RU11312U1 - PISTON DETANDER - Google Patents

Abstract

1. A piston expander containing a cylinder with outlet windows, a piston, a cylinder cover, in which a normally open valve with a locking element in the form of a spring-loaded ring with a stopper is placed, an inlet fitting, characterized in that the stopper is movable relative to the inlet fitting and the cylinder cover .2. The piston expander according to claim 1, characterized in that a thread is made in the cylinder cover, inlet fitting and restrictor.

Description

PISTON DETANDER

The utility model relates to the field of mechanical engineering for volumetric machines, in particular, norsh expanders and can be used in refrigeration, for example, in air refrigeration units, air conditioning units.

Known piston expanders having a cylinder with a piston moving in it, a low-pressure gas distribution system in which the inlet and outlet valves are opened from the expander piston (expanders with internal valve drive) SP, pp. 128-130, 192-194, 21, p. 82-89. The timing of the closing of the inlet valve in such expanders is controlled by changing the spring force with the adjusting screw located in the cylinder cover of the expander.

The disadvantage of expanders with an internal valve drive is a rather complicated gas distribution system and, in connection with this, the high complexity of manufacturing and low operational reliability. In addition, such expanders have an increased dead volume, which reduces the efficiency of the expander workflow.

Known piston expanders having a cylinder with a piston and a gas distribution system with gas inlet and outlet through a channel system in the cylinder and piston (valveless expanders) i, pages 128-130, 196-199, 21, pages 81-82.

However, such expanders have low efficiency, especially when operating in modes other than nominal.

Another type of expander is known having a cylinder with a piston and a gas distribution system with a normally-open, self-acting inlet valve 31. Disadvantages due to the complexity and complexity of the gas distribution system are eliminated in this expander.

The disadvantage of this design of the expander is a decrease in operating efficiency in modes other than the nominal, due to the fact that the lift height of the shut-off element of a normally-open valve has a fixed value, calculated to close the valve at a certain point in time, determined by the required gas temperature at the outlet of the expander and cooling capacity. In such an expander, the optimal gas distribution law, corresponding to a higher efficiency of the expander, is performed with strictly limited inlet gas parameters (pressure and flow).

The objective of this utility model is to eliminate this drawback, namely, increasing the efficiency of the expander in operating modes other than the nominal one.

This problem is solved due to the fact that in the known piston expander containing a cylinder with outlet windows, a piston, a cylinder cover in which a normally-open valve with a locking element in the form of a spring-loaded ring are placed, a stopper, an inlet fitting, a stopper is mounted with the possibility of movement relative to inlet fitting and cylinder cover. To ensure the possibility of such movement in the cylinder cover, inlet fitting and restrictor, a thread is made.

The essence of the utility model is illustrated by the drawings, in which Fig. 1 shows a longitudinal section of an expander with a normally-open valve and outlet windows, and Fig. 2 shows indicator diagrams of the working processes of the expander in various operating modes.

The piston expander comprises a cylinder 1, coaxially to which a piston 2 is placed, connected with a crank mechanism. The cylinder 1 has outlet windows 3 arranged uniformly around the circumference of the cylinder, made, for example, in the form of round holes. In the cover 4, consisting of upper and lower parts, there is a normally open valve with a locking element 5 in the form of a ring spring-loaded with a coil spring 6. The lower part of the cover 4 with a specially machined surface serves as a saddle for the locking element 5. In the saddle holes 8 for gas passage are made. An inlet fitting 10 is screwed into the stop 9. To prevent the locking element 5 from moving in the radial direction, a cylindrical groove li is made in it, into which the upper end of the spring 6 mounted in the blind hole 12 of the lower part of the cover 4 is supported.

The expander works as follows. Compressed air through the nozzle 9 enters the cylinder 1 through a normally open valve. The piston 2 is at the top dead center

and exit windows 3 are closed. With the expiration of air in the gap between the saddle 7 and the locking element 5, an increase in the pressure drop above the locking element 5 and below it occurs (filling process 1-2 in figure 2). The valve, overcoming the elastic forces of the spring 6, closes (point 2 in FIG. 2a), blocking the flow of compressed air into the cylinder 1. The portion of air that has entered the cylinder puts pressure on the piston 2 and expands when it moves (process 2-3 in FIG. 2) with a decrease in temperature and the performance of external work. When the piston 2 opens at the bottom dead center of the exhaust windows 3, the expanded cooled air is pushed out (processes 3-4 and 4-5 in FIG. 2) into the low-pressure line and sent to the consumer. As the piston approaches the top dead center, the pressure in the cylinder increases due to compression of the residual air (process 5-1 in figure 2). When the pressure in the cylinder is equal to the pressure at the inlet to the expander, the intake valve opens by the action of the spring 5, the cycle repeats. When the operating mode of the expander changes, for example, when the pressure at the inlet of the expander decreases, the gas pressure force may not be enough to close the valve at the right time (about half the piston stroke), as a result of which the valve closes with a delay (point 2 in Fig. 26 ), which leads to incomplete expansion of the air and an increase in temperature at the outlet of the expander. With increasing pressure at the inlet to the expander, the gas pressure force is greater than the calculated value, and the valve closes prematurely (point 2 in FIG. 2c), which leads to a decrease in gas flow through the expander and a decrease in cooling capacity. The operation modes of the expander are regulated by moving the limiter relative to the inlet fitting and the cylinder cover along the threads, as a result of which the required temperature and cooling capacity are established.

The proposed technical solution allows to increase the efficiency of the expander in modes other than nominal.

SOURCES OF INFORMATION:

1. Cryogenic piston expanders. Nod red. A.M. Arkharova. M., Mechanical Engineering, 1974.

2.Bumagin G.I. Piston expanders. Omsk 1981,

3.Piston expander. Patent N 2029911, MKI F 25 V 1/02. Prilutsky I.K., Antonov N.M., Isakov V.P., Movchan E.P., Dengin V.G., Merkel N.D., Prilutsky A.K.

Claims (2)

1. A piston expander comprising a cylinder with outlet windows, a piston, a cylinder cover, in which a normally open valve with a locking element in the form of a spring-loaded ring with a stopper is placed, an inlet fitting, characterized in that the stopper is movable relative to the inlet fitting and the cylinder cover . 2. The piston expander according to claim 1, characterized in that a thread is made in the cylinder cover, inlet fitting and restrictor.