JP2019143483A - Reciprocating compressor - Google Patents

Abstract

To prolong a replacement life of a rider ring arranged on a crosshead outer periphery of a reciprocating compressor using a crosshead piston.SOLUTION: A reciprocating compression crosshead piston using a crosshead piston has a piston part and a crosshead part. A plurality of piston rings is arranged on the outer peripheral surface of the piston part. A rider ring is arranged on the outer peripheral surface of the crosshead part. The crosshead piston has a space inside. The piston part has a first vent hole that exhausts blow-by through the internal space of the crosshead piston between the piston rings.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reciprocating compressor.

  Patent Document 1 (Japanese Patent Laid-Open No. 2017-66959) discloses an oil-free reciprocating compressor using a crosshead piston.

  The crosshead piston is provided with a rider ring as a sliding member in the crosshead portion. Since this rider ring is generally made of a resin such as PTFE, it wears as it slides on the inner peripheral surface of the cylinder and requires periodic replacement.

  In the case of a crosshead piston, the rider ring is exposed to hot blowby gas leaking from the piston ring during compression operation. Further, the rider ring bites wear powder generated from the piston ring. As a result, wear is promoted and the life is shortened.

  Patent Document 1 discloses a configuration in which a part of blow-by gas is discharged into the crankcase by providing a vent hole communicating with the crankcase on the upper surface of the crosshead portion.

JP2017-66959

  There is a case where blow-by gas is not sufficiently discharged from the vent hole of Patent Document 1. In particular, in the case of a crosshead piston, the flow path widens when blowby gas flows into the upper surface space of the crosshead portion. Since there is no great difference between the distance to the vent hole on the top surface of the crosshead and the distance to the rider ring on the side surface of the crosshead, it is difficult to discharge all blow-by with the expanded flow path from the vent hole. As a result, the rider ring exposed to high-temperature blow-by was worn out and had to be replaced in a short cycle.

  An object of the present invention is to extend the replacement life of a rider ring disposed on the outer periphery of a cross head of an oil-free reciprocating compressor using a cross head piston.

  The present invention includes a number of means for solving the above problems. For example, a cylinder, a cylinder head, a cross head piston that reciprocates in the cylinder, and the cross head piston can be swung. A connecting rod for supporting the connecting rod, a crankshaft for applying a rotational force to the end of the connecting rod, a crankcase for rotatably supporting the crankshaft, and a piston disposed on the outer peripheral surface of the piston portion of the crosshead piston A ring, and a rider ring disposed on an outer peripheral surface of the crosshead portion of the crosshead piston, wherein the crosshead piston is disposed between the position where the piston ring is disposed and the crosshead portion. It has a vent hole for exhausting blow-by through the inside of the head piston.

  ADVANTAGE OF THE INVENTION According to this invention, the replacement life of the rider ring arrange | positioned on the crosshead outer periphery of the oilless reciprocating compressor using a crosshead piston can be extended.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is a schematic diagram of a compressor of Example 1. FIG. It is the internal structure figure which looked at the compressor main part of Example 1 from the side. It is a figure which shows the detailed structural example of the crosshead piston part of Example 1. FIG. It is a figure which shows the detailed structural example of the crosshead piston part of Example 2. FIG. It is a figure which shows the detailed structural example of the crosshead piston part of Example 2. FIG. It is a figure which shows the detailed structural example of the crosshead piston part of Example 2. FIG. It is a figure which shows the detailed structural example of the crosshead piston part of Example 3. FIG. FIG. 6 is a diagram illustrating a configuration example inside a compressor body according to a fourth embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a compressor according to the first embodiment.

  The reciprocating compressor of the present embodiment includes a compressor main body 1, an electric motor 2 that drives the compressor main body 1, a tank 3 for storing the compressed fluid supplied from the compressor main body 1, and a common mount 8. These compressor main body 1, electric motor 2 and tank 3 are arranged and fixed on a common base 8 in this order from left to right in FIG.

  The compressor body 1 includes a compressor pulley 4, the electric motor 2 includes an electric motor pulley 5, and the compressor pulley 4 and the electric motor pulley 5 are wound around a transmission belt 6. As a result, the rotation of the electric motor 2 is transmitted through the electric motor pulley 5, the transmission belt 6, and the compressor pulley 4, and the compressor main body 1 compresses the fluid. Note that the compressor pulley 4 and the motor pulley 5 are provided with blades, and cooling air is generated by the blades toward the compressor body 1 and the motor 2 to cool the air. Further, the discharge port of the compressor body 1 and the tank 3 are connected by a pipe 7 having an electromagnetic valve 9 in the middle, and fluid is stored in the tank 3.

  FIG. 2 is an internal structural view of the compressor body of the first embodiment as viewed from the side. In addition, air, nitrogen, a carbon dioxide gas, or argon is contained in the fluid which the compressor of a present Example makes object.

  The outer shape of the compressor main body 1 is roughly divided into a crankcase 21, a cylinder 22, and a cylinder head 23 that closes the upper portion of the cylinder 22.

  The crankcase 21 includes a crankshaft 24 and a connecting rod 27. The crankshaft 24 is supported in a rotatable state in the crankcase 21 (for example, supported by a bearing), and a part of the crankshaft 24 is connected to the rotation shaft of the compressor pulley 4. The crankshaft 24 is connected to a connecting rod 27 extending toward the cylinder 22. Therefore, the rotational motion of the rotating shaft of the compressor pulley 4 can be transmitted to the connecting rod 27 via the crankshaft 24.

  The crankcase 21 includes a breathing filter 37 that communicates with the outside. This ventilation through the breathing filter 37 is an important function of cooling the entire compressor body 1 from the inside by breathing the internal space of the crankcase 21 against the outside air as the crosshead piston 25 reciprocates. do.

  Next, the cylinder 22 has a cylindrical shape divided into upper and lower stages of a small diameter compression chamber side cylinder 22a and a large diameter crankcase side cylinder 22b. The cylinder 22 supports a crosshead piston 25 connected to the connecting rod 27 in a reciprocating manner. The crankshaft 24 and the connecting rod 27 convert the rotational motion of the rotating shaft of the compressor pulley 4 into the reciprocating motion of the crosshead piston 25 in the direction perpendicular to the rotating shaft of the compressor pulley 4. In order to simplify the explanation in FIGS. 1 and 2, the shape of the compressor is a single-cylinder single-stage compressor having only one pair of pistons and cylinders. It may be a multi-cylinder single-stage compressor having a piston / cylinder or a multi-cylinder multi-stage compressor.

  The cylinder head 23 includes a suction chamber 23a and a discharge chamber 23b. Each chamber 23a, 23b is provided with a suction valve 29a and a discharge valve 29b. By the action of these air valves 28 (suction valve 29a and discharge valve 29b), the reciprocating motion of the crosshead piston 25 enables a series of compression operations of intake, compression, and discharge. Specifically, when the crosshead piston 25 descends, the pressure in the compression chamber decreases, and when the compression chamber falls below a certain pressure, the suction valve 29a is opened and intake is performed. Further, when the crosshead piston 25 rises, the suction valve 29a is closed, the pressure in the compression chamber rises, and when the compression chamber reaches a certain pressure or higher, the discharge valve 29a is opened and discharge is performed. The discharge valve 29a is closed when the pressure falls below a certain pressure.

  FIG. 3 is a diagram illustrating a detailed configuration example of the crosshead piston according to the first embodiment.

  In FIG. 3, the crosshead piston 25 has a cylindrical shape divided into two stages, a small-diameter piston portion 22a on the compression chamber side and a large-diameter crosshead portion 22b on the crankcase side.

  The piston portion 22a includes a piston large diameter portion on the compression chamber side and a piston small diameter portion connected to the cross head portion on the crank chamber side.

  Five annular grooves are formed on the outer periphery of the large-diameter portion of the piston, and five annular piston rings 33a to 33e for sealing the compression chamber in the compression process are fitted in these grooves. . The cross head portion 22b is reciprocated along the inner surface of the crankcase side cylinder 22b. The piston rings 33a to 33e provide a seal between the large diameter portion of the piston portion 25a and the compression chamber side cylinder 22a. ing. Since the number of the piston rings 33a to 33e is determined according to the pressure of the gas to be handled, a plurality of piston rings 33a to 33e may be used.

  Two annular grooves are formed on the outer periphery of the cross head portion 22b, and rider rings 34 are fitted into the grooves one by one. The rider ring 34 receives the side pressure generated as the crosshead piston 25 swings, and the cylinder gap 42 (crankcase side) that is the gap between the crosshead portion and the crankcase side cylinder 22b is maintained. The side cylinder 22b and the crosshead piston 25 are prevented from coming into direct contact with each other.

  The small end portion 35 of the connecting rod 27 is connected to the cross head portion 22b by a piston pin 35a, and the cross head portion 22b reciprocates along the inner surface of the large-diameter crankcase side cylinder 22b.

  With this structure, the sliding atmosphere of the rider ring is satisfied by the blow-by gas leaking from the piston ring. Under such conditions, the wear rate of the resin sliding material increases rapidly. In particular, when high-purity nitrogen gas is compressed, there is a possibility that the wear rate of the resin-made sliding material increases rapidly as compared with the case where normal air is compressed.

  Therefore, the interior of the piston portion 25a is hollowed out to provide an internal space 25a connected to the crankcase 21, and a first air vent 25b communicating with the crosshead piston internal space 25a is provided between the piston rings of the piston pin 35a. In the present embodiment, the first vent hole 25b is provided between the piston ring 33d and the piston ring 33e.

  Since the blow-by is sealed by the piston ring 33e, most of the blow-by gas leaking from the piston rings 33a to 33d does not flow into the upper space 45 of the rider ring 34, but the first vent hole 25b, cross It is discharged to the crankcase 21 through the internal space 25a of the head piston 25, and further discharged to the outside by the breathing filter. In this way, the oil-free reciprocating compressor using the crosshead piston of the present embodiment can suppress the influence of blow-by on the rider ring 34 and reduce the wear speed, so it is disposed on the outer periphery of the crosshead. The replacement life of the rider ring 34 can be extended.

  The blow-by gas contains wear powder of the piston rings 33a to 33d, but is exhausted through the first vent hole 25b, so that abrasive wear due to biting of the rider ring 34 into the sliding surface can be prevented. .

  The second embodiment has a configuration in which the wear resistance is improved as compared with the first embodiment.

  FIG. 4A is a diagram illustrating a detailed configuration example of the crosshead piston according to the second embodiment. This embodiment is different from FIG. 3 of the first embodiment in that a second ventilation hole 25c connected to the internal space of the crosshead piston 25 is provided between the piston ring 33d and the rider ring 34.

  In particular, the second vent hole 25c in FIG. 4 (a) is provided on the upper surface of the crosshead portion of the crosshead piston 25.

  In Embodiment 1, the blow-by gas leaking from the piston rings 33a to 33d is sealed by the piston ring 33e, so that most of the blow-by gas does not flow into the rider ring upper space 45 but passes through the second vent hole 25b. And is discharged into the crosshead piston internal space 25a.

  However, if the piston ring 33e is worn and its sealing performance is reduced, a small amount of blow-by gas may leak into the rider ring upper space 45 and increase the wear of the rider ring 34. Even in such a case, in order to reduce the wear of the rider ring 34, air is actively taken in the upper space 45 of the crosshead portion of the crosshead piston, which is the blowby path, and the gas purity is increased by the inflow of blowby gas. There is a need to prevent.

  Therefore, in this embodiment, as described above, the second ventilation hole 25c connected to the internal space of the crosshead piston 25 is provided between the piston ring 33d and the rider ring 34. During the operation of the compressor, the rider ring upper space 45 repeatedly expands and contracts as the crosshead piston 25 reciprocates. At the timing of this expansion, the rider ring upper space 45 has a negative pressure with respect to the crosshead piston internal space 25a. This negative pressure acts to suck up the fluid inside the crosshead piston inner space 25a and eventually the crankcase 21 through the second vent hole 25c. At this time, since the inside of the crankcase 21 is breathing outside through the breathing filter 37, the crankcase 21 is filled with a fluid whose main component is the same atmosphere as the installation environment. As a result, the rider ring upper space 45 sucks up the fluid whose main component is the same atmosphere as the installation environment from the second ventilation hole 25c, and lowers the gas purity in the sliding atmosphere of the rider ring 34. It becomes possible to improve the wear of 34.

  The second ventilation hole 25c in FIG. 4 (a) is provided on the upper surface of the crosshead portion of the crosshead piston 25, but on the crankcase side from the piston ring 33e arranged at the bottom and from the rider ring 34 to the compression chamber. Any position on the crosshead piston 25 may be used.

  Specific examples are shown in FIGS. FIG. 4B shows an example in which the second vent hole 25c is arranged on the side surface of the small-diameter portion of the piston portion instead of the upper surface of the crosshead portion of the crosshead piston 25. FIG. 4C shows an example in which the second ventilation hole 25c is arranged not on the upper surface of the crosshead portion of the crosshead piston 25 but on the small diameter portion of the piston portion (a region where the space between the piston portion and the compressor side cylinder is narrow). is there.

  The third embodiment has a configuration in which the wear resistance is further improved as compared with the first embodiment.

  FIG. 5 shows the configuration of the crosshead piston 25 of the third embodiment.

  In Example 1 or Example 2, the blow-by gas that has passed through the first vent hole 25b and the second vent hole 25b is discharged to the crosshead piston internal space 25a. This blow-by gas is hot due to compression heat. For example, when a bearing (not shown) fitted to the connecting rod small end 35 is a grease-filled bearing, the grease is heated to promote deterioration. there's a possibility that. In order to prevent this, the blow-by gas must be discharged to a position not in contact with the connecting rod small end portion 35. In the second embodiment, the second vent hole 25c is provided for the crosshead piston 25. In the third embodiment, the third vent hole 25d is additionally provided on the cylinder side connected to the rider ring upper space 45. There is.

  In the example of FIG. 5, the third vent hole 25d is provided in the upper part of the crankcase side cylinder 22a (lower part of the cylinder 22b on the compression chamber side) to communicate the rider ring upper space 45 with the outside. This is because the processing direction of the air holes substantially coincides with the direction of the inner diameter axis of the cylinder, and therefore there is an advantage that processing is easy. In order to obtain the following effects, it is only necessary to provide the third vent hole 25d on the cylinder side connected to the rider ring upper space 45.

  In the case of the present embodiment, during the operation of the compressor, the crosshead piston upper space 45 is breathed with the outside air not related to the crankcase and discharged by blow-by gas through the vent hole 25d. As a result, the connecting rod small end portion 35 is not heated by blow-by gas, and an increase in gas purity due to inflow of blow-by gas in the sliding atmosphere of the rider ring 34 can be prevented, and wear of the rider ring 34 is reduced. It becomes possible. That is, not only the wear of the rider ring 34 but also the reliability and durability of the bearing fitted into the connecting rod small end 35 can be improved.

  In order to promote breathing with outside air, the first vent hole 25b or the second vent hole 25c may be omitted.

  The fourth embodiment has a configuration in which noise characteristics (quietness) are further improved as compared with the third embodiment.

  FIG. 6 shows the configuration of the compressor body 1 of the fourth embodiment.

  In the third embodiment, the configuration in which the rider ring upper space 45 is breathed with the outside air through the third vent 25d has been described. However, when the compressor is actually operated in the configuration of the third embodiment, the vent 25d Intermittent breathing sound accompanying reciprocation is released to the installation environment. Some users may be concerned about this breathing sound.

  Although the third vent hole 25d of the third embodiment is an open end, in this embodiment, the third ventilation hole 25d is changed to a breathing pipe 46 that connects the rider ring upper space 45 and the crankcase.

  In the configuration of this embodiment, blow-by gas passes through the breathing pipe 46 from the rider ring upper space and is discharged into the crankcase 21. With this configuration, intermittent breathing due to the reciprocating motion is buffered by the internal volume of the crankcase 21, so that it is possible to reduce deterioration in noise characteristics.

  In the present embodiment, the blow-by gas passing through the breathing pipe 46 has a high heat due to compression heat. Therefore, if the blowby gas is discharged into the crankcase 21 as it is, there is a possibility that the temperature in the crankcase 21 is increased as in the problems of the first and second embodiments described in the third embodiment. is there. The increase in the temperature of the crankcase 21 increases the wear rate of the rider ring 34, which degrades the grease of each bearing inside the compressor body 1 such as the bearing supporting the crankshaft as well as the connecting rod small end 35 described above. There is also the possibility of letting

  As a countermeasure against this, the position through which the breathing pipe 46 passes is arranged so that the cooling air from the compressor pulley 4, for example, can dissipate heat until blow-by gas flows into the crankcase 21, and the crankcase 21 It is possible to suppress the temperature rise.

1 Compressor body, 2 Electric motor, 3 Tank, 4 Compressor pulley, 5 Motor pulley, 6 Transmission belt, 7 Piping, 8 Common mount, 9 Solenoid valve
21 Crankcase, 22 cylinder, 22a Compression chamber side cylinder, 22b Crankcase side cylinder, 23 Cylinder head, 23a Suction chamber, 24 Crankshaft, 25 Crosshead piston, 25a Crosshead piston internal space, 25b 1st vent hole, 25c 2nd vent hole, 25d 3rd vent hole, 27 connecting rod, 28 air valve, 29a suction valve, 29b discharge valve,
33a 1st piston ring, 33b 2nd piston ring, 33c 3rd piston ring, 33d 4th piston ring, 33e 5th piston ring, 34 rider ring, 35 connecting rod small end, 35a piston pin, 37 breathing filter, 41 Cylinder gap (compression chamber side), 42 Cylinder cap (crankcase side), 45 Rider ring upper space, 46 Breathing piping

Claims (11)

A cylinder, a cylinder head, a crosshead piston that reciprocates in the cylinder, a connecting rod that supports the crosshead piston in a swingable manner, a crankshaft that applies a rotational force to an end of the connecting rod, A crankcase that rotatably supports the crankshaft,
The crosshead piston has a piston portion and a crosshead portion,
A plurality of piston rings are arranged on the outer peripheral surface of the piston part,
A rider ring disposed on the outer peripheral surface of the crosshead portion;
The crosshead piston has a space inside,
2. The reciprocating compressor according to claim 1, wherein the piston part has a first air hole for exhausting blow-by through the space inside the crosshead piston between the piston rings. In claim 1,
A reciprocating compressor characterized in that a second vent hole for exhausting blow-by through the space inside the cross head piston is provided in a portion between the rider ring of the cross head portion and the piston ring of the piston portion. In claim 2,
The reciprocating compressor characterized in that the second vent hole is provided in a cross head portion of the cross head piston. In claim 2,
The reciprocating compressor characterized in that the second vent hole is provided in a piston portion of the crosshead piston. In claim 1,
A reciprocating compressor characterized in that the cylinder has a third vent hole in a portion between the rider ring of the crosshead portion and the piston ring of the piston portion. In claim 5,
A reciprocating compressor characterized by having a pipe through which the third ventilation hole and the crankcase communicate. In claim 6,
A reciprocating compressor, wherein the crankcase is connected to outside air. In claim 7,
The reciprocating compressor characterized in that the crankcase is connected to outside air through a breathing filter. In claim 5,
The reciprocating compressor characterized in that the third vent hole is connected to the outside air. In claims 1 to 4,
A reciprocating compressor characterized by comprising a breathing filter in the crankcase. In claim 1 to 10,
The reciprocating compressor characterized in that the cross head portion has a diameter larger than that of the piston portion.

Images