JPH0668407B2 - Absolute pressure control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an absolute pressure control device, and in particular, enables an absolute pressure in an absolute pressure target chamber to be precisely controlled to a set pressure even if the atmospheric pressure fluctuates. The present invention relates to an absolute pressure control device.

[Conventional technology]

Recently, many precision positioning devices have been adopted in fields such as the semiconductor industry. Generally, in this type of device, an optical length measuring device is provided,
When the pressure of the atmosphere, that is, the atmospheric pressure changes, the refractive index of the air between the measuring chambers changes, and as a result, a measuring error occurs, making precise positioning difficult. Therefore, when using the optical length measuring device, the absolute pressure of the environment in which it is placed must be controlled to be constant.

Conventionally, a device having a configuration as shown in FIG. 2 has been used as a device for controlling the absolute pressure. In FIG. 2, an outside air fan 3 is connected to the outside air intake 1 via an outside conditioner 2, and an air conditioner 5 is connected to the outside air fan 3 via a constant air volume valve 4. . On the other hand, the outlet of the air conditioner 5 is connected to an absolute pressure target chamber 8 via a ventilation pipe 6 and an air filter 7. The absolute pressure target chamber 8 is provided with a circulation air port 9 and an exhaust air port 10, a constant air volume valve 11 is connected to the circulation air port 9, and a ventilation pipe 12 is connected to the constant air volume valve 11. It is connected to the inlet side of the air conditioner 5 via the. On the other hand, the exhaust air outlet 10 has an exhaust fan
A pressure control valve 13 and a pressure control valve 14 are connected to each other, and the pressure control valve 14 is connected to an exhaust port 15. Here, the pressure control valve 14 has an absolute pressure gauge 16 installed in the room.
It is connected via a signal line 18 via 17.

In the apparatus shown in FIG. 2 configured as described above, the air sent to the outside air intake 1, the outside air conditioner 2, the outside air fan 3, and the air conditioner 5 is controlled to a constant air volume by the constant air volume valve 4. To be done. Further, the amount of air returning from the absolute pressure target chamber 8 to the air conditioner 5 through the circulating air port 9 is controlled to a constant air amount by the constant air amount valve 11 on the way. Therefore, the amount of air sent into the absolute pressure target chamber 8 is also constant.

On the other hand, the absolute pressure in the absolute pressure target chamber 8 is measured by the absolute pressure gauge 16
Is detected by the controller 17, the valve opening of the pressure control valve 14 is adjusted by the controller 17, and the amount of exhaust from the absolute pressure target chamber 8 is controlled from the exhaust air port 10 through the exhaust fan 13 to obtain the set value. Is controlled to be.

[Problems to be solved by the invention]

However, in the conventional device described above, the control performance of the constant air volume valve is low, and particularly when trying to set a constant air volume with a low air volume, a setting error of about ± 20 mmH ₂ O occurs with respect to the set value, and There was a problem of being out of control. There is also a problem that it takes a very long time to reach the set pressure when the inlet / outlet of the absolute pressure target chamber 8 is opened / closed or the exhaust device in the chamber 8 is operated.

The object of the present invention is made in view of the above-mentioned problems, and it is possible to precisely control the absolute pressure in the absolute pressure target chamber, and moreover, to make it possible to quickly control to the set absolute pressure. An object of the present invention is to provide an absolute pressure control device capable of avoiding the influence on the room pressure due to the pressure change of the outside air.

[Means for solving problems]

In order to achieve the above-mentioned object, an absolute pressure control device according to the present invention is an air conditioner that harmonizes air blown into an absolute pressure target room and returns it to the room, and an intake that is air-conditioned to this air conditioner. In an absolute pressure control device including an outside air fan that sends outside air and an exhaust system that exhausts the air in the room to the outside so as to keep the air in the room at a preset absolute pressure, a confluence point of circulating air from the absolute pressure target room An absolute pressure gauge for detecting the pressure of the intake air sent to the air conditioner on the upstream side, a pressure control valve installed on the upstream side of the absolute pressure gauge, and a signal from the absolute pressure gauge, A regulator for adjusting the valve opening of the pressure adjusting valve to a set pressure that is set to be substantially equal to the absolute pressure of the circulating air that merges on the downstream side.

[Action]

According to the above configuration, the intake outside air is controlled to a set pressure that is set to be substantially equal to the absolute pressure of the circulating air in a state independent of the circulating air whose pressure is adjusted on the upstream side from the confluence point with the indoor circulating air. Therefore, the pressure of the intake outside air is controlled to be substantially constant regardless of the atmospheric pressure fluctuation of the outside air, so that the absolute pressure in the absolute pressure target chamber is maintained at the set value with high control accuracy. In addition, since both the air supply side and the exhaust side are held and adjusted to a preset absolute pressure, the set pressure can be quickly set against internal pressure such as entering and exiting the absolute pressure target chamber or exhaust from this chamber. Can be recovered to.

〔Example〕

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an absolute pressure control device according to the present invention, and the same parts as those in FIG. 2 are designated by the same reference numerals.

The present embodiment is different from the conventional example in that the constant air volume valve 4 is provided in the conventional example, whereas in the present example, the pressure adjusting valve 19 is provided on the outlet side of the outside air fan 3.
And a controller for adjusting the valve opening of the pressure adjusting valve 19.
20 and an absolute pressure gauge 21 for inputting a control signal of the regulator 20. The absolute pressure gauge 21 is located on the downstream side of the pressure control valve 19 and the ventilation pipe 12 is provided in the air conditioner 5.
It is installed on the upstream side of the point (merging point) connected to the upstream side of. Further, the pressure control valve 19 and the exhaust side pressure control valve 14 have the same characteristics.

On the other hand, in the middle of the ventilation pipe 12 connected to the air conditioner 5 from the circulating air port 9 provided in the absolute pressure target chamber 8,
An air volume control valve 22 and an air volume detector 23 are provided, and the air volume control valve 22 and the air volume detection 23 are connected to a controller 24 via a control line 25, respectively.

Next, the operation of the absolute pressure control device configured as described above will be described. The intake outside air that is sent from the outside air intake 1 through the outside air conditioner 2 and the outside air fan 3 to the air conditioner 5 is feedback controlled, that is, the detection value of the absolute pressure gauge 21 on the way is sent to the controller 20 and set. By adjusting the valve opening of the pressure adjusting valve 19 by the deviation from the pressure value (this set pressure value is set to be approximately equal to the absolute pressure of the circulating air that joins), the absolute pressure Is controlled to a constant pressure value.

Therefore, when the pressure in the absolute pressure target chamber 8 drops considerably below the absolute pressure, the deviation between the pressure of the circulating air and the set pressure of the pressure control valve 19 becomes large, and the amount of outside air taken into the absolute pressure target chamber 8 increases. Will increase. In this way, when the amount of outside air taken into the absolute pressure target chamber 8 increases, the pressure in the absolute pressure target chamber 8 rises to the absolute pressure, and the pressure drop in the absolute pressure target chamber 8 recovers in a short time.

On the other hand, when the pressure in the absolute pressure target chamber 8 is slightly higher than the absolute pressure, the pressure difference between the lowered pressure and the set pressure of the pressure control valve 19 becomes small, so that the outside air intake into the absolute pressure target chamber 8 is reduced. The input amount is small. Therefore, the pressure in the absolute pressure target chamber 8 decreases and the pressure slightly higher than the absolute pressure in the absolute pressure target chamber 8 recovers to the absolute pressure in a short time.

In this case, the pressure adjusting valve 14 will be described later together with the pressure adjusting valve 19.
The valve opening of is adjusted.

On the other hand, a part of the intake outside air sent to the absolute pressure target chamber 8 is sent to the inlet side of the air conditioner 5 from the circulation air port 9 through the air flow control valve 22 and the air flow detector 23. On this occasion,
In response to the signal from the air volume detector 23, the controller 24 adjusts the valve opening degree of the air volume adjustment valve 22, whereby the circulating air volume is set to be equal to the set air volume. In addition, part of the air is exhausted from the exhaust air port 10 to the exhaust fan 13 and the pressure control valve.
After passing through 14, the gas is exhausted from the exhaust port 15, but at this time, the signal of the absolute pressure gauge 16 in the absolute pressure target chamber 8 is received to adjust the valve opening degree of the pressure adjusting valve 14, whereby the The absolute pressure in the absolute pressure target chamber 8 is controlled so as to be kept constant.

In the device of the present embodiment configured as described above, the pressure of the outside air taken into the absolute pressure target chamber 8 is controlled to be substantially constant irrespective of atmospheric pressure fluctuations. It is necessary to control the indoor pressure adjustment that is performed by adjusting the valve opening degree of with a very small fluctuation range.
The absolute pressure in the absolute pressure target chamber 8 can be maintained at the set value with high control accuracy.

Further, pressure control valves 19 and 14 having the same characteristics are provided on the air supply side and the exhaust side, whereby the door is opened / closed when entering / exiting the absolute pressure target chamber 8 and arranged in the chamber 8. There is an effect that the set pressure can be restored in a short time even with respect to internal disturbance such as exhaust from the exhaust device to the outside.

〔The invention's effect〕

As described above, according to the absolute pressure control device of the present invention, an air conditioner that harmonizes the air blown into the absolute pressure target room and returns it to the room, and the intake outside air that is air conditioned by the air conditioner. In an absolute pressure control device having an external air fan for sending air and an exhaust system for exhausting the air in the room to the outside so as to keep the air at a preset absolute pressure, the confluence point of the circulating air from the absolute pressure target room An absolute pressure gauge for detecting the pressure of the intake air sent to the air conditioner on the upstream side, a pressure control valve installed on the upstream side of the absolute pressure gauge, and a signal from the absolute pressure gauge, Since it has a configuration that adjusts the valve opening of the pressure adjusting valve so that the set pressure is set to be substantially equal to the absolute pressure of the circulating air that joins, it is particularly mixed with the indoor circulating air. Before taking in Since it can be introduced by adjusting to the absolute pressure of the conditioned air, the fluctuation of the external atmospheric pressure is absorbed and the disturbance pressure is prevented from mixing with the circulation system. Can be controlled precisely,
Moreover, there is an excellent effect that the set pressure can be promptly recovered even with respect to the internal pressure of the absolute pressure target chamber and internal disturbance such as exhaust from the chamber.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an absolute pressure control device according to the present invention, and FIG. 2 is a schematic configuration diagram showing an example of a conventional device. 3 ... Outside air fan, 5 ... Air conditioner, 8 ... Absolute pressure target chamber, 10 ... Exhaust air port, 14, 19 ... Pressure adjusting valve,
16, 21 …… Absolute pressure gauge, 17,20 …… Adjuster.

Claims (1)

[Claims] 1. An air conditioner for harmonizing air blown into an absolute pressure target chamber and returning it to the absolute pressure target chamber again, an outside air fan for sending intake outside air in air condition to the air conditioner, and In an absolute pressure control device provided with an exhaust system that exhausts air to the outside so as to hold the air at a preset absolute pressure, on the upstream side of the confluent point of the circulating air from the absolute pressure target chamber, and of the outside air fan. An absolute pressure gauge provided on the downstream side for detecting the pressure of the intake air sent to the air conditioner, a pressure control valve installed between the absolute pressure gauge and the outside air fan, and a signal of the absolute pressure gauge. And an adjuster for adjusting the valve opening of the pressure adjusting valve to a set pressure that is set to be substantially equal to the absolute pressure of the circulating air that merges on the downstream side. Control device.