GB2267528A - Window of safety cabinet - Google Patents

Abstract

A safety cabinet is provided having a window capable of sliding parallel to the aperture and pivoting away from the aperture about an axis 50, transverse to the sliding direction. This enables the window to be raised to permit access to the cabinet, and to be swung away from the cabinet to facilitate cleaning. <IMAGE>

Description

SAFETY CABINET This invention relates to a safety cabinet, and in particular to a gas-tight sealable window therefor.

Safety cabinets of many kinds are commonly used in areas such as chemical and biological research. Such cabinets provide a 'clean' working environment whilst at the same time allowing relatively easy access for a user through a window aperture. The clean environment is maintained by controlling the air flow inside the cabinet; clean air is provided to the work space, and any 'unclean' air entering through the window aperture is removed. The control of the air flow also prevents any matter e.g.

organisms or chemicals passing from the work environment through the window aperture and entering the outside environment.

It is an essential feature of such cabinets that the work environment is sterilisable. This is commonly done using a sterilising gas, and so the cabinet and especially the window aperture must be gas-tight sealable.

Two types of window aperture closure are currently used in safety cabinets: the first is a window which is fastenable over the aperture during sterilisation but which, in normal use, is wholly removed from the cabinet. The second is a window which slides up and down along the front of the cabinet and can be fastened over the aperture during sterilisation. Both of these systems may be used together with tape to complete the seal around the edges of the aperture.

In the first system, since the window is removed completely from the cabinet when in use and may have been on the cabinet for sometime after sterilization, any chemicals or organisms on the interior surface of the window may be transferred to the environment outside the cabinet. In the second system some parts of the sliding mechanism are not sterilisable in the normal way, and must be cleaned, if at all, by complete removal of the window.

Thus this system is prone to contamination and is not easily completely sterilisable. Organisms remaining after sterilisation may be transferred to the external atmosphere by use of the sliding window.

The present invention provides a safety cabinet having a gas-tight sealable window on a face thereof, the window being moveable in a sliding track linearly along the face and pivotally about a pivot axis which is transverse to the direction of linear movement. This permits the window to be slid away from the aperture when the cabinet is in use, in the conventional manner, and to be swung outwardly from the aperture to allow complete and thorough cleaning of the inside face of the window, and of the area of the cabinet surrounding the aperture.

When the window is in position over the window aperture it may be fixed in place using a number of fasteners. These fasteners may have a camming action which pulls the window tight across the aperture. The window cooperates with a sealing member on the cabinet around the aperture to provide a gas-tight seal of the cabinet. Thus the cabinet and window are easily sterilisable, and the window may be brought into place and the aperture sealed quickly and easily when required.

Two sliding tracks are preferably provided, one on each side of the aperture, on which parts of the window are adapted to slide.

According to a second aspect of the present invention the linear motion of the window is preferably controlled by the use of a gas spring and pulley apparatus. Both sides of the window are connected via cables to the moveable end of a gas spring; the other end of the gas spring is fixed. If the opening force on the window is applied unevenly i.e. at one of the edges, the set-up of the gas spring apparatus ensures that the window moves smoothly and that it is not skewed by the uneven application of the force. Since the window may be made of heavy armoured glass if it slid down uncontrolled it could cause damage. If one of the cables were to break the other cable is preferably capable of supporting the weight of the window, and thus the possibility of such an uncontrolled slide is reduced.

The pivotal motion of the window is preferably controlled by the use of two gas springs. One end of each gas spring is fixed to one of the side edges of the window, and the other end is attached to a part adapted to slide in the sliding track. Thus the window may be slid linearly when it is already swung open. As an additional safety feature, latches may be provided with which the window may be locked into position when it is fully swung open. This is a precaution against any failure of the gas springs controlling the pivotal motion.

This invention also relates to a method for sterilising safety cabinets having a gas-tight sealable window which is moveable both linearly along the face of the cabinet and radially around the pivot axis which is transverse to the direction of linear movement, comprising the steps of opening the window around its pivot axis and manually cleaning some parts, and closing the window and sterilising the interior of the cabinet. The steps may be performed in reverse order.

An embodiment of the present invention will now be described in relation to the following drawings in which: Fig 1 is a schematic diagram of an embodiment of safety cabinet; Fig 2 is a front view of the embodiment, with the window covering the aperture; Fig 3 is a front view of the embodiment, with the window raised; Fig 4 is a schematic side view of the embodiment, with the window covering the aperture; Fig 5 is a schematic side view of the embodiment, with the window raised; and Fig 6 shows a schematic view of a gas spring and pulley apparatus embodying the present invention.

Fig 1 shows a safety cabinet 2 having an internal air flow and purity control system 4,6 and a frontal aperture 8 through which a user may gain access to the work space 10. The frontal aperture 8 is coverable by a window 12 which, in this figure, is shown having been slid linearly upwards above the aperture 8. Clean air flows down through the work space 10 to the base area 16 of the cabinet and then upwards through the back area 14 to the top of the cabinet where it is returned and purified through the controller 4. Some air may be extracted through the controller 6 and passed to the outside environment. Any 'unclean' air entering the cabinet through the aperture 8 is drawn down into the base area 16 away from the work space.Thus a clean working environment is maintained, and the possibility of the escape of chemicals or organisms may escape from the work space to the outside environment is reduced.

Fig 2 shows a safety cabinet 2 in which the aperture 8 is covered by a moveable window 18. The window 18 comprises a frame 20 which surrounds a pane of armoured glass 22. The window is slidable linearly up and down parallel to the front face of the cabinet on tracks 48, and also may swing out of the plane of Fig 2 along a pivot axis parallel to the upper edge 28 of the window.

The linear sliding motion is controlled by a gas spring 30, an end 32 of the piston of which is attached to the upper end of side edges 24,26 of the window via cables 34,36. An end 38 of the cylinder of the gas spring is fixed to the cabinet. The cable 34 runs from the side edge 24 around a pulley 40 and is fixed to the end 32 of the piston of the gas spring. The second cable 36 passes from the side edge 26 around a second pulley 42 around the first pulley 40 and is also fixed to the same end 32.

Thus as the window travels linearly upwards the gas spring expands and both the cables are kept taut. If the force applied to move the window linearly upwards is applied unevenly i.e. along one edge 24 of the window, then the apparatus will ensure that both cables 34,36 are moved at the same rate, and thus possibly skewing of the window is reduced.

When the window is in a closed position i.e.

covering the aperture 8, it may be fixed in place using fasteners 44,46 situated at the bottom edge of the window.

These fasteners have a camming action and so pull the window into contact with the sealing parts of the cabinet surrounding the aperture 8, thus providing a gas-tight seal.

Fig 3 shows the safety cabinet with the window partially raised to allow the user access through aperture 8 to the work space inside the cabinet. Since the window 18 has been raised, the gas spring 30 has expanded and the cables 34,36 have been kept taut. An end of each of the cables 34,36 is fixed to the end 32 of the piston of the gas spring 30, and the characteristics of the apparatus are such that, should one of the cables 34,36 break then the other cable would hold the window in place.

In Fig 4 the track 48 mounted on the cabinet, along which the ends of the upper edge 28 of the window may slide, can be more clearly seen. The upper edge 28 of the window is connected to the rest of the window frame 20 via a hinge 50. This enables the window 18 to be pivoted outwardly from the cabinet (to the right in Fig 4), around a pivot access parallel to the top edge 28 of the window.

This pivotal motion is controlled by two further gas springs 52,54 (only the left hand spring 52 can be seen in Fig 4); one end of the spring 52 is connected to the cabinet and is also slidable in the track 48, whilst the other end of the spring 52 is connected to a-stopper 56 mounted on the window frame 20. As an additional safety feature, when the window 18 is pivoted out and fully extended as seen in dotted lines in Figure 4 it may be fastened to a hood on the cabinet (not shown).

Fig 5 shows a view similar to that of Fig 4, but from the right-hand end of the cabinet and with the window slid partially open. Since the only two parts of the window assembly which are fixed to the cabinet, ie. the upper edge 28 and the end 58 of the side gas springs 52,54, are both slidable in the track 48, then the window may be pivoted outwardly from the cabinet independently of its vertical position, and vice versa. Indeed, the window cannot be slid up and down whilst it is entirely flush with the front face of the cabinet, since in that position there would be too much friction with the face of the cabinet and with the sealing parts around the aperture.

To counter this, the equilibrium position of the window and side spring 52,54 apparatus is one in which the plane of the window is about 5O from the face of the cabinet.

Thus, when the window is released from its sealed position, it automatically swings open slightly to facilitate upward motion.

Fig 6 shows in more detail the cable and gas spring apparatus for control of the vertical motion of the window seen also in Figure 2. Cable 34 attaches via a loop 62 to the side 24 of the upper edge 28 of the window, passes around pulley 40 and is fixed to the travelling end 32 of the gas spring 30. Cable 36 is similarly fixed via a second loop 64 to the end 26 of the window 18, passes around pulley 42 and pulley 40 and is again fixed to the travelling end 32 of the gas spring 30.

Claims (6)

CLAIMS:

1. A safety cabinet having a window on a face thereof, the window being sealable to close an aperture in the cabinet in a gas tight manner and being moveable linearly in a track parallel to the face and pivotally about a pivot axis transverse to the direction of linear movement.

2. A safety cabinet according to claim 1 wherein two tracks are provided, one on each side of the aperture, on which parts of the window are adapted to slide.

3. A safety cabinet according to claim 1 or claim 2 wherein the linear motion of the window is regulated by a gas spring linked to the window by at least one flexible link.

4. A safety cabinet according to claim 3 wherein both sides of the window are connected via a said flexible link to a moveable end of the gas spring, the other end of the gas spring being fixed.

5. A safety cabinet according to claim 3 or claim 4 wherein the or each connection is capable of supporting the weight of the window independently of the other.

6. A safety cabinet according to any preceding claim

6. A safety cabinet according to any preceding claim wherein the pivotal motion of the window is regulated by at least one second gas spring.

7. A safety cabinet according to claim 6 wherein two said second gas springs regulate the pivotal motion of the window, a said second gas spring being provided at each side of the window.

8. A safety cabinet according to claim 6 or claim 7 wherein one end of the or each second gas spring is fixed to a side edge of the window, and the other end of the or each second gas spring is attached to a part adapted to slide in the track.

9. A safety cabinet according to any preceding claim wherein latches are provided for releasably retaining the window in a fully open pivoted position.

10. A safety cabinet according to any preceding claim wherein fasteners are provided to fix the window in place when it is in the closed state, and have a cam face thereby to secure the window tightly and releasably across the aperture.

11. A method for sterilising safety cabinets having a gas-tight sealable window which is moveable both linearly along the face of the cabinet and radially around a pivot axis which is transverse to the direction linear movement, comprising the step of opening the window around its pivot axis for manual cleaning, and sterilising the interior of the cabinet with the window closed.

12. A safety cabinet substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A safety cabinet having a window on a face thereof, the window being sealable to close an aperture in the cabinet in a gas tight manner and being moveable linearly in a track parallel to the face wherein the window is arranged in a way that it is releasable from its seal by pivotal movement about an axis transverse to the direction of linear movement to facilitate its linear movement.

2. A safety cabinet according to claim 1 wherein two tracks are provided, one on each side of the aperture, on which parts of the window are adapted to slide.

3. A safety cabinet according to claim 1 or claim 2 wherein the linear motion of the window is regulated by a gas spring linked to the window by at least one flexible link.

4. A safety cabinet according to claim 3 wherein both sides of the window are connected via a said flexible link to a moveable end of the gas spring, the other end of the gas spring being fixed.

5. A safety cabinet according to claim 3 or claim 4 wherein the or each connection is capable of supporting the weight of the window independently of the other.