GB2153254A

GB2153254A - A work bench

Info

Publication number: GB2153254A
Application number: GB08401825A
Authority: GB
Inventors: Philip Hadfield
Original assignee: Afos Ltd
Current assignee: Afos Ltd
Priority date: 1984-01-24
Filing date: 1984-01-24
Publication date: 1985-08-21
Also published as: GB2153254B; GB8401825D0

Abstract

The bench comprises a foraminous surface (3) forming a work area to receive a workpiece and means (9, 7) by which air can be drawn from above the surface to pass therebelow so as to ventilate the work area. <IMAGE>

Description

SPECIFICATION A work bench The present invention relates to a work bench and more particularly to such a bench for use in dealing with workpieces from which fumes emanate, e.g. for use in dissection work in which the specimens have been "pickled", that is to say the specimens have been preserved in formaldehyde.

It is known to carry out dissection work on pickled specimens, in an extraction cabinet to which access for the dissectionist's arms is provided by an aperture in the cabinet; air being drawn through the aperture from the exterior of the cabinet at the location of the dissectionist, then over the specimen being dissected to take up formaldehyde and any other fumes arising from the specimen, and then to be vented from the cabinet in the normaf way. By this means, the specimen is ventilated to protect the dissectionist from any fumes arising from the specimen. However, in practice, the use of the extraction cabinet has disadvantages in that it restricts physical and visual access to the specimen being dissected.

It is an object of the present invention to provide a work bench by which a specimen to be dissected or other workpiece may be more efficaciously ventilated.

There is provided by the present invention a dissection bench comprising a foraminous surface associated with a work area to receive the workpiece and means by which air can be drawn from above the surface to pass therebelow so as to ventilate the work area.

The work area may be formed as a continuous surface surrounded or substantially surrounded by foraminous surface, but in a presently preferred embodiment of the present invention, the foraminous surface itself constitutes the work area; the apertures in the foraminous surface being chosen inter alia to prevent unwanted loss of material from the workpiece therethrough.

It is also preferred that the bench comprise an arrangement to provide a substantially uniform pressure drop therethrough. For this purpose, a further foraminous surface may be used to underlie that associated with the work area.

The bench of the present invention has been found to provide effective ventilation of the work area so as to prevent any fumes arising from the workpiece from reaching the operative; but it also provides good physical and visual access to the workpiece. Further, it may be located where convenient, for example, to form a peninsular or island.

The bench may comprise a plenum chamber located below the foraminous surface or surfaces; the chamber providing a connection to a fume extraction system. At least in the case where the bench is intended for use as a dissection bench, it is preferred that it comprise a sink; it is also preferred that the sink be provided with a vent which communicates with the fume extraction system, and that means be provided by which air-flow through the foraminous surface can be substantially stopped so that substantially the entirety of the suction available can be used to extract air from the sink. The means may comprise one or more dampers, which is or are preferably adjustable to permit adjustment of the relative extraction rates from the foraminous surface and the sink, for instance, following installation of the bench.

The sink is preferably fitted with taps for hot and cold water, with a trigger operated hand shower comprising a flexible hose to facilitate washing down of the sink and with a sparge pipe.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation of a bench according to the present invention, with parts omitted to avoid unnecessary drawing; Figure 2 is a plan view, with parts broken away, of the bench of Fig. 1; Figure 3 is a detail of a further damper arrangement used in the bench of Fig. 1.

Figure 4 is a scrap section showing a damper arrangement used in the bench of Fig. 1.

Referring now to the drawings, the illustrated bench comprises a foraminous surface, generally indicated at 1, comprising a perforated plate 3. Underlying the plate 3 is a further perforated plate 5; the two plates being supported on frame members of the bench. In this instance, plate 3 has circular holes of 4 mm diameter and 8 pitch whereas plate 5 has circular holes of 1 5 mm diameter and 60 pitch. The two plates surmount an air exhaust duct 9 the top of which is covered by an unperforate plate 11. The exhaust duct comprises an enlarged head, generally indicated at 13, having perforate sides 15, with the head lying in a plenum chamber 1 7 constituted by wall sections 19, base sections 21 and plate 5. The duct at its remote end 23 is adapted to be connected to an air extraction system (not shown).When suction is applied by the latter to the plenum chamber via the air exhaust duct, air is drawn through the holes in plates 3 and 5, and the perforate sides of the head of the air exhaust duct to pass to the extraction system. In the illustrated embodiment, the foraminous surface presented by plate 3 provides a work area to receive the workpiece and the ventilation of the entirety of that surface ensures that any fumes arising from the workpiece are entrained in the moving air stream being drawn through the foraminous surface. The aperture size of the holes in plate 3 is chosen to prevent unwanted loss of material from the workpiece while the number per unit area is chosen to give the required flow rate for the extraction system to be used.The provision of plate 5 has the effect of stabilising the pressure drop across the plate 3 and of maintaining a substantially uniform pressure drop over the area of the plate i.e. the two plates 3 and 5 provide a two-stage but differential throttling action on the air stream to produce, for the extraction system to be used, a requisite air-flow to achieve an adequate ventilation of the workpiece with a stability and uniformity of the pressure drop through plate 3.

The bench further comprises a sink 25 located, as viewed in Fig. 1, at the right hand end of the bench; the plate 5 providing a turned over end position 27 overhanging the sink on the side thereof adjacent the foraminous surface so that any material, whether liquid or solid, falling therefrom falls onto the floor of the sink and not onto the adjacent side 29 thereof.

The adjacent side 29 comprises air vents, in this instance, three, connecting with the air exhaust duct; each vent being formed by a set of louvres, one set of which 33, is shown in Fig. 3. Each set of louvres is provided with a damper plate 35 comprising an operating handle 37 guided in the lowermost louvre 39 to project from the adjacent side 29 of the sink. The plate is arranged to slide in the general direction of louvre 39 so that the handle can be moved in the louvre from the position shown in Fig. 3 towards the opposite end of the louvre.

In the position shown in Fig. 3, the plate 35 leaves the louvres substantially unobstructed, but, as it is moved further towards the opposite end of the louvre 39, it increasingly obstructs air-flow through the louvres until it reaches the opposite end of that louvre, in which position it substantially stops air-flow through the louvres.

The louvres connect with the air exhaust duct via a further duct 41 (see Fig. 1) passing below the plenum chamber; and at the air exhaust duct end of duct 41 is located a further damper plate 47 mounted on a shaft 49 journalled at one end in a respective side of the air exhaust duct and passing at the opposite end through the opposite side of the air exhaust duct. The shaft is extended at the opposite end thereof (see Fig. 4) and that end is journalled in a fixed wall section 51 of the bench and carries a depending handle 53 mounted at one end thereof fast on the shaft.

Intermediate its ends, the handle comprises a bore (not shown) and the wall section 51 comprises an arcuate slot (not shown) into which is passed a bolt (not shown) to extend through the bore in the handle and to receive on the end thereof a butterfly nut (not shown).

The handle can be used to turn shaft 49 to rotate damper plate 47 as indicated by arrow 31 from the position shown in Fig. 1 in which it substantially entirely obstructs air-flow from the sink but leaves the air-flow from the foraminous substantially unobstructed, to a position in which it substantially entirely obstructs the air-flow from the foraminous surface, but leaves the air-flow from the sink substantially entirely unobstructed; and the damper plate can be set in either of these positions or in any intermediate positioning by tightening the butterfly nut to fasten the handle to wall section 51 By means of the two damper plates 35 and 47, the apportionment between the sink vent and the foraminous work surface of the available suction can be adjusted to whatever is required, whether it be an initial adjustment following installation or one for a particular operation of the bench.

The sink is also equipped with a hot water tap 55, a cold water tap 57, a sparge tube control valve 59 and a location for attachment of a flexible tube with a spray head, as indicated at 61. The plenum chamber also comprises a sparge tube 63 equipped with a plurality of spray nozzles (not shown) and controlled by control valve 59.

In operation of the bench, air flow takes place on application of suction to the foraminous surface and the sink, in the direction indicated by the arrow heads 65 to provide an effective ventilation thereof. Should a large amount of fuming liquid e.g. formalin, need to be disposed of down the sink, then substantially the entire suction can be applied thereto to ensure fumes do not migrate to the ambient atmosphere.

After use, the foraminous surface and the sink may be washed down using the spray head, and the plenum chamber may be washed down using sparge tube 63.

While the bench of the illustrated embodiment is considered to be especially useful for dissection of "pickled" specimens, it will be understood that a workbench of the present invention may be equally useful in other applications such as in removing organic solvents from materials in, e.g. a paint or chemical laboratory.

Claims

1. A work bench comprising a foraminous surface associated with a work area to receive the workpiece and means by which air can be drawn from above the surface to pass therebelow so as to ventilate the work area.

2. A bench according to Claim 1, wherein the work area is formed as a continuous surface surrounded or substantially surrounded by said foraminous surface.

3. A bench according to Claim 1, wherein the foraminous surface itself constitutes the work area.

4. A bench according to any of the preceding claims, wherein the bench comprises an arrangement to provide a substantially uni form pressure drop therethrough.

5. A bench according to Claim 4, wherein said arrangement comprises a further foraminous surface to underlie that associated with the work area.

6. A bench according to any of the preceding claims, wherein the bench comprises a plenum chamber located below the foraminous surface or surfaces; the chamber providing a connection to a fume extraction system.

7. A bench according to any of the preceding claims, wherein the bench comprises a sink.

8. A bench according to Claim 7, wherein the sink is provided with a vent to communicate with a fume extraction system.

9. A bench according to any of the preceding claims, wherein means are provided by which air-flow through the foraminous surface can be substantially stopped.

10. A bench according to Claim 9, wherein the means comprises one or more dampers.

11. A bench according to Claim 10 as dependent on Claim 8, wherein the or each damper is adjustable to permit adjustment of the relative extraction rates from the foraminous surface and the sink.

1 2. A bench according to Claim 7 or any of Claims 8 to 11 as dependent thereon, wherein the sink is fitted with taps for hot and cold water and/or with a trigger operated hand shower comprising a flexible hose to facilitate washing down of the sink and/or with a sparge pipe.

1 3. A work bench substantially as described with reference to the accompanying drawings.

CLAIMS Amendments to the claims have been filed, and have the following effect: New or textually amended claims have been filed as follows: Claims 1 3 above have been re-numbered as 14 and their appendancies corrected.

1 3. A bench according to Claim 6 or any of Claims 7 to 1 2 as dependent thereon, comprising an exhaust duct formed with a head covered with an imperforate top, and perforated sides; the head being disposed to lie in said plenum chamber so that air drawn through the foraminous surface into the plenum chamber is then drawn through the perforated sides of the exhaust duct.