GB2050128A

GB2050128A - Sealing arrangement for a tubular container

Info

Publication number: GB2050128A
Application number: GB7917033A
Authority: GB
Original assignee: Liquifry Co Ltd
Current assignee: Liquifry Co Ltd
Priority date: 1979-05-16
Filing date: 1979-05-16
Publication date: 1980-12-31

Abstract

A sealing arrangement e.g. for sealing cable entries into the container of a water heater or for providing a seal between the container and second container housing a thermostat, comprises a resilient sealing member 3 in which is engaged a plug 2 having a lateral projection(s) 4 which causes the resilient sealing member 3 to bunch up and generate transverse forces against the inside walls of the container 1 when an attempt is made to remove the sealing arrangement from the container. The arrangement is easily inserted into the container 1 because during insertion the resilient sealing member 3 is elongated. A passage through the plug for accommodating wires 9 is, provided with ratchet shaped strain relief projections 15. A rubber sealing cap 7 fits over the end of container 1 which is ceramic, and a coaxial glass container 6. <IMAGE>

Description

SPECIFICATION A sealing arrangement The present invention relates to sealing arrangements, and particularly to sealing arrangements used for providing water tight seals for containers housing water heaters.

Such seals may be used for sealing cable entries into such containers or for providing seals between such containers and second containers housing thermostats.

Known such seals generally comprise simple rubber bungs held in position with plastic locking pins. They tend to be difficult, and therefore costly, to assemble.

According to the present invention there is provided a sealing arrangement comprising a plug engaged in a sealing member of resilient material, said plug having lateral projecting portions engaging the resilient member so as to oppose removal of the sealing arrangement from a container to be sealed by generating transverse forces in the resilient sealing member against the inside walls of the container in response to a force being exerted on said plug in a direction to tend to remove the arrangement from the container.

A sealing arrangement according to the present invention can be constructed so that when it is positioned in a container to be sealed it provides a water-tight seal and is sufficiently difficult to remove to comply with the safety requirements of British Standards.

According to a preferred embodiment of the present invention the leading edges of the lateral projecting portions taper towards the end of the plug which is first inserted into a container to be sealed so as to facilitate assembly of a container sealed with an arrangement according to the present invention.

The sealing arrangement may have a passage, preferably formed through the plug, for receiving a cable coupling the zone inside to the zone outside a container to be sealed with the arrangement, and then the resilient sealing member is adapted to seal against a cable passed through the or each passage substantially to prevent ingress of water through the or each passage. This passage preferably has at least one ratchet shaped projection for deforming a cable passed through it so as to oppose removal of such a cable.

According to a first embodiment of the present invention the sealing arrangement may be provided with a part which projects laterally to sit on the edge of a container to be sealed.

According to another embodiment of the present invention the plug of the sealing arrangement is integral with a second container which may be an insulating sleeve housing a thermostat.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made to the accompanying drawings, in which: Figure 1 shows a container sealed with an arrangement according to a first embodiment of the present invention; Figure 2 shows a container sealed with an arrangement according to a second embodiment of the present invention.

Fig. 1 shows a container 1 which is a ceramic tube housing a heating element (not shown). Container 1 is sealed with an arrangement according to the present invention comprising a plug 2 engaged within a resilient sealing member 3. The plug 2 is in the form of a split cylinder moulded integrally with a disc shaped part 5 which sits on the edge of the container 1. Projecting parts 4, continuous round each part of the split cylinder, are formed at one end of the plug 2 and project laterally into the sealing member 3. The sealing member 3 is in the form of a hollow cylinder and surrounds the plug 2.

The container 1 is coaxially enclosed in a glass tube 6. The open end of the glass tube 6 is sealed by a rubber cap 7 which is secured in position with a cable tie 8.

Wires 9 for connection to the element in the ceramic tube 1 pass through a passage 10 formed in the disc shaped part 5 of the plug 2 and between the two halves of the split cylinder. Teets 11 and 12 on the cap 7 and the sealing member 3 respectively seal round these wires 9.

To assemble the container and the sealing arrangement as shown in Fig. 1, the plug 2 engaged in the sealing member 3 is pressed into the ceramic tube 1. This has the effect of elongating the sealing member 3 thereby reducing its diameter and making entry relatively easy. Once in position the resilience of the sealing member 3 causes it to revert to its original shape and to exert an outward pressure on the inside walls of the container 1 to form a water tight joint. Sloping faces 13 on the plug 2 further facilitate assembly.

When it is desired to remove the sealing arrangement from the container 1 however, a force exerted on the plug 2 in the direction of the arrow 14, i.e. to tend to remove it from the container 1, causes the projections 4 to bite into the resilient sealing member 3. This prevents the plug 2 slipping out of the member 3 and also causes the rubber of the sealing member 3 to bunch up to cause an outward pressure to be exerted on the inside walls of the container 1 so as to prevent the sealing member 3 slipping out of the ceramic tube 1. The more force that is exerted to part the sealing arrangement from the ceramic tube 1 the more outward pressure is generated to oppose the parting force.

The passage 10 for the wires 9 has internal projections 15 which are ratchet shaped, i.e.

they taper in a direction towards the inside of the ceramic tube 1. These projections 15 deform the wires 9 so as to oppose their removal.

Fig. 2 shows a second embodiment of the present invention. Container 1, being a ceramic tube housing a heating element (not shown), is sealed with an arrangement according to the present invention wherein the plug 2 is integral with an insulating sleeve 16 housing a thermostat (not shown). This embodiment works in exactly the same way as the embodiment described with reference to Fig. 1. However, in this embodiment the passage 10 through the plug 2 accommodating wires 9 does not have the projections 15 shown in Fig. 1 as there is less likelihood of the wires 9 being put under strain in this embodiment. Both the ceramic tube 1 and the insulating sleeve 16 are coaxially enclosed by a glass container 6.

The plug 2 in Fig. 2 is a simple cylinder, and the projections 4 are continuous round an annulus of this cylinder. In Fig. 1 however, the plug 2 is moulded as a disc shaped part 5 with a split cylinder extending therefrom, because this form facilitates manufacture as it is easier to mould in one piece than a simple cylinder because of the ratchet shaped cable strain relief projections 15.

The resilient sealing member 3 may be formed as a moulded unit in situ round the plug 2.

In the described embodiment the walls of the hollow cylindrical sealing member 3 have been given a thickness no less than a quarter, and preferably no less than a third, of the internal diameter of the sealing member, in the unstressed condition, that is when it is not sealing a container and not engaged in the plug 2. The radial extent of the projections 4 has also been chosen to be no less than an 1/6 and preferably no less than a quarter or a third the thickness of the wall of the sealing member.

In the described embodiment the projections 4 present planar surfaces 17 oriented perpendicularly to the longitudinal axis of the plug 2, and facing away from the leading end of the plug, i.e. in the direction 14. However, these surfaces 17 may be inclined at an angle, preferably in the direction 14. They may be inclined in the opposite direction at up to say 30 , but preferably no more than 20 , to the normal to the longitudinal axis of the cylinder part of the plug 2. The exact angle to which the surfaces 17 may be inclined in the opposite direction is of course also dependent on the relative dimensions of the wall of the sealing member 3 and the radial extent of projections 4 as discussed above.It will of course be obvious that the bigger the projections 4 relative to the thickness of the wall 3, the greater this angle of inclination may be.

The surfaces 17 can function correctly if they are curved, though in general the point on the projection 4 which is most displaced laterally from the main part of the plug 2 should preferably not lie significantly nearer the leading end of the plug than on a line which extends through the point at which the surface 17 meets the main part of the plug and which is tilted at an angle of 30 , preferably less than 20 , to the normal to the longitudinal axis of the plug.

It will be appreciated that in constructing a sealing arrangement according to the present invention account should also be taken of the resilience of the sealing member, the configuration and material composure of the inside wall of the container to be sealed, i.e. the friction between the sealing member and the container, and of course of the relative sizes of the diameter of the sealing arrangement and the inside diameter of the container.

CLAIMS (16 May 1979) 1. A sealing arrangement comprising a plug engaged in a sealing member of resilient material, said plug having lateral projecting portions engaging the resilient member so as to oppose removal of the sealing arrangement from a container to be sealed by generating transverse forces in the resilient sealing rnsm- ber against the inside walls of the container in response to a force being exerted on said plug in a direction to tend to remove the arrangement from the container.

2. A sealing arrangement according to claim 1 comprising at least one passage for receiving a cable coupling the zone inside to the zone outside a container to be sealed with said arrangement, wherein the sealing member is adapted to seal against a cable passed through the or each passage substantially to prevent ingress of water through the or each passage.

3. A sealing arrangement according to claim 2 wherein said passage is formed through said plug.

4. A sealing arrangement according to claim 2 or claim 3, wherein said passage has at least one ratchet shaped projection for deforming a cable passed through the passage so as to oppose removal of said cable.

5. A sealing arrangement according to any one of claims 2 to 4 wherein said passage has a projection cooperable with an oppositely positioned recess to deform a cable passed through the passage so as to oppose removal of said cable.

6. A sealing arrangement according to any one of claims 1 to 5 wherein said lateral projection portions are integral with said plug and form a continuous annular projection round said plug.

7. A sealing arrangement according to any one of claims 1 to 6 wherein said portions project laterally from said plug at a position located nearer that end of the plug which is first inserted into a container to be sealed

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Claims

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deform the wires 9 so as to oppose their removal.

Fig. 2 shows a second embodiment of the present invention. Container 1, being a ceramic tube housing a heating element (not shown), is sealed with an arrangement according to the present invention wherein the plug 2 is integral with an insulating sleeve 16 housing a thermostat (not shown). This embodiment works in exactly the same way as the embodiment described with reference to Fig. 1. However, in this embodiment the passage 10 through the plug 2 accommodating wires 9 does not have the projections 15 shown in Fig. 1 as there is less likelihood of the wires 9 being put under strain in this embodiment. Both the ceramic tube 1 and the insulating sleeve 16 are coaxially enclosed by a glass container 6.

The plug 2 in Fig. 2 is a simple cylinder, and the projections 4 are continuous round an annulus of this cylinder. In Fig. 1 however, the plug 2 is moulded as a disc shaped part 5 with a split cylinder extending therefrom, because this form facilitates manufacture as it is easier to mould in one piece than a simple cylinder because of the ratchet shaped cable strain relief projections 15.

The resilient sealing member 3 may be formed as a moulded unit in situ round the plug 2.

In the described embodiment the walls of the hollow cylindrical sealing member 3 have been given a thickness no less than a quarter, and preferably no less than a third, of the internal diameter of the sealing member, in the unstressed condition, that is when it is not sealing a container and not engaged in the plug 2. The radial extent of the projections 4 has also been chosen to be no less than an 1/6 and preferably no less than a quarter or a third the thickness of the wall of the sealing member.

In the described embodiment the projections 4 present planar surfaces 17 oriented perpendicularly to the longitudinal axis of the plug 2, and facing away from the leading end of the plug, i.e. in the direction 14. However, these surfaces 17 may be inclined at an angle, preferably in the direction 14. They may be inclined in the opposite direction at up to say 30 , but preferably no more than 20 , to the normal to the longitudinal axis of the cylinder part of the plug 2. The exact angle to which the surfaces 17 may be inclined in the opposite direction is of course also dependent on the relative dimensions of the wall of the sealing member 3 and the radial extent of projections 4 as discussed above.It will of course be obvious that the bigger the projections 4 relative to the thickness of the wall 3, the greater this angle of inclination may be.

The surfaces 17 can function correctly if they are curved, though in general the point on the projection 4 which is most displaced laterally from the main part of the plug 2 should preferably not lie significantly nearer the leading end of the plug than on a line which extends through the point at which the surface 17 meets the main part of the plug and which is tilted at an angle of 30 , preferably less than 20 , to the normal to the longitudinal axis of the plug.

It will be appreciated that in constructing a sealing arrangement according to the present invention account should also be taken of the resilience of the sealing member, the configuration and material composure of the inside wall of the container to be sealed, i.e. the friction between the sealing member and the container, and of course of the relative sizes of the diameter of the sealing arrangement and the inside diameter of the container.

CLAIMS (16 May 1979)

1. A sealing arrangement comprising a plug engaged in a sealing member of resilient material, said plug having lateral projecting portions engaging the resilient member so as to oppose removal of the sealing arrangement from a container to be sealed by generating transverse forces in the resilient sealing rnsm- ber against the inside walls of the container in response to a force being exerted on said plug in a direction to tend to remove the arrangement from the container.

2. A sealing arrangement according to claim 1 comprising at least one passage for receiving a cable coupling the zone inside to the zone outside a container to be sealed with said arrangement, wherein the sealing member is adapted to seal against a cable passed through the or each passage substantially to prevent ingress of water through the or each passage.

3. A sealing arrangement according to claim 2 wherein said passage is formed through said plug.

4. A sealing arrangement according to claim 2 or claim 3, wherein said passage has at least one ratchet shaped projection for deforming a cable passed through the passage so as to oppose removal of said cable.

5. A sealing arrangement according to any one of claims 2 to 4 wherein said passage has a projection cooperable with an oppositely positioned recess to deform a cable passed through the passage so as to oppose removal of said cable.

6. A sealing arrangement according to any one of claims 1 to 5 wherein said lateral projection portions are integral with said plug and form a continuous annular projection round said plug.

7. A sealing arrangement according to any one of claims 1 to 6 wherein said portions project laterally from said plug at a position located nearer that end of the plug which is first inserted into a container to be sealed than the other end of the plug.

8. A sealing arrangement according to any one of claims 1 to 7 wherein said plug has a part which tapers towards the end of the plug which is first inserted into a container to be sealed and said portions have ratchet shaped parts for engaging said resilient sealing member.

9. A sealing arrangement according to any one of the preceding claims provided with a part which projects laterally to sit on the edge of a container to be sealed.

10. A sealing arrangement according to any one of claims 1 to 8 wherein said plug is integral with a second container.

11. A container sealed with an arrangement according to any one of claims 1 to 10.

12. A container according to claim 11 which is a ceramic tube housing a heating element.

13. A container according to claim 12 when appended to claim 9, coaxially accommodated in a glass tube, wherein there is provided a resilient sealing cap for fitting over the sealed end of the sealed container and over one end of the glass tube, said sealing cap having a passage for accommodating and sealing against a cable coupling the zone inside to the zone outside said container.

14. A container according to claim 12 when appended to claim 10 wherein said second container is an insulating sleeve housing a thermostat.

15. A sealing arrangement substantially as hereinbefore described with reference to Fig.

1 or Fig. 2 of the accompanying drawings.

CLAIMS (29 Apr 1980)

1. A sealing arrangement comprising a plug engaged in a sealing member of resilient material, said plug having integral lateral projecting portions engaging the resilient member so as to oppose removal of the sealing arrangement from a container to be sealed by generating transverse forces in the resilient sealing member against the inside walls of the container in response to a force being exerted on said plug in a direction to tend to remove the arrangement from the container.