WO1991013700A1 - Method and apparatus for providing substantially constant air flow through the door opening of a fume cupboard - Google Patents
Method and apparatus for providing substantially constant air flow through the door opening of a fume cupboard Download PDFInfo
- Publication number
- WO1991013700A1 WO1991013700A1 PCT/SE1991/000180 SE9100180W WO9113700A1 WO 1991013700 A1 WO1991013700 A1 WO 1991013700A1 SE 9100180 W SE9100180 W SE 9100180W WO 9113700 A1 WO9113700 A1 WO 9113700A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cupboard
- door opening
- exhaust air
- door
- fume
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B15/00—Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area
- B08B15/02—Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area using chambers or hoods covering the area
- B08B15/023—Fume cabinets or cupboards, e.g. for laboratories
Definitions
- the present invention relates to a method and apparatus for providing substantially constant air flow through the door opening of a fume cupboard for laboratory applications and the like, independant of the size of the cupboard door opening.
- the exhaust air flow from a fume cupboard is regulated in two steps, i.e. maximum exhaust air flow when the cupboard door is open, and minimum flow with the door practically closed.
- the cupboard is often made so that the door cannot be closed completely, thus ensuring basic venti lation of the cupboard.
- FIG. 1 schematically illustrating a fume cupboard 2 with an outlet 4 for exhaust air.
- the air flow movin towards the door o enin and throu h the cu board is illustrated with arrows, and if the air flow velocity is too great turbulence of the type illustrated at 6 will occur.
- This turbulence 6 can suck out substances hazardous to health from the fume cupboard, and can be inhaled by the person 8 standing in front of the cupboard door.
- the object of the present invention is to mitigate these defiencies in the previously known art and to provide a method of achieving an apparatus for generating a desired, substantial ⁇ ly constant air flow velocity through the door to a fume cup ⁇ board, irrespective of the size of the aperture the door has been opened to, while the need for over-dimensioning discussed above of the supply and exhaust air systems is eliminated, with accompanying saving in cost.
- the total exhaust air quantity from one or more fume cupboards in a room is measured and the amount of supply air to the room is controlled in response to this amount.
- an excess pressure or a sub-pressure can easily be set in the room, which is often desirable.
- high-risk laboratories e.g. laboratories for AIDS
- clean room laboratories an excess pressure is desirable to avoid contaminants migrating into such a laboratory.
- a further advantage with this embodiment of the invention is that the apparatus can readily be extended with more fume cupboards up to the limit of the capacities of the supply and exhaust air systems without any special setting of the apparatus being required, since there is local control of each room unit.
- the measuring device for the door opening includes an IR transmitter and receiver, as well as a reflector, the transmitter and receiver being fixedly disposed relative the cupboard, with the reflector attached to the door thereof, or vice versa.
- the reflector is then adapted for reflecting light sent from the transmitter to the receiver, the intensity of the reflected light decreasing with increasing distance between transmitter and receiver, on the one hand, and the reflector, on the other hand, there also being a photocell arranged to generate an electrical output signal varying in response to the intensity of the received light. In this way there is obtained simply and reliably a control signed varying continuously with the size of the door opening.
- a still further embodiment of the invention provides for the reflector to move inside a protective tube when the door moves.
- yet another advantageous embodiment of the apparatus in accordance with the invention provides for the regulator to be pneumatically controlled,, and an electropneu atic converter is arranged to convert the output signal from the measuring device for the door opening to a pneumatic signal for controlling the regulator.
- suitable alarms can be arranged to be triggerd, e.g. the size of the air supply to a fume cupboard is incorrect for some reason, or the exhaust air fan unit capacity is exceeded as a result of too many fume cupboards being put into operation simultaneously, or if a cupboard door is left open after work has finished for the day.
- Figure 1 illustrates the turbu ⁇ lence formation that can occur in fume cupboards when the air flow velocity through the cupboard is too high
- Figure 2 illustrates a fume cupboard provided with a measuring device for sensing the door opening such as to generate a corresponding control signal
- Figure 3 illustrates more closely the implement ⁇ ation of the measuring device
- Figure 4 illustrates an embodi ⁇ ment with the reflector arranged in a protective tube
- Figure 5 is a general depiction of an apparatus in accordance with the invention installed in a unit of four rooms.
- FIG 2 there is illustrated a fume cupboard 10 with a raisable and ⁇ lowerable front window or door 12, and from the upper part of the cupboard 10 there is an exhaust air duct 14 provided with a damper.
- a photocell 18 Adjacent the working surface 16 of the cupboard 10 there is a photocell 18 with and IR transmitter and receiver fixedly moun ⁇ ted.
- a reflector 20 is disposed at the lower edge of the door 12, the photocell 18 and the reflector 20 being adapted such that light from the transmitter 22 is reflected towards the receiver 24 of the photocell 18, see Figure 3.
- the intensity of the received IR signal decreases as the distance between the photocell 18 and the reflector 20 increas ⁇ es, the photocell sending an output signal which is proportional to the intensity of the received IR light.
- an electrical output signal from the photocell 18 which is proportional to the distance between the photocell and the reflector, i.e. proportional to the opening of the door 12.
- the measuring device provided thus can suitable be implemented such that the photocell 18 sens an electrical output signal varying continuously from 0 to 10 V when the opening of the door 12 varies from 400 - 0 mm.
- the cupboard door is not often closed completely, and there is a minimum opening, e.g. 5 cm, which ensures basic ventilation.
- the door opening may vary from 50 - 450 mm, and constant air flow velocity through the door opening is ensured by the apparatus in accordance with the invention.
- the reflector 20 is subjected to dirtying, thus causing its reflective power and consequently the reflected signal to de ⁇ crease.
- the reflector is suitably arranged in a protective tube 26, parallell to the side edge of the door 12, a longitudinal slot 28 being made in its side facing towards the door 12, a holder arm 30 for the reflector 20 being disposed in the slot for movement along it, see Figure 4.
- the ouput signal from the photocell 18 is converted in an electropneumatic con ⁇ verter 32 to a pneumatic signal for controlling an exhaust air regulator 34 on the exhaust air duct 14 of the cupboard 10, see Figure 2.
- Pneumatic control of the regulator 34 is necessary to obtain sufficiently rapid setting of the exhaust air flow when the door 12 is pulled up or down.
- the setting time from maximum to minimum air flow, or vice versa, should be about 3 - 5 sees.
- Flow variators can be used as regulators, and they are sold by the Applicant with the denotation EM(JP) (BC) .
- the damper blade 36 is suitably made from an acid-resistant material.
- FIG. 5 there is shown an apparatus in accordance with the invention installed in a unit of four rooms, each of which contains four fume cupboards 10.
- An exhaust air regulator 34 is arranged in the exhaust air duct 14 from each of the cupboards 10.
- the exhaust air is extracted from each room via a common plenum duct 38, in which a volume meter 40 is disposed.
- This meter suitably comprises a so-called volume measuring flange.
- the plenum ducts 38 merge into a common main plenum duct 42, provided with an exhaust air fan unit 44.
- an air supply fan unit 46 disposed for feeding an air supply plenum duct 48, common to the whole unit, from which supply air ducts 50 lead to each of the rooms.
- an air supply fan unit 46 disposed for feeding an air supply plenum duct 48, common to the whole unit, from which supply air ducts 50 lead to each of the rooms.
- a volume meter 52 and a regulator 54.
- the volume meters 52 are suitably volume measur ⁇ ing flanges of the same kind as in the exhaust plenum ducts and the regulators 54 are the same kind as the regulators in the ex ⁇ haust air ducts 14 of the fume cupboards 10.
- Supply of air to each of the rooms suitably takes place using a supply air means 56 disposed in the ceiling of the rrspective room, and adapted such that a draught-free supply of air with a variable flow is obtained within the desired working volume. It is advantageous that the air supply takes place obliquely from above, since the bodily extension of persons working at the cupboards is less from above then seen from one side, thus reducing the risk of turbulence in the air supplied.
- the volume meter 52 and regulator 54 in the duct 50 to each room are controlled from the volume meter 40 in the appropriate plenum duct 38.
- the air supply such as to respond to the exhaust air flow in this way, a desired air flow velocity through the cup ⁇ boards 10 is maintained the whole time.
- Air velocities of the order of magnitude of 0,4 - 0,7 m/s are suitable in the door opening.
- the apparatus in accordance with the invention is furthermore suitably implemented such that the exhaust air regulator opens to a maximum if the control signal fails.
- the described embodiment example is implemented with respect to regulation so that increasing exhaust air flow is provided for a decreasing control pressure signal.
- the photocell can also be disconnected by a switch simultaneously as the exhaust air flow increases to its maximum value.
- the fans 44 on the exhaust air side are suitably surface treated to withstand corrosive gases.
- the fan blades can therefore be epoxi anodised.
- the apparatus in accordance with the invention can with advantage be” provided with different alarms, such as an alarm triggered on detection of a too small amount of air in the fume cupboard, or when the fan unit capacity is exceeded, i.e. too many cupboards open at the same time, or when cupboard doors have been left open after work is finsished for the day.
- the alarm can be both visual and acoustic. When an alarm acknow ⁇ ledgement has been made, the acoustic alarm can be disconnected, although the visual alarm indication continues to be illuminated until the fault is remedied, this indication then being exting ⁇ uished by a further alarm acknowledgement.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP91905968A EP0518970B1 (en) | 1990-03-08 | 1991-03-08 | Method and apparatus for providing substantially constant air flow through the door opening of a fume cupboard |
DE69110454T DE69110454T2 (en) | 1990-03-08 | 1991-03-08 | METHOD AND DEVICE FOR CREATING A SUBSTANTIALLY CONSTANT AIRFLOW THROUGH THE DOOR OPENING OF A SMOKING BOX. |
NO923482A NO174838C (en) | 1990-03-08 | 1992-09-07 | Method and apparatus for providing substantially constant air flow through the doorway of a vent |
FI924008A FI101269B (en) | 1990-03-08 | 1992-09-08 | Method and apparatus for providing a substantially constant flow of air through a hatch into a fume cupboard |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9000821-0 | 1990-03-08 | ||
SE9000821A SE468118B (en) | 1990-03-08 | 1990-03-08 | PROCEDURE AND DEVICE TO ACHIEVE SIGNIFICANT CONSTANT AIR FLOW THROUGH THE DOOR OF A TRANSFER |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991013700A1 true WO1991013700A1 (en) | 1991-09-19 |
Family
ID=20378796
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1991/000180 WO1991013700A1 (en) | 1990-03-08 | 1991-03-08 | Method and apparatus for providing substantially constant air flow through the door opening of a fume cupboard |
Country Status (10)
Country | Link |
---|---|
EP (1) | EP0518970B1 (en) |
AT (1) | ATE123673T1 (en) |
AU (1) | AU7494391A (en) |
DE (1) | DE69110454T2 (en) |
DK (1) | DK0518970T3 (en) |
ES (1) | ES2076524T3 (en) |
FI (1) | FI101269B (en) |
NO (1) | NO174838C (en) |
SE (1) | SE468118B (en) |
WO (1) | WO1991013700A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0541865A1 (en) * | 1990-09-28 | 1993-05-19 | Landis & Gyr Powers, Inc. | Apparatus for determining the position of a moveable structure along a track |
EP0541863A1 (en) * | 1990-09-28 | 1993-05-19 | Landis & Gyr Powers, Inc. | Laboratory fume hood control apparatus having improved safety considerations |
US6935943B2 (en) | 2002-10-10 | 2005-08-30 | Honeywell International Inc. | Wireless communication for fume hood control |
EP2175181A2 (en) * | 2008-10-08 | 2010-04-14 | TROX GmbH | Throttle element for ventilation safety devices, in particular for laboratory extractors |
US9694398B2 (en) | 2012-10-31 | 2017-07-04 | Honeywell International Inc. | Controlling a fume hood airflow using an image of a fume hood opening |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995013146A1 (en) * | 1993-11-09 | 1995-05-18 | Stasch Karl Heinz | A computerized ventilation system |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4160407A (en) * | 1977-11-18 | 1979-07-10 | Bell Telephone Laboratories, Incorporated | Ventilating system |
SE429013B (en) * | 1980-06-19 | 1983-08-08 | Ulf Torsten Jonsson | Method of controlling, regulating and indicating the ventilation air in ventilated spaces such as an exhaust hood and arrangement for carrying out the method |
GB2129544A (en) * | 1982-10-30 | 1984-05-16 | Cygnet Joinery Limited | Fume cupboard |
GB2222705A (en) * | 1988-05-19 | 1990-03-14 | Thomas Arthur Wisbey Wheeler | Reduced pressure enclosure |
-
1990
- 1990-03-08 SE SE9000821A patent/SE468118B/en not_active IP Right Cessation
-
1991
- 1991-03-08 AT AT91905968T patent/ATE123673T1/en active
- 1991-03-08 DK DK91905968.3T patent/DK0518970T3/en active
- 1991-03-08 EP EP91905968A patent/EP0518970B1/en not_active Expired - Lifetime
- 1991-03-08 ES ES91905968T patent/ES2076524T3/en not_active Expired - Lifetime
- 1991-03-08 AU AU74943/91A patent/AU7494391A/en not_active Abandoned
- 1991-03-08 DE DE69110454T patent/DE69110454T2/en not_active Expired - Fee Related
- 1991-03-08 WO PCT/SE1991/000180 patent/WO1991013700A1/en active IP Right Grant
-
1992
- 1992-09-07 NO NO923482A patent/NO174838C/en not_active IP Right Cessation
- 1992-09-08 FI FI924008A patent/FI101269B/en active IP Right Revival
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4160407A (en) * | 1977-11-18 | 1979-07-10 | Bell Telephone Laboratories, Incorporated | Ventilating system |
SE429013B (en) * | 1980-06-19 | 1983-08-08 | Ulf Torsten Jonsson | Method of controlling, regulating and indicating the ventilation air in ventilated spaces such as an exhaust hood and arrangement for carrying out the method |
GB2129544A (en) * | 1982-10-30 | 1984-05-16 | Cygnet Joinery Limited | Fume cupboard |
GB2222705A (en) * | 1988-05-19 | 1990-03-14 | Thomas Arthur Wisbey Wheeler | Reduced pressure enclosure |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0541865A1 (en) * | 1990-09-28 | 1993-05-19 | Landis & Gyr Powers, Inc. | Apparatus for determining the position of a moveable structure along a track |
EP0541863A1 (en) * | 1990-09-28 | 1993-05-19 | Landis & Gyr Powers, Inc. | Laboratory fume hood control apparatus having improved safety considerations |
US6935943B2 (en) | 2002-10-10 | 2005-08-30 | Honeywell International Inc. | Wireless communication for fume hood control |
US6960126B2 (en) * | 2002-10-10 | 2005-11-01 | Honeywell International Inc. | Wireless communication for fume hood control |
EP2175181A2 (en) * | 2008-10-08 | 2010-04-14 | TROX GmbH | Throttle element for ventilation safety devices, in particular for laboratory extractors |
EP2175181A3 (en) * | 2008-10-08 | 2010-10-27 | TROX GmbH | Throttle element for ventilation safety devices, in particular for laboratory extractors |
US9694398B2 (en) | 2012-10-31 | 2017-07-04 | Honeywell International Inc. | Controlling a fume hood airflow using an image of a fume hood opening |
US11951514B2 (en) | 2012-10-31 | 2024-04-09 | Honeywell International Inc. | Controlling a fume hood airflow using an image of a fume hood opening |
Also Published As
Publication number | Publication date |
---|---|
FI101269B1 (en) | 1998-05-29 |
EP0518970B1 (en) | 1995-06-14 |
NO923482L (en) | 1992-11-06 |
SE9000821D0 (en) | 1990-03-08 |
ATE123673T1 (en) | 1995-06-15 |
FI924008A (en) | 1992-09-08 |
NO174838C (en) | 1994-07-20 |
SE9000821L (en) | 1991-09-09 |
EP0518970A1 (en) | 1992-12-23 |
NO923482D0 (en) | 1992-09-07 |
AU7494391A (en) | 1991-10-10 |
DE69110454T2 (en) | 1995-12-14 |
FI924008A0 (en) | 1992-09-08 |
DK0518970T3 (en) | 1995-10-09 |
SE468118B (en) | 1992-11-09 |
FI101269B (en) | 1998-05-29 |
NO174838B (en) | 1994-04-11 |
DE69110454D1 (en) | 1995-07-20 |
ES2076524T3 (en) | 1995-11-01 |
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