JPH11107983A - Surging preventing method and device for turbo compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the surging phenomenon by outputting a signal for closing a blow-off valve with a delay from the open signal of an inlet guide valve in shifting from unload to on-load operation, and outputting a signal for opening the blow-off valve earlier than the close signal of the inlet guide valve in the reverse transfer. SOLUTION: In the switching from unload to on-load, an inlet guide valve 1 is switched from close to open, and a first three-way solenoid valve 9 is opened by this signal to carry a pilot air to the operation part cylinder of a blow-off valve 11. At this time, the flow velocity of the air is reduced in a buffer tank, and the blow-off valve 11 is slowly closed because a delay is caused in the timing from open to close. In the reverse switching, the first three-way solenoid valve 9 and a second three-way solenoid valve 10 are closed, and the inlet guide valve 1 is switched from open to close by this signal. Thus, the surging of a turbo compressor can be prevented, and the compressor body can be protected to stabilize the air supply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method and an apparatus for preventing surging of a turbo compressor.

[0002]

2. Description of the Related Art A conventional operation of stopping the operation of a turbo compressor has been performed as shown in FIG. That is, a compressed air line is connected via a check valve 8 from a compressed air outlet of a turbo compressor having an inlet guide valve 1 to an intake air inlet, and an atmosphere discharge pipe 16 is connected to an inlet side of the check valve 8, A blow-off valve 11 is connected in the middle of the atmosphere discharge pipe 16, and an operating portion of the blow-off valve 11 and the check valve 8 are connected.
A pilot air circuit 14 is connected to the outlet side of
The flow control valve 12 and the first three-way solenoid valve 9 were connected in the pilot air circuit in order from the blow-off valve 11.

[0003] Then, switching from unloading to on-loading of the turbo compressor (b in FIG. 3, the blow-off valve is opened to closed).
Is performed by setting the air after the check valve as pilot air and closing the blow-off valve 11 from open to closed. Switching from on-load to unloading (d in FIG. 3, the blow-off valve is closed to open) is performed by releasing the air before the check valve 8 from the blow-off valve 11 to the atmosphere. FIG. 3C shows a state in which the blow-off valve is closed. Further, in FIG. 3, the inlet guide valve 1 is fully closed at a, fully opened at b, fully opened at the intersection of b and c, gradually closed at c, and closed (squeezed) at a stroke from the intersection of c and d at a stroke. Is fully closed.

[0004]

However, the speed from opening to closing of the blow-off valve 11 at the time of switching from unloading to on-load affects the performance curve of FIG. 3, and if the closing speed becomes too fast, the curve B Becomes large, enters the surge region in the figure, and surging occurs. In the prior art,
Adjustment of the closing speed of the blow-off valve 11 is performed by the flow control valve 12 in FIG. 2, and it is difficult to adjust the low speed, and surging frequently occurs. If surging occurs, there will be vibration accompanied by abnormal noise, which will damage the compressor body. Therefore, the compressor is stopped as a protection. The prior art has such a drawback. An object of the present invention is to solve the above-mentioned problems and to provide a method and an apparatus for protecting a compressor main body by preventing occurrence of surging of a turbo compressor and stabilizing air supply.

[0005]

Means for Solving the Problems To solve the above problems, the configuration of the present invention is as follows. That is, in the method of the first configuration, a compressed air line is connected via a check valve from a compressed air outlet of a turbo compressor having an inlet guide valve to an intake air inlet, and an atmospheric discharge pipe is provided at an inlet side of the check valve. Connected, a blow-off valve is connected in the middle of the air release pipe, a pilot air pipe is connected between the operating section of the blow-off valve and the outlet side of the check valve, and in the middle of the pilot air pipe. When the flow control valve and the first three-way solenoid valve are sequentially connected from the blow-off valve, and when shifting from unloading to on-load operation, the inlet guide valve is opened from closed to open, the blow-off valve is A signal to be closed is delayed from an open signal of the inlet guide valve,
When moving from on-load to unload operation, when the inlet guide valve is opened to close, a signal for opening the blow-off valve is given earlier than a signal for closing the inlet guide valve.

[0006] In the device of the second configuration, a compressed air line is connected via a check valve from a compressed air outlet of a turbo compressor having an inlet guide valve to an intake air inlet, and an atmospheric discharge pipe is provided on the inlet side of the check valve. Is connected, a blow-off valve is connected in the middle of the air discharge pipe, and a pilot air pipe is connected between the operating section of the blow-off valve and the outlet side of the check valve. A flow control valve and a first three-way solenoid valve are sequentially connected from the blow-off valve, and a second three-way solenoid valve and a buffer tank are provided in order between the blow-off valve and the control valve. .

[0007]

Embodiments of the present invention will be described below based on one embodiment shown in the drawings. In FIG. 1, 1
A receiver tank 13 of a compressed air line is connected via a check valve 8 from a compressed air outlet of a turbo compressor having a single-stage, two-stage, and three-stage compressors 2, 3, and 4. An inlet guide valve 1 is provided at an inlet of the single-stage compressor 2, and intercoolers 5 and 6 are provided between the compressors, and an aftercooler 7 is provided at an outlet side of a check valve 8. An air discharge pipe 16 is connected to the inlet side of the check valve 8, and a blow-off valve 11 is connected in the middle of the air discharge pipe, and the operating section of the blow-off valve 11 and the outlet side of the check valve 8 are connected to each other. A pilot air pipe 14 is connected between the two, and a flow control valve 12 and a first three-way solenoid valve 9 are connected in the middle of the pilot air pipe in order from the blow-off valve 11.

Here, a second three-way solenoid valve 10 and a buffer tank 15 are sequentially provided between the blow-off valve 11 and the regulating valve 12.

The operation state will be described above. First,
Switching from unloading to on-load is performed as follows. First, the inlet guide valve 1 is changed from closed to open. With this signal, the first three-way solenoid valve 9 is opened (AB and C stop), and the pilot air is
Blow-off valve 1 via three-way solenoid valve 10 (AB through, C stop)
It flows to the first operation unit cylinder. At this time, the flow velocity of the air in the buffer tank decreases, and the blow-off valve 11 is delayed from the opening to closing timing, closes slowly, and prevents surging.

Next, switching from on-loading to unloading is performed as follows. First three-way solenoid valve 9 and second
The three-way solenoid valve 10 is closed (both the first three-way solenoid valve and the second three-way solenoid valve pass B and C, and A is stopped). This signal changes the inlet guide valve 1 from open to closed. Here the blow-off valve 1
The air in the operation unit cylinder is the second three-way solenoid valve 10
Is released to the atmosphere from the opening C, and the blow-off valve 11 is instantaneously changed from closed to open. On the other hand, the air in the buffer tank 15 is released to the atmosphere from the opening C of the first three-way solenoid valve 9.

In switching from on-load to unload, FIG.
As shown by the performance curve, when the opening speed of the blow-off valve 11 is low, the slope of the curve d is reversed to become the curve d ′, so that the surge enters the surge region and generates surging. In the present invention, as described above, since the speed is conversely increased,
Surging is prevented.

The experimental results were as follows. In the conventional system, the surging frequency was about 0.5 times a month in the third year after the compressor operation started, and about 1 in the fourth year.
In the fifth year, it was about twice a month in the fifth year, and more than 20 times a month in the sixth year. After the installation of the buffer tank according to the present invention and the second three-way solenoid valve (from the seventh year), it occurred only once in seven months.

The present invention is not limited to the embodiments and embodiments described above, but includes various modifications without departing from the spirit and scope of the appended claims.

[0014]

According to the configuration of the present invention, the surging phenomenon of the turbo compressor is remarkably reduced.

[Brief description of the drawings]

FIG. 1 is a pneumatic circuit diagram of one embodiment of the present invention.

FIG. 2 is a conventional air circuit diagram.

FIG. 3 is a performance curve of a turbo compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet guide valve 2 1 stage compressor 3 2 stage compressor 4 3 stage compressor 5 1st intercooler 6 2nd intercooler 7 Aftercooler 8 Check valve 9 1st three-way solenoid valve 10 2nd three-way solenoid valve 11 Blow-off valve 12 Flow control valve 13 Receiver tank 14 Pilot air piping 15 Buffer tank 16 Atmospheric release valve

Claims (2)

[Claims] 1. A compressed air line is connected from a compressed air outlet of a turbo compressor having an inlet guide valve to an intake air inlet via a check valve, and an air discharge pipe is connected to an inlet side of the check valve. A blow-off valve is connected in the middle of the atmosphere discharge pipe, a pilot air pipe is connected between the operation section of the blow-off valve and the outlet side of the check valve, and a flow control valve and a flow control valve are provided in the middle of the pilot air pipe. When the first three-way solenoid valve is connected in order from the blow-off valve, the signal for closing the blow-off valve when the inlet guide valve is closed to open when shifting from unloading to on-load operation. A signal that delays the opening signal of the inlet guide valve and shifts the inlet guide valve from open to closed when moving from on-load to unload operation. , Surging prevention method of a turbo compressor, characterized by providing earlier than closing signal of the inlet guide valve. 2. A compressed air line is connected via a check valve from a compressed air outlet of a turbo compressor having an inlet guide valve to an intake air inlet, and an atmospheric discharge pipe is connected to an inlet side of the check valve. A blow-off valve is connected in the middle of the atmosphere discharge pipe, a pilot air pipe is connected between the operation section of the blow-off valve and the outlet side of the check valve, and a flow control valve and a flow control valve are provided in the middle of the pilot air pipe. A turbo compressor, wherein a first three-way solenoid valve is connected in order from the blow-off valve, wherein a second three-way solenoid valve and a buffer tank are provided in order between the blow-off valve and the regulating valve. Surging prevention device.