JP2908613B2 - Intake obstruction type unloader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the flow rate of gas sucked into a working chamber of a compressor body, and controls the operation of the compressor body.
The present invention relates to an intake blockage type unloader that controls full load operation, capacity control operation, and no-load operation.

[0002]

2. Description of the Related Art In an intake blocker type unloader provided on a suction side of a compressor body, a diaphragm is fixed to a rod having an open / close valve for opening and closing a suction port of an unloader housing, and consumption of compressed gas on a consumption side is stopped. When the pressure decreased, the gas pressure was supplied to one side of the diaphragm to move the on-off valve to a position to close the suction port, and when the consumption of the compressed gas on the consumption side was restarted or increased, the gas was supplied to the diaphragm. In general, the on-off valve is moved to a position where the suction port is opened by releasing gas pressure. This method was intended to stop the compression of new gas when the consumption of compressed gas on the consuming side stopped or decreased, and at the same time to reduce power consumption. Required additional equipment such as special equipment. Therefore, between the full-load operation in which the compressor body is operated with the opening port of the unloader fully opened and the no-load operation in which the compressor body is operated with the suction port of the unloader fully closed. In addition, a pipe system communicating with a discharge port of the compressor body enables a capacity control operation in which an on-off valve continuously controls an effective area of a suction port of an unloader in accordance with an increase or a decrease in consumption of compressed gas on a consumption side. A compressor capacity control method has been proposed which enables the power for driving the compressor body to be kept within the rated output of the driving motor after the pressure of the compressor exceeds a predetermined set value (Japanese Patent Laid-Open No. Hei 3 (1994) -334). 121291). In this proposal, a diaphragm or a piston fixed to a rod of the on-off valve is provided with a diaphragm or a piston fixed to a rod of the on-off valve in order to provide an on-off valve for opening and closing a suction port of an unloader housing with a movement amount in proportion to a pressure increase in a consumption pipe of the compressor body. By supplying the pressure in the consuming pipe or a pressure proportional thereto, the on-off valve is given a movement in the direction of fully closing the suction port, while a single coil spring is provided in a direction against the movement of the on-off valve. Of elasticity.

[0003]

SUMMARY OF THE INVENTION A compressor having an unloader according to the above proposal has a pressure change in a piping system communicating with a discharge port of the compressor, that is, a change in the amount of consumption of gas compressed by the compressor. Thus, the compressor is controlled to one of a full load operation, a capacity control operation, and a no-load operation, and particularly in the capacity control operation, the suction port formed in the unloader housing by the open / close valve in the unloader is steplessly reduced. Since the suction gas amount can be controlled steplessly, the discharge pressure of the compressor is increased while the driving power of the compressor is kept constant, and the capacity of the suction gas is reduced by reducing the suction gas amount from the suction port. It is possible to control the driving force of the compressor during capacity operation within the rated output of the driving motor, and to control the pressure discharged from the compressor into the discharge side piping system of the compressor. When provided with a receiver tank for reserving the gas has an advantage of reducing the capacitance of the receiver tank. As described above, if the discharge pressure of the compressor main body 1 is increased while the power of the driving motor is kept constant during the capacity control operation of the compressor main body 1, control can be performed to reduce the amount of gas suctioned from the suction port 32. Thus, the power efficiency of the compressor becomes extremely good. To achieve this, during the displacement control operation, it is necessary to decrease the intake gas amount in linear proportion to the discharge pressure of the compressor body 1. However, the piston 34 due to the pressure supplied to the control pressure chamber 38 of the unloader 3
There are two types of forces that resist movement. One of them is
When the compressor body 1 is operating at full load, the on-off valve 33 is connected to the suction port 32.
This is the elasticity of the spring 36 (37) for positioning the spring 36 at the fully open position (first position). The elasticity of the spring 36 (37) balances the pressure supplied to the control pressure chamber 38 during the displacement control operation to determine the positions of the piston 34 and the on-off valve 33.
Is set, the pressure is applied to the control pressure chamber 38 even when the compressor main body 1 is supplied with pressure to the control pressure chamber 38 to shift from the full load operation to the capacity control operation. 37) Until the initial set load is exceeded
The on-off valve 33 does not move. The other is that as the on-off valve 33 approaches the fully closed position (second position), the amount of gas suctioned from the suction port 32 decreases, and thus the suction passage communicating with the suction side of the compressor body 1. 12, a pressure acting on the surface of the on-off valve 33 on the side of the suction port 32 is applied to the on-off valve 32.
Is greater than the pressure acting on the suction passage 12 side, and is a negative pressure acting force that pushes the piston 34 back to the fully open position side. The negative pressure acts on the piston 34 when the on-off valve 33 is near the second position. Hereinafter, the sum of the negative pressure acting force and the elastic force of the spring 36 (37) is referred to as a reaction force acting on the piston.

[0004] The present inventors conducted the following experiment in order to examine the effect of the reaction force acting on the piston on the amount of intake gas. The air pressure in the receiver tank 7 exceeded 7.1 kgf / cm 2 (first set value) using the air compressor body having a rated discharge pressure of 7.0 kgf / cm 2 and the control system shown in FIG. At this time, the regulator valve 40 is opened, and the compressed air decompressed by the orifice 28 is supplied to the control pressure chamber 38 of the unloader 3. The piston 34 fixed to the on-off valve 33 via a rod is pressed by the pressure supplied to the control pressure chamber 38 against the elasticity of the spring 36 (37) so that the on-off valve 33 fully opens the suction port 32 (first position). Position of)
To move the compressor main body 1 from the full load operation to the displacement control operation. During the capacity control operation, when the pressure switch PS detects that the pressure in the receiver tank 7 exceeds 8.0 kgf / cm2 (second set value), the valve body 27 of the three-way switching valve 26 is moved from the position A. Switching to the position B, the pressure in the receiver tank 7 is supplied to the control pressure chamber 38 of the unloader 3, the opening / closing valve 33 is moved to the second position, and the operation is shifted from the capacity control operation to the no-load operation. Here, the second
(A fully closed position) refers to the position of the on-off valve 33 where the on-off valve 33 completely closes the suction port 32 and completely shuts off the suction of air into the compressor body 1, and the first position The (full open position) refers to the first position where the on-off valve 33 moves from the second position and gradually increases the amount of air passing through the suction port 32 to maximize the amount of air. It is stopped at this position. The piston movement amount is a percentage of the movement amount of the piston 34 that moves integrally with the on-off valve 33 during the movement from the first position to the second position. It represents the percentage of the amount of air passing through the port 32 to the amount of air passing when the suction port 32 is fully opened.

FIG. 4 shows the relationship between the amount of movement of the piston and the reaction force acting on the piston. The negative pressure acting force is shown in FIG.
As shown by a two-dot chain line I, the maximum value is at the fully closed position (second position) of the on-off valve 33 and zero at the fully open position (first position) of the on-off valve 33. The negative pressure acting force increases at a small ratio during a movement of approximately 70% from the fully opened position of the on-off valve 33 with respect to a total movement amount of the piston 34, and thereafter, the negative pressure acting until approximately 80%. The force increases at a slightly higher rate, and when it exceeds 80%, the force increases at a higher rate until the on-off valve 33 is fully closed. When the elasticity of the spring is converted into a unit of pressure and shown in FIG. 4, when one coil spring is provided on the piston 34 as in the prior art, the reaction force of the spring is shown by a three-dot chain line II. Thus, the valve has an initial load at the fully open position (first position) of the on-off valve,
The reaction force increases linearly with the movement of the piston (compression of the spring). The sum of the negative pressure acting force and the reaction force of the spring is the reaction force indicated by the broken line III. Piston 3
4 shows an example of the result of examining the relationship between the pressure in the receiver tank and the ratio of the intake air amount by attaching the unloader 3 on which the reaction force shown by the line III described above acts to the experimental compressor body 1. And the line VI shown by the broken line in FIG. In line VI in FIG. 5, although the pressure in the receiver tank 7 exceeds the first set value of 7.1 kgf / cm ² and the capacity control is started, the intake gas amount ratio is maintained at 100%. The reason is that the initial load of the spring is large,
When the pressure in the receiver tank reaches 8.0 kgf / cm ² , which is the second set value for instructing no-load operation, the intake gas amount ratio falls below 75% because the initial load of the spring is limited. Therefore, it is considered that a sufficient reaction force cannot be generated when the piston movement amount becomes large. Further, according to the experiments of the present inventors, as shown by the line I in FIG. 4, the movement amount of the piston increases at a small rate at about 70%, and increases at a large rate at about 80% or more. However, it is difficult to reduce the amount of intake gas in linear proportion to the increase in the discharge pressure of the compressor body, and the piston movement amount corresponds to 75 to 80% of the intake gas amount ratio. The rated discharge force used is 7.0 kgf / c
In the compressor of m ^2, 8.0k said second set value
In the range of a small pressure difference of gf / cm ² , the intake gas ratio is reduced in linear proportion to the increase of the discharge pressure of the compressor body until the second set value is reached during the displacement control operation. I found that I can do it. Therefore, the present invention provides that at least the suction gas amount ratio is 75% during the capacity control operation of the compressor body.
Provided is an intake blockage type unloader in which an on-off valve is steplessly moved with respect to a suction port so that a suction gas amount ratio can be reduced at a substantially constant ratio while the pressure decreases to about 80%. The purpose is to:

[0006]

SUMMARY OF THE INVENTION The present invention relates to a diaphragm disposed on a suction side of a compression working chamber of a compressor body and moved in response to a gas pressure introduced into a control pressure chamber formed in a housing. Or, it is movable between a moving body such as a piston, a first position connected to the moving body and fully opening a suction port formed in the housing, and a second position for fully closing the suction port. And a biasing means for biasing the moving body in a direction opposite to a direction in which the gas pressure introduced into the control pressure chamber acts on the moving body. An intake blockage type unloader for controlling an amount of gas sucked into a compression working chamber of a compressor body, which is disposed on a discharge side of the compression working chamber of the compressor body and connected to a check valve and a discharge pipe. A receiver tank, the receiver tank and the housing A first regulator valve and a three-way switching valve for releasing the fluid passage by the pressure of the gas passing through the fluid passage in the gas passage connecting the control pressure chamber formed in the valve and the three-way switching valve; A second regulator valve for releasing the fluid passage by the pressure of gas flowing through the fluid passage to a gas passage connecting the suction passage provided on the suction side of the compression working chamber of the compressor body, and a predetermined flow; An orifice having a fixed fluid passage having a passage area is provided in parallel, and the pressure in a receiver tank disposed on the discharge side of the compression working chamber of the compressor body is lower than a first set value. The three-way switching valve connects the three-way switching valve between a first regulator valve and a suction passage provided on a suction side of a compression working chamber of the compressor, and is connected to a discharge side of the compression working chamber of the compressor body. Installed receiver tongue When the internal pressure exceeds a second set value higher than the first set value, the three-way switching valve forms the three-way switching valve in parallel with the first regulator valve in the housing of the compressor body. The biasing means comprises at least two springs and a rigid collar arranged between the adjacent ends of the springs to move the movable body. When the pressure in the receiver tank is detected to be lower than a first set value, the three-way switching valve sets the three-way switching valve to the direction described above. The three-way switching valve is connected to a suction passage provided on the suction side of the compressor body and detects that the pressure in the receiver tank exceeds a second set value. Formed in the housing of the compressor body The moving body is moved to a second position where the suction port is fully closed by connecting to the control pressure chamber. Further, in the present invention, the moving body is
A piston, which divides a cylinder chamber formed between the end wall and the support wall of the housing into the control pressure chamber and the secondary pressure chamber, is formed by a rod slidably supported by the support wall. Another feature is that the collar and the spring are coaxially arranged on the rod in the secondary pressure chamber while being connected to the on-off valve.

[0007]

FIG. 1 is a sectional view of an embodiment of an intake obstruction type unloader according to the present invention, and FIG. 2 is an example in which the intake obstruction type unloader of the present invention is mounted on a screw air compressor to perform capacity control. FIG. 3 is a sectional view of the regulator valve. In FIG. 2, an unloader 3 of an intake blockage type is mounted on the suction side of the compression working chamber 2 of the screw-type rotary compressor main body 1, and the discharge chamber 4 on the discharge side of the compression working chamber 2 is provided with a check valve 5 and a check valve 5. It is connected to a receiver tank 7 through a discharge pipe 6, and a consumption-side air pipe 11 is connected to a compressed air outlet 8 of the receiver tank 7 through an on-off valve 9 and a check valve 10. The unloader 3 includes a housing 31 as shown in FIG. 1, and a piston 34 is fixed to an opening / closing valve 33 for opening / closing a suction port 32 for sucking air through the housing 31 through an air filter (not shown). On one axial side of a cylinder chamber provided with a cylinder liner 35 that slidably supports the piston 34, the opening / closing valve 33 is separated from the suction port 32 to increase the opening area of the suction port 32. Two springs 36 and 37 for urging the piston 34
And a control pressure chamber 38 is formed on the other side of the piston 34 in the axial direction. The cylinder chamber accommodating the springs 36 and 37 communicates through an opening 39 with a passage that forms part of the intake passage 12 to the compression working chamber 2 of the compressor body 1. More specifically, the cylinder chamber provided with the cylinder liner 35 is closed at one axial end by an end wall 51 and at the other end by a support wall 52 of the housing 31.
And the end wall 51, and the cylinder chamber so as to form the control chamber 38 and the secondary chamber 85 between the piston 34 and the support wall 52. The piston 34 and the on-off valve 33 are provided with rods 53 coaxially arranged on both.
The rod 53 is slidably supported in the axial direction on the support wall 52 via a sleeve bearing. In the rod 53, a collar 86 formed by concentrically forming two annular seats 54, 55 with a rigid plate-like material through a central hole 56 concentric with the annular seats 54, 55. The first spring 36 is interposed between the piston 34 and the first annular seat 54 located on the outer periphery of the collar 86 so as to be freely movable in the axial direction. The second spring 37 is interposed between the second annular seat portion 55 located at the center position and a spring receiving portion 57 formed on the periphery of the collar support portion of the support wall 52. The first spring 36 has a smaller spring constant than the second spring 37.

When a male rotor 13 of the compressor body 1 is driven to rotate by a prime mover (not shown), the male rotor 13 is unloaded via a suction passage 12 together with a female rotor (not shown) meshing with the rotor 13. 3 is compressed in the compression working chamber 2 and discharged to the discharge chamber 4. The discharged compressed air is discharged into the receiver tank 7 through the check valve 5 and the discharge pipe 6. Oil for lubricating the male and female rotors and cooling the compressor body 1 is sent to the compression working chamber 2 via the oil supply pipe 14, the cooler 15, and the oil amount adjusting valve 16 by using the pressure in the receiver tank 7. The oil is discharged into the discharge chamber 4 together with the compressed air, sucked into the pump 17 from the lowest level of the discharge chamber 4 as a gas-liquid mixed fluid, and collected in the receiver tank 7 through the pipe 18 and the discharge pipe 6. It is separated from the compressed air in 7.

The other end of the first gas passage 21 formed of a pipe having one end connected to the air outlet 8 of the receiver tank 7 is connected to the inlet side 41 of the first regulator valve 40, The other end of the second gas passage 22 formed of a pipe formed in the end wall 51 of the housing 31 and having one end communicating with the opening 30 communicating with the control pressure chamber 38 is connected to the outlet side of the first regulator valve 40. 42. As shown in FIG. 3, the first regulator valve 40 has a valve seat 44 formed in a fluid passage 43 that communicates the inlet side 41 and the outlet side 42, and a valve body 45 seated on the valve seat 44 is Inside the housing of the regulator valve 40, the peripheral edge is fixed to a diaphragm 46 fixed by the housing, and a pressure existing on the inlet side 41 from the inlet side 41 through the passage 47 is applied to one surface of the diaphragm 46, On the other surface of the diaphragm 46, elasticity of a spring 48 is urged in a direction against the pressure,
The elasticity of the spring 48 is adjustable by a screw rod 49 screwed into the housing. Accordingly, the air outlet 8 of the receiver tank 7 reaches the first regulator valve 40 via the first gas passage 21, and is supplied from the inlet side 41 of the receiver tank 7 to the diaphragm 48 via the passage 47. When the air pressure becomes larger than the urging force of the spring 48, the valve body 45 separates from the valve seat 44 to open the fluid passage 43, and reduces the pressure in the first gas passage 21 to the second gas passage 22, Orifice 2 provided in passage 22
8. The pressure is supplied to the control pressure chamber 38 through the opening 30 formed in the end wall 51 of the housing 31 of the unloader 3. In this control device, the air pressure (first set value) for opening the fluid passage 43 of the first regulator valve 40 is 7.1 kg.
The elasticity of the spring 48 adjusted by the screw rod 49 is determined in advance so as to be f / cm ² .

A branch passage 2 branched from between the air outlet 8 of the first gas passage 21 and the first regulator valve 40.
4. A branch passage 25 branching between the orifice 28 of the second gas passage 22 and the unloader 3 and a housing 31 of the unloader 3 and suction from the suction port 32 to the working chamber 2 side of the compressor body 1 through the suction port 32. A third pipe made of one end connected to an opening 19 connected to the passage 12;
Is connected to an electromagnetic three-way switching valve 26. While the switching valve 26 is energized, the first position for connecting the branch passage 25 of the second gas passage 22 to the third gas passage 23 when the portion A of the valve body 27 is in the communication position. And when de-energized, the portion B of the valve body 27 is in the communicating position, and the branch 25 of the second gas passage 22 communicates with the branch 24 of the first gas passage 21. It is in position 2. A second regulator valve 50 and an orifice 29 having a fixed fluid passage having a predetermined flow area are connected in parallel to the third gas passage 23. The second regulator valve 50 has the same configuration as the first regulator valve 40. Therefore, the reference numerals 41 to 49 used for the description hereinafter refer to the same parts as the reference numeral 41 to 49 of the first regulator valve 40, respectively. When the valve body 27 of the switching valve 26 is at the first position for positioning the portion A at the communication position, when the first regulator valve 40 opens the fluid passage 43, the outlet side 42 of the regulator valve 40 is opened. From the second gas passage 2
2. The compressed air supplied to the third gas passage 23 through the orifice 28, the branch passage 25, and the portion A of the valve body 27 passes through only the orifice 29 and the opening 19 through the compressor body while the pressure is low. The air is introduced into one suction passage 12. Next, when the pressure in the receiver tank 7 increases and the force applied to the diaphragm 46 by the air pressure supplied to the second regulator valve 50 becomes greater than the elasticity of the spring 48,
The second regulator valve 50 opens the fluid passage 43.
At this time, the compressed air that has passed through the orifice 29 and the second regulator valve 50 is both introduced into the suction passage 12 of the compressor body 1 through the opening 19. In this control device, the air pressure (intermediate set value) for opening the fluid passage 43 of the second regulator valve 50 is set to approximately 0.7 kgf / cm ^2.
The spring 4 adjusted by the screw 49 so that
The elasticity of 8 is determined in advance.

The pressure of the compressed air stored in the receiver tank 7 is detected, and when the pressure exceeds a predetermined value from the first set value (7.1 kgf / cm ² ), the circuit is opened and detected. A pressure switch PS that closes when the pressure falls below the first set value due to a decrease in pressure is provided in the receiver tank 7, and the pressure switch PS is connected to the electromagnetic three-way switching valve 26. As a result, the switching valve 26 keeps the valve 2 until the pressure in the receiver tank 7 reaches a predetermined value.
7 is in a first position for placing the portion A in the communicating position,
Is connected to the third gas passage 23, and when the pressure in the receiver tank 7 exceeds the predetermined value, the valve body 27 is switched to the second position where the part B is placed in the communication position. , The second gas passage 22 is connected to the first gas passage 21.
When the pressure in the receiver tank 7 falls below the first set value from this state, the valve body 27 is returned to the first position. In the present embodiment, a predetermined value (second set value) of the pressure detected by the pressure switch PS is set to 8.0 kgf / cm ² in advance.

In the present control device, the discharge of the compressor body 1 when the on-off valve 33 of the unloader 3 has the suction port 32 completely opened and the compressor body 1 is operated at full load by the prime mover. Air pressure is 7kgf / cm
^{Assume 2} . When the compressor body 1 is in the full load operation state,
When the amount of compressed air taken out from the receiver tank 7 to the consumption-side air pipe 11 decreases, the air pressure in the receiver tank 7 gradually increases. When the air pressure exceeds a predetermined first set value of 7.1 kgf / cm ² set in the first regulator valve 40, the fluid passage 43 of the first regulator valve 40 is opened. Since the first set value is lower than the predetermined second set value of 8.0 kgf / cm ^2, which is set in the pressure switch PS, the valve body 27 of the switching valve 26 places the portion A at the communicating position. The compressed air which has been passed through the fluid passage 43 of the first regulator valve 40 and is supplied to the control pressure chamber 38 of the unloader 3 through the second gas passage 22 to apply the pressure to one surface of the piston 34 and A part of the compressed air supplied to the second gas passage 22 is introduced into the suction passage 12 of the compressor body 1 through the switching valve 26, the third gas passage 23 and the opening 19. The air pressure supplied to the third gas passage 23 is
While the reduced air pressure is lower than 0.7 kgf / cm ² which is a predetermined intermediate set value set in the second regulator valve 50. The fluid is introduced into the suction passage 12 of the compressor body 1 through the orifice 29 without opening the fluid passage 43 of the second regulator valve 50. The piston 34 moves in a direction approaching the suction port 32 against the urging force of the springs 36 and 37 by the air pressure supplied to the control pressure chamber 38, and the opening area of the suction port 32 is changed by the on-off valve 33. Suction passage 12 of compressor body 1
Starts capacity control to limit the flow rate of intake air to the engine. Thereafter, stepless capacity control is performed with an increase in the pressure in the first gas passage 21.

If the consumption of the compressed air taken out from the consumption-side air pipe 11 is still small, the pressure in the receiver tank 7 rises and the first gas passage 21 passes through the branch passage 25 of the second gas passage 22. When the compressed air pressure supplied to the third gas passage 23 also gradually rises and exceeds a predetermined intermediate set value of 0.7 kgf / cm 2 set in the second regulator valve 50, the second regulator valve 50
Is opened, and the suction passage 12 of the compressor body 1 is opened.
The compressed air passing through the orifice 29 and the compressed air passing through the fluid passage 43 of the second regulator valve 50 are introduced from the opening 19 in parallel. When the unloader 3 starts the stepless displacement control, the first and second springs 36 and 37 that urge the open / close valve 33 in the opening direction are compressed. Among the two springs 36, 37, the large-diameter first spring 36 has a smaller spring constant than the small-diameter second spring 37, the first spring 36 bends more than the second spring 37, and the two springs 36, 37 The second spring 37 is largely bent after the collar 86 which locks the piston 34 contacts the piston 34. On the other hand, when the gas pressure in the second gas passage 22 rises, the moving speed of the piston 34 also increases, but when the fluid passage 43 of the second regulator valve 50 is opened, the third passage 23 and the opening 1 are opened.
9, the amount of compressed air introduced into the suction passage 12 of the compressor body 1 increases, and therefore, the moving speed of the on-off valve 33 does not increase so much regardless of the rise in the second gas passage 22. Rather, it slows down. In the present control device, the pressure in the second gas passage 22 is set to the intermediate set value (0.7 kgf / cm
When the pressure reaches the second set value (8.0 kgf) after the second regulator valve 50 starts to operate after reaching 2).
/ Cm2), the pressure in the control pressure chamber 38 of the unloader 3 is suppressed to about 1.0 kgf / cm2 (0.7 to 1.3 kgf / cm2). When the pressure in the receiver tank 7 exceeds the second predetermined value of 8.0 kgf / cm 2, the pressure switch PS detects this and demagnetizes the electromagnetic three-way switching valve 26, and the valve body 27. Is switched to the second position where the circulation position is the part B. Accordingly, the second gas passage 22 communicates with the first gas passage 21 through the branch passage 25, and
Of the control pressure chamber 38 of the unloader 3
And the supply of the pressurized air to the third gas passage 23 is cut off. This ensures that the piston 34 immediately seats the on-off valve 33 in the fully closed position of the suction port 32,
The operation shifts to the no-load operation of the compressor body 1. In the embodiment shown in FIG. 1, the piston 34 fixed to the valve rod of the on-off valve 33 has been described as the on-off valve moving means for moving the on-off valve 33 with respect to the suction port 32. Even if the diaphragm fixed to the housing 31 is used, it is possible to obtain an air intake closing type unloader having the same operation. The third gas passage 23
Is connected to the suction passage 12 instead of the housing 31.
The same effect can be obtained by communicating with the secondary chamber 85.

The reaction force acting on the piston in the embodiment of the intake closing type unloader shown in FIG. 1 will be examined. In FIG. 4, the negative pressure acting force indicated by the line I is the same as the negative pressure acting force measured by the experiment. In the above-described embodiment, the first and second springs 36 and 37, which are coil springs, are connected to the first end of the collar 86 by the adjacent ends.
And the second annular seats 54 and 55 are arranged so that the direction of action of the elasticity is parallel to the direction of movement of the collar 53 and in series with each other. When the spring constant is smaller than the spring constant of the second spring 37, the first spring 36 first bends upon movement of the piston 34, and the second spring 37 bends after the collar 86 contacts the piston 34. When the elasticity of the first and second springs 36 and 37 is converted into a pressure value, the elasticity is represented by a broken line as shown by a dashed line IV in FIG. The reaction force obtained by combining the pressures of the line I and the line IV is as shown by the line V shown by the solid line. For comparison with the prior art, at a position of 75% of the piston movement amount (the reaction force acting on the piston is equivalent to 1.2 kgf / cm2),
The reaction force acting on the piston in the prior art shown by the broken line III and the reaction force acting on the piston in the present embodiment shown by the solid line V have the same value. Comparing the two, the reaction force acting on the piston in this embodiment is:
The reaction force in the prior art is smaller than the reaction force in the prior art from the movement start position of the piston (the fully open position of the on-off valve) to the position of 75% of the piston movement amount. Until), the reaction force acting on the piston in this embodiment is larger than the reaction force in the prior art. When the unloader 3 of the present embodiment, in which the reaction force indicated by the line V acts on the piston 34, is attached to the experimental compressor body 1, and the relationship between the pressure in the receiver tank and the ratio of the amount of intake gas is examined, FIG. Line VIII shown by a solid line
It is as follows. In this embodiment, the spring constant of the first spring 36 can be selected to be smaller than that of the prior art.
The pressure in the receiver tank 7 is equal to the first set value (7.1 kg).
f / cm 2), the intake gas amount ratio starts to decrease at a lower receiver tank pressure than in the prior art. Also, the spring constant of the second spring 37 is determined so that the reaction force acting on the piston becomes equal to the reaction force in the related art at the position of 75% of the piston movement amount, so that the pressure in the receiver tank becomes the second. Set value (8.
The intake gas amount ratio when it reaches 0 kgf / cm 2) is larger than the intake gas amount ratio in the prior art, and shows 75%.

In FIG. 5, a point M where the pressure inside the receiver tank is the first set value (7.1 kgf / cm 2) and the intake gas amount ratio is 100%, and the pressure inside the receiver is the second set value Value (8.0 kgf / cm2) and the intake gas amount ratio is 75
%, A line VII (indicated by a dashed line) connecting the point N is drawn. The line VII is linearly proportional to the discharge pressure of the compressor body during the capacity control operation of the compressor. , And corresponds to a line indicating control for making the power efficiency of the compressor extremely good. The line VIII indicating the ratio of the amount of intake gas in the present embodiment indicates that the initial load for holding the piston at its movement start position is small due to the small spring constant of the first spring 36, and accordingly the first setting. At the value, the control of the intake gas amount ratio is started early after the shift to the displacement control operation of the compressor body 1, and the intake gas amount ratio decreases linearly up to 75% of the piston movement amount as shown in FIG. Thus, it is clear that control along the ideal line VII can be performed. The relationship between the pressure in the receiver tank and the pressure in the control pressure chamber in this embodiment is as shown in FIG. In this embodiment, the spring constant of the first spring 36 is set smaller than the spring constant of the second spring 37. However, in the present invention, the spring constant of the second spring 37 is set to the first constant. When the on-off valve 33 is moved from the first position to the second position, the second spring 37 is first largely bent, and after the collar 86 abuts against the support wall 52, the spring It is obvious that the same effect can be obtained even if one spring 36 is bent. Further, in the present embodiment, when the spring constants of the first and second springs 36 and 37 are made equal to each other and those having different lengths are used,
When these springs gradually bend against the pressure in the control pressure chamber 38, before the shorter length of the spring is fully bent, the annular seat 54 or 55 on which the spring is seated is first moved to the secondary chamber side. End wall or support wall 52 of the piston 34
The same effect can be obtained by contacting the end wall of the piston 34 and then moving the piston 34 by bending of the other spring. That is, both springs are in series until one of the annular seats contacts the end wall,
This is because the spring constant is reduced, and then the spring constant is increased after the annular seat comes into contact. Further, according to the above embodiment, one or more springs having a spring constant intermediate between the values of the spring constants of the first and second springs 36 and 37 are replaced with the first and second springs 3.
By arranging the lenses in series with 6, 37 via a collar,
It is very apparent that the control can be performed in such a manner that the line VIII is more closely aligned with the ideal control line VII.

[0016]

The present invention relates to a moving body such as a diaphragm or a piston which is disposed on the suction side of a compressor body and moves in response to a gas pressure introduced into a control pressure chamber formed in a housing. An on-off valve movably connected between a first position connected to the moving body and fully opening a suction port formed in the housing, and a second position for fully closing the suction port; Biasing means for biasing the moving body in a direction opposite to a direction in which the gas pressure introduced into the control pressure chamber acts on the moving body, and a compression operation of the compressor body by movement of the on-off valve. With the intake block type unloader for controlling the amount of gas sucked into the chamber, while no pressure is supplied to the control pressure chamber of the compressor body, the moving body closes the on-off valve by the urging means. 1 to bring the compressor body into full load operation, When gas pressure is supplied to the control pressure chamber, the moving body is moved against the urging force by the magnitude of the gas pressure, and the on-off valve is moved from the first position to the second position. And the amount of gas sucked into the compression working chamber of the compressor main body from the suction port is controlled by the relative position of the on-off valve and the suction port to bring the compressor main body into a capacity control operation state. An unloader that functions to completely block the suction port when reaching the second position and to reduce the amount of gas sucked into the compression working chamber of the compressor body from the suction port to zero. In the present invention, at least two springs having different spring constants are used as the urging means, and a color having a high rigidity is brought into contact between adjacent ends of the springs, so that the moving body Since the action direction of the elasticity of the spring is arranged in series in the moving direction of the spring, when the gas pressure is supplied to the control pressure chamber and the compressor body is shifted from the full load operation state to the capacity control operation state, When the on-off valve is moved from the first position to the second position by the flexure of the plurality of springs, the on-off valve is moved to a magnitude corresponding to the gas pressure supplied to the control pressure chamber. As an urging means for providing a reaction force to be positioned at a position corresponding to the position, the initial load of the urging means for holding the on-off valve at the first position (a position where the suction port is fully opened) can be reduced. And therefore the control pressure It can be the gas pressure to be supplied to start the movement of the on-off valve between a relatively low.

According to the present invention, as the urging means, at least a second spring other than the first spring is connected in series with the direction of action of the elasticity of the first spring. Since the collar is disposed so as to be in contact with between the end portions, the spring constant of the first spring can be reduced by appropriately setting the spring constant of the second spring. Regardless, the on-off valve is
At the time when the position reaches the position, the elasticity for holding the position of the on-off valve against the gas pressure supplied to the control pressure chamber as the urging means as a whole can be secured, and the capacity control operation state of the compressor body In this case, the ratio of the amount of gas sucked into the compression working chamber of the compressor body from the suction port to the suction gas amount in a state where the on-off valve fully opens the suction port is linearly proportional to the discharge pressure of the compressor body. And the moving speed of the on-off valve 33 can be slowed down immediately before the on-off valve 33 closes the suction port 32, and the rapid closing can be suppressed. There is an effect that the efficiency can be made extremely good. This allows
A first set value for shifting the compressor body from the full load motion state to the capacity control operation state compared to the rated discharge pressure of the compressor body, and a shift of the compressor body from the capacity control operation state to the no load operation state Even if the pressure difference between the second set value and the second set value is small compared to the first set value, the capacity of the receiver tank provided on the discharge side of the compressor body is equal to the rated value of the compressor body. Even if the discharge capacity is small, the frequent operation of the unloader on-off valve is prevented through all the operating states of the compressor body to increase the durability of the on-off valve, and the compressor consumption side Thus, even if there is a sudden change in the consumption of the compressed gas, an excellent effect of preventing the discharge pressure of the compressor from dropping is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of an intake blockage type unloader according to the present invention.

FIG. 2 is a piping diagram for controlling the capacity of a compressor by the unloader of the present invention.

FIG. 3 is a cross-sectional view of a regulator valve.

FIG. 4 is a diagram showing a relationship between a piston movement amount and a reaction force acting on the piston.

FIG. 5 is a diagram showing the relationship between the pressure in the receiver tank and the ratio of the amount of intake gas.

FIG. 6 is a diagram showing a relationship between a piston movement amount and an intake gas amount ratio.

FIG. 7 is a diagram showing a relationship between a pressure in a receiver tank and a pressure in a control pressure chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor main body 2 Working chamber 3 Unloader 7 Receiver tank 31 Housing 32 Suction port 33 Opening / closing valve 34 Piston 36, 37 Spring 38 Control pressure chamber 51 End wall 52 Support wall 53 Rod 85 Secondary chamber 86 Color

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F04C 23/00-29/10 F04C 18/16 F04B 39/10 F16K 31/12

Claims (2)

(57) [Claims] A moving body such as a diaphragm or a piston, which is disposed on a suction side of a compression working chamber of a compressor body and moves in response to a gas pressure introduced into a control pressure chamber formed in a housing; An on-off valve movably connected between a first position that is connected to the moving body and fully opens a suction port formed in the housing, and a second position that fully closes the suction port; Urging means for urging the moving body in a direction opposite to a direction in which the gas pressure introduced into the pressure chamber acts on the moving body, and the compression operating chamber of the compressor body is moved by moving the on-off valve. An intake blocker type unloader for controlling an amount of gas to be sucked, comprising: a receiver tank disposed on a discharge side of a compression working chamber of a compressor body and connected via a check valve and a discharge pipe; and Control pressure chamber formed in the housing A first regulator valve and a three-way switching valve for releasing the fluid passage by the pressure of the gas passing through the fluid passage in the gas passage connecting between the three-way switching valve and the compression working chamber of the compressor body; A second regulator valve for releasing the fluid passage by the pressure of the gas flowing through the fluid passage to the gas passage connecting the suction passage provided on the suction side and a fixed fluid passage having a predetermined passage area. An orifice provided in parallel with the three-way switching valve when a pressure in a receiver tank disposed on a discharge side of a compression working chamber of the compressor body is lower than a first set value. The first
Between the regulator valve and a suction passage provided on the suction side of the compression working chamber of the compressor, and the pressure in the receiver tank disposed on the discharge side of the compression working chamber of the compressor body is increased by the When a second set value higher than the set value of 1 is exceeded, the three-way switching valve is connected to the control pressure chamber formed in the housing of the compressor body in parallel with the first regulator valve. The biasing means is configured to apply at least two springs and a rigid collar arranged in contact between adjacent ends of the springs with an elastic force in a moving direction of the moving body. If the pressure in the receiver tank is detected to be lower than a first set value by arranging the three-way switching valve in series with each other, Connected to the suction passage provided on the side When detecting that the pressure in the receiver tank exceeds a second set value, the three-way switching valve connects the three-way switching valve to a control pressure chamber formed in a housing of the compressor body. At least at least the moving body is moved to a second position where the suction port is fully closed. 2. The moving body is a piston that divides a cylinder chamber formed between an end wall and a support wall of the housing into a control pressure chamber and a secondary chamber, and the on-off valve is provided with the on-off valve. 2. An air intake according to claim 1, wherein said piston is connected to said piston by a rod slidably supported on a support wall, and said collar and spring are coaxially disposed in said secondary chamber in said secondary chamber. Closed type unloader.