JPS5822690B2 - Pressure monitoring and operating device for vacuum equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure monitoring and operating device that monitors and controls the pressure of a vacuum device, and in particular detects, shuts off, and exhausts abnormal pressure conditions suitable for preventing damage to vacuum devices due to pressure rise. The present invention relates to a pressure monitoring and operating device for a vacuum device for operating a vacuum device.

BACKGROUND ART Conventionally, in a vacuum device, when a part of the device breaks and outside air fluid leaks, the following means have been used to detect, shut off, and exhaust the air.

In Figure 1, a protection unit 1゜2.3 consisting of a plurality of vacuum equipment and piping (not shown), a process wiring W6L62 that connects this protection unit, and a shield installed in this process piping are shown. 12 and 13, normal process fluids are being processed.

Protection units 1, 2 and 3 each have a normal exhaust valve 21.22
, 23, and emergency exhaust valves 31, 32, 33 are connected to the valves 21, 22, 23, 31, 32, 33.
, is closed under normal operating conditions.

In this state, for example, when a part of the protection unit 2 breaks and outside air fluid leaks in, the pressure change will be as shown in FIG. 2.

In other words, it is operating normally until time to, and until time t
.

Suppose that a part of protection unit 2 breaks at .

At this time, the pressure in each protection unit gradually increases, but the rate of increase varies depending on the location of the rupture and the size of the rupture. Since the pressure at the pressure gauge 72 does not necessarily rise first, the pressure at the pressure gauges 71 and 7
2, 73, when the level becomes high (that is, at time tt). Close and isolate all protection units 1, 2, 3-.

In this state, there is no outside air fluid leaking into the normal protection units 1 and 3, so the indications on the pressure gauges 71 and 73 gradually change toward the equilibrium state of the independent protection units 1 and 3. It only does this.

On the other hand, since the outside air leaks into the broken protection unit 2, the pressure increases even more rapidly and the level increases.

At this time t2, it is learned that the protective unit 2 has been ruptured, and by opening the emergency exhaust valve 32 shown in FIG. By evacuating the units 1 and 3 using the normal exhaust device 20, the process fluid in the ruptured protection unit is prevented from flowing out to the outside air, and the vacuum equipment in the normal protection unit is also prevented from being damaged due to the pressure increase. There is.

However, the drawbacks of this method are (1) the pressure limit (upper limit) and the durability time of the vacuum equipment within the protection unit are relatively low; therefore, the set value of the level height shown in FIG. 2 cannot be increased;

(2) Therefore, depending on the location and size of the rupture, the pressure of the normal protection unit reaches a high level first, so that, for example, the normal protection unit 1 is removed from the emergency exhaust system 30.
．． Both the normal protection unit 3 and the broken protection unit 2 are evacuated by the normal exhaust device 20.

Prevention in this case. Outside air will flow back from protection unit 2 to protection unit 3, damaging normal equipment in protection unit 3.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to quickly shut off and isolate a vacuum device in which an abnormality has occurred, and to smoothly discharge gas from the vacuum device in which an abnormality has occurred, thereby preventing damage to the vacuum device. There is a particular thing.

The present invention detects abnormal pressure points using the output signals of the pressure gauge that detects the pressure for each protection unit and the differential pressure gauge that detects the pressure difference between both ends of the shield well, and closes the corresponding shield well, thereby identifying the abnormal protection unit. This makes it possible to isolate the equipment and perform two types of exhaust operations, emergency and normal, to prevent accidents from spreading that could lead to damage to normally protected unit equipment.

An embodiment of the present invention will be explained with reference to FIG.

Protection units 1, 2, and 3, which are composed of a plurality of vacuum machines and piping (not shown in FIG. 3), are connected to process piping 61, 62.

A shield well 12, 13 is installed in this process piping, and when an abnormality occurs [i"closed", each protection unit is isolated.

Each protection unit is connected to an emergency exhaust header 5 via emergency exhaust pipes 51, 52, 53 and emergency exhaust valves 31, 32, 33.
4 to the emergency exhaust system 30.

In addition, each protection unit has normal exhaust piping 41, 42. .

43 and a normal exhaust header 44 to the normal exhaust device 20.

The emergency exhaust valves 31, 32, and 33 are "open" only for the abnormal protection unit and closed for the normal protection unit.

Normal exhaust valves 21゜22.23 are open only for normal protection units.''
Therefore, the abnormality protection unit is "highly closed".

During normal operation, all of the wells except for the shield wells 12 and 13 are in a "closed" state.

In order to reliably detect pressure abnormalities, in addition to conventional pressure gauges, differential pressure gauges 81 and 82 were installed to detect the pressure difference between both ends of the shield wells 12 and 13.

Next, the operation of the pressure monitoring and operating device of the present invention will be explained with reference to the block diagram shown in FIG.

■ Detection method for abnormal pressure points Detection of pressure abnormalities is performed using differential pressure gauges 81 and 82.

The differential pressure gauge 81 detects the pressure difference between two points P and -P at both ends of the pressure gauge 12, and when the value reaches a specified value, an output signal appears.

When a part of the protection unit 1 or 2 breaks, the pressure of the broken protection unit increases due to leakage of outside air.

The pressure difference between PIF2 at both ends of the shiarai increases.

p3- where the other differential pressure gauge 82 attempts to measure the pressure difference
It is determined whether the protection unit 1 or 2 has caused a breakage accident, depending on whether or not a differential pressure appears between the protection units 1 and 2.

In other words, if the differential pressure gauge 81 indicates "differential pressure tomorrow" and the differential pressure gauge 82 detects the differential pressure, the AND of A3 is established and it is determined that a rupture accident has occurred in the protection unit 2. 1
3. Close and isolate each protection unit.

Also, if the differential pressure gauge 82 is not detecting differential pressure, the N2
The output of the OT circuit is present, the AND of A1 is established, it is determined that a breakage accident has occurred in the protection unit 1, the breaker 12 is closed, and the protection unit 1 is isolated.

If the differential pressure gauge 82 detects that there is a differential pressure and the differential pressure gauge 81 does not detect that there is a differential pressure, the output of the NOT circuit of N1 is present, the AND of A2 is established, and it is determined that a rupture accident has occurred in the protection unit 3. Arai 13 is closed and protection unit 3 is isolated.

■ Distinguishing between emergency exhaust and normal exhaust If a breakage accident occurs in protection unit 2, Arai 12, 13. Since the valve was closed, the pressure rose further due to the leakage of outside air.

Detecting the high pressure of the pressure gauge 72 of protection unit 2, and assuming that the pressure gauges 71 and 73 of other protection units 1 and 3 do not detect the high pressure, AND of A5 is established and emergency evacuation is performed. valve 32
The normal exhaust valves 21 and 23 of the normal protection units 1 and 3 are opened and the exhaust operation is performed.

That is, in order to prevent backflow from the abnormal protection unit to the normal protection unit via the exhaust system line, the output conditions of the pressure gauges are compared and the exhaust valve is opened.

Therefore, it is possible to reliably prevent damage to normally protected unit equipment due to backflow in the conventional method.

If the protection unit 1 ruptures, the pressure gauge 71 detects a high pressure, and the pressure gauges 72 and 73 do not detect a high pressure.If the protection unit 3 ruptures, the pressure gauge 73 detects a high pressure. When the pressure gauge 7L72 detects no high pressure, the corresponding emergency exhaust valve and normal exhaust valve are opened and the exhaust operation is performed.

As described above, according to the embodiment of the present invention, even in the event of an accident in which a part of the protection unit breaks, the accident protection unit is reliably isolated, and the abnormal protection unit is operated in an emergency manner, and the normal protection unit is normally exhausted, thereby reducing the area of the accident. This makes it possible to minimize the damage and prevent it from spreading to the normal protective status.

According to the present invention, since the output signal of the difference meter is used to operate the shutoff valve, it is possible to isolate the abnormal vacuum equipment in a short time, and to switch from the abnormal vacuum equipment to the normal vacuum equipment. The inflow of outside air can be minimized.

Since the vacuum equipment in which the abnormality has occurred is immediately switched to the emergency exhaust system, it is possible to prevent the gas exhausted from the normal vacuum equipment from mixing with the gas exhausted from the abnormal vacuum equipment.

Vacuum equipment in which an abnormality has occurred can be isolated in a short time, and gas exhaust from the vacuum equipment can be switched from a normal exhaust system to an emergency exhaust system, so damage to the vacuum equipment can be prevented.

[Brief explanation of drawings]

Fig. 1 is a system diagram of the conventional example, Fig. 2 is a characteristic diagram showing pressure changes in the conventional example, Fig. 3 is a system diagram showing an embodiment of the present invention, and Fig. 4 is a pressure monitoring system of the present invention. FIG. 3 is an operational block diagram of the operating device. 1.2,3...Protection unit, 12,13...Shutoff valve, 20...Normal exhaust system, 21,22,23...Normal exhaust valve, 30...Emergency exhaust system, 31, 32, 33
...Emergency exhaust valve, 41, 42, 43... Normal exhaust piping, 44... Normal exhaust header, 51, 52, 53
...Emergency exhaust piping, 54...Emergency air header, 6
1゜62...process piping, 71. 72, 73...
・Pressure gauge, 8L81 differential pressure gauge.

Claims (1)

[Claims] 1. In a pressure monitoring and operating device for a vacuum device that has a plurality of vacuum devices, piping that connects the vacuum devices, and a strain relief well provided in this piping, a plurality of differential pressure gauges are installed to measure the differential pressure between both ends of each strain relief well. Attach each to the above piping,
Each vacuum device is provided with a pressure gauge, and when the differential pressure is detected by the differential pressure gauge, a first valve is installed to close the arai, which is attached to the piping in which the differential pressure gauge is installed. Gas from a vacuum device having a control means, in which the pressure signal output from the pressure gauge exceeds the set value and when the differential pressure signal output from the differential pressure gauge is input, the pressure signal exceeds the set value. A pressure monitoring and operating device for a vacuum device, comprising a second control means for switching exhaust from a normal exhaust system to an emergency exhaust system.