JP4291770B2 - air compressor - Google Patents

Description

  The present invention relates to an air compressor provided with an intake adjustment valve that operates using its own discharge pressure without relying on an external power source.

2. Description of the Related Art Conventionally, an air compressor provided with an intake adjustment valve that operates using its own discharge pressure is known (see, for example, Patent Documents 1 and 2).
JP-A-6-66284 (FIG. 1) JP-A-8-312564 (FIG. 1)

  Patent Document 1 discloses a compressor main body, an intake adjustment valve that is interposed in a suction flow path, operates a valve body using spring force and discharge pressure, and opens and closes the suction flow path. For controlling the intake adjustment valve, the other end communicates with a space in the intake adjustment valve, the other end of which is cut off from the valve body, and guides the discharge air from the compressor body to the space via the pressure adjustment valve. An air compressor including a flow path and an air discharge flow path for discharging discharged air to the atmosphere via an air discharge valve, an on-off valve, and a silencer is disclosed. If the discharge pressure becomes too high, the pressure adjustment valve is opened to reduce the opening of the intake adjustment valve, thereby adjusting the discharge pressure. In addition, when it is necessary to reduce the pressure on the discharge side in order to reduce the load on the compressor body, for example, when the compressor is restarted, the air release valve and the on-off valve are opened. The compressed air on the discharge side is released into the atmosphere from the discharge passage.

  Patent Document 2 discloses a compressor main body, an intake adjustment valve that is interposed in a suction flow path thereof, operates a valve body using spring force and discharge pressure, and opens and closes the suction flow path, and one end of a discharge flow path. The other end communicates with a space in the intake regulating valve, the other end of which is cut off from the valve body, and the discharge air from the compressor body is increased in the space via an electromagnetic valve and a flow resistance adjusting valve. An air compressor is disclosed that includes a flow air discharge path and a downstream air discharge path that discharges discharged air to the atmosphere through an air restrictor and a silencer from the space. And when making it transfer to an unloading state, the said solenoid valve is opened, the compressed air of a discharge flow path is guide | induced to the said space via the said flow path resistance control valve, and it vents | releases, and the said intake control valve Is closed. In this case, the flow path resistance adjustment valve adjusts the resistance of the upstream air discharge path according to the pressure of the discharge flow path, and corresponds to the start unloading and the air discharging unloading.

  In the case of the air compressor described in Patent Document 1, since each of the vent valve and the pressure regulating valve is separately provided, there is a problem that the piping becomes complicated and the number of parts increases.

  In the case of the air compressor described in Patent Literature 2, there is a problem that the structure of the flow path resistance control valve becomes complicated and the unload mechanism becomes complicated.

  The present invention has been made to eliminate such a conventional problem, and an object of the present invention is to provide an air compressor having a capacity adjustment mechanism with a simple configuration.

In order to solve the above-mentioned problem, the first invention is a compressor body and a valve body that is interposed in the suction flow path so as to be openable and closable, and is always urged by a spring force in a direction to close the suction flow path. And an intake adjustment valve having one end communicating with a space inside the intake adjustment valve having one end connected to the discharge flow path and the other end cut off from the valve body, and discharging air from the compressor body into the space. An air compressor having a return flow path for causing the valve body to open the suction flow path, and interposed between the return flow paths, wherein the one end and the other end are separately large. The switching means for switching between the state 1 for communicating with the space in the atmospheric pressure state and the state 2 for communicating both ends of the return flow path and blocking the outside, and the pressure of the discharge flow path are detected, and the detected pressure Pressure detection that outputs a signal indicating the pressure or a signal indicating the differential pressure between this pressure and the set pressure And when the pressure during operation of the compressor body exceeds a preset allowable upper limit pressure based on the signal from the stage and the pressure detection means, the switching means is set to the state 1 and the pressure is A control means for setting the switching means to the state 2 when the preset allowable lower limit pressure is exceeded, and for setting the switching means to the state 1 when the compressor body is stopped; did.

  In the second aspect of the invention, in addition to the structure of the first aspect of the invention, a bypass flow path is provided that connects the primary side and the secondary side of the valve body in the suction flow path.

  According to a third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, a suction filter provided in the suction passage on the primary side of the intake control valve, and in the state 1 to the atmosphere via the suction filter A configuration is provided in which a portion of the suction flow path between the suction filter and the compressor main body communicating with each other is provided with a purge flow path for communicating the one end and the other end via the switching valve.

  According to a fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the portion of the suction passage that communicates the one end and the other end via the switching valve with the purge passage is provided on the valve body in the suction passage. It was set as the structure which is a secondary side.

  According to a fifth aspect of the invention, in addition to the configuration of the third aspect of the invention, a portion of the suction flow path that connects the one end and the other end via the switching valve by the purge flow path is provided on the valve body in the suction flow path. The configuration is the primary side.

  According to the air compressor of the first aspect of the present invention, the intake adjustment valve can be opened and closed and the air can be discharged from the discharge flow path only by the switching operation of the single switching means, the structure is simplified, the size is reduced, and the number of parts is increased. Reduction, maintenance burden reduction, and the like.

  According to the air compressor of the second invention, in addition to the effect of the first invention, the minimum necessary amount of air from the compressor body is ensured at the time of startup, and the transition from the state 1 to the state 2 is performed. It has the effect of being promoted.

  According to the air compressor concerning the 3rd and 4th invention, in addition to the effect by the 1st or 2nd invention, it can reduce the aeration sound which leaks out of the machine at the time of the aeration from the discharge channel. It is possible to produce an effect that a silencer for suppressing this air release sound becomes unnecessary.

  According to the air compressor of the fifth aspect of the invention, in addition to the effects of the first or second aspect of the invention, it is possible to reduce the aeration sound that leaks out of the apparatus when releasing air from the discharge flow path. The silencer for suppressing the air release sound is not necessary, and the drain deposition amount can be reduced as compared with the case of the fourth invention.

Next, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an air compressor 1A according to a first embodiment of the present invention. The air compressor 1A includes a suction filter 13 and an intake adjustment valve 14 in a suction flow path 12 of the compressor body 11, and a discharge. The oil separation / recovery device 16, the pressure-retaining check valve 17 and the pressure detection means 18 are connected to the flow path 15 from the bottom of the oil separation / recovery device 16 to the oil supply location such as the rotor chamber, bearing / shaft seal portion, etc. in the compressor body 11. An oil filter 20, a three-way switching valve 21, and an oil cooler 22 are provided in the oil flow path 19 that communicates.

  The compressor body 11 has a pair of male and female screw rotors 31 meshing with each other, and the suction flow path 12 is connected to a suction port 32 formed on one side of the screw rotor 31 and the discharge flow is supplied to a discharge port 33 formed on the other side. A path 15 is connected.

  The intake adjustment valve 14 includes a casing 35, a valve body 36, a piston 38 coupled to the valve body 36 via a piston rod 37 so as to be integrally operable, and a spring 39. The casing 35 forms a portion of the suction flow path 12 that allows the suction filter 13 and the suction port 32 to communicate with each other, and a flow path space 41 that is opened and closed by a valve body 36, and the flow path space 41 is partitioned by a partition wall 42. Thus, a piston chamber 43 accommodating the piston 38 and the spring 39 is formed, and the piston rod 37 penetrates the partition wall 42. The spring 39 is interposed between the piston 38 and the partition wall 42, and always exerts a force in a direction away from the partition wall 42 with respect to the piston 38, that is, in a direction of closing the suction flow path 12 with respect to the valve body 36 via the piston rod 37. Is acting. Therefore, when the force that overcomes the spring force does not act on the pressure receiving surface of the piston 38 opposite to the piston rod 37, the intake adjustment valve 14 is closed (FIG. 1). On the other hand, when a force that overcomes the spring force acts on the pressure receiving surface, the intake adjustment valve 14 is opened (FIG. 2). In addition, a bypass channel 44 having one end communicating with the primary side of the valve body 36 in the suction channel 12 and the other end communicating with the secondary side of the valve body 36 is provided. The throttle means 45 is interposed, and the suction filter 13 and the suction port 32 are not completely disconnected.

  The oil separation / recovery unit 16 has an oil separation element 51 at the upper part, and the lower part of the oil separation / recovery unit 16 serves as an oil reservoir part 52. Pressurizing space 43a that is isolated from the portion of the discharge flow path 15 in which the detecting means 18 is interposed and the space that does not include the piston rod 37 and the spring 39 in the piston chamber 43 via the four-way switching valve 53, that is, the valve body 36. And the oil passage 19 extends from the oil reservoir 52. The four-way switching valve 53 has a P port that communicates with the oil separation element 51 in the oil separator / collector 16, a B port that communicates with the atmosphere, an EA port, and an A port that communicates with the piston chamber. Either the EA port and the A port communicate with each other (FIG. 3), or the P and A ports communicate with each other, and either the EA port or the B port is closed (FIG. 4) One state is entered. The four-way switching valve 53 is controlled as will be described later by the control unit 55 to which a pressure signal is input from the pressure detecting means 18 so as to be in any of these states. The B port is connected with a purging passage 57 having an end opened to the atmosphere, for example, with a throttle means 56 such as an orifice, and the EA port has a purge having an end opened to the atmosphere. A flow path 58 is connected. The oil passage 19 has a three-way valve X port, Y port, and Z port. The X port communicates with the oil reservoir 52 through the oil filter 20, and the Y port directly communicates with the oil supply point. In addition, an oil cooling bypass flow path 19a in which an oil cooler 22 that joins the oil flow path 19 extending from the Y port to the oil supply location is connected. When the oil temperature is lower than the set temperature, the X port and the Y port communicate with each other, the Z port is closed, and the oil is supplied to the oil supply point without being cooled. When exceeding, each of the X port and the Z port communicates, the Y port is closed, and the oil is cooled by the oil cooler 19 and supplied to the oil supply point.

Next, the operation of the pattern 1 of the air compressor 1A having the above configuration will be described.
Before the start of the air compressor 1A, as shown in FIG. 3, the four-way switching valve 53 is in a state where the P and B ports communicate with each other and the EA port and A port communicate with each other. The path 15 and the pressurizing space 4a are in a state 1 that communicates with the atmosphere separately. Accordingly, the valve element 36 in the intake adjustment valve 14 is moved in the closing direction by the spring 39, the suction flow path 12 is closed, and the discharge flow path 15 and the oil separator / recovery unit 16 are in an atmospheric pressure state.

  At the same time when the air compressor 1A is started and the compressor main body 11 starts to operate, the control unit 55 causes the four-way switching valve 53 to communicate with each of the P and A ports, and closes both the EA port and the B port. In this state, the discharge flow path 15 and the pressurizing space 43a communicate with each other and the state 2 is blocked from the outside. Accordingly, the compressed air is introduced into the pressurized space 43a as indicated by the solid arrow I in FIG. However, the discharge pressure in the discharge flow path 15 is low for a while after the operation of the compressor body 11 starts, and the pressure in the pressurizing space 43a does not rise until the spring force is overcome, and the valve body 36 changes from the state 1. Instead, the intake control valve 14 continues to be in a transient operation state with the intake valve 14 closed. Instead, since the intake air from the suction flow path 12 to the compressor body 11 is made via the bypass flow path 44 under this transient operation state, the discharge pressure gradually increases.

  When the discharge pressure rises and the pressure in the pressurizing space 43a rises to overcome the spring force, the piston 38 is actuated, and the valve body 36 is also actuated to open the intake adjustment valve 14. As a result, sufficient intake air from the suction flow path 12 to the compressor main body 11 is made, the discharge pressure rapidly rises to reach a desired range, and the air compressor 1A shifts from the transient operation state to the load operation state. .

  After that, when the discharge pressure further rises and this discharge pressure exceeds a preset allowable upper limit pressure PH, the control unit 55 to which a pressure signal from the pressure detection means 18 for detecting the discharge pressure is input is used. Based on the signal, the four-way switching valve 53 is controlled and switched to the state 1, and the air compressor 1A shifts to the unload operation state. As a result, the discharge flow path 15 and the oil separator / collector 16 communicate with the atmosphere via the P port, the B port, and the purge flow path 57, and the pressurized space 43a passes through the A port, the EA port, and the purge flow path 58. Thus, the discharge passage 15 is depressurized, and the pressurized space 43a becomes atmospheric pressure. Accordingly, in FIG. 1, the compressed air flows as indicated by the broken line arrow II, and the intake adjustment valve 14 is closed. In this case, the sudden pressure reduction in the oil separator / collector 16 generates a foaming phenomenon from the oil reservoir 52. As a result, a large amount of oil adheres to the oil separation element 51, and the oil is separated from the compressed air. In order to cause a reduction in efficiency, it is desirable to provide a throttling means 56 in the purge flow path 57 to prevent sudden pressure reduction in the oil separation and recovery unit 16 as shown in FIG. A silencer may be provided at the opening ends of the purge flow paths 57 and 58 in order to suppress noise due to the discharge of compressed air from the purge flow paths 57 and 58. The discharge flow path 15 and the oil separator / collector 16 communicate with the atmosphere, and so-called purge is performed, so that the load acting on the compressor body 11 is reduced, and the required power of the compressor body 11 is reduced, that is, unloading. Improvement of characteristics is expected. Further, the pressure in the oil separator / recovery unit 16 in the unload operation state depends on the correlation between the flow path diameter of the throttle means 45 in the bypass flow path 44 and the flow path diameter of the throttle means 56 in the purge flow path 57. The pressure in the oil separator / recovery unit 16 in the unload operation state can be maintained within a desired range by appropriately setting both the channel diameters.

  When the unload operation state continues and the discharge pressure decreases and falls below the preset allowable lower limit pressure PL, the four-way switching valve 53 is controlled by the control unit 55 based on the pressure signal from the pressure detection means 18. Controlled and switched to state 2, the air compressor 1A again shifts to the load operation state.

  As described above, in the air compressor 1A, the discharge pressure is between the allowable lower limit pressure PL and the allowable upper limit pressure PH by the switching control of the load operation state and the unload operation state via the four-way switching valve 53 by the control unit 55. Maintained within the range. That is, during the operation of the air compressor 1A, the discharge pressure rises and falls between the allowable lower limit pressure PL and the allowable upper limit pressure PH.

  When stopping the operation of the air compressor 1A, the power supply source and the compressor main body 11 are disconnected from each other, and the four-way switching valve 53 is set to the state 1 by the control unit 55, which is the same as in the unload operation state. It is kept in the state of. However, as a result of the operation stop of the air compressor 1A, even if the pressure in the discharge flow path 15 drops and reaches the allowable lower limit pressure PL, no transition to the load operation state is made.

Next, the operation of the pattern 2 of the air compressor 1A will be described.
The case of pattern 2 is almost the same as the case of pattern 1 described above, and only the transitional operation state and the transition from the transient operation state to the load operation state will be described.

  While the air compressor 1A is activated and the compressor main body 11 starts to operate, the four-way switching valve 53 is maintained in the state 1 in which the P and B ports are in communication and the EA port and A port are in communication. A drastic transient operating condition continues. Therefore, intake of the compressor body 11 is performed only through the bypass flow path 44.

  When the discharge pressure rises due to the intake air from the bypass passage 44 and exceeds the allowable lower limit pressure PL, the four-way switching valve 53 is connected to the P and A ports by the control unit 55 based on the pressure signal from the pressure detecting means 18. And the EA port and the B port are closed, the discharge passage 15 and the pressurizing space 43a are in communication with each other, and the state 2 is shut off from the outside. To shift to the load operation state.

  FIG. 5 (horizontal axis: time, vertical axis: internal pressure of the oil separation / recovery unit 16) shows a tendency that the internal pressure of the oil separation / recovery unit 16 of the air compressor 1A changes in the case of the patterns 1 and 2 described above. Is. In FIG. 5, I is a stop state, II is a transient operation state, III is a load operation state, IV is an unload operation state, V is a transition state from an unload operation state to a stop state, and a load operation state. During the unload operation state, the internal pressure is maintained within a range between the allowable lower limit pressure PL and the allowable upper limit pressure PH.

  In FIG. 5, the slope of the line segment in the transient operation state II is not necessarily the same in pattern 1 and pattern 2, but does not change in terms of a gradual increase tendency.

  The intake adjustment valve 14 has a structure using a piston 38 to operate the valve body 36. However, as shown in FIG. 6, an intake adjustment valve 14a having a structure using a diaphragm 61 instead of the piston 38 is used. There may be. In FIG. 6, parts common to FIGS. 1 and 2 are given the same reference numerals, and the central portion of the diaphragm 61 operates up and down in the drawing similarly to the piston 38. The pressure detecting means 18 may be either a pressure sensor that outputs a pressure signal corresponding to the detected pressure, or a pressure switch that outputs a pressure signal corresponding to a differential pressure between the detected pressure and a preset pressure. .

  FIG. 7 shows an air compressor 1B according to the second embodiment of the present invention, and portions common to the air compressor 1A described above are denoted by the same reference numerals and description thereof is omitted.

  In the air compressor 1B, instead of the purge flow paths 57 and 58 described above, purge flow paths 57a and 58a that merge with the portion of the suction flow path 12 between the intake adjustment valve 14 and the compressor body 11 are provided. Yes.

  And by such a structure, the compressed air which escapes from the discharge flow path 15 and the pressurization space 43a is guide | induced to the part of the said suction flow path 12, and the noise which leaks outside is suppressed, and a silencer is omitted. Is possible.

  FIG. 8 shows an air compressor 1C according to the third embodiment of the present invention, and portions common to the air compressor 1A described above are denoted by the same reference numerals and description thereof is omitted.

  In the air compressor 1C, instead of the purge flow paths 57 and 58 described above, purge flow paths 57b and 58b that join the suction flow path 12 between the suction filter 13 and the intake adjustment valve 14 are provided. .

  And by such a structure, the compressed air which escapes from the discharge flow path 15 and the pressurization space 43a is guide | induced to the part of the said suction flow path 12, and the noise which leaks outside is suppressed, and a silencer is omitted. Is possible.

  Although the oil-cooled type has been described above, the present invention is not limited to this, and may be a water-circulated type. In this case, the oil including the oil separation and recovery unit 16, the oil filter 20, and the oil cooler 22 is used. The flow path 19 is omitted, and instead, a flow path is provided for circulating water.

  The present invention is not limited to a screw type air compressor, and may be a positive displacement air compressor.

It is a figure showing the whole air compressor composition concerning a 1st embodiment of the present invention. It is a figure which shows the open state of the intake regulating valve in the air compressor shown in FIG. It is a figure which shows the four-way switching valve in the state 1 of the air compressor shown in FIG. It is a figure which shows the four-way switching valve in the state 2 of the air compressor shown in FIG. It is a figure which shows the transition tendency of the internal pressure of the oil separation recovery device in the air compressor shown in FIG. It is a figure which shows the intake regulating valve of another form in the air compressor shown in FIG. It is a figure which shows the whole structure of the air compressor which concerns on 2nd Embodiment of this invention. It is a figure which shows the whole structure of the air compressor which concerns on 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A Air compressor 11 Compressor main body 12 Suction flow path 13 Suction filter 14, 14a Intake adjustment valve 15 Discharge flow path 16 Oil separation recovery device 17 Holding pressure check valve 18 Pressure detection means 19 Oil flow path 20 Oil filter 21 Three-way switching Valve 22 Oil cooler 31 Screw rotor 32 Suction port 33 Discharge port 35 Casing 36 Valve body 37 Piston rod 38 Piston 39 Spring 41 Channel space 42 Partition wall 43 Piston chamber 43a Pressurizing space 44 Bypass channel 45 Throttle means 51 Oil separation element 52 Oil reservoir 53 Four-way switching valve 54 Return flow path 55 Control section 56 Throttle means 57, 58 Purge flow path 61 Diaphragm A, B, EA, P Port X, Y, Z port

Claims (5)

The compressor body,
An intake adjustment valve that is provided in the suction flow path so as to be openable and closable, and has a built-in valve element that is constantly urged by a spring force in a direction to close the suction flow path;
One end communicates with the discharge flow path, and the other end communicates with the space inside the intake regulating valve that is cut off from the valve body. The discharge air from the compressor body is guided to the space, and the valve body An air compressor having a return flow path for generating a force to open the flow path,
Switching between a state 1 that is provided in the return flow path and in which the one end and the other end are separately communicated with a space in an atmospheric pressure state, and a state 2 in which both ends of the return flow path are communicated and shut off from the outside. Switching means to perform,
Pressure detecting means for detecting the pressure of the discharge flow path and outputting a signal indicating the detected pressure or a signal indicating a differential pressure between the pressure and the set pressure;
Based on the signal from the pressure detection means, when the pressure during the operation of the compressor body exceeds a preset allowable upper limit pressure, the switching means is set to the state 1 and the pressure is preset. And a control means for setting the switching means to the state 2 when the compressor body is stopped and a control means for setting the switching means to the state 1 when the compressor body is stopped. air compressor.   The air compressor according to claim 1, further comprising a bypass channel that communicates a primary side and a secondary side of the valve body in the suction channel. A suction filter provided in the suction flow path on the primary side of the intake control valve;
In the state 1, the purge flow is made such that the one end and the other end communicate with each other through the switching valve to the portion of the suction flow path between the suction filter communicating with the atmosphere via the suction filter and the compressor body. The air compressor according to claim 1, further comprising a passage.   The portion of the suction flow path that communicates the one end and the other end with the purge flow path via the switching valve is a secondary side of the valve body in the suction flow path. The air compressor described. The portion of the suction flow path that communicates the one end and the other end via the switching valve with the purge flow path is a primary side of the valve body in the suction flow path. Air compressor.

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