GB2304616A

GB2304616A - Transfer port

Info

Publication number: GB2304616A
Application number: GB9616666A
Authority: GB
Inventors: Andrew Bryan Birchall
Original assignee: AEA Technology PLC
Current assignee: Ricardo AEA Ltd
Priority date: 1995-08-24
Filing date: 1996-08-08
Publication date: 1997-03-26
Anticipated expiration: 2016-08-08
Also published as: GB2304616B; GB9616666D0; GB9517302D0

Abstract

A double-lid type of transfer port (10) to enable a drum (12) to communicate with a containment such as a glove-box (22) includes a frame (16) and a door (18). The frame (16) locates the lidded end of the drum (12) and includes a seal (26) to seal to its outer curved surface. The door (18) seals to the lid (14) around its periphery (32), and can be clamped to it for example by a suction clamp (36). The port (10) does not require special-purpose drums.

Description

Transfer Port This invention relates to a transfer port whereby a first container may be sealed to a port of a second container and material transferred between the two containers.

Such transfer ports may be called "double lid" systems, as the lid of the first container must be sealed and clamped to the door (or lid) of the port whenever the port is open. They are used where hazardous or nuisance materials are being handled, for example to enable a material to be transferred between a drum and a glove box; the material might be radioactive, poisonous, inconvenient to handle, or might include pathogenic micro-organisms.

Such systems are described for example in UK patents GB 1 270 069, GB 1 397 587 and GB 2 218 663 B. However these require specially designed drums and lids, which are more expensive than conventional general-purpose drums.

According to the present invention there is provided a transfer port whereby a first container, comprising a drum with a lid, may be arranged to communicate with a second container, the transfer port comprising a frame defining an aperture communicating with the second container, a door for the aperture, and a seal between the door and the frame, wherein the frame defines a short duct extending away from the location of the closed door to locate the lidded end of the drum, the duct being provided with a seal for sealing to the curved outside surface of the drum, and wherein the door includes a peripheral seal for sealing to the lid of the drum and means to clamp the lid onto the door.

Preferably the seal associated with the duct is an annular, inflatable seal. The seal on the door for sealing to the lid of the drum may be integral with the seal between the door and the frame. The clamping means might be electromagnetic, if the lid is of ferromagnetic material such as mild steel, but is preferably a suction clamp as this can clamp to lids of any material.

Such a transfer port can be used with standard drums. Clearly the drums must be of the correct diameter to locate in the duct, but special-purpose grooves and flanges etc. are not necessary. The lid of a drum is typically secured to the drum by clips or by a circumferential clamping strip, which must be removed (using conventional techniques) before the drum is located in the duct. This gives no problems where the transfer port is in the floor of the second container, but particularly if the transfer port is in a vertical wall it is desirable to ensure the lid does not fall off the drum during and after removal of the securing means.

Therefore the door preferably also includes means to urge the lid away from the door (and so onto the drum) when the drum is close to the door. This is preferably a resilient means, for example it might comprise one or more springs; or it might comprise hydraulic or pneumatic means, for example an air-filled bladder. Such a bladder might be integral with a suction clamp.

Desirably the transfer port is combined with a cradle to support and locate the drum adjacent to it, and means to move a drum along the cradle into engagement with the transfer port. The drum moving means might comprise a screw mechanism, or a hydraulic or pneumatic jack mechanism.

The invention will now be further described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 shows a sectional view through a transfer port; Figure 2 shows a sectional view through an alternative transfer port; and Figure 3 shows a view on the arrow P of Figure 2 showing part of the transfer port.

Referring now to Figure 1, this shows a sectional view through a transfer port 10, along with a drum 12 and lid 14. The drum 12 and the lid 14 are shown in chain dotted lines, and are shown in different positions relative to the port 10 above and below the centre line A-A.

The transfer port 10 comprises an annular frame 16 and a circular door 18. The frame 16 locates in a corresponding circular aperture in a rigid wall 20 of a glove box 22 and is sealed and secured to the wall 20.

The frame 16 defines a flange 23 which abuts the outside of the wall 20 and a short tube 24 which projects outside the wall and is of large enough internal diameter to locate the lidded end of the drum 12. The bore of the tube 24 tapers, being larger nearer the door 18, and at the end of the tube 24 remote from the door 18 is an internal groove in which is an inflatable annular seal 26.

The door 18 is connected to the wall 20 by a hinge 28 and is provided with means (not shown) whereby it may be secured in the closed position. It is dish-shaped in cross-section, with a flat flange 30 and a flat central plate 31 set back from it; the flange 30 abuts the wall 20 around the frame 16 and to it is fixed an annular rubber seal 32. The seal 32 has a tapering outer surface which mates and seals with the bore of the tube 24 when the door 18 is closed, and has a stepped bore 33 to seal to the periphery of the lid 14. Attached to the centre of the door 18 by a mounting bracket 35 is a suction clamp 36, and a flexible pipe 38 extends from the clamp 36 passing into the glove box 22 via a hole at the centre of the plate 31 sealed by a grommet.Four spring-loaded telescopic arms 44 are also attached to the door 18, and in their unstressed state project beyond the open end of the frame 16 (see the upper part of Figure 1).

In operation, the drum 12 with its lid 14 secured by a toggle-operated clamping strip 46 is supported on a cradle (not shown) and pushed towards the transfer port 10, for example by a hydraulic jack (not shown). When the drum 12 reaches the position shown in the upper part of Figure 1 the telescopic arms 44 are exerting sufficient force on the lid 14 that the clamping strip 46 can be safely removed (by means of the toggle) with the lid 14 held securely onto the drum 12.

The drum 12 is again pushed towards the port 10, compressing the telescopic arms 44 further, until the lid 14 seals onto the seal 32. The operation of the jack then stops, and the annular seal 26 is inflated via a duct 48 so as to seal the outside of the drum 12 to the port 10. The lid 14 is then secured to the door 18 by the suction clamp 36, by extracting air through the pipe 38. This situation is shown in the lower part of Figure 1.

The door 18 with the lid 14 secured and sealed to it can then be opened, and materials transferred between the drum 12 and the glove box 22. The door 18 can then be closed again, the suction clamp 36 released, the annular seal 26 deflated, the drum 12 withdrawn to the position shown in the upper part of the drawing, and the clamping strip 46 secured again.

It will be observed that the drum 12 shown has a peripheral groove just below the lid 14, and that in operation of the transfer port 10 the seal 26 was inflated into this groove, but it will be appreciated that this is not essential to operation of the transfer port 10, and that the seal 26 would seal equally effectively to a drum without such a groove. It will also be observed that the seals 26 and 32 are such that very little of the external surfaces of the drum 12, the lid 14 or the door 18 are exposed to the possibility of contamination by the hazardous materials, so very little cleaning is required.

It will be appreciated that the transfer port may be modified in many ways while remaining within the scope of the invention. For example the tube 24 might be longer, and might be provided with two inflatable seals 26 side by side. Furthermore the inflatable seal 26 might instead be replaced by one or more flexible rubber, annular, flap-like, wiping seals. The mechanism to clamp the lid 14 to the door 18 might also differ, for example incorporating an electromagnet. And the telescopic arms 44 might be replaced by a different device for example pneumatically operated piston and cylinder assemblies (which would provide the benefit that the clamping mechanism would not be required to overcome the force of the telescopic arms), and their number might be different.A suction clamp similar to that shown might include a rubber diaphragm which could be inflated to form a bladder and so to urge the lid 14 onto the drum 12 when required, so that no separate telescopic arms 44 or equivalent devices would be required.

Referring now to Figure 2 there is shown a sectional view through an alternative transfer port 50, differing from the transfer port of Figure 1 principally in that there are no telescopic arms 44, and that the suction clamp 36 is itself mounted on a resilient telescopic support. As with Figure 1, the drum 12 and the lid 14 are shown in chain dotted lines, and are shown in different positions relative to the port 50 above and below the centre line B-B.

The transfer port 50 comprises an annular frame 52 and a circular door 54. The frame 52 locates in an aperture in a rigid wall 20 of a glove box 22 and is sealed and secured to the wall 20. The frame 52 defines a short tube 56 which projects outside the wall 20 and is of large enough bore to locate the lidded end of the drum 12. The bore of the frame 52 tapers, being larger nearer the door 54; and at the end of the tube 56 remote from the door 54 is an internal groove in which is an inflatable annular seal 58.

The door 54 is connected to the inside of the wall 20 by a hinge 28, and is provided with a clamp mechanism 60 so it can be secured in the closed position. It is flat, with a tubular flange 62 around its periphery which engages a slot in an annular seal 64. The seal 64 has a tapering outer surface to mate and seal to the tapered bore of the frame 52, when the door 54 is closed, and has a stepped bore 66 to seal to the periphery of the lid 14.

At the centre of the door 54 is a circular aperture and a support tube 68 fixed to the outside of the door 54. At an intermediate position along the length of the tube 68 is an internal support flange 70 to which is secured and sealed a flange of a short guide tube 72. A vacuum pipe 74 slides in the bore of the guide tube 72, to which it is sealed by an O-ring 75. One end of the pipe 74 is connected via a screw fitting 76 to a suction clamp 36. To the end of the pipe 74 outside the flange 70 are connected a rotatable locking ring 78 with a radially-extending handle 80; and a vacuum pipe coupling 82 to connect to a flexible pipe 84. A compression spring 85 surrounds the pipe 74 between the guide tube 72 and the screw fitting 76, and a spring-locating sleeve 86 slides on the pipe 74 at the middle of the spring 84.

The outer portion of the support tube 68 defines a slot 87 along which the coupling 82 slides, and a slot 88 along which the handle 80 slides. As shown in Figure 3, a cam slot 90 branches off from the slot 88, with an inclined surface 91 nearest the door 54, and a locating notch 92.

In operation, the drum 12 with its lid 14 secured by a clamping strip 46 is moved towards the transfer port 50. When the drum 12 reaches the position shown in the lower part of Figure 2 the spring 85 is exerting sufficient force on the lid 14 that the clamping strip 46 can be safely removed, while the lid 14 remains securely on the drum 12.

The drum 12 is then moved closer to the port 50 so the lid 14 seals to the peripheral seal 64, as shown in the upper part of Figure 2; and the annular seal 58 is inflated (as shown) to seal the outside of the drum 12 to the port 50. The lid 14 is secured to the door 54 by means of the clamp 36, by extracting air through the pipe 84. The handle 80 is then turned into the slot 90 until it engages the inclined surface 91, and then turned further until it reaches the notch 92. Moving the handle 80 along the inclined surface 91 pulls the pipe 74 further through the guide tube 72, and so compresses the spring 85 further, to ensure the lid 14 is not bowed.

Then, as with the port 10, the door 54 with the lid 14 secured and sealed te it can then be opened, and materials transferred between the drum 12 and the glove box 22. The door 54 can then be closed again, the handle 80 turned back into the slot 88, the suction clamp 36 released, the annular seal 58 deflated (as in the lower part of Figure 2), the drum 12 withdrawn to the position shown in the lower part of the Figure, and the clamping strip 46 secured again.

Claims

1. A transfer port whereby a first container, comprising a drum with a lid, may be arranged to communicate with a second container, the transfer port comprising a frame defining an aperture communicating with the second container, a door for the aperture, and a seal between the door and the frame, wherein the frame defines a short duct extending away from the location of the closed door to locate the lidded end of the drum, the duct being provided with a seal for sealing to the curved outside surface of the drum, and wherein the door includes a peripheral seal for sealing to the lid of the drum and means to clamp the lid onto the door.

2. A transfer port as claimed in Claim 1 wherein the duct is provided with an annular, inflatable seal.

3. A transfer port as claimed in Claim 1 or Claim 2 wherein the peripheral seal on the door for sealing to the lid of the drum is integral with the seal between the door and the frame.

4. A transfer port as claimed in any one of the preceding Claims wherein the clamping means comprises a suction clamp.

5. A transfer port as claimed in any one of the preceding claims also including means to urge the lid away from the door when the drum is close to the door.

6. A transfer port as claimed in Claim 5 wherein the urging means comprises at least one resilient arm.

7. A transfer port as claimed in Claim 5 wherein the urging means comprises at least one pneumatic or hydraulic device.

8. A transfer port as claimed in Claim 5 wherein the clamping means is connected to the door by support means, and the said support means exerts a resilient force to urge the lid away from the door when the drum is close to the door.

9. A transfer port as claimed in Claim 8 wherein the support means also includes means to suppress the resilient force on the lid.

10. A transfer port substantially as hereinbefore described with reference to, and as shown in, Figure 1, or Figures 2 and 3, of the accompanying drawings.