Engine-driven compressor and operation control method thereof

Abstract

The present application provides an engine-driven compressor and a method for controlling the operation thereof, which can reduce the load at an early stage at the time of starting and can avoid the pressure rise at the time of overshoot occurrence at an early stage. A pressure adjusting valve provided by an intake adjusting device of a compressor main body, a first bypass flow path and a second bypass flow path which communicate a receiving container with a closed valve pressure chamber of the pressure adjusting valve, and a gas discharge flow path which discharges the closed valve pressure chamber, and a first electromagnetic valve of NO type provided in the first bypass flow path and a second electromagnetic valve of NC type provided in the second bypass flow path are provided, and a starting operation in which the first electromagnetic valve is not energized (open) is performed until a predetermined starting operation release condition is satisfied to start the engine. In a normal operation in which the intake adjusting device performs intake control, when the pressure in the receiving container becomes above an overshoot pressure, the second electromagnetic valve is energized (open) in a state in which the first electromagnetic valve is maintained in an energized (closed) state to perform an overshoot avoidance operation.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for controlling the operation of an engine-driven compressor and an engine-driven compressor that executes the method for controlling the operation, and more particularly to a method for controlling the operation of an engine-driven compressor such as one capable of reducing the starting load, avoiding overshoot, and the like, and an engine-driven compressor that executes the method for controlling the operation. BACKGROUND

[0002] Engine-driven compressors provided with an engine such as a diesel engine as a driving source for a compressor main body are widely used in outdoor work such as civil engineering sites, construction sites, and the like where it is difficult to secure a power source.

[0003] As one example of such an engine-driven compressor, the configuration example of an engine-driven compressor 300 provided with an oil-cooled compressor main body 340 that compresses both compressed gas and lubricating oil and discharges them as a gas-liquid mixed fluid is shown in Figure 8

[0004] The engine-driven compressor 300 is configured to be provided with, in addition to the aforementioned compressor main body 340 and engine 350, a reception container 360 for separating the lubricating oil discharged together with the compressed gas by the compressor main body 340, and the compressed gas after the lubricating oil is separated in the reception container 360 further removes oil through an oil separator 366 and then is supplied to a consumption side connected to an air working machine or the like not shown. Also, the engine-driven compressor 300 is provided with an oil supply flow path 364 that supplies the lubricating oil recovered into the reception container 360 to the compressor main body 340 via an oil cooler 363 and an oil filter 367.

[0005] In such an engine-driven compressor 300, in order to be able to supply the consumption side with compressed gas of a stable pressure, a suction adjusting device 310 is provided that adjusts the amount of suction of the compressor main body 340 according to the discharge side pressure of the compressor main body 340, that is, the pressure in the reception container 360 under the illustrated configuration.

[0006] In Figure 8 ​In the engine-driven compressor 300 shown, as the suction adjusting device 310, a suction adjusting valve 311 that opens and closes a suction port 341 of the compressor main body 340 and a unloading regulator 316 that controls the opening and closing of the suction adjusting valve 311 are provided, the unloading regulator 316 is communicated with a receiving container 360 by a flow path 312, and the compressed gas in the receiving container 360 is introduced into the unloading regulator 316 as a working pressure for closing the suction adjusting valve 311, and a pressure adjusting valve 313 that opens the flow path 312 when the pressure in the receiving container 360 is equal to or higher than a predetermined rated pressure is provided.

[0007] In addition, Figure 8 The flow path 314 in the drawing is a discharge flow path configured to discharge the compressed gas in the pressure chamber of the unloading regulator 316 through a throttle portion 315 when the pressure adjusting valve 313 closes the flow path 312 and stops the introduction of the compressed gas into the unloading regulator 316, and the unloading regulator 316 is returned to the fully open position by the force of a return spring (not shown).

[0008] By providing the suction adjusting device 310 thus configured, the suction adjustment of the compressor main body 340 is performed in the following manner. If the pressure in the receiving container 360 becomes equal to or higher than the rated pressure, the introduction of the compressed gas in the receiving container 360 into the unloading regulator 316 is started, the suction adjusting valve 311 throttles the suction port 341 of the compressor main body 340 or closes the suction port 341, and if the pressure in the receiving container 360 decreases to be lower than the rated pressure, the suction adjusting valve 311 opens the suction port 341 of the compressor main body 340, thereby bringing the pressure in the receiving container 360 close to the rated pressure.

[0009] In the engine-driven compressor 300 thus configured, the torque of the engine 350 that is the driving source of the compressor main body 340 is small in a low rotation speed range, and if a load is applied at the time of start, the engine 350 is likely to stop (stall).

[0010] On the other hand, in the engine-driven compressor 300, the load of the engine 350, that is, the compressor main body 340 and the engine 350 are directly linked, and the engine 350 receives a load accompanying the rotation of the compressor main body 340 from the start, and therefore, if the load received by the engine 350 from the compressor main body 340 at the time of start can be reduced, the engine 350 can be started smoothly.

[0011] With the configuration of the engine-driven compressor 300, in order to reduce the load applied to the engine 350 at the time of start, a start load reduction device 320 shown in the following patent document 1 is provided. Figure 8 The configuration of the start load reduction device 320 is shown by the reference numeral 320 in the patent document.

[0012] The start load reduction device 320 is configured by a bypass passage 321 that communicates the unloading regulator 316 with the receiving container 360 via the bypass pressure adjusting valve 313, and a bypass valve 325 that opens and closes the bypass passage 321, and is configured so that, at the start, the bypass valve 325 is operated to open the bypass passage 321, thereby enabling the unloading regulator 316 to communicate with the receiving container 360 not via the pressure adjusting valve 313 but directly with the receiving container 360.

[0013] As a result, if the compressor main body 340 starts to rotate by the start of the engine 350, thereby the pressure in the receiving container 360 rises, the unloading regulator 316 operates to close the suction adjusting valve 311, the compressor main body 340 shifts to no-load operation, thereby enabling the load applied to the engine 350 at the start of the start to be reduced.

[0014] Then, after the operation state of the engine 350 is stabilized, the bypass valve 325 provided to the start load reduction device 320 is operated to close the bypass passage 321, the pressure adjusting valve 313 returns to the normal operation of opening and closing the passage 312 according to the pressure in the receiving container 360, thereby enabling the known suction adjustment to be performed.

[0015] In addition, in the above-described patent document 1, a configuration is disclosed in which a manual on-off valve is provided as the aforementioned bypass valve 325, but an engine-driven compressor is also proposed in which the manual on-off valve is changed to a solenoid valve, and the opening and closing operation of the bypass valve 325 is electrically controlled based on the detected operation state of the engine (see patent document 2).

[0016] Further, in the configuration in which the bypass valve 325 is configured by a solenoid valve and the opening and closing thereof is electrically controlled, the aforementioned start load reduction device 320 also has a function other than the function of reducing the start load, as one example, in Figure 9 the example shown in the drawing, in the following aspects is the same as Figure 8 the example of (A) of the foregoing, that is, when the engine is started, the bypass valve 325 is opened and the suction adjusting valve 311 is closed to reduce the start load Figure 9 (A) of the foregoing), and if the engine is stably operated, the bypass valve 325 is closed, and the pressure adjusting valve 313 is normally operated to open and close the passage 312 according to the pressure in the receiving container 360 Figure 9 (B) of the foregoing). However, when so-called "overshoot" occurs in which the pressure in the receiving container 360 excessively rises with respect to the aforementioned rated pressure because the closing operation of the suction adjusting valve 311 is not performed in time by the pressure adjusting valve 313, the function as a safety device is also possessed (see Figure 9specifically, the bypass valve 325 is opened and the suction adjusting valve 311 is closed, and the compressed gas in the receiving container 360 is discharged via the bypass flow path 321 and the purge flow path 314, so that the pressure in the receiving container 360 is reduced to avoid overshoot. Also, the bypass valve 325 can also be used as a purge mechanism Figure 9 (A), the bypass valve 325 is opened when the engine-driven compressor 300 is stopped, so that the compressed gas in the receiving container 360 is discharged via the bypass flow path 321 and the purge flow path 314.

[0017] Patent Document 1: Japanese Patent Application Publication No. 2002-168177

[0018] Patent Document 2: Japanese Patent Application Publication No. 2017-115598

[0019] As the operation form of the electromagnetic valve, there are a normally open type (NO type) electromagnetic valve in which a valve body is in an open valve state by being separated from a valve seat by the force of a return spring in a non-energized state, and is seated on the valve seat by energization of a solenoid to close the valve, and a normally closed type (NC type) electromagnetic valve in which a valve body is in a closed valve state by being seated on a valve seat by the force of a return spring in a non-energized state, and is separated from the valve seat by energization of a solenoid to open the valve.

[0020] According to such an electromagnetic valve, the force generated by the solenoid at the time of energization is used to drive the valve body to which the force of the return spring is applied in the non-energized state, and the valve body is caused to perform opening and closing operations, so that a larger driving force of the valve body can be obtained at the time of energization of the solenoid to drive the valve body.

[0021] In addition, the difference between the primary side pressure and the secondary side pressure of the electromagnetic valve is larger at the time of closing than at the time of opening, and in an electromagnetic valve in which the valve body is normally seated on the valve seat from the primary side, a force is generated in the valve body in the direction in which it is pressed against the valve seat at the time of closing due to this pressure difference, so that a larger driving force is required to move the valve body in order to open the valve in the closed state than to close the valve in the open state.

[0022] As a result, the normally closed type (NC type) electromagnetic valve in which the opening operation requiring a large driving force is performed by the solenoid has a larger maximum working pressure difference (the maximum value of the difference between the primary side pressure and the secondary side pressure at which the electromagnetic valve can be operated) than the normally open type (NO type) electromagnetic valve.

[0023] In addition, as described with reference to Figure 9As explained in (A), when the bypass valve 325 is configured with a solenoid valve, and the bypass valve 325 and the bypass flow path 321 function not only as a starting load reduction device 320, but also as a purging mechanism for discharging compressed gas from the receiving container 360 when the engine-driven compressor 300 stops, the bypass valve 325 needs to be a normally open (NO type) solenoid valve so that it opens and purges when the main power supply to the engine-driven compressor 300 is cut off.

[0024] Thus, when the starting load reduction device 320 has the function of purging compressed gas in the receiving container 360 when the engine-driven compressor 300 stops, the bypass valve 325 must be a normally open (NO) type solenoid valve. However, as mentioned above, the normally open (NO) type solenoid valve has a low maximum operating pressure difference. Therefore, when an overshoot occurs where the pressure in the receiving container 360 exceeds the rated pressure and rises excessively, that is, when the difference between the primary and secondary pressures of the bypass valve 325 is increasing, the bypass valve 325 cannot be opened even if the power is stopped.

[0025] Therefore, when the bypass valve 325 is a normally open (NO) type solenoid valve, the starting load reduction device 320 cannot be directly used as a reference. Figure 9 (C) describes overshoot avoidance operation, which requires... Figure 9 As shown, a pressure reducing valve 326 is provided on the primary side of the bypass valve 325 to reduce the pressure difference between the primary and secondary sides of the bypass valve 325 when overshoot occurs to below the maximum working pressure difference of the normally open (NO) type solenoid valve, i.e., the bypass valve 325.

[0026] Such pressure reducing valves, such as the 326 specification, also have operating pressure and operating temperature ranges. High-pressure pressure reducing valves are hard to find and expensive. Summary of the Invention

[0027] Therefore, the present invention is to overcome the reference Figure 9 This invention addresses the shortcomings of engine-driven compressors and aims to provide an operation control method for an engine-driven compressor and an engine-driven compressor that executes this operation control method. This method enables the intake regulating valve to close early after startup, reducing the load applied to the engine immediately after startup. Furthermore, by not installing a pressure reducing valve, it enables early no-load operation and discharge of compressed gas from the receiving container in the event of overshoot, thereby minimizing the pressure rise in the receiving container during overshoot.

[0028] Hereinafter, the reference numerals used in the detailed description are described in the summary. The reference numerals are used to make the correspondence between the description of the claims and the description of the detailed description clear, and of course are not used to explain the technical scope of the present application.

[0029] To achieve the above object, the operation control method of an engine-driven compressor according to the present application is characterized in that the engine-driven compressor includes an engine (not shown), a compressor main body 40 driven by the engine, and a suction adjustment device 10 that controls suction to the compressor main body 40, the suction adjustment device 10 including: a suction adjustment valve 11 that opens and closes a suction port 41 of the compressor main body 40; a control flow path 12 that communicates between a closed valve pressure chamber 113 of the suction adjustment valve 11 and the discharge side (in the illustrated embodiment, a receiving container 60) of the compressor main body 40; and a pressure adjustment valve 13 that opens the control flow path 12 when the discharge side pressure of the compressor main body 40 is equal to or higher than a predetermined rated pressure, and closes the control flow path 12 when the discharge side pressure of the compressor main body 40 is lower than the rated pressure, the engine-driven compressor 1 is provided with: a first bypass flow path 21 and a second bypass flow path 22 that bypass the pressure adjustment valve 13, and communicate between the discharge side (receiving container 60) of the compressor main body 40 and the closed valve pressure chamber 113 of the suction adjustment valve 11, respectively; a bleed flow path 14 that throttles and bleeds compressed gas in the closed valve pressure chamber 113 of the suction adjustment valve 11; a first electromagnetic valve 23 that opens and closes the first bypass flow path 21; and a second electromagnetic valve 24 that opens and closes the second bypass flow path 22, and the first electromagnetic valve 23 is set as a normally open (NO) type electromagnetic valve, and the second electromagnetic valve 24 is set as a normally closed (NC) type electromagnetic valve having a maximum pressure difference that is higher than the maximum pressure difference that can be generated between the primary side and the secondary side of the second electromagnetic valve 24, a start-up operation in which the first electromagnetic valve 23 is in a non-energized (open) state is performed, after the engine is started, when a predetermined start-up operation release condition is satisfied, the first electromagnetic valve 23 is energized (closed) and the second electromagnetic valve 24 is de-energized (closed) to stop the start-up operation, and transition to a normal operation in which suction control is performed by the suction adjustment device 10, and in the normal operation, when the pressure on the discharge side (in the receiving container 60) of the compressor main body 40 becomes equal to or higher than a predetermined overshoot pressure (P1) with respect to the rated pressure, the second electromagnetic valve 24 is energized (open) in a state in which the first electromagnetic valve 23 is maintained in an energized (closed) state, and transition to an overshoot avoidance operation in which the suction adjustment valve 11 is closed is performed.

[0030] Preferably, in the above-described operation control method, configured to: in the overshoot avoidance operation, when the pressure on the discharge side (in the receiving container 60) of the compressor main body is a predetermined low pressure with respect to the overshoot pressure (P1) and becomes lower than the recovery pressure (P2) that is higher than the rated pressure, the second electromagnetic valve is de-energized (closed) to end the overshoot avoidance operation and return to the normal operation.

[0031] Preferably, in the start-up operation, the second electromagnetic valve 24 is energized (opened).

[0032] Further, preferably, configured such that the engine-driven compressor 1 is provided with a purge switch 71, and by turning on the purge switch 71, a purge operation is started in which the first electromagnetic valve 23 is de-energized (thereby, in the condition that "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23", the first electromagnetic valve 23 is opened) and the second electromagnetic valve 24 is energized (opened), by turning off the purge switch 71, the first electromagnetic valve 23 is energized (closed) and the second electromagnetic valve 24 is de-energized (closed) to end the purge operation and return to the normal operation.

[0033] In addition, preferably, configured such that by turning off the main switch 70, a cooling operation is performed in which the first electromagnetic valve 23 is de-energized (thereby, in the condition that "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23", the first electromagnetic valve 23 is opened) and the second electromagnetic valve 24 is energized (opened) to continue the operation of the engine, when a predetermined end condition (for example, any one of the conditions that a predetermined time has elapsed, the engine cooling water temperature or the discharge temperature of the compressor main body 40 has decreased to a predetermined temperature or less, or a combination of a plurality of conditions) is satisfied, the second electromagnetic valve 24 is de-energized (closed), and the engine is stopped to end the cooling operation.

[0034] Further, the engine-driven compressor 1 of the present application is characterized by including an engine (not shown), a compressor main body 40 driven by the engine, and a suction adjustment device 10 that controls suction to the compressor main body 40, the suction adjustment device 10 including: a suction adjustment valve 11 that opens and closes a suction port 41 of the compressor main body 40; a control flow path 12 that communicates between a closed-valve pressure chamber 113 of the suction adjustment valve 11 and the discharge side (in the illustrated embodiment, a receiving container 60) of the compressor main body 40; and a pressure adjustment valve 13 that opens the control flow path 12 when the discharge side pressure of the compressor main body 40 is a predetermined rated pressure or more and closes the control flow path 12 when the discharge side pressure of the compressor main body 40 is less than the rated pressure, the engine-driven compressor 1 being provided with: a first bypass flow path 21 and a second bypass flow path 22 that bypass the pressure adjustment valve 13 and communicate between the discharge side (receiving container 60) of the compressor main body 40 and the closed-valve pressure chamber 113 of the suction adjustment valve 11, respectively; a bleed flow path 14 that throttles and bleeds compressed gas in the closed-valve pressure chamber 113 of the suction adjustment valve 11; a first electromagnetic valve 23 that opens and closes the first bypass flow path 21; a second electromagnetic valve 24 that opens and closes the second bypass flow path 22; and a controller 30 that controls energization of the first electromagnetic valve 23 and the second electromagnetic valve 24 to switch operating states, the first electromagnetic valve 23 being configured as a normally open (NO) type electromagnetic valve, and the second electromagnetic valve 24 being configured as a normally closed (NC) type electromagnetic valve having a maximum pressure difference that is higher than the maximum pressure difference that can be generated between the primary side and the secondary side of the second electromagnetic valve 24, the controller 30 being configured to: perform a start-up operation in which the engine is started in a state in which the first electromagnetic valve 23 is de-energized (open), stop the start-up operation and shift to a normal operation in which suction is controlled by the suction adjustment device 10 when a predetermined start-up operation release condition is satisfied after the engine is started and make the second electromagnetic valve 24 energized (open) in a state in which the first electromagnetic valve 23 is maintained in an energized (closed) state when the pressure on the discharge side (in the receiving container 60) of the compressor main body 40 becomes a predetermined overshoot pressure (P1) or more with respect to the rated pressure in the normal operation to perform an overshoot avoidance operation in which the no-load operation in which the suction adjustment valve 11 is closed is shifted to.

[0035] In the engine-driven compressor 1 of the above-described configuration, it is possible to configure such that, in the overshoot avoidance operation, when the pressure on the discharge side (inside the receiving container 60) of the compressor main body 40 is a predetermined low pressure with respect to the overshoot pressure (P1) and becomes a recovery pressure (P2) or less that is higher than the rated pressure, the controller 30 deenergizes (closes) the second electromagnetic valve 24 to end the overshoot avoidance operation and returns to the normal operation.

[0036] Further, it is preferable to configure such that the controller 30 energizes (opens) the second electromagnetic valve 24 at the time of the start-up operation.

[0037] Further, it is preferable to configure such that, in the configuration in which the engine-driven compressor 1 is provided with a purge switch 71, the controller 30 starts a purge operation in which the first electromagnetic valve 23 is deenergized (thereby, the first electromagnetic valve 23 is opened in the condition of "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23") and the second electromagnetic valve 24 is energized (opened) by the conduction of the purge switch 71, ends the purge operation by the disconnection of the purge switch 71 in which the first electromagnetic valve 23 is energized (closed) and the second electromagnetic valve 24 is deenergized (closed), and returns to the normal operation.

[0038] Further, it is preferable to configure such that the controller 30 performs a cooling operation in which the first electromagnetic valve 23 is deenergized (thereby, the first electromagnetic valve 23 is opened in the condition of "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23") and the second electromagnetic valve 24 is energized (opened) by the disconnection of the main switch 70, deenergizes (closes) the second electromagnetic valve 24 and stops the engine when a predetermined end condition (for example, any one of the conditions of elapse of a predetermined time, a decrease in the cooling water temperature of the engine or the discharge temperature of the compressor main body 40 to a predetermined temperature or less, or a combination of a plurality of conditions) is satisfied, and ends the cooling operation.

[0039] According to the configuration of the present application described above, in the engine-driven compressor 1 that executes the operation control method of the present application, the following remarkable effects can be obtained.

[0040] The first bypass passage 21 and the second bypass passage 22 bypassing the pressure adjusting valve 13 are provided, the second bypass passage 22 employs a normally closed (NC) type solenoid valve as a second solenoid valve 24 that opens and closes the second bypass passage 22, the normally closed (NC) type solenoid valve has a maximum working pressure difference that is larger than a maximum pressure difference that can be generated between a primary side and a secondary side of the second solenoid valve, and, at the time of overshoot, the suction adjusting valve 11 can be closed by the opening of the second solenoid valve 24 to shift to the overshoot avoidance operation, so that, at the time of overshoot in which the difference between the primary side pressure and the secondary side pressure of the first solenoid valve 23 can become the largest, the first solenoid valve 23 does not need to be opened, as a result, the first solenoid valve 23 provided in the first bypass passage 21 can employ a normally open (NO) type solenoid valve that has only a maximum working pressure difference that is smaller than the maximum pressure difference that can be generated between the primary side and the secondary side of the first solenoid valve 23, and, even in the case of employing such a normally open (NO) type solenoid valve, a pressure reducing valve does not need to be provided in the primary side of the first solenoid valve 23.

[0041] As a result, although the control to shift to the no-load operation is performed at the time of overshoot, if the energization to the first solenoid valve 23 is stopped at the time of engine-driven compressor 1 stop (at the time of main power supply cutoff), the first solenoid valve 23 is opened, the exhaust (purge) of the compressed gas in the receiving container 60 can be performed, so that the advantage of employing the normally open (NO) type solenoid valve described above can be enjoyed without providing an expensive pressure reducing valve.

[0042] In addition, even at the time of the overshoot avoidance operation, the discharge side pressure of the compressor main body 40 (the pressure in the receiving container 60) is introduced into the closing valve pressure chamber 113 of the suction adjusting valve 11 via the second bypass passage 22, so that if the discharge side pressure of the compressor main body 40 (the pressure in the receiving container 60) becomes the overshoot pressure PI or more and the second solenoid valve 24 is opened by the energization, the suction adjusting valve 11 is closed in a relatively short time to stop the generation of the compressed gas by the compressor main body 40, so that the further increase of the discharge side pressure of the compressor main body 40 (the pressure in the receiving container 60) at the time of overshoot can be stopped early, whereby the peak pressure (Pmax) of the receiving container 60 at the time of overshoot can be suppressed to be relatively low.

[0043] At the time of the start operation, in the case where the second solenoid valve 24 is also energized (opened) to open the second solenoid valve 24, the introduction of the working pressure from both systems into the closing valve pressure chamber 113 of the suction adjusting valve 11 is performed at the same time, and, in addition, in the case where the bore of the normally closed (NC) type second solenoid valve 24 is generally larger than the bore of the normally open (NO) type first solenoid valve 23 and has a larger flow area, the closing operation of the suction adjusting valve 11 at the time of engine start can be completed even earlier.

[0044] The engine-driven compressor 1 is provided with a purge switch 71, and by turning on the purge switch 71, the first electromagnetic valve 23 is de-energized (thereby, the first electromagnetic valve 23 is opened in the condition of "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23"), and the second electromagnetic valve 24 is energized (opened) in the configuration in which the first electromagnetic valve 23 is de-energized and the second electromagnetic valve 24 is energized, and the operator can shift to the purge operation performed while discharging the pressure of the discharge side of the compressor main body (the pressure in the receiving container 60) in the no-load operation state in which the suction adjusting valve 11 is closed by operating the purge switch 71 as needed.

[0045] In particular, the second electromagnetic valve 24 of the normally closed (NC) type has a large bore and a large flow passage area compared to the normally open (NO) type electromagnetic valve, and thus, by performing such exhaust (purge) through the second bypass passage 22, the pressure of the discharge side (inside the receiving container 60) of the compressor main body 40 can be reduced early.

[0046] Further, the engine-driven compressor 1 is configured such that, by turning off the main switch 70, the first electromagnetic valve 23 is de-energized (thereby, the first electromagnetic valve 23 is opened in the condition of "the pressure difference between the primary side and the secondary side of the first electromagnetic valve 23 ≤ the maximum working pressure difference of the first electromagnetic valve 23"), and the second electromagnetic valve 24 is energized (opened) to perform the cooling operation in which the engine continues to operate in the no-load state in which the suction adjusting valve 11 is closed, and thus, the cooling operation of the engine is performed while exhausting the compressed gas of the discharge side (inside the receiving container 60) of the compressor main body 40 in the no-load state in which the suction adjusting valve 11 is closed, and thus, the aforementioned cooling operation can be performed in a state in which the load applied to the engine is as low as possible. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a diagram illustrating the overall configuration of the engine-driven compressor of the present application.

[0048] Figure 2 is a cross-sectional view illustrating one configuration example of the suction adjusting valve.

[0049] Figure 3 is a diagram illustrating the main part of the engine-driven compressor of the present application, (A) is a diagram at the time of start-up operation, (B) is a diagram at the time of normal operation, and (C) is a diagram at the time of overshoot avoidance operation.

[0050] Figure 4 is a diagram illustrating the main part of the engine-driven compressor of the present application, (A) is a diagram at the time of purge operation and stop, and (B) is a diagram at the time of cooling operation.

[0051] Figure 5 is a functional block diagram of an engine-driven compressor of the present application.

[0052] Figure 6 is a timing chart showing the operation of each part in the start-up operation, normal operation, and overshoot avoidance operation of the engine-driven compressor of the present application.

[0053] Figure 7 is a timing chart showing the operation of each part in the purge operation and from the cooling operation to the stop of the engine-driven compressor of the present application.

[0054] Figure 8 is an explanatory diagram of a conventional engine-driven compressor provided with a start-up load reduction device (corresponding to Patent Document 1).

[0055] Figure 9 is an explanatory diagram of an engine-driven compressor in which the start-up load reduction device is provided with an overshoot avoidance function and a purge function at the time of stop, (A) is an explanatory diagram showing the operation of each part at the time of start-up operation and at the time of stop, (B) is an explanatory diagram showing the operation of each part at the time of normal operation, and (C) is an explanatory diagram showing the operation of each part at the time of overshoot occurrence.

[0056] BRIEF DESCRIPTION OF DRAWINGS

[0057] 1 engine-driven compressor

[0058] 10 suction adjusting device

[0059] 11 suction adjusting valve

[0060] 111 body (valve case)

[0061] 112 airtight chamber (cylinder)

[0062] 113 closed valve pressure-receiving chamber

[0063] 114 auxiliary pressure-receiving chamber (spring chamber)

[0064] 114a spring

[0065] 115 suction flow path

[0066] 115a valve seat

[0067] 116 valve body

[0068] 116a valve shaft

[0069] 117 sleeve

[0070] 118 end plate

[0071] 119 pressure-receiving body (piston)

[0072] 12 control flow path

[0073] 13 pressure regulating valve

[0074] 14 air release flow path

[0075] 15 throttle portion

[0076] 21 first bypass flow path

[0077] 22 second bypass flow path

[0078] 23 first solenoid valve (normally open (NO) type)

[0079] 24 second solenoid valve (normally closed (NC) type)

[0080] 25 common flow path

[0081] 26 diverging block

[0082] 27 three-way solenoid valve

[0083] 28a to 28c flow paths

[0084] 30 controller

[0085] 36 timer

[0086] 40 compressor main body

[0087] 41 suction port

[0088] 51 temperature sensor

[0089] 60 receiving container

[0090] 61 pressure regulating valve

[0091] 62 discharge flow path

[0092] 63 oil cooler

[0093] 64 oil supply flow path

[0094] 65 pressure sensor

[0095] 66 service valve

[0096] 70 main switch

[0097] 71 purge switch

[0098] 72 start switch

[0099] 300 engine-driven compressor

[0100] 310 suction adjusting device

[0101] 311 suction adjusting valve

[0102] 312 control flow path

[0103] 313 pressure adjusting valve

[0104] 314 gas discharge flow path

[0105] 315 throttle portion

[0106] 316 unloading regulator

[0107] 320 start load reduction device

[0108] 321 bypass flow path

[0109] 325 bypass valve

[0110] 326 pressure reducing valve

[0111] 340 compressor main body

[0112] 341 suction port

[0113] 350 engine

[0114] 360 receiving container

[0115] 363 oil cooler

[0116] 364 oil supply flow path

[0117] 366 oil separator

[0118] 367 oil filter DETAILED DESCRIPTION

[0119] Hereinafter, the configuration of the present application will be described with reference to the drawings.

[0120] (Overall configuration of engine-driven compressor)

[0121] Figure 1 Reference numeral 1 in FIG. 1 is an engine-driven compressor of the present application, which is provided with a compressor main body 40, an engine (not shown) that drives the compressor main body 40, and a receiving container 60 that stores compressed gas discharged from the compressor main body 40, and is configured to supply the compressed gas discharged from the compressor main body 40 to an air working machine or the like, not shown, connected to a service valve 66, after the compressed gas is stored in the receiving container 60.

[0122] In the present embodiment, the aforementioned compressor main body 40 is an oil-cooled screw compressor that co-compresses compressed gas and lubricating oil for lubrication, cooling, and sealing, configured so that the gas-liquid mixed fluid of compressed gas and lubricating oil is discharged, the compressed gas is introduced into the receiving container 60 via the discharge flow path 62, the lubricating oil can be separated in the receiving container 60, and the oil supply flow path 64 that supplies the lubricating oil recovered in the receiving container 60 to the compressor main body 40 again via the oil cooler 63 is provided.

[0123] However, the compressor main body 40 of the engine-driven compressor 1 that is the subject of the present application is not limited to such an oil-cooled compressor main body, and an oil-free compressor main body that does not require lubricating oil during compression of compressed gas can also be mounted, in which case the aforementioned receiving container 60, the oil supply flow path 64 for supplying the lubricating oil recovered in the receiving container 60 to the compressor main body 40, and the like can be omitted.

[0124] (Suction adjustment device)

[0125] The engine-driven compressor 1 configured as described above is the same as the existing engine-driven compressor described with reference to Figure 8 the aforementioned suction adjustment, if the secondary side pressure of the compressor main body 40, that is, the pressure in the receiving container 60 in the present embodiment, becomes equal to or higher than a predetermined rated pressure, the suction port 41 of the compressor main body 40 is throttled or closed, and if the pressure in the receiving container 60 is lower than the rated pressure, the suction port 41 of the compressor main body 40 is fully opened so that the pressure in the receiving container 60 approaches the predetermined rated pressure.

[0126] In addition, in the aspect in which the suction adjustment device 10 is configured by the suction adjustment valve 11, the control flow path 12, and the pressure adjustment valve 13, and the aspect in which the gas discharge flow path 14 is provided, the engine-driven compressor is the same as the engine-driven compressor described with reference to Figure 8 the aforementioned suction adjustment, if the secondary side pressure of the compressor main body 40, that is, the pressure in the receiving container 60 in the present embodiment, becomes equal to or higher than a predetermined rated pressure, the suction port 41 of the compressor main body 40 is throttled or closed, and if the pressure in the receiving container 60 is lower than the rated pressure, the suction port 41 of the compressor main body 40 is fully opened so that the pressure in the receiving container 60 approaches the predetermined rated pressure.

[0127] (Suction adjustment valve)

[0128] The aforementioned suction adjusting valve 11 constituting the suction adjusting device 10 opens and closes the suction port 41 of the compressor main body 40 as described above, and in the present embodiment, as one example, the suction adjusting valve 11 shown in FIG. 1 is used. Figure 2

[0129] The suction adjusting valve 11 shown in FIG. 1 is configured to form a suction flow path 115 through which the compressed gas passes using a space formed inside a body (valve case) 111, and to be able to occlude the suction flow path 115 by seating a valve body 116 against a valve seat 115a provided inside the suction flow path 115. Figure 2

[0130] The valve body 116 is a so-called "umbrella type valve" in which a valve shaft 116a is attached to the valve body 116 in a disc shape, and is configured to be able to move the valve body 116 between a closed valve position in which the valve body 116 is seated against the valve seat 115a, and an open valve position in which the valve body 116 is separated from the valve seat 115a, by moving the valve body 116 in and out along the axis direction of the sleeve 117 in a state in which the valve shaft 116a is inserted into the sleeve 117 formed in a cylindrical shape inside the body 111.

[0131] In order to be able to achieve such movement of the valve body 116, in the valve case 111 of the suction adjusting valve 11, a cylinder 112 that communicates with the suction flow path 115 via the aforementioned sleeve 117 is formed coaxially with the sleeve 117.

[0132] The cylinder 112 is configured to form an airtight chamber by being blocked at the end portion on the side opposite to the formation side of the sleeve 117 by an end plate 118 in a state in which the valve shaft 116a is inserted into the sleeve 117, and to divide the airtight chamber (cylinder) 112 into two chambers by a pressure receiving body 119, i.e., a piston of the present embodiment, connected to the other end of the valve shaft 116a, thereby forming a closed valve pressure chamber 113 of the suction adjusting valve 11 on the side of the end plate 118, and forming an auxiliary pressure chamber 114 on the side opposite to the closed valve pressure chamber 113 across the piston 119.

[0133] In the illustrated configuration, in order to make the suction adjusting valve 11 a normally open (NO) type, a spring 114a that presses the piston 119 toward the closed valve pressure chamber 113 is accommodated in the aforementioned auxiliary pressure chamber 114, and the auxiliary pressure chamber 114 is provided with a function as a spring chamber, but as long as the suction adjusting valve 11 can be made a normally open type, the spring 114a does not necessarily have to be provided in the auxiliary pressure chamber 114.

[0134] In addition, in the illustrated configuration, a configuration in which not only the valve body 116 and the valve seat 115a are provided inside the common body (valve case) 111, but also the cylinder 112, the piston 119, and the like for moving the valve body 116 in and out are provided inside the common body (valve case) 111 is shown, but as described with reference to​​Figure 8 As with the existing engine-driven compressor described above, the compressor adopts a structure in which the intake regulating valve body, which does not have a valve body drive mechanism, and the unloading regulator, which drives the valve body of the intake regulating valve body, are each separate. In this case, the aforementioned closed valve pressure chamber 113, auxiliary pressure chamber 114, and pressure body 119 are formed in the unloading regulator.

[0135] In addition, in the illustrated embodiment, a piston 119 that moves under the pressure of compressed gas introduced into the closed valve pressure chamber 113 is used as the pressure receiving body, and the airtight chamber, i.e., cylinder 112, which serves as the drive mechanism for valve body 116, is divided. However, the pressure receiving body 119 is not limited to the aforementioned piston. It can be used as long as the operation of valve body 116 can be controlled by the compressed gas introduced into the closed valve pressure chamber 113. For example, a diaphragm or the like can also be used as the pressure receiving body 119.

[0136] (Flow path for control)

[0137] The closed-valve pressure chamber 113 of the intake regulating valve 11 configured as described above is connected not only to the aforementioned control flow path 12, but also to the first bypass flow path 21 and the second bypass flow path 22 (see reference). Figures 1 to 4 The pressure chamber 113 of the suction regulating valve 11 is connected to the discharge side (receiving container 60) of the compressor body 10 via the first bypass flow path 21 and the second bypass flow path 22, and can use the pressure in the receiving container 60 as the working pressure to make the suction regulating valve 11 close.

[0138] exist Figure 1 The illustrated embodiment shows the following configuration: the other end of a common flow path 25, which is connected to the receiving container 60 at one end, is branched by connecting to an aluminum alloy branching block 26. One end of the control flow path 12, the first bypass flow path 21, and the second bypass flow path 22 are respectively connected to the branching block 26, and the other ends of the control flow path 12, the first bypass flow path 21, and the second bypass flow path 22 are respectively connected to the closed-valve pressure chamber 113 of the intake regulating valve 11. However, one end of the control flow path 12, the first bypass flow path 21, and the second bypass flow path 22 may also not be connected to the receiving container 60 via the aforementioned branching block 26 and common flow path 25, but rather as follows... Figure 3 and Figure 4 It is directly connected to the receiving container 60 as shown.

[0139] A first solenoid valve 23 is provided in the first bypass flow path 21 to open and close the first bypass flow path 21, and a second solenoid valve 24 is provided in the second bypass flow path 22 to open and close the second bypass flow path 22.

[0140] The first electromagnetic valve 23 is a normally open (NO) type electromagnetic valve, and is not an electromagnetic valve that performs an opening operation at the time of generation of a large pressure difference (overrun) between the primary side and the secondary side. Therefore, an electromagnetic valve having a lower maximum working pressure difference than the maximum pressure difference (pressure difference at the time of closing at the time of overrun) that can be generated between the primary side and the secondary side of the first electromagnetic valve 23 can be used, and a configuration in which a pressure reducing valve is not provided on the primary side of the first electromagnetic valve 23 can be formed.

[0141] On the other hand, as the second electromagnetic valve 24 provided in the second bypass passage 22, a normally closed (NC) type electromagnetic valve having a higher maximum working pressure difference than the maximum pressure difference (pressure difference at the time of closing at the time of overrun) that can be generated between the primary side and the secondary side of the second electromagnetic valve 24 in the second bypass passage 22 is used.

[0142] In addition, in Figures 1 to 3 , the reference numeral 27 is a three-way electromagnetic valve, the C port of the three-way electromagnetic valve 27 is made to communicate with the auxiliary pressure receiving chamber 114 (spring chamber) of the suction adjusting valve 11 via a passage 28c, the passage 28a installed to the A port is made to communicate with the suction passage 115 of the suction adjusting valve 11 on the secondary side of the valve seat 115a, and the passage 28b installed to the B port is made to communicate with the primary side of the suction adjusting valve 11, so as to be released to the atmosphere via an air cleaner (not shown) installed to the primary side of the suction adjusting valve 11.

[0143] Thus, the auxiliary pressure receiving chamber 114 of the suction adjusting valve 11 is made to be selectively communicated with the suction passage 115 on the secondary side of the valve seat 115a and the primary side of the suction adjusting valve 11 by switching of the three-way electromagnetic valve 27.

[0144] (Switches, sensors, and the like)

[0145] The engine-driven compressor 1 configured as described above is provided with a controller 30 described later that controls the operation of each part of the engine-driven compressor 1, and is provided with switches, sensors, and the like (see Figure 5 ) that output electric signals to the controller 30.

[0146] As the switches, switches for performing (for causing the controller 30 described later to perform) operations such as turning on / off of the main power supply of the engine-driven compressor 1, starting of the engine, starting and stopping of purge, and the like can be provided.

[0147] As one example, in the embodiment shown in Figure 5 , a main switch 70, a start switch 72, and a purge switch 71 are provided as such switches on an operation panel of the engine-driven compressor 1.

[0148] The main switch 70 is configured to be able to switch between "off" and "on" of the main power supply by rotation.

[0149] The "off" is a state of stopping energization to each part of the engine-driven compressor 1, and the "on" is a so-called "accessory position" which is a state of energization to the engine and an electronic control device such as the controller 30, various sensors, and measuring instruments.

[0150] Further, the start switch 72 is a switch for starting the engine, and if the start switch 72 is pressed for a predetermined time (for example, 1 second) or more, the starter motor of the engine is energized, and the engine is started.

[0151] With the configuration of the engine-driven compressor 1 provided with the main switch 70 and the start switch 72, the engine-driven compressor 1 is configured to be able to start and continue the operation by rotating the main switch 70 from the "off position to the "on position and starting the engine by pressing the start switch 72, and to be able to stop the engine-driven compressor 1 by rotating the main switch 70 from the "on position to the "off position.

[0152] Further, the switch for the start and stop operation of the engine-driven compressor 1 is not limited to the configuration in which the main switch 70 and the start switch 72 are separately provided as described above, and various configurations can be adopted as long as the on / off of the accessory (main switch) and the on / off of the starter motor can be performed, and the switch for the on / off of the accessory and the on / off of the starter motor can be configured by a known key switch or the like which is able to switch from the off position to the on position (accessory position) and further to a start position in which the starter motor of the engine is rotated by inserting a key and rotating the key.

[0153] Further, Figure 5 The reference numeral 71 in the drawing is a purge switch for instructing the start and stop of the discharge (purge) of the compressed gas in the receiving container 60, and the controller 30 described later starts the discharge of the compressed gas in the receiving container 60 by energizing the purge switch 71, and stops the discharge by deenergizing the purge switch 71.

[0154] In the illustrated example, the purge switch 71 is configured by a changeover switch, and is configured to be switched to the on state by one pressing operation of the purge switch 71 in the off state, and to be returned to the off state by one further pressing operation of the purge switch 71 from the on state.

[0155] However, the configuration of the purge switch 71 is not limited to the illustrated example, and various known switches such as a toggle switch can be adopted as long as the switch can be switched between the on and off.

[0156] In addition, the engine-driven compressor 1 of the present invention is provided with a pressure sensor 65 for detecting the pressure inside the receiving container 60. Figure 1 , 3 ~5), the controller 30 monitors the pressure changes inside the receiving container 60 based on the detection signal from the pressure sensor 65.

[0157] Furthermore, the engine-driven compressor 1 of the present invention is equipped with a temperature sensor 51 for detecting the discharge temperature of the compressor body 40. Figure 1 , 3 ~5), the controller 30 monitors the change in the discharge temperature of the compressor body 40 based on the detection signal from the temperature sensor 51.

[0158] (Controller)

[0159] The engine-driven compressor 1 of the present invention, configured as described above, is equipped with a controller 30 as an electronic control device. The controller 30 controls the operation of the first solenoid valve 23, the second solenoid valve 24, and the three-way solenoid valve 27 based on the aforementioned switching operations, the pressure change in the receiving container 60 detected by the pressure sensor 65, and the change in the discharge temperature of the compressor body 40 detected by the temperature sensor 51.

[0160] The controller 30 performs the following control based on the operating states of the aforementioned switches 70, 71, and 72, the pressure detected by the pressure sensor 65 inside the receiving container 60, and the discharge temperature of the compressor body 40 detected by the temperature sensor 51.

[0161] (1) Start-up and operation

[0162] After the operator turns the main switch 70 to the "on" position (refer to...), Figure 6 If the start switch 72 is pressed and held for an extended period, the controller 30, while maintaining the first solenoid valve 23 in a non-energized (cut-off) state (i.e., open state), energizes (opens) the second solenoid valve 24 to open it, thereby causing the starter motor to rotate and start the engine. Figure 6 (T2).

[0163] Therefore, if the pressure inside the receiving container 60 rises due to the rotation of the compressor body 40 and exceeds the working pressure of the suction regulating valve 11, then the suction regulating valve 11 closes. Figure 6 T3), such as Figure 3As shown in (A), the first solenoid valve 23 is kept open in a non-energized (cut-off) state, and the second solenoid valve 24 is opened by energizing (conducting), and the "start-up operation" of the engine warm-up operation is performed in a no-load state where the intake regulating valve 11 closes the intake port 41 of the compressor body 40 until the predetermined release condition is met.

[0164] Additionally, in the setting Figure 1 and Figure 3 With the configuration of the three-way solenoid valve 27 shown, when the controller 30 starts operating, it switches the three-way solenoid valve 27 to a position that connects the auxiliary pressure chamber 114 of the intake regulating valve 11 with the intake flow path 115 in the secondary side of the valve seat 115a (the position that connects the ports CA).

[0165] As a result, when the engine starts, the auxiliary pressure chamber 114 of the intake regulating valve 11 can be made to be under negative pressure, thereby enabling the intake regulating valve 11 to close earlier during engine start.

[0166] (2) Normal operation

[0167] If the aforementioned start-up and operation release conditions are met, the controller 30 will switch the first solenoid valve 23, which is in a de-energized (cut-off) state, to an energized (conducting) state, and switch the second solenoid valve 24, which is in an energized (conducting) state, to a de-energized (cut-off) state. Figure 6 (T4).

[0168] Therefore, as Figure 3 As shown in (B), both the first solenoid valve 23 and the second solenoid valve 24 are in the closed state. The working pressure is controlled by the control flow path 12 and the pressure regulating valve 13 to introduce the working pressure into the closed valve pressure chamber 113 of the suction regulating valve 11, and transfer to the "normal operation" of the compressor body 40 for suction control.

[0169] In this embodiment, the configuration is as follows: when the discharge temperature of the compressor body 40 detected by the temperature sensor 51 is lower than 60°C at the start of normal operation, the aforementioned "start-up operation" is stopped and the system switches to "normal operation" when either the temperature detected by the temperature sensor 51 reaches 60°C or the timer 36 calculates that 120 seconds have elapsed since the engine started. Furthermore, when the discharge temperature of the compressor body detected by the temperature sensor 51 is 60°C or higher at the start of normal operation, the aforementioned "start-up operation" is stopped and the system switches to "normal operation" when the timer 36 calculates that 30 seconds have elapsed since the engine started.

[0170] When the transition to the normal operation is made, the pressure in the receiving container 60 is still lower than the operating pressure of the pressure adjusting valve 13, and no compressed gas is introduced into the valve-closing pressure chamber 113 of the suction adjusting valve 11, so the suction adjusting valve 11 is opened (see Figure 3 (B) of FIG. 10, Figure 6 T4 of FIG. 11), and the compressor main body 40 starts to compress the gas, and the pressure in the receiving container 60 rises.

[0171] Then, if the pressure in the receiving container 60 rises above a predetermined rated pressure, the pressure adjusting valve 13 is opened and the suction adjusting valve 11 is closed, and if the pressure in the receiving container 60 falls below the rated pressure due to, for example, consumption of the compressed gas on the consumption side, the pressure adjusting valve 13 is closed and the suction adjusting valve 11 is opened, and the compressor main body 40 starts to compress the gas, and by repeating such operations, in the normal operation, the known suction control is performed so that the pressure of the compressed gas supplied to the consumption side approaches the aforementioned rated pressure.

[0172] Further, in the configuration in which the three-way electromagnetic valve 27 shown in Figure 1 and Figure 3 is provided, the controller 30 is configured to switch the three-way electromagnetic valve 27 to a position in which the auxiliary pressure chamber 114 of the suction adjusting valve 11 is communicated with the primary side of the suction adjusting valve 11 at this normal operation, whereby the auxiliary pressure chamber 114 of the suction adjusting valve 11 is released to the atmosphere, and the suction adjusting valve 11 is able to perform the opening and closing operation in accordance with the change in the pressure in the receiving container 60 introduced into the valve-closing pressure chamber 113.

[0173] (3) Surge Avoidance Operation

[0174] The controller 30 monitors the pressure in the receiving container 60 based on the detection signal from the pressure sensor 65, and if the pressure in the receiving container 60 becomes equal to or higher than a surge pressure (P1) set to a predetermined high pressure, compared to the aforementioned rated pressure, the controller 30 switches the second electromagnetic valve 24 in the non-energized (off) state to the energized (on) state while maintaining the first electromagnetic valve 23 in the energized (on) state (see T5 of FIG. 12). Figure 6

[0175] Thus, although the first electromagnetic valve 23 is maintained in the closed state, the second electromagnetic valve 24 is opened, and the compressed gas from the receiving container 60 is introduced into the valve-closing pressure chamber 113 of the suction adjusting valve 11, so that the opening of the second electromagnetic valve 24 is slightly delayed, and the suction adjusting valve 11 is closed (see T6 of FIG. 13), and in the state in which the first electromagnetic valve 23 is closed, the second electromagnetic valve 24 is opened, and the suction adjusting valve 11 is closed, the surge avoidance operation is performed (see (C) of FIG. 14). Figure 3 ​​​

[0176] In addition, in the configuration of the three-way electromagnetic valve 27 shown in Figure 1 and Figure 3 , in the surge avoidance operation, the controller 30 switches the three-way electromagnetic valve 27 to a position in which the auxiliary pressure-receiving chamber 114 of the suction adjusting valve 11 is communicated with the primary side of the suction adjusting valve 11 and released to the atmosphere, in terms of this, the same as in the normal operation of (B) of Figure 3 .

[0177] From the period (T5 to T6 of Figure 6 ) until the suction adjusting valve 11 is closed, the pressure in the receiving vessel 60 slightly rises, but if the suction adjusting valve 11 is closed (T6 of Figure 6 ), the compressor main body 40 stops suctioning and no longer discharges compressed gas, and the compressed gas in the receiving vessel 60 is vented via the second bypass flow path 22 and the gas discharge flow path 14, so that the pressure in the receiving vessel 60 can be prevented from further rising.

[0178] Then, the controller 30 stops energization to the second electromagnetic valve 24 (T7 of Figure 6 ) if it is determined based on the detection signal of the pressure sensor 65 that the pressure in the receiving vessel 60 is a predetermined low pressure compared to the aforementioned surge pressure (P1) and becomes a recovery pressure (P2) or less that is set to be higher than the rated pressure.

[0179] Thus, the second electromagnetic valve 24 is closed, and the engine-driven compressor 1 returns to the normal operation in which the opening and closing operation of the suction adjusting valve 11 is controlled using the control flow path 12 and the pressure adjusting valve 13 as shown in (B) of Figure 3 .

[0180] Thus, in the engine-driven compressor 1 of the present application, configured to perform the closing of the suction adjusting valve 11 and the venting (purging) of the compressed gas at the time of surge occurrence by opening the second electromagnetic valve 24 constituted by an electromagnetic valve of a normally closed (NC) type having a high maximum working pressure difference. By maintaining the normally open (NO) type electromagnetic valve, that is, the first electromagnetic valve 23 in a closed state at the time of surge occurrence, it is not necessary to provide a pressure-reducing valve on the primary side of the first electromagnetic valve 23.

[0181] (4) Purging operation

[0182] In the configuration in which the engine-driven compressor 1 is provided with a purging switch 71 as shown in Figure 5 , the following "purging operation" can be performed: the operation is performed in a state in which the suction adjusting valve 11 is closed by the on operation of the purging switch 71 by the operator and the venting of the compressed gas is performed via the gas discharge flow path 14.

[0183] The operator turns on the purge switch 71, and if the controller 30 receives the on signal from the purge switch 71, the first electromagnetic valve 23 in the energized (on) state is switched to the de-energized (off) state, and the second electromagnetic valve 24 in the de-energized (off) state is switched to the energized (on) state, and the operation shifts to the purge operation (T8) of FIG. 10. Figure 7

[0184] Thus, the second electromagnetic valve 24 of the normally closed (NC) type having a high maximum working pressure difference is opened while being energized (on).

[0185] On the other hand, in the case of the first electromagnetic valve 23 of the normally open (NO) type having a low maximum working pressure difference, if the pressure difference between the primary side and the secondary side at the time of turning on the purge switch 71 is higher than the maximum working pressure difference, even if it is switched to the de-energized state by the on of the purge switch 71, it cannot immediately perform the opening operation but maintains the closed state (refer to (A) of FIG. 10, Figure 4 Figure 7 T8) of FIG. 10.

[0186] However, by opening the second electromagnetic valve 24 to introduce the compressed gas in the receiving container 60 to the closed valve pressure chamber of the suction adjusting valve 11 via the second bypass flow path 22, the suction adjusting valve 11 is closed (maintains the closed state in the illustrated example), so that not only the compressed gas is not discharged from the compressor main body 40, but also the compressed gas in the receiving container 60 is discharged via the second bypass flow path 22 and the discharge flow path 14, whereby the pressure in the receiving container 60 gradually decreases.

[0187] Then, if the pressure in the receiving container 60 decreases, the difference between the primary side pressure and the secondary side pressure of the first electromagnetic valve 23 becomes equal to or lower than the maximum working pressure difference of the first electromagnetic valve 23, the first electromagnetic valve 23 is opened (refer to T9 of FIG. 10), and the discharge of the compressed gas via the first bypass flow path 21 and the discharge flow path 14 also starts, and the pressure in the receiving container 60 further decreases. Figure 7

[0188] In addition, in the configuration provided with the three-way electromagnetic valve 27 shown in Figure 1 and Figure 3 (B) of FIG. 10, in the following aspects, it is the same as the normal operation of (B) of FIG. 10, that is, in the purge operation, the controller 30 switches the three-way electromagnetic valve 27 to a position where the auxiliary pressure chamber 114 of the suction adjusting valve 11 is communicated with the primary side of the suction adjusting valve 11 and is released to the atmosphere. Figure 3

[0189] ​​​​From the state where such purge operation is performed, if the operator switches the purge switch 71 to OFF, the controller switches the first solenoid valve 23 in the non-energized (OFF) state to the energized (ON) state, and switches the second solenoid valve 24 in the energized (ON) state to the non-energized (OFF) state, ending the purge operation. Figure 7

[0190] Thus, both the first solenoid valve 23 and the second solenoid valve 24 are closed, and the operation returns to the normal operation shown in (B) of FIG. 10. Figure 3

[0191] Further, in the illustrated embodiment, a configuration in which the "purge operation" is performed by the ON operation of the purge switch 71 by the operator is described, but on the basis of this configuration, the controller 30 can automatically start the purge operation when predetermined conditions are satisfied, regardless of the operation of the purge switch 71.

[0192] In this case, the configuration can be such that a detection member that detects the time of the no-load operation in which the suction control valve 11 is closed and a service pressure sensor that detects the pressure supplied to the air working machine or the like are provided, and if it is detected that the no-load operation has continued for a predetermined time (as one example, for example, 20 seconds), the controller 30 performs the "automatic purge operation" in which the first solenoid valve 23 is automatically switched to the non-energized (OFF) state and the second solenoid valve 24 in the non-energized (OFF) state is switched to the energized (ON) state, and the "automatic purge operation" is ended in accordance with the detection of the service pressure, and both the first solenoid valve 23 and the second solenoid valve 24 are closed to return to the normal operation.

[0193] In the case where the controller 30 can perform the "automatic purge operation" that automatically starts the purge operation, not based on the operation of the purge switch 71, as described above, the configuration can be such that the setting of whether or not the controller 30 performs such "automatic purge operation" can be changed, and in this case, a member (for example, a touch panel or the like) for the operator to input such setting change can be provided on the operation panel.

[0194] (5) Cooling operation

[0195] Further, the engine-driven compressor 1 is configured to perform a cooling operation in which the operation of the engine is continued until a predetermined end condition is satisfied (in the present embodiment, until a predetermined time elapses) after the main switch 70 is switched to the OFF position, and then stop the engine, and in this case, if the main switch 70 is switched to the OFF position, the controller 30 switches the first solenoid valve 23 in the energized (ON) state to the non-energized (OFF) state, and switches the second solenoid valve 24 in the non-energized (OFF) state to the energized (ON) state, and shifts to the cooling operation​​Figure 7 (T11).

[0196] Therefore, the normally closed (NC) type second solenoid valve 24, which has a high maximum operating pressure difference, opens simultaneously with energization (conduction). As a result, compressed gas is introduced into the receiving container 60 through the closed pressure chamber 113 of the intake regulating valve 11, causing the intake regulating valve 11 to close (maintain closed state). Figure 7 In the case of T11), the compressed gas is not discharged from the compressor body 40, while the compressed gas in the receiving container 60 is discharged through the second bypass flow path 22 and the vent flow path 14, thereby gradually reducing the pressure in the receiving container 60.

[0197] On the other hand, when the pressure difference between the primary and secondary sides is higher than the maximum working pressure difference when the main switch 70 is set to cut off, even if the normally open (NO) type solenoid valve, i.e., the first solenoid valve 23, which has a low maximum working pressure difference, switches to a non-energized state due to the cut-off of the main switch 70, it cannot immediately perform an opening action but remains in a closed state (see reference). Figure 7 When the pressure inside the receiving container 60 decreases (T11), the valve opens only when the pressure difference between the primary and secondary sides of the first solenoid valve 23 falls below the maximum operating pressure difference of the first solenoid valve 23 (refer to T11). Figure 7 T12), such as Figure 4 As shown in (B), not only is the compressed gas introduced into the closed valve pressure chamber 113 of the intake regulating valve 11 via the second bypass flow path 22 discharged through the vent flow path 14, but the compressed gas introduced into the closed valve pressure chamber 113 via the first bypass flow path 21 is also discharged through the vent flow path 14.

[0198] Additionally, in the setting Figure 1 and Figure 3 The three-way solenoid valve 27 shown in the diagram is similar to the following aspects: Figure 3 The operation of (B) is the same as during normal operation, that is, during this cooling operation, the controller 30 switches the three-way solenoid valve 27 to a position that releases the auxiliary pressure chamber 114 of the intake regulating valve 11 into the atmosphere by connecting it to the primary side of the intake regulating valve 11.

[0199] On the other hand, if the timer 36 calculates that a predetermined time has elapsed since the start of the cooling operation, the controller 30 stops the engine and stops energizing the second solenoid valve 24. Figure 7 (T13).

[0200] Thus, although the second electromagnetic valve 24 of the normally closed (NC) type is closed, the first electromagnetic valve of the normally open (NO) type is maintained in an open state, so that the compressed gas in the receiving vessel 60 continues to be discharged via the first bypass flow path 21 and the discharge flow path 14, and as a result of the decrease in the pressure in this receiving vessel 60, the pressure in the closing valve pressure chamber 113 of the suction adjusting valve 11 also decreases, and the suction adjusting valve 11 opens Figure 7 the T14), in this state, the operation of the engine-driven compressor 1 is completely stopped.

Claims

1. An operation control method of an engine-driven compressor characterized by comprising: the engine-driven compressor including an engine, a compressor main body driven by the engine, and a suction adjusting device that controls suction to the compressor main body, the suction adjusting device including: a suction adjusting valve that opens and closes a suction port of the compressor main body; a control flow path that communicates between a closed-valve pressure chamber of the suction adjusting valve and a discharge side of the compressor main body; and a pressure adjusting valve that opens the control flow path when a discharge side pressure of the compressor main body is a predetermined rated pressure or more and closes the control flow path when the discharge side pressure of the compressor main body is less than the rated pressure, the engine-driven compressor being provided with: first and second bypass flow paths that bypass the pressure adjusting valve and communicate between the discharge side of the compressor main body and the closed-valve pressure chamber of the suction adjusting valve, respectively; a bleed flow path that throttles and bleeds compressed gas in the closed-valve pressure chamber of the suction adjusting valve; a first electromagnetic valve that opens and closes the first bypass flow path; and a second electromagnetic valve that opens and closes the second bypass flow path, the first electromagnetic valve being provided as a normally open electromagnetic valve, and the second electromagnetic valve being provided as a normally closed electromagnetic valve having a maximum working pressure difference that is higher than a maximum pressure difference that can be generated between a primary side and a secondary side of the second electromagnetic valve, performing a start-up operation in which the engine is started in a state in which the first electromagnetic valve is non-energized, after the engine is started, when a predetermined start-up operation release condition is satisfied, stopping the start-up operation by energizing the first electromagnetic valve and de-energizing the second electromagnetic valve, shifting to a normal operation in which suction is controlled by the suction adjusting device, and in the normal operation, when a pressure on the discharge side of the compressor main body becomes an overshoot pressure that is set to a predetermined high pressure or more with respect to the rated pressure, energizing the second electromagnetic valve in a state in which the first electromagnetic valve is maintained in an energized state, and performing an overshoot avoidance operation in which a no-load operation in which the suction adjusting valve is closed is shifted to.

2. The operation control method of the engine-driven compressor according to claim 1, characterized by comprising: in the overshoot avoidance operation, when the pressure on the discharge side of the compressor main body is a predetermined low pressure with respect to the overshoot pressure and becomes a recovery pressure that is higher than the rated pressure or less, de-energizing the second electromagnetic valve to end the overshoot avoidance operation and return to the normal operation.

3. The operation control method of the engine-driven compressor according to claim 1 or 2, characterized by comprising: energizing the second electromagnetic valve during the start-up operation.

4. The operation control method of the engine-driven compressor according to claim 1 or 2, characterized by comprising: The engine-driven compressor is provided with a purge switch. With the purge switch turned on, purge operation is started in which the first solenoid valve is de-energized and the second solenoid valve is energized. With the purge switch turned off, the purge operation is ended in which the first solenoid valve is energized and the second solenoid valve is de-energized, and the normal operation is resumed.

5. The operation control method of an engine-driven compressor according to claim 1 or 2, characterized in that, with the main switch turned off, cooling operation is performed in which the first solenoid valve is de-energized and the second solenoid valve is energized to continue the operation of the engine, and when a predetermined end condition is satisfied, the second solenoid valve is de-energized and the engine is stopped to end the cooling operation.

6. An engine-driven compressor characterized by comprising: an engine, a compressor main body driven by the engine, and a suction adjusting device that controls suction to the compressor main body, the suction adjusting device includes: a suction adjusting valve that opens and closes a suction port of the compressor main body; a control flow path that communicates between a closed-valve pressure chamber of the suction adjusting valve and a discharge side of the compressor main body; and a pressure adjusting valve that opens the control flow path when a discharge side pressure of the compressor main body is a predetermined rated pressure or higher, and closes the control flow path when the discharge side pressure of the compressor main body is lower than the rated pressure, the engine-driven compressor is provided with: first and second bypass flow paths that bypass the pressure adjusting valve and communicate between the discharge side of the compressor main body and the closed-valve pressure chamber of the suction adjusting valve; a bleed flow path that throttles and bleeds compressed gas in the closed-valve pressure chamber of the suction adjusting valve; a first solenoid valve that opens and closes the first bypass flow path; a second solenoid valve that opens and closes the second bypass flow path; and a controller that controls energization of the first and second solenoid valves to switch operation states, the first solenoid valve is a normally open solenoid valve, and the second solenoid valve is a normally closed solenoid valve having a maximum working pressure difference that is higher than a maximum pressure difference that can be generated between a primary side and a secondary side of the second solenoid valve, the controller is configured to: perform start-up operation in which the engine is started with the first solenoid valve de-energized, after the engine is started, when a predetermined start-up operation release condition is satisfied, the start-up operation is stopped with the first solenoid valve energized and the second solenoid valve de-energized, the normal operation in which suction is controlled by the suction adjusting device is shifted to, and in the normal operation, when a pressure of the discharge side of the compressor main body becomes an overshoot pressure that is set to a predetermined high pressure or higher with respect to the rated pressure, the second solenoid valve is energized with the first solenoid valve maintained in an energized state, and an overshoot avoidance operation in which the suction adjusting valve is closed is shifted to.

7. The engine-driven compressor according to claim 6, characterized in that, In the surge avoidance operation, when the pressure on the discharge side of the compressor main body is a predetermined low pressure relative to the surge pressure and becomes a recovery pressure lower than the rated pressure, the controller de-energizes the second electromagnetic valve to end the surge avoidance operation and return to the normal operation.

8. The engine-driven compressor according to claim 6 or 7, characterized in that, the controller energizes the second electromagnetic valve at the start operation.

9. The engine-driven compressor according to claim 6 or 7, characterized in that, the engine-driven compressor includes a purge switch, the controller starts a purge operation in which the first electromagnetic valve is de-energized and the second electromagnetic valve is energized using the conduction of the purge switch, ends the purge operation in which the first electromagnetic valve is energized and the second electromagnetic valve is de-energized using the disconnection of the purge switch, and returns to the normal operation.

10. The engine-driven compressor according to claim 6 or 7, characterized in that, the controller performs a cooling operation in which the first electromagnetic valve is de-energized and the second electromagnetic valve is energized using the disconnection of a main switch to continue the operation of the engine, de-energizes the second electromagnetic valve when a predetermined end condition is satisfied, and stops the engine to end the cooling operation.

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