GB2514853A

GB2514853A - Sealant injection gun

Info

Publication number: GB2514853A
Application number: GB1310322.1A
Authority: GB
Inventors: Keith Frederick Baylis; Peter Michael Wardle
Original assignee: Chemence Ltd
Current assignee: Chemence Ltd
Priority date: 2013-06-08
Filing date: 2013-06-08
Publication date: 2014-12-10
Also published as: GB201310322D0

Abstract

A sealant injection gun 1 comprises a barrel 2 to receive a fluid under pressure, the barrel having a forward end with an opening to receive a cartridge 4 or container of sealant to form an air tight seal with the wall of the barrel, There is a piston 5 for engaging with the cartridge or container on forward movement of the piston to eject the sealant from the opening into a joint. There is a trigger 6 permitting the injection of the fluid into the barrel when the trigger is actuated so as to permit the fluid pressure to move the piston and prevent the injection of fluid into the barrel when the trigger is released. The trigger has means for connecting a fluid line to the trigger and there is a valve 15 adapted to control the flow of fluid to the piston, the valve being biased to close to prevent the flow of fluid to the piston but operable manually against the bias to open and permit the flow of fluid to the piston but only when the trigger has been actuated. The fluid may be air from an air-line. The valve may be a spool valve.

Description

Title: Sealant Injection Gun The present invention relates to an improved sealant injection gun for injecting a sealant particularly an anaerobic sealant into the mechanical joints of gas and other fluid carrying pipes and mains whereby the sealant injected in the form of a spray sets to form a seal and prevent the escape or leakage of gas or the particular fluid from the pipe joint.

One current standard type of sealant injection gun comprises a plunger rod to push a piston via a mechanically actuated trigger mechanism whereby the piston pushes the sealant from a cartridge or container also known as a sindle in which the sealant is held into the joint to seat it. unfortunately in this device it is only possible to move the rod a little at a time as the mechanical movement of the trigger is limited so that injection is slow. This is perfect for lead-yarn type joints found in gas pipes or mains where a long slow injection is required but some mechanical joints respond better to a "fire hose/shot gun" approach. In this technique the sealant is fired into the joint quickly as a spray so that the entire joint is surrounded by sealant. One type of gun designed to use this approach relies on a pressure pot powered from a nitrogen containing bottle but this means that the bottle must be transported from joint to joint. As such bottles are heavy and cumbersome to transport this gun has not found favour.

It is therefore an object of the present invention to provide a sealant injection gun in which th.e speed of injection is comparable with the nitrogen bottle method but without the * inconvenience of having to move a bottle from joint to joint for sealing. * *

It is also an object of the present invention to provide a sealant injection gun in which the : .. fluid is prevented from moving the piston to eject the sealant until the trigger is actuated * and a safety valve is opened.

According to one aspect of the present invention we provide a sealant injection gun : comprising a barrel to receive air under pressure, the barrel having a forward end with an * opening to receive a cartridge or container of sealant to form an air tight seal with the wall of the barrel, a piston for engaging with the cartridge or container on forward movement of the piston to eject the sealant from the opening into a joint, a trigger permitting the injection of air into the barrel when the trigger is actuated so as to permit the air pressure to move the piston and preventing the injection of air into the barrel when the trigger is released1 the trigger having means for connecting an air line to the trigger.

According to another aspect of the present invention we provide a sealant injection gun comprising a barrel to receive a fluid under pressure, the barrel having a forward end with an opening to receive a cartridge or container of sealant to form an air tight seal with the wall of the barrel, a piston for engaging with the cartridge or container on forward movement of the piston to eject the sealant from the opening into a joint, a trigger permitting the injection of the fluid into the barrel when the trigger is actuated so as to permit the fluid pressure to move the piston and prevent the injection of fluid into the barrel when the trigger is released, the trigger having means for connecting a fluid line to the trigger and a valve adapted to control the flow of fluid to the piston, the valve being biased to close to prevent the flow of fluid to the piston but operable manually against the bias to open and permit the flow of fluid to the piston but only when the trigger has been actuated.

Preferably the fluid is air and the fluid line is an air line.

Suitably there is a further piston rearward of the other piston and connected to the other piston by a rod, the fluid line terminating behind the further piston to cause the fluid pressure to move the further piston and thereby the other piston to eject the sealant.

Conveniently the trigger has a hollow body through which extends a fluid line which terminates behind the further piston, there being means within the trigger to connect and disconnect the fluid line to and from the further piston on movement of a handle with which the trigger is provided to actuate and release the trigger.

Preferably the valve is a spool valve.

An embodiment of the invention will now be described with reference to the accompanying drawing which shows an axial section of a sealant injection gun in accordance with.the claims.

Referring to the drawing the gun 1 comprises a hollow cylindrical barrel 2, an opening 3 at a : .. forward end to receive a cylindrical cartridge or container of sealant 4 to form an air tight * . seal with the internal wall of the barrel 1, a first forwardly located piston or plungers to * * engage the base of the cartridge 4 and on forward movement thereof engage and squeeze the cartridge 4 to expel the sealant into the joint to be sealed, a trigger 6 forming part of a : handle 7 whereby on closure and actuation of the trigger 6air from a compressed air source (not shown) is supplied via an air line or tube 8,9 to a conventional pressure regulator 9 (only the housing shown specifically) at the rear of the gun 1, a second rearwardly located piston 1]. which is connected to the first piston S by a connecting rod 12 and a conventional *..* : spool valve arrangement 13, the air line 9 terminating rearwardly of this valve 13 but in *. front of the pressure regulator 9, the spool valve 13 controlling the flow of air to the rearward piston 11 to cause it to flow when the valve 13 is open against a bias but not to flow when the valve 13 is closed.

The first piston 5 is moved by the connecting rod 12 when this is driven forward by air pressure on the rear of the rear piston 11 to eject the sealant from the cartridge. However the air pressure can only act on the rear piston 11 when the trigger 6 is closed and actuated and the spool valve 13 is open against the bias.

The spool valve 13 comprises a spindle 14 and a button 15 projecting from the wall of the barrel 2, the spindle 14 extending downwardly from the button 15 at the top to the bottom of that section. On the spindle 14 are discs 16, 17 carrying o' ring seals (not shown) and these discs 16,17 will pass across ports/holes 18 (only one hole shown) in a tube 19 in the valve 13 through which the air is supplied to the second piston 11. The spindle 14 is spring loaded to the up position and this is the off position. When the button 15 is depressed manually the spindle 14 is held down. If at the same time the trigger 6 is actuated to supply air behind the spool valve 13, the ports 18 or paths will be opened in the tube 19 to allow air to go through to the rear piston chamber and hence push the piston 11 down the rear part of the barrel 1. This movement will be transferred to the front piston 5 by the rod 11 connecting the two pistons 5, 11. When either the spool valve 13 is closed or the trigger 6 is released the rear part of the barrel 1 vents the air thus removing the driving force pushing the front piston 5 via the connecting rod 12.

Thus in order to expel the sealant both the trigger 6 and the spool valve 13 must be actuated. This provides a safety feature preventing the inadvertent expulsion of sealant which can be harmful especially if accidentally inhaled or injected into the eyes.

The trigger valve air line 9 continues all the way to the pressure regulator 10 at the back of the gun 1. From here the air passes through the regulator 10 and into the spool valve 13.

In use the barrel 2 of the gun 1 has a threaded forward opening 3 formed on the outer wall of a cartridge receiving tube 20 connected to a forward end of the barrel 2 and into which tube 20 the cartridge 4 is in use inserted. In use a nozzle 21 is then inserted through the opening 3 and has flanged walls 22 which form a close fit with the inner wall of the receiving tube 20. The nozzle 21 has an aperture formed in part with internal threads 23. Finally a front ring 24 to hold the nozzle 21 in is screwed via an internally threaded collar to an externally threaded end of the tube 20 to engage with the forward one of the flanges 22.

:.". The cartridge 4 itself is a collapsible thin walled plastics container in the form of a bulb and * . contains a suitable settable liquid sealant which may be an anaerobic sealant. In use the r": cartridge 4 is attached by an externally threaded neck 25 to the internally threaded neck 23 of the nozzle 21 before insertion into the gun 1. The cartridge and nozzle assembly are then : ... inserted through the opening 3 in the gun 1 until the cartridge seats against the front piston 5. The cartridge has a rounded bottom which after insertion seats on a concave surface 20 of the forward piston 5. When air pressure is applied and the front piston 5 moves it squeezes thécartridge 4 against an internal conical wall 26 of the nozzle 21 and sealant is : ejected from the cartridge 4 and thence out through the nozzle aperture 23 to the joint. In order to maintain the cartridge and nozzle in position within the gun 1 after insertion the front ring 24 is screwed via the collar to the threaded end of the tube 20.

After the sealant has been ejected the two pistons 4 and 10 are returned to their initial positions and this is done manually. Once the sealant has been ejected into the joint the front ring 19 on the gun 1 holding the nozzle 14 in place is removed by being unscrewed from the tube 16. The nozzle 14 will then pulled out of the tube 16 with the spent sealant cartridge attached. Once the spent cartridge is removed the tube 16 can be removed from the remainder of the gun as the tube 20 is externally threaded..and..isscrewed to an internally threaded front portion 23 of the rest of the gun 1. The tube 20is unscrewed from the rest of the gun 1 and pulled off from or over the front piston 5. The piston 5 can now be manually pushed back to its initial position and the tube 20 refitted: Referring to the handle and trigger, the handle 6 comprises a hollow body into which extends part of the air line or tube 8. The tube part 8 passes through an aperture In the base of the handle 7 and is locked in position by a nut which is attached to an externally threaded inlet at the base of the handle 7 through which inlet the tubes passes.. The tube 8 terminates in a valve 26 located within the handle 7. Extending from the valve 26 is the further line or tube 9 which extends through an aperture in the body of the handle and then extends rearwardly to terminate in the pressure regulator 10.

The trigger 6 is of conventional design comprising an elongate component shaped for gripping manually and hingably connected to the handle so that the trigger can be actuated and released. The rear of the trigger 6 has a small button/pin extension 27 which when the trigger 6 is pressed to actuate it presses against a similar protrusion in the form of a button/pin extension 28 on the body of the air valve 26. while not shown this is actually a small plunger operating a spring loaded valve inside the body of this valve 26. So to actuate the device the user holds the handle 7 and squeezes the trigger 6. This allows air to pass via the tube 9 to the pressure regulator 10 at the back of the gun 1, but this air will only get into the rear driving cylinder/barrel 2 if the safety button in the spool valve 13 is also held down.

A standard sealant delivery tube (not shown) is provided. This type of tube is used with hand powered guns. The delivery tube connects to the standard injection nipple that has been screwed into a threaded hole in the gas main joint to be injected. S. so * * 5 * S

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Claims

Claims 1. A sealant injection gun comprising a barrel to receive air under pressure, the barrel having a forward end with an opening to receive a cartridge or container of sealant to form an air tight seal with the wall of the barrel, a piston for engaging with the cartridge or container on forward movement of the piston to eject the sealant from the opening into a joint, a trigger permitting the injection of air into the barrel when the trigger is actuated so as to permit the air pressure to move the piston and preventing the injection of air into the barrel when the trigger is released, the trigger having means for connecting an air line to the trigger.
2. A sealant injection gun comprising a barrel to receive a fluid under pressure1 the barrel having a forward end with an opening to receive a cartridge or container of sealant to form an air tight seal with the wall of the barrel, a piston for engaging with the cartridge or container on forward movement of the piston to eject the sealant from the opening into a joint, a trigger permitting the injection of the fluid into the barrel when the trigger is actuated. so.asto permit the fluid pressure to move the piston and prevent the injection of fluid into the barrel when the trigger is released, the trigger having means for connecting a fluid line to the trigger and a valve adapted to control the flow of fluid to the piston, the valve being-biased to.close..to prevent the flow of fluid to the piston but operable manually against the bias to open and permit the flow of fluid to the piston but only when the trigger :.". has been actuated. * .
3. A sealant injection gun as claimed in claim 2 in which the fluid is air and the fluid line is an air line. * * . * ***
4. A sealant injection gun as claimed in claim 2 or claim 3 in which there is a further piston rearward-of the other piston and connectedto the other piston by a rod, the fluid-line terminating behind the further piston to cause the fluid pressure to move the further piston : and thereby the other piston to eject the sealant. **
5. A sealant injection gun as claimed in any of claims 2 to 4 in which the trigger has a hollow body through which extends a fluid line which terminates behind the further piston, there being means within the trigger to connect and disconnect the fluid line to and from the further piston on movement of a handle with which the trigger is provided to actuate and release the trigger.
6. A sealant injection gun as claimed in any of claims 2 to 5 in which the valve is a spool valve.
7. A sealant injection gun substantially as hereinbefore described with reference to the drawing.