JPS60140036A - Concentrated exhaust system - Google Patents

Abstract

PURPOSE:To realize the stable and highly accurate control of an exhaust fan motor by a constitution wherein a blower is controlled by the result of comparison between the air flow rate flowing in an exhaust duct and the set initial reference value of air flow rate in the titled automatic exhaust fan motor control type system. CONSTITUTION:The initial reference value of inducing air flow rate is selected in accordance with the magnitude of an indicator draft capacity and set at an air flow rate setting circuit 15. In addition, an exhaust fan motor 21 is put into operation and the openings of manual/automatic dampers of scheduled draft chambers are adjusted to the magnitudes of the capacities of the respective chambers. After that, when the number of the draft chambers in operation changes during the operation of the system, a differential calculator 17 compares the detection signal of an air speed sensor 9 with the reference value of an air rate setting circuit 15 in order to increase or decrease the rotational frequency of the motor 21 through an inverter 19. Due to the constitution as mentioned above, the minimum exhaust air flow rate required can be supplied in response to the number of the draft chambers in operation, resulting in obtaining the stable and highly accurate control of the exhaust fan motor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention generally relates to a centralized exhaust system, and more particularly to a centralized exhaust system that automatically controls the drive of an exhaust fan motor provided in a main exhaust duct.

[Prior art 1] This type of centralized exhaust system generally includes a plurality of (for example, about 5 to 10) drums 71 to chambers, and manual or automatic dampers that are provided in the plurality of chambers and can be opened freely.
It has a main exhaust duct that communicates each chamber with the outside of the installation room and is equipped with one exhaust fan. A central exhaust system is typically installed in a chemical experiment room where hazardous materials such as harmful gases are tested. Therefore, in order to ensure the safety of experimenters during experimental work, it is necessary to constantly monitor the driving status of the exhaust fan motor and check the ventilation capacity of the system.

By the way, in order to drive such a centralized exhaust system having a plurality of drums 71 and 17 members, one exhaust fan motor provided in the main exhaust duct is driven as described above. Therefore, not only chambers in use but also unused chambers must be evacuated, which requires the exhaust fan motor to be operated at full capacity, resulting in extremely high air conditioning costs and is extremely uneconomical.

Therefore, in order to improve this drawback, the system detects the number of draft chambers in use or the number of unused pilaf L-chambers, and operates the system with an exhaust air volume commensurate with the number of draft chambers in use. is proposed. However, in the above proposal, the number of open/closed dampers is detected, so if, for example, the damper is half open instead of fully open, it is not clear which number of dampers should be included in the number of open/closed dampers. Therefore, for example, if all the dampers are half-open, the exhaust fan motor must be operated at full capacity.Furthermore, because the duct system is complex, one exhaust point is actually required [ It also has the disadvantage of falling below the level of air.

If we try to improve this drawback, we will have to increase the exhaust volume to some extent, which is another drawback:
1- I end up doing it. In any case, in the above proposal, the draft
It has been difficult to control a stable and highly accurate exhaust fan motor that can supply the minimum amount of exhaust air ω depending on the number of Chitonbas used.

[Purpose J Therefore, the present invention has been made in view of the points 11 and 2 of the prior art, and its purpose is to supply the minimum necessary IJI ff1ffl according to the number of trough channels used. An object of the present invention is to provide a centralized exhaust system capable of controlling an exhaust fan motor in a stable and highly accurate manner.

1. Outline of the present invention] The features of the present invention to achieve the above object include a plurality of troughs 1-chambers forming an experimental work space with a door that can be opened freely, and a blowing means to blow air into the plural work spaces. The main exhaust duct l~ which recirculates the air and then forcibly exhausts it outside the installation room.
and a monitor 4J+ air duct 1~ for monitoring the exhaust status to the main exhaust duct 1, in which the main 1/1 air duct 3- and the monitor I+ air duct Alternatively, at least one of the plurality of experimental work spaces is provided with means for detecting the inflowing dose, and an air volume standard is set for setting an initial reference value of the air volume generated by driving the air blowing means at the start of driving the system. A value setting means is provided to compare and calculate the detected value given from the air volume detection means and the M quasi value given from the Kawawaki M quasi-haku setting means, and control the driving of the air blowing means according to the result of the calculation. A means is installed (in the central exhaust system).

[Example code] The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a centralized exhaust system according to the present invention, and FIG. 2 is a block circuit diagram of a control device for the centralized exhaust system according to the present invention.

In FIG. 1, reference numeral 1 is an exhaust fan, and the exhaust fan 1 is rotationally driven by an exhaust motor 21 shown in FIG. The main exhaust duct]~3 is equipped with the exhaust fan 1 and communicates with each draft chamber 5 via an exhaust passage 4.

4- The pilaf 1 to the chamber 5 each have a manual/white moving damper 7, and the retraction i into each chamber is adjusted to a preset opening depending on the capacity of each chamber.
t is determined. The air volume detection means 9 may be any sensor that measures the volume of exhaust air 111ffl flowing into each chamber 5 from the installation room and exhausted from the 1L main exhaust duct 1 to the outside, or the exhaust air volume from the monitor exhaust duct. In the example, a wind speed sensor was used. The controller 11 is an exhaust fan motor 2 that drives the exhaust fan 1.
1 (shown in FIG. 2), the details of which will be explained in FIG.

In FIG. 2, the air volume setting circuit 15 is configured to adjust the air volume setting circuit 15 according to the capacity of the draft chamber 5 (hereinafter simply referred to as "indicator draft") in which the wind speed sensor 9 is installed. This is a circuit that can selectively set an initial reference value. The differential calculator 17 converts the intake air volume at the sensor installation location based on the wind speed sensor information given from the wind speed sensor 9, and compares it with the dose reference value output from the air volume setting circuit 15 to calculate the calculation result. Based on this, a predetermined level signal is output to control the drive of the exhaust fan motor 21. The inverter 19 receives the output signal given from the differential arithmetic unit 17.
After C/A C conversion, it is output to the exhaust fan motor 21. For example, a horizontal-phase induction motor is used as the exhaust fan motor 21.

The controller 11 shown in FIG. 1 includes an air volume setting circuit 15, a differential calculator 17, and an inverter 19.

The control operation of the above configuration will be explained mainly with reference to FIG. 2.

When using the centralized exhaust system according to this embodiment, the experimenter selects an initial reference value of the drawn-in air volume according to the capacity of the index draft with the manual/automatic damper 7 fully open, and sets this value to the air volume. After setting the initial reference value of the air volume in the air volume setting circuit 15, the experimenter turns on the exhaust fan motor 21 (not shown) while keeping the manual/automatic damper 7 of the index draft fully open. Close the switch. This causes the motor 21 to start driving and the operation of the central exhaust system to begin.

The index draft assumes that while the central exhaust system is in operation, the manual/automatic damper 7 is always in the full state as described above, regardless of how the draft is used. Next, the opening degree of the manual/automatic damper 7 of the draft chamber 5 to be used is adjusted in accordance with the capacity of each chamber. If, for example, 5 out of 10 draft chambers 5 are in use at the start of system operation, but the number increases to 7 in the middle, the amount of air drawn in between the opening/closing of each draft chamber 5 and the index draft Since there is a certain correlation between changes in , the amount of air drawn into the index driver 71 decreases. The differential calculator 17 constantly converts the detected signal given from the wind speed sensor 9 into an air volume, and then performs a comparison operation with reference value information given from the air volume setting circuit 15.

Therefore, when the differential calculator 17 recognizes that the air volume drawn by the index driver 71 has become smaller than the INl amount reference value based on the detection signal given from the wind speed sensor 9, the A drive command signal is output to increase the rotation speed.

When the differential calculator 17 recognizes that the intake air volume of the index draft has become equal to the quasi-value of the ffl amount M based on the detection signal given from the wind speed sensor 9, the differential calculator 17
Stop the signal output that was being given to 9.

On the contrary to the above, when the number of draft chambers 5 used at the start of operation of the system, for example, five, is reduced to three, the drawn-in air volume in the index draft increases. In this case, the differential arithmetic unit 17 performs control in the same manner as described above, but in a reverse manner, so a description thereof will be omitted.

The content described above is merely one embodiment according to the present invention, and for example, the wind speed sensor 9 may be attached to the main exhaust duct 1 or a monitoring exhaust duct. Also, no problem will arise if a pressure sensor is used in place of the wind speed sensor 9. In other words, as long as the amount of exhaust gas from a central exhaust system can be measured with high precision, it is not limited to a specific location or specific equipment.

As mentioned above, if a chamber is being used without being affected by the use/non-use of other draft chambers, the opening degree of the manual/automatic damper should be adjusted according to the capacity of the chamber. If adjusted, the amount of drawn air commensurate with the chicken room will always be supplied.

[Effect] As explained above, according to the present invention, the detected value given from the detection means is compared with the reference value given from the air volume reference value setting means, and the blowing means is driven according to the result of the calculation. Since it is decided to control the air blowing means, it is possible to control the air blowing means with a stable and high precision that can supply the minimum necessary exhaust air volume depending on the number of draft chambers used. Furthermore, it is possible to significantly reduce air conditioning maintenance costs. Furthermore, since the number of parts can be greatly reduced, it is possible to provide a low-cost centralized exhaust system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the central exhaust system according to the present invention, and FIG. 2 is a block circuit diagram of a control device for the central exhaust system according to the present invention. 1... Exhaust fan 17... Differential extractor 3...
Main exhaust duct] ~ 21...Exhaust fan motor 5...
・Trough l-chamber 7...Manual/automatic damper 9...Wind speed sensor 15...Air volume setting circuit Figure 1 Figure 2 11- Procedural amendment voluntarily) Commissioner of the Japan Patent Office May 1980 Kazuo Wakasugi 1. Indication of the case: Japanese Patent Application No. 58-245045 2. Name of the invention: Centralized exhaust system 3. Relationship with the case of the person seeking amendment: Patent applicant address (residence): Nihonbashi, Chuo-ku, Tokyo. Honmachi 2-9-5
Name: Yamato Scientific Co., Ltd. Representative: Tatsumi Morikawa 4, Agent: 11 Location: 1-2-3-5 Toranomon, Minato-ku, Tokyo 105
, date of notice of reasons for refusal Showa year month day (voluntary) 1
- 6. Specification subject to amendment 7, Contents of amendment (1) On page 9, lines 15 to 18 of the specification, it states, "For example, the wind speed sensor 9... will not cause any trouble." [For example, a branch path may be provided in the main exhaust duct 1 and a wind speed sensor 9 for detecting the intake wind speed may be attached to the branch path, or the sensor 9 may be attached to a monitoring exhaust duct. do not have. Further, instead of attaching the wind speed sensor 9 to the main exhaust duct 1 or the monitor exhaust duct as described above, a pressure sensor may be attached inside the main exhaust duct 1 without causing any problem. ” he corrected. 2-

Claims (1)

[Claims] A plurality of drums 71-chambers forming experimental work spaces with doors that can be opened freely; a main exhaust duct that forcibly exhausts the air outside the installation room after recirculating the air in the plurality of work spaces using a blowing means; In a centralized exhaust system having an exhaust duct and a monitor exhaust duct for monitoring the exhaust status of the exhaust duct, the amount of air flowing into at least one of the main exhaust duct, the monitor exhaust duct, or the plurality of experimental work spaces is controlled. and an air volume reference value setting means for setting an initial reference value of the air flow generated by the operation of the air blowing means when starting the operation of the system. A centralized exhaust system, comprising means for comparing and calculating a reference value given from the air volume reference value setting means and controlling the driving of the air blowing means in accordance with the result of the calculation.