Free-piston compressor

Abstract

This utility model pertains to compressor engineering, specifically to a free-piston compressor with an electromagnetic drive. The technical result of the utility model is to increase the operating efficiency of a free-piston compressor. This technical result is achieved by the free-piston compressor's hollow piston, capable of accommodating a valve, and having a confuser section, a cylindrical section, and a diffuser section located downstream of the compressor flow. The diameter of the cylindrical section is smaller than the inlet diameter of the confuser, and the inlet diameter of the confuser is smaller than the outlet diameter of the diffuser. 5 clauses, 5 figs.

Description

[0001] Technical field

[0002] The utility model relates to the field of compressor engineering, namely to a free-piston compressor with an electromagnetic drive.

[0003] Technology Level

[0004] A free-piston compressor with an electromagnetic drive is a gas compression device in which a piston reciprocates within a cylindrical housing without the traditional crank mechanism. In this type of compressor, piston movement is achieved through electromagnetic interaction, simplifying the design and increasing efficiency.

[0005] The technology of interaction between an electromagnetic inductor and a magnetic piston (plunger) is also known for other devices for compressing a fluid, for example, an electromagnetic gas pump according to JP 2004232573 (priority date: 31.01.2003, owner Taisan Industrial Co Ltd), the plunger of which performs a sliding reciprocating motion inside a cylinder using intermittent magnetic attraction, in which the annular magnetic poles are located on the side of the return spring at both ends of the cylinder, and the annular magnetic circuit is on the side of the auxiliary spring, while the suction valve is built into the plunger design. Moreover, a groove is made on the outer end of the plunger at each edge, into which a fluororubber ring is inserted, the outer diameter of which is larger than the diameter of the plunger.The disadvantage of this solution is the use of a return spring for the compression stroke, the effectiveness of which decreases as the discharge pressure increases, and the dead volume created by the placement of the auxiliary spring significantly reduces the pressure-flow characteristics of the compressor.

[0006] A compressor based on a linear motor is known under patent RU 2792183 (priority date: December 22, 2022, copyright holder: Perm National Research Polytechnic University). It consists of a cylindrical housing, an inductor, a magnetic piston made of at least two ferromagnetic disks separated by a non-magnetic gasket, inlet and outlet valves, a ceramic insert with an anti-friction coating, and end walls. When voltage is applied to the inductor, a traveling magnetic field is generated along its inner surface, which acts on the magnetic piston. Reversing the current flow in the inductor windings alters the direction of the driving force for the magnetic piston.A disadvantage of this type of compressor is the presence of a ceramic insert between the ferromagnetic piston and the inductor windings, which impairs the interaction and control of the piston movement. This design will have increased leakage with increasing compression levels and high resistance to starting and piston movement when selecting the gap between the piston and the ceramic insert. In addition, during compressor operation, the heat from gas compression will cause thermal expansion of the piston, which can lead to its seizure and insufficient efficiency in general.

[0007] A compressor is known according to US Patent 4,965,864 (priority date December 7, 1987), consisting of a hollow closed cylinder, coils that generate magnetic flux and a ferromagnetic material separating these coils, a piston located within the cylinder, a means for powering the coils, a control logic circuit that controls the switching of the coils, means for determining the piston position connected to said control logic circuit, inlet and outlet ports in the cylinder body, and means for measuring temperature and pressure. The control system receives data from the piston position sensors and, based on embedded algorithms, applies voltage to selected inductor coils, creating a magnetic field that interacts with the magnetic piston in such a way as to produce the desired movement of the magnetic piston.

[0008] The closest in technical essence to the claimed one is a piston compressor with an electromagnetic linear drive according to patent RU 2784252 (priority date: 03.12.2009, copyright holders: Atlas Copco Airpower, Namlose Wennoutschap, Vrije Universiteit Brussels), comprising a housing with a compression chamber, inlet and outlet valves, a piston located with the possibility of reciprocating axial movement in the compression chamber between the top dead center and the bottom dead center by means of a drive limited by a kinematic mechanism to which said piston is connected, wherein said drive is formed exclusively by means of an electromagnetic linear drive of the piston. This solution is taken as a prototype.The disadvantage of this solution is the complex compressor design, which utilizes both an electromagnetic linear piston drive and a crank mechanism. The piston and one or more plungers connected to the piston are located within the cylinder. The piston is controlled by the crank mechanism, and the plunger is controlled by the electromagnetic drive. This design complicates compressor control and creates the potential for frequent mechanical and control failures. Inconsistencies between the crank and electromagnetic drives are also likely. The structural components they act on (the plunger and piston) are rigidly connected, making this solution ineffective. Furthermore, the crank mechanism limits the piston stroke length within the cylinder and increases the compressor's overall dimensions.

[0009] A common significant drawback of similar compressors with electromagnetic drive (in particular, free-piston ones) is the insufficient efficiency of the electromagnetic drive, which is structurally compensated by a crank mechanism, dampers, springs and blocks of rubber-like material on the edges of the cylinder.

[0010] The technical objective of this solution is to create a compressor design that uses a more efficient electromagnetic drive, in which the parameters of the piston magnets and the compressor housing inductor are reasonably dependent.

[0011] Essence Revealed

[0012] The technical result of the utility model is to increase the operating efficiency of a free-piston compressor. The technical result is achieved in that the free-piston compressor comprises a cylindrical housing with a magnetic piston, which is driven by groups of radially magnetized magnets located on the magnetic piston with the possibility of interacting with the running magnetic field of the inductor formed by the windings of the inductor located on the housing, and the piston is made hollow with the possibility of placing an inlet valve in it and has a confuser section, a cylindrical section and a diffuser section with a stud located along the flow direction, wherein the diameter of the cylindrical section is d ц is less than the diameter of the confuser inlet d1, and the diameter of the confuser inlet d1 is less than the diameter of the diffuser outlet d 2.

[0013] A free-piston compressor comprises a cylindrical housing with a magnetic piston located therein, configured to reciprocate in the axial direction, which is driven by groups of radially magnetized magnets placed on the magnetic piston with the ability to interact with the running magnetic field of the inductor formed by the windings of the inductor located on the housing, an inlet and outlet valve, and the piston is made hollow with the ability to accommodate an inlet valve in it and has a confuser section, a cylindrical section and a diffuser section located along the flow path, wherein the diameter of the cylindrical section d ц smaller than the diameter of the confuser inlet d1, and the diameter of the confuser inlet d1 is smaller than the diameter of the diffuser outlet d2, while a pin is located inside the piston, passing through the confuser section, the cylindrical section and the diffuser section and fixing the inlet valve in the piston.

[0014] The piston magnets are located on the cylindrical section of the piston. The confuser opening angle α1 is from 30° to 40°, and the diffuser opening angle α2 is from 8° to 12°.

[0015] Preferred piston section lengths:

[0016] confuser length equal to 1 to 1.5 diameters of the cylindrical section d ц ;

[0017] Length of cylindrical section equal to 4 to 5 diameters of the cylindrical section d ц ;

[0018] diffuser length equal to 3 to 4 diameters of the cylindrical section d ц .

[0019] Brief description of drawings

[0020] Fig. 1 - Free-piston compressor with electromagnetic drive;

[0021] Fig. 2 - Compressor piston, longitudinal section;

[0022] Fig. 3 - Compressor piston, cross-section;

[0023] Fig. 4 - Piston segment diameters.

[0024] Fig. 5 - Dimensional parameters of piston segments.

[0025] The figures shown are:

[0026] 1 - hollow cylindrical body,

[0027] 2 - inductor,

[0028] 3 - magnetic piston,

[0029] 4 - inlet valve,

[0030] 5 - exhaust valve,

[0031] 6 - inductor windings,

[0032] 7 - diffuser,

[0033] 8 - cylindrical section of the piston,

[0034] 9 - confuser,

[0035] 10 - hairpin;

[0036] 11 - permanent magnets;

[0037] d1- diameter of the confuser entrance;

[0038] d2- diffuser outlet diameter;

[0039] d ц - diameter of the cylindrical section;

[0040] - length of the confuser;

[0041] - diffuser length;

[0042] - length of the cylindrical section.

[0043] Implementation

[0044] A free-piston compressor with an electromagnetic drive is a piston compressor in which the motion is transmitted to the piston by an electromagnetic drive, without using a crank mechanism and / or mechanical action on the piston rod.

[0045] A free-piston compressor with an electromagnetic drive comprises a cylindrical body 1, on the outer surface of which an inductor 2 is placed, and in the inner cavity of the cylindrical body a magnetic piston 3 is placed, configured to reciprocate in the axial direction inside the body 1.

[0046] Inductor 2 is formed by ring-shaped electromagnetic windings of inductor 6 on the housing, wherein the windings of inductor 6 are located at an axial distance from each other.

[0047] The magnetic piston 3 is a sleeve with a through channel of a special shape, which can be divided into three sections located along the flow direction: a confuser 9, a cylindrical section of the piston 8 and a diffuser 7 (Fig. 2). The magnetic piston 3 is made hollow with the possibility of placing a check valve 4 in it. In the presented embodiment, the inlet valve 4 is located in the body of the piston 3, and the outlet valve 5 is on the housing of the compressor 1, it is also known to place valves 4 and 5 on one common or opposite sides of the housing of the compressor 1. To fix the valve 4 in the piston, there is a stud 10 passing through the confuser section, the cylindrical section and the diffuser section, its function is to support the central axis of the piston and fix the position of the valve 4 for efficient operation. Permanent magnets 11, combined into groups, are located on the periphery of the piston. In the preferred embodiment, the magnets are located only on the cylindrical section of the piston, sinceIn the proposed embodiment, its diameter is smaller than the sections of the diffuser 7 and confuser 9, which allows magnets 11 to be placed on the outer periphery without interfering with the reciprocating movements of the piston 3 and increasing the overall efficiency.

[0048] The special shape of the magnetic piston is the result of experiments confirming that the three-section design of piston 3 ensures optimal gas flow parameter distribution: acceleration at the inlet of confuser 9 for improved filling, stable compression in cylindrical section 8, and effective deceleration and pressure increase in diffuser 7 for improved compressed gas removal. This increases overall compressor efficiency, reduces mechanical stress, and improves thermal performance.

[0049] Confuser 9 - a section of tapering diameter from d1 - the diameter of the confuser entrance to d ц, where the inlet section is the widest, its task is to accelerate the movement of the gas medium in front of the main cylindrical section 8. By reducing the diameter, the flow velocity increases, which helps to reduce the pressure at the inlet to the cylindrical section, this reduces the resistance to piston movement and increases the efficiency of gas suction.

[0050] The cylindrical section of the piston 8 ensures tightness and the creation of the necessary compression pressure in the cylinder, its diameter over the entire surface is d ц The diameter of the cylindrical section determines the volume of the working chamber and the degree of gas compression. The piston design also includes magnets 11 located on the outer periphery of the cylindrical section.

[0051] Diffuser 7 slows the gas flow from the cylindrical section, increasing the outlet pressure. This helps reduce eddy losses and turbulence, improving the operation of exhaust valve 5 and the efficiency of compressed gas removal from the cylinder.

[0052] It has been determined that an increase in the overall efficiency of the compressor is achieved with the ratio of parameters

[0053] d ц <d1<d2,

[0054] where d1 is the diameter of the confuser entrance;

[0055] d2- diffuser outlet diameter;

[0056] d ц - diameter of the cylindrical section,

[0057] i.e. the diameter of the cylindrical section is smaller than the diameter of the confuser inlet, and the diameter of the confuser inlet is smaller than the diameter of the diffuser outlet.

[0058] At low speeds of the pumped gas (υ≈ 4 m / s), a decrease in pressure and an increase in flow velocity will occur at the confuser and cylindrical section, and a decrease in velocity and an increase in pressure will occur at the diffuser, as a result of which the pressure drop and gas flow through the valve will increase (Venturi effect).

[0059] To achieve optimal increase in compressor efficiency from the use of the Venturi effect, which provides a pressure drop and gas velocity between the wide sections of the piston (diffuser and confuser) and the narrow cylindrical section of the piston, the ratio of the lengths and diameters of these sections is preferable, where the length of the cylindrical section and the length of the diffuser much larger than the diameter of the cylindrical section d ц , and the length of the confuser slightly larger than the diameter of the cylindrical section d ц , preferably when the confuser opening angle α1 is from 30° to 40°, and the diffuser opening angle α2 is from 8° to 12°. For convenience, the diameter of the cylindrical section of the piston d is taken as the calculated value ц . With the above ratio of diameters d ц<d1<d2, длин участков поршня и углов раскрытия достигается соотношение параметров компрессора, которое приводит к более эффективному более эффективному перекачиванию газа через поршень. В наиболее предпочтительном варианте реализации длина конфузора equal to 1 to 1.5 diameters of the cylindrical section d ц

[0060]

[0061] Length of cylindrical section equal to 4 to 5 diameters of the cylindrical section d ц

[0062]

[0063] diffuser length equal to 3 to 4 diameters of the cylindrical section d ц

[0064]

[0065] These values ​​are considered preferable, since deviations from the specified parameters lead to deviations in achieving the technical effect, namely:

[0066] At the confuser, when the opening angle decreases (less than 30°), the effect of the gas velocity difference between the piston sections decreases, and when the opening angle increases above 40°, the resistance of the section increases, which negatively affects the piston characteristics. As the confuser length increases more than 1.5⋅d ц friction losses increase, and with a confuser length less than d ц resistance increases due to the flow being separated from the walls at the cylinder inlet.

[0067] On a diffuser, with a decrease in the opening angle (less than 8°), the resulting technical effect is insignificant and falls within the range of measurement instrument errors, while with an increase in the opening angle (more than 12°), the resistance of the section increases due to flow separation from the walls. With an increase in the diffuser length more than 4⋅d цThere is a loss of efficiency, since the difference in volume between the cylindrical section and the diffuser is insignificant, and as the length decreases, the piston resistance during movement increases.

[0068] The operating principle of a free-piston compressor with an electromagnetic drive is based on the interaction of the magnetic field of permanent magnets 8 and the running magnetic field of inductor 2. Magnetic piston 3, located in cylindrical body 1, is set in motion by groups of annular radially magnetized magnets 8 located on its body (a group of annular magnets means a group of magnets that is located on one circle around the piston body and forms a ring from a set of magnets; radially magnetized magnets mean magnets whose poles are located radially, magnetic lines between which go from the center of the circle on which the magnets are located to its periphery) when interacting with the windings of inductor 6 around the axial guide on body 1.

[0069] The utility model works as follows.

[0070] When voltage is applied to the windings of inductor 6, a running magnetic field is generated along the inner surface of inductor 2. This field interacts with magnetic piston 3 inside housing 1. The currents induced in the body of inductor 2 create a driving force that ensures reciprocating movement in the axial direction of magnetic piston 3 in cylindrical housing 1.

[0071] At low speeds of the pumped gas (υ≈4 m / s), the flow will obey Bernoulli's law, that is, as the gas flow speed increases, the pressure in it will drop and vice versa, as the flow speed decreases, the pressure in it will increase.

[0072] The working medium (preferably gas) at the confuser 9 and the cylindrical section 8 of the magnetic piston 3 accelerates and loses pressure, and at the diffuser section 7 the flow rate drops and its pressure increases, due to which the pressure difference at the inlet valve 4 increases, the gas flow through this valve increases and, as a result, the productivity and efficiency of the compressor increases.

[0073] When piston 3 moves in the forward direction (discharge stroke), compression and gas flow through outlet valve 5 occur. When piston 3 moves in the reverse direction (suction stroke), the pumped gas is sucked into the compressor working chamber (the space between the inlet valve 4 and outlet valve 5) through inlet valve 4. When piston 3 reaches one of its extreme positions, the control station (not shown) reverses the current flow in the windings of inductor 2. This change in current direction reverses the direction of the running magnetic field, causing piston 3 to begin moving in the opposite direction.

[0074] Thus, a free-piston compressor with an electromagnetic drive, the piston of which is made hollow with the possibility of placing a valve in it and has a confuser section, a cylindrical section and a diffuser section with a stud located along the flow direction, wherein the diameter of the cylindrical section is smaller than the diameter of the confuser inlet, and the diameter of the confuser inlet is smaller than the diameter of the diffuser outlet, increases the overall efficiency of the compressor.

Claims

1. A free-piston compressor comprising a cylindrical housing with a magnetic piston located therein, capable of reciprocating movement in the axial direction, which is driven by groups of radially magnetized magnets placed on the magnetic piston with the ability to interact with the running magnetic field of an inductor formed by the windings of the inductor located on the housing, an inlet and outlet valve, characterized in that the piston is made hollow with the ability to accommodate an inlet valve in it and has a confuser section, a cylindrical section and a diffuser section located along the flow path, wherein the diameter of the cylindrical section is d ц smaller than the diameter of the confuser inlet d1, and the diameter of the confuser inlet d1 is smaller than the diameter of the diffuser outlet d2, while a pin is located inside the piston, passing through the confuser section, the cylindrical section and the diffuser section and fixing the inlet valve in the piston.

2. A free-piston compressor according to paragraph 1, characterized in that the magnets are located only on the cylindrical section of the piston.

3. A free-piston compressor according to claim 1, characterized in that the opening angle of the confuser a1 is from 30° to 40°, and the opening angle of the diffuser a2 is from 8° to 12°.

4. A free-piston compressor according to paragraph 1, characterized in that the length of the confuser equal to 1 to 1.5 diameters of the cylindrical section d ц .

5. A free-piston compressor according to paragraph 1, characterized in that the length of the cylindrical section equal to 4 to 5 diameters of the cylindrical section d ц .

6. A free-piston compressor according to paragraph 1, characterized in that the length of the diffuser equal to 3 to 4 diameters of the cylindrical section d ц .

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