JP2012087997A - Circular dust collecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circular dust collecting device which can effectively remove dust from an operating room generating a lot of dust and can reduce electricity consumed by an air conditioning unit.SOLUTION: The circular dust collecting device includes: a blower 13 for sucking air in the operating room 2; a dust filter 14 for filtering the air sucked through the blower 13 to remove dust contained in the sucked air; a returning channel 15 for returning at least one part of the air filtered through the dust filter 14 to the operating room 2; and a purifying filter 16 arranged in the returning channel 15, and for further filtering the air to be returned to the operating room 2.

Description

  The present invention relates to a circulation type dust collector that collects dust by a filter and returns purified air to the original working chamber.

  A resin composition for encapsulating a semiconductor for encapsulating a semiconductor chip, etc. is a sheet-like composition after stirring each component such as an epoxy resin, a curing agent, a curing accelerator, a release agent, a flame retardant, and a colorant with a mixer. Then, it is crushed with a hammer and formed into a tablet of a desired shape. At that time, a large amount of dust is generated, resulting in a decrease in reliability of the molded product due to contamination of the equipment and a deterioration of the working environment (see Patent Document 1). In an environment where such a large amount of dust is generated, it is generally performed to collect the dust scattered by the dust collector.

  In addition, when a semiconductor chip is sealed using a tablet molded into a predetermined shape, the tablet is supplied to a sealing molding apparatus by a vibration conveyor or the like, but dust is generated from the tablet itself or dust attached to the tablet. Or scatter. Therefore, it has also been proposed to attach a dust collecting device to the sealing molding device itself so that dust does not adhere to the vicinity of the molding die (see Patent Document 2).

  According to a conventional dust collector, dust is removed by a filter, and the purified exhaust gas is thrown away outdoors. However, when the air in the work room (for example, in a factory building) is exhausted outdoors by the dust collector, the work room becomes negative pressure, and new air flows from outside the work room (for example, outside). Usually, the working room is temperature-controlled and humidity-controlled at a temperature of 15 to 20 ° C. and a humidity of 30 to 50%. When new air having a temperature difference and / or a humidity difference flows from outside the work room, the air conditioning equipment must be operated to control the temperature and humidity, and the power consumed by the air conditioning equipment increases.

JP-A-10-128742 JP-A-9-219414

  The present invention has been made to solve the above-described problems of the conventional example, and enables reduction of electric power consumed by the air conditioning equipment while efficiently removing dust from a working room where a large amount of dust is generated. It aims at providing a circulation type dust collector.

  In order to achieve the above object, a circulating dust collector according to the present invention includes a blower for sucking air in a working chamber, and the air sucked by the blower is filtered and included in the sucked air. A dust removal filter for removing dust, a return duct for returning at least a portion of the air filtered by the dust removal filter to the work chamber, and a filter provided in the return duct for further filtering the air returned to the work chamber It is characterized by having a purification filter for the purpose.

  The said structure WHEREIN: It is preferable that the said purification | cleaning filter is comprised by the at least 2 type of filter from which a material differs.

  Furthermore, it is preferable that at least a part of the return duct is charged so as to electrostatically adsorb floating dust.

  The total area of openings for returning air from the return duct to the working chamber is preferably larger than the area of the suction side opening of the blower.

  According to the configuration of the present invention, since at least a part of the exhaust that has been thrown away outdoors is returned to the original working chamber, the pressure drop in the working chamber is reduced, and a new amount of air flowing from outside the working chamber Is reduced. Moreover, the temperature and humidity of the air returned to the work room are not much different from the temperature and humidity of the original work room. Therefore, when the air conditioning equipment is operated to adjust the temperature and humidity, the power consumed by the air conditioning equipment can be greatly reduced compared to the conventional one. Although it is filtered by a dust removal filter, the exhaust that is thrown away outdoors contains a small amount of dust, but the amount of exhaust that is thrown away outdoors also decreases, which further reduces pollution in the outdoor environment. it can. Furthermore, since the air returned to the working chamber is further filtered by the purification filter, dust hardly circulates in the working chamber.

The figure which shows the basic structure and installation state of the circulation type dust collector which concerns on one Embodiment of this invention. The figure which shows the modification of the circulation type dust collector which concerns on one Embodiment of this invention. The figure which shows the other modification of the circulation type dust collector which concerns on one Embodiment of this invention.

  A circulation type dust collector according to an embodiment of the present invention will be described. FIG. 1 shows a basic structure of the circulating dust collector 1 and a state where the circulating dust collector 1 is installed in a work chamber 2 where a large amount of dust is generated, for example, a semiconductor chip sealing operation. The work room 2 is inside a building 3 such as a factory, and a semiconductor chip sealing device 4 is installed therein. In addition, a temperature control / humidity control device 5 that controls the temperature and humidity in the work chamber 2 to a certain range is provided on the wall surface 3 a on the work chamber 2 side of the building 3. A plurality of hoods (intake ports) 11 are attached to the ceiling 3 b on the work room 2 side of the building 3 corresponding to the sealing device 4 and the like. Each hood 11 is connected to a blower 13 via a suction duct 12. For example, a dust removal filter 14 is provided at a joint portion between the suction duct 12 and the blower 13 (intake side of the blower 13). Further, a return duct 15 for returning a part or all of the air filtered by the dust removing filter 14 to the work chamber 2 is connected to the exhaust side of the blower 13. The return duct 15 is provided with a dust filter 14 for further filtering the air returned to the work chamber 2. Further, the return duct 15 is provided with a ventilator 17 for exhausting part or all of the air sucked by the blower 13 to the outside as necessary.

  In the configuration example shown in FIG. 1, the blower 13 and the dust removal filter 14 are attached to the ceiling 3 b of the work chamber 2, and the main part of the return duct 15 is provided vertically along the wall surface 3 a of the building 3. . An opening 15 a on the air return side of the return duct 15 is formed in the lower part of the wall surface 3 a of the building 3. In this configuration example, the air in the work chamber 2 is sucked from the ceiling portion 3 b, and the air purified by the dust collector 1 is returned from the vicinity of the floor surface 3 c of the work chamber 2 of the building 3. In addition, the position of the opening 15a on the air return side of the blower 13, the dust removal filter 14, the purification filter 16, and the return duct 15 is not particularly limited, and may be provided at other positions.

  The dust removal filter 14 and the purification filter 16 have a plurality of types such as a primary filter for removing coarse dust having a relatively large particle diameter and a secondary filter for removing fine particles for removing fine particles that cannot be removed by the primary filter. It consists of a combination of filters. Depending on the work performed in the work chamber 2 and the type of dust generated, the type and combination of filters used are appropriately changed. In the case of the semiconductor chip sealing operation, for example, a quasi-HEPA filter is used as the secondary filter, and for example, 95% or more of dust having a particle diameter of 0.3 μm can be removed. When a HEPA filter is used, dust can be removed with higher efficiency.

  When the blower 13 is driven, the air in the work chamber 2 is sucked into the suction duct 12 through the hood 11 and passes through the dust removal filter 14. At that time, most of the dust contained in the sucked air is filtered by the dust removing filter 14. Part or all of the air sucked by the blower 13 and filtered of the dust by the dust filter 14 passes through the return duct 15, further passes through the purification filter 16, and returns to the work chamber 2. That is, the circulation is circulated while being filtered by the circulation type dust collector 1 while being filtered by the circulation type dust collector 1. Since the air filtered by the dust removal filter 14 is filtered again by the purification filter 16, the air returned to the working chamber 2 contains almost no dust, and the dust hardly circulates in the working chamber.

  Although the air in the work chamber 2 is circulated while being filtered by the circulation type dust collector 1, the work chamber 2 and the circulation type dust collector 1 are not completely sealed, so the air sucked by the blower 13. Leaks to the outside or air flows into the work chamber 2 from the outside. In addition, the ventilator 17 may be periodically released, a part of the air sucked by the blower 13 is exhausted to the outside, and fresh air is taken in from an intake port (not shown) and replenished. . On the other hand, the inside of the work chamber 2 is temperature-controlled and humidity-controlled by a temperature control / humidity control device 5 to, for example, an air temperature of 15 to 20 ° C. and a humidity of 30 to 50%. However, according to this circulation type dust collector 1, a part or all of the air in the working chamber 2 which has been sucked by the blower 13 and was conventionally thrown away outdoors is returned to the original working chamber. Therefore, the pressure drop in the work chamber 2 is reduced, and the amount of new air flowing from the outside of the work chamber 2 is reduced. Further, the temperature and humidity of the air returned to the work chamber 2 are not so different from the original temperature and humidity of the work chamber. Therefore, when the temperature control / humidity control device 5 is operated to perform temperature control / humidity control, the power consumed by the temperature control / humidity control device 5 can be greatly reduced as compared with the conventional one.

  The hood 11, the suction duct 12, the return duct 15 and the like are generally manufactured by forming a metal plate into a cylindrical shape. Therefore, in order to prevent the temperature and humidity of the air returned from the circulating dust collector 1 to the work chamber 2 from changing much from the original temperature and humidity of the work chamber, the hood 11, the suction duct 12, and the return duct 15 are used. The portion that touches the outside air may be covered with the heat insulating material 18. Even when the outside air is lower than the room temperature of the work chamber 2, the portions of the hood 11, the suction duct 12, and the return duct 15 that are in contact with the outside air are covered with the heat insulating material 18, so that not only the temperature is lowered but also drying due to condensation is performed. And mold can be prevented.

  The air flow generated by the blower 13 passes through the return duct 15, further passes through the purification filter 16, and returns to the work chamber 2 from the opening 15 a. In general, the amount of air generated by the blower 13 is related (for example, proportional) to the amount of dust generated in the work chamber 2, but in this embodiment, the work chamber 2 where a large amount of dust is generated is assumed. Therefore, the air volume generated by the blower 13 is considerably large. Therefore, even if the pressure loss due to the purification filter 16 is taken into consideration, the flow velocity of the air returned (blowed out) from the opening 15a on the air return side of the return duct 15 to the work chamber 2 is considerably high. Since the opening 15a on the air return side of the return duct 15 is provided in the vicinity of the floor surface 3c of the work chamber 2, there is a possibility that dust that has left the floor 3c will be wound up. Therefore, the total area of the air return side opening 15a of the return duct 15 is made larger than the area of the suction side opening of the blower 13, thereby slowing the flow velocity of the air returned to the work chamber 2. Good. The flow rate of air returned to the work chamber 2 is preferably 3 m / s.

  FIG. 2 shows a modification of the circulating dust collector 1. In this modification, the hood 11 is provided on a surface 3 d that is the wall surface of the work chamber 2 of the building 3 and faces the opening 15 a on the air return side of the return duct 15. The hood 11 is provided in the vicinity of the ceiling 3 b of the work chamber 2, unlike the opening 15 a on the air return side of the return duct 15. In this case, the total area of the air return side opening 15a of the return duct 15 is made smaller than the area of the suction side opening of the blower 13, and the air blown out from the opening 15a is generated in the work chamber 2. You may make it blow off dust to the hood 11 side.

  FIG. 3 shows another modification of the circulating dust collector 1. In this modification, a part of the return duct 15 is charged by the power source 20 or the like, and the floating dust P (exaggeratedly drawn) that could not be removed by the dust filter 14 is electrostatically adsorbed on the inner wall of the return duct 15. Remove. In this way, fine particles finer than the eyes of the dust filter 14 can be removed. In addition, the charging process for electrostatically adsorbing the floating dust is not limited to the one in which the power source is directly connected to the feedback duct 15, and may be other charging processes such as charging by friction with air. . For example, a blowout of a resin sheet or the like may be provided inside the return duct 15. Furthermore, you may perform a charging process so that a floating dust may be electrostatically adsorbed to at least one part of the return duct of the circulation type dust collector 1 of the structure shown in FIG. If there is a possibility that the material used in the work chamber 2 may explode, it is preferable to remove the charge by grounding the return duct 15 without performing the charging process.

Assuming that the circulating dust collector 1 is applied to the applicant's semiconductor chip sealing factory, the energy saving effect was calculated. As a result, the energy saving was 370,000 kWh / year and the CO ₂ equivalent was 200 t / year. It became clear that the amount of emissions could be reduced. As described above, according to the present invention, at least a part of the exhaust gas that has been thrown away outdoors is returned to the original working room, so that the amount of new air flowing from outside the working room is reduced, thereby air conditioning. The power consumed by the facility can be greatly reduced. Needless to say, the present invention is applicable not only to a work room where a large amount of dust is generated, such as the semiconductor chip sealing work, but also to other equipment.

DESCRIPTION OF SYMBOLS 1 Circulation type dust collector 2 Work room 3 Building 5 Temperature control and humidity control equipment (air conditioning equipment)
11 Hood (Inlet)
12 Suction Duct 13 Blower 14 Dust Removal Filter 15 Return Duct 15a Opening of Return Duct on Air Return Side 16 Purification Filter 17 Ventilator 18 Heat Insulation Material 20 Power Supply (Charging Process)

Claims (4)

A blower for sucking air in the working chamber;
A dust removal filter that filters air sucked by the blower and removes dust contained in the sucked air;
A return duct for returning at least a portion of the air filtered by the dust filter to the working chamber;
A circulation type dust collector comprising a purification filter provided in the return duct for further filtering air returned to the work chamber.   The circulating dust collector according to claim 1, wherein the purification filter includes at least two types of filters made of different materials.   The circulating dust collector according to claim 1 or 2, wherein at least a part of the return duct is charged so as to electrostatically adsorb floating dust.   4. The total area of the openings for returning air from the return duct to the working chamber is larger than the area of the suction side opening of the blower. 5. Circulation type dust collector.

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