RU2703843C1 - Operating method of piston expander - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building, namely to three-dimensional machines, in particular, to piston expander-compressor units, and can be used in refrigeration engineering. Method of piston expander operation consists in supply of working medium through inlet channels to cylinder, in which piston connected to crank-and-rod mechanism is installed, further expansion of working medium with simultaneous drop of its temperature, displacement of piston and removal of working medium from cylinder through outlet channels. Main part of the working medium volume is discharged from the cylinder through the outlet openings located above the lower dead point of the piston, wherein the cavities of the openings are united by a common collector. Remaining part of working medium is compressed at back stroke of piston and directed through outlet channels, which cavity is connected to cavity of said collector of outlet openings through bypass valve, at that said valve is closed when working medium is supplied into cylinder and its remaining part is opened.

EFFECT: disclosed is the piston expander operation method.

1 cl, 3 dwg

Description

The invention relates to the field of mechanical engineering, namely: to volumetric action machines, in particular to piston expander-compressor units, and can be used in refrigeration equipment, for example, in air refrigeration units, air conditioning units, etc.

Known piston expander-compressor assemblies, including a piston compressor, a piston expander placed in one housing, having a common connecting rod and piston group with the location of the expander cylinder above the compressor cylinder and a forced gas distribution system for the expander [Expansion machines. Ed. K.I. Strakhovich - M. - L .: Engineering, 1966. p. 101-104].

Significant disadvantages of such expander-compressor units are the complexity of their design, high specific metal consumption, low operational reliability, as well as low operating efficiency due to heat inflows due to the close arrangement of the expander and compressor cylinders and the forced gas distribution mechanism of the expander.

Another design of the expander-compressor unit [2] is known, in which heat inflows from the side of the hot cylinder of the compressor to the cold cylinder of the expander are eliminated due to their separation by the intermediate chamber. However, the preservation of the forced expansion mechanism of the expander does not exclude the above disadvantages [Expansion machines. Ed. K.I. Strakhovich - M. - L .: Engineering, 1966. p. 101-104].

A known method of operation and a piston expander-compressor unit, including a piston compressor, a piston expander, placed in one housing, with connecting rod-piston groups attached to the crankshaft, in which the cylinder walls of the piston expander contain exhaust windows connected by a common manifold, and the inlet the valve is made normally open and is equipped with a locking element fixed to the spring. (RF patent No. 2134850, application No.. IPC: F25B 9/00, F25B9 / 06 - prototype),

The specified piston expander-compressor unit operates as follows. The compressor compresses the air drawn in from the atmosphere, while its temperature and pressure increase. Compressed air enters the refrigerator, where it is cooled at the inlet to the expander. When chilled compressed air is supplied through the nozzle, a part of it enters the cylinder through a normally open intake valve. The piston is at the top dead center and the outlet windows are closed. With the expiration of air in the gap between the seat and the shut-off element, an increase in the pressure drop above and below the shut-off element occurs. The valve, overcoming the elastic forces of the spring, closes, blocking the flow of compressed air into the cylinder. The part of the air that has got into the cylinder presses on the piston and when it moves it expands with decreasing temperature and completing external work. When the piston opens at the bottom dead center of the outlet windows, the expanding cooled air is pushed into the common collector and sent to the consumer. When the piston reaches top dead center, the pressure in the cylinder increases due to compression of the residual air. When the pressure in the cylinder is higher than the initial water pressure in the expander, the valve opens due to the spring elasticity, the cycle repeats.

The main disadvantage is that part of the working fluid remains in the cylinder after the stroke, is compressed during the reverse stroke of the piston and warmed up under compression, after which it is mixed with the cold working fluid received through the inlet channel and increases its temperature due to convective heat transfer, which reduces the efficiency of the expander.

The objective of the present invention is to remedy these disadvantages and increase the efficiency of the piston expander by removing the used working fluid from the cylinder during the reverse stroke.

This problem is solved due to the fact that in the proposed method of operation of the piston expander, which consists in feeding the working fluid through inlet channels to a cylinder in which a piston is connected, connected with a crank mechanism, subsequent expansion of the working fluid with a simultaneous drop in its temperature and the piston moving , and the removal of the working fluid from the cylinder through the exhaust channels, according to the invention, the main part of the volume of the working fluid is removed from the cylinder through the exhaust windows, which are located above the lower dead points of the piston, and the cavity of the windows is combined by a common manifold, and the remaining part of the working fluid is compressed during the reverse stroke of the piston and sent through the exhaust channels, the cavity of which is connected to the cavity of the said exhaust manifold collector through the bypass valve, while the said valve is closed when the working fluid is fed into the cylinder and open while compressing its remaining part.

The invention is illustrated by drawings, where in FIG. 1 shows a structural diagram of an expander in the initial period of time of the cycle, in FIG. 2 shows a structural diagram of an expander in the middle of the stroke, in FIG. 3 shows a structural diagram of an expander, in a finite period of time cycle.

The proposed method can be implemented using an expander having the following design.

The piston expander comprises a housing 1 with a cylinder 2, in which a piston 3 is mounted, connected with a crank mechanism 4. Inlet 5 and outlet 6 channels for the working fluid are located in the end part of the cylinder. Outlet windows 7 are made in the walls of the cylinder 2. Outlet windows 7 are located above the level of the bottom dead center of the piston 3 and are connected by a common collector 8. The cavity of the specified manifold 8 is connected to the cavity of the exhaust channel 6 by the bypass valve 9. To remove the working fluid from the manifold 8, channel 10.

The proposed method can be implemented as follows.

The working fluid under pressure through the inlet channel 5 is fed into the cylinder 2 and act on the piston 3 associated with the crank mechanism 4. After the inlet of the working fluid into the cylinder 2, the inlet 5 channel is closed. The exhaust channel 6 and the bypass valves 9 are closed at this time.

Under the influence of the pressure of the working fluid, the piston 3 moves from the inlet channel 5 to the bottom dead center with an increase in the volume of the cylinder, while an increase in the volume of the working fluid is accompanied by a decrease in its temperature. When the piston 3 reaches the bottom dead center, the outlet windows 7 open, and the main part of the working fluid enters the common manifold 8. The piston 3 starts to move upward and compresses the remaining part of the working fluid in the cylinder 2, while heating it. At this time, the outlet channel 6 and the bypass valve 9 are opened, and the remaining part of the working fluid is directed through their cavities into the cavity of the channel 10, where it is mixed with the main part and supplied for further use. After the piston reaches the top dead center, the exhaust channel 6 and the bypass valve 9 are closed, and the inlet channel 5 is opened to supply a new portion of the working fluid to the cylinder 2. Then the cycle repeats.

The proposed technical solution allows to increase the efficiency and operational reliability of the expander, to simplify the design, to reduce the specific metal consumption of the unit due to an increase in its productivity associated with a change in the temperature of the working fluid.

Claims (1)

The method of operation of the piston expander, which consists in feeding the working fluid through inlet channels to a cylinder in which a piston is connected, connected with a crank mechanism, the subsequent expansion of the working fluid with a simultaneous drop in its temperature, movement of the piston and removal of the working fluid from the cylinder through the exhaust channels, characterized in that the main part of the volume of the working fluid is withdrawn from the cylinder through the outlet windows, which are located above the bottom dead center of the piston, and the cavity of the windows are combined by a common collector m, and the remaining part of the working fluid is compressed during the reverse stroke of the piston and directed through the exhaust channels, the cavity of which is connected with the cavity of the said exhaust manifold collector through the bypass valve, while the said valve is closed when the working fluid is fed into the cylinder and opened when the remaining part is compressed.

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