JPS62186148A - Room pressure control system - Google Patents

Abstract

PURPOSE:To make it possible to put a room into a negative pressure in a manner almost the same as the case of a normal operation, to prevent the inside of the room from being put into an extraordinary negative pressure and also to prevent a precise and airtight housing and a duct system from being damaged by stopping an air feed fan when power supply is stopped, and operating an exhaust fan at a speed which is lower than that at a normal operation time by a power source for emergency use. CONSTITUTION:An air feed fan 9 is stopped when power supply is stopped, and power supply to a changeover damper 13 is stopped to close the same. At the same time, an exhaust fan 15 is operated at a low speed to reduce the capacity of an emergency power source 20. At the time of stoppage in power supply,the changeover damper 13 is closed and exhaustion of air from an auxiliary exhaust duct 14 is stopped. An exhaustion route from the air feed fan 9 to the exhaust fan 15 via an air feed port 7, a laboratory 1a, a safe cabinet 2a, and an opening and closing valve 6, is set. The laboratory 1a is put into a negative pressure, and the safe cabinet 2a is put into a more negative pressure. Thus, the negative pressure is increased according to the degree of danger thereby to prevent bacteria arrested by a filters 5 from re-scattering into the laboratory 1a and further dispersing to outside the laboratory 1a to maintain a desired cleanliness degree.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a biohazard countermeasure facility that prevents bacteria from leaking outside even during a power outage in a facility where bacteria are cultivated indoors maintained at negative pressure. Regarding power outage measures.

(Prior Art) Conventionally, in facilities where harmful bacteria are cultivated indoors, it is necessary to make the pressure in the room negative from atmospheric pressure in order to prevent the bacteria from leaking outside. The operation for this purpose was to operate the air supply fan after operating the exhaust fan.
It is described in 9-27140. That is, a technique is known that allows negative pressure to be maintained by only operating an exhaust fan.

(Problems to be Solved by the Invention) However, if only the exhaust fan is operated to maintain negative pressure as in the prior art, an ultra-abnormal negative pressure of, for example, -50 mmAq will occur indoors, causing problems in precision airtight buildings and The duct system will be damaged.

(Means for Solving the Problems) Therefore, as a means for solving the above problems, the present invention provides an isolation area 2 in a closed chamber 1 for culturing bacteria isolated from the inside of the chamber 1. , the lower air supply of room l is connected to the air supply fan 9 by an air supply duct I+, the isolation area 2 is connected to the exhaust duct 12, and the exhaust port 8 of room l is connected to the air supply duct I+ by an auxiliary exhaust duct 14. Exhaust fan 15
During steady operation, air is supplied by the air supply fan 9, and the exhaust fan is connected to the air supply fan 9. 5 to evacuate the chamber to negative pressure, and isolate the isolation area 2.
This is a room pressure control system that makes the inside of the room a more negative pressure than the inside of the room, and in the event of a power outage, the air supply fan 9 is stopped and the exhaust fan 15 is operated by the emergency power source 20 at a lower speed than during normal operation. It is something.

(Function) By using the above-mentioned means, the present invention stops the supply air fan 9 during a power outage, and even if only the exhaust fan 15 is operated, the exhaust fan 15 is operated at low speed, so that ultra-abnormal negative pressure is not generated. ,
Precise airtight buildings and duct systems will not be damaged.

(Embodiment) A room pressure control system in a biohazard countermeasure facility as a preferred embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, la is a laboratory as a sealed room l, and 2a is a movable safety cabinet as an isolation area 2 installed in the laboratory la, and harmful bacteria are stored in the safety cabinet 2a. are being cultivated.

3 and 4 are the air inlet and air outlet of the safety cabinet, respectively.

5 is a high-performance particulate filter (hereinafter abbreviated as a filter) provided inside the air outlet 4 to prevent leakage of harmful bacteria, and 6 is a semi-fixed opening/closing valve for adjusting the wind M.

Therefore, an air supply lower with a filter 5 is provided on the ceiling of the laboratory 1a, and an exhaust port 8 with a filter 5 is provided on the wall near the floor. The device 10 is connected by an air supply duct ti, and air is supplied by an air supply fan 9.

On the other hand, the on-off valve 6 is connected to an exhaust duct 12 that airtightly penetrates the laboratory room 1a and leads out of the laboratory la, and also connects the exhaust port 8 of the laboratory room 1a to an auxiliary exhaust duct 14. A switching damper 13 is interposed in the exhaust duct 12.
and the auxiliary exhaust duct 14 are joined outside the laboratory la, and an exhaust fan 15 is disposed on the downstream side thereof, and the exhaust fan 15 exhausts the laboratory room la. Here, the switching damper 13 is of a normally closed type, which is open when energized and closed when power is interrupted, and whose opening degree can be adjusted when energized is opened.

16 is a power source, and the air supply fan 9, exhaust fan 15, and switching damper 13 are each connected to the power source 16.

Reference numeral 17 denotes a differential pressure transmitter that detects and transmits the differential pressure between room pressure and atmospheric pressure, and operates a differential pressure regulator 18 in response to a command from the differential pressure transmitter 17, which is interposed in the auxiliary exhaust duct 14. Switching damper 1
Perform the opening adjustment in step 3.

In addition, 19 is a voltage detection device connected to the power supply 16, and when the voltage drop (25% or more) of the power supply 16 is connected for more than 2 seconds, the voltage detection device 19 outputs a signal to the emergency power supply 20 to create an emergency. This commands the operation of the power generator. The emergency power source 20 is connected only to the exhaust fan 15.

Steady operation in the laboratory 1a with the above configuration is performed as follows. The air supply fan 9 and the exhaust fan 15 are respectively operated, the switching damper 13 is energized, and air supply and exhaust are performed along the paths shown by the solid line arrows. The supply air volume is fixed, the opening degree of a switching damper 13 is adjusted to control the exhaust air volume, and a constant air volume and ventilation frequency are always maintained regardless of the operating conditions of indoor appliances.

Here, the cause of fluctuations in the supply air m is the change over time due to the clogging of the filter 5, and in response to this, the constant air flow device 10 absorbs the clogging of the filter 5 and other pressure fluctuations, and constantly It is designed to ensure a stable and constant air volume.

On the other hand, since the exhaust volume also changes over time due to clogging of the air outlet 4 of the safety cabinet 2a and the filter 5 of the exhaust port 8, it is necessary to provide a mechanism to ensure a constant air volume for this purpose. In the case of 10
However, since there are multiple safety cabinets 2a in the laboratory la, and it is difficult to maintain the room pressure against such irregular operations, in this case, the differential pressure transmitter 17 described above is used. This may be used to command the differential pressure regulator 18 to adjust the opening degree of the switching damper 13.

As described above, the supply air amount was fixed at a constant amount, and the laboratory room Ia
The exhaust volume is adjusted by the switching damper 13 according to the operating status of the equipment inside the room, and the room pressure is constantly maintained at a predetermined negative pressure (approximately -5 mmA Q
), the inside of the safety cabinet 2a is maintained at a higher negative pressure (approximately -12 mmAq) than the inside of the laboratory la, and the negative pressure is increased in order of increasing danger. This prevents substances from spreading outside the room.

Next, measures against a power outage, which is a feature of the present invention, will be explained.

In order to operate the air supply fan 9, exhaust fan 15, and switching damper 13 during a power outage, the capacity of the emergency power supply 20 will be too large, so the air supply fan 9 will be stopped and the switching damper 13 will be activated.
At the same time, the exhaust fan 15 also operates at low speed and with low airflow 1 to reduce the capacity of the emergency power source 20. In order to operate the exhaust fan 15 at a low speed, the electric motor of the exhaust fan 15 is, for example, 4 [! It uses a convertible electric motor with 8 poles, and operates at 4 poles at high speed during normal operation, and at 8 poles at low speed using the emergency power supply 20 during a power outage.

The following controls are automatically performed at the same time as a power outage (see Figures 2 and 3). Power outage (SPI) during normal operation (SPI)
When the voltage drop (25% or more) continues for 2 seconds or more due to F3), the voltage detection device 19 detects this and issues a start command to the emergency power supply (S P3).
4) At the same time, order to take measures for devices other than the exhaust fan 15, which are devices required for residual operation in an emergency, that is, to stop the operation of the air supply fan 9 and to stop energizing the switching damper 13 and close it.5P5) Number conversion (4 poles → S poles)
, commands low speed operation (SF3). Once the power outage is restored (
SF3), which returns to the original normal operation (SPI).

Note that emergency operation is limited to 2 to 3 hours.

Due to the control described above, the room pressure, which was maintained at -5 mmAq during normal operation, increases due to a power outage, but the air supply fan 9
Due to the inertia of the exhaust fan 15, the room pressure does not rise rapidly and the negative pressure is maintained.

Approximately 10 seconds after the power outage, the emergency power supply starts operating, and the emergency power supply 20 causes the exhaust fan 15 to operate at low speed, causing the room pressure to rapidly recover and stabilize at approximately -IOmmAQ (Figure 3). .

Here, the reason why the exhaust fan 15 is operated at low speed and low air flow during a power outage is that the air supply fan 9 is stopped, so the exhaust fan I
When 5 is operated at normal speed, the distance inside laboratory Ia is 150 m.
This would create an extremely abnormal negative pressure of about mAq, which would damage the precision airtight building and duct system, but this can be prevented by low-speed operation.

That is, when the fan is operated at a low speed that is 1/2 of the normal speed, the exhaust air volume becomes summer/2, and the total pressure of the fan decreases to (1/2)2. If the total pressure during steady state is 50mmAq, the total pressure during power outage Ps = 50x (1/2)" = 12.5m
mAq, and the negative pressure corresponding to the pressure increase of this exhaust fan becomes the room pressure in the laboratory 1a, and the pressure inside the laboratory Ia is -10 to -15 mm.
It is held at Aq.

Also, since the shaft horsepower of the fan is (1/2)'', for example, if the output of the exhaust fan 15 is 0.75KW, then 0.
75×(1/2)3=o, lH, and the emergency power source 20 can be made extremely compact and economical.

As described above, in the event of a power outage, the switching damper 13 is closed to stop the exhaust from the auxiliary exhaust duct 14, and the air supply fan 9, air supply lower, laboratory 1a, safety cabinet 2a, on-off valve, etc. 6. The exhaust duct 12 and the exhaust fan 15 are used as the exhaust route, and the inside of the laboratory la is kept under negative pressure (-10
~-15mmAq), the inside of the safety cabinet 2a was further increased in negative pressure, and the negative pressure was increased in descending order of the degree of danger, and the bacteria collected by the filter 5 were re-dispersed into the laboratory la. Furthermore, it prevents this from spreading outside the laboratory and maintains cleanliness.

In addition, as described in the embodiment section, by making the switching damper 13 a normally closed type that closes in the event of a power outage, the exhaust route can be automatically connected to high-risk areas such as Room 1 and Isolation Area 2 without the need for complicated operations. In this order, the negative pressure increases and the safety level of the device increases.

(Effects of the Invention) As described above, the room pressure control system of the present invention has the following remarkable effects.

(1) If the exhaust fan I5 is not operated at low speed during a power outage, the air supply fan 9 will be stopped, resulting in abnormal negative pressure (-
50 mmAq), which would damage the precision airtight building and duct system, but the exhaust fan 15 can be operated at low speed, the negative pressure can be maintained almost the same as during steady operation, and the above defects can be prevented. It is.

(2) In addition, during a power outage, only the exhaust fan 15 is operated and the exhaust fan 15 is operated at low speed, so it can be operated with lower power than during normal operation, and the capacity of the emergency power supply 20 can be extremely reduced. (compared to the conventional system)
15), and the installation space is small, making it extremely economical.

[Brief explanation of drawings]

Fig. 1 is a piping and wiring diagram of a room pressure control system in a biohazard countermeasure facility as an embodiment of the present invention, Fig. 2 is a flowchart showing the control of the system in Fig. 1 during a power outage, and Fig. 3 is the same system. It is a graph showing the relationship between time and room pressure. l...Room la...Laboratory 2...Isolation area 2a...Safety cabinet 7...Air supply port 8...Exhaust port 9 ... Air supply fan 11 ... Air supply duct 12 ... Exhaust duct 13 ... Switching damper 14 ... Auxiliary exhaust duct 15 ... Exhaust fan 20 ...Emergency power supply

Claims (1)

[Claims] 1. An isolation area (2) for cultivating bacteria isolated from the inside of the chamber (1) is provided in the closed chamber (1), and an air supply port (2) of the chamber (1) is provided.
7) is connected to the air supply fan (9) through the air supply duct (11), and the isolation area (2) is connected to the air supply fan (9) through the exhaust duct (12).
), and the exhaust port (8) of the chamber (1) is connected to the auxiliary exhaust duct (14) by a single exhaust fan (15).
During steady operation, air is supplied by the air supply fan (9) and exhausted by the exhaust fan (15), creating a negative pressure in the room (1) and moving the inside of the isolation area (2) into the room (1). A room pressure control system that creates an even greater negative pressure, which stops the air supply fan (9) and also controls the exhaust fan (15) in the event of a power outage.
A room pressure control system that operates at a lower speed than during steady operation using an emergency power source (20). 2. A switching damper (13) to the auxiliary exhaust duct (14)
2. The room pressure control system according to claim 1, wherein the switching damper (13) is of a normally closed type, which opens when electricity is applied and closes when there is a power outage.