CN111237286A

CN111237286A - Isolated fluid pressure conversion device with linked hydraulic bag and piston

Info

Publication number: CN111237286A
Application number: CN202010130804.9A
Authority: CN
Inventors: 张永利
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2020-06-05

Abstract

The invention discloses a fluid pressure conversion device, which comprises a cylinder body (1), a piston (2) and a hydraulic bag (3), wherein the hydraulic bag (3) is a pressure-bearing tensile tubular soft bag capable of expanding and contracting, and is arranged in the cylinder body (1), bag nozzles (32) at two ends are embedded into mounting holes in the centers of the piston (2) and a cylinder cover (12) and are tightly connected, and a space in a cylinder barrel (11) is isolated into a bag inner cavity (4) and a bag outer cavity (5) by the bag body (31), so that two different fluids are respectively contained, and channels for the fluid media to enter and exit are respectively arranged. When the pressure-adjustable fluid pressure-adjustable valve works, the pressure or the volume of fluid in one cavity is actively changed, namely the pressure or the volume of fluid in the other cavity is correspondingly changed through the combined action of expansion, contraction and extension of the bag body (31) and sliding of the piston (2), and the pressure change in the bag inner cavity (4) is larger than that in the bag outer cavity (5), and the volume change is small. The device can be used for pressurization transmission, material pumping, pipeline pressure regulation and the like.

Description

Isolated fluid pressure conversion device with linked hydraulic bag and piston

Technical Field

The invention relates to the technical field of hydraulic, pneumatic and variable-capacity fluid pumps, in particular to an isolated fluid pressure conversion device with a hydraulic bag and a piston linked.

Background

In many industrial scenarios involving fluid pressure transmission or fluid material transport, techniques and apparatus for driving one fluid with pressure energy against another fluid have been widely used, with more typical applications including:

1. supercharging transmission, such as a gas-liquid supercharging cylinder in hydraulic machinery, a hydraulic water expansion machine used for rock excavation or internal pressure forming processing and the like;

2. pumping and lifting, such as pumping oil by using water pressure or discharging slurry from the underground to the ground in the oil extraction and mining industries;

3. filter pressing and permeating, for example, in the seawater desalination, the filtered water is pressurized by seawater pressure to carry out reverse osmosis to remove salt and the like;

4. energy storage compensation, such as a bag type compressed air accumulator, a piston type energy accumulator, a pressure compensator and the like;

5. compressing phase change, e.g. LNG, liquid CO₂The compression preparation of (3), a pressure exchange type refrigeration compressor and the like.

These devices are essentially fluid pressure conversion devices, and all have a process of transferring pressure energy between different fluids in one way or in mutual during operation. Users generally expect the apparatus to provide a large transfer pressure differential, to incur less energy loss, and to ensure tight isolation between the pressure medium and the feed fluid without contaminating the same. In the prior art, isolated fluid pressure conversion is usually realized by two modes, one is that piston groups with different diameters are adopted, and the device has the advantage of realizing higher pressure-increasing multiple and output pressure, for example, a gas-liquid pressure cylinder with hundred-MPa output is provided by multiple manufacturers at home and abroad at present. However, the multi-piston structure increases inertia of moving parts and friction with the cylinder wall, thereby causing problems of response slowness and increased power consumption, and the sliding gap between the piston and the cylinder makes it difficult to avoid mixing of media. And secondly, as diaphragm pumps, bellows pumps, bag type energy accumulators and the like are adopted, the diaphragm and bag type flexible parts are adopted, the advantage is that strict isolation among different media can be realized, but the conventional flexible parts have low self-bearing anti-cracking strength and are difficult to adapt to high internal and external pressure difference, and the equipment with the working pressure of over ten megapascals is extremely rare at present.

The inventor of the present invention has disclosed a tubular hydraulic bladder and a pressure generating device in the domestic patent document CN 110566533 a, in the technical scheme, the "tubular hydraulic bladder" provided in the present invention has a bladder wall made of elastic synthetic rubber sandwiched with a reinforcing layer, and the reinforcing layer is made of high-strength high-modulus fiber bundles such as para-aramid, ultra-high molecular polyethylene, etc. which are obliquely and densely woven, so that the bladder body has far superior comprehensive advantages of a common bladder and a hydraulic hose in terms of two performances which are originally contradictory in pressure bearing and expansion and contraction.

The tubular hydraulic capsule is proved to have the following advantages through the actual measurement and practical inspection of products: firstly, the pressure is high, the capsule body can reliably bear the pressure in a sealing way for water, oil and gas, and the minimum bursting pressure in a free state can reach more than 70 MPa; secondly, the tensile strength is high, and the bag body and the connection between the bag body and the bag mouths at the two ends can bear the tensile force of several tons or even tens of tons (different according to the model); and thirdly, the diameter change is more than 3 times, the length change is more than 1.6 times, and the change of the internal volume of the balloon is more than 5 times when the same balloon is expanded to the thickest and shortest and compared with the two states when the same balloon is stretched to the thinnest and shortest. In addition, it has some advantages common to general flexible devices, such as light weight, low cost, good durability, etc. In summary, the emergence of such new technical products provides a new feasible idea for the technical improvement of the isolated fluid pressure conversion device.

Disclosure of Invention

The invention aims to provide a fluid pressure conversion device to solve the problems of incomplete medium isolation, large energy loss, heavy equipment and the like when the pressure conversion of two fluid media is realized in the prior art. The device is suitable for a boosting transmission device of hydraulic and pneumatic mechanical equipment, and can also be used for material pumping or pressure regulating equipment in a high-pressure fluid conveying pipeline, such as: superchargers, booster pumps, compressors or accumulators, etc.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides an isolated fluid pressure conversion device with a hydraulic bag and a piston linked. The cylinder body is a rigid shell and comprises a cylinder barrel and a cylinder cover arranged at the end part of the cylinder barrel; the piston is an armless piston with the diameter matched with the cylinder barrel and is installed in the cylinder barrel in a sliding mode, and the centers of the cylinder cover and the piston body are both provided with axially-through installation holes; the hydraulic bag is composed of a bag body and a bag mouth, the bag body is a pressure-bearing tensile tubular soft bag, the inner layer and the outer layer of the bag body are elastic synthetic rubber anti-seepage layers, the middle layer is a reinforced layer formed by obliquely and crossly weaving and winding synthetic fiber bundles or thin steel wires, and the diameter and the length of the reinforced layer can expand, contract and stretch within a certain range along with the change of the pressure difference between the inside and the outside and the stress at two ends; the bag mouth is a metal connecting piece arranged at the end part of the bag body and used for locking and sealing the bag mouth and assembling and connecting with other parts.

The hydraulic bag is arranged between the cylinder cover and the piston in the cylinder barrel, and bag nozzles at two ends of the hydraulic bag are respectively embedded into mounting holes in the centers of the cylinder cover and the piston to form a tight and sealed connection; the cylindrical space between the piston in the cylinder barrel and the cylinder cover is isolated into a bag inner cavity and a bag outer cavity by the bag body, and the bag inner cavity and the bag outer cavity are respectively used for containing two media of a first fluid and a second fluid. When the variable-pressure dual-purpose bladder works, as long as the pressure or the volume of the fluid in any one of the chambers is actively changed, the pressure or the volume of the fluid in the other chamber is correspondingly and passively changed through the combined action of the expansion, contraction and extension of the bladder body and the sliding of the piston, the variable quantity of the fluid pressure in the bladder inner chamber is larger than the variable quantity of the fluid pressure in the bladder outer chamber, and the variable quantity of the bladder outer chamber volume is larger than the variable quantity of the bladder inner chamber volume.

The working principle is as follows: for ease of description, fluid a and fluid B will be referred to hereinafter as the first fluid in the balloon interior chamber and the second fluid in the balloon exterior chamber, respectively. The pressure P of the fluid A when the capsule and piston in the cylinder are temporarily in a state of static equilibrium_AGreater than pressure P of fluid B_BThe reason is that the fluid B in the outer bag cavity obeys Pascal's law, and in addition to transmitting the pressure to the fluid A equally through the flexible bag wall surrounded by the fluid B, the fluid B also acts on the inner wall of the cylinder and the inner end surface of the piston at the same time in an isobaric manner to push the piston to slide in the direction away from the piston and stretch and prolong the bag body, and the oblique spiral structure of the fibers of the reinforcing layer in the bag body can convert the axial tensile force into radial compression force to further compress the fluid A in the bag body to generate an additional increased pressure difference P_CI.e. P_A＝P_B+P_C＝P_B(1+ k), wherein k is always a positive value, the size of k is proportional to the area of the annular end surface on the inner side of the piston, and the k is positively correlated with the stretching elongation of the capsule. Under dynamic conditions, there are two reciprocal ways of pressure exchange between two fluids: in the first mode, when the fluid B is injected into the outer cavity of the capsule from the outside of the cylinder body through active pressure, the pressure of the fluid B acts on the outer wall of the capsule body and the annular inner side face of the piston at the same time, the piston is pushed to slide towards the side far away from the cylinder cover, the length of the capsule body is increased and the diameter of the capsule body is reduced and thinned due to the fact that the capsule body is simultaneously subjected to annular extrusion of the fluid B and the tensile force of the piston, the volume of the inner cavity of the capsule is. The process is a pressurization process of driving high-pressure small-suction-discharge fluid by low-pressure large-suction-discharge fluid. And in the second mode, when the fluid A is actively pressurized and injected into the bag inner cavity from the outside of the bag nozzle, the bag body is correspondingly expanded and deformed, namely the expanded and thickened length is shortened, the traction piston slides towards the side of the cylinder cover, the space of the bag outer cavity is compressed by the bag body and the piston together to reduce the volume, and the fluid B in the bag outer cavity is pressed and discharged out of the cylinder body. Therefore, the process is a pumping process with high pressure and small suction and discharge capacity driving low pressure and large suction and discharge capacity. In short, when the pressure-increasing bag is used in a forward direction, the large flow of the outer bag cavity drives the small flow of the inner bag cavity to increase the pressure; conversely, when used in reverse, the high pressure in the bladder lumen drives the low pressure in the bladder lumen to increase the flow rate, which is obviously consistent with the law of conservation of energy. In practical application, the device is connected with an external pipeline system, and the two processes can be cyclically and alternately operated continuously under the control of a corresponding switching valve.

Preferably, the cylinder cover can be installed at the end part of the cylinder barrel in a flange bolt mode or a thread screwing mode, and the sealing effect can be realized through sealing gaskets and precision machining matching.

Preferably, the locking sealing mode of embedding and connecting the sac nozzle in the cylinder cover or the piston mounting hole is any one or two of a stepped hole matching mode, a taper hole matching mode or an internal thread hole matching mode.

Preferably, according to the actual application requirement, the channel for the fluid A to enter and exit the inner cavity of the bag is arranged on one bag mouth in a cylinder cover or a piston mounting hole, and the special channels for injecting and outputting the fluid A can be respectively arranged on the bag mouths at two ends of the bag body.

Preferably, the outer bag cavity is provided with at least one passage for the fluid B to enter and exit on the cylinder barrel or the cylinder cover, and the injection port and the output port of the fluid B can be separately arranged on the cylinder barrel or the cylinder cover according to the actual application requirement.

Preferably, the mounting holes in the centers of the cylinder cover and the piston are provided with threads for mounting a valve member, a connecting piece or a sealing piece.

Preferably, in the two fluids subjected to pressure conversion, the driving medium with actively changed pressure is any one of water, pressure liquid or compressed gas, and the driven fluid is any one of gas state, liquid state, solid-liquid mixed slurry state or gas-liquid phase change state.

Furthermore, two ends of the cylinder barrel can be respectively provided with a cylinder cover, the piston is arranged between the cylinder barrel and the cylinder barrel to divide the interior of the cylinder barrel into a left cylinder chamber and a right cylinder chamber, and the two cylinder chambers are respectively provided with a port for the fluid B to enter and exit on the cylinder barrel. One hydraulic bag is respectively arranged between the left side and the right side of the piston and the two cylinder covers, so that the expansion structure of the double hydraulic bags is formed. The working principle is as follows: when the fluid B is pressurized and injected into the left sac outer cavity under the control of the external reversing valve, the piston is pressed to slide rightwards, the left sac body is elongated and thinned, and the contained fluid A is pressurized and discharged through the left end sac mouth. Meanwhile, the right bag body shortens and expands, the volume of the inner cavity of the right bag body is expanded, the fluid A flows in through the bag nozzle at the right cylinder cover, and the fluid B in the outer cavity of the right bag body flows back to the outside of the cylinder body. The left and right alternate circulation work is realized, the two side capsule bodies push-pull each other through the middle piston, and the two capsule bodies assist each other by extension and contraction, so that the double-acting continuous pressurization can be realized, the residual pressure energy can be fully utilized, and the power consumption is saved.

The invention discloses the following technical effects:

compared with the prior art, the isolated fluid pressure conversion device with the linkage of the hydraulic bag and the piston has at least one of the following advantages:

1. the hydraulic bag can reliably and strictly isolate two fluid media with large pressure difference, and can effectively avoid mixed pollution among different media;

2. the flexible linkage structure of the telescopic hydraulic bag and the single piston can obviously reduce energy consumption generated by friction and vibration and improve energy conversion efficiency;

3. the inner flexible and outer rigid layer sleeve structure ensures that the hydraulic bag and the cylinder body share the internal high-pressure load, can greatly reduce the bearing load of the cylinder body, and is beneficial to reducing the weight of equipment and the manufacturing cost;

4. the device has good universality and large pressure adaptation range, is suitable for various fluids such as water, oil, gas and the like, and can realize two functions of pressurization transmission and pumping flow amplification by using one set of device in a reciprocal way;

5. the device has the advantages of simple and compact structure, low manufacturing process difficulty, cost saving and convenience in assembly and maintenance.

The technical effects of the invention are described in the specification in addition to the above list, directly or indirectly.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the following drawings only describe a part of the embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 is a schematic structural view of a fluid pressure exchange device according to the present invention;

FIG. 2 is a schematic view of the connection of the bladder nozzle with the cylinder head and the piston in the fluid pressure exchange device according to the present invention;

FIGS. 3 and 4 are schematic views illustrating the operation principle and process of the supercharging transmission of the fluid pressure exchange device of the present invention;

fig. 5 and 6 are schematic diagrams of the working principle and process of compression and pumping of the fluid pressure exchange device of the invention;

FIG. 7 is a schematic diagram of a dual-bladder type structure and an application of the fluid pressure exchange device of the present invention.

The cylinder comprises a cylinder body 1, a cylinder barrel 11, a cylinder cover 12, a piston 2, a mounting hole 21, a blind sealing piece 23, a hydraulic bag 3, a bag body 31, a bag mouth 32, a bag mouth through hole 33, a bag inner cavity 4, a bag outer cavity 5, an injection one-way valve 71, an output one-way valve 72 and a reversing valve 8.

Detailed Description

The technical solutions in the embodiments of the present invention will be described more clearly and more specifically with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic structural view of an isolated fluid pressure conversion device with a hydraulic bag and a piston linked together according to the present invention, and as shown in fig. 1, the device includes a cylinder 1, a piston 2, and a hydraulic bag 3. The cylinder body 1 is a rigid shell and comprises a cylinder barrel 11 with a cylindrical cavity inside and a cylinder cover 12 arranged at the end part of the cylinder barrel, and a longitudinally through mounting hole is formed in the center of the cylinder cover 12; the piston 2 is a sealable sliding piston which is arranged in the cylinder barrel 11 and has a diameter matched with that of the cylinder barrel, and the center of the piston is also provided with an axially through mounting hole 21; the hydraulic bag 3 is composed of a flexible tubular bag body 31 and bag mouths 32 at two ends of the flexible tubular bag body, the bag body 31 is a pressure-bearing tensile tubular flexible bag, the inner layer and the outer layer of the bag body are high-elasticity synthetic rubber anti-seepage layers, the middle layer is a reinforcing layer formed by obliquely and crosswise winding and weaving thin steel wires or synthetic fiber bundles, and the diameter and the length of the reinforcing layer can be changed along with the pressure difference between the inside and the outside and the stress at the two ends and can be expanded, contracted and stretched within a certain range. The mouthpiece 32 is a metal member assembled to the end of the body 31 for sealing and locking the mouth and connected to other members, and has a through hole 33 at the center thereof. (the technical details of the hydraulic bladder can be more fully understood by referring to domestic patent document CN 110566533A, the indicated range of the "hydraulic bladder" in the claims and the specification of the invention includes the "tubular hydraulic bladder" in the document, but the invention is not to be understood as being limited to this.) the hydraulic bladder 3 is arranged between the cylinder cover 12 and the piston 2 in the cylinder 11, and the bladder mouths 32 at both ends are respectively embedded into the mounting holes 21 at the centers of the cylinder cover 23 and the piston 3 and are sealed and locked by nuts. The body 31 of the hydraulic bag separates the cylindrical space in the cylinder 11 into two pressure-bearing chambers, namely a bag inner chamber 4 and a bag outer chamber 5, and respectively contains two different fluids, namely fluid A and fluid B.

Fig. 2 illustrates that three kinds of embedded locking and sealing manners, namely step hole matching, taper hole matching or internal thread hole matching, can be selected when the hydraulic bag 3 is connected with a cylinder cover and a piston through the bag mouth 32.

First embodiment, fig. 3 and 4 describe a connection mode and an operation process when the fluid pressure conversion device provided by the invention is applied to oil-water pressurization transmission. As shown in fig. 3 and 4, the hydraulic station is used as an external pressure source device, an oil supply pipe and an oil return pipe of the hydraulic station are connected to a port 14 of the outer bag cavity 5 on the cylinder body through a hydraulic pipe via a reversing valve 8, and the alternation of oil transportation and oil return processes can be realized by switching the stations of the reversing valve 8; the low-pressure water pump is an external preceding stage device for supplementing water to the bag inner cavity 4, is usually a servo pressurization pipeline pump, and is connected to the bag inner cavity 4 through a low-pressure water pipe and an injection one-way valve 71 arranged in an installation hole on the outer side of the piston 2; the output check valve 72 is installed in the mounting hole on the outer side of the cylinder cover 12, and is used for preventing the output high-pressure water from flowing back into the bag body and is connected to the high-pressure water expansion machine through a high-pressure pipe. Each working cycle comprises two alternative processes of water replenishing and pressurization:

the water replenishing process is as shown in fig. 3, when the reversing valve 8 is switched to the oil return pipe conducting station, the oil supply pipe is cut off, the hydraulic station enters a standby state, the low-pressure water pump starts water supply, when the water pressure reaches the forward opening pressure of the injection one-way valve 71, water starts to be injected into the bag inner cavity 4 through the low-pressure hose, the water injection pressure acts on the bag inner wall to force the bag body 31 to radially expand and thicken, the axial length is contracted, the traction piston 2 slides towards the side close to the cylinder cover 12, and the bag outer cavity 5 is in the low-pressure oil return state directly communicated with the oil storage tank pipeline of the hydraulic station at the moment, so the combined action of expansion of the bag body 31 and compression of the piston 2 reduces the volume of the bag outer cavity 5, which is equivalent to that the. When the bag body is filled with water to be full and the internal and external water pressures reach the equilibrium state under low pressure, the injection one-way valve 71 is closed, the pressure of the water outlet of the low-pressure water pump can rise to the set upper limit water pressure, the system automatically enters the standby state of suspending water supply, and the system is switched to the pressurization process.

The pressurizing process is as shown in fig. 4, when the reversing valve 8 is switched to the oil supply pipe conducting station, the oil return pipe is cut off, the hydraulic station starts to inject hydraulic oil into the bag outer cavity 5, the hydraulic oil pressurizes the water filling the bag inner cavity 4 from the periphery of the bag body 31 through the bag wall, meanwhile, the piston 2 is pushed to slide in the direction away from the cylinder cover 12, the bag body 31 tends to be lengthened and thinned due to the huge tensile force of the piston 2, the volume of the bag inner cavity 4 is reduced, the internal water pressure is further increased, and the water injection passage is reversely blocked by the injection one-way valve 71, so that high-pressure water can only be output from the output one-way valve through the high-pressure pipe to drive. When the water in the bag inner cavity 4 is exhausted or the internal and external water pressure reaches the equilibrium state under high pressure, the oil pressure at the outlet of the hydraulic station can rise to the set upper limit oil pressure, the system automatically enters the standby state of suspending oil supply, and the system is switched to the water supply process. In the process, the station switching of the reversing valve can be automatically controlled by standby signals of the low-pressure water pump and the hydraulic station, and can also be manually controlled according to requirements.

The embodiment is an application mode that the medium-pressure fluid is used for driving and the other low-pressure fluid is increased to high pressure, for example, 31.5MPa pressure fluid provided by a hydraulic station can be used for pressurizing low-pressure water not higher than 1.6MPa to high-pressure water above 70MPa, so as to drive mechanical equipment for doing work by water pressure. One feature that is of particular concern is: even if the water pressure in the bag body is pressurized to be more than 70MPa or even higher, the bag body bears the internal and external pressure difference of about 40MPa, and the oil pressure directly acting on the inner wall of the cylinder body does not exceed 31.5MPa all the time, which means that the cylinder body of the pressurizing device can be designed and manufactured according to the industrial standard of the universal hydraulic cylinder without specially improving the pressure bearing grade, which obviously contributes to saving the cost for users.

In practical applications, the pressurized medium may be water, mixed slurry such as paint and coating, and the driven actuator may be a grouting machine, a spraying machine, etc. besides the high-pressure water expander.

Second embodiment, fig. 5 and 6 illustrate an assembly method and an operation process of gas compression pumping by using the fluid pressure conversion device provided by the invention. As shown in fig. 5 and 6, the hydraulic station is used as an external power device, an oil supply pipe and an oil return pipe of the hydraulic station are connected to an oil inlet and outlet common port of the bag inner cavity 4 on the cylinder cover through a reversing valve 8 by a hydraulic pipe, and a blind plug sealing member 23 is installed in an installation hole on the outer side of the piston 2; the outer bag chamber 5 is provided with two ports of injection and output on the cylinder tube, and is respectively provided with an injection check valve 71 and an output check valve 72, and is respectively connected to an external low-pressure air source and a high-pressure storage tank through pressure pipelines. Each working cycle comprises two alternate processes of inflation and extrusion:

the inflation process is as shown in fig. 5, when the reversing valve 8 is switched to the oil return pipe conduction station, the oil supply pipe is cut off, the hydraulic station enters a standby state, the pressure of the hydraulic oil in the bag inner cavity 4 is suddenly reduced due to the opening of the oil return passage, the expansion pressure of the air in the bag outer cavity 5 is pressed to be reduced from thickness due to internal decompression of the bag body, the pulling force on the piston is released, the piston is pushed to slide away from the cylinder cover 12 side by the air pressure, the volume of the bag outer cavity 5 is increased, when the internal air pressure is reduced to be lower than the external air source pressure, the external air pushes the injection one-way valve to fill the bag outer cavity 5, the air pressure continuously pushes the piston to stretch the bag body to be the longest and the thinnest, most of the hydraulic oil is accelerated to flow back to the hydraulic station oil tank.

The compression process is as shown in fig. 6, when the reversing valve 8 is switched to the oil supply pipe conducting station, the oil return pipe is cut off, the hydraulic station starts to inject hydraulic oil into the bag inner cavity 4, the oil pressure rises along with the increase of the oil quantity in the bag inner cavity 4, the oil pressure acts on the inner wall of the bag body to force the bag body 31 to radially expand and become thick, the axial length shrinks, the piston 2 is pulled to slide towards the cylinder cover 12 side by huge pulling force, the volume of the bag outer cavity 5 is reduced by dozens of times under the double action of the bag body expansion and the piston compression, the gas inside is compressed, the density is increased, the pressure rises, and the gas is conveyed to the high. In the process, the station switching of the reversing valve 8 and the starting and stopping of the hydraulic station can be controlled by adding a sensor to detect the signals of the farthest position and the nearest position of the piston.

The embodiment is an application mode of compressing and pumping a large-flow low-pressure fluid driven by a small-flow high-pressure fluid, for example, compressed natural gas, petroleum gas or carbon dioxide gas with the pressure of less than or equal to 0.6MPa is further compressed and pressurized to more than 8MPa by a pressure liquid with the pressure of 31.5MPa provided by a hydraulic station, so that the pressure exceeds the liquefaction critical pressure, and the liquefaction, refrigeration or canning storage and transportation are carried out.

In practical application, the driving fluid medium is not limited to hydraulic oil, and water or emulsion can be used according to actual requirements; the fluid to be conveyed by pressurization is not limited to gas, but can also be liquid or viscous-state material and the like.

Third embodiment, fig. 7 illustrates a double hydraulic bag expanding structure of a fluid pressure conversion device according to the present invention, as shown in fig. 7, two ends of a cylinder 11 are respectively provided with a cylinder cover 12, and a piston 2 is disposed therebetween to divide the interior of a cylinder 1 into left and right cylinder chambers, and the left and right cylinder chambers have respective ports 14 for fluid to enter and exit on the cylinder 1. The left side and the right side of the piston 2 and the two cylinder covers 12 are respectively provided with a hydraulic bag 3, the outlet of a bag mouth 32 of the left hydraulic bag and the outlet of the right hydraulic bag which are arranged on the piston are blocked, and the bag mouth 32 is provided with an injection and output shared port in the mounting hole of the cylinder cover 12.

Fig. 7 also describes a matching mode and working principle when the double-hydraulic-bag expanding structure is applied to oil-water pressurization transmission. As shown in fig. 7, an oil supply pipe and an oil return pipe of the hydraulic station pass through a two-position four-way reversing valve 8 and are respectively connected to a left port 14 and a right port 14 on a cylinder body 1 through two hydraulic pipes, and the switching of the reversing valve 8 between two stations can enable the outer sac chambers 5 in the left cylinder chamber and the right cylinder chamber to be synchronously and alternately switched between two processes of oil injection and oil return; the low-pressure water pump is also connected to the water expansion machine after being respectively connected in series with two one-

way valves

71 and 72 through two water supply pipes, and a high-pressure water pipe is respectively divided between the injection one-way valve 71 and the output one-way valve 72 on the left path and the right path and is respectively connected to the inlet and outlet ports of the bag inner cavity 4 on the left cylinder cover 11 and the right cylinder cover 11. The left water path and the right water path are divided into three sections by four check valves, a low-pressure water supply pipeline is arranged before the check valves 71 are injected, a high-pressure water conveying pipeline is arranged after the check valves 72 are output, and the high-pressure pipeline between the two valves is shared by water replenishing and water discharging of the bag inner cavity 4.

The device with the double-hydraulic-bag structure can synchronously and alternately switch the bag outer cavities 5 in the left cylinder chamber and the right cylinder chamber between the processes of oil injection and oil return through switching the reversing valve 8 between two stations, namely, the processes of pressurization and water supplement are opposite and simultaneous on the left side and the right side of the piston 2. In addition, the expansion and contraction of the left and right side bladders 31 of the piston 2 are synchronous and opposite in phase, a push-pull effect with the force application directions consistent all the time is formed by the left and right reciprocating sliding of the piston 2, and the residual pressure of water supplement and oil return can be fully utilized, so that the energy conversion efficiency is effectively improved.

Obviously, when the second and third embodiments are combined, those skilled in the art will naturally understand that the expandable device with a dual-bladder structure can also be used in the reverse direction, i.e. the fluid a in the left and right bladder inner chambers 4 is used as a high-pressure drive to continuously compress and pump the low-pressure fluid B in the bladder outer chamber, so that the detailed description of such embodiments is omitted.

In conclusion, the fluid pressure conversion device provided by the invention innovatively adopts a conversion mechanism of a sleeve layer layered pressure-bearing structure with a flexible inner part and a rigid outer part and a bladder plug linkage, can strictly isolate two media to avoid mixed pollution, can expand the pressure adaptation range, is beneficial to reducing energy consumption and cost, and is suitable for pressurization transmission of hydraulic and pneumatic machines and pumping and pressure regulation of fluid materials in a pressure pipeline system.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A fluid pressure conversion device characterized by comprising: the hydraulic cylinder comprises a cylinder body (1), a piston (2) and a hydraulic bag (3);

the cylinder body (1) is a rigid shell and comprises a cylinder barrel (11) and a cylinder cover (12), a cylindrical cavity is arranged in the cylinder barrel (11), the cylinder cover (12) is installed at the end part of the cylinder barrel (11), a longitudinally through installation hole is formed in the center of the cylinder cover (12), and at least one port (14) for fluid media to enter and exit is formed in the cylinder body (1);

the diameter of the piston (2) is matched with that of the cylinder barrel (11) and is installed in the cylinder barrel (11) in a sliding mode, and an axial installation hole (21) is formed in the center of the piston (2);

the hydraulic bag (3) comprises a bag body (31) and a bag mouth (32), the bag body (31) is a pressure-bearing tensile tubular soft bag, an anti-seepage layer and a reinforcing layer are arranged in the bag wall, and the diameter and the length of the bag can change along with the pressure difference between the inside and the outside and the axial stress at two ends, and can radially expand and axially contract within a certain range; the bag mouth (32) is a connecting piece arranged at the end part of the bag body (31) and is used for locking, sealing the bag mouth and assembling and connecting with other components;

the hydraulic bag (3) is arranged between a cylinder cover (12) and a piston (2) in the cylinder barrel (11), bag nozzles (32) at two ends of the hydraulic bag (3) are respectively embedded into mounting holes in the centers of the cylinder cover (12) and the piston (2) to form a tight and sealed connection; the capsule body (31) separates a cylindrical space between a piston (3) in the cylinder barrel (11) and a cylinder cover (12) into a capsule inner cavity (4) and a capsule outer cavity (5) which are used for containing a first fluid and a second fluid respectively;

when the pressure-variable valve is in work, the pressure or the volume of fluid in any one of the inner bag cavity (4) and the outer bag cavity (5) is actively changed, the two fluids interact with each other through the combined action of expansion, contraction and extension of the bag body (31) and sliding of the piston (2), so that the pressure or the volume of the fluid in the other cavity is correspondingly changed, the change amount of the fluid pressure in the inner bag cavity (4) is larger than the change amount of the fluid pressure in the outer bag cavity (5), and the change amount of the volume of the outer bag cavity (4) is larger than the change amount of the volume of the inner bag cavity (5).

2. The fluid pressure conversion device according to claim 1, wherein the cylinder head (12) is mounted at the end of the cylinder tube (11) in either one or both of a flange bolt manner and a screw-in manner, and the sealing manner is either one or both of a sealing gasket manner and a precision machining fit manner.

3. The fluid pressure conversion device according to claim 1, wherein the locking sealing manner of the insertion connection of the sac nozzle (32) in the mounting holes of the cylinder cover (12) and the piston (2) is any one or two of stepped hole matching, taper hole matching or internal thread hole matching.

4. A fluid pressure transducer arrangement according to claim 1, wherein the bladder chamber (4) is provided with a passage for the first fluid to and from at least one of the cylinder head (12) and the piston (2) via the bladder nozzle (32).

5. A fluid pressure transducer arrangement according to claim 1, wherein the cylinder (1) is provided with at least one port (14) for ingress and egress of a second fluid in the outer bladder chamber (5).

6. A fluid pressure transducer arrangement according to claim 1, characterized in that the mounting holes in the centre of the cylinder head (12) and the piston (2) are provided with threads for mounting valve members, connections or seals or the like.

7. The fluid pressure conversion device according to claim 1, wherein the driving medium for active pressure change in the two fluids for pressure conversion may be any one of water, pressurized liquid or compressed gas, and the driven fluid may be any one of gas, liquid, solid-liquid mixed slurry or gas-liquid phase change.