JP4837907B2 - Reciprocating compressor - Google Patents

Description

  The present invention relates to a reciprocating compressor that can be suitably implemented as, for example, a hydrogen compressor.

  This type of reciprocating compressor reciprocates a drive piston through a connecting rod connected to a crankshaft that is driven to rotate by an electric motor or the like, and reciprocates a plunger by following the drive piston, thereby The fluid volume such as air and gas is compressed by the change in the space volume.

  Conventionally, the following three types of compressors have been developed as such reciprocating compressors (see, for example, Non-Patent Document 1).

That is, the first type is a reciprocating compressor in which a drive piston and a plunger are integrally formed or fixed. The second type is a reciprocating compressor in which a drive piston and a plunger are separated and formed as independent parts. The third type is a reciprocating compressor in which a drive piston and a plunger are coupled so as to be freely movable with respect to misalignment and angular misalignment. The second and third types of plungers are free plungers formed separately from the drive piston.
Ito et al., 3 other authors, "Practical machine series, positive displacement compressor", 6th edition, Sangyo Tosho Co., Ltd., April 5, 1979, p. 48.

  However, in the first type, since the fluctuating force from the connecting rod that converts the rotational movement of the crankshaft to the reciprocating action acts on the driving piston, the reciprocating movement of the driving piston is not an exact linear movement, Since it is transmitted to the plunger, the plunger that needs to maintain a minute gap is in strong contact with the cylinder wall surface, and there is a problem that seizure may occur due to this contact.

  In the second type, since the plunger is separated from the movement of the drive piston, the plunger does not come into strong contact with the cylinder wall surface. However, when there is no pressure difference between the compression side and the back pressure side of the plunger, for example, immediately after activation, etc. The plunger is separated from the drive piston and cannot be driven, and the plunger function may be lost.

  Further, the third type has a problem that in an unstable pressure state immediately after startup, vibration is generated by play of the connecting portion, and the connecting portion may be broken due to the vibration. .

  Therefore, the present invention provides a reciprocating compressor that can prevent the plunger from sticking to the cylinder wall surface and can ensure accurate operation of the plunger even in an unstable pressure state such as immediately after startup. It is aimed.

In order to achieve the above-described object, the invention according to claim 1 includes a drive piston and a free plunger separated as mutually independent parts, wherein one side of the free plunger is a compression chamber and the other side of the drive piston is arranged. In the reciprocating compressor having a back pressure space, the compression chamber is controlled so as to be constantly at a higher pressure than the back pressure space by communicating with the suction gas passage and the pressure control gas introduction passage. The control gas introduction passage introduces a gas having a pressure higher than the pressure in the back pressure space into the compression chamber.

  For this reason, in the invention described in claim 1, the compression chamber is controlled so as to be always at a higher pressure than the back pressure space by introducing the high pressure gas from the pressure control gas introduction passage. When the drive piston moves forward, the free plunger is pushed by the drive piston against the pressure in the compression chamber and moves in a direction to reduce the volume of the compression chamber, compresses the gas in the compression chamber, and compresses the gas. Deliver at a predetermined pressure. When the drive piston moves backward, the free plunger moves in the direction of enlarging the volume of the compression chamber following the movement of the drive piston while closely contacting the drive piston due to the pressure of the compression chamber, and sucks gas into the compression chamber. .

The invention according to claim 2 is the reciprocating compressor according to claim 1, wherein the back pressure space communicates with a pressure control gas discharge passage and is controlled to be always at a lower pressure than the compression chamber. It is characterized by being.

For this reason, in the invention described in claim 2 , the high pressure gas is introduced into the compression chamber via the pressure control gas introduction passage, and the gas flowing into the back pressure space is introduced into the back pressure space via the pressure control gas discharge passage. Discharge outward. As a result, the compression chamber is always at a higher pressure than the back pressure space.

The invention according to claim 3 is the reciprocating compressor according to claim 1 or 2 , wherein the gas introduction pressure from the pressure control gas introduction passage is controlled to be higher than the pressure in the back pressure space. The first pressure control valve is provided in the pressure control gas introduction passage.

For this reason, in the invention described in claim 3 , since the gas introduction pressure from the pressure control gas introduction passage is controlled to be higher than the pressure in the back pressure space by the first pressure control valve, the gas flow into the compression chamber is controlled. Inhalation can be performed without hindrance, and good followability of the free plunger with respect to the drive piston can be ensured.

The invention according to claim 4 is the reciprocating compressor according to any one of claims 1 to 3 , wherein a check valve is provided in the pressure control gas introduction passage.

Therefore, in the invention described in claim 4 , after the operation is started, when the compression chamber is pressurized and the gas suction pressure becomes higher than the pressure control gas introduction pressure, the gas flows backward through the pressure control gas introduction passage. In some cases, this back flow of gas can be prevented by a check valve provided in the pressure control gas introduction passage.

The invention of claim 5, wherein, there is provided a reciprocating compressor according to claim 2 Symbol placement, the second pressure control valve for discharging the gas in between the back pressure space when the back pressure becomes constant pressure, It is provided in the pressure control gas discharge passage.

For this reason, in the invention described in claim 5 , the back pressure and the suction gas pressure can be balanced by discharging the gas in the back pressure space by the second pressure control valve. Backflow into the back pressure space can be prevented.

  According to the first aspect of the present invention, the compression chamber is controlled so as to be always at a higher pressure than the back pressure space by introduction of the high pressure gas from the pressure control gas introduction passage. Regardless of this, since it moves following the movement of the drive piston while being in close contact with the drive piston due to the pressure in the compression chamber, it is possible to prevent the plunger from sticking to the cylinder wall surface, and unstable pressure immediately after startup, etc. A reciprocating compressor that can ensure accurate operation of the plunger even in a state can be provided.

According to the second aspect of the present invention, the gas flowing into the back pressure space from the compression chamber can be discharged to the outside of the back pressure space through the pressure control gas discharge passage. The pressure can be reliably maintained at a higher pressure than the back pressure space, and in addition to the effect of the first aspect of the invention, more accurate operation of the free plunger can be ensured.

According to the third aspect of the present invention, the first pressure control valve provided in the pressure control gas introduction passage allows the gas to be sucked without hindrance and has a good followability to the drive piston of the free plunger. Therefore, in addition to the effects of the first or second aspect of the invention, the free plunger can exhibit a better plunger function.

Further, according to the fourth aspect of the invention, it is possible to prevent the backflow of gas through the pressure control gas introduction passage by the check valve, according to claim 1 to 3 of the invention according to any one of In addition to the effect, gas can be sucked and discharged accurately.

According to the invention of claim 5, wherein the second pressure control valve provided in the pressure control gas discharge passage, the intake gas can be prevented from flowing back into the back pressure space, claim 2 Symbol In addition to the effects of the present invention, gas can be sucked and discharged more accurately.

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

  FIG. 1 shows a reciprocating compressor 10 as a first embodiment of the present invention. The compressor 10 includes a drive piston 2 and a free plunger 1, and is configured such that one of the free plungers 1 is a compression chamber R1 and the other is a back pressure space R2, and the compression chamber R1 is a pressure control gas introduction passage L1. , And is controlled so as to be constantly at a higher pressure than the back pressure space R2. The free plunger 1 is formed as a separate part from the drive piston 2 as in the conventional second type.

  The compression chamber R <b> 1 is defined by closing the upper opening of the cylinder 8 with a block 9, and a suction valve 6 and a discharge valve 7 are provided in the block 9. The pressure control gas introduction passage L1 communicates with the compression chamber R1 by communicating with the suction gas passage L2 communicating with the suction valve 6. The discharge valve 7 communicates with the discharge gas passage L3. For example, the pressure control gas introduction passage L1 introduces a gas having a pressure higher than the pressure in the back pressure space R2 from a discharge gas tank 21 provided in communication with the discharge gas passage L3. A gas cylinder (not shown) installed separately is used in place of the discharge gas tank 21 in order to cope with the initial pressure increase at the beginning of operation without pressure on the discharge side.

  The back pressure space R <b> 2 is formed as a space in which the crankshaft 4 of the crankcase 5 connected to the lower end of the cylinder 8 is set, and the atmosphere is passed through an opening 20 provided in the crankcase 5. It is open to. The crankshaft 4 is connected to the drive piston 2 via the connecting rod 3.

  In the compressor 10 configured as described above, the rotational motion of the crankshaft 4 is converted into the reciprocating motion of the drive piston 2 via the connecting rod 3, and the separated free plunger 1 is pushed and compressed by the tip of the drive piston 2. The gas is compressed by reducing the volume of the chamber R1, and the gas is sent out from the discharge valve 7 at a predetermined pressure.

  Further, when the drive piston 2 is retracted, the free plunger 1 keeps the pressure in the compression chamber R1 higher than the back pressure space R2 side, so that the movement of the drive piston 2 is performed in close contact with the drive piston 2. Following this, the volume of the compression chamber R1 is increased, whereby gas is sucked from the suction valve 6.

  Thus, the compressor 10 can move the gas of a predetermined pressure by repeating the suction and delivery of the gas. At this time, the plunger 1 moves following the movement of the driving piston 2 while being in close contact with the driving piston 2 due to the pressure of the compression chamber R1 in spite of being free. In addition to preventing this, it is possible to ensure accurate operation of the plunger 1 even in an unstable pressure state such as immediately after startup.

  FIG. 2 shows a reciprocating compressor 11 as a reference example of the present invention. The compressor 11 includes a drive piston 2 and a free plunger 1, and is configured such that one of the free plungers 1 is a compression chamber R1 and the other is a back pressure space R2, and the back pressure space R2 is a pressure control gas discharge passage. The entire structure is configured by communicating with L4 and being controlled so as to be always at a lower pressure than the compression chamber R1.

  The compressor 11 is the same as the compressor 10 except that the pressure control gas discharge passage L4 is provided instead of the pressure control gas introduction passage L1 (see FIG. 1). The pressure control gas discharge passage L4 is provided in communication with an opening 20 provided in the crankcase 5.

  The compressor 11 configured in this way passes the fitting gap between the free plunger 1 and the cylinder 8 and flows the gas flowing from the compression chamber R1 into the back pressure space R2 through the pressure control gas discharge passage L4. Since it can be discharged to the outside of the space R2, the back pressure space R2 is controlled to be always at a lower pressure than the compression chamber R1.

  As a result, the compressor 11 operates in the same manner as the compressor 10 as the free plunger 1 moves forward and backward of the drive piston 2, and thereby the same effects as the compressor 10 can be achieved.

FIG. 3 shows a reciprocating compressor 12 as a second embodiment of the present invention. The compressor 12 is configured in the same manner as the compressor 10 except that the compressor 12 includes both the pressure control gas introduction passage L1 and the pressure control gas discharge passage L4.

  That is, in the compressor 12, the compression chamber R1 communicates with the pressure control gas introduction passage L1, the back pressure space R2 communicates with the pressure control gas discharge passage L4, and the compression chamber R1 is connected to the back pressure space R2. Also, the pressure is always controlled to be high.

  In this configuration, the high pressure gas is introduced into the compression chamber R1 via the pressure control gas introduction passage L1, and the gas flowing into the back pressure space R2 from the compression chamber R1 is returned to the back pressure space via the pressure control gas discharge passage L4. It can be discharged to the outside of R2.

  For this reason, according to the compressor 12, the pressure of the compression chamber R1 can always be maintained at a higher pressure than the back pressure space R2, so that more accurate operation of the free plunger 1 can be ensured.

FIG. 4 shows a reciprocating compressor 13 as a third embodiment of the present invention. The compressor 13 is provided with a first pressure control valve 22 in the pressure control gas introduction passage L1 for controlling the gas introduction pressure P1 from the pressure control gas introduction passage L1 to be higher than the pressure P2 of the back pressure space R2. The other configurations are the same as those of the compressor 10 described above except for the differences.

  In this configuration, the first pressure control valve 22 controls the gas introduction pressure P1 from the pressure control gas introduction passage L1 so as to be higher than the pressure P2 in the back pressure space R2, so that gas is sucked into the compression chamber R1. Can be performed without hindrance and good followability of the free plunger 1 with respect to the drive piston 2 can be ensured.

  For this reason, according to the compressor 13, the free plunger 1 can show a favorable plunger function. The first pressure control valve 22 can be similarly attached to the pressure control gas introduction passage L1 of the compressor 12 (not shown), and also in this case, the same effect as the compressor 13 can be obtained.

FIG. 5 shows a reciprocating compressor 14 as a fourth embodiment of the present invention. The compressor 14 is different from the compressor 10 in that the check valve 23 is provided in the pressure control gas introduction passage L1.

  In this configuration, after the operation is started, when the compression chamber R1 is pressurized and becomes higher than the gas introduction pressure P1, the gas may flow backward through the pressure control gas introduction passage L1, but this gas backflow is reduced. This can be prevented by the check valve 23 provided in the pressure control gas introduction passage L1.

  For this reason, according to the compressor 14, the suction and discharge of gas can be performed accurately. The check valve 23 can be similarly attached to the pressure control gas introduction passage L1 of the compressors 12 and 13 (not shown), and in this case, the same operation effect as the compressor 14 can be obtained.

FIG. 6 shows a reciprocating compressor 15 as another reference example of the present invention. The compressor 15 is different only in that a second pressure control valve 24 that discharges gas in the back pressure space R2 when the back pressure P2 becomes a constant pressure is provided in the pressure control gas discharge passage L4. The other configuration is the same as that of the compressor 11 described above.

  In this configuration, the back pressure P2 and the suction gas pressure P3 can be balanced by discharging the gas in the back pressure space R2 by the second pressure control valve 24 provided in the pressure control gas discharge passage L4. As a result, the suction gas can be prevented from flowing back into the back pressure space R2.

For this reason, according to the compressor 15, gas can be sucked and discharged more accurately. Note that the second pressure control valve 24, also can be attached similarly to the pressure control gas discharge passage L4 of the compressor 12 (not shown), this case can also provide the same effects as the compressor 1 5.

FIG. 7 shows a reciprocating compressor 16 as still another reference example of the present invention. The compressor 16 is different from the compressor 16 only in that the drive piston 2 and the free plunger 1 are connected to each other by a connecting element 25 that can move freely with respect to mutual misalignment and angular misalignment. The reciprocating compressor 10 is configured in the same manner.

In this reference example , the connecting element is constituted by a protrusion 25 formed integrally with the drive piston 2, and is connected by engaging with a recess 26 formed in the free plunger 1. In this connected state, there is a fitting gap between the protrusion 25 and the recess 26, and the fitting gap can absorb mutual misalignment and angular deviation between the drive piston 2 and the free plunger 1. It has become.

This connecting element 25 corresponds to the third type of the prior art, but in this reference example , since the free plunger moves in a state where it is always pressed following the movement of the drive piston, Since there is no vibration even if there is, the connecting element 25 can function as a useful connecting element.

For this reason, according to the compressor 16 , the free plunger 1 connected by the connecting element 25 can exhibit a good plunger function.

  FIG. 8 shows a modified example of the connecting element. In this modification, the drive piston 2 is made of a magnetic material, the free plunger 1 and the cylinder 8 on which the free plunger 1 slides are made of a non-magnetic material, and the connecting element is the free plunger 1. The magnet 27 is provided on the contact surface with the drive piston 2. The magnetic body is, for example, iron, and the non-magnetic body is, for example, ceramic.

  In this configuration, the free plunger 1 and the drive piston 2 can be connected by being attracted to each other by the magnetic force acting between the magnet 27 and the drive piston 2. The magnet 27 at this time is configured as a connecting element that can freely move with respect to the misalignment and angular misalignment of the drive piston 2 and the free plunger 1, and can be destroyed even when an excessive external force is applied to the connecting portion. Safety can be ensured by separating them completely.

  For this reason, according to this modification, the free plunger 1 connected by the magnet 27 can exhibit a good plunger function, and at the same time, the durability of the connecting portion of the drive piston 2 and the free plunger 1 can be improved. Can do.

  The reciprocating compressors 13 and 14 described above are configured such that the pressure control gas discharge passage L4 having the pressure control gas discharge passage L4 or the second pressure control valve 24 communicates with the opening 20 of the crankcase 5. Also good. In this case as well, the above-mentioned specific operational effects corresponding to the pressure control gas discharge passage L4 or the pressure control gas discharge passage L4 provided with the second pressure control valve 24 can be taken into account.

It is a typical sectional view of a reciprocating compressor as a 1st embodiment of the present invention. It is a typical sectional view of a reciprocating compressor as a reference example of the present invention. It is a typical sectional view of a reciprocating compressor as a 2nd embodiment of the present invention. It is a typical sectional view of a reciprocating compressor as a 3rd embodiment of the present invention. It is a typical sectional view of a reciprocating compressor as a 4th embodiment of the present invention. It is a typical sectional view of a reciprocating compressor as other reference examples of the present invention. It is a typical sectional view of a reciprocating compressor as other reference examples of the present invention. It is a typical sectional view of an important section showing a modification of a connection element of a reference example of FIG.

Explanation of symbols

1 Free Plunger 2 Drive Piston 8 Cylinder 10-16 Compressor (reciprocating compressor)
22 1st pressure control valve 23 Check valve 24 2nd pressure control valve 25 Protrusion part (connection element)
27 Magnet (connecting element)
L1 Pressure control gas introduction passage L4 Pressure control gas discharge passage P1 Gas introduction pressure P2 Back pressure (pressure in the back pressure space)
R1 compression chamber R2 back pressure space

Claims (5)

In a reciprocating compressor comprising a drive piston and a free plunger separated as mutually independent parts, wherein one of the free plungers is a compression chamber and the other drive piston side is a back pressure space,
The compression chamber communicates with the pressure control gas introduction passage while communicating with the suction gas passage, and is controlled so as to always have a higher pressure than the back pressure space,
The reciprocating compressor characterized in that the pressure control gas introduction passage introduces a gas having a pressure higher than the pressure in the back pressure space into the compression chamber. The reciprocating compressor according to claim 1,
The reciprocating compressor is characterized in that the back pressure space communicates with a pressure control gas discharge passage and is controlled to be always at a lower pressure than the compression chamber. The reciprocating compressor according to claim 1 or 2,
A first pressure control valve for controlling a gas introduction pressure from the pressure control gas introduction passage to be higher than a pressure in the back pressure space is provided in the pressure control gas introduction passage. Reciprocating compressor. The reciprocating compressor according to any one of claims 1 to 3,
A reciprocating compressor characterized in that a check valve is provided in the pressure control gas introduction passage. The reciprocating compressor according to claim 2,
A reciprocating compressor characterized in that a second pressure control valve that discharges gas in the back pressure space when a back pressure becomes a constant pressure is provided in the pressure control gas discharge passage.

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