CN116335911A - Two-stage high-pressure low-temperature liquid plunger pump - Google Patents
Two-stage high-pressure low-temperature liquid plunger pump Download PDFInfo
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- CN116335911A CN116335911A CN202111598293.4A CN202111598293A CN116335911A CN 116335911 A CN116335911 A CN 116335911A CN 202111598293 A CN202111598293 A CN 202111598293A CN 116335911 A CN116335911 A CN 116335911A
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- 239000007788 liquid Substances 0.000 title claims abstract description 233
- 230000007246 mechanism Effects 0.000 claims abstract description 16
- 230000009977 dual effect Effects 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 2
- 230000002000 scavenging effect Effects 0.000 description 9
- 238000013461 design Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000012530 fluid Substances 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000005184 irreversible process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
- 238000004260 weight control Methods 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B15/00—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
- F04B15/06—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts for liquids near their boiling point, e.g. under subnormal pressure
- F04B15/08—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts for liquids near their boiling point, e.g. under subnormal pressure the liquids having low boiling points
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
- F04B11/0008—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
- F04B11/0008—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators
- F04B11/0016—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators with a fluid spring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
- F04B11/0008—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators
- F04B11/0033—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators with a mechanical spring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B3/00—Machines or pumps with pistons coacting within one cylinder, e.g. multi-stage
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B15/00—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
- F04B15/06—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts for liquids near their boiling point, e.g. under subnormal pressure
- F04B15/08—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts for liquids near their boiling point, e.g. under subnormal pressure the liquids having low boiling points
- F04B2015/081—Liquefied gases
- F04B2015/0822—Hydrogen
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Details Of Reciprocating Pumps (AREA)
Abstract
The invention relates to a two-stage high-pressure low-temperature liquid plunger pump which comprises a driving part, a plunger rod, a middle pressure piston, a high pressure piston, a cylinder support, a middle pressure cylinder and a high pressure cylinder, wherein the middle pressure piston and the high pressure piston are internally provided with a middle pressure cavity and a low pressure back cavity, the high pressure piston is internally provided with a high pressure cavity, a low pressure liquid inlet channel is arranged between the low pressure back cavity and the middle pressure cavity, a middle pressure liquid inlet channel is arranged between the middle pressure cavity and the high pressure cavity, the high pressure cavity is also led out of a high pressure liquid outlet channel, the low pressure back cavity is communicated with external low-temperature liquid, the driving part is connected with the plunger rod and is used for driving the plunger rod to reciprocate up and down so as to drive the middle pressure piston and the high pressure piston to reciprocate up and down, the volumes of the middle pressure cavity and the high pressure cavity are changed to absorb liquid and discharge liquid, and the middle pressure cavity is provided with a pressure buffer mechanism. Compared with the prior art, the medium-pressure cavity is provided with the pressure buffer mechanism, so that peak high pressure can be restrained.
Description
Technical Field
The invention relates to a low-temperature liquid pump, in particular to a two-stage high-pressure low-temperature liquid plunger pump.
Background
The high-pressure low-temperature liquid plunger pump is used for pressurizing low-temperature liquid with low temperature and low pressure to high pressure. The cryogenic liquid may be liquid hydrogen, liquid nitrogen, or the like. The cryogenic liquid is typically pressurized from 0.1-0.3MPa to 70-90MPa. For example, the pressure is pressurized from 0.3MPa to 90MPa, and due to the existence of clearance volume between the piston and the cylinder, when the plunger returns, the pressure of the 90MPa low-temperature liquid in the clearance is firstly reduced to 0.3MPa, and then the liquid suction valve is opened. However, at high pressure, the low-temperature liquid has compressibility, and the low-temperature liquid also undergoes irreversible processes of heat absorption and heat release in the compression process, so that the high-pressure low-temperature liquid in the clearance is vaporized when the high-pressure piston retreats to absorb liquid, and occupies a part of the volume of the high-pressure cavity, and thus the high-pressure cavity cannot be fully used for absorbing liquid, and the volume coefficient is reduced. When the working condition is deteriorated, the high-pressure low-temperature liquid in the clearance expands and even occupies the whole high-pressure cavity, so that the flow is attenuated to zero, and the low-temperature liquid cannot be discharged. One solution is to apply a medium pressure stage piston and a medium pressure cylinder to the plunger rod to pressurize the low temperature liquid at low pressure to medium pressure, thereby causing the high pressure chamber to suck the low temperature liquid from medium pressure, thereby reducing the influence of clearance, however this method brings about the problem that the medium pressure chamber and the high pressure chamber are not matched in volume. When the volume of the medium pressure cavity is too small relative to the high pressure cavity, the flow is insufficient, and when the volume of the medium pressure cavity is too large relative to the high pressure cavity, peak high pressure can be generated, and the pump body is damaged.
Disclosure of Invention
Based on the problem that the high-pressure low-temperature liquid plunger pump in the prior art has peak high pressure, the invention provides a two-stage high-pressure low-temperature liquid plunger pump.
The invention changes the medium pressure cylinder with fixed scavenging volume into the variable scavenging volume by arranging the pressure buffer mechanism in the medium pressure cavity, thereby inhibiting peak high pressure.
The aim of the invention can be achieved by the following technical scheme:
the invention provides a two-stage high-pressure low-temperature liquid plunger pump, which comprises a driving part, a plunger rod, a middle-pressure piston, a high-pressure piston, a cylinder support, a middle-pressure cylinder and a high-pressure cylinder,
the cylinder support, the medium-pressure cylinder and the high-pressure cylinder are sequentially connected,
the plunger rod, the middle pressure piston and the high pressure piston are sequentially connected,
further, the plunger rod is connected with a high-pressure piston, the medium-pressure piston is connected with the outer side of the high-pressure piston,
the plunger rod is positioned in the cylinder support, the medium pressure piston is positioned in the medium pressure cylinder, the high pressure piston is positioned in the high pressure cylinder,
the medium pressure piston forms a medium pressure cavity and a low pressure back cavity in the medium pressure cylinder,
the high-pressure piston forms a high-pressure cavity in the high-pressure cylinder,
a low-pressure liquid inlet channel is arranged between the low-pressure back cavity and the medium-pressure cavity,
a medium pressure liquid inlet channel is arranged between the medium pressure cavity and the high pressure cavity,
the high-pressure cavity also leads out a high-pressure outlet channel,
the low pressure back cavity is communicated with external low temperature liquid,
the driving part is connected with the plunger rod and is used for driving the plunger rod to reciprocate up and down so as to drive the medium-pressure piston and the high-pressure piston to reciprocate up and down, so that the volumes of the medium-pressure cavity and the high-pressure cavity are changed to absorb and discharge liquid;
the medium pressure cavity is provided with a pressure buffer mechanism.
In one embodiment of the invention, the pressure buffer mechanism is a medium pressure piston support structure capable of effecting relative movement between the medium pressure piston and the high pressure piston; the medium pressure piston is connected to the outer side of the high pressure piston through a medium pressure piston supporting structure.
In one embodiment of the invention, the medium pressure piston support structure is selected to be a spring.
In one embodiment of the invention, the intermediate pressure piston support structure is selected to be a bellows, so that there is no leakage between the intermediate pressure piston and the high pressure piston.
Further, the bellows and the intermediate pressure piston may degrade into a membrane having elasticity. At high pressure, the diaphragm may deform, thereby making the medium pressure chamber volume variable, thereby suppressing high pressure spikes.
In one embodiment of the present invention, the pressure buffer mechanism is a pressure absorbing device connected to the medium pressure chamber. At this time, the middle pressure piston and the high pressure piston may be fixed without relative movement. The scavenging volume of the medium pressure chamber is changed by the pressure absorbing device so as to inhibit the high pressure spike.
In one embodiment of the invention, the pressure absorbing device consists of a suction cylinder, a suction piston and a suction piston spring, wherein the suction piston is positioned in the suction cylinder, the suction piston and the suction cylinder form a suction cavity, the suction cavity is connected with the medium-pressure cavity, one end of the suction piston spring is connected with the suction piston, and the other end of the suction piston spring is connected with the suction cylinder, so that the suction piston can reciprocate in the suction cylinder. When the pressure is high, the suction piston moves upwards, stabilizing the pressure. The weight of the suction piston spring and the suction piston can control the medium pressure.
When the length of the suction piston is long, the suction back cavity is degenerated to zero, and the spring can be fixed on the suction cylinder body by adopting a fixing device, so that the function of the suction back cavity is not affected.
In one embodiment of the present invention, when the length of the suction piston is not set to be long, the suction piston and the suction cylinder form a suction back cavity in addition to the suction cavity, and at this time, the suction piston spring is located in the suction back cavity and communicates the suction back cavity with the liquid storage tank, and the pressure of the suction back cavity is basically unchanged because the suction back cavity is communicated with the liquid storage tank. In one embodiment of the invention, a suction weight is provided on the suction piston. The high pressure of the medium pressure chamber can be controlled to be substantially constant by weight. The combination spring has a greater degree of freedom in design.
In one embodiment of the present invention, the pressure absorbing device is a pressure absorbing container with one closed end, and the internal volume is a pressure absorbing cavity. The working principle is that the wall of the pressure absorbing container expands after being pressed, and the volume of the pressure absorbing cavity increases, so that the pressure is stabilized. A relatively simple design is that the pressure absorbing vessel is a length of tubing that can be coiled to reduce the space occupation. And the tube wall is relatively thin so as to be easily expanded.
In one embodiment of the present invention, the pressure absorbing device is a pressure absorbing container formed of a bellows closed at one end, and the internal volume thereof is a pressure absorbing chamber. The working principle is that the wall of the pressure absorbing container expands after being pressed, and the volume of the pressure absorbing cavity increases, so that the pressure is stabilized.
In one embodiment of the invention, the low pressure liquid inlet channel comprises a low pressure liquid inlet and a low pressure liquid inlet valve, the low pressure liquid inlet is communicated with the low pressure back cavity and the medium pressure cavity, and the low pressure liquid inlet valve is arranged on the low pressure liquid inlet.
In one embodiment of the invention, the low-pressure liquid inlet is a channel which is arranged on the medium-pressure piston and is communicated with the low-pressure back cavity and the medium-pressure cavity, and the low-pressure liquid inlet is positioned in the medium-pressure cavity.
In one embodiment of the invention, the medium pressure liquid inlet channel comprises a medium pressure liquid inlet and a medium pressure liquid inlet valve, the medium pressure liquid inlet is communicated with the medium pressure cavity and the high pressure cavity, and the medium pressure liquid inlet valve is arranged on the medium pressure liquid inlet.
In one embodiment of the invention, the medium pressure liquid inlet is a channel which is arranged on the high pressure piston and is communicated with the medium pressure cavity and the high pressure cavity, and the medium pressure liquid inlet valve is positioned in the high pressure cavity.
In one embodiment of the invention, the high-pressure outlet channel comprises a high-pressure outlet, a high-pressure outlet valve, a high-pressure outlet pipe and a high-pressure piston outlet cavity,
the high-pressure piston liquid outlet cavity is formed in the cylinder head or the side wall of the high-pressure cylinder, the high-pressure liquid outlet is a channel formed in the high-pressure cylinder and communicated with the high-pressure cavity and the high-pressure piston liquid outlet cavity, the high-pressure liquid outlet valve is arranged on the high-pressure liquid outlet and located in the high-pressure piston liquid outlet cavity, and the high-pressure liquid outlet pipe is communicated with the high-pressure piston liquid outlet cavity and the outside.
In one embodiment of the invention, the low pressure inlet valve, medium pressure inlet valve, high pressure outlet valve is an automatic valve, selected as a spring-loaded valve, or the valve itself is a serpentine valve, or other form of valve.
In one embodiment of the invention, a plunger seal ring is provided between the plunger rod and the cylinder support. In one embodiment of the invention, the plunger seal ring is disposed on the plunger rod.
In one embodiment of the invention, a medium pressure piston ring is arranged between the medium pressure piston and the medium pressure cylinder. In one embodiment of the invention, the intermediate pressure piston ring is arranged on an intermediate pressure piston.
In one embodiment of the present invention, the piston ring may be single or multiple to reduce the leakage rate.
In one embodiment of the present invention, a high-pressure piston ring is provided between the high-pressure piston and the high-pressure cylinder. In one embodiment of the invention, the high pressure piston ring is disposed on a high pressure piston.
In one embodiment of the invention, a liquid storage tank is arranged outside the low-pressure back cavity and is communicated with the low-pressure back cavity, and the liquid storage tank stores low-temperature liquid.
In one embodiment of the invention, the liquid storage tank comprises a liquid storage tank outlet and a liquid storage tank inlet, wherein the liquid storage tank outlet is arranged above, the liquid storage tank inlet is arranged below, and the liquid level of the liquid storage tank is higher than a channel communicated between the liquid storage tank and the low-pressure back cavity.
In one embodiment of the invention, the liquid storage tank pre-stores liquid from a low-temperature liquid storage tank, and a vacuum cover is arranged outside the liquid storage tank.
In one embodiment of the invention, the cryogenic liquid is selected to be liquid hydrogen.
The working principle of the invention is as follows: the driving part drives the plunger rod to reciprocate up and down so as to drive the medium-pressure piston and the high-pressure piston to reciprocate up and down, and the volumes of the medium-pressure cavity and the high-pressure cavity are changed so as to absorb and discharge liquid.
When the plunger rod moves downwards, the low-pressure liquid inlet valve is opened, the medium-pressure liquid inlet valve is closed, and the high-pressure liquid outlet valve is opened; the high-pressure liquid flows out of the high-pressure liquid outlet pipe through the high-pressure liquid outlet and the high-pressure liquid outlet valve; the low-pressure liquid flows into the medium-pressure cavity from the low-pressure back cavity through the low-pressure liquid inlet and the low-pressure liquid inlet valve.
When the plunger rod moves upwards, the low-pressure liquid inlet valve is closed, the medium-pressure liquid inlet valve is opened, and the high-pressure liquid outlet valve is closed; medium-pressure liquid in the medium-pressure cavity enters the high-pressure cavity through the medium-pressure liquid inlet and the medium-pressure liquid inlet valve; low pressure liquid enters the low pressure back chamber from the reservoir.
The medium pressure chamber is provided with the pressure buffer mechanism, the principle is that the medium pressure cylinder with fixed scavenging volume is changed into the medium pressure cylinder with variable scavenging volume, the pressure buffer mechanism can be realized by the relative movement between the medium pressure piston and the high pressure piston, the pressure buffer mechanism can also be used for adding the buffer chamber (namely the pressure absorbing device in the invention) into the medium pressure chamber, the purpose of adding the buffer chamber is to ensure that the medium pressure piston is not moved, and the movement of the medium pressure piston is a key component, so that the requirement on the structure setting is actually high, and the buffer chamber is added into the medium pressure chamber more easily.
Compared with the prior art, the invention has the following advantages:
1. the middle pressure cavity is provided with the pressure buffer mechanism, one mode is that the middle pressure piston is connected to the outer side of the high pressure piston through the middle pressure piston supporting structure, the middle pressure piston and the high pressure piston can move relatively, if the pressure is too high, the middle pressure piston and the high pressure piston move relatively a bit, so that the instantaneous high pressure is inhibited to a certain extent, and after the instantaneous high pressure is reached, the middle pressure piston supporting structure can also adjust the existing position between the middle pressure piston and the high pressure piston back to the original balance position, so that the peak high pressure is inhibited.
2. In some embodiments of the invention, the pressure buffer mechanism is selected to provide access to the medium pressure chamber with a pressure absorbing device, in which case the medium pressure piston and the high pressure piston may be fixed without relative movement. The scavenging volume of the medium pressure chamber is changed by the pressure absorbing device so as to inhibit the high pressure spike.
Drawings
FIG. 1 is a schematic diagram of a two-stage high-pressure low-temperature liquid plunger pump in embodiment 1;
FIG. 2 is a schematic diagram of a two-stage high-pressure low-temperature liquid plunger pump in embodiment 2;
FIG. 3 is a schematic diagram of a two-stage high-pressure low-temperature liquid plunger pump in embodiment 3;
FIG. 4 is a schematic diagram of a dual-stage high-pressure low-temperature liquid plunger pump in embodiment 4;
FIG. 5 is a schematic diagram of a two-stage high-pressure low-temperature liquid plunger pump in embodiment 5;
fig. 6 is a schematic view showing the combined structure of the suction piston and the suction weight in example 6.
The reference numerals in the figures indicate:
1. a driving part, a driving part and a driving part,
21. plunger rods, 211, plunger seal rings,
22. a medium pressure piston 221, a medium pressure piston ring 222, a spring 222a, a corrugated pipe 223, a low pressure liquid inlet valve 224, a low pressure liquid inlet,
23. a high-pressure piston 231, a high-pressure piston ring 232, a medium-pressure liquid inlet 233 and a medium-pressure liquid inlet valve,
31. the cylinder is supported by the cylinder,
32. a middle pressure cylinder 321, a middle pressure cavity 322, a low pressure back cavity,
33. a high-pressure cylinder 331, a high-pressure cavity 332, a high-pressure liquid outlet 333, a high-pressure liquid outlet valve 334, a high-pressure liquid outlet pipe 335, a high-pressure piston liquid outlet cavity,
41. a liquid storage tank, 411, a liquid storage tank outlet, 412, a liquid level, 413, a liquid storage tank inlet,
5. a vacuum cover is arranged on the vacuum cover,
61. the pressure absorbing chamber 61a, the pressure absorbing chamber 61b, the pressure absorbing chamber 62, the pressure absorbing cylinder 62a, the pressure absorbing container 62b, the pressure absorbing container 63, the pressure absorbing piston 64, the pressure absorbing piston spring 65, the pressure absorbing back chamber 66 and the pressure absorbing weight.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples.
Example 1
The embodiment provides a two-stage high-pressure low-temperature liquid plunger pump, and the structure is shown in fig. 1.
The two-stage high-pressure low-temperature liquid plunger pump provided by the embodiment comprises a driving part 1, a plunger rod 21, a middle pressure piston 22, a high pressure piston 23, a cylinder support 31, a middle pressure cylinder 32, a high pressure cylinder 33 and a liquid storage tank 4,
the cylinder support 31, the middle pressure cylinder 32, and the high pressure cylinder 33 are sequentially connected,
the plunger rod 21, the middle pressure piston 22 and the high pressure piston 23 are sequentially connected,
specifically, the plunger rod 21 is connected with a high-pressure piston 23, the middle-pressure piston 22 is connected outside the high-pressure piston 23, and the middle-pressure piston 22 and the high-pressure piston 23 can move relatively,
the plunger rod 21 is located in the cylinder support 31, the intermediate pressure piston 22 is located in the intermediate pressure cylinder 32, the high pressure piston 23 is located in the high pressure cylinder 33,
the intermediate pressure piston 22 forms an intermediate pressure chamber 321 and a low pressure back chamber 322 within the intermediate pressure cylinder 32,
the high-pressure piston 22 forms a high-pressure chamber 331 in the high-pressure cylinder 33,
the liquid storage tank 4 is located outside the low-pressure back cavity 322, and the liquid storage tank 4 is communicated with the low-pressure back cavity 322, the liquid storage tank 41 pre-stores low-temperature liquid,
a low-pressure liquid inlet channel is arranged between the low-pressure back cavity 322 and the medium-pressure cavity 321,
a medium pressure liquid inlet channel is arranged between the medium pressure cavity 321 and the high pressure cavity 331,
the high pressure chamber 331 also leads out a high pressure outlet channel,
the driving part 1 is connected with the plunger rod 21, and is used for driving the plunger rod 21 to reciprocate up and down, so as to drive the middle pressure piston 22 and the high pressure piston 23 to reciprocate up and down, and the volumes of the middle pressure cavity 321 and the high pressure cavity 331 are changed, so that liquid can be sucked and discharged.
In this embodiment, the low pressure liquid inlet channel includes a low pressure liquid inlet 224 and a low pressure liquid inlet valve 223, the low pressure liquid inlet 224 is communicated with a low pressure back cavity 322 and a medium pressure cavity 321, and the low pressure liquid inlet valve 223 is disposed on the low pressure liquid inlet 224.
In this embodiment, the low pressure inlet 224 is a channel formed on the middle pressure piston 22 and communicating the low pressure back chamber 322 and the middle pressure chamber 321, and the low pressure inlet valve 223 is located in the middle pressure chamber 321.
In this embodiment, the medium pressure liquid inlet channel includes a medium pressure liquid inlet 232 and a medium pressure liquid inlet valve 233, the medium pressure liquid inlet 232 communicates with the medium pressure cavity 321 and the high pressure cavity 331, and the medium pressure liquid inlet valve 233 is disposed on the medium pressure liquid inlet 232.
In this embodiment, the medium pressure inlet 232 is a channel formed on the high pressure piston 23 and communicating the medium pressure chamber 321 and the high pressure chamber 331, and the medium pressure inlet valve 233 is located in the high pressure chamber 331.
In this embodiment, the high-pressure liquid outlet channel includes a high-pressure liquid outlet 332, a high-pressure liquid outlet valve 333, a high-pressure liquid outlet pipe 334 and a high-pressure piston liquid outlet cavity 335, the high-pressure piston liquid outlet cavity 335 is formed at a cylinder head or a side wall of the high-pressure cylinder 33, the high-pressure liquid outlet 332 is a channel formed at the cylinder head of the high-pressure cylinder 33 and communicated with the high-pressure cavity 331 and the high-pressure piston liquid outlet cavity 335, the high-pressure liquid outlet valve 333 is disposed on the high-pressure liquid outlet 332 and is located in the high-pressure piston liquid outlet cavity 335, and the high-pressure liquid outlet pipe 334 is communicated with the high-pressure piston liquid outlet cavity 335 and the outside.
In this embodiment, the low pressure inlet valve 223, the medium pressure inlet valve 233, and the high pressure outlet valve 333 are automatic valves, or valves selected to be pressed by springs, or valves themselves are serpentine valves, or other types of valves.
In this embodiment, a plunger seal ring 211 is provided between the plunger rod 21 and the cylinder support 31. In this embodiment, the plunger seal ring 211 is provided on the plunger rod 21.
In this embodiment, a middle pressure piston ring 221 is disposed between the middle pressure piston 22 and the middle pressure cylinder 32. In this embodiment, the intermediate pressure piston ring 221 is disposed on the intermediate pressure piston 22.
In this embodiment, a high-pressure piston ring 231 is disposed between the high-pressure piston 23 and the high-pressure cylinder 33. In this embodiment, the high-pressure piston ring 231 is disposed on the high-pressure piston 23.
In this embodiment, the middle pressure piston 22 is connected to the outside of the high pressure piston 23 through a middle pressure piston support structure.
In this embodiment, the medium pressure piston support structure is selected to be a spring 222.
In this embodiment, the piston ring may be single or multiple to reduce the leakage rate.
In this embodiment, the liquid tank 41 includes a liquid tank outlet 411 and a liquid tank inlet 413, the liquid tank outlet 411 is disposed above, the liquid tank inlet 413 is disposed below, and the liquid level 412 of the liquid tank 41 is higher than the channel communicating between the liquid tank 4 and the low-pressure back cavity 322.
In this embodiment, the liquid tank 41 pre-stores the liquid from the low-temperature liquid storage tank, and the vacuum cover 5 is further arranged on the outer side of the liquid tank 41.
In this embodiment, the liquid may be entirely contained in the liquid storage tank 41.
In this embodiment, the liquid storage tank 41 may be omitted or reduced to a channel, and the cryogenic liquid is directly supplied from the outside, but the structure is simplified although the buffer is absent.
In this embodiment, the vacuum enclosure 5 may be omitted if the pump is placed in a reservoir.
In this embodiment, liquid hydrogen is used as the cryogenic liquid.
In this embodiment, in operation, the driving part 1 drives the plunger rod 21 to reciprocate up and down, so as to drive the middle pressure piston 22 and the high pressure piston 23 to reciprocate up and down, so that the volumes of the middle pressure chamber 321 and the high pressure chamber 331 are changed to suck and discharge liquid.
When the plunger rod 21 moves downward, the low-pressure liquid inlet valve 223 is opened, the medium-pressure liquid inlet valve 233 is closed, and the high-pressure liquid outlet valve 333 is opened; the high-pressure liquid flows out from the high-pressure liquid outlet pipe 334 through the high-pressure liquid outlet 332 and the high-pressure liquid outlet valve 333; low pressure fluid flows from low pressure back chamber 322 through low pressure inlet 224 and low pressure inlet valve 223 into medium pressure chamber 321.
When the plunger rod 21 moves upward, the low-pressure liquid inlet valve 223 is closed, the medium-pressure liquid inlet valve 233 is opened, and the high-pressure liquid outlet valve 333 is closed; medium pressure liquid in the medium pressure cavity 321 enters the high pressure cavity 331 through the medium pressure liquid inlet 232 and the medium pressure liquid inlet valve 233; low pressure liquid enters the low pressure back chamber 321 from the reservoir 41.
The closing and opening of the valve during the above process may be retarded or advanced somewhat from the up and down movement of the plunger.
Since the low temperature fluid is compressible under high pressure, when the plunger rod 21 moves upward, the middle pressure piston 22 and the high pressure piston 23 move upward, and the residual fluid in the clearance of the high pressure chamber 331 is expanded, so that the middle pressure inlet valve 233 cannot be opened immediately, but the fluid in the middle pressure chamber 321 is in a low pressure state and is basically incompressible, so that the pressure may rise to be balanced with the pressure of the high pressure chamber 331, and thus an instantaneous pressure spike may occur. While the design pressure of the medium pressure chamber 321 is low in order to provide sub-cooled liquid to the high pressure chamber 331. The pressure spike thus not only increases the instantaneous force of the drive section, but also causes the intermediate pressure chamber to have an instantaneous high pressure. This can cause transient overloads and even damage to the machine.
In order to prevent the instantaneous high pressure, in this embodiment, the middle pressure piston 22 and the high pressure piston 23 can move relatively, and are connected through the spring 222, if the pressure is too high, the middle pressure piston 22 overcomes the elasticity of the spring 222 and moves relatively to the high pressure piston 23 a little, so that the instantaneous high pressure is restrained to a certain extent. After the instantaneous high pressure is reached, the spring again adjusts the current position between the medium pressure piston and the high pressure piston back to the original equilibrium position.
Since the amount of relative movement between the intermediate pressure piston 22 and the high pressure piston 23 is not large, the gap between the two may be small, the amount of leakage may be small, and a seal ring may not be provided, or a seal ring may be provided.
The principle of this embodiment is that the relative movement between the intermediate pressure piston 22 and the high pressure piston 23 changes the intermediate pressure chamber from the original fixed scavenging volume to the variable scavenging volume, thereby suppressing the peak high pressure.
In this embodiment, the medium pressure piston that is movable relative to the high pressure piston may be regarded as a pressure buffer mechanism.
In this embodiment, the high pressure piston part which is sleeved with the medium pressure piston can also be regarded as a part of the plunger rod, and the high pressure piston and the plunger rod are integrated to facilitate processing from the processing point of view. Thus, the high pressure piston is not clearly defined with the plunger rod, the upper part can be called the plunger rod, and the lower part can be called the high pressure piston.
Example 2
Referring to fig. 2, another dual-stage high-pressure low-temperature liquid plunger pump is provided in this embodiment.
The difference from embodiment 1 is that in this embodiment, a bellows 222a is used instead of the spring 222 in embodiment 1, so that there is no leakage between the medium pressure piston 22 and the high pressure piston 23.
Further, the bellows and the intermediate pressure piston may degrade into a membrane having elasticity. At high pressure, the diaphragm may deform, thereby making the medium pressure chamber volume variable, thereby suppressing high pressure spikes.
Example 3
Referring to fig. 3, another dual stage high pressure low temperature liquid plunger pump is provided in this embodiment.
The difference from embodiments 1 and 2 is that in this embodiment, the medium pressure piston support structure is not provided, but the pressure absorbing device is connected to the medium pressure chamber 321. At this time, the middle pressure piston and the high pressure piston may be fixed without relative movement. The scavenging volume of the medium pressure chamber is changed by the pressure absorbing device so as to inhibit the high pressure spike.
The pressure absorbing device is composed of a suction cylinder 62, a suction piston 63 and a suction piston spring 64, the suction piston 63 is located in the suction cylinder 62, the suction piston 63 and the suction cylinder 62 form a suction cavity 61 and a suction back cavity 65, the suction cavity 61 is connected with the medium pressure cavity 321, the suction back cavity 65 is communicated with the liquid storage tank 41, the suction piston spring 64 is located in the suction back cavity 65, one end of the suction piston spring 64 is connected with the suction piston 63, and the other end of the suction piston spring 64 is connected with the suction cylinder 62, so that the suction piston 63 can reciprocate in the suction cylinder 62.
When the pressure is high, the suction piston 63 moves upward, stabilizing the pressure. Since the suction back chamber 65 communicates with the liquid reservoir 41, the pressure thereof is substantially unchanged. The suction piston spring 64 and the suction piston weight control the medium pressure.
When the length of the suction piston is long, the suction back cavity is degenerated to zero, and the spring can be fixed on the suction cylinder body by adopting a fixing device, so that the function of the suction back cavity is not affected.
In some more specific embodiments of this example, the suction piston 63 may be provided with a piston ring to control the leakage amount, and if the displacement is small, the gap between the suction cylinder 62 and the suction piston 63 may be small, the leakage amount may be small, and the piston ring may not be provided.
Compared with the embodiment 1, the pressure absorbing mechanism is additionally arranged, the medium-pressure piston and the high-pressure piston can be fixed together or integrally manufactured, and do not do relative motion, so that the reliability is high and the cost is low. Further, the plunger rod, the intermediate pressure piston and the high pressure piston may be integrally formed such that the upper portion is referred to as the plunger rod, the middle portion is referred to as the intermediate pressure piston, and the lower portion is referred to as the high pressure piston, or simply the piston.
Example 4
Referring to fig. 4, another dual stage high pressure low temperature liquid plunger pump is provided in this embodiment.
The difference from embodiment 3 is that in this embodiment, the pressure absorbing means is a pressure absorbing vessel 62a closed at one end and the internal volume thereof is a pressure absorbing chamber 61a.
The working principle is that the wall of the pressure absorbing container 62a expands after being pressed, and the volume of the pressure absorbing cavity 61a increases, thereby stabilizing the pressure.
One relatively simple design is that the pressure absorbing vessel 62a is a length of tubing that can be coiled to reduce the space occupation. And the tube wall is relatively thin so as to be easily expanded.
Example 5
Referring to fig. 5, another dual stage high pressure low temperature liquid plunger pump is provided in this embodiment.
The point of difference from embodiment 3 is that, in this embodiment,
the pressure absorbing means is a pressure absorbing vessel 62b formed of a bellows closed at one end, and the internal volume thereof is a pressure absorbing chamber 61b.
The working principle is that the wall of the pressure absorbing container 62b expands after being pressed, and the volume of the pressure absorbing chamber 61b increases, thereby stabilizing the pressure.
The bellows is more easily expanded and occupies a smaller volume than in example 4 shown in fig. 4.
Example 6
Referring to fig. 5, another dual stage high pressure low temperature liquid plunger pump is provided in this embodiment.
In this embodiment, a suction weight 66 is provided on the suction piston 63, which is different from embodiment 3.
While the pressure of the pressure absorbing device of embodiment 3 shown in fig. 3 is hardly set to a fixed value, such as 0.6MPa, 0.8MPa, or the like, due to the influence of the spring property, the present embodiment provides a suction weight 66 on the suction piston 63, and the high pressure of the medium pressure chamber can be controlled to be substantially constant by the reliable weight. The combination spring has a greater degree of freedom in design.
The liquid inlet and outlet positions of the embodiment of the invention are not limited to the embodiment positions, and only need to be the same as the cylinder.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present invention.
The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.
Claims (10)
1. A two-stage high-pressure low-temperature liquid plunger pump comprises a driving part (1), a plunger rod (21), a middle-pressure piston (22), a high-pressure piston (23), a cylinder support (31), a middle-pressure cylinder (32) and a high-pressure cylinder (33),
the cylinder support (31), the middle pressure cylinder (32) and the high pressure cylinder (33) are sequentially connected,
the plunger rod (21), the middle pressure piston (22) and the high pressure piston (23) are sequentially connected,
the plunger rod (21) is positioned in the cylinder support (31), the medium-pressure piston (22) is positioned in the medium-pressure cylinder (32), the high-pressure piston (23) is positioned in the high-pressure cylinder (33),
the middle pressure piston (22) forms a middle pressure cavity (321) and a low pressure back cavity (322) in the middle pressure cylinder (32),
the high-pressure piston (22) forms a high-pressure cavity (331) in the high-pressure cylinder (33),
a low-pressure liquid inlet channel is arranged between the low-pressure back cavity (322) and the medium-pressure cavity (321),
a medium-pressure liquid inlet channel is arranged between the medium-pressure cavity (321) and the high-pressure cavity (331),
the high-pressure cavity (331) also leads out a high-pressure outlet channel,
the low pressure back chamber (322) is in communication with an external cryogenic liquid,
the driving part (1) is connected with the plunger rod (21) and is used for driving the plunger rod (21) to reciprocate up and down so as to drive the middle pressure piston (22) and the high pressure piston (23) to reciprocate up and down, so that the volumes of the middle pressure cavity (321) and the high pressure cavity (331) are changed to absorb and discharge liquid,
the device is characterized in that the medium pressure cavity (321) is provided with a pressure buffer mechanism.
2. The two-stage high-pressure low-temperature liquid plunger pump according to claim 1, wherein,
the pressure buffer mechanism is a medium-pressure piston supporting structure capable of realizing relative movement between the medium-pressure piston (22) and the high-pressure piston (23);
the medium-pressure piston (22) is connected to the outer side of the high-pressure piston (23) through a medium-pressure piston supporting structure.
3. The dual stage high pressure cryogenic liquid plunger pump of claim 2, wherein the intermediate pressure piston support structure is selected as a spring (222) or as a bellows (222 a).
4. The two-stage high-pressure low-temperature liquid plunger pump according to claim 1, wherein,
the pressure buffer mechanism is a pressure absorbing device connected with the medium pressure cavity (321).
5. The two-stage high-pressure low-temperature liquid plunger pump according to claim 4, wherein the pressure absorbing device consists of a suction cylinder (62), a suction piston (63) and a suction piston spring (64), the suction piston (63) is positioned in the suction cylinder (62), the suction piston (63) and the suction cylinder (62) form a suction cavity (61), the suction cavity (61) is connected with the medium-pressure cavity (321), one end of the suction piston spring (64) is connected with the suction piston (63), and the other end of the suction piston spring is connected with the suction cylinder (62), so that the suction piston (63) can reciprocate in the suction cylinder (62).
6. The two-stage high-pressure low-temperature liquid plunger pump according to claim 5, wherein a suction weight (66) is provided on the suction piston (63).
7. The two-stage high-pressure low-temperature liquid plunger pump according to claim 4, wherein the pressure absorbing device is a pressure absorbing container (62 a) with one closed end, and the internal volume thereof is a pressure absorbing cavity (61 a).
8. The two-stage high pressure low temperature liquid plunger pump according to claim 4, wherein said pressure absorbing means is a pressure absorbing container (62 b) formed of a bellows closed at one end, and the internal volume thereof is a pressure absorbing chamber (61 b).
9. The two-stage high-pressure low-temperature liquid plunger pump according to claim 1, wherein,
the outside of low pressure back chamber (322) is provided with liquid reserve tank (4), just liquid reserve tank (4) are linked together with low pressure back chamber (322), and liquid reserve tank (41) store low temperature liquid.
10. The two-stage high-pressure low-temperature liquid plunger pump according to claim 1, wherein the low-pressure liquid inlet channel comprises a low-pressure liquid inlet (224) and a low-pressure liquid inlet valve (223), the low-pressure liquid inlet (224) is communicated with a low-pressure back cavity (322) and a medium-pressure cavity (321), and the low-pressure liquid inlet valve (223) is arranged on the low-pressure liquid inlet (224);
the medium-pressure liquid inlet channel comprises a medium-pressure liquid inlet (232) and a medium-pressure liquid inlet valve (233), the medium-pressure liquid inlet (232) is communicated with the medium-pressure cavity (321) and the high-pressure cavity (331), and the medium-pressure liquid inlet valve (233) is arranged on the medium-pressure liquid inlet (232);
the high-pressure liquid outlet channel comprises a high-pressure liquid outlet (332), a high-pressure liquid outlet valve (333), a high-pressure liquid outlet pipe (334) and a high-pressure piston liquid outlet cavity (335), the high-pressure piston liquid outlet cavity (335) is formed in the cylinder head or the side wall of the high-pressure cylinder (33), the high-pressure liquid outlet (332) is a channel which is formed in the high-pressure cylinder (33) and is communicated with the high-pressure cavity (331) and the high-pressure piston liquid outlet cavity (335), the high-pressure liquid outlet valve (333) is arranged on the high-pressure liquid outlet (332) and is located in the high-pressure piston liquid outlet cavity (335), and the high-pressure liquid outlet pipe (334) is communicated with the high-pressure piston liquid outlet cavity (335) and the outside.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111598293.4A CN116335911A (en) | 2021-12-24 | 2021-12-24 | Two-stage high-pressure low-temperature liquid plunger pump |
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| CN202111598293.4A CN116335911A (en) | 2021-12-24 | 2021-12-24 | Two-stage high-pressure low-temperature liquid plunger pump |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117662451A (en) * | 2023-11-27 | 2024-03-08 | 烟台东德氢能技术有限公司 | Submerged type cold insulation method of high-pressure liquid hydrogen pump |
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2021
- 2021-12-24 CN CN202111598293.4A patent/CN116335911A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117662451A (en) * | 2023-11-27 | 2024-03-08 | 烟台东德氢能技术有限公司 | Submerged type cold insulation method of high-pressure liquid hydrogen pump |
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