JPH0252775B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical field to which the invention pertains] The present invention relates to air conditioning control of so-called clean rooms where special operations such as VLSI manufacturing, assembly of precision machines, or biotechnology experiments involving unknown microorganisms are carried out. Regarding the method.

[Prior art and its problems]

In order to prevent the intrusion of dust from the outside world and maintain an ultra-clean environment, it is necessary to control the indoor pressure to positive pressure, and to prevent the leakage of bacteria and harmful substances to the outside world, it is necessary to control the indoor pressure to negative pressure. There is a need.

In response to these demands, a control method has been proposed that saves power for air supply and exhaust air conditioning fans by maintaining a constant air volume and room pressure indoors, and by adopting variable air volume operation for the fans. A conventional example of such a system will be explained to clarify the purpose of the present invention.

FIG. 3 is a block diagram showing a conventional example, in which the clean rooms 1, 1' each have a circulation duct 3, which has circulation fans 2, 2' to maintain the desired pressure inside the room.
3', and an ultra-high performance filter (HEPA filter) 4, is installed at the outlet of each duct 3, 3'.
4' is provided.

An air supply duct 6 provided with dampers 5, 5' is connected to the circulation fans 2, 2', and an air supply fan 7 is provided on the inflow side thereof. The dampers 5, 5' are controlled to open or close via controllers 9, 9' in accordance with the detection results of the disposed differential pressure gauges 8, 8'.

Further, a plurality of draft chambers 10, 10' are placed in the clean room 1, 1', and an exhaust fan 12 is provided in an exhaust duct 11 connected to the draft chambers 10, 10'. .

13 in the figure is a microcomputer for control,
The computer 13 includes a draft chamber 10,
The number of exhaust fans in use is detected by receiving an output from 10', and the rotational speed of the exhaust fan 12 is controlled based on this detection result. If a fluctuation occurs in the clean rooms 1, 1', the differential pressure gauges 8, 8' detect this and the controllers 9, 9' control the opening and closing of the dampers 5, 5'. By the way, if the desired pressure is not obtained even if the dampers 5, 5' are fully opened, the dampers 5, 5' send a fully open signal to the computer 13 via a limit switch (not shown) provided therein. The computer 13 receives this full open signal and controls the air intake fan 7 to increase its rotational speed.

By performing the two-step control of opening/closing the dampers 5 and 5' and controlling the rotation speed of the air supply fan 7 in this way, fine-grained control can be carried out, and the rotation speed of the air supply fan 7 can be controlled inadvertently. This makes it possible to realize power-saving operation without increasing the (For the above constant air volume constant room pressure control system, please refer to the magazine "Instrument")
) By the way, in the case where the clean rooms 1 and 1' are configured such that 1 is a high-pressure room and 1' is a low-pressure room, and they are connected to each other via a door 14, the door 14
When opened, air flows from room 1 to 1',
A so-called through pass occurs, and the constant air volume and constant room pressure control set for each room are significantly deviated from the target values. Further, even if the door 14 is closed, it takes a long time to restore the door to its original state.

[Purpose of the invention]

The purpose of the present invention is to eliminate the disadvantages of the conventional example,
Air conditioning for mobile work rooms that minimizes fluctuations caused by the formation of through paths between rooms, and enables quick recovery after the loss of through paths to prevent deterioration in control performance. The objective is to provide a control method.

[Key points of the invention]

However, according to the present invention, the purpose of the lever is to provide a clean room equipped with circulation ducts each having a circulation fan to maintain the indoor pressure at a desired pressure. An air supply fan is installed on the inflow side of the air duct, a draft chamber is installed in each clean room, and an exhaust duct with an exhaust fan is connected to these draft chambers, so that each clean room has a high pressure chamber and a low pressure chamber. In this case, the computer detects the number of draft chambers in use and controls the rotation speed of the exhaust fan, and detects room pressure fluctuations to control the opening and closing of the damper and the rotation speed of the supply fan. In the constant air volume constant room pressure control method that performs air control,
The damper can be opened and closed by a computer, and an opening/closing detector is provided on the door that connects the clean room divided into the high pressure room and the low pressure room, and when a door opening signal is received from the detector, the computer When the door is opened, the system determines whether the differential pressure between the clean room and its surroundings is within the allowable value, and if it is below the allowable value, increases the rotational speed of the air supply fan; If it is within the allowable value, this can be achieved by improving the followability of the damper in the high pressure chamber and decreasing the followability of the damper in the low pressure chamber.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart. In FIG. 1, the same components as in FIG. 3 showing the conventional example are given the same reference numerals.

In other words, clean room 1 of high pressure room and low pressure room,
The draft chambers 10, 10' in the draft chamber 1' send drive signals to the microcomputer 13, and the computer 13 receives this signal and controls the draft chamber 1.
The number of exhaust fans 12 used is detected and the number of rotations of the exhaust fan 12 is controlled accordingly. In the present invention, the pressure detection signals from the differential pressure gauges 8, 8' arranged in the rooms 1, 1' are introduced into the computer 13, and the damper 5, which is provided on the inflow side to the circulation fans 2, 2',
An opening/closing control signal from a computer 13 is introduced into damper 5', and the computer 13 controls opening/closing of dampers 5, 5'. This eliminates the need for the controllers 9, 9' (see Figure 3) that were conventionally required, and the opening/closing status of the dampers 5, 5' is determined by the opening/closing control signal (digital value) generated by the computer 13 itself. Since it can be detected by calculating the opening degree, limit switches and wiring provided on the dampers 5, 5' can also be omitted.

On the other hand, the point that a rotation control signal is given to the air supply fan 7 and the rotation speed is controlled by the computer 13 is the same as in the conventional case, and the computer 13 simultaneously detects the air volume of the air supply fan 7 by issuing this rotation control signal. It will be possible.

In this way, the opening and closing of the dampers 5, 5' and the air supply fan 7 are controlled in two steps. An opening/closing detector 15 using a limit switch is provided at the opening/closing detector 1.
The output signal of No. 5 is introduced into the computer 13.

As shown in FIG. 2, when the door 14 is opened, a door open signal is input to the computer 13 (step 1). Then, the computer 13 stops executing the control program that has been running so far, treats both the clean rooms 1 and 1' as one, and determines whether the differential pressure between the room and the surroundings is within the allowable value or less. to judge. If it is less than the allowable value, the rotational speed of the air supply fan 7 is increased to ensure the necessary differential pressure with respect to the surroundings (step).

Also, if it is within the allowable value, the followability of the damper 5 on the clean room 1 side, which is a high pressure room, is improved, and the followability of the damper 5' on the clean room 1' side, which is a low pressure room, is decreased (Step 2). . Note that improving followability means increasing the proportionality constant of the damper, that is, increasing the operating sensitivity. When the door 14 opens, a through path is formed, and the damper 5 opens due to the pressure drop in the clean room 1, increasing the amount of air to the room 1 and moving from the room 1 to the room 1', that is, from the high pressure room to the low pressure room. This will ensure airflow to. On the other hand, in the clean room 1', which is a low-pressure room, the damper 5' tries to close, but the pressure increases when the damper 5' is close to being fully closed, so there is no point in closing this damper 5'. There isn't. Rather, consideration was given to reducing the followability as described above so as to improve the recovery speed after the door 14 is closed and the through path disappears.

By the way, when the door 14 is closed, the computer 1 determines whether the door 14 has been open until now based on the time when the door close signal is sent from the open/close detector 15.
Step 3 is to judge (Step E). And door 14
If the dampers 5 and 5' are immediately closed, the followability of the dampers 5 and 5' is improved in order to further speed up recovery after the through path is lost (step 3). Furthermore, if the door 14 has been closed for a long time, the opening degree of the dampers 5 and 5' is controlled to perform normal constant air volume and constant room pressure control (step).

〔Effect of the invention〕

As described above, in the special work room air conditioning control method of the present invention, the computer detects the number of draft chambers in use and controls the rotation speed of the exhaust fan.
In a constant air volume constant room pressure control system that detects room pressure fluctuations and performs two-step air supply control: opening and closing of dampers and controlling the rotation speed of air supply fans, the clean rooms are connected by doors, and the opening and closing of the doors creates a through path. Even if this occurs, the fluctuation caused by this can be kept to a minimum, and recovery after the door is closed and the through path is lost can be done in a short time.
As a result, deterioration in control performance can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the air conditioning control method for a special work room according to the present invention, FIG. 2 is a flowchart showing the embodiment, and FIG. 3 is a block diagram showing a conventional method. 1,1'...Clean room, 2,2'...Circulation fan, 3,3'...Circulation duct, 4,4'...Ultra high performance filter, 5,5'...Damper, 6...Supply Air duct, 7... Air supply fan, 8, 8'... Differential pressure gauge, 9, 9'... Controller, 10, 10'... Draft chamber, 11... Exhaust duct, 12... Exhaust fan , 13...microcomputer, 14...
...Door, 15...Opening/closing detector.

Claims (1)

[Claims] 1 A clean room each equipped with a circulation duct with a circulation fan to maintain the desired pressure inside the room.
An air supply duct provided with a damper is connected to the circulation fan, an air supply fan is provided on the inflow side of the air supply duct, a draft chamber is installed in each clean room, and exhaust is supplied to the draft chamber. When exhaust ducts with fans are connected and each clean room is divided into a high pressure room and a low pressure room, the number of draft chambers used is detected, the computer controls the rotation speed of the exhaust fans, and room pressure fluctuations are detected. In the constant air volume constant room pressure control method, which performs two-step air supply control of opening and closing a damper and controlling the rotation speed of an air supply fan, the damper is capable of opening and closing control by a computer, and the high pressure chamber and the low pressure chamber are An open/close detector is installed on the door that connects two separate clean rooms, and when a door open signal is received from the detector, the computer detects the difference between the two clean rooms and their surroundings when the door opens. It is determined whether the pressure is within the permissible value, and if it is below the permissible value, the rotational speed of the air supply fan is increased, while if it is within the permissible value, the followability of the damper in the high pressure chamber is improved, and the low pressure chamber is A special work room air conditioning control method characterized by reducing the followability of a damper.