JP2001254691A - Screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw compressor simplifying a piping structure, reducing the number of switching valves, simplifying the control, and reducing the manufacturing cost. SOLUTION: In loading up, a slide valve is energized to a loading up side so that oil in one chamber 41 of a driving cylinder 33 is discharged to an oil sump through an oil line 42 and an oil switching valve SV2. In loading down, while the oil 41 is fed to one chamber 41 of the driving cylinder 33 through a check valve 44, gas is exhausted from the other chamber 47 to a low-pressure side through an exhaust line 48 and a gas switching valve SV2. The oil line 42 is thus used for the both oil feeding and discharging and no dedicated oil discharge line is provided so that the piping structure and control are simplified and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw compressor used for a refrigerator or the like to compress a refrigerant.

[0002]

2. Description of the Related Art Conventionally, as this type of screw compressor, there is one as shown in FIG. The screw compressor includes a screw rotor 1, a slide valve 2 for controlling a capacity, and a drive cylinder 3 for driving the slide valve 2. The slide valve 2 moves leftward (load-up side) as shown by an arrow X in FIG. 4A due to a pressure difference of the refrigerant acting on both ends (a pressure difference between the high-pressure region H and the low-pressure region L). Being energized.
The slide valve 2 is connected to a piston 5 of a drive cylinder 3 by a connection mechanism 6.

A high-pressure oil reservoir (not shown) is connected to one chamber 11 of the drive cylinder 3 via an oil line 12 so that high-pressure oil is supplied to the chamber 11. Further, the oil on-off valve SV13 is connected to the oil line 12.
And a check valve 14 and a capillary 15 are provided in a line bypassing the oil on-off valve SV13.

On the other hand, the other chamber 17 of the drive cylinder 3
Is connected to a discharge line 18 connected to the low-pressure area L on the suction side, so that gas is discharged from the other chamber 17 to the low-pressure area L. The discharge line 18 is provided with a gas on-off valve SV11.

Further, a line between the oil on-off valve SV13 of the oil line 12 and one chamber 11 of the drive cylinder 3 and a downstream side of the gas on-off valve SV11 of the discharge line 18 are connected to an oil discharge line 21. And this oil drain line 2
1 is connected to an on-off valve SV12 exclusively for oil discharge and a capillary 22. Reference numeral 9 denotes a seal member for sealing between the outer peripheral surface of the piston 5 and the inner peripheral surface of the tube, and reference numeral 13 denotes a seal member for sealing between the piston rod 19 and the inner peripheral surface of the bush 20.

[0006] The screw compressor having the above structure is shown in FIG.
As shown in (B), on-off valves SV11, SV12, SV
By opening and closing 13, operations such as load-up, load-down, and load holding are performed. FIG. 4B
In, ○ indicates open, and × indicates closed.

During the load-up operation, the on-off valve SV12 dedicated to oil discharge is opened, while the other on-off valves SV11 and SV11 are opened.
SV13 is closed. Then, slide valve 2
4A is pressed by the pressure of the refrigerant in the arrow X direction in FIG. 4A, so that the piston 5 of the drive cylinder 3 is also pressed to the left. On the other hand, as shown by an arrow u1, the oil in one chamber 11 of the drive cylinder 3 is part of the oil line 12, the oil discharge line 21, and the oil discharge on-off valve SV.
The gas is discharged to the low pressure region L via the capillary 12 and the capillary 22.

During the load-down operation, the gas on-off valve S
V11 is opened, and the other on-off valves SV12, SV1
3 is closed. Then, as shown by the arrow d1,
Check valve 14, capillary 1 from oil sump (high pressure)
5. While high-pressure oil is supplied to one chamber 11 of the drive cylinder 3 through the oil line 12, gas is discharged from the other chamber 17 of the drive cylinder 3 to the discharge line as shown by the arrow d2. The piston 5 is discharged to the low-pressure region L via the valve 18 and the gas on-off valve SV11, and the piston 5 moves rightward, thereby moving the slide valve 2 rightward.

When the load is held, the gas on-off valve SV11
And the oil on-off valve SV12 are closed, the piston 5 of the drive cylinder 3 is stopped, and the slide valve 2 is stopped.

When stopped, only the on-off valve SV13 is opened, and the piston 5 of the drive cylinder 3 is moved to the left by the spring force of a spring (not shown).

[0011]

However, the above-mentioned conventional screw compressor requires three types of pipes: an oil line 12, a discharge line 18, and a line 21 exclusively for oil discharge, as shown in FIG. , The external piping system P becomes complicated, and the number of piping parts increases accordingly.
There is a problem that the number of assembly steps is increased. Further, when the piping is complicated, the possibility of occurrence of trouble due to the vibration of the piping increases. Furthermore, three on-off valves SV11, SV1
2, control is complicated because SV13 is required.
In addition, there is a problem that the manufacturing cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a screw compressor having a simplified piping structure, reduced piping components, and less likely to cause piping vibration.

Another object of the present invention is to provide a screw compressor in which the number of on-off valves is small, the control is simple, and the manufacturing cost is low.

[0014]

According to a first aspect of the present invention, there is provided a screw compressor including a screw rotor, a slide valve for controlling a displacement, and a drive cylinder for driving the slide valve. In the screw compressor, the slide valve is urged toward the load-up side, and an oil line for supplying or discharging oil to one chamber of the drive cylinder is provided on the oil line. An on-off valve for oil, a check valve in which a flow toward one chamber of the drive cylinder is in a forward direction, a discharge line for discharging gas from the other chamber of the drive cylinder, and a discharge line. And a gas on-off valve.

In the above configuration, at the time of load-up, the oil on-off valve is opened and the gas on-off valve is closed. Then, since the slide valve is urged toward the load-up side, oil in one chamber of the drive cylinder is discharged to, for example, an oil reservoir through an oil line and an oil on-off valve.

On the other hand, when the load is reduced, the gas on-off valve is opened and the oil on-off valve is closed. Then, oil is supplied to one chamber of the drive cylinder through the check valve, and gas is discharged from the other chamber of the drive cylinder to the low pressure side through the discharge line and the gas on-off valve.

As described above, since the oil line is used for both supply and discharge of oil to one chamber of the drive cylinder, and no line dedicated to oil discharge is provided, the piping structure is simplified. In addition, the number of piping parts is reduced and the cost is reduced.
Further, since the piping structure is simple, the risk of piping vibration is reduced.

In addition, since two on-off valves are required, an on-off valve for oil and an on-off valve for gas, control is simple and a screw compressor can be manufactured at low cost.

According to a second aspect of the present invention, there is provided a screw compressor according to the first aspect, wherein the check valve is connected in parallel to an oil on-off valve.

According to the above configuration, the check valve is connected in parallel with the oil on-off valve, so that oil from the tip of the oil line can be supplied to one chamber of the drive cylinder, and the piping structure can be simplified. Become.

According to a third aspect of the present invention, in the screw compressor according to the first or second aspect, a check valve is provided in the oil line so that a flow toward the drive cylinder is an uncontrolled flow. It is characterized in that a flow regulating valve is provided.

According to the above construction, since the flow regulating valve with the check valve is provided so that the flow toward the drive cylinder becomes an uncontrolled flow, the oil is quickly supplied to one chamber of the drive cylinder. The load can be quickly reduced, and the speed at which the load is increased can be adjusted with high accuracy by adjusting the discharge speed of the oil discharged from the one chamber.

According to a fourth aspect of the present invention, there is provided a screw compressor according to any one of the first to third aspects, wherein an oil valve between the oil on-off valve and one chamber of a drive cylinder is provided. A high-pressure line connected to the high-pressure side is connected to the line, and the check valve is provided in the high-pressure line so that a flow toward one chamber of the drive cylinder is in a forward direction.

According to the above configuration, in an emergency or the like, the high-pressure fluid from the high-pressure line is supplied to one chamber of the drive cylinder through the check valve, and quickly and forcibly.
You can load down.

According to a fifth aspect of the present invention, in the screw compressor according to any one of the first to fourth aspects, at least two of the oil line, the discharge line, and the high-pressure line are connected to one another. It is characterized by comprising one manifold.

According to the above configuration, since at least two of the oil line, the discharge line, and the high pressure line are constituted by one manifold, the piping structure is extremely simple and compact. Further, piping vibration can be prevented.

According to a sixth aspect of the present invention, in the screw compressor according to any one of the first to fifth aspects, a notch for setting a minimum partial load operation is provided in a piston rod of the drive cylinder. It is characterized by having been provided.

According to the above construction, in a state in which the notch provided in the piston rod of the drive cylinder overlaps the bush, the inside of the other chamber of the drive cylinder is connected to the high pressure atmosphere on the external discharge side through the notch. That is, since the piston communicates with the high-pressure region, the piston is prevented from moving to the load-down side.
Therefore, a guarantee mechanism for the minimum partial load operation can be easily obtained.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

As shown in FIG. 1A, the screw compressor includes a screw rotor 31, a slide valve 32 for controlling the capacity, and a drive cylinder 33 for driving the slide valve 32.

FIG. 2 shows a specific configuration of the screw compressor. A screw rotor 31 is rotatably fitted to a cylinder 29, and the effective compression amount, that is, the capacity of the screw rotor 31 is determined. A slide valve 32 to be controlled is provided so as to be able to advance and retreat in the axial direction. In the slide valve 32, a high pressure in a high-pressure region (discharge side) H acts on the right end surface, and a low pressure in a low-pressure region (suction side) L acts on the left end surface. , And is biased to the left (load-up side). The slide valve 32 and the piston rod 49 of the drive cylinder 33 are connected by the connection mechanism 36, and the slide valve 32 is moved in the axial direction by the drive cylinder 33 to control the compression start position to control the displacement. Like that. Reference numeral 71 denotes a coil spring that biases the connection mechanism 36 to determine the rest position of the piston 35 of the drive cylinder 33.

On the other hand, the piston 3 of the drive cylinder 32
5, a seal member 39 is provided to seal the outer periphery of the piston 35, but no seal member is provided between the piston rod 49 and the bush portion 65. The piston rod 49 is provided with a notch 43 for setting a minimum partial load. In FIG. 2, the drive cylinder 3
The piping structure connecting the one chamber 41 and the other chamber 47 of FIG. 3 is omitted.

As shown in FIG. 1A, one chamber 41 of the drive cylinder 33 is connected to a high-pressure oil reservoir (not shown) via an oil line 42 for supplying or discharging oil. I have. The oil line 42 is provided with an oil on-off valve SV2 for controlling the supply or discharge of oil. A check valve 44 is connected in parallel with the oil on-off valve SV2. In this check valve 44, the flow toward one chamber 41 of the drive cylinder 33 is in the forward direction. Further, a flow control valve 55 with a check valve is connected to the oil line 42. The flow control valve 55 with a check valve includes a check valve 56 in which the flow toward one chamber 41 of the drive cylinder 33 is in the forward direction, and a throttle section 56.

The one chamber 4 of the drive cylinder 33
A high-pressure line 50 connected to a condenser (not shown), that is, a high-pressure region H is connected to the oil line 42 between
The check valve 51 is connected to the high-pressure line 50 so that the flow toward the one chamber 41 of the drive cylinder 33 is in the forward direction. This high-pressure line 50 is used when the load is forcibly down when stopped.

The other chamber 4 of the drive cylinder 33
7, a discharge line 48 for discharging gas is connected, and a gas on-off valve SV1 is connected to the discharge line 48.

A part of the oil line 42, the discharge line 48 and the high-pressure line 50 is connected to the manifold 6 shown in FIG.
0, the piping structure is extremely simple and compact, and no piping vibration is generated.

The screw compressor having the above-described structure is shown in FIG.
As shown in (B), the two on-off valves SV1 and SV2 are controlled to open and close to perform operations such as load-up, load-down, and load holding. In FIG. 1B, （indicates open, and × indicates closed.

First, during the load-up operation, the oil on-off valve SV2 is opened, while the gas on-off valve SV1 is closed. Then, the slide valve 32 is moved to the position shown in FIG.
Is pressed by the pressure difference of the refrigerant in the direction of arrow X (the side to be loaded up), and the drive cylinder 33
The other chamber 47 has a high pressure from between the piston rod 49 without the seal member and the bush portion 65 (see FIG. 2) in a state where the gas on-off valve SV1 is closed and cut off from the low pressure region L. Since the refrigerant has entered, the piston 35 of the drive cylinder 33 is also pressed to the left, and the oil in the one chamber 41 of the drive cylinder 33 is turned off by the oil line 42 and the oil on-off valve as shown by the arrow U1. The oil is discharged to the oil reservoir through the throttle portion 57 of the SV2 and the flow regulating valve 55 with a check valve. Thus, the piston 35 moves to the left,
The load is increased by moving the slide valve 32 in the arrow X direction. At this time, the check valve 51 of the high-pressure line 50 for forcibly loading down in the event of an abnormality or the like is closed.

At the time of the load-up, since the discharge speed of the oil discharged from one chamber 41 of the drive cylinder 33 is adjusted by the throttle portion 57 of the flow control valve 55 with a check valve, the transfer speed of the load-up is reduced. It can be adjusted with high precision over a wide range.

On the other hand, during the load-down operation, the gas on-off valve SV1 is opened and the oil on-off valve SV2 is closed. Then, as shown by the arrow D1, the check valve 1 of the flow control valve 55 with a check valve is removed from the oil pool.
4. High-pressure oil is supplied to one chamber 41 of the drive cylinder 33 through the oil line 12 and the check valve 44, while gas is supplied from the other chamber 47 of the drive cylinder 33 to the high pressure oil.
As shown by the arrow D2, the discharge line 48 and the on-off valve S
The air is discharged to the low-pressure area L via V1, the piston 35 moves to the right, and the slide valve 32 moves to the right (load-down side).

As described above, when the load-down operation is performed, the oil is supplied to the one chamber 41 of the drive cylinder 33 through the check valve 57 of the flow control valve 55 with the check valve. Oil can be supplied quickly and the load can be quickly reduced.

For example, when the load is forcibly reduced at the time of stoppage, the high-pressure refrigerant from the high-pressure line 50 is supplied to one chamber of the drive cylinder 33 through the check valve 51 as shown by an arrow D3 in FIG. 41 to quickly load down.

As shown in FIGS. 1A and 2, a notch 43 is formed in the piston rod 49 of the drive cylinder 33.
The notch 43 is overlapped with the bush 65 during the load-down operation, so that the drive cylinder 3
The inside of the other chamber 47 of 3 communicates with the outside high-pressure atmosphere, that is, the high-pressure area H through the notch 43. Therefore,
The movement of the drive cylinder 33 to the load-down side of the piston 35 is prevented, and the minimum partial load operation is guaranteed.

At the time of startup, as in the case of the load-down operation, the gas on-off valve SV1 is opened, the oil on-off valve SV2 is closed, and the unload operation is performed.

When the load is held, both the gas on-off valve SV1 and the oil on-off valve SV2 are closed, and the drive cylinder 3
The third piston 33 is stopped, and the slide valve 32 is stopped.

At the time of stoppage, the on-off valve SV1 for gas is opened and the on-off valve SV2 for oil is closed as in the case of startup.

The screw compressor is provided with an oil line 42
As shown by the arrow D1 and the arrow U1, a line dedicated to oil discharge is not provided for both supply and discharge of oil to one chamber 41 of the drive cylinder 33. Has the advantage of being simple and reducing the number of piping parts and of being inexpensive.

In addition, this screw compressor requires an on-off valve SV2 for oil and an on-off valve SV1 for gas.
Therefore, it is easy to control and extremely inexpensive.

In the above embodiment, since the check valve 44 is connected in parallel with the oil on-off valve SV2, oil from the tip of the oil line 42 is supplied to the one chamber 41 of the drive cylinder 33.
And the piping structure is simplified.

In the above embodiment, the oil line 4
2 and the discharge line 48 to one manifold 60
However, all or part of the high-pressure line 50 may be configured as one manifold together with the oil line and the discharge line. Further, a plurality of manifolds may be used. Further, in the above embodiment, no seal is provided between the piston rod 49 and the bush 65, but a seal such as a mechanical seal and a labyrinth seal may be provided.

[0051]

As is apparent from the above description, in the screw compressor according to the first aspect of the present invention, the oil line is used for both supply and discharge of oil to one chamber of the drive cylinder. There is an advantage that the piping structure is simplified, the number of piping components is reduced, and the risk of piping vibration is reduced because no line dedicated to discharge of water is provided.

The screw compressor according to the first aspect of the present invention uses two on-off valves, an on-off valve for oil and an on-off valve for gas, and does not use an on-off valve dedicated to oil discharge. Can be manufactured easily and inexpensively.

In the screw compressor according to the second aspect of the present invention, since the check valve is connected in parallel with the oil on-off valve, the oil from the tip of the oil line is driven without opening the oil on-off valve. And the control can be simplified.

The screw compressor according to the third aspect of the present invention is provided with a flow control valve with a check valve in which the flow toward the drive cylinder is an uncontrolled flow, so that the oil is quickly supplied to one chamber of the drive cylinder. Supply and load down quickly,
In addition, by adjusting the discharge speed of the oil discharged from the one chamber, the transfer speed of the load-up can be adjusted with high accuracy.

In the screw compressor according to the fourth aspect of the present invention, the high-pressure fluid is forcibly supplied from the high-pressure line to the one chamber of the drive cylinder through the check valve, so that the load can be quickly and reliably reduced.

In the screw compressor according to the fifth aspect of the present invention, at least two of the oil line, the discharge line and the high pressure line are constituted by one manifold, so that the piping structure is extremely simple and compact.

According to a sixth aspect of the present invention, a notch for setting a minimum partial load operation is provided in a piston rod of a drive cylinder, and the inside of the other chamber of the drive cylinder is driven through the notch through the notch. Since it is made possible to communicate with the high-pressure area outside, the minimum partial load operation can be easily guaranteed.

[Brief description of the drawings]

FIG. 1A is a circuit diagram of a screw compressor according to an embodiment of the present invention, and FIG. 1B is a diagram showing an operation state of an on-off valve of the screw compressor.

FIG. 2 is a sectional view of a part of the screw compressor.

FIG. 3 is a front view of the screw compressor.

FIG. 4A is a circuit diagram of a conventional screw compressor, and FIG. 4B is a diagram showing an operation state of an opening / closing valve of the screw compressor.

FIG. 5 is a front view of the conventional screw compressor.

[Explanation of symbols]

 31 screw rotor 32 slide valve 33 drive cylinder 35 piston 41,47 chamber 42 oil line 43 notch 44,51,57 check valve 48 discharge line 50 high pressure line SV1, SV2 on-off valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nozomu Goto 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yokogawa Works F-term (reference) 3H029 AA03 AA15 AA21 AB03 BB52 CC13 CC52 CC82

Claims (6)

[Claims] 1. A screw rotor (31), a slide valve (32) for controlling a capacity, and a drive cylinder (33) for driving the slide valve (32), wherein the slide valve (32) is loaded up. And a line (42) for supplying or discharging oil to one chamber (41) of the drive cylinder (33), and a line for oil ( 42), an oil on-off valve (SV
2) a check valve (44, 51) in which the flow toward one chamber (41) of the drive cylinder (33) is in the forward direction; and a check valve (47) of the other chamber (47) of the drive cylinder (33). A discharge line (48) for discharging gas, and a gas on-off valve (S) provided in the discharge line (48).
V1). 2. The screw compressor according to claim 1, wherein the check valve (44) is an oil on-off valve (SV).
A screw compressor connected in parallel to 2). 3. The flow control valve with a check valve according to claim 1, wherein a flow toward the drive cylinder (33) is uncontrolled in the oil line (42). A screw compressor provided with (55). 4. The screw compressor according to claim 1, wherein the oil on-off valve (SV2) is provided.
A high pressure line (5) connected to a high pressure side is connected to an oil line (42) between
0), and the high-pressure line (50) is provided with the check valve (51) in which the flow toward the one chamber (41) of the drive cylinder (33) is in the forward direction. Screw compressor. 5. The screw compressor according to claim 1, wherein said oil line (42) comprises:
A screw compressor, wherein at least two of the discharge line (48) and the high-pressure line (50) are constituted by one manifold (60). 6. The screw compressor according to claim 1, wherein the driving cylinder is a screw compressor.
A piston rod (49) provided with a notch (43) for setting a minimum partial load operation.