Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
  • F24F13/28—Arrangement or mounting of filters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/0002—Casings; Housings; Frame constructions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/0084—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours provided with safety means
  • B01D46/0097—Special means for preventing bypass around the filter, i.e. in addition to usual seals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/42—Auxiliary equipment or operation thereof
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F2221/00—Details or features not otherwise provided for
  • F24F2221/14—Details or features not otherwise provided for mounted on the ceiling

Definitions

• the present invention relates to an air filter housing comprising a filter body and a tube connecting the up-stream side of the filter body to the downstream side thereof, said tube passing through the wall of the filter housing at one or more locations.
• outside air is delivered to the room via air filters and also exhausted from the room via air filters. Some of the exhausted air is usually recirculated.
• the amount of air delivered to the room is depending on the necessary level of cleanness of the air and is generally between twenty to four hundred times the volume of the room per hour.
• the air filters are contained within filter housings generally made of painted steel, stainless steel, aluminium or plastic materials. The connection between the filter and the filter housing must be leakproof so that all outside air and/or recirculated air passes through the filter and also the connection between the filter leading to or from a filter housing must of course also be leakproof.
• the inlet filter or filters are mounted in the ceiling of the room and the exhaust filter or filters are mounted in a wall near the floor of the room.
• the inlet filter has a tube of plastic material leading from the inside of the filter housing at a location upstream of the air filter body, which is mounted in the housing in a leakproof manner, to a location within the mouth of the filter housing downstream of the air filter body.
• a tube can be used for measuring the pressure drop over the filter and is also needed in certain cases for leak test equipment that needs an upstream connection.
• FIG 1 a part of a known filter housing H containing a filter body B and a tube T is schematically shown. As is evident from this Figure the tube T passes through the wall of the filter housing H at two locations I and II. The tube T is at these locations attached to the housing by connections C comprising nuts, special screw and gaskets.
• a plug P is closing the opening thereof.
• the mounting thereof In order to ensure leak-tightness of the connections C, the mounting thereof must be done very carefully and is therefore time consuming. Furthermore, after full assembly of the filter housing it is not in practice possible to tighten these connections.
• a further problem is that since the tube is of flexible material it can be pinched in the piece outside of the filter housing, i.e. the piece between the two connections C. Since there is no access to said piece of tube when the filter housing has been mounted in the ceiling such a pinched piece can not be repaired or replaced.
• the objective of the present invention is to improve an air filter housing of the above-mentioned type so that the drawbacks discussed above are eliminated.
• an air filter housing comprising a filter body and a tube connecting the up-stream side of the filter body to the downstream side thereof, said tube passing through the wall of the filter housing at one or more locations, characterised in that said tube is permanently and air-tightly secured to the wall of the filter housing at each location where it passes therethrough.
• said tube is made of two parts, a first part of rigid material and a second part of plastic material attached to the downstream end of the first part in an air-tight manner.
• the first part of the tube is made of stainless steel.
• the tube has preferably such a length that the downstream end of the first part of said tube is located downstream of the filter body.
• said tube is welded to the filter housing and a downstream end portion of said first part of said tube is perpendicular to the direction of an air flow through the filter.
• FIG. 1 schematically shows a part of an air filter according to prior art with a front wall of a filter housing removed
• Fig. 2 schematically shows an air filter housing according to a preferred embodiment of the present invention mounted in the ceiling of a room
• Fig. 3 schematically shows a part of the filter housing in Figure 2 with a front portion of the housing removed
• Fig. 4 schematically shows a view of the filter housing in Figure 3 taken along line IV-IV in Figure 3.
• an air filter housing 1 is schematically shown mounted in the ceiling of a clean room.
• a duct 2 leads out-side air and recirculated air into the filter housing.
• the filter housing 1 is attached to the ceiling 3, usually made of concrete, by four screws 4 or the like, of which two are shown in Figure 2.
• the screws 4 having outer threads in the lower end portions thereof co- operating with nuts 5 for enabling adjustment of position of the filter housing.
• the clean room has a false ceiling 6, the plane of which shall be coincident to the plane of the mouth of the air filter housing. Said false ceiling is sealed to a flange projecting out from the mouth of the filter housing 1. If the mouth of the filter housing is not flush with the false ceiling 6, the position thereof is adjusted by manipulating the nuts 5.
• the filter housing comprises an upper part 7 and a lower part 8, in which a filter body 9 (not shown in Figure 2) is supported.
• a grid (not shown) for directing the flow of air from the filter into the room is also supported in the lower part 8 near the mouth of the filter.
• the air filter housing so far described and its components including the filter body is of conventional design and could be any known air filter suitable for clean room application.
• the air filter housing also includes a tube 10 according to the present invention which connects the upper part 7 being located upstream of the filter body 9 with the downstream end of the filter housing 1.
• This tube 10 consists of a first part 11 and a second part 12.
• the first part 11 is made of rigid material and has an upper end passing through a side wall 13 of the upper part 7 of the filter housing 1.
• the first part 11 of the tube 10 is curved and passes from the side wall 13 of the upper part 7 of the filter housing through a bottom wall 14 of the lower part 8 passing along a side of the filter body 9, as can be seen in Figure 3.
• the second part 12 is a plastic tube.
• the first part 11 of the tube 10 is permanently attached to side wall 13 and bottom wall 14 of the filter housing.
• the permanent connection between the fist part 11 and the respective wall 13,14 of the filter housing should also be air-tight so that no "dirty" air from the upstream portion of the filter housing can leak into the clean room, i.e. all air should pass through the filter body 9.
• the permanent connection is preferably made by welding but could also be made by soldering or gluing.
• the first part 10 is extended beyond filter body 9 in the downstream direction.
• the first part 11 is curved so that a downward end portion thereof is extended in a direction perpendicular to the flow of air through the filter, as best seen in Figure 4. If an operator pulls the second part 12 out of the filter housing in order to couple the free end of the second part to a test equipment, the pulling force will thereby be directed perpendicular to the portions of the first and second parts that are connected to each other. The risk that the first and second parts 11, 12 will disengage from each other is therefore greatly reduced compared to a case when the pulling force act on portions of the first and second parts that are connected to each other and directed in a downward direction.
• the material in the first part 11 of the tube 10 should preferably be compatible with the material in the filter housing from a welding point of view.
• the filter housing 1 is made of metal
• the first part 11 should also be made of metal.
• the first part 11 should to advantage be made of stainless steel in order to prevent the creating of rust.
• the filter housing is made of plastic also the first part 11 should be made of plastic.
• a "permanent connection” is in this application meant a connection or join which can not be broken without at the same time damage the tube 10 or a wall of the filter housing. Such a connection can resist a force of at least 50N.
• the connection between the pressure drop tube is connected or joined to the walls of the filter housing by soldering or gluing
• the material of the tube need not be compatible with the material in the filter housing from a welding point of view.
• the downstream end portion of the first part of the tube need not exactly be perpendicular to the vertical air flow direction but can form an angle of 0-20 degrees to the horizontal. In such a case, the angle between the two straight portions of the first part of the pressure drop tube is preferably greater than 90 degrees.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=39681935

Family Applications (1)

Country Status (2)

Family Cites Families (3)

• 2007
  • 2007-02-05 WO PCT/SE2007/050063 patent/WO2008097143A1/en not_active Ceased
  • 2007-02-05 EP EP07709456.3A patent/EP2125155A4/de not_active Withdrawn

Non-Patent Citations (1)

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