GB2175966A - Seal - Google Patents

Abstract

A circular lid (10) of a macerator (16) is provided with a central water spray (32) and a peripheral, rubber sealing member (38) which is secured to the lid. An inflatable, annular rubber tube (46) is positioned in an annular gap defined between the inner face of the sealing member and an annular flange (26) on the undersurface of the lid (10). The water spray (32) is supplied with water via a supply pipe (12), which communicates with the tube (46) by means of a tube (70) and a connecting elbow (64). In use, the lid is closed and the macerator is switched on thereby feeding water through the pipe (12) to inflate the tube (46), and deform the sealing member (38) into sealing contact with the aperture (18) of the macerator. When the tube (46) is fully inflated, and the lid is sealed the pressure of water is sufficient to spray water from the water spray (32). Because the seal is always operative when the water spray (32) is in use, the invention provides a seal which is effective whenever the macerator is in use. <IMAGE>

Description

SPECIFICATION Seal The invention relates to a seal for a lid, door or like closure member of a device, and in particular, but not exclusively, to such a seal for the lid of a macerato r.

A macerator is a device which breaks down materials or substances for disposal or further treatment. It is sometimes used to break down disposable paper or fibrous articles, such as bedpans, urine bottles and the like. Water is sprayed onto the articles, often through a spray in the lid of the macerator, and the articles are then mechanically pulped by one or more impellers comprising a plurality of rapidly-rotating vanes or fins. After maceration the pulp particles are sufficiently small to be discharged into a normal drainage system without fear of blocking the system.

The vanes or fins of the macerator impeller(s) are usually rotatable about a vertical axis, and a lid in the top of the macerator allows access to the macerating chamber. As will be appreciated, it is important to have a good seal between the lid and the top of the macerator, since a poor seal can lead to escape of waste material, with associated health or hygiene hazards. In particular, since the vanes or fins are rotating at high speed and there is a lot of liquid present, a large amount of small, air-borne particles are produced in an "aerosol" effect. Since these particles are small and can travel considerable distances in the air, a good seal is essential.

Known lid seals comprise a rubber ring attached to the lid or the macerator which is deformed on closing and securing the lid. These have the disadvantage that if small particles, e.g. paper pulp, are lodged between the rubber ring and the macerator, the seal may be broken. The lid may be held down by a clamp whose engagement allows operation of the macerator by a cut-out device, or may be held down by electromagnets which are energised when the macerator is switched on. The clamp requires manual engagement in order to secure the lid and the electromagnets require close contact between the lid and the maceratorto produce the required electromagnetic attraction, which might be reduced if the lid were to be held slightly apart from the macerator, e.g. by paper pulp.

It is an object of the present invention to provide a lid seal, particularly for a macerator, which mitigates or overcomes the aforementioned disadvantages, yet which provides a good seal between the lid and the macerator.

In accordance with the present invention, a seal for releasably sealing a lid, door or like closure member in an aperture of a device, comprises an inflatable member attached to either the said closure member or device, and which is inflatable with fluid when the member is in closed condition on the device, thereby to urge the seal into sealing contact with the other of said closure member and device.

Preferably the seal comprises the inflatable member and a resiliently deformable sealing member, inflation of the inflatable member urging the resiliently deformable sealing member into sealing contact.

Preferably the inflatable member and the resiliently deformable member are at least partially annular, and concentric. Preferably the inflatable member is annular and, when inflated, urges an annular portion of the resiliently deformable member into sealing contact.

In a preferred embodiment, a lid comprises a substantially rigid base portion, a sealing member attached to said base portion and having a resiliently deformable sealing portion, the inflatable member being positioned between the sealing portion and part of the base portion.

The lid may have a water spray which is housed in the lid, and preferably the water supply to the spray also supplies water to the inflatable member.

Preferably, operation of the spray by application of water pressure causes the inflatable member to inflate with water to produce the seal as a result of hydraulic pressure.

The lid may be the lid of a macerator.

By way of example only, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, which is a crosssectional side elevation of an embodiment of macerator lid according to the invention.

A generally circular macerator lid 10 is pivotally connected by means of a water supply pipe 12 to a pivot 14, and is pivotable from a first position, shown in dotted lines, in which it is inclined to the upper surface of a macerator 16, to a second position, shown in full lines, in which the lid is positioned in a circular aperture 18, having downwardly-tapering walls.

The macerator lid 10 comprises a main body portion 20 of glass-reinforced plastics, comprising a disc 22 having inner and outer circular ribs 24,26 respectively, concentric with the disc 22 and projecting from its undersurface. A circular hole 28, partially defined by the inner wall of rib 24, passes through the disc 22 and a housing 30 of a lid spray 32 is fixed therein, as will be explained later.

A lid assembly 34, attached to the main body portion 20, comprises a thin circular rubber diaphragm portion 36 which is integrally moulded with a sealing portion 38 extending around the circumference of the diaphragm portion 36. The sealing portion has a downwardly-tapering outer wall 40 which is shaped to mate with the aperture 18 of the maceratorleaving a gap of about 1.6 mm (about 1/16 inch), and an inner wall 42 substantially perpendicular to the diaphragm portion 36. An annular gap 44 is left between the inner wall 42 of the sealing portion 38 and the outer wall of the outer circular rib 26, and houses an inflatable annular rubbertube 46, in the form of a conventional bicycle tube with the core of its Such raider valve 72 removed, as will be explained later.A metal support disc 48 is moulded into the lid seal assembly adjacent to the diaphragm portion 36 and an annular mounting ring 50 is moulded into the outer wall 40 of the sealing portion 38.

As mentioned previously, the housing 30 of a lid spray 32 projects through the hole 28. The housing 32 abuts the upper surface of the body portion 20 by means of a shoulder 52. The diaphragm portion 36, the metal support disc 48 and a retaining plate 33 are provided with aligned holes in their centre through which the lid spray 32, of conventional construction, is passed, and then screwed into the lid spray housing 30. A rubber washer 35 is positioned in between the lid spray 32 and the retaining plate 33. In this way the lid seal assembly 34 is secured to the main body portion 20, with the support disc 48 abutting the ribs 24, 26 and with the upper surface 54 of the sealing portion abutting the undersurface of the circular disc 22 of the main body portion 20.The lid seal assembly 34 is further secured to the main body portion 20 by a plurality of countersunk bolts 56 passing through holes in the mounting ring 50 into tapped sockets in the main body portion 20.

A water supply pipe 12 is connected to the housing 30 of the lid spray 32 and supplies water to the lid spray 32 in a conventional manner viva a bore 60 when the macerator is in use. A pipe 62 leads from the water supply pipe 12 and is connected to an elbow joint 64 situated through an aperture 66 in the circular disc 22 and in the annular gap 68 defined by the ribs 24, 26, the undersurface ofthe disc portion 22 and the support disc 48. The elbow joint 64 is connected via a further pipe 70 to the valve inlet 72 of the bicycle inner tube 46, from which the core ofthe valve has been removed, as previously explained.

As can be seen from the Figure, the water supply pipe 12 connects the lid to the pivot 14 which is concentric with a fixed mains water supply 74. Two counterbalance springs 76 are attached to a lug 78 which pivots with the lid, and to the macerator 16.

These are positioned such that when pivoted to an angle of 45 , the lid stays open, and that when the lid is nearly shut, the springs help to shutthe lid.

The macerator itself is of generally conventional construction, apart fro the lid. It comprises a plurality of rotating vanes or fins (not shown) in its interior which are operated electrically by pushing a switch and which perform th pulping operation.

Operation of the switch also causes the flow of water to the lid spray to commence.

Operation of the macerator is as follows. The macerator lid 10 is pivoted open and the articles to be disposed of, e.g. disposable urine bottles or bedpans, are placed into the macerator via the aperture 18. A safety cut-out switch (not shown) operated by the lid ensuresthatthe macerator can not be operated when the lid is open.

When the articles have been placed into the maceratorthe lid is pivoted downwardly into the position shown in full lines in the Figure. The switch which operates the macerator is then operated, which rotates the vanes or fins and supplies water to the water supply pipe 12 at a pressure of about 210 kPa (about 30 p.s.i.). As well as flowing towards the lid spray 32, the water flows into the inflatable rubber inner tube via the pipes 62,70, the elbow joint 64 and the modified Schraeder valve 72. The rubber inner tube is thus filled with water. The inner tube fills the annular gap 44 and presses on the annular rib 26 and the inner wall 42 of the sealing portion 38.The annular rib 26 is relatively rigid and is not substantially deformed, but the sealing portion 38 is made from rubber and the pressure on its inner wall 42 causes the sealing portion 38, and in particular the downwardly-tapering outer wall 40, to bulge outwards. Since the outer wall 40 and the face of the aperture 18 are separated-only by about 1.6 mm (about 1/16 inch) the bulging of the sealing portion 38 causes the outer wall 40 to be forced into sealing contact with the material forming the aperture, around the whole ofthe lid seal. Once the inner tube 46 is fully inflated with water, which takes about a second, the waterflows uninterrupted through the water supply pipe and to the lid spray in the conventional manner.

Thus, whenever the maceratoris being operated, i.e. whenever water is flowing through the lid spray, a tight seal is automatically made between the aperture and the lid, and the risk of waste material escaping from the macerator is considerably reduced. Moreover, if small particles, e.g. pieces of paper pulp from the disposable articles, are trapped between the sealing portion and the tapering walls of the aperture, the resiliency of the sealing portion allows the sealing portion to form itself around the particles, and the seal is thus maintained around the whole of the perimeter of the aperture.

The invention is not restricted to the details of the foregoing embodiment. For example, the invention need not be used with a macerator. It may be used wherever a releasablefluid-tightseal is required, e.g. on the door of a washing machine.

Claims (12)

1. A seal for releasably sealing a lid, door or like closure member in an aperture of a device, comprising an inflatable member attached to either the said closure member or device, and which is inflatable with fluid when the member is in closed condition on the device, thereby to urge the seal into sealing contact with the other of said closure member and device.

2. A seal as claimed in claim 1, comprising the inflatable member and a resiliently deformable sealing member, inflation ofthe inflatable member urging the resiliently deformable sealing member into sealing contact.

3. A seal as claimed in claim 2,wherein the inflatable member and the resiliently deformable member are at least partially annular.

4. A seal as claimed in claim 3, wherein the inflatable member and the resiliently deformable member are concentric.

5. A seal as claimed in claim 3 or claim 4, wherein the inflatable member is annular and, when inflated, urges an annular portion of the resiliently deformable member into sealing contact.

6. A seal as claimed in any of claims 1 to 5,wherein a water supply to the device also supplies water to the inflatable member.

7. A seal as claimed in claim6, wherein operation of the device by application of water pressure causes the inflatable member to inflate with water to produce the seal as a result of hydraulic pressure.

8. A lid comprising a substantially rigid base portion, a seal as claimed in any of the preceding claims, said seal comprising a sealing member attached to said base portion and having a resiliently deformable sealing portion, the inflatable member being positioned between the sealing portion and part of the base portion.

9. A lid as claimed in claim 8, comprising a water spray which is housed in the lid.

10. A lid as claimed in claim 8 or claim 9, wherein the lid is the lid of a macerator.

11. A seal substantially as herein described, with reference to, and as illustrated in, the accompanying drawing.

12. A lid substantially as herein described, with reference to, and asillustrated in, the accompanying drawing.