CN103423222A - Proportional pressure combination control valve, hydraulic system and system pressure switching method - Google Patents
Proportional pressure combination control valve, hydraulic system and system pressure switching method Download PDFInfo
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- CN103423222A CN103423222A CN2012101547736A CN201210154773A CN103423222A CN 103423222 A CN103423222 A CN 103423222A CN 2012101547736 A CN2012101547736 A CN 2012101547736A CN 201210154773 A CN201210154773 A CN 201210154773A CN 103423222 A CN103423222 A CN 103423222A
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Abstract
The invention relates to a proportional pressure combination control valve, a hydraulic system and a system pressure switching method. The proportional pressure combination control valve comprises at least two pressure control valve sets and a high-and-low pressure switching valve set, wherein the pressure control valve sets and the high-and-low pressure switching valve set are connected in parallel, and the high-and-low pressure switching valve set comprises a proportional overflow valve which controls pressure to carry out linear changes through input current with linear changes. The hydraulic system comprises the proportional pressure combination control valve and a logic control element set, wherein the logic control element set comprises an electromagnetic valve control element which controls an electromagnetic coil of an electromagnetic valve to be energized or be de-energized, and a proportional overflow valve control element which controls the input current of an electromagnetic coil of the proportional overflow valve in the high-and-low pressure switching valve set to carry out the linear changes. The proportional pressure combination control valve, the hydraulic system and the system pressure switching method can effectively avoid impact of the hydraulic system, and can further achieve linear control over bidirectional switching between the high pressure and the lower pressure.
Description
Technical field
The present invention relates to engineering, relate in particular to a kind of ratio pressure combined control valve, hydraulic system and system pressure switching method.
Background technique
Crawler crane is a kind of truss-type cantilever crane structure hoist that adopts caterpillar band traveling chassis, and the load of this hoist normally frequently changes.The load difference, the mechanism of crawler crane is stressed just different.Therefore under the unequally loaded operating mode, if make each mechanism's smooth running, just need artificially to its mechanism's additional forces, so that its smooth running under the stress balance state.
The everything of crawler crane is all to drive to realize by hydraulic system, and a lot of mechanisms' (such as mast motion, vehicle frame elevator mechanism etc.) drive or support by hydraulic jack.In order to adapt to the unequally loaded operating mode, need to be controlled the hydraulic jack ouput force.And the size of hydraulic jack ouput force is determined by its hydraulic system pressure size and pressure-acting size.After the hydraulic jack moulding, the pressure-acting area can't change with regard to becoming determined value.Therefore, if want to change the size of hydraulic jack ouput force, can only realize by the size that changes hydraulic system pressure.
The ideal process that hydraulic jack ouput force size changes is: from a certain value linear transitions, to another, be worth, namely hydraulic system pressure is worth to another from a certain value linear transitions.The linear transitions here refer to hydraulic system pressure within a certain period of time from a force value continuously and transition at the uniform velocity be the pattern (referring to Fig. 2) of another force value.If hydraulic system pressure is suddenlyd change (referring to Fig. 1) between two different values, this sudden change will cause the stressed sudden change of mechanism and violent shake, when serious, can make crawler crane generation security incident.
In order to overcome the problem of pressure jump, be to use liquid resistance Throttle Principle to be cushioned aspect the switching of the hydraulic system in current crawler crane between the different pressures value.Its scheme is: when hydraulic system pressure switches from large value to little value, utilize liquid resistance release portion fluid, make its pressure drop to slowly requirements.Concrete hydraulic system structure as shown in Figure 3.
In Fig. 3, the rodless cavity of the pressure hydraulic fluid port connecting fluid cylinder pressure 2 of oil hydraulic pump 1 and the filler opening of two-stage pressure controlled valve, the rod chamber of oil hydraulic cylinder 2 directly communicates with hydraulic oil container 3, and the oil return of two-stage pressure controlled valve 4 directly communicates with hydraulic oil container 3.Two-stage pressure controlled valve 4 consists of low pressure relief valve 4.1, high-pressure overflow valve 4.2, solenoid valve 4.3,4.4 and liquid resistance 4.5, and Placement is referring to Fig. 3.
When the hydraulic system in Fig. 3 need to keep high pressure conditions, make the coil of the electromagnet Y2 of the coil of electromagnet Y1 of solenoid valve 4.3 and solenoid valve 4.4 all must not electricity, high-pressure overflow valve 4.2 keeps higher system pressure; When the needs hydraulic system keeps low-pressure state, the coil of the electromagnet Y1 of solenoid valve 4.3 is obtained electric, low pressure relief valve 4.1 keeps lower system pressure.When hydraulic system is switched from high pressure conditions to low-pressure state, at first make the coil of electromagnet Y1 of solenoid valve 4.3 and solenoid valve 4.4 electromagnet Y2 coil simultaneously electric, in process
Make the coil losing electricity of the electromagnet Y2 of solenoid valve 4.4 after time,
In time, hydraulic system can utilize the liquid resistance to carry out pressure buffer, and the buffer function hindered by liquid is eliminated the impact of pressure jump, when hydraulic system is switched from low-pressure state to high pressure conditions, does not cushion.
In this liquid resistance throttling scheme, its pressure switching still belongs to non-linear process.When pressure difference value is very large, cushioning effect is unsatisfactory.The physical dimension of liquid resistance self is minimum, is easy to be stopped up by foreign material and causes the pressure jump phenomenon.The time that the physical dimension of liquid resistance self and buffering course need
Two parameters all are difficult to accurately calculates, and are all at present to draw empirical value according to debug products repeatedly.This causes very burden for batch production.To commissioning staff's professional skill, require also very high simultaneously.
For the switching between multistage pressure, liquid resistance throttling buffering is difficult to carry out different Cushioning Design according to each stage, can only carry out the passive adaptation buffering with same damping hole, and effect is very undesirable.
Summary of the invention
The objective of the invention is to propose a kind of ratio pressure combined control valve, hydraulic system and system pressure switching method, can realize linearizing system pressure handoff procedure, reduce the technical difficulty of hydraulic system assembling and debugging.
For achieving the above object, the invention provides a kind of ratio pressure combined control valve, comprise: at least two pressure controlled valve groups and high/low pressure cut-over valve group, described at least two pressure controlled valve groups and high/low pressure cut-over valve group form relation in parallel, and described high/low pressure cut-over valve group comprises by the proportional pressure control valve of the input current pilot pressure linear change of linear change.
Further, described high/low pressure cut-over valve group also comprises first solenoid valve of connecting with described proportional pressure control valve, and described the first solenoid valve is normally closed solenoid valve.
Further, but the relief valve that each pressure controlled valve group has the set pressure value, the set pressure value also comprises second solenoid valve of connecting with described relief valve lower than the pressure controlled valve group of the highest set pressure value, described the second solenoid valve is normally closed solenoid valve.
For achieving the above object, the present invention also provides a kind of hydraulic system, have aforesaid ratio pressure combined control valve and logic control element group, described logic control element group comprises: the electromagnet coil of controlling solenoid valve obtains the electromagnetic valve element and the proportional pressure control valve control unit of controlling the input current linear change of the electromagnet coil of proportional pressure control valve in the high/low pressure cut-over valve group of electric or dead electricity.
For achieving the above object, the present invention also provides a kind of hydraulic system pressure switching method, comprising:
When the system pressure of hydraulic system is prepared to be switched to the second force value from the first force value, the proportional pressure control valve control unit in described hydraulic system is controlled at the input current of the proportional pressure control valve in the high/low pressure cut-over valve group and the corresponding current value of the force value that is not less than described the first force value;
Electromagnetic valve element in described hydraulic system makes the electromagnet coil dead electricity of set pressure value lower than the solenoid valve in the pressure controlled valve group of described the first force value or the second force value;
Described proportional pressure control valve control unit is controlled the input current linear change of described proportional pressure control valve to current value corresponding to described the second force value.
Further, if described high/low pressure cut-over valve group also comprises first solenoid valve of connecting with described proportional pressure control valve, when the system pressure of described hydraulic system is prepared to be switched to the second force value from the first force value, described proportional pressure control valve control unit is controlled at the input current of described proportional pressure control valve and the corresponding current value of the force value higher than described the first force value, and before the input current linear change of controlling described proportional pressure control valve, time delay Preset Time interval, and it is electric by described electromagnetic valve element, the electromagnet coil of described the first solenoid valve to be obtained.
Further, described Preset Time interval according to described proportional pressure control valve by dynamically to the set of time of stable state.
Further, when the system pressure of described hydraulic system is switched to described the second force value, make proportional pressure control valve and the equal dead electricity of the first solenoid valve in described high/low pressure cut-over valve group.
Based on technique scheme, the present invention has adopted the major function that proportional pressure control valve switches as high low pressure to realize unit, the characteristics of proportional routine linear relationship between the input current of proportion of utilization relief valve and pilot pressure, realize the control procedure of the linear change of system pressure by control inputs electric current linear change, process by this pressure linear change, the impact of hydraulic system can be effectively avoided, the linearity control of the two-way switching of high low pressure can also be realized simultaneously.
The accompanying drawing explanation
Accompanying drawing described herein is used to provide a further understanding of the present invention, forms the application's a part, and schematic description and description of the present invention the present invention does not form inappropriate limitation of the present invention for explaining.In the accompanying drawings:
The curve synoptic diagram that Fig. 1 is the hydraulic system pressure sudden change.
The curve synoptic diagram that Fig. 2 is the hydraulic system pressure linear change.
The liquid resistance Throttle Principle schematic diagram that Fig. 3 is hydraulic system in prior art.
The embodiment's that Fig. 4 is hydraulic system of the present invention principle schematic.
The electric current that Fig. 5 is the proportional pressure control valve in ratio pressure combined control valve embodiment of the present invention
Schematic diagram with pressure characteristic.
The embodiment's that Fig. 6 is hydraulic system pressure switching method of the present invention schematic flow sheet.
Embodiment
Below by drawings and Examples, technological scheme of the present invention is described in further detail.
At first several technical terms are explained, as follows:
Relief valve: i.e. pressure controlled valve, control the oil liquid pressure in hydraulic system, to meet the demand of final controlling element to ouput force, output torque and motion state.
Proportional pressure control valve: the oil liquid pressure in hydraulic system is carried out to proportional control, according to the difference of input current signal, draw different oil liquid pressures.
As shown in Figure 4, be an embodiment's of hydraulic system of the present invention principle schematic.In the present embodiment, hydraulic system has ratio pressure combined control valve 5 and logic control element group (not shown in FIG.), except these parts, hydraulic system also has oil hydraulic pump 1, oil hydraulic cylinder 2 and hydraulic oil container, provided a kind of composition schematic diagram of feasible each parts of hydraulic system in Fig. 4, mainly for the basic running of hydraulic system of the present invention is described, be understood that, other hydraulic systems with ratio pressure combined control valve 5 and logic control element group also allow other structural form, as long as can realize that the purpose of the linearity switching of system pressure just should be looked, be encompassed in the middle of the technological scheme scope that the present invention asks for protection.
At first, first just the structure of the ratio pressure combined control valve 5 shown in Fig. 4 describes.This ratio pressure combined control valve 5 comprises at least two pressure controlled valve groups and high/low pressure cut-over valve group, and at least two pressure controlled valve groups and high/low pressure cut-over valve group form relation in parallel.Different pressure controlled valve groups, for the system pressure of hydraulic system is controlled, can be kept two kinds of system force value by least two pressure controlled valve groups.Two groups of pressure controlled valve groups have been shown in Fig. 4, respectively the first pressure controlled valve group and the second pressure controlled valve group, the first pressure controlled valve group is comprised of the relief valve 5.1 of series connection and the solenoid valve 5.4 of Normally closed type, and the second pressure controlled valve group is comprised of the relief valve 5.2 of series connection.Except the pressure controlled valve group that the relief valve shown in Fig. 4 and solenoid valve are realized, other are existing can realize that pressure controlled valve group is applicable to the present invention too, has just given an example no longer one by one here.
On the number of pressure controlled valve group, more pressure controlled valve group can realize than the control of multiple systems pressure, in other words, can realize the handoff procedure of multistage pressure by a plurality of pressure controlled valve groups are set, this just can guarantee the smooth running of system under more changeable load working condition.
In Fig. 4, relief valve all can the set pressure value, be used as the holding member of high pressure or low pressure by setting different force value, consider that the relief valve that is set as the lower pressure value will open under lower pressure, in order to realize control procedure accurately, second solenoid valve of need to connecting on relief valve, be the solenoid valve 5.4 in Fig. 4, this solenoid valve can cut out whole pressure controlled valve group by shut electromagnetic valve during higher than the setup pressure value of relief valve at system pressure.By contrast, be set as relief valve (relief valve 5.2 in Fig. 4) second solenoid valve of can connecting of maximum pressure value, second solenoid valve of also can not connecting, all can keep higher system pressure.
In the present embodiment, the high/low pressure cut-over valve group comprises by the proportional pressure control valve 5.3 of the input current pilot pressure linear change of linear change, and this proportional pressure control valve 5.3 has the input current of electromagnet coil Y3 of self and the characteristic of the proportional routine linear relationship of pilot pressure.Fig. 5 shows electric current and the pressure characteristic of proportional pressure control valve, can see at current value in the scope in about 23%-100%, is no matter that forward increases, and still oppositely reduces the increase of the proportional example of nominal pressure that it is corresponding or reduce.In other words, by the input current of linearity control proportional pressure control valve, just can make pilot pressure switch according to linear mode.
In Fig. 4, the high/low pressure cut-over valve group can also comprise first solenoid valve of connecting with proportional pressure control valve 5.3, and solenoid valve 5.5, and this solenoid valve is normally closed solenoid valve.Another kind of feasible mode is, solenoid valve 5.5 is not set, only the input current by control ratio relief valve 5.3 carries out the linearity switching between system pressure maintenance and different system force value, this mode is larger to the consumption of electromagnet, and there is certain leakage in proportional pressure control valve, system pressure keeps existing certain difficulty, therefore preferably use the normally closed solenoid valve of connecting with proportional pressure control valve, realize that with this valve pressure keeps function, and solenoid valve can realize that zero reveals, be beneficial to system pressure and keep.
The ratio pressure combined control valve that front is introduced is than liquid resistance throttling scheme of the prior art, not only can realize linearizing high low pressure handoff procedure, but also can realize the two-way switching of different pressures, bidirectional linear between any two kinds of force value of support multistage pressure value switches, thereby has realized the whole process control of pressure handoff procedure.Proportional pressure control valve hinders it than liquid does not have small damping, is subject to the oil contamination impact less, is not easy to result in blockage.
Logic control element group is not shown in Fig. 4, as a rule, these element groups can be realized by the logic controller of existing hardware, specifically, logic control element group can comprise that the electromagnet coil of controlling solenoid valve obtains the electromagnetic valve element and the proportional pressure control valve control unit of controlling the input current linear change of the electromagnet coil of proportional pressure control valve in the high/low pressure cut-over valve group of electric or dead electricity.
By the operation logic write in logic controller, can make all parts of ratio pressure combined control valve according to certain sequential and condition operation, realize the process of the linear switching of system pressure of expection.Utilize logic control element group and ratio pressure combined control valve can on control procedure, realize that parameter is controlled more accurately, the handoff procedure automation realizes, reduces on-the-spot debugging number of times, reduces assembling and debugging difficulty.
Each embodiment of the hydraulic system of introducing based on front, below provide an embodiment of hydraulic system pressure switching method of the present invention as shown in Figure 6.In this embodiment, the hydraulic system pressure switching flow comprises:
Electromagnetic valve element in step 102, described hydraulic system makes the electromagnet coil dead electricity of set pressure value lower than the solenoid valve in the pressure controlled valve group of described the first force value or the second force value;
In the present embodiment, the first force value can be higher than the second force value, also can be lower than the second force value, and the first force value and the second force value can be also any two force value in the multistage pressure value.Before switching, passing ratio relief valve control unit carrys out the input current of control ratio relief valve, makes it be controlled at identical with the first force value or, higher than the corresponding current value of the force value of the first force value, now system pressure is the first force value.
Next, solenoid valve for the set pressure value in the pressure controlled valve group lower than the first force value or the second force value, utilize the electromagnetic valve element to make these solenoid valve dead electricity, thereby close the corresponding pressure controlled valve group of these solenoid valves, avoid affecting the linear control process of proportional pressure control valve.
Finally, proportion of utilization relief valve control unit carrys out the input current of control ratio relief valve, makes its linear change to the corresponding current value of the second force value, like this system pressure also thereupon linear change to the second force value, thereby complete the pressure change procedure.
Take the hydraulic system shown in Fig. 4 as example, and in this figure, the high/low pressure cut-over valve group also comprises first solenoid valve of connecting with proportional pressure control valve 5.3, and solenoid valve 5.5, and the system pressure that solenoid valve 5.5 is responsible for the high/low pressure cut-over valve group keeps.The set pressure value of relief valve 5.1 is lower pressure value P 1, and the set pressure value of relief valve 5.2 is higher pressure value P 2.Under the stable state of lower system pressure P1, the coil of electromagnet Y1 obtains electric, and the coil of electromagnet Y2, Y3 must not be electric, and under the stable state of higher system pressure P2, the coil of electromagnet Y1, Y2, Y3 all must not electricity.
Current system pressure is higher system pressure P2, the process that is switched to lower system pressure P1 comprises: at the beginning of switching starts, at first the pilot pressure value that makes proportional pressure control valve 5.3 is the pressure value P 3(P3=P2+ Δ P that is slightly larger than P2), Δ P is absolute value, why use bigger force value, to consider that proportional pressure control valve 5.3 need to could start fully from power failure state higher than the force value of P2, before the input current of control ratio relief valve changes, also need the default time lag Δ t of time delay, this time lag Δ t is by dynamically to stable state, the required time is arranged according to proportional pressure control valve 5.3, after entering stable state, proportional pressure control valve 5.3 just can carry out linear control process, cross Cheng Qian at this, also need to make the coil of the electromagnet Y2 of solenoid valve 5.5 to obtain electric, open high low pressure control valve group, then the current value on the coil of the electromagnet Y3 by control ratio relief valve 5.3 is from the current value I corresponding with P3 3 linear change to the current value I 1 corresponding with P1, when the system pressure of hydraulic system reaches P1, make the solenoid valve in pressure controlled valve group that the set pressure value is P1 obtain electric, and after default time lag Δ t, make the equal dead electricity of electromagnet Y2 of electromagnet Y3 and the solenoid valve 5.5 of proportional pressure control valve 5.3, Y2 moves in advance than Y3, in order to avoid pressure surge.
Current system pressure is lower system pressure P1, and the process that is switched to higher system pressure P2 comprises: at the beginning of switching starts, the pilot pressure value that at first makes proportional pressure control valve 5.3 is the pressure value P 4(P4=P1+ Δ P that is slightly larger than P1), Δ P is absolute value.Before the input current of control ratio relief valve changes, also need the default time lag Δ t of time delay, after entering stable state, proportional pressure control valve 5.3 just can carry out linear control process, cross Cheng Qian at this, also need to make the coil of the electromagnet Y2 of solenoid valve 5.5 to obtain electric, make again the coil losing electricity of the electromagnet Y1 of solenoid valve 5.4, open high low pressure control valve group, then the current value on the coil of the electromagnet Y3 by control ratio relief valve 5.3 is from the current value I corresponding with P4 4 linear change to the current value I 2 corresponding with P2, when the system pressure of hydraulic system reaches P2, after default time lag Δ t, make the equal dead electricity of electromagnet Y2 of electromagnet Y3 and the solenoid valve 5.5 of proportional pressure control valve 5.3, Y2 moves in advance than Y3, in order to avoid pressure surge.
In sum, ratio pressure combined control valve provided by the present invention, hydraulic system and corresponding pressure switching method, than prior art, have the following advantages:
1, the switching of proportional pressure control valve control high low pressure is a linearization procedure, can avoid system shock fully; And can realize the linearity control of the two-way switching of high low pressure.Realized the manual control of mechanism's operation overall process.
2, exist without small damping in the ratio pressure combined control valve, affected by oil contamination less, be difficult for resulting in blockage.
3, the adoption rate relief valve carries out switching controls, and its design parameter is all accurate digitizing parameter, and handoff procedure is realized automatically by control program.Design parameter can accurately calculate, and has avoided scene repeatedly to debug, and has reduced assembling and debugging technique difficulty.
4, wherein wantonly two force value between all can the carry out linearity of ratio pressure combined control valve in multistage pressure switched.
Finally should be noted that: above embodiment is only in order to illustrate that technological scheme of the present invention is not intended to limit; Although with reference to preferred embodiment, the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can modify or the part technical characteristics is equal to replacement the specific embodiment of the present invention; And not breaking away from the spirit of technical solution of the present invention, it all should be encompassed in the middle of the technological scheme scope that the present invention asks for protection.
Claims (8)
1. a ratio pressure combined control valve, it is characterized in that, comprise: at least two pressure controlled valve groups and high/low pressure cut-over valve group, described at least two pressure controlled valve groups and high/low pressure cut-over valve group form relation in parallel, and described high/low pressure cut-over valve group comprises by the proportional pressure control valve of the input current pilot pressure linear change of linear change.
2. ratio pressure combined control valve according to claim 1, is characterized in that, described high/low pressure cut-over valve group also comprises first solenoid valve of connecting with described proportional pressure control valve, and described the first solenoid valve is normally closed solenoid valve.
3. ratio pressure combined control valve according to claim 1 and 2, it is characterized in that, but each pressure controlled valve group has the relief valve of set pressure value, the set pressure value also comprises second solenoid valve of connecting with described relief valve lower than the pressure controlled valve group of the highest set pressure value, and described the second solenoid valve is normally closed solenoid valve.
4. a hydraulic system, it is characterized in that, have the arbitrary described ratio pressure combined control valve of claim 1 ~ 3 and logic control element group, described logic control element group comprises: the electromagnet coil of controlling solenoid valve obtains the electromagnetic valve element and the proportional pressure control valve control unit of controlling the input current linear change of the electromagnet coil of proportional pressure control valve in the high/low pressure cut-over valve group of electric or dead electricity.
5. a hydraulic system pressure switching method, is characterized in that, comprising:
When the system pressure of hydraulic system is prepared to be switched to the second force value from the first force value, the proportional pressure control valve control unit in described hydraulic system is controlled at the input current of the proportional pressure control valve in the high/low pressure cut-over valve group and the corresponding current value of the force value that is not less than described the first force value;
Electromagnetic valve element in described hydraulic system makes the electromagnet coil dead electricity of set pressure value lower than the solenoid valve in the pressure controlled valve group of described the first force value or the second force value;
Described proportional pressure control valve control unit is controlled the input current linear change of described proportional pressure control valve to current value corresponding to described the second force value.
6. hydraulic system pressure switching method according to claim 5, it is characterized in that, if described high/low pressure cut-over valve group also comprises first solenoid valve of connecting with described proportional pressure control valve, when the system pressure of described hydraulic system is prepared to be switched to the second force value from the first force value, described proportional pressure control valve control unit is controlled at the input current of described proportional pressure control valve and the corresponding current value of the force value higher than described the first force value, and before the input current linear change of controlling described proportional pressure control valve, time delay Preset Time interval, and it is electric by described electromagnetic valve element, the electromagnet coil of described the first solenoid valve to be obtained.
7. hydraulic system pressure switching method according to claim 6, is characterized in that, described Preset Time interval according to described proportional pressure control valve by dynamically to the set of time of stable state.
8. hydraulic system pressure switching method according to claim 6, is characterized in that, when the system pressure of described hydraulic system is switched to described the second force value, makes proportional pressure control valve and the equal dead electricity of the first solenoid valve in described high/low pressure cut-over valve group.
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| CN201210154773.6A CN103423222B (en) | 2012-05-17 | 2012-05-17 | Ratio pressure combined control valve, hydraulic system and system pressure switching method |
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| CN201210154773.6A CN103423222B (en) | 2012-05-17 | 2012-05-17 | Ratio pressure combined control valve, hydraulic system and system pressure switching method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110211478A (en) * | 2019-04-24 | 2019-09-06 | 中广核核电运营有限公司 | A kind of hydraulic testing apparatus and test method |
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| CN102032306A (en) * | 2009-09-30 | 2011-04-27 | 萱场工业株式会社 | Hydraulic circuit for semi-active damper |
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| JPH0431672A (en) * | 1990-05-24 | 1992-02-03 | Tokimec Inc | Jointly supplying circuit for pump discharge oil |
| CN2168986Y (en) * | 1992-08-28 | 1994-06-15 | 孔繁华 | Normally closed multi-stage bralce |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110211478A (en) * | 2019-04-24 | 2019-09-06 | 中广核核电运营有限公司 | A kind of hydraulic testing apparatus and test method |
| CN110211478B (en) * | 2019-04-24 | 2021-08-27 | 中广核核电运营有限公司 | Hydraulic test device and test method |
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| CN103423222B (en) | 2015-12-16 |
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