GB2179403A

GB2179403A - Sealant delivery system

Info

Publication number: GB2179403A
Application number: GB08619643A
Authority: GB
Inventors: John Robert George Clark
Original assignee: ALH Systems Ltd
Current assignee: ALH Systems Ltd
Priority date: 1985-08-12
Filing date: 1986-08-12
Publication date: 1987-03-04
Also published as: GB8619643D0; GB8520217D0

Abstract

A sealant delivery system has a reservoir (7) for air or other oxygen- containing gas, which is connected to a vessel (1) containing an anaerobic sealant (10). When the air is passed through valve (6) to a pipe (9) extending into the sealant (10), curing of the sealant (10) is inhibited, by the action of the air passing through the sealant (10). Furthermore, the air establishes a top-pressure in the vessel (1), forcing the sealant (10) from the outlet (2) and through a conduit (3) to an object to be sealed. In this way, curing of the sealant (10) before it reaches the object may be prevented. <IMAGE>

Description

SPECIFICATION Sealant delivery system The present invention relates to a sealant delivery system, suitable for delivering sealant for sealing leaks in metal components such as castings, vessels, and pipe joints.

It is known to use anaerobic liquids as the sealant. Such liquids have the property of curing in the presence of metals and the absence of oxygen. For sealing non-metallic components, it is usual to add a metal catalyst to initiate curing, and this catalyst ensures that the curing is uniform and the ultimate seal has predictable characteristics.

When sealing joints in non-metallic pipes, for example, the sealant is mixed with the catalyst, and poured into a vessel which has an outlet at the bottom thereof connected via conduit to the pipe joint to be sealed. A top pressure is created within the vessel and this forces the sealant through the conduit and into the pipe joint. However, it has been found that, particularly in hot weather, the sealant cures before it has been expelled fully from the vessel, thereby preventing an efficient seal being achieved, and damaging the delivery system.

The present invention seeks to solve this problem by making use of the fact that curing is inhibited by oxygen. Whilst the sealant is in the vessel, oxygen containing gas (e.g. air) is bubbled through the sealant and this prevents it from curing. Therefore the possibility of curing within the vessel itself is eliminated, and so the sealant can always be expelled from the vessel into the object, e.g. pipe joint to be sealed before curing occurs. Preferably the oxygen-containing gas, which is used to inhibit curing, is also that which creates the top-pressure within the vessel.

An embodiment of the invention will now be described in detail, by way of example, with reference to the accompanying drawing in which the sole Figure shows an embodiment of a sealant delivery system according to the present invention.

Referring to the Figure, a sealant vessel 1 has an outlet 2 adjacent its lower end, from which extends a conduit 3 which is inserted in the object to be sealed (e.g. a pipe joint). The inlet 4 to the vessel 1 is at the upper end, and this- connects to a pipe 5 containing a pressure regulator 6 leading to an air reservoir 7. The inlet pipe 8 to the air reservoir 7 is connected to a pump, e.g. a foot-pump, which enables the air within the reservoir 7 to be pressurised.

As can be seen, a pipe 9 extends downwardly within the vessel 1 from its inlet 4, to a point adjacent its lower end.

In operation, sealant is mixed with a catalyst and poured into the vessel 1 (the sealant being indicated at 10 in the Figure). The air in the reservoir 7 is pressurised, using a pump, and the pressure regulator 6 controlled to permit the pressurised air to pass from the reservoir to the vessel. The pressurised air emerges from the pipe 9 within the sealant 10, and bubbles through it to the top of the vessel 1, establishing an air pocket 11. As the pressure in the air pocket 11 builds up, as more enters the vessel 1 from the reservoir 7, the sealant 10 is forced out through the conduit 3 to the object to be sealed. The oxygen in the air bubbling through the sealant 10, from the pipe 9, inhibits curing of the sealant 10, so preventing its solidification within the vessel 1. In this way, the efficiency of the sealing operation is promoted.

Once the required amount of sealant 10 has been expelled from the vessel 1, the vessel 1 needs to be depressurised. This is achieved by a vent in the pressure regulator 6, which permits the air in pocket 11 to be vented directly to the atmosphere. To prevent any remaining sealant being forced up the pipe 9 to the valve 6 during depressurisation, there is a one-way valve 12 adjacent the inlet 4 of the vessel 1. This permits the air to escape directly from the pocket 11 to the pipe 5.

It is not necessary to use the air-reservoir system described above. The vessel 1 may be connected directly to a compressed air tank, so that operation of the valve 6, merely reduces the pressure in the tank. However, with such a system there is the risk that the system may be left running for too long, so that the vessel 1 is completely emptied of sealant 10, and air is forced through the conduit 3 into the article to be sealed. This may damage the seal. The use of a relatively low-pressure air reservoir prevents this from occurring.

Since it is oxygen that inhibits curing of the sealant 10, the gas fed into the vessel 1 could be pure oxygen. However, it has been found that the amount of oxygen in the air is sufficient to inhibit curing completely, and so other arrangements (which will be more expensive) are unnecessary.

1. A sealant delivery system having a vessel containing sealant and means for injecting oxygen-containing gas into the sealant in the vessel, thereby to inhibit curing of the sealant.

2. A system according to claim 1, wherein the vessel is closed except for a sealant outlet and an inlet for the gas, whereby the gas establishes a pressure in the vessel to expel the sealant from the outlet.

3. A system according to claim 2, wherein the inlet for the gas is connected to a gas reservoir, and there is a vent in the inlet for permitting gas in the vessel to return to the reservoir.

4. A system according to any one of claims 1 to 3, wherein the gas is air.

5. A system according to any one of the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sealant delivery system The present invention relates to a sealant delivery system, suitable for delivering sealant for sealing leaks in metal components such as castings, vessels, and pipe joints. It is known to use anaerobic liquids as the sealant. Such liquids have the property of curing in the presence of metals and the absence of oxygen. For sealing non-metallic components, it is usual to add a metal catalyst to initiate curing, and this catalyst ensures that the curing is uniform and the ultimate seal has predictable characteristics. When sealing joints in non-metallic pipes, for example, the sealant is mixed with the catalyst, and poured into a vessel which has an outlet at the bottom thereof connected via conduit to the pipe joint to be sealed. A top pressure is created within the vessel and this forces the sealant through the conduit and into the pipe joint. However, it has been found that, particularly in hot weather, the sealant cures before it has been expelled fully from the vessel, thereby preventing an efficient seal being achieved, and damaging the delivery system. The present invention seeks to solve this problem by making use of the fact that curing is inhibited by oxygen. Whilst the sealant is in the vessel, oxygen containing gas (e.g. air) is bubbled through the sealant and this prevents it from curing. Therefore the possibility of curing within the vessel itself is eliminated, and so the sealant can always be expelled from the vessel into the object, e.g. pipe joint to be sealed before curing occurs. Preferably the oxygen-containing gas, which is used to inhibit curing, is also that which creates the top-pressure within the vessel. An embodiment of the invention will now be described in detail, by way of example, with reference to the accompanying drawing in which the sole Figure shows an embodiment of a sealant delivery system according to the present invention. Referring to the Figure, a sealant vessel 1 has an outlet 2 adjacent its lower end, from which extends a conduit 3 which is inserted in the object to be sealed (e.g. a pipe joint). The inlet 4 to the vessel 1 is at the upper end, and this- connects to a pipe 5 containing a pressure regulator 6 leading to an air reservoir 7. The inlet pipe 8 to the air reservoir 7 is connected to a pump, e.g. a foot-pump, which enables the air within the reservoir 7 to be pressurised. As can be seen, a pipe 9 extends downwardly within the vessel 1 from its inlet 4, to a point adjacent its lower end. In operation, sealant is mixed with a catalyst and poured into the vessel 1 (the sealant being indicated at 10 in the Figure). The air in the reservoir 7 is pressurised, using a pump, and the pressure regulator 6 controlled to permit the pressurised air to pass from the reservoir to the vessel. The pressurised air emerges from the pipe 9 within the sealant 10, and bubbles through it to the top of the vessel 1, establishing an air pocket 11. As the pressure in the air pocket 11 builds up, as more enters the vessel 1 from the reservoir 7, the sealant 10 is forced out through the conduit 3 to the object to be sealed. The oxygen in the air bubbling through the sealant 10, from the pipe 9, inhibits curing of the sealant 10, so preventing its solidification within the vessel 1. In this way, the efficiency of the sealing operation is promoted. Once the required amount of sealant 10 has been expelled from the vessel 1, the vessel 1 needs to be depressurised. This is achieved by a vent in the pressure regulator 6, which permits the air in pocket 11 to be vented directly to the atmosphere. To prevent any remaining sealant being forced up the pipe 9 to the valve 6 during depressurisation, there is a one-way valve 12 adjacent the inlet 4 of the vessel 1. This permits the air to escape directly from the pocket 11 to the pipe 5. It is not necessary to use the air-reservoir system described above. The vessel 1 may be connected directly to a compressed air tank, so that operation of the valve 6, merely reduces the pressure in the tank. However, with such a system there is the risk that the system may be left running for too long, so that the vessel 1 is completely emptied of sealant 10, and air is forced through the conduit 3 into the article to be sealed. This may damage the seal. The use of a relatively low-pressure air reservoir prevents this from occurring. Since it is oxygen that inhibits curing of the sealant 10, the gas fed into the vessel 1 could be pure oxygen. However, it has been found that the amount of oxygen in the air is sufficient to inhibit curing completely, and so other arrangements (which will be more expensive) are unnecessary. CLAIMS

4. A system according to any one of claims 1 to 3, wherein the gas is air.

5. A system according to any one of the preceding claims, wherein the sealant is an aerobic sealant containing a metal catalyst.

6. A sealant delivery system substantially as herein described with reference to and as illustrated in the accompanying drawing.

7. A method of sealing components comprising injecting sealant from a sealant delivery system according to any one of the preceding claims into the components.