GB1563762A

GB1563762A - Plug

Info

Publication number: GB1563762A
Application number: GB34249/77A
Authority: GB
Original assignee: Furmanite International Ltd
Current assignee: Furmanite International Ltd
Priority date: 1977-08-16
Filing date: 1977-08-16
Publication date: 1980-04-02
Also published as: CA1076979A; ZA781477B

Description

(54) PLUG (71) We, FURMANITE INTERNATIONAL LIMITED, a British Company, of Dockray Hall Road, Kendal, Cumbria, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to tube or bore plugging and has particular, but not exclusive, application to isolating defective heat exchanger tubes.

Heat exchangers are widely used in many processes having applications in the chemical and power supply industries. A conventional construction of heat exchangers may make use of a housing vessel having, or fitted with, flanging to which a plurality of U-shaped tubes are fitted to carry heat exchanger fluid. These tubes may have to withstand substantial pressures, say up to 2000 psi. Where such tubes develop leaks, whether due to corrosion or for other reasons, it has been a common practice to plug them with a wedge driven into an end of a defective tube, but with only moderate success.

Our copending application no. 6692/76 (Serial No. 1,518,425) provides for plugging by way of a plug comprising a deformable sleeve to fit inside a bore to be plugged, the sleeve being circumferentially continuous at least at its ends, two tapered members interfitting with the sleeve to engage opposite ends thereof and also fit inside the bore to be plugged, and means intercoupling the tapered members whereby they are drawn together to deform the sleeve into circumferential engagement with the interior of the bore at each end of the sleeve. Specifically, the sleeve has an external ridge at or near each of its ends shaped to co-act with the tube or bore wall on spreading of the sleeve by the tapers and assist in deforming the sleeve by buckling inwardly at its mid-region. A substantially central carrier member may have bores so as to allow injection of a flowable sealing compound therethrough and through apertures in the sleeve.

The present invention arises from our preference to develop this plug using corrosion resistant materials, such as stainless steel, and we have found that, such materials tending to be relatively hard, the sleeve ridges have themselves bitten into the material of the bore to be plugged, especially if tapered to an edge, and usually resulted in the achievement of a satisfactory seal without sealant introduction. Furthermore, only the sleeve-end furthest into the bore need be so formed and advantages arise, by way of resistance to vibration-loosening, if a flange, which may be integral with the other end part of the sleeve, is provided to bear against the end of the bore to be plugged.

According to one aspect of the invention there is provided a method of plugging a bore, comprising the steps of inserting into the bore a deformable sleeve having a tapered member engaged in its inserted end whereat the sleeve is circumfrentially continuous and has an external circumferentially continuous rib proud of the sleeve that extends therefrom, producing relative movement of the sleeve and tapered member to force the latter into the former and spread the rib, and continuing such movement sufficiently to circumferentially engage and locally deform the wall of the bore.

A suitable bore plug comprises a deformable sleeve to fit inside a bore to be plugged, a tapered member to fit inside said bore and interfit with the sleeve at one end whereat the sleeve is circumferentially continuous and has an external rib also circumferentially continuous and proud of the sleeve exterior extending away therefrom, and means for intercoupling the sleeve and the tapered member to produce relative movement drawing the latter into the sleeve and spreading the ribbed end so that the rib is forced yet wider than the rest of the sleeve into circumferential engagement with and locally deforming the bore-wall.

One preferred embodiment of this invention therefore comprises an inner member carrying or integral with a tapered member for entering and spreading a tooth-section ridged end part of a surrounding sleeve having, preferably integral therewith, a flange at a spaced position, typically its other end. Then, means for acting between the inner member and the flange, such as a nut on a threaded end of the inner member where it protrudes through the flange on the non-sleeve side to bear against such flange, serves in drawing the tapered part into the sleeve. In such a structure, especially where the flange is integral with the sleeve, further protection against vibration loosening is provided where the nut enters a necklike extension from the flange which extension can be struck, say with a hammer, to deform into locking engagement with flats of the nut. Such, or analagous provision is, of course, equally, applicable to other types of tube plug having relatively movable parts, for example that of our above-mentioned application.

One embodiment of the invention will now be specifically described by way of example, with reference to the accompanying drawing, in which: Figure 1 is a sectional view of a tube plug; Figure 2 is another sectional view similar to Figure 1 but showing the tube plug operated to seal a bore; and Figure 3 is an end view of the plug of Figure 1.

In the drawings, an end-spreadable sleeve 10 is, when unspread, capable of sliding inside a tube or bore 11 to be plugged. An inner member or spindle 12 has clearance 13 within the sleeve 10 except for a tapered head or end 14 for spreading the sleeve 10 at its end 15 where an external rib 16 has external surfaces converging towards the end 15 from an edge 18. At its other end, the sleeve 10 has an exterior flange 20 beyond a sleeve part 21 exteriorly thickened, usually to the same initial diameter as that of the rib, but perhaps to the nominal diameter of the tube or bore to be plugged, if different. The central, thinner wall portion 22 of the sleeve materially assists inward buckling thereof when the sleeve-end 15 is spread and its rib-like rim 16 engages the bore 11 to be plugged.

The spindle 12 extends through the flange 20 and is threaded at 24 to be engaged by a nut 25 which, on seating on the flange 20, will serve in drawing the spindle into the sleeve and thus spreading end 15 thereof.

The flange 20 provides ready seating against the end of the bore to be plugged, typically against a flange of a heat exchanger housing vessel, and its area of contact therewith ensures good stability and resistance to vibration effects.

About the position at which the nut 25 seats on the flange the latter has a thinwalled neck or collar extension 28 that is deformable, say by hammer blows, to lock the nut 25 in a tightened position.

In fitting, see Figure 2, the spreading of the sleeve end 15 caused by tightening of the nut 25 causes, for a sufficiently hard material of the sleeve, the edged rib or rim 16 to bite into the interior surface of the material defining the bore or tube to be plugged. Such action is normally sufficient to provide a satisfactory seal. Where this does not occur say due to the interior of the bore being badly corroded, or the material defining it being too hard, provision may be made for injection of sealing compound such as one of the "Furmanite" (Registered Trade Mark) leak sealing compounds via apertures in the sleeve, either from a blind longitudinal bore of the inner member or spindle and intersecting crossbores to the sleeve apertures as in our abovementioned application, or by injection through a nipple or other provision at the flange.

WHAT WE CLAIM IS: 1. A method of plugging a bore, comprising the steps of inserting into the bore a deformable sleeve having a tapered member engaged in its inserted end whereat the sleeve is circumferentially continuous and has an external circumferentially continuous rib proud of the sleeve that extends therefrom, producing relative movement of the sleeve and tapered member to force the latter into the former and spread the rib, and continuing such movement sufficiently to circumferentially engage and locally deform the wall of the bore.

2. A bore plug for carrying out the method of claim 1, comprising a deformable sleeve to fit inside a bore to be plugged, a tapered member to fit inside said bore and interfit with the sleeve at one end whereat the sleeve is circumferentially continuous and has an external rib also circumferentially continuous and proud of- the sleeve extending away therefrom, and means for intercoupling the sleeve and the tapered member to produce relative movement drawing the latter into the sleeve and spreading the ribbed end so that the rib is forced yet wider than the rest of the sleeve into circumferential engagement with and locally deforming the bore-wall.

3. A bore plug according to claim 2,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tapered member to produce relative movement drawing the latter into the sleeve and spreading the ribbed end so that the rib is forced yet wider than the rest of the sleeve into circumferential engagement with and locally deforming the bore-wall. One preferred embodiment of this invention therefore comprises an inner member carrying or integral with a tapered member for entering and spreading a tooth-section ridged end part of a surrounding sleeve having, preferably integral therewith, a flange at a spaced position, typically its other end. Then, means for acting between the inner member and the flange, such as a nut on a threaded end of the inner member where it protrudes through the flange on the non-sleeve side to bear against such flange, serves in drawing the tapered part into the sleeve. In such a structure, especially where the flange is integral with the sleeve, further protection against vibration loosening is provided where the nut enters a necklike extension from the flange which extension can be struck, say with a hammer, to deform into locking engagement with flats of the nut. Such, or analagous provision is, of course, equally, applicable to other types of tube plug having relatively movable parts, for example that of our above-mentioned application. One embodiment of the invention will now be specifically described by way of example, with reference to the accompanying drawing, in which: Figure 1 is a sectional view of a tube plug; Figure 2 is another sectional view similar to Figure 1 but showing the tube plug operated to seal a bore; and Figure 3 is an end view of the plug of Figure 1. In the drawings, an end-spreadable sleeve 10 is, when unspread, capable of sliding inside a tube or bore 11 to be plugged. An inner member or spindle 12 has clearance 13 within the sleeve 10 except for a tapered head or end 14 for spreading the sleeve 10 at its end 15 where an external rib 16 has external surfaces converging towards the end 15 from an edge 18. At its other end, the sleeve 10 has an exterior flange 20 beyond a sleeve part 21 exteriorly thickened, usually to the same initial diameter as that of the rib, but perhaps to the nominal diameter of the tube or bore to be plugged, if different. The central, thinner wall portion 22 of the sleeve materially assists inward buckling thereof when the sleeve-end 15 is spread and its rib-like rim 16 engages the bore 11 to be plugged. The spindle 12 extends through the flange 20 and is threaded at 24 to be engaged by a nut 25 which, on seating on the flange 20, will serve in drawing the spindle into the sleeve and thus spreading end 15 thereof. The flange 20 provides ready seating against the end of the bore to be plugged, typically against a flange of a heat exchanger housing vessel, and its area of contact therewith ensures good stability and resistance to vibration effects. About the position at which the nut 25 seats on the flange the latter has a thinwalled neck or collar extension 28 that is deformable, say by hammer blows, to lock the nut 25 in a tightened position. In fitting, see Figure 2, the spreading of the sleeve end 15 caused by tightening of the nut 25 causes, for a sufficiently hard material of the sleeve, the edged rib or rim 16 to bite into the interior surface of the material defining the bore or tube to be plugged. Such action is normally sufficient to provide a satisfactory seal. Where this does not occur say due to the interior of the bore being badly corroded, or the material defining it being too hard, provision may be made for injection of sealing compound such as one of the "Furmanite" (Registered Trade Mark) leak sealing compounds via apertures in the sleeve, either from a blind longitudinal bore of the inner member or spindle and intersecting crossbores to the sleeve apertures as in our abovementioned application, or by injection through a nipple or other provision at the flange. WHAT WE CLAIM IS:

1. A method of plugging a bore, comprising the steps of inserting into the bore a deformable sleeve having a tapered member engaged in its inserted end whereat the sleeve is circumferentially continuous and has an external circumferentially continuous rib proud of the sleeve that extends therefrom, producing relative movement of the sleeve and tapered member to force the latter into the former and spread the rib, and continuing such movement sufficiently to circumferentially engage and locally deform the wall of the bore.

3. A bore plug according to claim 2,

wherein said intercoupling is via an inner member rigid with the tapered member and passing through the sleeve.

4. A bore plug according to claim 2 or 3, wherein the sleeve has an exterior flange spaced from its external rib and capable of seating against the bore end.

5. A bore plug according to claim 4 or claim 3, wherein a free end of the inner member is threaded to carry a nut cooperating with the flange to produce said relative movement.

6. A bore plug according to claim 5, wherein the flange has an annular extension from and about a seating position thereof for the nut.

7. A bore plug according to claim 5, wherein the annular extension is deformable by hammer blows to lock the nut.

8. A bore plug substantially as herein described with reference to and as shown in the drawing.