GB1572694A

GB1572694A - Method of and apparatus for sealing joints in pressurised conduits

Info

Publication number: GB1572694A
Application number: GB4071075A
Authority: GB
Original assignee: Press W & Son Ltd
Current assignee: Press W & Son Ltd
Priority date: 1975-10-04
Filing date: 1975-10-04
Publication date: 1980-07-30
Also published as: BE846936A; ES452169A1; DE2644742A1; AU1838676A; IT1072973B; NL7610976A; FR2326652A1; FR2326652B3

Description

(54) METHOD OF AND APPARATUS FOR SEALING JOINTS IN PRESSURISED CONDUITS (71) We, WILLIAM PRESS & SON LIMITED, a British Company, of 22 Queen Anne's Gate, Westminster, London, SW1H 9AH, 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: This invention relates to a method of and apparatus for sealing joints in pressurised conduits, for example, gas mains.

Hitherto, in order to seal a gas main a sealant such as diethylene glycol was sprayed at low pressure from a P.V.C. hose introduced into the main through a hole cut in the main. In carrying out this method, the gas supply to the gas main was disconnected. If the supply was not disconnected a considerable quantity of gas escaped during the spraying process.

It is an object of the present invention to provide a method of and apparatus for sealing joints in gas mains and like conduits without disconnecting the gas supply whereby the escape of gas from the main is greatly reduced or eliminated during the sealing process and wherein the joints are sprayed at high pressure and are thus sealed more efficientlv.

According to the present invention there is provided a method of sealing joints in a pressurised conduit, comprising the steps of providing a stand pipe branched from the conduit, fitting to the stand pipe an adaptor having a through passage and a valve member controlling flow through said through passage, passing a spraying hose through the adaptor into the conduit with a closure member on the hose closing the free end of the adaptor, and spraying the interior of the conduit with a sealant through the hose.

The invention also provides apparatus for use in carrying out the method of the preceding paragraph, comprising a stand pipe branched from the conduit, an adaptor releasably secured to the free end of said stand pipe and having a through-passage opening into the stand pipe, a hose for the sealant extending through the adaptor passage and the stand pipe into the conduit, a closure member on the hose closing the free end of the adaptor passage, a valve member in the adaptor passage in a valve-open position and movable to a valve-closed positon when the hose is withdrawn, and a control for said valve member.

Embodiments of the present invention will now be described by way of example with reference to the accompanying draw ings in which: Figure 1 is a diagrammatic view, in perspective, of apparatus for sealing joints in gas mains; and Figures 2-13 show the various steps and the apparatus used in carrying out the method according to the present invention.

Referring to Figure 1, apparatus for sealing joints in gas mains comprises a main storage tank 1 containing sealant, usually diethylene glycol and known under the name "Weasel" (Trade Mark). The sealant in the main storage tank 1 is transferred to a header tank 2 by means of a hand pump 3.

The header tank is provided with gauge means 4 in order that the quantity of sealant may be monitored.

The sealant in the header tank is then fitted to a high pressure pump 5 the output of which is fed through a high pressure hose 6 to a spraying nozzle (not shown). One example of a high pressure hose has an inside diameter of 3/s" and receives sealant from the pump 5 at a pressure of 4,000 p.s.i.

The pump is fitted with a pressure gauge and a sealant return conduit 8.

The method according to the present invention will now be described with refer ence to Figures 2-13.

A first valve 11 is secured, by means of a chain 9, to a main 10 to be sealed or to a collar 12 fitted to a small diameter main 10a.

A boring fixture, shown generally at 13, is screwed on to the valve 11 and the valve is then opened to allow a drill 14 of the boring fixture 11 to be fed onto the main 10. A hole is then bored in the main 10, the drill is withdrawn, the valve 11 is closed and the boring fixture 13 is unscrewed. (Figures 2 and 3).

A stand pipe 15 having a plug 16 is introduced into the valve 11 through a seal boss 17. The valve 11 is again opened and the stand pipe is screwed into the main 10.

The chain 9 may then be loosened and the valve 11 removed by sliding the valve up the fitted and sealed stand pipe 15 (Figures 4 and 5).

In order to replace the expanding plug 16 with a screwed plug 18, a screw-threaded bush 20 is fitted to the stand pipe 15 and a valved conduit or adaptor in the form of a plastic valve 21 is screwed on to the bush 20.

A seal cap 22 with a drive member 23 having a squared end 24 is fitted to the valve 21 and the valve 21 is then opened to allow the expanding plug to be removed from the stand pipe 15. The plug 16 is withdrawn past the valve 21 and the valve is closed. The seal cap 22 can then be removed from the valve 21. A screwed plug 18 is then fitted to a socket 25 on the squared end 24 of the member 23, the seal cap 22 is re-fitted to the valve 21, the valve 21 is opened and the screwed plug 18 fitted to the stand pipe 15 thus sealing the stand pipe. The valve 21 may then be removed. (Figures 6-9).

The spraying of the joints of the main 10 may now be effected. By carrying out, in the reverse order, the steps described in the last preceding paragraph, the screwed plug 18 may be removed from the stand pipe 15, which is, at that stage, fitted with the plastic valve 21 (Figure 10). A seal cap 22a adapted to receive a sheath 26 is then fitted to the valve 21 (Figure 11). The valve 21 is opened and the sheath, together with the high pressure spraying hose 6 is fed into and along the main 10 in one direction and the main 10 is sprayed with sealant. The hose 6 and sheath 26 are partially withdrawn and the sheath 26 is turned though 1800 so that the hose 6 is fed along the main 10 in the other direction, as shown in Figure 12.

When spraying is completed, the hose 6 and sheath 26 are withdrawn past the valve 21. the valve 21 is closed and the seal cap 22a is removed.

As described earlier, the screwed plug 18 is re-fitted and the plastic valve 21 removed, thus resulting in a closed stand pipe 15 as shown in Figure 13.

By carrying out the steps of the method according to the present invention, gas mains may be sealed efficiently and with substantially no leakage of gas.

WHAT WE CLAIM IS: 1. A method of sealing joints in a pressurised conduit, comprising the steps of providing a stand pipe branched from the conduit, fitting to the stand pipe an adaptor having a through passage and a valve member controlling flow through said through passage, passing a spraying hose through the adaptor into the conduit with a closure member on the hose closing the free end of the adaptor, and spraying the interior of the conduit with a sealant through the hose.

2. A method as claimed in claim 1, and including the step of fitting the stand pipe to the conduit by securing a valve to the conduit, attaching a boring fixture having a drill member to the said valve, opening said valve, passing said drill member through the valve to drill a hole in the conduit, withdrawing said drill member, removing said boring fixture, attaching a seal boss to said valve, inserting the stand pipe closed at one end by a plug into said seal boss in sealing relation therewith, opening said valve, screwing the stand pipe into the hole in the conduit main, and removing said valve and seal boss from the conduit.

3. A method as claimed in either claim 1 or 2, wherein said sealant is sprayed at a pressure of substantially 4,aOQ lb. per square inch.

4. Apparatus for use in carrying out the method of claim 1, comprising a stand pipe branched from the conduit, an adaptor releasably secured to the free end of said stand pipe and having a through-passage opening into the stand pipe, a hose for the sealant extending through the adaptor passage and the stand pipe into the conduit, a closure member on the hose closing the free end of the adaptor passage, a valve member in the adaptor passage in a valve-open position and movable to a valve-closed position when the hose is withdrawn, and a control for said valve member.

5. Apparatus according to claim 4, including a turnkey, a screw-threaded plug carried withdrawably on the free end of the shank of the turnkey, and a closure member slidably mounted on said shank, the arrangement being such that, when the hose is withdrawn from the adaptor, and the valve member then closed, the said closure member can be fitted to the free end of the adaptor, the valve member can then be opened and the plug can be fitted to the stand pipe by means of the turnkey, and the latter can be withdrawn, and the adaptor can be detached from the stand pipe.

6. A method of sealing joints in a gas main substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. chain 9, to a main 10 to be sealed or to a collar 12 fitted to a small diameter main 10a. A boring fixture, shown generally at 13, is screwed on to the valve 11 and the valve is then opened to allow a drill 14 of the boring fixture 11 to be fed onto the main 10. A hole is then bored in the main 10, the drill is withdrawn, the valve 11 is closed and the boring fixture 13 is unscrewed. (Figures 2 and 3). A stand pipe 15 having a plug 16 is introduced into the valve 11 through a seal boss 17. The valve 11 is again opened and the stand pipe is screwed into the main 10. The chain 9 may then be loosened and the valve 11 removed by sliding the valve up the fitted and sealed stand pipe 15 (Figures 4 and 5). In order to replace the expanding plug 16 with a screwed plug 18, a screw-threaded bush 20 is fitted to the stand pipe 15 and a valved conduit or adaptor in the form of a plastic valve 21 is screwed on to the bush 20. A seal cap 22 with a drive member 23 having a squared end 24 is fitted to the valve 21 and the valve 21 is then opened to allow the expanding plug to be removed from the stand pipe 15. The plug 16 is withdrawn past the valve 21 and the valve is closed. The seal cap 22 can then be removed from the valve 21. A screwed plug 18 is then fitted to a socket 25 on the squared end 24 of the member 23, the seal cap 22 is re-fitted to the valve 21, the valve 21 is opened and the screwed plug 18 fitted to the stand pipe 15 thus sealing the stand pipe. The valve 21 may then be removed. (Figures 6-9). The spraying of the joints of the main 10 may now be effected. By carrying out, in the reverse order, the steps described in the last preceding paragraph, the screwed plug 18 may be removed from the stand pipe 15, which is, at that stage, fitted with the plastic valve 21 (Figure 10). A seal cap 22a adapted to receive a sheath 26 is then fitted to the valve 21 (Figure 11). The valve 21 is opened and the sheath, together with the high pressure spraying hose 6 is fed into and along the main 10 in one direction and the main 10 is sprayed with sealant. The hose 6 and sheath 26 are partially withdrawn and the sheath 26 is turned though 1800 so that the hose 6 is fed along the main 10 in the other direction, as shown in Figure 12. When spraying is completed, the hose 6 and sheath 26 are withdrawn past the valve 21. the valve 21 is closed and the seal cap 22a is removed. As described earlier, the screwed plug 18 is re-fitted and the plastic valve 21 removed, thus resulting in a closed stand pipe 15 as shown in Figure 13. By carrying out the steps of the method according to the present invention, gas mains may be sealed efficiently and with substantially no leakage of gas. WHAT WE CLAIM IS:

1. A method of sealing joints in a pressurised conduit, comprising the steps of providing a stand pipe branched from the conduit, fitting to the stand pipe an adaptor having a through passage and a valve member controlling flow through said through passage, passing a spraying hose through the adaptor into the conduit with a closure member on the hose closing the free end of the adaptor, and spraying the interior of the conduit with a sealant through the hose.

7. Apparatus as claimed in claim 4, and

substantially as hereinbefore described with reference to the accompanying drawings.