JP2648938B2 - Multi-stage reciprocating compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-stage reciprocating compressor having an unload mechanism for reducing a power load on a driving source.

(Prior Art) In recent years, compressed air and other compressed gases used as power sources for machines have been increasingly required to have higher pressure. In order to deal with this, conventionally, FIGS. 3 and 4
A multi-stage reciprocating compressor as shown in the figure is often used.

In this multi-stage reciprocating compressor, a first cylinder 2 of a low-pressure side compression unit and a second cylinder 3 of a high-pressure side compression unit are connected to a crankcase 1. The pistons 4 respectively housed in the first cylinder 2 and the second cylinder 3 are connected to a crankshaft 6 via connecting rods 5 and each of the cylinder heads 7, 8
Are provided with suction chambers 9,10 and discharge chambers 11,12. The discharge chamber 11 on the low pressure side and the suction chamber 10 on the high pressure side are connected to an intermediate pipe.
Connected at 13. Therefore, the gas sucked from the suction chamber 9 on the low pressure side through the filter 14 is compressed to the intermediate pressure in the first cylinder 2 and then the gas is discharged from the discharge chamber 11 to the intermediate pipe.
It is sent to the suction chamber 10 on the high pressure side through 13 and is further compressed to a high pressure in the second cylinder 3 and stored in the tank 15. In addition, the suction valves 16, 17 are provided in the suction chambers 9, 10 on the low pressure side and the high pressure side, respectively.
Unloaders 18 and 18 'for properly opening the unloader are mounted. The unloaders 18 and 18 'are for reducing the power load of the compressor, and as shown in FIG.
Are constantly urged upward by a spring 20, and a compressed gas introduction pipe 21 is attached above the unload piston 19. When the pressure in the tank 15 reaches a predetermined value, compressed gas is introduced into the introduction pipe 21 to push down the unload piston 19 against the force of the spring 20 and open the suction valves 16 and 17. In FIG. 4, reference numeral 22 denotes a valve seat plate. The valve seat plate 22 is provided with an oblong suction hole. Near the center of the hole in the longitudinal direction, the tip of the unloading piston 19 is provided. Protrusions 23 as stoppers are formed so as to face 19a from both sides. The protrusion 23 regulates the amount of protrusion of the tip 19a by contacting the step 19b of the unload piston 19.

(Problems to be Solved by the Invention) However, in the conventional multi-stage reciprocating compressor described above, each of the unloaders 1 in the low-pressure side compression section and the high-pressure side compression section.
Since the introduction pipes 21 of 8, 18 'are 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, the low pressure side first cylinder 2
, A low pressure (atmospheric pressure in the case of air) is introduced, but the intermediate pressure inside the intermediate pipe 13 and the suction chamber 10 remains in the second cylinder 3 on the high pressure side. Here, while the unloaders 18, 18 'operate, the pistons 4 on the low pressure side and the high pressure side
In the second cylinder 3 filled with a gas having a high pressure and a large specific weight, the suction valve 17 is greatly affected by the internal pressure fluctuation. As a result, when the pressure of the second cylinder 3 rises, the suction valve 17 is momentarily pushed upward and the piston 4
In some cases, the unload piston 19 repeatedly moves up and down along with the vertical movement of so-called chattering.

If the chattering occurs frequently, the tip of the unload piston 19 that comes into contact with the valve seat plate 22 is significantly worn, resulting in a problem that the product life is shortened.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-stage reciprocating compressor capable of extending the life of a product by preventing vibration of an unloader portion in a high-pressure side compression section during an unload operation.

(Means for Solving the Problems) According to the present invention, as a means for solving the above-described 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. In a multi-stage reciprocating compressor provided with unloaders for keeping the valves of the suction chambers open in the side compression section and the high pressure side compression section, the operation timing of the low pressure side unloader is shorter than the operation timing of the high pressure side unloader. A delay means is provided for delaying.

(Operation) With this configuration, the suction, compression, and discharge operations of the gas are continued in the high-pressure side compression unit for a while after the unloader operates in the low-pressure side compression unit. For this reason, the pressure in the intermediate pipe decreases, and when the pressure is sufficiently reduced, the unloader of the high-pressure side compression unit operates. As a result, the high-pressure side compression unit performs the unload operation while maintaining the inside at a low pressure.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1, 2 and 4. It should be noted that FIG. 4 used in the description of the prior art is the same as that of the prior art because it is the same component, and the same parts as in the prior art are denoted by the same reference numerals, and the description of the overlapping parts is partially omitted. I 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 1 in exactly the same manner as the conventional one described above. The discharge chamber (not shown) of the cylinder head 7 on the side and the suction chamber 10 of the cylinder head 8 on the high pressure side are connected via an intermediate pipe 13. The two-stage compression by the first cylinder 2 and the second cylinder 3 is performed by the same internal mechanism as the above-described conventional one. Further, unloaders 18 and 18 'having unload pistons 19 are mounted in the suction chambers 9 and 10 on the low pressure side and the high pressure side, respectively, for introducing compressed gas for operating the unloaders 18 and 18'. The introduction pipe 21 is connected to the same pressure source (for example, via a pressure regulating valve to a tank for storing compressed gas).

The configuration up to this point is the same as the conventional one, but the multi-stage reciprocating compressor according to the present invention includes a device 24 as a delay means for delaying the transmission of pressure in the introduction pipe 21 from the low pressure side to the high pressure side. Is connected. This device 24
As shown in the figure, connection screw portions 25 are formed at both ends, and an orifice 26 and an expansion chamber 27 are formed adjacent to each other inside the center. 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 for preventing clogging is provided at the end of the orifice 26 on the low pressure side.
Is installed.

For the sake of convenience, the introduction pipe 21 has a pipe A connecting the pressure source and the unloader 18 on the low pressure side, a pipe B connecting the unloader 18 and the tool 24, and a pipe B connecting the unloader 18 and the tool 24, and The conduit connecting the unloader 18 'is called C.

In the above configuration, when the compressed gas storage tank reaches a predetermined pressure, the compressed gas for operating the unloaders 18 and 18 ′ is supplied to the pipelines 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, but the compressed gas supplied to the pipe B is throttled by the orifice 26, fills the expansion chamber 27, and then is supplied to the pipe C. Through the unloader 18 '. For this reason, the high-pressure side unloader 1
8 'opens the suction valve 17 at a timing later than the unloader 18 on the low pressure side.

When the unloader 18 on the low pressure side opens the suction valve 16, the suction chamber 9 is opened.
Then, a low-pressure gas is introduced into the first cylinder 2 (when compressed air is used as the compressed gas, the atmosphere is introduced via the filter 14). Here, the pressure of the intermediate pipe 13 is higher than the pressure of the first cylinder 2. After this,
In the high-pressure side compression unit, the suction, compression, and discharge of gas are continuously performed until the unloader 18 'operates, so that the pressure in the intermediate pipe 13 and the inside of the suction chamber 10 gradually decreases. Thereafter, when the unloader 18 'on the high pressure side is operated and the suction valve 17 is opened, the pressure of the suction chamber 10 is introduced into the second cylinder 3, and the second cylinder 3 is brought into a low pressure state.

As a result, the suction valve 17 is hardly affected by the pressure fluctuation inside the second cylinder 3 due to the operation of the piston 4, and the vibration of the unload piston 19, that is, the chattering is reliably prevented. Since chattering is eliminated, wear at the tip of the unload piston 19 is significantly reduced. Further, in the related art, due to the wear of the unload piston 19, the tip thereof abnormally protrudes from the guide portion 23 of the valve seat plate 22 shown in FIG. Such troubles do not occur. Further, if an instrument 24 as a delay means is interposed in the middle of the introduction pipe 21 as in this embodiment, the multistage device according to the present invention can be obtained by only slightly improving the introduction pipe compared to the conventional one. A reciprocating compressor can be obtained.

It should be noted that embodiments of the present invention are not limited to those described above.
May be provided or only the expansion chamber 27 may be provided.Also, the operation timing of the high-pressure side unloader 18 ′ may be delayed by introducing the compressed gas introduction pipe 21 from the low-pressure side compression section to the high-pressure side compression section. It may be extended.

(Effects of the Invention) As described in detail above, according to the present invention, the unload operation is performed while the high-pressure side compression unit maintains the low-pressure state similarly to the low-pressure side compression unit. Vibration in the unloader portion during operation is eliminated, and wear of parts due to the vibration is not generated. As a result, the life of the unloader is significantly extended.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part in the embodiment, FIG. 3 is a schematic sectional view showing a conventional technique, and FIG. FIG. 4 is an enlarged cross-sectional view corresponding to IV. 2 ... first cylinder (low pressure side compression section), 3 ... second cylinder (high pressure side compression section), 13 ... intermediate pipe, 18, 18 '... unloader, 24 ... equipment as delay means

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-8286 (JP, A) JP-A-58-47188 (JP, A) JP-A-58-47187 (JP, A) 138174 (JP, U)

Claims (1)

(57) [Claims] 1. 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 the valves of each suction chamber are kept open to the low-pressure side compression section and the high-pressure side compression section. A multi-stage reciprocating compressor provided with an unloader, wherein delay means for delaying the operation timing of the low-pressure side unloader from the operation timing of the high-pressure side unloader is provided.