JPH0255884A - Multistage reciprocating compressor - Google Patents

Abstract

PURPOSE:To prevent any vibration in an unloader part at the high pressure side from occurring by making actuation timing of an unloader at the low pressure side later than that of the unloader at the high pressure side. CONSTITUTION:A discharge chamber of a cylinder head 7 at the low pressure side and a suction chamber 10 of a cylinder head 8 at the high pressure side are connected to each other via an intermediate pipe 13. Each of unloaders 18, 18' with an unload piston is installed in respective suction chambers 9, 10 at both low and high pressure sides. Compressed gas fed to a pipeline A is taken in the unloader 18 at the low pressure side at once, but another compressed gas fed to a pipeline B is taken in the unloader 18' via a delay means 24, so that it opens a suction valve at timing later than that of the unloader 18 at the low pressure side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-stage reciprocating compressor having an unloading mechanism that reduces the power load on a drive source.

(Prior Art) In recent years, compressed air and other compressed gases used as power sources for machines are increasingly required to be at higher pressures.

To cope with this problem, conventionally, multi-stage reciprocating compressors as shown in FIGS. 3 and 4 have been widely used.

In this multi-stage reciprocating dynamic pressure ll1li machine, a first crank 2 of a low-pressure side compression section and a second cylinder 3 of a high-pressure side compression section are connected to a crankcase l. Pistons 4 housed in the first cylinder 2 and the second cylinder 3 are connected to a crankshaft 6 via a connecting rod 5, and each cylinder head 7.8 has a suction chamber 9, a lO and a discharge chamber 11.12. Or is provided. The discharge chamber 11 on the low pressure side and the suction chamber IO on the high pressure side are connected by an intermediate pipe 13. Therefore, the gas sucked from the low-pressure side suction chamber 9 via the filter 14 is compressed to intermediate pressure in the first cylinder 2, and then sent from the discharge chamber 11 through the intermediate pipe 13 to the high-pressure side suction chamber IO. It is further compressed to a high pressure in the second cylinder 3 and stored in the tank 15. Further, each suction chamber 9.10 on the low pressure side and the high pressure side is equipped with an unloader 18.18° for appropriately opening the suction valve 16.17. This unrotor 18.18° is intended to reduce the power load on the compressor, and as shown in FIG. A compressed gas introduction pipe 21 is attached above the unloading piston 19, which is always elastically biased upward. When the pressure in the tank 15 reaches a predetermined value, compressed gas is introduced into the introduction pipe 21, the unload piston 19 is pushed down against the force of the splinter 20, and the suction valves 16 and 17 are opened. In addition, the reference numeral 22 in FIG. 4 is a valve seat plate, and an oblong suction hole is sunk into this valve seat plate 22, and an unload piston 19 is located near the center of the hole in the longitudinal direction. A protrusion 23 serving as a stopper is formed so as to face the tip 19a from both sides. This protrusion 23 comes into contact with the stepped portion 19b of the unloading piston 19 to restrict the protrusion I- of the tip +9a.

(Problem to be solved by the invention) However, in the conventional multistage reciprocating compressor described above, each unrotor 18 of the low pressure side compression section and the high pressure side compression section
．． Since the introduction pipe 21 of 18' is connected to the same pressure source, the unload pistons 19 on the high pressure side and the low pressure side operate almost simultaneously. For this reason, either low pressure (atmospheric pressure in the case of air) is introduced into the first cylinder 2 on the low pressure side, or the second cylinder 3 on the high pressure side is introduced between the intermediate pipe 13 and the inside of the suction chamber 10. Pressure will remain. Here, while the unrotor is operating at 18.18 degrees, the pistons 4 on the low pressure side and the high pressure side continue to operate, so in the second cylinder 3 filled with gas with high pressure and high specific weight, the suction valve 17 or become greatly affected by pressure fluctuations inside it. As a result, when the pressure of the second cylinder 3 increases, the suction valve 17 is momentarily pushed up in the L direction, and as the piston 4 moves up and down, the unloading piston 19 repeatedly moves up and down in small steps, creating a so-called chatter link. There were times when this happened.

If this chatter link occurs frequently, the tip of the unloading piston 19 that comes into contact with the valve seat plate 22 will wear out significantly, resulting in a shortened product life.

An object of the present invention is to provide a multistage reciprocating compressor that can extend the product life by preventing vibration of the unloader section in the high pressure side compression section during unloading operation.

(Means for Solving the Problems) The present invention provides, as means for solving the above-mentioned problems,
The discharge chamber of the low-pressure side compression section and the suction chamber of the high-pressure side compression section are connected by an intermediate pipe, and an unloader is provided in the low-pressure side compression section and the high-pressure side compression section to maintain the valves of each suction chamber in an open state. The multi-stage reciprocating compressor is provided with a d extension means for delaying the operation timing of the low-pressure side unloader from the operation timing of the high-pressure side unloader.

(Function) With this configuration, while the unrotor operates in the low-pressure side compression section, the operations of sucking, compressing, and discharging gas continue in the high-pressure side compression section for a while. Therefore, the pressure inside the intermediate pipe decreases, and when this pressure decreases sufficiently, the unloader of the high-pressure side compression section is activated. As a result, the high-pressure compression section performs unloading operation while maintaining its internal pressure at low pressure.

(Example) Hereinafter, an example of the present invention will be described in detail based on FIGS. 1.2 and 4. In addition, since FIG. 4 used to explain the conventional technology has the same constituent parts, it will be referred to as is, and the same parts as the conventional technology will be indicated by the same reference numerals, and the explanation of some overlapping parts will be omitted. do.

In the multi-stage reciprocating compressor according to the present invention, the first cylinder 2 of the high-pressure side compression section and the second cylinder 3 of the low-pressure side compression section are connected to the crankcase l, just like the conventional one described above, and the low-pressure Discharge chamber of side cylinder head 7 (not shown)
and the suction chamber 10 of the rad 8 are connected to the cylinder on the high pressure side via an intermediate pipe 13. The two-stage compression by the first cylinder 2 and the second cylinder 3 is performed by an internal mechanism similar to the conventional one described above. In addition, 1. Each suction chamber 9.10 on the low pressure side and high pressure side is equipped with an unrotor 18.18° having an unloading piston 19, and in order to introduce compressed gas for operating the unloader 18.18'. The inlet pipes 21 are connected to the same pressure source (for example, to a tank for storing compressed gas via a pressure regulating valve).

The configuration up to this point is the same as the conventional one, but the multistage reciprocating compressor according to the present invention includes a device as a delay means for delaying the transmission of pressure in the middle of the introduction pipe 21 going from the low pressure side to the high pressure side. 24 are connected. This instrument 24 is
As shown in FIG. 2, connecting threads 25 are formed at both ends, and an orifice 26 and an enlarged chamber 27 are formed adjacent to each other in the center thereof. The orifice 26 is located on the low pressure side, the expansion chamber 27 is located on the high pressure side, and a filter 28 is attached to the end of the orifice 26 on the low pressure side to prevent clogging.

For convenience of explanation below, the introduction piping 21 is designated as A, a pipe connecting the pressure source and the unloader 18 on the low pressure side, B, a pipe connecting the unloader 18 and the device 24, and a pipe connecting the device 24 and the high pressure side. The conduit connecting the unloader 18' will be called C.

In the above configuration, when the tank for compressed gas storage reaches a predetermined pressure, compressed gas for operating the unloaders 18 and 18' is supplied to the pipes A and B of the introduction pipe 21. The compressed gas supplied to the pipe A is immediately introduced into the unloader 18 on the low pressure side, or the compressed gas supplied to the pipe B is throttled in the orifice 26 and then filled in the expansion chamber 27 before being introduced into the pipe C. and is introduced into the unrotor 18°. Therefore, the high-pressure side unloader 18'' opens the suction valve 17 at a later timing than the low-pressure side unloader 18.

When the low-pressure side unloader 18 or suction valve 16 is opened, low-pressure gas is introduced from the suction chamber 9 into the first cylinder 2 (if compressed air is used as the compressed gas, atmospheric air is introduced via the filter 14). ). Here, the pressure in the intermediate pipe 13 becomes greater than the pressure in the first cylinder 2. After that, in the high-pressure side compression section, the open gas is continuously sucked, compressed, and discharged until the unrotor 18' operates, so the pressure inside the intermediate pipe 13 and the suction chamber 10 gradually decreases. To go. After this, unloader 1 on the high pressure side
8° operates and the suction valve 17 opens, the second cylinder 3
The pressure in the suction chamber 10 is introduced and becomes a low pressure state.

As a result, the suction valve 17 is hardly affected by pressure fluctuations inside the second cylinder 3 due to the operation of the piston 4, and vibration, that is, chattering, of the unloading piston 19 is reliably prevented. Since chattering is eliminated, wear at the tip of the unload piston 19 is significantly reduced. Furthermore, conventionally, due to wear of the unloading piston 19, the tip of the unloading piston 19 has been damaged by the valve seat plate 2 shown in FIG.
The trouble of abnormally protruding from the guide portion 23 of No. 2 and damaging the suction valve 17 has occurred rarely, and such trouble will no longer occur. In addition, as in this embodiment, the introduction pipe 2
1, the multi-stage reciprocating compressor according to the present invention can be obtained by only slightly improving the introduction piping compared to the conventional one. become.

Note that the embodiments of the present invention are not limited to those described above; for example, the delay means may include an orifice 2 in the device 24.
In addition, the compressed gas introduction pipe 21 from the low-pressure side compression section to the high-pressure side compression section may be arranged so that the operation timing of the high-pressure side unloader 18° is delayed. It may be extended to

(Effects of the Invention) As explained above in detail, according to the present invention, the high-pressure side compression section also performs unloading operation while maintaining the low pressure state like the low-pressure side compression section, so the unloading operation is performed while maintaining the low pressure state. There is no vibration in the unloader part during operation, and wear of parts due to this vibration does not occur. As a result, the life of the unloader is significantly extended.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the main parts of the same embodiment, Fig. 3 is a schematic sectional view showing a conventional technique, and Fig. 4 is the same as Fig. 3 FIG. 2... First cylinder (low pressure side compression section) 3... Second cylinder (high pressure side compression section) 13... Intermediate pine. 18, ]8°... unrotor, 24... appliance as delay means

Claims (1)

[Claims] (1) An unloader that connects the discharge chamber of the low-pressure side compression section and the suction chamber of the high-pressure side compression section with an intermediate pipe, and further maintains the valves of each suction chamber in the low-pressure side compression section and the high-pressure side compression section in an open state. A multi-stage reciprocating compressor comprising: a delay means for delaying the operation timing of the low-pressure side unloader from the operation timing of the high-pressure side unloader.