CN210623013U - Multi-cylinder piston type expansion-compressor - Google Patents

Multi-cylinder piston type expansion-compressor Download PDF

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CN210623013U
CN210623013U CN201920613184.7U CN201920613184U CN210623013U CN 210623013 U CN210623013 U CN 210623013U CN 201920613184 U CN201920613184 U CN 201920613184U CN 210623013 U CN210623013 U CN 210623013U
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cylinder
expansion
piston type
piston
air suction
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马一太
王派
李昱翰
李敏霞
詹浩淼
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Tianjin University
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Tianjin University
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Abstract

The utility model belongs to the technical field of refrigeration/heat pump, a multi-cylinder piston expansion-compressor is disclosed. The crankshaft in the multi-cylinder piston type expansion-compressor is connected with a plurality of piston type compression cylinders and at least one piston type expansion cylinder. The piston type expansion cylinder receives thrust generated by expansion of a high-pressure working medium and pushes a piston of the expansion cylinder; the expansion cylinder piston applies thrust on the crankshaft through a connecting rod; the crankshaft is under the combined action of the motive power and the thrust generated by the expansion of the high-pressure working medium, and the piston of the compression cylinder is pushed to reciprocate by the connecting rod, so thatThe piston type compression cylinder does work. The utility model discloses a multi-cylinder piston inflation-compressor utilizes the thrust that the high pressure working medium inflation in the operating system produced, and the effective replenishment as the motive power carries out the acting, has practiced thrift the energy of prime mover. The utility model discloses can make natural working medium CO2The expansion work generated in the refrigeration/heat pump system is directly and efficiently utilized in the compression process of the working medium, thereby improving the cycle efficiency of the system.

Description

Multi-cylinder piston type expansion-compressor
Technical Field
The utility model belongs to the technical field of refrigeration/heat pump, concretely relates to multi-cylinder piston expansion-compressor.
Background
In the development process of refrigeration technology, the updating and upgrading of refrigerants are always very important technological promotion means. Refrigerant development is also accompanied by ozone destruction and greenhouse effect problems. Environmental issues are especially acute at the fourth meeting in the montreal protocol in 1992 and at the 19 th meeting in the member country in the montreal protocol in 2007, and the call for the phase out of refrigerants with high GWP (global warming potential) and high ODP (ozone attenuation potential) is very high.
Refrigerants are also indispensable in other industrial production and daily life. These demands have led to the development of refrigerants. In recent years, fourth generation refrigerants typified by natural media and near-natural media have been rapidly developed.
The fourth generation refrigerant, such as near natural working fluids (HFOs type working fluids), has high synthesis and manufacturing costs. This means that the production process will bring high energy consumption and high emission, and the secondary greenhouse effect will come with it. And CO2As a natural working medium, the refrigerant has many advantages, such as environmental friendliness (ODP is 0, and GWP is 1), safety, no toxicity, nonflammability, good heat transfer performance, good fluidity, large volume refrigerating capacity, compatibility with common lubricants and structural materials, low price, low maintenance cost and the like. CO22Therefore, the refrigerant becomes a high-quality refrigerant working medium.
Due to CO2If applied to a refrigeration/heat pump cycle, the system can be circulated transcritically (the suction pressure of the compressor is lower than the critical pressure, and the discharge pressure is higher than the critical pressure). However, CO2There are also some technical barriers to heat pump systems, the most major problems being: because the pressure in the refrigerating system is high, the throttling loss is large。CO2The efficiency of the transcritical cycle is generally lower than that of the subcritical cycle of the common working medium (the suction pressure and the exhaust pressure of the compressor are both lower than the critical pressure). In order to reduce the throttling loss of the transcritical cycle, a device is needed to replace the throttling valve, so that the throttling efficiency of the system is improved.
The expander is a mechanical principle which utilizes the expansion process of compressed gas generated in the system to output mechanical work outwards so as to obtain energy, and has the effect of reducing the temperature and the pressure of the gas at the same time. Expanders have found widespread use in cryogenic devices. However, in the conventional research, the expander and the compressor are mostly designed separately, and the compressor cannot be operated by directly utilizing the mechanical expansion work output by the expander. Therefore, it is necessary to design a compression and expansion integrated device capable of directly recycling the mechanical work of expansion for CO2The working medium is fully utilized, and the expansion mechanical work output by the expansion machine is used as supplementary kinetic energy, so that the energy consumption of a prime motor is reduced, and the energy conservation and emission reduction are promoted.
Disclosure of Invention
The utility model aims at the above-mentioned problem that prior art exists, provide an expander and compressor integration's multi-cylinder piston inflation-compressor to realize the compressor with the direct recycle's of mechanical work of expansion function, with the energy saving.
The utility model adopts the following technical scheme:
a multi-cylinder piston type expansion-compressor comprises a crankshaft and a connecting rod connected with the crankshaft; the crankshaft is provided with a plurality of extending sections, and each extending section is connected with two connecting rods which are arranged in a V shape in a staggered manner; each connecting rod is respectively connected with air cylinders with the same geometric parameters through pistons with the same geometric parameters; one cylinder arranged at one end of the crankshaft is a piston type expansion cylinder, and the rest cylinders are piston type compression cylinders; the piston located in the piston type compression cylinder is a compression cylinder piston, and the piston located in the piston type expansion cylinder is an expansion cylinder piston; high-pressure working media in the piston type expansion cylinder expand to push the expansion cylinder piston to apply acting force on the crankshaft, and the acting force is transmitted to each compression cylinder piston through the connecting rod; the acting force and an external prime mover jointly provide power for the work of each piston type compression cylinder; when the total number of the cylinders is odd, 1 cylinder with the same geometric parameters is added as a spare cylinder at the extension section of the crankshaft with the lack of cylinders.
The extending directions of two adjacent extending sections on the crankshaft 1 are opposite, so that the stress of the crankshaft and each connecting rod is relatively balanced.
A compression cylinder exhaust structure is arranged on a cylinder cover of each piston type compression cylinder; an expansion cylinder exhaust structure is arranged on a cylinder cover of each piston type expansion cylinder; the compression cylinder exhaust structure and the expansion cylinder exhaust structure comprise an exhaust pipe, an exhaust cavity and an exhaust valve which are sequentially connected in series; each cylinder cover is also provided with a corresponding compression cylinder air suction structure and a corresponding expansion cylinder air suction structure; the compression cylinder air suction structure and the expansion cylinder air suction structure respectively comprise an air suction pipe, an air suction cavity and an air suction valve which are connected in series.
The air suction pipe inlet of each piston type compression cylinder is connected with the compression cylinder main air suction pipe connected with the outlet of the external evaporator in parallel; the outlet of the exhaust pipe of each piston type compression cylinder is connected in parallel with the main exhaust pipe of the compression cylinder connected with the inlet of an external gas cooler; the inlet of the air suction pipe of the piston type expansion cylinder is connected to the main air suction pipe of the expansion cylinder and is directly connected with the outlet of the external gas cooler/through a high-pressure throttle valve positioned outside, the outlet of the exhaust pipe of the piston type expansion cylinder is connected to the main exhaust pipe of the expansion cylinder, and is directly connected with the inlet of the external evaporator/through a low-pressure throttle valve positioned outside.
The outlet of the exhaust pipe of each piston type compression cylinder is connected with the air suction pipe of the adjacent piston type compression cylinder end to form a series structure of all the piston type compression cylinders; the front end of the air suction pipe of the piston type compression cylinder arranged at the first position is connected with a compression cylinder main air suction pipe connected with an outlet of an external evaporator; the exhaust pipe of the piston type compression cylinder arranged at the last position is connected with a compression cylinder main exhaust pipe connected with an external gas cooler inlet; the inlet of an air suction pipe of the piston type expansion cylinder is connected to a main air suction pipe of the expansion cylinder and is directly connected with the outlet of the external gas cooler/through a high-pressure throttle valve positioned outside, the outlet of the exhaust pipe of the piston type expansion cylinder is connected to a main exhaust pipe of the expansion cylinder, and the outlet of the exhaust pipe of the piston type expansion cylinder is directly connected with the inlet of the external evaporator/through a low-pressure throttle valve positioned outside.
The number of the piston type expansion cylinders is more than 2, and the piston type expansion cylinders are continuously arranged on the extending section at one end of the crankshaft; when the total number of the cylinders is odd, supplementing one spare cylinder; correspondingly, the number of extension of the crankshaft matches the total number of cylinders.
The air suction pipe inlet of each piston type compression cylinder is connected in parallel with a compression cylinder main air suction pipe positioned at the outlet of an evaporator positioned outside; the outlet of the exhaust pipe of each piston type compression cylinder is connected with a compression cylinder main exhaust pipe of an external gas cooler inlet in parallel; the air suction pipe inlet of each piston type expansion cylinder is connected with a main air suction pipe of the expansion cylinder in parallel and is directly/through a high-pressure throttle valve positioned outside to be connected with the outlet of the external gas cooler; the outlet of the exhaust pipe of each piston type expansion cylinder is connected with the main exhaust pipe of the expansion cylinder in parallel, and is directly/through an external low-pressure throttle valve connected with the inlet of an external evaporator.
The outlet of the exhaust pipe of at least 2 piston type compression cylinders is connected with the air suction pipe of the adjacent piston type compression cylinder end to form a partial piston type compression cylinder series structure; the front end of the air suction pipe of the piston type compression cylinder arranged at the first position in the partial piston type compression cylinder series structure is a partial compression cylinder main air suction pipe, and the rear end of the exhaust pipe of the piston type compression cylinder arranged at the last position in the partial piston type compression cylinder series structure is a partial compression cylinder main exhaust pipe; all the partial compression cylinder main air suction pipes are connected in parallel with the compression cylinder main air suction pipe and connected with an external evaporator outlet; outlets of all the local compression cylinder main exhaust pipes are connected in parallel with the compression cylinder main exhaust pipe and connected with an inlet of an external gas cooler; the air suction pipe inlet of each piston type expansion cylinder is connected with an expansion cylinder main air suction pipe in parallel and is connected with an external gas cooler outlet directly/through a high-pressure throttle valve positioned outside; and forming a parallel-series structure of the cylinder in which the piston type compression cylinder is combined in parallel with the piston type expansion cylinder.
The partial piston type compression cylinder series structure is a series structure of two piston type compression cylinders.
The working medium is selected from CO2Natural working medium is applied to transcritical refrigeration/heat pump circulation.
The utility model has the advantages that:
(1) the utility model discloses a multi-cylinder piston expansion-compressor can realize the high-efficient direct utilization to high pressure working medium work of expansion in refrigeration/heat pump system to more show the energy that reduces the compressor consumption.
(2) The utility model discloses a multi-cylinder piston inflation-compressor can integrate expander and compressor, compact structure, saving equipment space.
(3) The utility model discloses a multi-cylinder piston expansion-compressor can adopt same parameter with the expansion cylinder with the compression cylinder, easily reforms transform to adapt to different refrigeration/heat pump system demands, reduce cost.
(4) The utility model discloses a multi-cylinder piston inflation-compressor can make compression and expansion process realize synchronous, easily control system operation cycle through single bent axle.
Drawings
FIG. 1 is a front view of a piston type expansion-compressor structure having a plurality of compression cylinders and 1 expansion cylinder
FIG. 2 is a right-side view of the utility model of FIG. 1
FIG. 3 is a schematic structural view of a single piston type compression cylinder/piston type expansion cylinder of the present invention
FIG. 4 is a schematic view of the expansion process of the piston expansion cylinder during the operation of the piston expansion-compressor of the present invention
FIG. 5 is a schematic diagram of the connection of the whole machine in the parallel connection mode of the cylinders of 1 expansion cylinder
FIG. 6 is a schematic diagram of the connection of the whole machine of the cylinder series connection mode of 1 expansion cylinder
FIG. 7 is a front view of the piston type expansion-compressor structure with a plurality of compression cylinders and expansion cylinders
FIG. 8 is a schematic diagram of the connection of the whole machine of the cylinder series-parallel connection mode of the expansion cylinder of more than 1
FIG. 9 is a complete machine connection schematic diagram of the full parallel connection mode of the cylinders of more than 1 expansion cylinder
Wherein: 1-crankshaft 2A-piston type compression cylinder 2B-piston type expansion cylinder 3A-compression cylinder piston 3B-expansion cylinder piston 4-external prime mover 5A-compression cylinder total suction pipe 6-expansion cylinder total exhaust pipe 7-crankcase 8-connecting rod 9-compression cylinder total exhaust pipe 10A (10B) -exhaust pipe 11A (11B) -exhaust cavity 12A (12B) -exhaust valve 13A (13B) -intake valve 14A (14B) -intake cavity 15A (15B) -intake pipe 16A (16B) -cylinder head 17-gas cooler 18-evaporator 19-high pressure throttle valve 20-low pressure throttle valve 21-expansion cylinder total intake pipe a-intake process start stage B-expansion process start stage c-exhaust process start stage d-exhaust process intermediate stage
Detailed Description
The utility model relates to a multi-cylinder piston inflation-compressor, it can make full use of high-quality working medium (for example CO2 working medium), turns into supplementary kinetic energy with the expansion mechanical work of expander output to reduce the energy resource consumption to the prime mover, reach energy saving and emission reduction's purpose.
The following is a specific embodiment, and the technical scheme of the present invention is introduced as follows:
a multi-cylinder piston type expansion-compressor comprises a crankshaft 1 and a connecting rod 8 connected with the crankshaft 1; the crankshaft 1 is provided with a plurality of extending sections, and each extending section is connected with two connecting rods 8 which are arranged in a V shape in a staggered manner; each connecting rod 8 is respectively connected with air cylinders with the same geometric parameters through pistons with the same geometric parameters; one cylinder arranged at one end of the crankshaft 1 is a piston type expansion cylinder 2B, and the rest cylinders are piston type compression cylinders 2A; the piston in the piston type compression cylinder 2A is a compression cylinder piston 3A, and the piston in the piston type expansion cylinder 2B is an expansion cylinder piston 3B; high-pressure working media in the piston type expansion cylinder 2B expand to push the expansion cylinder piston 3B to apply acting force to the crankshaft 1 and transmit the acting force to each compression cylinder piston 3A through the connecting rod 8; the acting force and the external prime mover 4 jointly provide power for the work of each piston type compression cylinder 2A; when the total number of the cylinders is odd, 1 cylinder with the same geometric parameters is added as a spare cylinder at the extension section of the crankshaft 1 lacking the cylinders.
The extending directions of two adjacent extending sections on the crankshaft 1 are opposite, so that the stress of the crankshaft 1 and each connecting rod 8 is relatively balanced.
A cylinder head 16A of each piston type compression cylinder 2A is provided with a compression cylinder exhaust structure; an expansion cylinder exhaust structure is arranged on the cylinder cover 16B of each piston type expansion cylinder 2B; the compression cylinder exhaust structure and the expansion cylinder exhaust structure comprise an exhaust pipe 10A/10B, an exhaust cavity 11A/11B and an exhaust valve 12A/12B which are sequentially connected in series; each cylinder head 16A/16B is also provided with a corresponding compression cylinder air suction structure and a corresponding expansion cylinder air suction structure; the compression cylinder air suction structure and the expansion cylinder air suction structure respectively comprise an air suction pipe 15A/15B, an air suction cavity 14A/14B and an air suction valve 13A/13B which are connected in series.
The inlet of the air suction pipe 15A of each piston type compression cylinder 2A is connected in parallel with the compression cylinder main air suction pipe 5 connected with the outlet of an external evaporator 18; the outlet of the exhaust pipe 10A of each piston type compression cylinder 2A is connected in parallel with the compression cylinder main exhaust pipe 9 connected with the inlet of an external gas cooler 17; the inlet of the suction pipe 15B of the piston expansion cylinder 2B is connected to the expansion cylinder main suction pipe 21 and is connected directly to the outlet of the external gas cooler 17 via an external high-pressure throttle valve 19, the outlet of the exhaust pipe 10B of the piston expansion cylinder 2B is connected to the main expansion cylinder exhaust pipe 6 and is connected directly to the inlet of the external evaporator 18 via an external low-pressure throttle valve 20.
The outlet of the exhaust pipe 10A of each piston type compression cylinder 2A is connected with the air suction pipe 15A of the adjacent piston type compression cylinder 2A end to form a series structure of all the piston type compression cylinders 2A; the front end of a suction pipe 15A of a piston type compression cylinder 2A arranged at the first position is connected with a compression cylinder main suction pipe 5 connected with the outlet of an external evaporator 18; the exhaust pipe 10A of the piston type compression cylinder 2A arranged at the last position is connected with a compression cylinder main exhaust pipe 9 connected with the inlet of an external gas cooler 17; the inlet of the suction pipe 15B of the piston expansion cylinder 2B is connected to the expansion cylinder main suction pipe 21 and is connected directly to the outlet of the external gas cooler 17 via an external high-pressure throttle valve 19, the outlet of the exhaust pipe 10B of the piston expansion cylinder 2B is connected to the expansion cylinder main exhaust pipe 6 and is connected directly to the inlet of the external evaporator 18 via an external low-pressure throttle valve 20.
The number of the piston type expansion cylinders 2B is more than 2, and the piston type expansion cylinders are continuously arranged on the extending section at one end of the crankshaft 1; when the total number of the cylinders is odd, supplementing a standby cylinder; correspondingly, the number of protruding sections of the crankshaft 1 matches the total number of cylinders.
The inlet of the air suction pipe 15A of each piston type compression cylinder 2A is connected in parallel with the compression cylinder main air suction pipe 5 at the outlet of the evaporator 18 positioned at the outside; the outlet of the exhaust pipe 10A of each piston type compression cylinder 2A is connected in parallel with the compression cylinder main exhaust pipe 9 at the inlet of the external gas cooler 17; the inlet of the suction pipe 15B of each piston type expansion cylinder 2B is connected with the expansion cylinder main suction pipe 21 in parallel and is connected with the outlet of the external gas cooler 17 directly/through an external high-pressure throttle valve 19, the outlet of the exhaust pipe 10B of each piston type expansion cylinder 2B is connected with the expansion cylinder main exhaust pipe 6 in parallel and is connected with the inlet of the external evaporator 18 directly/through an external low-pressure throttle valve 20.
The outlets of the exhaust pipes 10A of at least 2 piston type compression cylinders 2A are connected with the air suction pipes 15A of the adjacent piston type compression cylinders 2A end to form a partial piston type compression cylinder series structure; the front end of an air suction pipe 15A of a piston type compression cylinder 2A arranged at the first position in the series structure of the local piston type compression cylinders is a main air suction pipe of the local compression cylinder, and the rear end of an air exhaust pipe 10A of a piston type compression cylinder 2A arranged at the last position in the series structure of the local piston type compression cylinders is a main air exhaust pipe of the local compression cylinder; all the partial compression cylinder main air suction pipes are connected in parallel with the compression cylinder main air suction pipe 5 and connected with the outlet of an external evaporator 18; the outlets of all the local compression cylinder main exhaust pipes are connected in parallel with the compression cylinder main exhaust pipe 9 and connected with the inlet of an external gas cooler 17; the inlet of the air suction pipe 15B of each piston type expansion cylinder 2B is connected with the expansion cylinder main air suction pipe 21 in parallel and is connected with the outlet of an external gas cooler 17 directly/through a high-pressure throttle valve 19 positioned at the outside, the outlet of the exhaust pipe 10B of each piston type expansion cylinder 2B is connected with the expansion cylinder main exhaust pipe 6 in parallel and is connected with the inlet of an external evaporator 18 directly/through an external low-pressure throttle valve 20; and a parallel-series structure of the cylinder is formed, wherein the piston type compression cylinder 2A is connected in parallel with the piston type expansion cylinder 2B in parallel.
The partial piston type compression cylinder series structure is a series structure of two piston type compression cylinders 2A.
Working medium selects CO2Natural working medium is applied to transcritical refrigeration/heat pump circulation.
The following describes the specific structure of the present invention in detail with reference to the accompanying drawings (the partial cross-sections in the drawings are all located on the plane formed by the rotation axis of the crankshaft 1 and the cylinder center line):
as shown in fig. 1-6, the embodiment is a 4-cylinder piston type expansion-compressor, which comprises 1 expansion cylinder and 3 compression cylinders.
In this embodiment, the crankshaft 1 disposed in a crankcase 7 includes two opposite directions (using 180 degrees along the center of the crankshaft 1)0) And two connecting rods 8 connected in a V-shape (angle α depends on the working condition), 3 of the 4 cylinders are piston type compression cylinders 2A, 1 cylinder is piston type expansion cylinder 2B, the piston type expansion cylinder 2B is connected with one end of the crankshaft, the external prime mover 4 selects an electric motor in the embodiment, the multi-cylinder piston type expansion-compressor is connected with a CO2In a refrigeration/heat pump system (in this embodiment, the working medium is CO2),
As shown in fig. 5, the 4-cylinder piston type expansion-compressor adopts a connection mode that 3 piston type compression cylinders 2A are connected in parallel. Specifically, the air suction pipes 15A corresponding to the piston type compression cylinders 2A are connected in parallel to the same total air suction pipe 5, and the exhaust pipes 10A corresponding to the piston type compression cylinders 2A are connected in parallel to the total exhaust pipe 9; the main suction pipe 5 is connected with the outlet of the evaporator 18 to obtain low-pressure gas after evaporation, and the outlet of the main exhaust pipe 9 is connected with the inlet of the gas cooler 17. An air suction pipe 15B of the piston type expansion cylinder 2B is connected with a high-pressure throttle valve 19 behind the air cooler 17, and high-pressure air which is primarily throttled to set pressure after being cooled is obtained; the exhaust pipe 10B is connected to the inlet of the evaporator 18 via a low pressure throttle valve 20, the low pressure throttle valve 20 being used to further reduce the working medium pressure after the expansion process.
After the low-pressure liquid working medium in the evaporator 18 is subjected to a heat exchange process and an evaporation process with the outside, the low-pressure liquid working medium absorbs heat and is evaporated into a low-pressure gas working medium, then the low-pressure gas working medium enters the total air suction pipe 5 and is divided into three parts, and the low-pressure gas working medium flows into each piston type compression cylinder 2A through the air suction pipe 15A, the air suction cavity 14A and the opened air suction valve 13A of each piston type compression cylinder 2A respectively. Then the suction valve 13A is closed, the crankshaft 1 drives the connecting rod 8 in the piston type compression cylinder 2A under the drive of the external prime motor 4 to push the compression cylinder piston 3A in each piston type compression cylinder 2A to compress the working medium from the evaporator 18, so that the pressure and the temperature of the working medium are raised to be high-pressure gas working medium, then the exhaust valve 12A is opened, the working medium is discharged through the exhaust cavity 11A and the exhaust pipe 10A, the exhaust valve 12A is closed, and the working medium is converged and flows into the main exhaust pipe 9.
After leaving the main exhaust pipe 9, the working medium enters a gas cooler 17 of the system, after releasing heat and reducing the temperature, flows into each piston type expansion cylinder 2B through an air suction pipe 15B, an air suction cavity 14B and an opened air suction valve 13B of the expansion cylinder 2B to carry out the expansion process. The working medium is expanded spontaneously in the piston type expansion cylinder 2B due to higher pressure; along with the expansion of the working medium, the temperature and the pressure of the working medium are reduced, and meanwhile, the expansion cylinder piston 3B is pushed to do work. Because the expansion cylinder piston 3B is connected with the crankshaft 1 through the connecting rod 8, the expansion work is used for assisting the driving of the crankshaft 1 and the movement of the piston 3A in each piston type compression cylinder 2A connected with the crankshaft, thereby realizing the direct utilization of the expansion work of the working medium, reducing the requirement of the whole system for providing power for the external prime motor 4, improving the total efficiency of the system and finally realizing the reduction of the energy consumption.
The working process of the piston expander can refer to fig. 4, and the specific process is as follows:
and (3) a gas suction process: and (B) starting an air suction process (a) and an expansion process (B), opening an air suction valve (13B), allowing a high-pressure gas working medium to enter the cylinder, and simultaneously pushing the piston (9B) to descend until the air suction valve (13) is closed.
And (3) an expansion process: the expansion process starts B-the exhaust process starts c, the piston 9B continues to be pushed down to bottom dead center, and the intake valve 13B and the exhaust valve 12B are both closed for the full stroke.
And (3) an exhaust process: exhaust event Start c-half exhaust event over d-intake event Start a, piston 9B returns from bottom dead center to top dead center under inertia and crankshaft 1 thrust, and exhaust valve 12B opens to release expanded CO2The working medium is discharged out of the expansion cylinder 3.
Then a new cycle of air suction-expansion-exhaust process is carried out again
After leaving the piston expansion cylinder 2B through the exhaust cavity 11B and the exhaust pipe 10B, the working medium is throttled and liquefied through the throttle valve 19, and enters the evaporator 18 again to absorb heat, evaporate and heat up to become a low-pressure gas working medium, thereby realizing complete compression-expansion refrigeration/heat pump circulation.
Alternatively, as shown in fig. 6, the parallel connection relationship between the piston type compression cylinders 2A may be changed to series connection, that is, the outlet of the evaporator 18 is connected to the suction pipe 15A of the first piston type compression cylinder 2A, the exhaust pipe 10A of the first piston type compression cylinder 2A is connected to the suction pipe 15A of the second piston type compression cylinder 2A, the exhaust pipe 10A of the second piston type compression cylinder 2A is connected to the suction pipe 15A of the third piston type compression cylinder 2A, and the exhaust pipe 10A of the third piston type compression cylinder 2A is connected to the inlet of the gas cooler 17, and the connection manner of the expansion cylinder 3 is not changed. The connection mode can realize multi-stage compression in the compression cylinder group to realize higher compression ratio, is suitable for the working condition with larger temperature difference, but can lead to the reduction of the flow of the compression working medium.
The utility model discloses still be applicable to the multi-cylinder piston expansion-compressor of the expansion cylinder more than 2, as shown in figure 7 ~ 9. The utility model can increase the number of the piston type compression cylinders 2A to four or more; correspondingly, the number of piston expansion cylinders 2B may be increased to 2 or more. At the moment, the number of the connecting rods 8 is increased according to the total number of cylinders, and the crankshafts 1 matched with the number of the extension sections are correspondingly selected according to the group number of the connecting rod groups with 1 group of 2 connecting rods 8; when the total number of cylinders is odd, a spare cylinder is provided at the extension of the crankshaft 1 of a single cylinder. If conditions permit, preferably an even number of expansion cylinders, connecting rods 8 of the expansion cylinders 2B are connected two by two to the same extension of the crankshaft 1.
Fig. 7 shows a schematic front view of a multi-cylinder piston type expansion-compressor with 2 expansion cylinders. The embodiment of the multi-expansion cylinder comprises 2 expansion cylinders 2B and 6 compression cylinders 2A, the crankshaft 1 is provided with 4 extending sections, and the extending directions of the continuous extending sections are opposite and are 180 DEG0
Fig. 8 is a schematic diagram showing a cylinder series-parallel connection relationship in which the compression cylinder gas paths are connected in parallel after being connected in series two by two and the expansion cylinder gas paths are connected in parallel, and fig. 9 is a schematic diagram showing a cylinder connection relationship in which the compression cylinder gas paths and the expansion cylinder gas paths are connected in parallel.
In the multi-cylinder piston type expansion-compressor cylinder series-parallel example shown in fig. 8, 2 expansion cylinders 2B are connected in parallel; every two compression cylinders 2A are connected with the exhaust pipe 10A of the other compression cylinder 2A through the air suction pipe 15A of one compression cylinder 2A to form a double-stage compression cylinder group, namely a partial piston type compression cylinder series structure, and 3 double-stage compression cylinder groups are formed in this way; the air suction pipe 15A at the head end of each two-stage compression cylinder group is a local compression cylinder main air suction pipe, is connected in parallel with the compression cylinder main air suction pipe 5 together, and is connected with the outlet of the evaporator 18; the exhaust pipe 10B at the tail end of each double-stage compression cylinder group is a local compression cylinder main exhaust pipe, is jointly connected with the compression cylinder main exhaust pipe 9 in parallel and is connected with an inlet of a gas cooler 17. Therefore, three groups of parallel two-stage compression can be realized simultaneously, the compression ratio is improved, and the compression amount of the working medium is increased. Correspondingly, each suction pipe 15B of 2 piston expansion cylinders 2B is connected in parallel to the outlet of the gas cooler 17, or to the outlet of the gas cooler 17 through a high pressure throttle valve 19; connecting each exhaust pipe 10B of the 2 piston-type expansion cylinders 2B to the evaporator 18 in a parallel manner, or to the evaporator 18 through a low-pressure throttle valve 20; therefore, the parallel expansion process can be realized, and the expansion amount of the working medium is increased. The parallel-series structure of the cylinder with the piston type compression cylinder 2A and the piston type expansion cylinder 2B combined in parallel can finally realize the multistage compression and expansion functions with larger capacity and meet the higher requirements of compression ratio and working medium flow.
In the example of the parallel connection of the multiple cylinder piston type expansion-compressor cylinders as shown in fig. 9, 2 expansion cylinders 2B are connected in parallel; all 6 suction pipes 15A of 6 compression cylinders 2A are connected to a compression cylinder main suction pipe 5, and 6 exhaust pipes 10A are connected to a compression cylinder main exhaust pipe 9, so that six-cylinder parallel single-stage compression is realized, and the compression amount of the working medium is greatly improved. Correspondingly, each suction pipe 15B of 2 piston expansion cylinders 2B is connected in parallel to the outlet of the gas cooler 17, or to the outlet of the gas cooler 17 through a high pressure throttle valve 19; connecting each exhaust pipe 10B of the 2 piston-type expansion cylinders 2B to the evaporator 18 in a parallel manner, or to the evaporator 18 through a low-pressure throttle valve 20; therefore, the parallel expansion process can be realized, and the expansion amount of the working medium is increased. The parallel connection structure of the air cylinders with the piston type compression cylinders 2A and the piston type expansion cylinders 2B combined in parallel can finally realize the single-stage compression and expansion processes with larger capacity and meet the higher requirement of working medium flow.
In a specific application, the high-pressure throttle 19 and the low-pressure throttle 20 may also be expansion valves.
The above description is of the preferred embodiments of the present invention, but the present invention is not limited to the above-described embodiments. The preferred embodiments described above are illustrative only and not limiting. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto and changes may be made without departing from the scope of the invention in its broader aspects. All of which fall within the scope of the present invention.

Claims (10)

1. A multi-cylinder piston type expansion-compressor comprises a crankshaft (1) and a connecting rod (8) connected with the crankshaft (1); the method is characterized in that: the crankshaft (1) is provided with a plurality of extending sections, and each extending section is connected with two connecting rods (8) which are arranged in a V shape in a staggered manner; each connecting rod (8) is respectively connected with air cylinders with the same geometric parameters through pistons with the same geometric parameters; wherein, one cylinder arranged at one end of the crankshaft (1) is a piston type expansion cylinder (2B), and the rest cylinders are piston type compression cylinders (2A); the piston located in the piston compression cylinder (2A) is a compression cylinder piston (3A), and the piston located in the piston expansion cylinder (2B) is an expansion cylinder piston (3B); high-pressure working media in the piston type expansion cylinder (2B) expand to push the expansion cylinder piston (3B) to apply acting force on the crankshaft (1), and the acting force is transmitted to each compression cylinder piston (3A) through the connecting rod (8); the acting force and an external prime mover (4) jointly provide power for the work of each piston type compression cylinder (2A); when the total number of the cylinders is odd, 1 cylinder with the same geometric parameters is added as a spare cylinder at the extension section of the crankshaft (1) which lacks cylinders.
2. Multi-cylinder piston expansion-compressor according to claim 1, characterized in that: the extending directions of two adjacent extending sections on the crankshaft (1) are opposite, so that the stress of the crankshaft (1) and each connecting rod (8) is relatively balanced.
3. Multi-cylinder piston expansion-compressor according to claim 1, characterized in that: a cylinder head (16A) of each piston type compression cylinder (2A) is provided with a compression cylinder exhaust structure; an expansion cylinder exhaust structure is arranged on a cylinder cover (16B) of each piston type expansion cylinder (2B); the compression cylinder exhaust structure and the expansion cylinder exhaust structure comprise exhaust pipes (10A/10B), exhaust cavities (11A/11B) and exhaust valves (12A/12B) which are sequentially connected in series; each cylinder head (16A/16B) is also provided with a corresponding compression cylinder air suction structure and a corresponding expansion cylinder air suction structure; the compression cylinder air suction structure and the expansion cylinder air suction structure respectively comprise an air suction pipe (15A/15B), an air suction cavity (14A/14B) and an air suction valve (13A/13B) which are connected in series.
4. A multi-cylinder piston expansion-compressor according to claim 3, characterized in that: the inlet of the air suction pipe (15A) of each piston type compression cylinder (2A) is connected with the total air suction pipe (5) of the compression cylinder connected with the outlet of an external evaporator (18) in parallel; the outlet of the exhaust pipe (10A) of each piston type compression cylinder (2A) is connected with the compression cylinder main exhaust pipe (9) connected with the inlet of an external gas cooler (17) in parallel; the inlet of an air suction pipe (15B) of the piston type expansion cylinder (2B) is connected to a main air suction pipe (21) of the expansion cylinder, the air suction pipe is directly connected with the outlet of an external gas cooler (17) through a high-pressure throttle valve (19) positioned outside, the outlet of an exhaust pipe (10B) of the piston type expansion cylinder (2B) is connected to a main exhaust pipe (6) of the expansion cylinder, and the outlet of the exhaust pipe is directly connected with the inlet of an external evaporator (18) through a low-pressure throttle valve (20) positioned outside.
5. A multi-cylinder piston expansion-compressor according to claim 3, characterized in that: the outlet of the exhaust pipe (10A) of each piston type compression cylinder (2A) is connected with the air suction pipe (15A) of the adjacent piston type compression cylinder (2A) end to form a series structure of all the piston type compression cylinders (2A); the front end of the air suction pipe (15A) of the piston type compression cylinder (2A) which is arranged at the first position is connected with a compression cylinder main air suction pipe (5) connected with the outlet of an evaporator (18) at the outside; the exhaust pipe (10A) of the piston type compression cylinder (2A) arranged at the last position is connected with a compression cylinder main exhaust pipe (9) connected with an inlet of an external gas cooler (17); the inlet of an air suction pipe (15B) of the piston type expansion cylinder (2B) is connected to a main air suction pipe (21) of the expansion cylinder, the air suction pipe is directly connected with the outlet of an external gas cooler (17) through a high-pressure throttle valve (19) positioned outside, the outlet of an exhaust pipe (10B) of the piston type expansion cylinder (2B) is connected to a main exhaust pipe (6) of the expansion cylinder, and the outlet of the exhaust pipe is directly connected with the inlet of an external evaporator (18) through a low-pressure throttle valve (20) positioned outside.
6. A multi-cylinder piston expansion-compressor according to claim 3, characterized in that: the number of the piston type expansion cylinders (2B) is more than 2, and the piston type expansion cylinders are continuously arranged on the extending section of one end of the crankshaft (1); when the total number of the cylinders is odd, supplementing one spare cylinder; correspondingly, the number of extension of the crankshaft (1) matches the total number of cylinders.
7. Multi-cylinder piston expansion-compressor according to claim 6, characterized in that: the inlet of the air suction pipe (15A) of each piston type compression cylinder (2A) is connected with a compression cylinder total air suction pipe (5) at the outlet of an evaporator (18) positioned outside in parallel; the outlet of the exhaust pipe (10A) of each piston type compression cylinder (2A) is connected with a compression cylinder main exhaust pipe (9) at the inlet of an external gas cooler (17) in parallel; the inlet of the air suction pipe (15B) of each piston type expansion cylinder (2B) is connected with a total air suction pipe (21) of the expansion cylinder in parallel and is directly connected with the outlet of an external gas cooler (17) through a high-pressure throttle valve (19) positioned at the outside, the outlet of the exhaust pipe (10B) of each piston type expansion cylinder (2B) is connected with a total exhaust pipe (6) of the expansion cylinder in parallel and is directly connected with the inlet of the external evaporator (18) through a low-pressure throttle valve (20) positioned at the outside.
8. Multi-cylinder piston expansion-compressor according to claim 6, characterized in that: the outlets of the exhaust pipes (10A) of at least 2 piston type compression cylinders (2A) are connected with the air suction pipes (15A) of the adjacent piston type compression cylinders (2A) end to form a partial piston type compression cylinder series structure; the front end of the air suction pipe (15A) of the piston type compression cylinder (2A) arranged at the first position in the partial piston type compression cylinder series structure is a partial compression cylinder total air suction pipe, and the rear end of the air exhaust pipe (10A) of the piston type compression cylinder (2A) arranged at the last position in the partial piston type compression cylinder series structure is a partial compression cylinder total air exhaust pipe; all the partial compression cylinder main air suction pipes are connected in parallel with a compression cylinder main air suction pipe (5) and connected with an outlet of an external evaporator (18); the outlets of all the local compression cylinder main exhaust pipes are connected in parallel with a compression cylinder main exhaust pipe (9) and connected with the inlet of an external gas cooler (17); the inlet of the air suction pipe (15B) of each piston type expansion cylinder (2B) is connected with a total air suction pipe (21) of the expansion cylinder in parallel and is directly connected with the outlet of an external gas cooler (17) through a high-pressure throttle valve (19) positioned at the outside, the outlet of the exhaust pipe (10B) of each piston type expansion cylinder (2B) is connected with a total exhaust pipe (6) of the expansion cylinder in parallel and is directly connected with the inlet of the external evaporator (18) through a low-pressure throttle valve (20) at the outside; and a parallel-series structure of the cylinder is formed, wherein the piston type compression cylinder (2A) is in parallel connection with the piston type expansion cylinder (2B).
9. Multi-cylinder piston expansion-compressor according to claim 8, characterized in that: the partial piston type compression cylinder series structure is a series structure of two piston type compression cylinders (2A).
10. A multi-cylinder piston type expansion-compressor according to any one of claims 1 to 9, wherein: the working medium is selected from CO2Natural working medium is applied to transcritical refrigeration/heat pump circulation.
CN201920613184.7U 2019-04-30 2019-04-30 Multi-cylinder piston type expansion-compressor Active CN210623013U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110005588A (en) * 2019-04-30 2019-07-12 天津大学 A kind of multi-cylinder piston expansion-compressor
TWI738478B (en) * 2020-08-26 2021-09-01 國立成功大學 Compressor for transcritical rankine cycle power generation system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110005588A (en) * 2019-04-30 2019-07-12 天津大学 A kind of multi-cylinder piston expansion-compressor
TWI738478B (en) * 2020-08-26 2021-09-01 國立成功大學 Compressor for transcritical rankine cycle power generation system

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