GB2078899A

GB2078899A - Plug

Info

Publication number: GB2078899A
Application number: GB8116325A
Authority: GB
Original assignee: PRODUCTION ENG RES
Current assignee: PRODUCTION ENG RES
Priority date: 1980-06-06
Filing date: 1981-05-28
Publication date: 1982-01-13
Also published as: GB2078899B

Abstract

The invention relates to a plug for use in sealing an orifice or an outlet, for example, the end of a pipe, condenser tube or heat exchanger. The plug (8) has a main body portion (10) which is stiffly elastic and an internal cavity which has at least one mouth portion (18) and is frustoconical in shape. An insert (24) is received in a loose fit within the cavity at its widest region and is moved towards the narrowest region so as to push the cavity walls outwards and expand the body portion of the plug so that it seals the orifice. Where the plug (8) has only one orifice, pressurised fluid may be used to move the insert (24) into the operative position in which it is retained by the provision of a groove (20). <IMAGE>

Description

SPECIFICATION Plugging means The invention relates to plugging means for closing or stopping orifices, outlets or the like.

It may frequently be necessary to plug an orifice of a chamber, an outlet of a vessel ortho open end of a tube or pipe, and in doing so, to ensure as tight a seal as is practicable. For example, in a condenser or heat exchanger it may be desirable to plug one or more of the tubes thereof, in as efficient a manner as possible, in the event that the tubes become faulty and develop leaks.

The invention provides a plugging means for use in sealing an orifice, outlet or the like comprising a main body portion of stiffly elastic material, a cavity within said body portion having a frustoconical wall surface tapering towards a mouth portion at a region thereof having a cross-dimension less than that at its widest cross-dimension, and an insert member received in a loose fit in the cavity at its region of widest cross-dimension and receivable in a force fit in a region adjacent the mouth portion the construction and arrangement being such that the presence of the insert member at the said region adjacent the mouth portion causes the external diameter of the body portion in that region to increase compared to its diameter in an unstressed condition when the insert member is a loose fit in the cavity.

Conveniently a retaining groove or shoulder may be provided at said region adjacent the mouth portion in order to keep the insert member in position during use.

However, it may be required that the plugging of, for instance, a pipe end, should be only temporary, and that, because of the length of the pipe, the orifice is, to all intents and purposes, blind. Therefore it is desirable that in some examples, both insertion and removal of the plug is achievable from one side only.

Conveniently, therefore, the plug may further comprise an end portion providing a base wall for said body portion to close one end of the cavity arranged at the opposite end region of the cavity to said mouth portion, the walls of the cavity tapering inwards from a widest cross-dimension adjacent the base wall towards said mouth portion, means being provided for forcing the insert membertowardsthe mouth portion from a loose-fitting position adjacent the base wall.

In a preferred example, said means to force movement of the insert member comprise an aperture in the insert member, a nozzle capable of passing through said aperture in said insert member and supplying fluid under pressure to that region of the cavity between the base wall and the confronting surface of the insert member, to force the latter to move away from said base wall. The fluid may be compressed air or other gas, or may be a suitable hydraulic fluid.

Advantageously, the insert member may be in the form of a frustocone the walls of which taper at an angle identical to that of the tapering cavity walls, the aperture therein lying along the axial centre line of the cone.

The invention further provides a method of plugging an orifice or outlet in a structure or member, comprising a plug formed of stiffly elastic material and having an internal cavity, said cavity having a mouth of a diameter smaller than that of the remainder of the cavity, inserting the plug into the cavity and introducing into said cavity a fluid under pressure so that an insert member received in said cavity is forced into a wedging position against the walls of the cavity such that the outside diameter of the plug walls is slightly increased due to the presence of the insert member in said wedging position, which member remains in position after the pressurised fluid escapes.

There will now be described an example of a plug which is inserted in an open end of a tube or pipe according to the method of the invention. It will be understood that the description which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 shows a plug during a step in the method of insertion thereof into an open end of a tube; Figure 2 shows the tube and plug of Figure 1 after the positioning of the insert with the end of a nozzle and Figure 3 shows the same tube and plug after removal of the nozzle.

A tube 2, which in the present example is one of several thousand tubes supported in the walls of a condenser, is shown in Figure 1 and is provided with a liner 4 according to conventional practice to minimise wear. There is no need to remove the liner prior to plugging according to the invention. The open end of the tube is supported in a wall plate 6 of the condenser.

A plug, indicated generally at 8, is shown placed in position in the open end of the tube 2 and comprises a cylindrical body portion 10, with a hemispherical end portion 12 and, lying adjacent the lip of the tube, a flange portion 14.

A cavity 16 is provided in the body portion 10 of the plug 2, having a mouth portion 18 centrally disposed with respect to the flange portion 14. The cavity is tapered and has a generally conical configuration, the mouth portion 18 being at the apex thereof. A groove 20 is formed in the wall of the cavity inwardly, but in the vicinity, of the mouth portion 18.

A A nozzle 22 is shown inserted into the cavity 16 in order to supply compressed air from a source (not shown). The end portion of the nozzle passes through a central aperture in an insert member 24 captive in the cavity. The insert member 24 is a frustocone the sides of which have the same angle of slope as do the walls of the tapered cavity shown in Figure 1,that is 100 from the axial centre line in the present example.

The effect of supplying compressed air to the cavity at a region between the portion 12 and the insert member (as viewed in Figure 1) is two-fold.

Firstly, the ingress of pressurised air into the cavity 16 has the effect of forcing the insert member away from the base wall of the cavity and towards the mouth portion thereof. Secondly, the reaction effect of this is to cause the plug to become seated more firmly in the tube, so that the flange portion 14 seats against the lip ofthetube.

As the insert member 24 is forced upwardly (as viewed in the Figures) in the cavity, the walls thereof are gradually pushed outwards due to the continuing wedging action of the member 24. Thus the cavity walls tend to assume a more nearly cylindrical configuration as shown in Figure 2. This tends to increase the internal diameter of the cavity in the region of the groove 20 and as it does so, the diameter of the groove itself is increased sufficiently to allow the insert member 24 to enterthe groove as shown in Figure 2. By now, the increased external diameter of the plug has produced a firm, water-tight seal at the open end of the tube 4. When the air-pressure is released and the nozzle 22 withdrawn, the seal is maintained as shown in Figure 3 since the insert member 24 is retained in place in the groove and cannot be accidentally removed.

However, when it is desired to remove the plug 8 from the end of the tube, a narrow instrument may be inserted through the aperture 18 ti impart a percussive blow to the insert, sufficient to dislodge it from the groove and return it to the position shown in Figure 1. The plug may then be easily removed from the end of the tube 4.

Various modifications may be made within the scope of the invention as defined by the following

Claims

claims. CLAIMS

1. A plugging means for use in sealing an orifice, outlet or the like comprising a main body portion of stiffly elastic material, a cavity within said body portion having a frustoconical wall surface tapering towards a mouth portion at a region thereof having a cross-dimension less than that at its widest crossdimension, and an insert member received in a loose fit in the cavity at its region of widest crossdimension and receivable in a force fit in a region adjacent the mouth portion, the construction and arrangement being such that the presence of the insert member at said region adjacent the mouth portion causes the external diameter of the body portion in that region to increase compared to its diameter in an unstressed condition when the insert member is a loose fit in the cavity.

2. A plugging means as claimed in Claim 1, wherein a retaining shoulder is provided at said region adjacent the mouth portion.

3. A plugging means as claimed in Claim 2, wherein the retaining shoulder forms part of an annular or part-annular groove formed in the cavity wall surface.

4. A plugging means as claimed in any one of the preceding claims, further comprising an end portion providing a base wall for said body portion to close one end of the cavity arranged at the opposite end region of the cavity to said mouth portion, the walls of the cavity tapering inwards from a widest crossdimension adjacent the base wall towards said mouth portion, means being provided from a loosefitting position adjacent the base wall.

5. A plugging means as claimed in Claim 4, wherein the means for forcing the insert members towards the mouth portion comprise an aperture in the insert member, a nozzle capable of passing through the said aperture in said insert member and supplying fluid under pressure to that region of the cavity between the base wall and the confronting surface of the insert member, to force the latter to move away from said base wall.

6. A plugging member as claimed in any one of the preceding claims wherein the insert member is in the form of a frustocone the walls of which taper at an angle identical to that of the cavity walls.

7. A method of plugging an orifice or outlet in a structure or member, comprising a plug formed of stiffly elastic material and having an internal cavity, said cavity having a mouth of a diameter smaller than that of the remainder of the cavity, inserting the plug into the cavity and introducing into said cavity a fluid under pressure so that an insert member received in said cavity is forced into a wedging position against the walls of the cavity such that the outside diameter of the plug walls is slightly increased due to the presence of the insert member in said wedging position, which member remains in position after the pressurised fluid escapes.

8. A method of plugging an orifice or outlet as claimed in Claim 7, wherein the pressurised fluid is air.

9. A method of plugging an orifice or outlet as claimed in Claim 7, wherein the pressurised fluid is hydraulic fluid.

10. A plugging means for use in sealing an orifice or outlet, constructed and arranged substantially as hereinbefore described with reference to and as shown in the drawings.

11. A method of plugging an orifice or outlet substantially as hereinbefore described with reference to the drawings.