JP2015040668A - Exhaust device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust device which includes an airflow meter durable for a long-time use in an atmosphere of a corrosive gas, in which the airflow meter can be inspected and replaced without disassembling piping, and which can maintain a proper opening wind speed with small energy consumption by controlling an exhaust air amount according to an opening degree of a housing.SOLUTION: An exhaust device includes: a processing chamber; a housing for covering the processing chamber; a door for opening/closing an opening of the housing; exhaust means for exhausting gas in the processing chamber to the outdoors via an exhaust duct; air amount detection means for detecting the exhaust air amount of the gas flowing in the exhaust duct. In the air amount detection means, an impeller for rotating by receiving the flow of the gas flowing in the exhaust duct is arranged in the exhaust duct, and rotation detection means for detecting the rotation of the impeller is arranged outside of the exhaust duct.

Description

  The present invention relates to an exhaust device such as a local exhaust device, a table hood, a simple hood, a safety cabinet, a biohazard cabinet, and a clean bench.

  Patent Document 1 discloses a technique related to a variable air volume control device in a draft chamber or the like. In the variable air volume control device of Patent Document 1, an orifice is provided in the exhaust duct pipe, the exhaust air volume in the exhaust duct pipe is calculated from the pressure difference between the front and rear orifices, and the calculated ventilation air volume substantially matches the target ventilation air volume. The damper opening in the exhaust duct pipe is adjusted.

JP 2012-247121 A

  However, in Patent Document 1, corrosive substances such as acid and alkali may be included in the air flowing in the duct pipe, and when corrosive substances adhere to the pressure inlet of the orifice, the pressure inlet is It will corrode. If the pressure inlet of the orifice corrodes, there is a problem that the air volume cannot be detected accurately and the exhaust air volume cannot be controlled appropriately. Further, an experiment or the like may be performed without the operator noticing that the orifice is not operating normally.

  As a countermeasure, the orifice can be made using a material excellent in acid resistance and alkali resistance, but the cost becomes high. In addition, a hot-wire anemometer or a thermistor anemometer can be used as an anemometer, instead of the pressure detection method disclosed in Patent Document 1. However, in a corrosive gas atmosphere, the wind speed detector is corroded. One problem cannot be solved.

  Furthermore, in order to ensure the soundness of the orifice, the orifice is regularly inspected, but in order to inspect the orifice attached to the exhaust duct, the pipe connected to the draft chamber is disassembled. There is also a problem that the inspection work requires a lot of time and cost. Further, even when the orifice is broken and replaced, it is necessary to disassemble the pipe connected to the draft chamber, which requires a lot of time and cost for the replacement work.

  Further, the variable air volume control device of Patent Document 1 only calculates the exhaust air volume in the exhaust duct pipe, and only adjusts the damper opening in the exhaust duct pipe so that the calculated ventilation air volume becomes the target ventilation air volume. It does not consider the degree of opening of the body opening. As a result, when the exhaust air volume is set under the condition that the opening area of the housing is the maximum, if the opening area becomes small, the wind speed of the opening becomes higher than necessary, and the energy required for the exhaust becomes larger than necessary. . Conversely, if the exhaust air volume is set with the minimum opening area of the housing, when the opening area increases, the flow velocity of the opening portion decreases, and the air flowing through the opening portion may flow backward.

  The present invention has been made paying attention to such problems, and equipped with an air flow meter that can withstand long-term use even in an atmosphere of corrosive gas, without disassembling the piping, An object of the present invention is to provide an exhaust device capable of checking and replacing an air flow meter. It is another object of the present invention to provide an exhaust device that can reduce the energy consumption and maintain an appropriate opening air speed by controlling the amount of exhaust air according to the degree of opening of the housing.

In order to solve the above-described problem, an exhaust device of the present invention includes:
A processing chamber, a casing covering the processing chamber, a door for opening and closing an opening on the front surface of the casing, an exhaust means for exhausting the gas in the processing chamber to the outside through an exhaust duct, and a gas flowing through the exhaust duct An air volume detecting means for detecting the exhaust air volume of the exhaust air flow detecting means, wherein the air volume detecting means arranges an impeller that rotates in response to the flow of gas flowing through the exhaust duct in the exhaust duct, and A rotation detecting means for detecting the rotation of the impeller is arranged outside the exhaust duct.
According to this feature, the impeller that rotates in response to the flow of gas flowing through the exhaust duct is disposed in the exhaust duct, and the rotation detecting means that detects the rotation of the impeller is disposed outside the exhaust duct, thereby rotating Since the detection means can be kept away from corrosive gas, failure due to corrosion can be prevented, and the detection means can be used for a long time in a corrosive atmosphere. Further, since the rotation detection means is disposed outside the exhaust duct, the rotation detection means can be inspected and replaced without disassembling the exhaust duct.

The exhaust device of the present invention is
The air volume detection means includes a rotating shaft that supports the impeller, a bearing that rotatably supports the rotating shaft, a bracket that supports the bearing, a rotation detection plate attached to the rotating shaft, and a bracket. And a sensor for detecting the rotation of the attached rotation detection plate, and the air volume detecting means is inserted from the outside of the exhaust duct and attached to the exhaust duct.
According to this feature, since the air volume detecting means is inserted from the outside of the exhaust duct, the air volume detecting means can be attached, disassembled and inspected without disassembling the exhaust duct.

The exhaust device of the present invention is
The exhaust device further includes an opening / closing position detecting means for detecting an opening / closing position of the door, and the wind speed flowing through the opening on the front surface of the housing from the detection result of the air volume detection means and the detection result of the opening / closing position detection means. And the exhaust means is controlled so that the calculated wind speed substantially coincides with the target wind speed.
According to this feature, the exhaust air volume is controlled so that the wind speed calculated from the detection result of the air volume detection means and the detection result of the opening / closing position detection means substantially matches the target wind speed. Even if the degree changes, it is possible to maintain the appropriate wind speed of the opening, so that the wind speed of the opening is increased more than necessary, and the exhaust device can be prevented from consuming a great deal of energy. Conversely, it is possible to prevent the air flowing through the opening from flowing backward due to a decrease in the wind speed of the opening.

It is a figure which shows the example applied to the fume hood as the exhaust apparatus of this invention. (A) is a cross-sectional view which shows the structure of an air volume detection means, (b) is a side view of (a). It is a cross-sectional view which shows attachment and removal of an air volume detection means to an exhaust duct.

  EMBODIMENT OF THE INVENTION The form for implementing the exhaust apparatus which concerns on this invention is demonstrated below based on an Example.

  As an exhaust apparatus according to the present invention, a fume hood used when performing a chemical experiment or the like will be described as an example with reference to FIGS. 1 to 3. Reference numeral 1 in FIG. 1 is a fume hood to which the present invention is applied, and shows a state in which a door 6 that opens and closes an opening on the front surface of the housing is partially opened. The housing 2 has a processing chamber 3, and an exhaust duct 4 for exhausting the air in the processing chamber 3 is provided at the top of the housing 2.

  An air volume detecting means 20 for detecting the air volume of the gas flowing through the exhaust duct 4 is attached to the exhaust duct 4. The exhaust duct 4 is connected to and communicated with an exhaust duct 9 extended to the outside as indicated by a virtual line, and an exhaust fan 10 as an exhaust means is operated in the exhaust duct 9 so that a housing as shown in FIG. A flow of the suction air 12 from the front opening toward the internal processing chamber 3 is created. The motor for driving the exhaust fan 10 is driven at a variable speed by an inverter power supply (not shown) provided in the control device 14, and the exhaust air volume can be controlled by controlling the rotational speed of the motor 11. Yes.

  A fixed glass plate 5 made of tempered glass or the like is fixed above the opening on the front surface of the housing 2. Further, a door 6 is provided at a position below the fixed glass plate 5, and the user can change the opening area of the housing 2 by grasping the gripping side 8 and raising and lowering the door 6.

  The position of the door 6 can be detected by the opening position sensor 13, and the output of the opening position sensor 13 is input to the control device 14 described later, and the opening area of the lifting door is calculated.

  FIG. 2 shows an air volume detecting means 20 for detecting the air volume of the exhaust gas flowing through the exhaust duct 4. The impeller 21 rotates in response to the flow of gas flowing through the exhaust duct, the rotary shaft 22 that supports the impeller, and the rotary shaft. Bearings 23, 24 that support the bearing 24, a bracket 25 that supports the bearing 24, and a rotation detection means 28. The rotation detection means 28 is attached to the rotation detection plate 26 and the bracket 25 attached to the rotary shaft 22. Rotation sensor 27. The impeller 21 is arranged inside the exhaust duct 4, and the rotation detection plate 26 and the rotation sensor 27 that constitute the rotation detection means 28 are arranged outside the exhaust duct 4.

  When the impeller 21 receives the flow of exhaust gas and rotates, the rotation detection means 28 also rotates the rotation detection plate 26 attached to the rotation shaft 22, and the rotation sensor 28 detects the movement of the hole 29 provided in the rotation detection plate 26. 27 detects. As will be described later, the output signal of the rotation sensor 27 is input to the control device 14, and the control device 14 calculates the amount of exhaust air flowing in the exhaust duct 4 based on the output signal of the rotation sensor 27.

  Since the gas flowing through the exhaust duct 4 may contain corrosive gas, the impeller 21 that is in contact with the corrosive gas is made of a synthetic resin, metal, fiber reinforced plastic, or the like that is resistant to the corrosive gas. On the other hand, the rotation detection plate 26 and the rotation sensor 27 constituting the rotation detection means 28 are arranged outside the exhaust duct 4 so as not to come into contact with corrosive gas. Means can be used.

  As described above, the impeller of the air volume detecting means 20 is made of a material having high corrosion resistance, and the rotation sensor 27 is arranged outside the exhaust duct 4 so as not to come into contact with corrosive gas. Can withstand long-term use even in an atmosphere of corrosive gas. Further, since the rotation detection means is disposed outside the exhaust duct, the rotation detection plate 26 and the rotation sensor 27 can be inspected and replaced with the air volume detection means attached to the exhaust duct. Further, since the rotation detection means is arranged outside the exhaust duct, the rotation of the rotation detection plate 26 can be confirmed by visual observation, and the air flow detection device is not operating like the conventional air flow detection device. It also has the effect of preventing the person from noticing.

  FIG. 3 is a view for explaining how the air volume detection means 20 is attached to the exhaust duct 4. As shown in FIG. 3, the air volume detecting means integrally includes an impeller 21, a rotating shaft 22, bearings 23 and 24, a bracket 25, a rotation detecting plate 26, and a rotation sensor 27. The air volume detecting means 20 is inserted into the mounting hole 32 provided in the position 4, the bearing 23 is engaged with the mounting hole 31, and the bracket 25 is fixed to the exhaust duct 4 with the bolt 33. Can be completed. Further, the air volume detection means 20 can be removed from the exhaust duct 4 by the reverse procedure.

  As described above, since the air volume detecting means 20 is inserted from the outside of the exhaust duct 4 and can be attached to the exhaust duct 4, the air volume detecting means 20 is attached to the exhaust duct 4 without disassembling the exhaust duct 4. be able to. Similarly, since only the air volume detection means 20 can be removed from the exhaust duct 4 without disassembling the exhaust duct 4, the inspection and replacement work of the air volume detection means 20 is facilitated.

  The air volume detection method of the air volume detection means 20 will be described. The air volume detection means 20 is installed in a test duct simulating the exhaust duct 4 and flows a specified air volume, and the rotation sensor 27 detects the movement of the hole 29 provided in the rotation detection plate 26 when the impeller 21 rotates. The output of the rotation sensor 27 is counted, the rotation speed of the impeller 21 is calculated, and related data between the detected rotation speed and the air volume is collected. The control device 14 stores data related to the rotational speed of the air volume detection means 20 and the air volume. As will be described later, the control apparatus 14 detects the rotational speed of the impeller 21 from the output of the rotation detection means 28. Thus, the amount of exhaust air flowing in the exhaust duct 4 can be detected.

  Next, the operation of the control device 14 will be described. As shown in FIG. 1, the control device 14 inputs a detection signal from the opening position sensor 13 and a detection signal from the rotation detection means 28 provided in the air volume detection means 20. The area of the opening is calculated from the detection signal, the amount of exhaust air flowing through the exhaust duct is detected from the detection signal of the rotation detecting means 28, and the wind speed of the air flowing through the opening is calculated by dividing the amount of exhaust air by the area of the opening.

  When the calculated wind speed of the opening is lower than the set target wind speed, the control device 14 controls the output of the inverter power supply provided in the control device 14 and the rotational speed of the motor that drives the exhaust fan 10. To increase the exhaust air volume, and conversely, if the calculated wind speed of the opening exceeds the set target wind speed, control is performed to decrease the exhaust air volume by decreasing the motor rotation speed. .

  Thus, since the control device 14 controls the wind speed of the opening to be a desired wind speed, even if the operator changes the degree of opening of the door 6, the air speed of the opening is maintained at an appropriate wind speed. Can do. As a result, the wind speed of the opening becomes faster than necessary, and the exhaust fan 10 consumes a lot of energy, or conversely, the wind speed of the opening decreases and the air flowing through the opening flows backward. Can be prevented.

  Thus, since the exhaust device of the present invention includes an air flow meter that is durable even when used in a corrosive atmosphere for a long period of time, the reliability and safety of the exhaust device can be improved. Further, since the air flow meter can be inspected and replaced without disassembling the exhaust duct, the maintenance can be completed in a short time, so that the running cost can be reduced. Moreover, since the amount of exhaust air can be controlled according to the degree of opening of the housing, energy consumption is low and an appropriate opening air speed can be maintained. Furthermore, since the rotation detection means is arranged outside the exhaust duct, the rotation of the rotation detection plate can be confirmed by visual observation, and the air flow detection device is not operating like the conventional air flow detection device. Can also prevent you from noticing.

  In the embodiments, the fume hood is described as an example of the exhaust device, but the present invention is not limited to this, and the present invention is also applicable to an exhaust device such as a local exhaust device, a table hood, a simple hood, a safety cabinet, a biohazard cabinet, and a clean bench. it can.

DESCRIPTION OF SYMBOLS 1 Fume hood 2 Case 3 Processing chamber 4 Exhaust duct 5 Fixed plate glass 6 Elevating door 7 Elevating glass plate 8 Grip side 9 Exhaust duct 10 Exhaust means (exhaust fan)
DESCRIPTION OF SYMBOLS 11 Motor 12 Intake air 13 Opening position sensor 14 Control device 15 Cosmetic panel 20 Air volume detection means 21 Impeller 22 Rotating shaft 23 Bearing 24 Bearing 26 Rotation detection plate 27 Rotation sensor 28 Rotation detection means 29 Hole 31 Mounting hole 32 Mounting hole 33 Bolt

Claims (4)

  A processing chamber, a casing covering the processing chamber, a door for opening and closing an opening on the front surface of the casing, an exhaust means for exhausting the gas in the processing chamber to the outside through an exhaust duct, and a gas flowing through the exhaust duct An air volume detecting means for detecting the exhaust air volume of the exhaust air flow detecting means, wherein the air volume detecting means arranges an impeller that rotates in response to the flow of gas flowing through the exhaust duct in the exhaust duct, and An exhaust system characterized in that a rotation detecting means for detecting the rotation of the impeller is arranged outside the exhaust duct.   The air volume detection means includes a rotating shaft that supports the impeller, a bearing that rotatably supports the rotating shaft, a bracket that supports the bearing, a rotation detection plate attached to the rotating shaft, and a bracket. The sensor for detecting the rotation of the attached rotation detection plate is integrally formed, and the air volume detection means is inserted from the outside of the exhaust duct and attached to the exhaust duct. Exhaust system.   The exhaust device further includes an opening / closing position detecting means for detecting an opening / closing position of the door, and the wind speed flowing through the opening on the front surface of the housing from the detection result of the air volume detection means and the detection result of the opening / closing position detection means. The exhaust device according to claim 1 or 2, wherein the exhaust means is controlled so that the calculated wind speed substantially coincides with a target wind speed.   The exhaust device according to any one of claims 1 to 3, wherein the exhaust device is a local exhaust device, a table hood, a simple hood, a safety cabinet, a biohazard cabinet, or a clean bench.

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