EP0157774A1 - Dental fume cupboard - Google Patents

Dental fume cupboard

Info

Publication number
EP0157774A1
EP0157774A1 EP19830903772 EP83903772A EP0157774A1 EP 0157774 A1 EP0157774 A1 EP 0157774A1 EP 19830903772 EP19830903772 EP 19830903772 EP 83903772 A EP83903772 A EP 83903772A EP 0157774 A1 EP0157774 A1 EP 0157774A1
Authority
EP
European Patent Office
Prior art keywords
cabinet
air
door
storage cabinet
storage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19830903772
Other languages
German (de)
French (fr)
Inventor
Michael George Ridley
John Wilson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0157774A1 publication Critical patent/EP0157774A1/en
Withdrawn legal-status Critical Current

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
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C19/00—Dental auxiliary appliances
    • A61C19/007—Dust removing devices on working places in dental laboratories, e.g. working by suction

Definitions

  • This invention relates to a storage cabinet for fumes and toxic vapour producing materials.
  • the invention finds particular application in the prevention of mercury vapour contamination within dental surgeries.
  • the invention is not limited to such an application, and it is ' envisaged that it may be used for storing- a range of fume producing materials.
  • considerable amounts of mercury are both stored and manipulated in the production of dental amalgams.
  • Liquid mercury has a vapour pressure, thus some toxic mercury vapour tends to escape into the surgery atmosphere creating a health hazard for dentist, dental staff and patient alike.
  • a storage cabinet comprising a body of the cabinet; an aperture in the cabinet body for access to the interior of the cabinet? a door movably mounted on the body of the cabinet for closing the access aperture; characterised in that the cabinet further comprises means for circulating air within the storage cabinet and a fume and/or toxic vapour absorbing filter through which air within the cabinet is circulated for absorption of toxic vapour.
  • the body of the cabinet is substantially airtight and the door is sealed to the body when closed.
  • the door itself is preferably curved and pivoted about a point eccentric from the centre of the curve whereby in closing, sealing elements are closed onto as opposed to being merely slid along. Elastomeric sealing elements may be provided on the door or on the cabinet's body.
  • the air circulation means is preferably arranged to induce a swirling action of the air in the cabinet to effect thorough mixing of the air whereby no stagnation pockets form in which toxic vapours can accumulate.
  • the air circulation means is preferably provided with an elongate exit slot, or series of aligned exit apertures in the form of holes or short slots, for directing filtered air across the aperture in a so-called "air curtain".
  • a pump included in the air circulating means may be provided either within the cabinet body or outside the body.
  • the pump's motor is provided outside the body with an impeller provided within the body.
  • the impeller, the pump, associated controls and a portion of a wall of the cabinet comprise a replaceable unit.
  • the filter also is preferably a replaceable unit at the input to the air circulating means.
  • the motor is provided with a speed control, or is alternatively a two speed motor, whereby when the door is closed, the motor runs at slow speed causing a slow circulation of air in the cabinet and when the door is open the motor runs at a fast speed causing the "air curtain" to be more intense.
  • a speed control or is alternatively a two speed motor, whereby when the door is closed, the motor runs at slow speed causing a slow circulation of air in the cabinet and when the door is open the motor runs at a fast speed causing the "air curtain" to be more intense.
  • This has dual advantages in that should vapour from the cabinet escape it will be in the first place predominantly filtered air and secondly it will be fast moving and hence quickly dispersed.
  • the second advantage is that during operations in the cabinet releasing toxic vapour, such as the dispensing of mercury, the vapour will be rapidly drawn into the filter.
  • the motor is slowed- when the door is closed to avoid the noise, power consumption and wear on the circulating means associated with the high speed.
  • Figure 1 is a perspective view of a storage cabinet of the invention
  • Figure 2 is a front view of the cabinet when closed
  • Figure 3 is a cross-sectional front view on the line
  • Figure 4 is a cross-sectional end view on the line IV -
  • Figure 6 is a perspective view of the air circulating means in the cabinet
  • Figure 7 is an end view of the cabinet in the direction of the arrow VII in Figure 2;
  • OMPI Figure 8 is a view similar to Figure 7 with a motor housing removed;
  • Figure 9 is a plan view of the replaceable pump unit;
  • Figure 10 is a scrap view in the direction of the arrow X in Figure 5;
  • Figure 11 is a scrap view similar to Figure 10 of a modified embodiment.
  • Figure 12 is a cross-sectional view of a filter unit for the cabinet.
  • the illustrated storage cabinet has a body 11 fabricated from 5mm Acrylic sheet.
  • a door 12 is hinged at end walls 13, 14 of the cabinet by means of nylon bolts and bushes 15 passing through the end walls and wings 16 bonded to a transparent front panel 17 of the door.
  • the front panel 17 is cir ⁇ cularly curved with a centre of curvature 18, see Figures 4 & 5.
  • the door which is provided with a knob 19 is closed elastomeri ⁇ sealing strips 20, 21, 22 along the inside end and rear edges of the front door panel 17 abut the top edges 23, 24 of the end walls 13, 14 and the top side 25 of the front edge of a top wall of the cabinet.
  • a further sealing strip 26 on the front edge of the door panel abuts a lip 27 provided at the top front edge of a front wall 28 of the cabinet body.
  • the bolts 15 are provided above and behind the centre of curvature 18 whereby they are eccentric from the curve of the front panel.
  • This ar ⁇ rangement causes the sealing elements to lift away from their abutment surfaces on the cabinet body when the door is opened, thus avoiding wear of the elements which would result from pure sliding movement of the sealing elements over their abutment surfaces.
  • the opened position of the door is shown in Figure 4 wherein the door rests on stops 29 at the back of the cabinet.
  • the sealing elements could alternatively be provided on the body at the abutment surfaces.
  • OMH nylon bolts 15 could be sealed to the end walls 13, 14. However in practice this is found not to be necessary.
  • the cabinet body has a rectangular base 30.
  • An air duct 31 extends in the corner between the base and both the end wall 13 and the front wall 28.
  • the air duct has up ⁇ right walls 32, 33, parallel respectively with the end wall 13 and the front wall 28, and tops 34, 35.
  • the top 34 has a front lip and defines between the end wall 13 and a con ⁇ tinuation of the upright wall 32 a toxic material container storage, i.e. a mercury container storage where the cabinet is for use by dentists.
  • the top 35 has an upturned rear rim 36 and defines an instrument storage.
  • An air curtain slot 37 described in more detail below with reference to Figure 10 is defined between the rim 36 and both the upper edge of the wall 33, which is turned backwards and lies under the rim 36, and the front edge of the top 34.
  • the rear edge of the top 34 is turned up and the upright wall 32 is continued up and turned over to define a space for an impeller 39 of an air circulating pump.
  • the turned-over top of the wall 32 supports an electric socket 38 for apparatus such as an amalgamator (not shown) stored on the base 30.
  • a replace ⁇ able filter 40 described in more detail below with reference to Figure 12 is supported by three screws 41 at an aperture 42 in the wall 32.
  • a scroll 43 of formed styrene is fitted with an inlet coincident with the aperture 42 and an outlet aligned with the air duct 31.
  • the impeller 39 is mounted on the shaft of a motor 44 itself mounted on a moulded-styrene replaceable wall portion 46 bolted across an aperture 47 in the end wall 13. Sealing of the aperture 47 is effected by close fit ⁇ ting of the moulded wall portion 46, although an O-ring seal could be provided. An O-ring seal, not shown, is provided between the shaft 44 and the moulded portion 46.
  • An elec- tronic speed control unit 48 is mounted on the moulded portion 46 as is a switch 49.
  • a pivot arm 50 extends beyond the switch for actuation thereof by a cam 51 on the door wing 16, the arrangement being such that when the door is open the speed control is switched for the motor to run at its full speed and when the door is closed the speed control is switched for the motor to run at a slow speed.
  • the actual slow speed can be set with a rheostat in the speed control.
  • the moulded portion 46, impeller 39, motor 44, speed control 48 and switch 49 are all replaceable as a single unit.
  • a housing 52 covers the motor and its associated components.
  • Air circulation is through the filter 40, the impeller 39, along the duct 31 and out of the slot 37.
  • the slot is oriented to direct an air curtain across an access aperture 53 in the body of the cabinet which is normally closed by the door 12.
  • the slot tapers and is narrower at the end thereof adjacent the end wall 14; since this end is remote from the impeller 39 the static pressure head in the air duct at this end is highest.
  • a number, three as shown, of partition members 54 in the air duct defining subsidiary passageways lead air to a number of aligned air outlets 55. In this alternative there is no outlet directed towards the container storage at top 34.
  • the generally circular filter 40 as shown in cross- section in Figure 12 comprises a pad 56 of activated carbon in a foam structure for absorbing mercury vapour, or other fumes or toxic vapours, sandwiched between on either side an inner scrim layer 57 and an outer open dust filter 58 of non-woven fabric.
  • the sandwich structure is retained together by a pair of formed styrene rings 59, 60 which are clipped or glued together.
  • Each ring has an inwardly directed flange 61, 62 between which the edge of the sand-
  • the outer ring 59 has a rim 63 having three cut outs allowing passage of the heads of the screws 41 on fitting of the filter. It is secured by twisting to bring the heads over the rim.
  • the inner ring 5 61 bears against the end wall 13 with a small rim 64 en ⁇ gaging in the aperture 42.
  • the air therein is filtered by means of repeated passes through the filter 40.
  • the efficiency of the filter 40 is not 0 100%, however by the time the air in the cabinet has passed repeatedly through the filter, the level of fumes and toxic vapours in the atmosphere of the cabinet interior is sub ⁇ stantially reduced to zero or immeasurably small concen ⁇ tration levels. 5
  • the motor and impeller is capable of passing the entire air volume of the cabinet interior through the filter 40 three times per minute.
  • An extremely severe test of the cabinet was carried out by placing 500 mg. (a o massive amount compared to day-to-day spillages or droplets) of liquid mercury in an open dish placed on the base 30.
  • the internal temperature of the cabinet was 23°C whilst vapourisation of the mercury proceeded.
  • the resulting level of mercury vapour contamination vastly exceeded the 5 maximum reading 2.00 mg.Hg/cubic meter of the available mercury vapour detector. With the door 12 closed, the measured level of mercury vapour contamination was reduced as follows:-
  • the cabinet provides a safe environment for working with toxic vapour producing sub- stances such as mercury. Spillages in the cabinet are contained. The vapour is filtered. Possibly contaminated instruments and the like can be stored.

Landscapes

  • Ventilation (AREA)

Abstract

Un coffret pour stocker un matériau produisant des vapeurs toxiques possède une porte (12) pouvant se fermer hermétiquement. Un dispositif de circulation d'air (31, 39, 44) fait passer de l'air dans le coffret par une filtre remplaçable (40) afin d'absorber la vapeur. L'air sort du dispositif de circulation sous la forme d'un rideau d'air (65) par une ouverture (53) d'accès au coffret. Une pompe (39, 44) possède deux vitesses de circulation d'air, lente lorsque la porte (12) est fermée et rapide lorsque la porte (12) est ouverte. Il est possible de remplacer des composants actifs de la pompe en tant qu'unités.A cabinet for storing material producing toxic vapors has a door (12) which can be closed hermetically. An air circulation device (31, 39, 44) passes air into the cabinet through a replaceable filter (40) to absorb the vapor. The air leaves the circulation device in the form of an air curtain (65) through an opening (53) for access to the cabinet. A pump (39, 44) has two air circulation speeds, slow when the door (12) is closed and fast when the door (12) is open. Active pump components can be replaced as units.

Description

DERTAL FUME CUPBOARD
This invention relates to a storage cabinet for fumes and toxic vapour producing materials. The invention finds particular application in the prevention of mercury vapour contamination within dental surgeries. However, the invention is not limited to such an application, and it is ' envisaged that it may be used for storing- a range of fume producing materials. in dental surgeries, for example, considerable amounts of mercury are both stored and manipulated in the production of dental amalgams. Liquid mercury has a vapour pressure, thus some toxic mercury vapour tends to escape into the surgery atmosphere creating a health hazard for dentist, dental staff and patient alike.
It has been known to store mercury and locate devices such as amalgam mixing machines within conventional fume cabinets. However, such cabinets suffer from various disadvantages. An exhaust system as is required in a conventional fume cabinet to exhaust vapours to the atmosphere is expensive to install. Such an exhaust system can also be expensive to operate and furthermore is often unsightly.
When such a conventional fume 'cabinet is opened to permit access to the cabinet interior, there- is a tendency for some small amount of the vapour within the fume cabinet interior to escape into the surgery atmosphere via an access opening..
Experiments were conducted with cabinets exhausting to the ambient atmosphere through a filter. However these were unsatisfactory due to the inability of the-filters to absorb all the mercury vapour passing through the filter.
The object of the present invention is to overcome, or. substantially ameliorate the mentioned disadvantages and to ' provide an improved storage cabinet. According to the invention there is provided a storage cabinet comprising a body of the cabinet; an aperture in the cabinet body for access to the interior of the cabinet? a door movably mounted on the body of the cabinet for closing the access aperture; characterised in that the cabinet further comprises means for circulating air within the storage cabinet and a fume and/or toxic vapour absorbing filter through which air within the cabinet is circulated for absorption of toxic vapour. Normally the body of the cabinet is substantially airtight and the door is sealed to the body when closed. However the degree of airtightness need not be such that all fitting apertures in the body are totally hermetically sealed. The door itself is preferably curved and pivoted about a point eccentric from the centre of the curve whereby in closing, sealing elements are closed onto as opposed to being merely slid along. Elastomeric sealing elements may be provided on the door or on the cabinet's body.
The air circulation means is preferably arranged to induce a swirling action of the air in the cabinet to effect thorough mixing of the air whereby no stagnation pockets form in which toxic vapours can accumulate.
Further, the air circulation means is preferably provided with an elongate exit slot, or series of aligned exit apertures in the form of holes or short slots, for directing filtered air across the aperture in a so-called "air curtain".
A pump included in the air circulating means may be provided either within the cabinet body or outside the body. In the preferred embodiment, the pump's motor is provided outside the body with an impeller provided within the body. Although other arrangements are possible, in the preferred arrangement the impeller, the pump, associated controls and a portion of a wall of the cabinet comprise a replaceable unit. The filter also is preferably a replaceable unit at the input to the air circulating means.
Conveniently the motor is provided with a speed control, or is alternatively a two speed motor, whereby when the door is closed, the motor runs at slow speed causing a slow circulation of air in the cabinet and when the door is open the motor runs at a fast speed causing the "air curtain" to be more intense. This has dual advantages in that should vapour from the cabinet escape it will be in the first place predominantly filtered air and secondly it will be fast moving and hence quickly dispersed. The second advantage is that during operations in the cabinet releasing toxic vapour, such as the dispensing of mercury, the vapour will be rapidly drawn into the filter. The motor is slowed- when the door is closed to avoid the noise, power consumption and wear on the circulating means associated with the high speed.
The switching from high to low speed is preferably achieved by means of a cam provided on the door and co¬ operating with a switch during opening of the door. To help understanding of the invention, a specific embodiment thereof will now be described with reference to the accompanying drawings in which:
Figure 1 is a perspective view of a storage cabinet of the invention; Figure 2 is a front view of the cabinet when closed; Figure 3 is a cross-sectional front view on the line
III - III in Figure 5 of the cabinet when open;
Figure 4 is a cross-sectional end view on the line IV -
IV in Figure 2 of the cabinet when closed; Figure 5 is a cross-sectional end view on the line V -
V in Figure 3 of the cabinet when open;
Figure 6 is a perspective view of the air circulating means in the cabinet;
Figure 7 is an end view of the cabinet in the direction of the arrow VII in Figure 2;
OMPI Figure 8 is a view similar to Figure 7 with a motor housing removed;
Figure 9 is a plan view of the replaceable pump unit; Figure 10 is a scrap view in the direction of the arrow X in Figure 5;
Figure 11 is a scrap view similar to Figure 10 of a modified embodiment; and
Figure 12 is a cross-sectional view of a filter unit for the cabinet. Referring first to Figures 1 to .5, the illustrated storage cabinet has a body 11 fabricated from 5mm Acrylic sheet. A door 12 is hinged at end walls 13, 14 of the cabinet by means of nylon bolts and bushes 15 passing through the end walls and wings 16 bonded to a transparent front panel 17 of the door. The front panel 17 is cir¬ cularly curved with a centre of curvature 18, see Figures 4 & 5. When the door which is provided with a knob 19 is closed elastomeriσ sealing strips 20, 21, 22 along the inside end and rear edges of the front door panel 17 abut the top edges 23, 24 of the end walls 13, 14 and the top side 25 of the front edge of a top wall of the cabinet. A further sealing strip 26 on the front edge of the door panel abuts a lip 27 provided at the top front edge of a front wall 28 of the cabinet body. The bolts 15 are provided above and behind the centre of curvature 18 whereby they are eccentric from the curve of the front panel. This ar¬ rangement causes the sealing elements to lift away from their abutment surfaces on the cabinet body when the door is opened, thus avoiding wear of the elements which would result from pure sliding movement of the sealing elements over their abutment surfaces. The opened position of the door is shown in Figure 4 wherein the door rests on stops 29 at the back of the cabinet. The sealing elements could alternatively be provided on the body at the abutment surfaces. For complete airtightness of the cabinet, the
OMH nylon bolts 15 could be sealed to the end walls 13, 14. However in practice this is found not to be necessary.
The cabinet body has a rectangular base 30. An air duct 31 extends in the corner between the base and both the end wall 13 and the front wall 28. The air duct has up¬ right walls 32, 33, parallel respectively with the end wall 13 and the front wall 28, and tops 34, 35. The top 34 has a front lip and defines between the end wall 13 and a con¬ tinuation of the upright wall 32 a toxic material container storage, i.e. a mercury container storage where the cabinet is for use by dentists. The top 35 has an upturned rear rim 36 and defines an instrument storage. An air curtain slot 37 described in more detail below with reference to Figure 10 is defined between the rim 36 and both the upper edge of the wall 33, which is turned backwards and lies under the rim 36, and the front edge of the top 34. At the rear of the cabinet, the rear edge of the top 34 is turned up and the upright wall 32 is continued up and turned over to define a space for an impeller 39 of an air circulating pump. The turned-over top of the wall 32 supports an electric socket 38 for apparatus such as an amalgamator (not shown) stored on the base 30. A replace¬ able filter 40 described in more detail below with reference to Figure 12 is supported by three screws 41 at an aperture 42 in the wall 32.
In the impeller space a scroll 43 of formed styrene is fitted with an inlet coincident with the aperture 42 and an outlet aligned with the air duct 31. Referring now to Figures 8 and 9, the impeller 39 is mounted on the shaft of a motor 44 itself mounted on a moulded-styrene replaceable wall portion 46 bolted across an aperture 47 in the end wall 13. Sealing of the aperture 47 is effected by close fit¬ ting of the moulded wall portion 46, although an O-ring seal could be provided. An O-ring seal, not shown, is provided between the shaft 44 and the moulded portion 46. An elec- tronic speed control unit 48 is mounted on the moulded portion 46 as is a switch 49. A pivot arm 50 extends beyond the switch for actuation thereof by a cam 51 on the door wing 16, the arrangement being such that when the door is open the speed control is switched for the motor to run at its full speed and when the door is closed the speed control is switched for the motor to run at a slow speed. The actual slow speed can be set with a rheostat in the speed control. The moulded portion 46, impeller 39, motor 44, speed control 48 and switch 49 are all replaceable as a single unit. A housing 52 covers the motor and its associated components.
Air circulation is through the filter 40, the impeller 39, along the duct 31 and out of the slot 37. The slot is oriented to direct an air curtain across an access aperture 53 in the body of the cabinet which is normally closed by the door 12. As may be seen in Figure 10, the slot tapers and is narrower at the end thereof adjacent the end wall 14; since this end is remote from the impeller 39 the static pressure head in the air duct at this end is highest. In an alternative arrangement shown in Figure 11, a number, three as shown, of partition members 54 in the air duct defining subsidiary passageways lead air to a number of aligned air outlets 55. In this alternative there is no outlet directed towards the container storage at top 34. The generally circular filter 40 as shown in cross- section in Figure 12 comprises a pad 56 of activated carbon in a foam structure for absorbing mercury vapour, or other fumes or toxic vapours, sandwiched between on either side an inner scrim layer 57 and an outer open dust filter 58 of non-woven fabric. The sandwich structure is retained together by a pair of formed styrene rings 59, 60 which are clipped or glued together. Each ring has an inwardly directed flange 61, 62 between which the edge of the sand-
- UlE4 OMPI wich is located. The outer ring 59 has a rim 63 having three cut outs allowing passage of the heads of the screws 41 on fitting of the filter. It is secured by twisting to bring the heads over the rim. When secured the inner ring 5 61 bears against the end wall 13 with a small rim 64 en¬ gaging in the aperture 42.
In normal operation of the cabinet with lid closed, the air therein is filtered by means of repeated passes through the filter 40. The efficiency of the filter 40 is not 0 100%, however by the time the air in the cabinet has passed repeatedly through the filter, the level of fumes and toxic vapours in the atmosphere of the cabinet interior is sub¬ stantially reduced to zero or immeasurably small concen¬ tration levels. 5 In the arrangement of the preferred embodiment, at its low speed of operation the motor and impeller is capable of passing the entire air volume of the cabinet interior through the filter 40 three times per minute. An extremely severe test of the cabinet was carried out by placing 500 mg. (a o massive amount compared to day-to-day spillages or droplets) of liquid mercury in an open dish placed on the base 30. The internal temperature of the cabinet was 23°C whilst vapourisation of the mercury proceeded. The resulting level of mercury vapour contamination vastly exceeded the 5 maximum reading 2.00 mg.Hg/cubic meter of the available mercury vapour detector. With the door 12 closed, the measured level of mercury vapour contamination was reduced as follows:-
Elapsed Time Measured Level 0 20 minutes 0.05 mg.Hg/cubic metre
27 minutes 0.04 mg.Hg/cubic metre
75 minutes 0.00 mg.Hg/cubic metre
Such performance levels are sustainable in practice with regular replacement of the filter at monthly intervals. When the door is opened, the air curtain indicated by the arrows 65 in Figures 1 and 5, is intensified. If an operator releases mercury vapour, either by spillage or mere pouring of mercury, the high speed of filtration quickly absorbs the vapour. Further, the high speed air curtain tends to disperse quickly any vapour which does escape possibly where the operator's hands pass through the air curtain.
Thus it may be seen that the cabinet provides a safe environment for working with toxic vapour producing sub- stances such as mercury. Spillages in the cabinet are contained. The vapour is filtered. Possibly contaminated instruments and the like can be stored.
The invention is not intended to be restricted to the details of the above described embodiment.
-WZE
_.. OMPI

Claims

We claim:
1) A storage cabinet for fume and/or toxic vapour pro¬ ducing meterials, the cabinet comprising a body (11) of the
5 cabinet; an aperture (53) in the cabinet body (11) for access to the interior of the cabinet; a door (12) movably mounted on the body (11) of the cabinet for closing the access aperture (53) ; characterised in that the cabinet further comprises means (31,39,44) for circulating air ° within the cabinet and a toxic vapour absorbing filter (40) through which air within the cabinet is circulated for absorption of the toxic vapour.
2) A storage cabinet as claimed in claim 1 wherein elas- tomeric sealing elements (20,21,22,26) are provided on the door (12) or the body (11) of the cabinet whereby the door is sealed to the body of the cabinet when closed.
3) A storage cabinet as claimed in claim 2 wherein the door (12) is curved and is pivoted to the body of the ca¬ binet about a point (15) eccentric from the centre (18) of the curve whereby in closing of the door the sealing ele¬ ments are closed onto.
4) A storage cabinet as claimed in claim 1 wherein the air circulating means (31,39,44) is arranged to induce a swir¬ ling action of the air in the cabinet.
5) A storage cabinet as claimed in claim 4 wherein the air circulating means (31,39,44) includes an elongate exit slot
(37), or a series of short aligned exit apertures (55), for directing filtered air across the aperture (53) .
6) A storage cabinet as claimed in claim 4 wherein the elongate slot (37) is narrower at the end thereof remote fro the filter (40) .
7) A storage cabinet as claimed in claim 5 wherein each short apperture (55) is at the exit from a subsidiary pas- sageway, air being circulated through the passageways in parallel.
8) A storage cabinet as claimed in claim 1 wherein the air circulating means (31,39,44) comprises a pump (39,44) having an impeller (39) mounted within the body (11) of. the cabinet and a motor (44) mounted outside the body (11) of the cabinet.
9) A storage cabinet as claimed in claim 8 wherein the motor (44) and the impeller (39) are mounted as a replace¬ able unit on a removable portion (46) of a wall of the body (11) of the cabinet.
10) A storage cabinet as claimed in claim 1 wherein the filter (40) is mounted as a replaceable unit at an inlet
(42) to the air circulating means (31,39,44).
11) A storage cabinet as claimed in claim 10 wherein the filter (40) comprises a pad (56) of activated carbon sand- wiched between porous non-woven fabric layers (57,58) and retained in a ring (59,60) of plastics material having a pair of inwardly directed flanges (61,62) engaging the non- woven fabric layers (57,58) on the respective exterior faces thereof.
12) A storage cabinet as claimed in claim 11 wherein the ring (59,60) of plastics material comprises a pair of sty¬ rene mouldings (59,60) glued or clipped together.
13) A storage cabinet as claimed in claim 1 wherein the
O PI xΛr- , VΛPO -11-
cabinet is rectangular with the access aperture (53) ex¬ tending at the front side (28) thereof and has a base (30) and the air circulating means (31,39,44) comprises an air duct (31) having one portion extending in the corner between the base (30) and one end wall (13) of the cabinet body and another portion in the corner between the base (30) and the front side (28) of the cabinet body with an air inlet (42) being provided at the rear end of the end wall portion of the duct and an air outlet (37) being provided along the rear upper edge of the front portion of the duct, the upper surface (34) of the end wall portion of the duct providing a container storage space, the upper surface (35) of the front portion of the duct providing a container storage space, the upper surface (35) of the front portion of the duct pro- viding an instrument storage area and the remaining free area of the base (30) providing an apparatus storage area.
14) A storage cabinet as claimed in claim 13 wherein an electric power socket (38) is provided in a surface raised above the upper surface (34) of the end wall portion of the duct above the air inlet (42) .
15) A storage cabinet as claimed in claim 1 wherein the air circulating means (31,39,44) includes a pump (39,44) having a motor (44) switchable between a high speed and a low speed according to whether the door (12) is open or closed and a switch (49) actuated by the door (12) for switching the motor between its two speeds.
16) A storage cabinet as claimed in claim 15 wherein the pump (39,44) includes an electronic speed control unit (48) for controlling the speed of the motor in accordance with the switching position of the switch (49) .
OMPI
EP19830903772 1982-12-06 1983-12-05 Dental fume cupboard Withdrawn EP0157774A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU713582 1982-12-06
AU7135/82 1982-12-06

Publications (1)

Publication Number Publication Date
EP0157774A1 true EP0157774A1 (en) 1985-10-16

Family

ID=3697743

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830903772 Withdrawn EP0157774A1 (en) 1982-12-06 1983-12-05 Dental fume cupboard

Country Status (3)

Country Link
EP (1) EP0157774A1 (en)
JP (1) JPS60500164A (en)
WO (1) WO1984002293A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19549396A1 (en) * 1995-05-10 1997-01-09 Doerfert Hans Joachim Safety workbench
GB0117919D0 (en) * 2001-07-23 2001-09-12 Thermo Shandon Ltd Processor device with fume extraction
KR102665564B1 (en) * 2023-02-21 2024-05-14 대구보건대학교산학협력단 Integrated alignment storage device for dental endodontic treatment

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3260189A (en) * 1963-10-29 1966-07-12 Donald D Jensen Ventilation system
DE7025282U (en) * 1969-07-08 1971-01-21 Becton Dickinson Co DEVICE FOR AIR PURIFICATION
US3728866A (en) * 1971-07-08 1973-04-24 Interlab Inc Exhaustless clean room work stations
NL7215945A (en) * 1972-11-24 1974-05-28
CA1073009A (en) * 1977-03-18 1980-03-04 Weatherford Oil Tool Co. Dental amalgamation apparatus
GB1593597A (en) * 1978-05-23 1981-07-22 Howarth Air Eng Ltd Work cabinet
GB2112927B (en) * 1981-10-29 1985-03-20 Howorth Air Eng Ltd Air conditioned safety cabinet

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8402293A1 *

Also Published As

Publication number Publication date
WO1984002293A1 (en) 1984-06-21
JPS60500164A (en) 1985-02-07

Similar Documents

Publication Publication Date Title
US4059903A (en) Controlled environment work enclosure
US5316733A (en) Clean box with sliding arms
US4108509A (en) Controlled environment work enclosure
US4098174A (en) Total exhaust laminar flow biological fume hood safety cabinet and method
US4100847A (en) Convertible, laminar flow biological safety cabinet apparatus
US4202676A (en) Safety enclosure
US4092952A (en) Automatic slide stainer
CN1867488A (en) Device possessing detachable and cleanable liquid recovery disc for forming vacuum in container
EP0044125A2 (en) Air purifying device
US3926597A (en) Cabinet for biohazardous materials
US3808750A (en) Dental model trimmer
EP0157774A1 (en) Dental fume cupboard
US2631912A (en) Serving tray cover
US20050102975A1 (en) Method and apparatus for vacuum sealing
JP2001141273A (en) Clean bench
US20020178536A1 (en) Appliance for the vacuum cleaning of dusty material and similar
US3619851A (en) Convertible canister vacuum cleaner
US20070173193A1 (en) Dangerous Mail Handler
AU687918B2 (en) Toxic work enclosure
US4213755A (en) Mercury vapor purifier enclosure
KR200387768Y1 (en) Reagent storage airtight and ventilation havefunction purify
CN211013569U (en) Clinical pathological diagnosis sampling section device
CN217173762U (en) Tumor cell culture device for anti-tumor experiments
CN219964918U (en) Self-cleaning steel storage cabinet
CN212915748U (en) A superclean bench for microbiological assay

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19841222

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB LI LU NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19860703