RU2683051C1 - Method of operating piston pump-compressor and device therefor - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to the field of pump and compressor engineering and can be used to create hybrid piston volumetric machines of mainly low and medium productivity, designed to compress and feed the consumer simultaneously or alternately liquids and gases. Method of a reciprocating pump-compressor operation consists in alternating suction, compression and supply of gas and liquid to the consumer and consists in the fact that the suction and injection of fluid is carried out by changing the gas pressure. Pump-compressor contains cylinder 1 with suction 2 and discharge 3 valves connected to suction 4 and discharge 5 cavities. Liquid valves are made in the form of packages of hydrodiodes 6 and 7 in the lower part of cylinder 1 and are connected to suction 8 and discharge 9 cavities. Piston 10 is placed in cylinder 1 with the formation of piston 12 and sub piston 13 cavities. Cavity 13 is connected to cavity 5 through gas valve 14.EFFECT: increase in the specific with respect to mass and dimensions of productivity and efficiency is achieved.2 cl, 4 dwg

Description

The invention relates to the field of pump and compressor engineering and can be used to create hybrid reciprocating volumetric machines with mainly small and medium capacity, designed to compress and supply to the consumer simultaneously or alternately liquids and gases.

A known design of a piston pump compressor comprising a cylinder, piston, valve. The working chambers are structurally located above and below the piston. The method of operation of this design is to alternately compress and supply gas to the consumer from the supra-piston cavity, compress the fluid in the sub-piston cavity and supply it to the consumer (see RF patent No. 118371, MKI F04B 19/06 of 20.07.2012).

Also known is the design of a piston pump-compressor, consisting of a cylinder, a piston and valves, in which the working chambers are also located above and below the piston. The method of operation consists in alternately sucking, compressing and supplying gas to the consumer from the supra-piston cavity, and sucking and compressing the liquid in the subpiston cavity and supplying it to the consumer, the compressed gas being supplied to the consumer through a self-acting discharge valve and gas injection line, and the liquid is supplied to the consumer through fluid injection line (see, for example, RF Patent No. 125635 for the utility model “Piston Pump-Compressor”, IPC F04B 19/06, filed September 24, 2012, published March 10, 2013).

A disadvantage of the known structures and their methods of operation is a narrow range of pumping capacity and compressor cavity, since due to the large inertia of the fluid, the piston speed cannot be increased, which affects the performance of the compressor cavity.

Another significant drawback is the inability to work with liquids under high pressure, because this pressure is located in the crankcase, which makes it extremely difficult to seal the drive crankshaft, as well as flat joints of the structure (for example, the joint between the cylinder and the crankcase). In addition, at high fluid pressure (above 5 MPa), the crankcase material (and this is usually casting) has great strength requirements, which complicates the casting technology, or its walls have to be made thick, which worsens an indicator such as the material consumption of the structure. It should also be noted relatively large gas leaks through the gap between the piston and the cylinder during compression-injection in the compressor cavity, because at this time, a suction process takes place in the pump cavity, separated by a gap from the compressor cavity, i.e. fluid pressure is low and cannot prevent gas leaks. At the same time, in the process of compression-injection of the liquid, when suction occurs in the compressor cavity, the liquid can penetrate through the gap between the piston and the cylinder in large quantities and contaminate the compressible gas, and even lead to water hammer.

The objective of the invention is to expand the functionality in the direction of increasing specific productivity, reducing the mass of the structure, increasing the efficiency of the compressor cavity, as well as reducing the cost of operating the cooling system.

This objective of the invention is achieved by the fact that in the known method of operation of the pump-compressor according to the invention, the absorption and injection of liquid occurs by changing the pressure in the compressor cavity.

To implement this method in a piston pump compressor containing a cylinder with a piston installed in it, compressor and pump cavities connected to gas suction lines through self-acting self-acting valves, and with gas injection lines through self-acting pressure valves, and with liquid suction and discharge lines through the corresponding hydrodiodes. The piston divides the compressor cavity into two parts, the pump and one of the compressor cavities are located under the piston, the piston drive can be located at the top or bottom. The compressor cavity in this design works according to the principle of operation of a double-acting compressor.

As a result of these structural changes, the pump-compressor can work with the rotational speed of the reciprocating compressor and, thus, reduce its dimensions and increase the specific productivity. Due to the lack of valves in the pump cavity, the problem of the inertia of the valves at high frequencies of the pump-compressor is solved. Direct contact of the liquid with the compressible gas allows efficient cooling of the pump-compressor.

The invention is illustrated by the example of a constructive version of the pump compressor, schematically shown in the drawings.

In FIG. 1 shows a structural diagram of a piston pump compressor. The piston is at top dead center (TDC) at the very beginning of the down stroke.

In FIG. 2 shows a diagram of a pump-compressor in the process of moving a piston from TDC to bottom dead center (BDC).

In FIG. 3 shows a diagram of the pump compressor when the piston reaches the BDC.

In FIG. 4 shows a diagram of a pump compressor when the piston moves from BDC to TDC.

The compressor pump (Fig. 1) contains a cylinder 1 with a suction 2 and a discharge 3 gas valves, respectively connected to the suction 4 and discharge 5 cavities. The suction and discharge liquid valves are made in the form of packages of hydrodiodes, respectively 6 and 7, are located in the lower part of the cylinder 1 and are connected respectively to the suction 8 and discharge 9 cavities. Their minimum hydraulic resistance is directed from the cavity 8 of the fluid intake towards the cavity 9 of the fluid injection.

The piston 10 with the rod 11 is connected to the drive mechanism (not shown in the drawings) and placed in the cylinder 1 with the formation of the over-piston 12 and under-piston cavity 13.

The under-piston cavity 13 is connected to the gas injection cavity 5 through an additional injection gas valve 14 located between the position of the piston bottom 10 at bottom dead center and the discharge gas valve 3 of the over-piston cavity 12, and is partially filled with liquid 15.

Suction and discharge gas valves 2 and 3 are located below the bottom of the piston 10 when it is in TDC.

The method of operation of the piston pump compressor is as follows (Fig. 1). When the piston 10 is in TDC, the gas and liquid 15 in the cavity 13 are under suction pressure, the gas valves (2, 3, 14) are closed, in the “locked” cavity 12 the gas is compressed to a certain pressure determined by the discharge pressure and the volume of the cavity 12 , a pressure that is higher than the gas injection pressure. In the cavity 9, the liquid is under the pressure of the liquid injection, in the cavity 8, the liquid is under the suction pressure of the liquid, in the cavity 5 the gas is under the pressure of the gas injection.

Under the influence of the pressure difference between the cavities 9 and 8, the fluid flows through the hydrodiodes 7 from the cavity 9 to the cavity 13, and from there through the hydrodiodes 6 to the cavity 8. Due to the fact that the hydrodiodes in this direction have a large hydraulic resistance, this fluid flow is very small , about half of it goes to replenish the amount of fluid 15 and increase its level in the cavity 13, and half expires in the cavity 8.

When the piston 10 moves downward (Fig. 2), the gas is compressed under the piston in the cavity 13, and the cavity 12 increases in volume and the pressure in it drops. When the piston 10 crosses the level of valve 2, the pressure in it drops to the suction pressure, after which, with a continued increase in the volume of the cavity 12, a vacuum is created in it (this moment is shown in Fig. 2), the suction gas valve 2 opens, and the gas begins to be sucked into cavity 12.

With increasing gas pressure in the cavity 13, the pressure of the liquid 15 also increases (both pressures are the same, since there is no separation element between the liquid and gas), as a result of which the liquid 15 is displaced simultaneously through hydrodiodes 6 and 7 in the cavities 8 and 9.

Due to the fact that in this case the resistance of the hydrodiodes 6 to the opposite flow is much greater than the hydrodiodes 7 to the associated flow, the fluid flow is mainly directed through the hydrodiodes 7 towards the cavity 9, i.e. towards liquid injection to the consumer.

When the gas injection pressure in the cavity 13 is reached, the valve 14 opens, and the compressed gas from the cavity 13 enters the cavity 5 and then to the consumer.

With further movement of the piston to the BDC (Fig. 3), the piston 10 crosses the valve 14, connecting it to the cavity 12, and since the pressure in it is equal to the suction pressure, the discharge valve 14 is closed.

The remainder of the compressed gas in the cavity 13 continues to displace the liquid 15 from the cavity 13.

When the piston 10 reaches the position of the BDC, all of the above processes end.

When the piston 10 moves from the BDC to the TDC (Fig. 4), at first there is a complete expansion of the remnants of the gas compressed in the cavity 13, and then, due to the continuing increase in the cavity 13, a vacuum appears in it, due to which, the liquid begins to be absorbed into the cavity 13 from the suction cavity 8 and from the injection cavity 9.

Due to the fact that the hydrodiodes 6 have a low resistance to the passing flow, and the hydrodiodes 7 have a high resistance to the opposite flow, the replenishment of the liquid 14 occurs mainly due to the flow through the hydrodiodes 6 from the suction cavity 8. At the same time, the liquid level 15 rises and 13 depression is supported.

At the same time, the volume of the cavity 12 decreases, the gas pressure in it increases, the valve 2 closes, and when the gas pressure is equal to the discharge pressure, the discharge valve 3 opens, and the gas enters the cavity 5 and from there to the consumer.

When the piston 10 approaches the TDC position, it opens access to gas from the suction cavity 4 to the cavity 13, in which the pressure is much lower than the suction pressure, as a result of which the valve 2 opens, and the gas fills the free space of the cavity 13.

Then the cycle of the pump-compressor is repeated.

Obviously, the total flow rate of the liquid 14 during the reciprocating movement of the piston 10 is directed towards the discharge cavity 9 and then to the consumer.

The absence of valves with movable massive elements on the suction-discharge lines of the liquid 15 allows you to bring the frequency of the reciprocating movement of the piston 10 to the frequency characteristic of piston compressors, which is about 2 times higher than the applied frequencies for piston pumps. This makes it possible to significantly reduce the size and weight of the pump compressor, i.e. increase its specific productivity.

The constant direct contact of the liquid 15 with the compressible gas makes it possible to substantially approximate the process of gas compression in the cavity 13 to the isothermal one, and thereby increase the efficiency of the machine without any costs for the cooling system.

Thus, the technical task of the invention is the expansion of functionality in the direction of increasing specific productivity, reducing the mass of the structure, increasing the efficiency of the gas compression-injection process, as well as reducing the cost of operating the cooling system, is fully implemented.

Claims (2)

1. The method of operation of a piston pump compressor, which consists in alternately sucking, compressing and supplying gas and liquid to the consumer, characterized in that the suction and discharge of the liquid is carried out by changing the gas pressure. 2. A piston pump-compressor for implementing the method according to claim 1, comprising a cylinder with suction and discharge gas and liquid valves connected to the respective suction and discharge cavities, a piston connected to the drive mechanism and placed in the cylinder with the formation of the over-piston and under-piston cavity, characterized in that the piston cavity is connected to the gas injection cavity through an additional discharge gas valve located between the position of the piston at bottom dead center and with a gas valve of the over-piston cavity, the suction and discharge gas valves are located below the piston bottom at its top dead center position, and the lower part of the piston cavity is connected to the suction and injection cavities of the fluid through hydrodiodes with the direction of minimal hydraulic resistance from the suction cavity to the side of the fluid injection cavity .

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