GB2063941A - Impregnating a porous component with settable sealant - Google Patents

Abstract

A settable sealant, e.g. an anaerobic resin, is introduced via pipe (17) and aperture (16) into a chamber defined between a component (31), such as an i.c. engine cylinder block or a pump housing and a component support structure (13) whilst air is vented from the chamber through an opening. The opening is closed after the chamber has been filled with sealant and the sealant is pressurised in the chamber. The impregnated sealant is then allowed or caused to cure. Preferably, the sealant is introduced into the chamber and pressurized therein by gas pressure from inlet (18). <IMAGE>

Description

SPECIFICATION A method of and apparatus for impregnating a porous component with suitable sealant The invention relates to a method of and apparatus for impregnating a porous component, particularly but not exclusively a porous metal casting, with a settable sealant.

It is known to impregnate porous metal castings, which are intended to contain a fluid, e.g.

i-c engine cylinder blocks and pump housings, with a sealant such as an anaerobic resin to render them pressure tight. In a known method a plurality of components are loaded into a vacuum chamber in baskets. A vacuum is then created in the vacuum chamber before flooding with anaerobic resin. However, apparatus employed for performing this method is bulky, requires high capital outlay and has high running costs associated with it.

The invention provides in one aspect a method of impregnating a porous component with a sealant, the method comprising: (a) introducing settable sealant into a chamber -defined between the component and a component support structure whilst allowing air to vent from the chamber through an opening, (b) closing the opening after the chamber has been filled with sealant and pressurising the sealant in the chamber to force the sealant into the pores in that part of the component in contact with the sealant, (c) allowing or causing the impregnated sealant to cure at the pore surfaces.

Preferably, after step (b) has been completed the excess sealant in the chamber is returned to a reservoir thereof.

Preferably, the sealant is an anaerobic resin, and step (c) includes immersing the component in an activator to cure the sealant at the pore surfaces. Alternatively the sealant may be a thermosetting resin, and step (c) includes immersing the component in a liquid at an elevated temperature.

It may be advantageous to wash the component between steps (b) and (c). A final wash after step (c) may also be advantageous.

Preferably, gas pressure is utilized to feed the sealant into the chamber in the component and to pressurize the sealant therein.

Preferably, the sealant is introduced into the chamber at the lower end of the chamber and air is vented from the upper end of the chamber.

The invention provides in another aspect apparatus for performing the above method, the apparatus comprising a component support structure which includes a seal and which is so constructed and arranged that when in use a porous component is engaged with the seal a chamber is defined between the component and the component support structure, first means for releasably engaging the component with the seal, and second means for introducing a settable sealant into the chamber and for applying pressure to the sealant in the chamber.

Preferably, the porous components to be impregnated may be of a kind having a chamber and at least two openings which communicate the chamber with the exterior of the component in which case, preferably the component support structure comprises a component receiving deck having an opening therein through which the sealant can be introduced, and the seal comprises a layer of resilient sealing material on the deck and with which the component may be engaged such that one of the openings in the component communicates with the opening in the deck, the other opening serving to vent air from the chamber as it is filled with sealant.

Preferably, the first means comprises releasable clamping means which may advantageously include fluid pressure operated means.

Preferably, the second means comprises a reservoir for sealant, the reservoir having an outlet which communicates with the lower end of the reservoir and through which sealant is in use, introduced into the chamber, and a gas inlet which communicates with the upper end of the reservoir and which is above the, in use, upper level of material in the reservoir, so that, in use the sealant can be introduced into the chamber and pressurised therein by gas pressure applied to said gas inlet.

Preferably, the apparatus further comprises a tank for receiving an activator in a case where the sealant is an anaerobic resin, or a liquid at an elevated temperature in a case where the sealant is a thermosetting resin.

Advantageously, means are provided for transporting a component after impregnation to the tank.

The apparatus may also comprise a wash station at which the component may be washed after impregnation and before immersing in the activator medium and a rinse station at which the component may be rinsed after removal from the activator medium.

The invention also provides a porous component impregnated according to the above method.

Preferably, the component is a metal casting and the material with which it is impregnated is an anaerobic resin.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of one embodiment of impregnating apparatus according to the invention, and Figure 2 is a section aiong line Il-Il of Figure 1.

Referring to the drawings, the apparatus shown therein comprises an elevated, elongate deck 10 supported by suitable side and end panels 11 and 12 respectively. The deck 10 comprises a rigid metal support layer 1 3 and a layer 14 of resilient sealing material, such as rubber, secured to the upper surface of layer 13. A right cylindrical reservoir 1 5 is secured to the underside of the deck 10 at one longitudinal end thereof. The deck 10 has therein an aperture 1 6 which is coaxial with the reservoir 15 and which communicates with a pipe 17 which extends downwardly into the reservoir 1 5 and which terminates just short of the lower end thereof. The reservoir has an air inlet 18 and a closable vent 1 9 (see Figure 2) adjacent to its upper end.

A bridge-like support 20 having upstanding legs 21 and 22 and a cross-member 23 is secured to opposite longitudinal sides of the deck 10 so that the cross-member extends directly above and is intersected by the axis of the reservoir 1 5. The cross-member carries two pneumatically operated clamping devices 24 and 25 (see Figure 2).

The apparatus also comprises a wash tray 26 and two tanks 27 and 28 (see Figure 1) which are spaced apart longitudinally of the deck 10. The tray 26 and each tank is open at its upper end which is coplanar with the deck 10. A sling conveyor 29 extends longitudinally of the deck 10 and is secured at one end to the cross-member 23 midway between the ends of the latter and at its other end to an upstanding leg 30 which is secured to the other end of the deck 10, viz that end of the deck 10 remote from the reservoir 15.

The apparatus is intended for use in impregnating porous components particularly porous metal castings such as i-c engine cylinder blocks and pump housings, with a settable sealant such as a low viscosity anaerobic resin, viz a resin which will set in the absence of oxygen, or a thermosetting resin. Such components should have a chamber and at least two openings which communicate the chamber with the exterior of the component.

The resin is contained in reservoir 15 and may be aerated to keep it activated.

A component, designated by the reference numberal 31 (see Figure 2), is clamped to the deck 10 by the clamping devices 24 and 25 with a lower opening in the component 31 communicating with the aperture 1 6 in the deck.

All other openings in the component and communicating with the chamber therein are blanked off such as by plugs with the exception of the uppermost opening. Air, or any other suitable gas, is fed into the reservoir through the inlet 18, vent 19 being closed. The air forces the resin into the chamber in the component 31 through pipe 17 and air is vented from the chamber through the uppermost opening in the component. When the chamber is full of resin, the uppermost opening in the component is blanked off and the resin in the component is pressurised by the pressurised air entering through the inlet 1 8. The pressure of the air and the duration of the pressurisation will be determined according to the wall thickness and the type of porosity of the component. During pressurisation the walls of the chamber are impregnated with resin.Thereafter, the air pressure is reduced to zero and the uppermost opening in the component 31 and the vent 19 are opened. Excess resin returns to the reservoir 1 5 and the clamping devices 24 and 25 are released.

The component 31 is then transported by the sling conveyor to tray 26 where it is flushed through with water. It is then immersed in an activator, e.g. ascorbic acid or a liquid at an elevated temperature depending on whether the resin is an anaerobic or a thermosetting resin respectively. The activator or liquid as the case may be is contained in tank 27. The component is then transported to tank 28 where it is given a final rinse to remove the activator or liquid, accelerate the cure of the resin and provide corrosion protection.

The apparatus may be automatically controlled or may be controlled manually.

If the components to be impregnated are of a kind which do not have a chamber, the walls of which are to be impregnated, but have for example a flat or substantially flat surface which is to be impregnated, the deck 10 may be provided with an annulus sealingly secured thereto or integral therewith. A sealing ring such as an 'O'ring can be mounted on the upper edge of the annulus and the surface of the component can be releasably engaged with the sealing ring so that a chamber is defined between the deck 10, the annulus and the component.

Claims (20)

1. A method of impregnating a porous component with a sealant, the method comprising: (a) introducing settable sealant into a chamber defined between the component and a component support structure whilst allowing air to vent from the chamber through an opening, (b) closing the opening after the chamber has been filled with sealant and pressurising the sealant in the chamber to force the sealant into the pores in that part of the component in contact with the sealant, (c) allowing or causing the impregnated sealant to cure at the pore surfaces.

2. The method of claim 1, wherein after step (b) has been completed the excess sealant in the chamber is returned to a reservoir thereof.

3. The method of claim 1 or claim 2, wherein the sealant is an anaerobic resin and step (c) includes immersing the component in an activator to cure the sealant at the pore surfaces.

4. The method of claim 1 or claim 2, wherein the sealant is a thermosetting resin and step (c) includes immersing the component in a liquid at an elevated temperature.

5. The method of any one of the preceding claims, wherein the component is washed between steps (b) and (c).

6. The method of any one of the preceding claims, wherein the component is washed after step (c).

7. The method of any one of the preceding claims, wherein gas pressure is utilised to feed the sealant into the chamber in the component and to pressurise the sealant therein.

8. The method of any one of the preceding claims, wherein the sealant is introduced into the chamber at the lower end of the chamber and air is vented from the upper end of the chamber.

9. A method of impregnating a porous component with a sealant, substantially as hereinbefore described with reference to the accompanying drawings.

10. Apparatus for performing the method of claim 1 , the apparatus comprising a component support structure which includes a seal and which is so constructed and arranged that when in use a porous component is engaged with the seal a chamber is defined between the component and the component support structure, first means for releasably engaging the component with the seal, and second means for introducing a settable sealant into the chamber and for applying pressure to the sealant into the chamber.

11. The apparatus of claim 10, wherein the porous components are of a kind having a chamber and at least two openings which communicate the chamber with the exterior of the component and the component support structure comprises a component receiving deck having an opening therein through which the sealant can be introduced, and the seal comprises a layer of resilient sealing material on the deck and with which the component may be engaged such that one of the openings in the component communicates with the opening in the deck, the other opening serving to vent air from the chamber as it is filled with sealant.

12. The apparatus of claim 10 or claim 11, wherein the first means comprises releasable clamping means including fluid pressure operated means.

13. The apparatus of any one of claims 10-12, wherein the second means comprises a reservoir for sealant, the reservoir having an outlet which communicates with the lower end of the reservoir and through which sealant is, in use, introduced into the chamber, and a gas inlet which communicates with the upper end of the reservoir and which is above the, in use, upper level of material in the reservoir, so that, in use the sealant can be introduced into the chamber and pressurised therein by gas pressure applied to said gas inlet.

14. The apparatus of any one of claims 10-13, further comprising a tank for receiving an activator in a case where the sealant is an anaerobic resin, or a liquid at an elevated temperature in a case where the sealant is a thermosetting resin.

1 5. The apparatus of claim 14, wherein means are provided for transporting a component after impregnation to the tank.

16. The apparatus of claim 14 or claim 15, wherein the tank is for receiving an activator and wherein there is provided a wash station at which the component may be washed after impregnation and before immersing in the activator medium and a rinse station at which the component may be rinsed after removal from the activator medium.

17. Apparatus for impregnating a porous component with a sealant, substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.

18. A porous component impregnated by the method set forth in any one of claims 1-9.

19. The component of claim 18 and being a metal casting.

20. The component of claim 19, impregnated with an anaerobic resin.