RU2801766C1 - Method of operation of reciprocating compressor with regenerative cooling and device for its implementation - Google Patents

Abstract

FIELD: compressor equipment.

SUBSTANCE: method of operation of a reciprocating compressor with regenerative cooling consists in alternately compressing and forcing a liquid and gaseous medium into the working chamber of cylinder 1. Cylinder 1 is alternately connected to sources of liquid and gaseous media. Sleeve 11 of cylinder 1 is made of a porous material. The bottom of piston 2, facing the compression and injection chambers, is covered with a porous material. In the course of compression and injection of liquid, part of it is placed in the porous materials of sleeve 11 and the bottom of piston 2.

EFFECT: improved cooling of parts of the cylinder-piston group and efficiency.

9 cl, 12 dwg

Description

The invention relates to the field of positive displacement machines and, in particular, to reciprocating compressors that operate in difficult climatic conditions, and to compressors that are subject to high demands for efficiency when compressing gases with a high pressure ratio in one stage.

Known methods of operation of a reciprocating compressor with regenerative cooling, which consist in alternately compressing and forcing a cylinder of a liquid and gaseous medium in its working chamber by alternately connecting the cylinder to a source of liquid and gaseous medium (see, for example, USSR author's certificate No. 1079882 "Gas distribution device of a piston compressor ", published on 03/15/84, USSR author's certificate No. 1019104 "Piston machine", published on 05/23/83, RF patent No. 2658715 "Method of operation of a piston hybrid power machine and a device for its implementation, publ. 06/22/2008, RF patent 2763099 "Method of operation of the liquid cooling system of a volumetric machine and a device for its implementation, publ. 12/27/2021).

Also known is the design of a reciprocating compressor containing a cylinder with a sleeve made of porous material with a piston placed in it, connected to a reciprocating movement mechanism and forming a compression chamber with the cylinder and a valve cover, and coolant is supplied to the sleeve made of porous material (see China patent). for utility model CN 216342676 U (45) "Compressors and compression cycle systems", 2022)

The disadvantage of this method and the designs that implement it is the low cooling efficiency of the cylinder-piston group heated when working with gas and cooled when working with coolant. This is due to the fact that the cooling of the walls of the compression chamber occurs only due to the thermal conductivity of the materials from which the walls of the compression chamber are made, as a result of which the temperature of the walls decreases very slowly, and the compressor is forced to pump a large amount of liquid, spending significant work on its compression. and moving.

The technical objective of the invention is to increase the cooling efficiency of the parts of the cylinder-piston group when pumping coolant through it, and thereby reduce the specific energy consumption and increase the efficiency of the compressor.

This problem is solved by the fact that in the method of operation of a reciprocating compressor with regenerative cooling, which consists in alternately compressing and forcing a cylinder of a liquid and gaseous medium in its working chamber by alternately connecting the cylinder to a source of liquid and gaseous medium, according to the invention, a part of the liquid is placed on the course of compression of the liquid in the material of the machine is a compression chamber, and the bottom of the piston facing the compression and discharge chamber is covered with a porous material.

At the same time, in a reciprocating compressor with regenerative cooling, containing a cylinder with a sleeve made of porous material with a piston placed in it, connected to the reciprocating motion mechanism and forming a compression chamber with the cylinder and the valve cover, which, through the distributor, alternately connecting this chamber through the return self-acting valves located in the valve cover of the cylinder, with a source of gas and liquid, according to the invention, the bottom of the piston, facing the compression chamber, is covered with a porous material.

Porous adsorbents, such as silica gels or zeolites, can be used as the porous material.

The porous material of the sleeve can be made in the form of a package of discs compressed along the axis of the cylinder with rough end surfaces that form capillaries upon contact.

The porous material of the sleeve can be made in the form of a compression spring, the coils of which have the shape of a rectangle, and on the surface of the rectangle, perpendicular to the axis of the spring, roughness is applied, and this spring, in the state installed in the cylinder, is compressed in the axial direction until the aforementioned rough surfaces come into contact, upon contact of which capillaries are formed.

On the bottom of the piston, concentric rings pressed on each other can be fixedly mounted, the inner and outer cylindrical surfaces of which have roughness that form capillaries upon contact, or a disc of porous material can be installed, which can be formed from a wire tangle or from compression springs by pressing them into disk shape.

The essence of the invention is illustrated by drawings.

Fig. 1 shows a general diagram of a reciprocating compressor with regenerative cooling in the process of working with gas, and Fig. 2 - with liquid.

In FIG. 3 shows a diagram of a cylinder in which the porous material of the sleeve is made in the form of a package of disks compressed along the axis of the cylinder with rough end surfaces that form capillaries upon contact, and in Fig. 4 shows such a disk.

In FIG. 5 shows a diagram of a cylinder in which the porous material of the sleeve is made in the form of a compression spring, the coils of which have the shape of a rectangle, and in Fig. 6 - the same view, in which the coils of the spring open during the compression of the liquid.

In FIG. 7 shows a diagram of a piston whose bottom, facing the compression chamber, is covered with a porous material in the form of concentric rings pressed on each other, the inner and outer cylindrical surfaces of which are made rough, and the roughness forms capillaries upon contact, and Fig. 8 shows such a ring.

In FIG. 9 shows a piston on the bottom of which a disk of porous material is mounted, and the disk itself is shown in FIG. 10.

In FIG. 11 and 12 show the process of forming a porous material disc, which is formed by pressing compression springs into a disc shape.

A reciprocating compressor with regenerative cooling (Figs 1 and 2) contains a cylinder 1 with a piston 2 placed in it, connected to a reciprocating motion mechanism 3 and forming a compression chamber 5 with the cylinder 1 and the valve cover 4, which, through the distributor 6, alternately connecting this chamber through self-acting check valves 7 (suction) and 8 (discharge) placed in the valve cover 4 of the cylinder 1, is connected to a source of gas and liquid 9 in the tank 10.

The cylinder 1 contains a sleeve 11 made of a porous material, for example, porous duralumin. Porous adsorbents, such as silica gels or zeolites, can be used as the porous material.

The distribution mechanism 6 contains a rod 12, which is simultaneously the armature of the electromagnet 13 with the winding 14 connected to the power source 15 through a thermal relay 16. The rod 12 has recesses 17 and 18, which serve to connect holes 19 and 20 with channels 21, 22, 23 and 24 , serving for suction and injection of gas and liquid. An adjustable throttle 25 and a heat exchanger 26 are installed on channel 24.

Rod 12 is pressed by spring 27 to the right and is fixed in two positions by retainer 28 using grooves 29 and 30.

The bottom of the piston facing the compression chamber 5 is covered with a porous material in the form of a disc 31.

In FIG. Figure 3 shows a fragment of a cylinder-piston pair, in which the porous material of the sleeve 11 is made in the form of a package of disks 40 compressed along the axis of the cylinder 1 with rough end surfaces 41, which form capillaries upon contact with each other (Fig. 4).

Roughnesses can be applied on one end, or on both in various ways: blade processing (cutting the ends with a cutter with a triangular profile of the cutting part), milling along the plane with a face mill; grinding; pressure methods (running in and vibration running in); sandblasting; laser processing, etc.

When a rough surface comes into contact with a smooth or rough surface, capillaries are formed in the contact zone, similar to the capillaries of a porous material.

In FIG. 5 shows a fragment of the construction, in which the porous material of the sleeve 11 is made in the form of a compression spring 50, the coils of which are in the form of a rectangle, and on the surface of the rectangle, perpendicular to the axis of the spring, roughness is applied. The spring 50, when installed in the cylinder 1, is compressed in the axial direction until the aforementioned rough surfaces come into contact. In this case, capillaries are formed in the contact zone of these surfaces, as in the case of rough discs 40.

The compression of the spring 50 until its coils touch is carried out by long elastic threaded ties 51, and the tightness of the compression chamber 5 in this embodiment is ensured by the seal 52, which allows the valve cover 4 to move in the axial direction without loss of tightness. The threaded connection 53 provides the installation of the cylinder 1 on the crankcase 54. The relay 16 is not conventionally shown in this drawing.

In FIG. 6 shows the same design at the moment when the liquid is compressed in the working chamber 5 to a pressure significantly higher than the pressure of the injected gas. In this case, the elastic ties 51 under the action of the force of this pressure are elongated so that a gap Δ appears between the upper end of the cylinder 1 and the valve cover 4, and a gap δ appears between the coils of the spring 50.

So, for example, if the ties 51 are extended by 0.2 mm, and the spring 50 contains 50 turns, then a distance of 0.004 mm, or 4 microns, will appear between the plane of the turns, in addition to the average gap formed when the rough surfaces of the spring turns come into contact.

The amount by which the valve cover 4 rises is regulated by changing the hydraulic resistance of the throttle 25 - the higher its resistance, the higher the pressure in the chamber 5 in the process of fluid compression, the greater the force acting on the cover 4, and the greater the amount it rises with a given elasticity ( stiffness) of screeds 51.

In FIG. 7 shows the piston 2, with the bottom facing the compression chamber 5, covered with a porous material, which in this example is formed by concentric rings 72 fixedly mounted on the ledge 71, pressed onto each other, the inner 73 and outer 74 cylindrical surfaces of which are rough (see Fig. also Fig. 8). When the rings are pressed, capillaries are formed between their rough cylindrical surfaces 73 and 74.

In FIG. 9 shows a section of piston 2, in which a disk 92 made of porous material is fixedly mounted on the bottom in the recess 91 (see also Fig. 10), which is fixed on the piston by a cover 94 perforated with holes 93 and a screw 95.

As a porous material, porous duralumin, porous bronze, commercially available balls with a diameter of 1.5 to 8 mm and granules with a particle size of 0.3 to 1.5 mm of activated alumina, brass mesh packages (minimum mesh size 0, 04 mm, GOST 6613-86), etc.

The disc can also be formed by pressing thin elastic tangled wire in the form of a disc, as well as by pressing sections of cylindrical coiled springs. The pressing process is shown in Fig. 11 and 12.

In FIG. 11 shows a mold 101 in which lengths of coiled coil springs 102 are loaded without any prior orientation. The rod 103 is needed to obtain a central fixing hole in the finished disk. Above the mold 101 is shown the punch 104 with the hole 105 for the passage of the rod 103 during the pressing process.

In FIG. 12 shows the position of the punch 104 at the end of the pressing process, when the compressed springs 102 have formed the porous disk 106.

The compressor works as follows.

At normal temperature of the walls of the cylinder 1, the relay contacts are open, the electromagnet 13 is de-energized, and the spring 27 holds the rod 12 in the position shown in FIG. 1. In this case, recess 17 connects the suction valve 7 to the gas source, and recess 18 connects the discharge valve 8 to the gas consumer.

With the reciprocating movement of the piston 2, the working cavity 5 of the compressor changes its volume, with an increase in which gas is sucked through valve 7, and with a decrease, gas is compressed and injected through valve 8.

When the gas is compressed, it heats up, which is the stronger, the higher the ratio of discharge pressure to suction pressure. In this case, the heat of compression is transferred to the walls surrounding the compression chamber 5, and they heat up, heating the suction gas, as a result of which the gas heats up even more during compression, which worsens the efficiency of the compressor.

As soon as the wall temperature exceeds the value specified by the setting of the relay 16, its contacts are closed, the electric current from the source 15 is supplied to the winding 14 of the electromagnet 13, and it draws the rod 12, shifting it to the left according to the drawing (see Fig. 2). In this case, recess 17 connects channel 21 for supplying liquid 9 from tank 10 with suction valve 7, and recess 18 connects discharge valve 8 with channel 24, in which throttle 25 and heat exchanger 26 are located. Channels 22 and 23, connected with the source and consumer of gas, at the same time, they are cut off from valves 7 and 8 and, consequently, from the working chamber 5.

Now the reciprocating movement of the piston 2 leads to the transition of the compressor to the pump mode, and the fluid 9 begins to circulate in a closed circuit (tank 9) → (compression chamber 5) → (throttle 25) → (heat exchanger 26) → (tank 9).

The liquid pressure during suction depends on the parameters of the suction tract and is close to atmospheric pressure. The compression and discharge pressure is determined mainly by the hydraulic resistance of the throttle 25 and the heat exchanger 26. It can be adjusted by changing the flow area of the throttle to such a value at which the liquid in the compression-discharge process begins to actively fill the pores of the sleeve 11 and disk 31 and cool them, cooling , thus, the walls of the compression chamber 5.

Considering that the specific heat capacity of, for example, water (when used as a coolant) is 4.2 kJ / kg K, and the specific heat capacity of most metals from which a porous sleeve and a porous disk can be made is only about 0, 3-0.4 kJ/kg·K, the cooling of the sleeve 11 and the disc 31 is very fast.

When the temperature of the walls of the compression chamber 5 reaches the value determined by the setting of the relay 16, it disconnects the electromagnet 13 from the electric current source 15, and the rod 12 moves to the right in the figure, taking the position shown in Fig. 1, the device switches back to the compressor mode.

At the same time, coolant remains in the porous material of the sleeve 11 and disk 31, the amount of which depends on the porosity of the material from which they are made, and during compression, when the gas temperature is high, the liquid actively evaporates, taking away the heat of evaporation from the material of the sleeve and disk , which prolongs the operation of the compressor at normal temperature of the walls of the compression chamber 5.

In the event that the porous material of the sleeve and disk has the properties of an adsorbent, and during the operation of the compressor adsorbed liquid, then after switching to the compressor mode, the desorption process begins, which also goes with the absorption of heat and enhances the cooling process of the material of the sleeve 11 and disk 31, prolonging the operation of the compressor in normal thermal conditions.

The operation of the compressor, the cylinder-piston group of which is shown in Fig. 3 assumes the use of ordinary structural materials as the porous material of the sleeve, including those having properties that porous structures are deprived of. One of these properties is the possibility of machining the inner surface of the sleeve after assembling it with the cylinder without clogging the channels, which makes it possible to obtain high-precision piston-cylinder pairs. In addition, after removal from the cylinder, such a sleeve can be disassembled and washed during scheduled preventive maintenance, which prolongs the overall life of the compressor.

The same can be said about the structure shown in Fig. 5. Its advantage is the almost impossibility of clogging the channels through which the liquid "impregnates" the material of the sleeve, since each compression-injection stroke of the liquid is accompanied by the opening of the joints between the elements (coils) that form the capillary channels. In this case, in addition to the effect of active cooling of the sleeve 5, there is a “washing” of rough surfaces.

The supply of the piston bottom with porous discs of various designs (Fig. 7, 9) allows you to increase the area of the compression chamber 5, provided with a layer of porous material and improve the cooling of the cylinder-piston group.

The production of porous material from a wire tangle and sections of springs (waste in the production of springs of various designs) makes it possible to reduce the cost of production of compressors of this design.

Thus, the proposed method of operation and the arrangement of a reciprocating compressor with regenerative cooling can significantly reduce the time required for cooling its cylinder-piston group, reduce energy costs for this process, i.e. increase the cooling efficiency of the parts of the cylinder-piston group, reduce the specific energy consumption and increase the efficiency of the compressor.

Therefore, it should be considered that the set technical task is fully completed.

Claims (9)

1. The method of operation of a reciprocating compressor with regenerative cooling, which consists in alternately compressing and injecting a liquid and gaseous medium into the working chamber of the cylinder, while alternately connecting the cylinder to sources of liquid and gaseous medium, and the cylinder liner is made of a porous material, characterized in that that the piston head, facing the compression and discharge chamber, is covered with a porous material, while during the compression and injection of the liquid, part of it is placed in the porous materials of the sleeve and the piston head. 2. A piston compressor for implementing the method according to claim 1, containing a cylinder with a sleeve made of porous material with a piston placed in it, connected to the reciprocating movement mechanism and forming a compression chamber with the cylinder and the valve cover, which, through a distributor, alternately connecting this chamber through self-acting check valves located in the valve cover of the cylinder, with a source of gas and liquid, characterized in that the piston head facing the compression chamber is covered with a porous material, while the porous materials of the sleeve and piston are made with the possibility of placing liquid in them on during its compression and injection. 3. The compressor according to claim 2, characterized in that porous adsorbents, such as silica gels or zeolites, are used as porous material. 4. Compressor according to claim 2, characterized in that the porous material of the sleeve is formed by a package of discs compressed along the axis of the cylinder with rough end surfaces that form capillaries upon contact. 5. The compressor according to claim 2, characterized in that the porous material of the sleeve is formed by a compression spring, the coils of which are in the form of a rectangle, and on the surface of the rectangle, perpendicular to the axis of the spring, roughness is applied, and this spring, in the state installed in the cylinder, is compressed in the axial direction to contact of the aforementioned rough surfaces, upon contact of which capillaries are formed. 6. Compressor according to claim. 2, characterized in that the porous material of the bottom is formed by fixed concentric rings pressed on each other, the inner and outer cylindrical surfaces of which have roughness, forming capillaries upon contact. 7. Compressor according to claim. 2, characterized in that the porous material of the bottom is formed by a fixed disc. 8. Compressor according to claim 7, characterized in that the disk is made of a wire tangle by pressing it in the form of a disk. 9. Compressor according to claim 7, characterized in that the disk is made of compression springs by pressing them into a mold.