JP2011099348A - Air compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air compressor reducing operation pressure of a suction throttle valve during no-load operation while suppressing an increase in the size of the suction throttle valve and, eventually, reducing the delivery pressure of a compressor body during the no-load operation and enhancing an energy-saving effect. <P>SOLUTION: A three-way valve 22 is provided so that any one of control paths 21A and 21B is selected and made to communicate with a control path 21C. When performing load operation, a control device 5 controls the three-way valve 22 so that the control path 21A is made to communicate with the control path 21C, thereby allowing the spring chamber 16 of the suction throttle valve 3 to communicate with a primary chamber 11. Meanwhile, when switching from the load operation to the non-load operation, the control device controls the three-way valve 22 so that the control path 21B is made to communicate with the control path 21C, thereby allowing the spring chamber 16 of the suction throttle valve 3 to communicate with a secondary chamber 12. Thereby, pressure in the spring chamber 16 of the suction throttle valve 3 is controlled. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air compressor provided with a suction throttle valve provided on the suction side of a compressor body.

  The air compressor includes, for example, a compressor main body that compresses air, and a suction throttle valve provided on the suction side of the compressor main body (see, for example, Patent Document 1).

  The suction throttle valve is slidably provided in the cylinder, a valve body for opening and closing the valve seat, a primary chamber upstream of the valve seat, a secondary chamber downstream of the valve seat, and a cylinder. And a shaft that is connected to the piston and into which a valve body is slidably inserted in a small-diameter portion on the distal end side. The cylinder is partitioned by a piston, and a spring chamber is formed on one side in the sliding direction of the piston in the cylinder, and an operation chamber is formed on the other side in the sliding direction of the piston in the cylinder. A spring is housed in the spring chamber, and the force of this spring acts on the piston as a biasing force in the opening direction of the valve body. Further, the pressure in the operation chamber acts on the piston as a biasing force in the closing direction of the valve body.

  A first discharge path is branchedly connected to the discharge path of the compressor body, and the first discharge path is connected to the operation chamber of the suction throttle valve. An air release valve is provided in the first air release path. A second air release path is connected between the operation chamber of the suction throttle valve and the primary chamber.

  For example, when performing full load operation, by closing the discharge valve, the compressed air on the discharge side of the compressor body is not led to the operation chamber and the primary chamber of the suction throttle valve, Since the primary chamber communicates with the primary chamber, the pressure in the operation chamber is almost atmospheric pressure. As a result, the biasing force in the opening direction of the valve body by the force of the spring exceeds the biasing force in the closing direction of the valve body by the pressure in the operation chamber, the piston slides in the opening direction of the valve body, The valve body slides in the opening direction due to the pressure difference with the next chamber, and the valve seat is fully opened. As a result, the compressor body sucks air through the suction throttle valve and compresses it.

  On the other hand, for example, when performing no-load operation, by opening the release valve, compressed air on the discharge side of the compressor body is led to the operation chamber and the primary chamber of the suction throttle valve, and the compressor body While the discharge side pressure decreases, the pressure in the operation chamber increases. As a result, the urging force in the closing direction of the valve body due to the pressure in the operation chamber is superior to the urging force in the opening direction of the valve body due to the spring force, the valve body operates in the closing direction together with the piston, and the valve seat is fully closed. As a result, the compressor body is operated in a state where the suction side of the compressor body is shut off and the discharge side pressure of the compressor body is reduced.

JP 2008-175152 A

  In the above prior art, when performing no-load operation, the urging force in the closing direction of the valve body due to the pressure in the operation chamber is made larger than the urging force in the opening direction of the valve body due to the spring force to close the valve body in the closing direction. Is supposed to work. Therefore, the pressure in the operation chamber of the suction throttle valve during no-load operation needs to be increased to overcome the spring force, which hinders the reduction of the discharge side pressure of the compressor body that is the pressure source. . If the discharge side pressure during no-load operation increases, the power of the compressor body also increases and the energy saving effect decreases. In particular, due to improvements in the rotor in recent years, it is possible to operate the rotor stably even if the pressure difference between the suction side pressure and the discharge side pressure of the compressor body becomes small, and noise can be reduced. Therefore, it has been desired to reduce the discharge side pressure during no-load operation.

  Therefore, as one of methods for reducing the discharge side pressure of the compressor body during no-load operation, that is, the operation pressure of the suction throttle valve, for example, a method of increasing the diameter of the piston (in other words, the cross-sectional area). Conceivable. However, in this case, the suction throttle valve is increased in size. More specifically, for example, the discharge side pressure is set to 0 on the condition that the discharge side pressure of the compressor body during no-load operation is 0.2 MPa, the diameter of the piston of the suction throttle valve is 100 mm, and the spring force is 700 N. To reduce the pressure to 1 MPa, the piston diameter must be increased to about 140 mm (about 1.4 times).

  The object of the present invention is to reduce the operating pressure of the suction throttle valve during no-load operation while suppressing an increase in the size of the suction throttle valve, thereby reducing the discharge side pressure of the compressor body during no-load operation. An object of the present invention is to provide an air compressor that can increase the energy saving effect.

  (1) In order to achieve the above object, the present invention includes a compressor body that compresses air, and a suction throttle valve that is provided on the suction side of the compressor body. A valve body that opens and closes the valve seat, a primary chamber upstream of the valve seat, a secondary chamber downstream of the valve seat, and is slidably provided in the cylinder and connected to the valve body A piston, a spring chamber defined by the piston in the cylinder and positioned on one side in the sliding direction of the piston, and housed in the spring chamber, and the biasing force in the opening direction of the valve body is stored in the piston A spring that acts on the piston, and an operation chamber that is defined by the piston in the cylinder and is located on the other side in the sliding direction of the piston, and in which an internal pressure acts on the piston as an urging force in the closing direction of the valve body; When performing load operation, the compression The pressure inside the operation chamber is lowered without leading the compressed air on the discharge side of the main body to the operation chamber, thereby causing the valve body to operate in the opening direction together with the piston to open the valve seat, and from no load operation to no load When switching to operation, the compressed air on the discharge side of the compressor body is led to the operation chamber to increase the pressure in the operation chamber, thereby operating the valve body together with the piston in the closing direction to move the valve seat. In the air compressor which closes, when the load operation is performed, the spring chamber is communicated with the primary chamber or a region under substantially atmospheric pressure, and when the load operation is switched to the no-load operation, the spring chamber is connected to the secondary chamber. Spring chamber pressure control means for communicating and controlling the pressure in the spring chamber is provided.

  In the present invention, when performing a load operation, the spring chamber of the suction throttle valve is communicated with the primary chamber (or a region under almost atmospheric pressure), and the pressure in the spring chamber is controlled to be almost atmospheric pressure. On the other hand, when switching from the load operation to the no-load operation, the spring chamber of the suction throttle valve is communicated with the secondary chamber, and control is performed so that the pressure in the spring chamber becomes substantially a vacuum pressure. The negative pressure in the spring chamber serves to assist the biasing force in the closing direction of the valve body due to the pressure (positive pressure) in the operation chamber. Therefore, for example, the pressure in the operation chamber can be reduced without increasing the cross-sectional area of the piston of the suction throttle valve. Therefore, it is possible to reduce the operation pressure of the suction throttle valve during no-load operation while suppressing an increase in the size of the suction throttle valve, and thus reduce the discharge side pressure of the compressor body during no-load operation. . As a result, the power of the compressor body during no-load operation can be reduced, and the energy saving effect can be enhanced.

  (2) In the above (1), preferably, when performing a load operation, the spring chamber pressure control means communicates the spring chamber with the primary chamber or a region under substantially atmospheric pressure, When the pressure is controlled to be almost atmospheric pressure and the load operation is switched to the no-load operation, the spring chamber is communicated with the secondary chamber so that the pressure in the spring chamber is almost a vacuum pressure. To do.

  (3) In the above (1) or (2), preferably, the spring chamber pressure control means communicates with the first control path communicating with the primary chamber or a region under substantially atmospheric pressure, and the secondary chamber. The second control path, the third control path communicating with the spring chamber, the third control path by selecting one of the first control path and the second control path A three-way valve that communicates with the first control path and the third control path when the load operation is performed, the three-way valve is controlled so that the load operation is switched to the no-load operation. And a control device that controls the three-way valve so as to communicate the second control path and the third control path.

  (4) In the above (3), preferably, the spring chamber pressure control means has a check valve provided in the second control path to prevent a back flow from the secondary chamber to the spring chamber.

  (5) In any one of the above (1) to (4), the compressed air on the discharge side of the compressor main body is preferably branched and connected to the discharge path of the compressor main body to the operation chamber. In addition, an air discharge path for discharging to the primary chamber or an area under almost atmospheric pressure and an air discharge path provided in the air discharge path are closed when performing load operation, and when performing no load operation. And an air release valve that is switched to an open state.

  According to the present invention, it is possible to reduce the operating pressure of the suction throttle valve during no-load operation while suppressing an increase in the size of the suction throttle valve, and thus reduce the discharge side pressure of the compressor body during no-load operation. Can increase the energy saving effect.

It is the schematic showing the structure of the air compressor in one Embodiment of this invention. It is the schematic for demonstrating operation | movement of the air compressor in one Embodiment of this invention, and shows the state of load operation. It is the schematic for demonstrating operation | movement of the air compressor in one Embodiment of this invention, and shows the state of a no-load driving | operation.

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

  FIG. 1 is a schematic diagram illustrating a configuration of an air compressor in the present embodiment. 2 and 3 are schematic diagrams for explaining the operation of the air compressor in the present embodiment. FIG. 2 shows a load operation state, and FIG. 3 shows a no-load operation state. The dotted lines in FIGS. 2 and 3 indicate portions where the air flow is blocked.

  1 to 3, an oil supply type air compressor includes an electric motor 1, a compressor main body 2 driven by the electric motor 1 to compress air, and a suction provided on the suction side of the compressor main body 2. A throttle valve 3, a suction filter (not shown) provided on the upstream side of the suction throttle valve, an oil separator 4 provided on the discharge side of the compressor body 2, and a control device 5 are provided.

  The oil separator 4 separates oil in the compressed air discharged from the compressor body 2. The oil separated by the oil separator 4 is stored in the oil separator 4 and then supplied to the working chamber of the compressor body 2 through an oil supply path (not shown). Yes. On the other hand, the compressed air separated by the oil separator 4 is supplied to the use destination of the compressed air via the compressed air supply path 6. The compressed air supply path 6 is provided with a pressure regulating valve (check valve) 7, and a cooler and a dehumidifier (not shown) are provided on the downstream side thereof. Further, a pressure sensor 8 is provided on the downstream side of the pressure regulating valve 7, and the pressure detected by the pressure sensor 8 (that is, the pressure on the downstream side of the pressure regulating valve 7 and varies depending on the amount of compressed air used). Pressure) to be output to the control device 5.

  The suction throttle valve 3 includes a valve seat 9, a valve body 10 that opens and closes the valve seat 9, a primary chamber 11 that is upstream of the valve seat 9, a secondary chamber 12 that is downstream of the valve seat 9, It has a piston 14 slidably provided in the cylinder 13 and a shaft 15 connected to the piston 14 and through which a valve body 10 is slidably inserted in a small diameter portion on the tip side. The cylinder 13 is partitioned by a piston 14, and a spring chamber 16 is formed on one side (left side in the figure) of the piston 14 in the cylinder 13. An operation chamber (pressurizing chamber) 17 is formed in the middle right). A spring 18 is accommodated in the spring chamber 16, and the force of the spring 18 acts on the piston 14 as an urging force in the opening direction of the valve body 10 (right side in the figure). Further, the pressure in the operation chamber 17 acts on the piston 14 as an urging force in the closing direction (left side in the figure) of the valve body 10.

  An air discharge path 19A is connected between the oil separator 4 and the operation chamber 17 of the suction throttle valve 3, and an air discharge valve (electromagnetic valve) 20 is provided in the air discharge path 19A. In addition, the air discharge path 19B is branched from the downstream side of the air discharge valve 20 in the air discharge path 19A, and the air discharge path 19B is used as the primary chamber 10 of the suction throttle valve 3 (or as a region under almost atmospheric pressure, for example, The suction throttle valve 3 may be connected upstream of the primary chamber 10 and downstream of the suction filter.

  Further, as major features of the present embodiment, a control path 21A that communicates with the primary chamber 11 of the suction throttle valve 3, a control path 21B that communicates with the secondary chamber 12 of the suction throttle valve 3, and a spring chamber of the suction throttle valve 3 A control path 21C that communicates with 16 and a three-way valve (electromagnetic valve) 22 that selects one of the control paths 21A and 21B and communicates with the control path 21C are provided. In addition, a check valve 23 for preventing a back flow from the secondary chamber 12 to the spring chamber 16 is provided in the control path 21B. Thereby, when the compressed air flows back into the secondary chamber 12 of the suction throttle valve when the compressor main body 1 is stopped, the compressed air containing oil flows through the control path 21B, the three-way valve 22, and the control path 21C. 16 is prevented.

  The control device 5 operates or stops the compressor main body 2 via the electric motor 1 based on an operation signal or a stop signal from an operation switch (not shown). The control device 5 stores preset pressure upper limit values and pressure lower limit values in an internal memory or the like, compares these pressure upper limit values and pressure lower limit values with the pressure detected by the pressure sensor 8, Based on the determination result, switching to load operation or no-load operation is performed. That is, for example, when the pressure detected by the pressure sensor 8 during the load operation rises to the pressure upper limit value, the load operation is switched to the no-load operation. Further, for example, when the pressure detected by the pressure sensor 8 during the no-load operation decreases to the pressure lower limit value, the no-load operation is switched to the load operation.

  And when performing load driving | operation (refer FIG. 2), the control apparatus 5 controls the air release valve 20 to a closed state. As a result, the compressed air in the oil separator 4 is not led out to the operation chamber 17 and the primary chamber 11 of the suction throttle valve 3, and the operation chamber 17 and the primary chamber 11 are in communication with each other. Becomes the same as the pressure of the primary chamber 11 (approximately atmospheric pressure). Further, the control device 5 controls the three-way valve 22 to cause the control path 21A and the control path 21C to communicate with each other. Thereby, the spring chamber 16 of the suction throttle valve 3 and the primary chamber 11 communicate with each other, and the pressure in the spring chamber 16 becomes the same as the pressure in the primary chamber 11. Thereby, the biasing force in the opening direction of the valve body 10 by the force of the spring 18 is applied in the closing direction of the valve body 10 by the pressure in the operation chamber 17 (specifically, the pressure difference between the operation chamber 17 and the spring chamber 16). The piston 14 slides in the opening direction of the valve body 10, and the valve body 10 slides in the opening direction due to the pressure difference between the primary chamber 11 and the secondary chamber 12, and the valve seat 9 is in the open state. Become. As a result, the compressor body 2 sucks air through the suction filter and the suction throttle valve 3 and compresses the air.

  On the other hand, when switching from load operation to no-load operation (see FIG. 3), the control device 5 controls the air release valve 20 to be in an open state. Thereby, the compressed air in the oil separator 4 is led out to the operation chamber 17 and the primary chamber 11 of the suction throttle valve 3, and the pressure in the oil separator 4 (in other words, the discharge side pressure of the compressor body 2) is reduced. At the same time, the pressure in the operation chamber 17 of the suction throttle valve 3 increases. Further, the control device 5 controls the three-way valve 22 so as to communicate the control path 21B and the control path 21C. As a result, the spring chamber 16 and the secondary chamber 12 of the suction throttle valve 3 communicate with each other, and the pressure in the spring chamber 16 becomes the same as the pressure in the primary chamber 12 (for example, a substantially vacuum pressure of about −100 kPa). Thereby, the biasing force in the closing direction of the valve body 10 due to the pressure in the operation chamber 17 (specifically, the pressure difference between the operation chamber 17 and the spring chamber 16) is applied in the opening direction of the valve body 10 by the force of the spring 18. Overcoming the force, the valve body 10 moves in the closing direction together with the piston 14, and the valve seat 9 is closed. As a result, the compressor body 2 is operated in a state where the suction side of the compressor body 2 is blocked and the discharge side pressure of the compressor body 2 is reduced.

  As described above, in the present embodiment, control is performed so that the pressure in the spring chamber 16 of the suction throttle valve 3 becomes substantially a vacuum pressure during no-load operation. The negative pressure in the spring chamber 16 serves to assist the biasing force in the closing direction of the valve body 10 due to the pressure (positive pressure) in the operation chamber 17. Thus, for example, the operation pressure of the suction throttle valve 3 during no-load operation can be reduced without increasing the cross-sectional area of the piston 14. Therefore, it is possible to reduce the operating pressure of the suction throttle valve 3 during no-load operation while suppressing an increase in the size of the suction throttle valve 3, and thus reduce the discharge side pressure of the compressor body 2 during the no-load operation. be able to. As a result, the power of the compressor body 2 during no-load operation can be reduced, and the energy saving effect can be enhanced. Specifically, for example, the discharge-side pressure of the compressor body 2 during no-load operation can be reduced from 0.2 MPa to 0.1 MPa, and in this case, the power can be reduced by about 40%, Energy saving effect can be enhanced.

  As another viewpoint, if the discharge side pressure of the compressor body 2 during the no-load operation is the same, the cross-sectional area of the piston 14 of the suction throttle valve 3 can be reduced, and the suction throttle valve 3 can be reduced in size. Can be achieved. As a result, material costs can be reduced.

  In the above description, the oil supply type air compressor that supplies oil to the working chamber of the compressor main body 2 is described as an example of application of the present invention, but the present invention is not limited thereto. That is, for example, the present invention may be applied to an oil-free air compressor that does not supply oil to the working chamber of the compressor body 2 or a water-supplying air compressor that supplies water to the working chamber of the compressor body 2. . Further, as an application target of the present invention, the air compressor that operates with the rotation speed of the electric motor 1 fixed is described as an example, but the present invention is not limited thereto. That is, for example, the present invention may be applied to an air compressor that is operated by variably controlling the rotation speed of the electric motor 1 with an inverter. In these cases, the same effect as described above can be obtained.

2 Compressor body 3 Suction throttle valve,
5 Control device (spring chamber pressure control means)
DESCRIPTION OF SYMBOLS 9 Valve seat 10 Valve body 11 Primary chamber 12 Secondary chamber 13 Cylinder 14 Piston 16 Spring chamber 17 Operation chamber 18 Spring 19A Air discharge path 19B Air discharge path 20 Air discharge valve 21A Control path (spring chamber pressure control means)
21B Control path (spring chamber pressure control means)
21C Control path (spring chamber pressure control means)
22 Three-way valve (spring chamber pressure control means)
23 Check valve (spring chamber pressure control means)

Claims (5)

A compressor main body for compressing air, and a suction throttle valve provided on the suction side of the compressor main body,
The suction throttle valve is slidable in a cylinder, a valve body that opens and closes the valve seat, a primary chamber upstream of the valve seat, a secondary chamber downstream of the valve seat, and a cylinder A piston provided and connected to the valve body; a spring chamber defined by the piston in the cylinder and positioned on one side in the sliding direction of the piston; and housed in the spring chamber; A spring that applies an urging force in the opening direction to the piston, and the piston is partitioned in the cylinder and positioned on the other side in the sliding direction of the piston, and the internal pressure is used as the urging force in the closing direction of the valve body. An operation chamber acting on the piston,
When performing a load operation, the pressure inside the operation chamber is lowered without leading the compressed air on the discharge side of the compressor body to the operation chamber, thereby causing the valve body to operate in the opening direction together with the piston. When the valve seat is opened and the operation is switched from the load operation to the no-load operation, the compressed air on the discharge side of the compressor body is led to the operation chamber to increase the pressure in the operation chamber, thereby the valve body together with the piston. In the air compressor that closes the valve seat by operating in the closing direction,
When performing a load operation, the spring chamber communicates with the primary chamber or a region under almost atmospheric pressure, and when switching from a load operation to a no-load operation, the spring chamber communicates with the secondary chamber, An air compressor comprising spring chamber pressure control means for controlling the pressure of the air chamber.   2. The air compressor according to claim 1, wherein the spring chamber pressure control means communicates the spring chamber with the primary chamber or a region under substantially atmospheric pressure when a load operation is performed, so that the pressure in the spring chamber is reduced. When controlling to be almost atmospheric pressure and switching from load operation to no-load operation, the spring chamber is communicated with the secondary chamber, and the pressure in the spring chamber is controlled to be almost a vacuum pressure. Features an air compressor.   3. The air compressor according to claim 1, wherein the spring chamber pressure control means includes a first control path that communicates with the primary chamber or a region under substantially atmospheric pressure, and a second control channel that communicates with the secondary chamber. A control path, a third control path that communicates with the spring chamber, and a three-way that communicates with the third control path by selecting one of the first control path and the second control path When the valve is in a load operation, the three-way valve is controlled so that the first control path and the third control path are communicated, and the second control is performed when switching from a load operation to a no-load operation. An air compressor comprising: a control device that controls the three-way valve so as to communicate a path with the third control path.   4. The air compressor according to claim 3, wherein the spring chamber pressure control means includes a check valve that is provided in the second control path and prevents a back flow from the secondary chamber to the spring chamber. And air compressor.   5. The air compressor according to claim 1, wherein the air compressor is branched and connected to a discharge path of the compressor body, and discharges compressed air on a discharge side of the compressor body to the operation chamber. An air release path for discharging to the room or an area under almost atmospheric pressure, and an air release path provided in the air release path, switched to a closed state when performing a load operation and an open state when performing a no load operation An air compressor comprising an air release valve.

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