GB2149126A

GB2149126A - Pressure testing components

Info

Publication number: GB2149126A
Application number: GB08423280A
Authority: GB
Inventors: Michael Brian Brotherton
Original assignee: Brotherton & Thomas
Current assignee: Brotherton & Thomas
Priority date: 1983-10-27
Filing date: 1984-09-14
Publication date: 1985-06-05
Also published as: GB8423280D0; GB2149126B

Abstract

A method and apparatus for pressure testing a shell-like component C utilises an elastic sleeve 11 positioned within the component and inflated by means of hydraulic fluid. The sleeve extends between opposed end caps 13, 10 and an initial stage of the inflation ensures sealing between the ends of the sleeve and the end caps. The upper end cap 13 may be carried by an upper mandrel part 15 slidable in a cylinder 17 within a lower mandrel part which passes through the lower end cap 10. The mandrel parts may thus be moved apart telescopically by fluid pressure acting e.g. upon end faces 16a. <IMAGE>

Description

SPECIFICATION Method and apparatus for pressure testing components This invention concerns a method for pressure testing shell-like components of tubular crosssection, such as castings or machined parts wherein pressure is applied in a radial direction to the interior walls of the components.

Testing such components using a pressure hydraulic fluid applied directly to the inner walls of the components can be hazardous because of the high pressure sometimes necessary and the possibility of entrained air which can give rise to an explosive hazard in the event of any failure of a component.

It is an object of the present invention to provide a method of testing a shell-like component of circular cross-section which overcomes the problem aforesaid.

According to the present invention there is provided a method of testing a shell-like component of tubular cross-section comprising the steps of providing an elastic sleeve extending between the opposed end caps, positioning said sleeve within the component and inflating the sleeve with hydraulic fluid to the required test pressure, the arrangement being such that an initial stage of the inflation causes the sleeve to cooperate with said end caps and the component under test to form an effective pressure seal which prevents leakage of fluid from the interior of the sleeve at the test pressure.

The opposed end caps are preferably of unitary construction and may be connected by a mandrel which may be of telescopically extendible construction.

The invention will be further apparent from the following description, with reference to the single figure of the accompanying drawing, which shows, by way of example only, in cross-section, one form of apparatus for pressure testing a casting in the form of an openended conical shell which may, for example, be a bomb casing.

Referring to the drawing, it will be seen that the conical shell C is mounted in a vertical position on a lower end cap 10 which is rigidly secured to the frame of the test machine. A cylindrical elastic sleeve 11, preferably moulded from rubber, extends axially within the shell C and has a formed lower end of a shape corresponding with an annular profile 1 2 machined in the lower end cap 1 0.

The upper annular end of the sleeve 11 also has a formed section which is complementary with the shape of the undersurfaces of an upper end cap 1 3. The upper end cap 1 3 may be screwed by means of a nut 1 4 into a mandrel part 1 5 having an upper conical end 1 6 to clamp the upper annular end of the sleeve 11 between the conical part 1 6 and the undersurface of the end cap 1 3. The mandrel part 1 5 is slidable within a cylinder 1 7 in a lower mandrel part 1 8 which passes through the end cap 10.Flats 1 spa and 1 8a are machined on the mandrel parts 1 5 and 1 8 respectively and engaged by pins 1 9 and 20 to prevent relative rotation between the parts 15, 18 and 10.

A bore 21 extends upwardly through the mandrel part 1 8 into the cylinder 1 7 and bores 22 extend outwardly from the cylinder 17 through the part 18.

In use the apparatus is assembled as described and hydraulic fluid under pressure is pumped through the bore 21 for flow through the bores 22 into the interior of the sleeve 11 to cause the sleeve 11 to inflate and press outwardly against the interior walls of the shell C. During an initial part of the inflation the mandrel parts 1 5 and 1 8 move apart telescopically by virtue of pressure on the end faces 1 6a of the prt 16, and the upwardly directed surfaces of the part 18, firmly forcing the upper annular end of the sleeve against the inner wall of the conical shell and the lower annular end of the sleeve against the profile 1 2 to form an effective pressure seal which holds as the pressure is increased to the full test pressure which may be as high, for example, as 10,000 psi.

Preferably the end caps 1 3 and 10 are of one-piece construction.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof as defined by the appended claims.

Thus for example with components of more complex shape an elastic sleeve of corresponding shape may be employed or a plurality of elastic sleeves may be used which can be individually inflated to the same or different pressures as desired.

1. A method of testing a shell-like component of tubular cross-section comprising the steps of providing an elastic sleeve extending between opposed end caps, positioning said sleeve within the component and inflating the sleeve with hydraulic fluid to the required test pressure, the arrangement being such that an initial stage of the inflation causes the sleeve to cooperate with said end caps and the component under test to form an effective pressure seal which prevents leakage of fluid from the interior of the sleeve at the test pressure.

2. Apparatus for testing a shell-like component of tubular cross-section comprising an elastic sleeve extending between opposed end caps and adapted to be fitted so as to extend axially within the component to be tested, means for inflating said elastic sleeve with hydraulic fluid to a required test pressure, the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method and apparatus for pressure testing components This invention concerns a method for pressure testing shell-like components of tubular crosssection, such as castings or machined parts wherein pressure is applied in a radial direction to the interior walls of the components. Testing such components using a pressure hydraulic fluid applied directly to the inner walls of the components can be hazardous because of the high pressure sometimes necessary and the possibility of entrained air which can give rise to an explosive hazard in the event of any failure of a component. It is an object of the present invention to provide a method of testing a shell-like component of circular cross-section which overcomes the problem aforesaid. According to the present invention there is provided a method of testing a shell-like component of tubular cross-section comprising the steps of providing an elastic sleeve extending between the opposed end caps, positioning said sleeve within the component and inflating the sleeve with hydraulic fluid to the required test pressure, the arrangement being such that an initial stage of the inflation causes the sleeve to cooperate with said end caps and the component under test to form an effective pressure seal which prevents leakage of fluid from the interior of the sleeve at the test pressure. The opposed end caps are preferably of unitary construction and may be connected by a mandrel which may be of telescopically extendible construction. The invention will be further apparent from the following description, with reference to the single figure of the accompanying drawing, which shows, by way of example only, in cross-section, one form of apparatus for pressure testing a casting in the form of an openended conical shell which may, for example, be a bomb casing. Referring to the drawing, it will be seen that the conical shell C is mounted in a vertical position on a lower end cap 10 which is rigidly secured to the frame of the test machine. A cylindrical elastic sleeve 11, preferably moulded from rubber, extends axially within the shell C and has a formed lower end of a shape corresponding with an annular profile 1 2 machined in the lower end cap 1 0. The upper annular end of the sleeve 11 also has a formed section which is complementary with the shape of the undersurfaces of an upper end cap 1 3. The upper end cap 1 3 may be screwed by means of a nut 1 4 into a mandrel part 1 5 having an upper conical end 1 6 to clamp the upper annular end of the sleeve 11 between the conical part 1 6 and the undersurface of the end cap 1 3. The mandrel part 1 5 is slidable within a cylinder 1 7 in a lower mandrel part 1 8 which passes through the end cap 10.Flats 1 spa and 1 8a are machined on the mandrel parts 1 5 and 1 8 respectively and engaged by pins 1 9 and 20 to prevent relative rotation between the parts 15, 18 and 10. A bore 21 extends upwardly through the mandrel part 1 8 into the cylinder 1 7 and bores 22 extend outwardly from the cylinder 17 through the part 18. In use the apparatus is assembled as described and hydraulic fluid under pressure is pumped through the bore 21 for flow through the bores 22 into the interior of the sleeve 11 to cause the sleeve 11 to inflate and press outwardly against the interior walls of the shell C. During an initial part of the inflation the mandrel parts 1 5 and 1 8 move apart telescopically by virtue of pressure on the end faces 1 6a of the prt 16, and the upwardly directed surfaces of the part 18, firmly forcing the upper annular end of the sleeve against the inner wall of the conical shell and the lower annular end of the sleeve against the profile 1 2 to form an effective pressure seal which holds as the pressure is increased to the full test pressure which may be as high, for example, as 10,000 psi. Preferably the end caps 1 3 and 10 are of one-piece construction. It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof as defined by the appended claims. Thus for example with components of more complex shape an elastic sleeve of corresponding shape may be employed or a plurality of elastic sleeves may be used which can be individually inflated to the same or different pressures as desired. CLAIMS

2. Apparatus for testing a shell-like component of tubular cross-section comprising an elastic sleeve extending between opposed end caps and adapted to be fitted so as to extend axially within the component to be tested, means for inflating said elastic sleeve with hydraulic fluid to a required test pressure, the arrangement being such that an initial stage of the inflation causes the ends of said sleeve to cooperate with said end caps and the component under test to form an effective pressure seal which prevents leakage of fluid from the interior of the sleeve at test pressure.

3. Apparatus according to claim 2 wherein the opposed ends of the sleeve are profiled to have shapes corresponding with the shapes of the inwardly directed surfaces of the end caps which they abut.

4. Apparatus according to claim 2 or claim 3 wherein one of said end caps is adapted to be screwed into a first mandrel part to trap one end of the sleeve therebetween, said fist mandrel part being telescopically slidable in a cylinder formed in a second mandrel part extending through the other end cap.

5. Apparatus according to claim 4 including means to prevent relative rotation of said two mandrel parts and said other end cap.

6. Apparatus according to claim 4 or claim 5 wherein said hydraulic fluid is admitted to the interior of said sleeve via a bore leading into said cylinder, there being at least one aperture between said cylinder and the outside of said second mandrel part, whereby when the sleeve is inflated the mandrel parts are initially driven apart to perfect the seal at the ends of the sleeve.

7. Apparatus according to any one of claims 2-6 wherein said sleeve is comprised by a rubber moulding.

8. Apparatus according to any one of claims 2-7 wherein there are a plurality of said sleeves and associated parts adapted to be fitted at spaced axial locations within a component to be tested.

9. Apparatus according to claim 8 wherein said plurality of sleeves can be inflated to different test pressures.

1 0. A method for testing a shell-like component of tubular cross-section substantially as described herein with reference to and as illustrated by the figure of the accompanying drawing.

11. Apparatus for testing a shell-like component of tubular cross-section substantially as described herein with reference to and as illustrated by the figure of the accompanying drawing.