GB1562283A

GB1562283A - Leak testing apparatus

Info

Publication number: GB1562283A
Application number: GB3358575A
Authority: GB
Original assignee: PERMAT MACHINES Ltd
Current assignee: PERMAT MACHINES Ltd
Priority date: 1976-11-10
Filing date: 1976-11-10
Publication date: 1980-03-12

Description

(54) LEAK TESTING APPARATUS (71) We, PERMAT MACHINES LIMITED (formerly PERFECTION MACHINES AND TOOLS LIMITED), a British Company of Station Road, Coleshill, Birmingham B46 1JG, 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 apparatus for testing components for leaks. Such apparatus is known and works on the principle that the component to be tested is internally pressurised with air or other gas and immersed in a liquid, the internal pressure of the component being greater than the external pressure exerted by the liquid on the component so that, if there is a leak, then the air or gas will bubble up through the liquid indicating not only the existence of the leak but also its location.

The invention will be described in relation to apparatus for testing the cylinder head of an internal combustion engine for leakage. The invention, however, is not limited to apparatus for testing such heads but can be used for testing any hollow component which can be pressurised.

It is known either to lower the pressurised component into a bath of liquid or to cause the level of liquid to rise up within a bath and cover the pressurised component without moving the latter. The invention is concerned with apparatus of this latter type in which the component remains stationary in a first container and the liquid, normally water, is held in a second container and is caused to enter the first container and cover the stationary component. Such apparatus is hereinafter referred to as "apparatus of the type specified." Heretofore, the movement of liquid, hereinafter referred to for convenience as water, to cover the component has been effected either by means of a displacement cylinder or by means of one or more pumps.

The object of the present invention is to provide apparatus in which the water can be moved rapidly to submerge and uncover the component in a simpler and less expensive manner than heretofore.

According to the invention we provide apparatus of the type specified for testing components for leakage and which comprises a first tank to receive the component to be tested, a second storage tank to contain liquid to submerge the component in the first tank for testing, the second tank being fixed in position in relation to the first tank, a conduit between the tanks and means whereby pneumatic pressure may be applied to, and vented from, the second tank to transfer liquid from the second tank via the conduit to the first tank and to allow liquid to pass from the first tank via the conduit to the second tank by gravity respectively.

In operation of the apparatus, the component to be tested is placed in the first tank and is pressurised, at this time the first tank is empty of liquid. The second tank is then pressurised to transfer liquid from the second tank to the first tank thus to submerge the component. The component is then inspected to see if there is any leakage and if so from where. Once the component has been inspected, the pressure is vented from the second tank and the liquid returns to the second tank by gravity thus uncovering the component.

The second tank can be pressurised from the compressed air line which is normally found in factories and for a component of the size of a cylinder head, for example, the transfer of liquid from the second tank to the first tank may take only a second.

It will be seen that apparatus embodying the invention is particularly useful for testing components which are being mass produced such as automobile components as cylinder heads, manifolds, carburettors, gear boxes and differential casings although the invention is applicable to the leak testing of other components.

Normally, the first tank will be opentopped so that the component may easily be placed in the tank and removed therefrom. Alternatively the first tank may have a side opening for this purpose and closure means such as a door for closing the opening, sealing means being provided to prevent liquid escaping from the tank through the opening when the closure member is in its operative position. There will be means provided for plugging the apertures in the component and applying pneumatic pressure. The means for plugging the apertures will of course vary in design depending on the component to be tested.

In a preferred arrangement, the first tank is supported directly above the second tank.

The tanks may have the same shape in plan view. In this arrangement, the conduit can project directly from the base of the first tank into the second tank towards the bottom thereof.

When the first tank is above the second tank the means for venting pneumatic pressure from the second tank may comprise a vent pipe which extends upwardly from the second tank through the first tank to a position above the liquid level therein when the component is bein gtested, said pipe includes a vent valve which when open releases the pneumatic pressure from the second tank.

The vent valve will be as large as conveniently possible to enable rapid uncovering of the component after it has been tested.

It is possible to have either separate means for pressurising and venting the second tank or a single means which may be used both for pressurising and venting the second tank.

The invention will now be described in detail by way of example with reference to the accompanying drawing which is a crosssection through apparatus for testing a cylinder head for leakage.

Referring now to the drawing, there is a first tank indicated generally at 10 and, immediately below the first tank, a second tank indicated at 11. The tanks are rectangular in plan view and have two common side walls 12 and 13 which, at their lower ends, are welded to a base plate 14. The lower wall of the second tank is provided by a plate 15 welded between the walls 12 and 13 and the opposite end walls and this is supported by gussets 16. The bottom of the first tank is formed by a plate 17 which is again welded between the walls 12 and 13 and the opposite end walls and the plate 17 has a central aperture 18 therein. A pipe or conduit 19 extends downwardly from the plate 17 towards the plate 15.

The component to be tested, in the present instance a cylinder head, is indicated at 20. The apertures in the component are closed by means of plugs, some of which are indicated at 21 and which are carried by a fixture indicated generally at 22. The fixture does not form part of the present invention and will be designed to carry plugs in the appropriate locations for the components to be tested.

A vent pipe 23 extends upwardly from the second tank 11, the lower end of the vent pipe being indicated at 24 and being below the plate 17. At the upper end of the vent pipe is provided a vent valve 25.

A connection 26 is provided whereby compressed air can be supplied to the tank 11.

When there is no liquid in the tank 10, the liquid level in the tank 11 is indicated by the line 27. If it is now desired to transfer liquid from the tank 11 to the tank 10, the vent valve 25 is closed and compressed air is applied to the connection 26.

This forces the liquid up through the conduit 19 so that liquid enters the first tank 10 to a level indicated at 28 which submerges the component. The liquid level in the second tank drops to the level 29. Means is provided for cutting off the supply of compressed air when the desired liquid level has been obtained in the tank 10. This may be done either automatically or manually.

The fixture is arranged so that the interior of the cylinder head 20 can be pressurised and once the cylinder head is submerged, any leak will be apparent and the location of the leak can be marked. Thereafter, the liquid in the tank 10 can be returned to the tank 11 by opening the vent valve 25 thus allowing air to pass up the vent pipe 23. The liquid in the first tank 10 will then return by gravity through the conduit 19 into the second tank 11.

The displacement of liquid between the tanks 10 and 11 is extremely rapid, more rapid than when using a pump to transfer the liquid. Moreover, the apparatus is cheaper than one employing a pump.

Although the invention has been described in relation to apparatus having two separate means for pressurising and venting the tank l lit may be convenient to have a single means which can act both to allow air to enter the tank 11 and to vent from the tank. Thus the valve 25 could be a dual purpose Valve instead of merely a vent valve.

It will be seen that the invention provides a simple apparatus whereby components can be leak tested.

WHAT WE CLAIM IS: 1. Apparatus of the type specified for testing components for leakage and which comprises a first tank to receive the com

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. cylinder heads, manifolds, carburettors, gear boxes and differential casings although the invention is applicable to the leak testing of other components. Normally, the first tank will be opentopped so that the component may easily be placed in the tank and removed therefrom. Alternatively the first tank may have a side opening for this purpose and closure means such as a door for closing the opening, sealing means being provided to prevent liquid escaping from the tank through the opening when the closure member is in its operative position. There will be means provided for plugging the apertures in the component and applying pneumatic pressure. The means for plugging the apertures will of course vary in design depending on the component to be tested. In a preferred arrangement, the first tank is supported directly above the second tank. The tanks may have the same shape in plan view. In this arrangement, the conduit can project directly from the base of the first tank into the second tank towards the bottom thereof. When the first tank is above the second tank the means for venting pneumatic pressure from the second tank may comprise a vent pipe which extends upwardly from the second tank through the first tank to a position above the liquid level therein when the component is bein gtested, said pipe includes a vent valve which when open releases the pneumatic pressure from the second tank. The vent valve will be as large as conveniently possible to enable rapid uncovering of the component after it has been tested. It is possible to have either separate means for pressurising and venting the second tank or a single means which may be used both for pressurising and venting the second tank. The invention will now be described in detail by way of example with reference to the accompanying drawing which is a crosssection through apparatus for testing a cylinder head for leakage. Referring now to the drawing, there is a first tank indicated generally at 10 and, immediately below the first tank, a second tank indicated at 11. The tanks are rectangular in plan view and have two common side walls 12 and 13 which, at their lower ends, are welded to a base plate 14. The lower wall of the second tank is provided by a plate 15 welded between the walls 12 and 13 and the opposite end walls and this is supported by gussets 16. The bottom of the first tank is formed by a plate 17 which is again welded between the walls 12 and 13 and the opposite end walls and the plate 17 has a central aperture 18 therein. A pipe or conduit 19 extends downwardly from the plate 17 towards the plate 15. The component to be tested, in the present instance a cylinder head, is indicated at 20. The apertures in the component are closed by means of plugs, some of which are indicated at 21 and which are carried by a fixture indicated generally at 22. The fixture does not form part of the present invention and will be designed to carry plugs in the appropriate locations for the components to be tested. A vent pipe 23 extends upwardly from the second tank 11, the lower end of the vent pipe being indicated at 24 and being below the plate 17. At the upper end of the vent pipe is provided a vent valve 25. A connection 26 is provided whereby compressed air can be supplied to the tank 11. When there is no liquid in the tank 10, the liquid level in the tank 11 is indicated by the line 27. If it is now desired to transfer liquid from the tank 11 to the tank 10, the vent valve 25 is closed and compressed air is applied to the connection 26. This forces the liquid up through the conduit 19 so that liquid enters the first tank 10 to a level indicated at 28 which submerges the component. The liquid level in the second tank drops to the level 29. Means is provided for cutting off the supply of compressed air when the desired liquid level has been obtained in the tank 10. This may be done either automatically or manually. The fixture is arranged so that the interior of the cylinder head 20 can be pressurised and once the cylinder head is submerged, any leak will be apparent and the location of the leak can be marked. Thereafter, the liquid in the tank 10 can be returned to the tank 11 by opening the vent valve 25 thus allowing air to pass up the vent pipe 23. The liquid in the first tank 10 will then return by gravity through the conduit 19 into the second tank 11. The displacement of liquid between the tanks 10 and 11 is extremely rapid, more rapid than when using a pump to transfer the liquid. Moreover, the apparatus is cheaper than one employing a pump. Although the invention has been described in relation to apparatus having two separate means for pressurising and venting the tank l lit may be convenient to have a single means which can act both to allow air to enter the tank 11 and to vent from the tank. Thus the valve 25 could be a dual purpose Valve instead of merely a vent valve. It will be seen that the invention provides a simple apparatus whereby components can be leak tested. WHAT WE CLAIM IS:

1. Apparatus of the type specified for testing components for leakage and which comprises a first tank to receive the com

ponent to be tested, a second storage tank to contain liquid to submerge the component in the first tank for testing the second tank being fixed in position in relation to the first tank, a conduit between the tanks and means whereby pneumatic pressure may be applied to, and vented from, the second tank to transfer liquid from the second tank via the conduit to the first tank and to allow liquid to pass from the first tank via the conduit to the second tank by gravity respectively.

2. Apparatus according to claim 1 in which the first tank is open-topped so that the component may be easily placed in and removed therefrom.

3. Apparatus according to claim 1 in which the first tank has a side opening for the introduction and removal of the component, a closure means for closing the opening and sealing means to prevent liquid escaping from the tank through the opening when the closure means is in its operative position.

4. Apparatus according to any one of claims 1 to 3 in which the first tank is supported directly above the second tank.

5. Apparatus according to claim 4 in which the conduit projects directly from the base of the first tank into the second tank towards the bottom thereof.

6. Apparatus according to claim 4 or claim 5 in which the means for venting pneumatic pressure from the second tank comprises a vent pipe which extends upwardly from the second tank through the first tank to a position above the liquid level therein when the component is being tested, said pipe includes a vent valve which when open releases the pneumatic pressure from the second tank.

7. Apparatus according to any one of claims 1 to 6 in which the means for venting the second tank is also used as the means for pressurising the tank.

8. Apparatus for testing components for leakage, said apparatus being constructed and arranged substantially as hereinbefore defined with reference to and as shown in the accompanying drawing.