GB2198490A

GB2198490A - Sealing device

Info

Publication number: GB2198490A
Application number: GB08715556A
Authority: GB
Inventors: Keith Stephenson
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-07-02
Filing date: 1987-07-02
Publication date: 1988-06-15
Also published as: GB8715556D0; GB8616147D0

Abstract

A sealing device 10 for providing an airtight seal between a vessel (22) and its closure means (28) comprises an elongate flexible member e.g. of substantially rectangular cross-section having a V-sectioned cut-away portion in one face and an elliptical or circular cavity 12 therein along its length. The cavity 12 communicates with a fluid supply e.g. via slits (16), and the device is inflated by introducing fluid, e.g. compressed air, into the cavity. The inflated device then comes into intimate contact with the closure means of the vessel to provide an airtight seal. <IMAGE>

Description

SEALING DEVICE This invention relates to a sealing device, and particularly though not exclusively to a door seal for a steam sterilizing machine.

Steam sterilizing apparatus is nowadays essential in many establishments, particularly hospitals. It is typically used to sterilize gowns, bedding, surgical instruments and the like. A steam sterilizing device usually comprises a large chamber into which items to be sterilized are placed. The chamber has at least one opening through which articles are loaded into the chamber and this opening is usually closed by means of a sliding door. A sealing medium is located at the periphery of the opening and forms an airtight seal between the chamber and the door during a sterilizing operation.

Steam sterilizing machines in use at present have means located at the periphery of the opening to house the sealing medium. These means are typically two metallic members extending around the whole periphery of the opening, the space between the two metallic members being occupied by the sealing medium. The sealing medium typically used is an endless, solid cylindrical length of rubber (usually silicone rubber).

However, these cylindrical rubber seals are not as efficient as a sealing medium as one would expect. The metallic members at the periphery of the opening are welded along one side thereof to the chamber. This is unsatisfactory as such welds become weakened after a time causing deformation of said metallic members. This can mean that the rubber seal will not fit between the metallic members snugly and the seal will be impaired. Furthermore, the distance between the two metallic members, i.e. the width of the channel into which the rubber seal fits, can vary significantly and this can cause problems because the seal may not occupy the whole of the width of the channel.

The rubber seal does not generally have sufficient flexibility to conform to the exact shape of the channel.

A further drawback with cylindrical rubber seals is that they frequently "roll" within the channel and dirt, such as ferrous oxide from the metallic members, becomes ingrained in the rubber. The sides of the seal which contact the metallic members also become flattened which can also contribute to inaccurate fitting within the channel. The cylindrical rubber seal has a relatively short lifetime and must therefore frequently be replaced, and the cost of silicone rubber is extremely high.

It is an object of the present invention to provide a sealing medium for the door of a vessel which overcomes or reduces the above disadvantages.

According to the present invention there is provided a sealing device for use with a vessel having an opening therein which may be closed by a closure means, the sealing device comprising an elongate flexible member including a cavity therein which extends throughout its entire length or a substantial part thereof, and means allowing fluid to be introduced into the cavity to inflate the elongate flexible member so as to cause it to come into intimate contact with the closure means thereby forming an airtight seal between the vessel and its closure means.

Conveniently, the means for allowing fluid to be introduced into the cavity also allows said fluid to be withdrawn from the cavity to deflate the elongate flexible member and cause it to come out of intimate contact with the closure means.

Typically, the sealing device of the present invention would be used to provide a seal between the body of a steam sterilising machine and the door of the machine. Such machines are conventionally provided with a "channel", which is formed from two spaced apart strips of metal, around the periphery of the opening. The sealing device of the present invention is pressed into this channel to provide the sealing effect described above.

Preferably the sealing device is of substantially rectangular cross section having a cut-away portion in one face thereof.

The cut-away portion is preferably a 'V'-section, said 'V'-section facing inwardly when the sealing device is located in the channel.

The fluid may be a gas, such as compressed air or steam, or may be a liquid, e.g. water.

The cavity inside the sealing device is preferably elliptical or circular in cross section. The cavity enables the sealing device to readily conform to the shape of the channel in which it is housed.

Preferably the sealing device is prov-ided with one or more slits located at the base of the 'V'-section, the slits opening into the cavity. These slits enable gas (usually compressed air) to be introduced into and removed from the cavity thereby inflating and deflating the sealing device in sequence.

The sealing device is preferably constructed from silicone rubber.

The invention will now be described further, with reference to and as illustrated in the accompanying drawings, in which: Figure 1 is a perspective view of a section of a sealing device in accordance with the invention; Figure 2 is an end view corresponding to Figure 1; Figure 3 is a plan view showing one of a plurality of slits located at the base of the 'V'-section; and, Figure 4 shows the sealing device in position at the periphery of an opening of a steam sterilizing machine.

Referring to the drawings, a sealing device 10 is an endless piece of silicone rubber of substantially rectangular cross section having a cut-away 'V'-section in one face thereof, as can be seen from Figure 1 of the drawings. The device has a cavity 12 which is elliptical in shape and which extends throughout the entire length of the device. The cavity 12 increases the flexibility of the device and therefore allows it to be more readily located in position on a steam sterilizing machine. At the bottom of the 'V'-section there is a flat section 14 which also extends throughout the entire length of the device. A plurality (perhaps four) slits 16 are cut in the flat section 14. These slits are located at approximately equal intervals throughout the length of the sealing device.

In use of the device it is positioned between two members 18, 20 which define a channel at the periphery of an opening to a steam sterilizing machine 22. The sealing device is positioned such that the 'V'-section points rearwardly into the channel and the flat bottom surface 24 provides the sealing edge. Items which need to be sterilized are placed in the chamber 26 of the sterilizer 22 and a sliding door 28 is moved into its closed position in which it covers the opening to the chamber 26. A plurality of holes (not shown) is located in the back of the channel and these holes act as inlets for compressed air. The air then circulates through the 'V'-section of the sealing device and is introduced into the cavity 12 via slits 16. This effectively inflates the sealing device to a slight extent, and this causes the device to "blow out" from the channel and contact the inner surface of the sliding door 28. The slight inflation of the device results in a snug fitting within the channel and gives rise to an airtight seal. Furthermore, the side limbs of the V are forced apart by the compressed air to seal on members 18, 20 which further secures the device within the channel.

This is a distinct advantage since the width of the channel can vary significantly and if the sealing device does not occupy the whole of the channel, the seal will not be airtight.

The sterilizing process is then commenced. This normally involves alternate application of vacuum and steam under pressure to the interior of the machine 22. Owing to the swings of pressure within the machine, the door 28 moves inwards and outwards to some extent. On the 'vacuum' parts of the cycle the door 26 is pulled tightly onto the seal 10, but on the 'steam' parts of the cycle it is pushed outwardly. The construction of the device of the invention, in particular the provision of slots 16, causes the seal to be forced outwardly under high pressure conditions to maintain good sealing contact with the door 26, owing to the fluid pressure applied at the back of the seal device 10.

When the sterilizing operation is complete air is evacuated from the channel and the cavity of the sealing device by means of a vacuum system. This causes the device to "suck back" into the channel thereby breaking the seal with the door. The door can then be opened and the sterilized items removed from the chamber.

To remove the sealing device from the channel compressed air is pumped into the channel when the door is open which blows out the sealing device from said channel.

The present invention provides a much improved airtight seal for a vessel. It has a very long lifetime, whereas present seals need to be replaced quite frequently.

Furthermore, it is able to fit much easier into its associated channel due to its higher degree of flexibility, and conforms closely to the channel in operation even though the latter may have irregularities in width.

Claims

1. A sealing device for use with a vessel having an opening therein which may be closed by a closure means, the sealing device comprising an elongate flexible member including a cavity therein which extends throughout its entire length or a substantial part thereof, and means allowing fluid to be introduced into the cavity to inflate the elongate flexible member so as to cause it to come into intimate contact with the closure means thereby forming an airtight seal between the vessel and its closure means.

2. A sealing device according to Claim 1 in which the means for allowing fluid to be introduced into the cavity also allows said fluid to be withdrawn from the cavity to deflate the elongate flexible member and cause it to come out of intimate contact with the closure means.

3. A sealing device according to Claim 1 or Claim 2, in which the flexible member is of substantially rectangular cross section having a cut-away portion in one face thereof.

4. A sealing device according to Claim 3, in which the cut-away portion is a 'V'-section.

5. A sealing device according to any of the preceding claims in which the cavity is circular in cross-section.

6. A sealing device according to any of Claims 1 to 4 in which the cavity is elliptical in cross-section.

7. A sealing device according to any of the preceding claims in which the means for allowing fluid to be introduced into the cavity comprises at least one slit communicating with the cavity.

8. A sealing device according to any of the preceding claims in which the flexible member is made from silicone rubber.

9. A sealing device according to Claim 1 and substantially as herein described.

10. A sealing device substantially as herein described with reference to the accompanying drawings.

11. A vessel having an opening therein which may be closed by a closure means and including a sealing device in accordance with any of the preceding claims.