, is p for pressure
0, volume is V
0liquid, when pressure increase Δ p, volume reduces Δ V, then the compressibility volume available compressibility coefficient κ of this liquid, and the volume relative variation namely under unit pressure change represents.
Formula 1:
Because the volume of liquid during pressure increase reduces, therefore the right of above formula 1 must add a negative sign, with make κ be on the occasion of.The inverse of liquid volume compressibility coefficient, is called the bulk modulus K of liquid, i.e. K=1/ κ.
K represents the pressure increment produced required for unit volume relative variation.In actual applications, conventional K value illustrates the size of liquid opposing compressed capability.At normal temperatures, bulk modulus K=(1.4 ~ the 2) × 103MPa of pure fluid, and the elastic modulus of steel is 2.06 105MPa, the compressibility of fluid is 100 ~ 150 times of steel.Even like this, the bulk modulus numerical value of fluid is still very large, generally can think that fluid is incompressible.Such as, but in some cases, the dynamic perfromance in research hydrostatic transmission, comprises the impulsive force calculating liquid stream, vibrostability, the transient process of work and when calculating remote-controlled hydraulic mechanism, often must consider the compressibility of hydraulic oil.
K value and temperature, pressure are relevant.When temperature raises, K value reduces, and in the scope that hydraulic oil normally works, K value has the change of 5 ~ 25%; During pressure increase, K value increases, but is thisly changed to nonlinear, and as p >=3.0MPa, K value substantially no longer increases.The large I of K value is tested according to the method for national Specification.
The expansiveness principle of fluid can be known by inference according to the compressibility of aforementioned fluid.Suppose to be closed in cavity volume, pressure is p
0, volume is V
0, the moment is t
0liquid, elapsed time Δ t (Δ t=t
0– t
1) after, pressure is reduced to p
1, volumetric expansion is V
1, the moment is t
1liquid, pressure reduces Δ p=p
0– p
1, volume change Δ V=V
0– V
1, now,
Formula 2:
In formula, q is leakage flow, i.e. the volume of unit interval expansion.When namely there is minute leakage when between system under test (SUT) hydraulic cylinder piston and cylinder body, measure leakage flow by above-mentioned principle.
The present invention produces based on above-mentioned principle, comprising pressure detection oil circuit, for measuring before and after leakage when system under test (SUT) leaks, then in Electronic saving control device, carry out calculating to obtain leakage flow according to formula 2, such can obtain the high pick-up unit of measuring accuracy.
This pressure detection oil circuit being used for minute leakage pick-up unit detects as follows.First pressurising is carried out to detected system, as shown in Figure 3, in Plenum Process, Electronic saving control module makes three-position four-way valve be positioned at left side, and oil-feed oil circuit is formed as: the left position → turbo flow meter → hydraulic control one-way valve → fluid reservoir → left chamber of system under test (SUT) hydraulic cylinder of fuel tank → system under test (SUT) gear-type pump → two-position four-way solenoid directional control valve.Oil return circuit is formed as: the left position → fuel tank of system under test (SUT) hydraulic cylinder right chamber → two-position four-way solenoid directional control valve.Pressure transducer can measure the pressure in cavity volume fluid reservoir, and thermometer can measure the temperature in fluid reservoir, the pressure of fluid reservoir when system under test (SUT) surplus valve setting system under test (SUT) hydraulic cylinder stops.
Then, cut off the pressurising to system under test (SUT), the system under test (SUT) a period of time be held pressurised, detect the pressure of the fluid reservoir after there is minute leakage.That is, as shown in Figure 4, Electronic saving control device makes three-position four-way valve be positioned at meta, now gear-type pump off-load, and oil circuit is formed as: fuel tank → system under test (SUT) gear-type pump → two-position four-way solenoid directional control valve meta → fuel tank.Under this state, it is zero that hydraulic control one-way valve controls mouth pressure, positiver sealing can be ensured, the leakage of a tiny bit can not be produced, if during system under test (SUT) generation minute leakage, according to the expansiveness principle of aforementioned fluid, the pressure in fluid reservoir can reduce, and measures and calculate leakage flow by above-mentioned principle.
It is below example.
If bulk modulus K=1.6 × 103MPa, pressure p
0=6.9MPa, p
1=4.0MPa, pressure reduces Δ p=p
0– p
1=2.9MPa, V
0=2.5L, t
0=5.0s, t
1=15.0s, Δ t=t
1– t
0=10.0s, then
Finally, make system under test (SUT) liquid return, as shown in Figure 5, Electronic saving control device makes three-position four-way valve be positioned at right position, and oil-feed oil circuit is formed as: the fuel tank → right position of system under test (SUT) gear-type pump → two-position four-way solenoid directional control valve → right chamber of system under test (SUT) hydraulic cylinder (simultaneously opening hydraulic control one-way valve).Oil return circuit is formed as: the left chamber → fluid reservoir → right position → fuel tank of hydraulic control one-way valve → turbo flow meter → two-position four-way solenoid directional control valve of system under test (SUT) hydraulic cylinder.Make system under test (SUT) return thus.
According to the pressure detection oil circuit for minute leakage pick-up unit of the present invention, it has pressure detection oil circuit, Electronic saving control device, the three-position four-way valve of oil circuit can be detected by controlled pressure by Electronic saving control device, first three-position four-way valve is made to be positioned at left position, pressurising is carried out to system under test (SUT), the pressure of the liquid in fluid reservoir is measured by pressure transducer, then three-position four-way valve is made to be positioned at meta, cut off the pressurising to system under test (SUT), maintain pressure one end time of system under test (SUT), and the pressure of the liquid in fluid reservoir is measured by pressure transducer, now, three-position four-way valve is arranged in the force value that the force value of the system under test (SUT) of the Plenum Process of left position and three-position four-way valve be positioned at the maintenance system under test (SUT) of meta and is transported to Electronic saving control device, if system under test (SUT) leaks, then in the process of pressure maintaining system under test (SUT), the pressure of fluid reservoir can reduce, now can according to pressure differential, and calculate leakage rate by above-mentioned formula.In addition, after detection leakage rate, make three-position four-way valve be positioned at right position, now to hydraulic control one-way valve input pressure, hydraulic control one-way valve is opened, and forms reverse stream, thus can make system under test (SUT) return.By such pick-up unit, can with simple structure, low cost, measures the leakage of tiny flow quantity accurately.
In the present invention, fluid drive unit 20 can use gear-type pump, is certainly not limited thereto, and can use other driving pumps, such as coupling fluid-structure formula pump, belt driven type pump.
In addition, flowmeter 100 can be also provided with on first flow path L1.Can use that turbine flow connects, electromagnetic flowmeter, ultrasonic flow meter etc.Like this when leakage rate is large, not by calculating, just leakage flow can be detected by means of only flowmeter.Therefore, structure is simple, easy to use.
In addition, the tensimeter 110 of the pressure for detecting fluid reservoir 50 also can be installed on first flow path L1.Like this when pressure transducer lost efficacy, by the pressure of tensimeter artificial cognition fluid reservoir, then manually can calculate according to formula.Thus can the situation of answering pressure sensor degradation.
In addition, Electronic saving control device 2 can comprise single-chip microcomputer, power module, serial communication modular, voltage output module, signal input circuit, display circuit.Power module, serial communication modular, voltage output module, signal input circuit, display circuit are connected with single-chip microcomputer.By such Electronic saving control device can automatically detection computations generation minute leakage time leakage flow, thus control convenient, be easy to operation.
In addition, Electronic saving control device 2 can also comprise reset circuit.Initialization can be carried out before each detection like this, be more conducive to identified leakage flow like this.
In addition, Electronic saving control device 2 can also comprise warning circuit.Like this when detecting leakage, can report to the police, being convenient to management.
Such as, as shown in Figure 6, the DC power supply of Electronic saving control module Circnit Layout 12 or 24V.Electronic saving control module, comprises, reset circuit, signal input circuit, single-chip microcomputer, warning circuit, display circuit, power module, serial communication modular and high power adjustable pressure output module.Reset circuit is electrically connected with single-chip microcomputer, after the original signal of signal input circuit receiving sensor, and input single-chip microcomputer.The output of single-chip microcomputer, presses output module to be electrically connected with warning circuit, display circuit, power module, serial communication modular and high power adjustable respectively.The DC Vehicular accumulator cell voltage transitions of 12V or 24V is the integrated circuit voltage of 3.3V and 5V by power module.Reset circuit provides reset function for single-chip microcomputer.Warning circuit provides beep and LED flash to show warning.Serial communication modular can realize the serial communication of single-chip microcomputer and computing machine.High power adjustable pressure output module provides the linear adjustable voltage of 9 ~ 17V for solenoid valve.Display circuit is responsible for data measured, chart to show.Electronic saving control module is electrically connected to each other by RS232 or the RS422/485 series interfaces of industrial standard and display unit, monitored by the ferromagnetic particle quality in display unit lubricating system oil circuit, the current condition information of display device wear data and this device and warning and warning message, operating personnel are paid close attention to just developing, or imminent machinery and equipment operational failure.
In addition, Fig. 7 illustrates the flow process of the single chip circuit master routine of Electronic saving control module, first carries out initial assignment, then start Plenum Process, when making three-position four-way valve be positioned at left position, time t starts to increase progressively with 0.1s step-length, after carrying out Plenum Process 5s, record pressure p
0.Then start leakage process, make three-position four-way valve be positioned at meta, time t starts to increase progressively with 0.1s step-length, record pressure p
1, calculate and show q, finally completing the test of high pressure minute leakage q.
In addition, each embodiment above-mentioned is only a kind of embodiment, and each embodiment above-mentioned combination in any can form various may connection, and this combination is also contained in protection scope of the present invention.
Above the pressure detection oil circuit for minute leakage pick-up unit of the preferred embodiment of the present invention is illustrated, but, the present invention is not limited to above-mentioned concrete embodiment, only otherwise depart from the scope of claim, can carry out various distortion or change.Present invention resides in the various distortion in the scope of claim and change.
Claims (3)
1., for a pressure detection oil circuit for minute leakage pick-up unit, it is characterized in that,
Comprise fluid supply source, fluid drive unit, three position four-way directional control valve, hydraulic control one-way valve, fluid reservoir, pressure transducer, thermometer, surplus valve,
The liquid that described fluid supply source stores, after being driven by described fluid drive unit, is connected with the first flow path and the second stream being connected to the two ends that system under test (SUT) is connected by described three position four-way directional control valve, forms loop,
Described first flow path being provided with described hydraulic control one-way valve, described fluid reservoir, for detecting the described pressure transducer of the pressure of described fluid reservoir and the described thermometer for the temperature that detects described fluid reservoir, in the downstream of described fluid drive unit, described surplus valve being installed.
2. the pressure detection oil circuit for minute leakage pick-up unit according to claim 1, is characterized in that, described first flow path is also provided with flowmeter.
3. the pressure detection oil circuit for minute leakage pick-up unit according to claim 2, is characterized in that, described first flow path is also provided with the tensimeter of the pressure for detecting described fluid reservoir.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520167592.6U CN204439307U (en) | 2015-03-24 | 2015-03-24 | For the pressure detection oil circuit of minute leakage pick-up unit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520167592.6U CN204439307U (en) | 2015-03-24 | 2015-03-24 | For the pressure detection oil circuit of minute leakage pick-up unit |
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| Publication Number | Publication Date |
|---|---|
| CN204439307U true CN204439307U (en) | 2015-07-01 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112303060A (en) * | 2020-09-22 | 2021-02-02 | 河北雷萨重型工程机械有限责任公司 | Hydraulic oil detection system and hydraulic system |
-
2015
- 2015-03-24 CN CN201520167592.6U patent/CN204439307U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112303060A (en) * | 2020-09-22 | 2021-02-02 | 河北雷萨重型工程机械有限责任公司 | Hydraulic oil detection system and hydraulic system |
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150701 Termination date: 20190324 |
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| CF01 | Termination of patent right due to non-payment of annual fee |