GB2208904A

GB2208904A - Adaptor for tank contents gauge

Info

Publication number: GB2208904A
Application number: GB8819909A
Authority: GB
Inventors: Stanley Morgan Maude
Original assignee: Tankmaster Ltd
Current assignee: Tankmaster Ltd
Priority date: 1987-08-20
Filing date: 1988-08-22
Publication date: 1989-04-19
Also published as: GB8819909D0

Abstract

An adaptor is described for connecting two pressure measurement devices to respective ones of two coaxial tubes. The adaptor comprises a body carrying first and second hollow coupling elements, connected by a conduit through the body, for attachment respectively to the outer of the coaxial tubes and a first pressure measurement device. The adaptor includes an aperture in the upper surface of the body coaxial with the first coupling element. The inner tube ends at the aperture with a fluid tight fit and an extension member fitted and sealed to the inner tube carries the second pressure measurement device. <IMAGE>

Description

ADAPTOR FOR TANK CONTENTS GAUGE The present invention relates to the gathering of pressure readings from a tank for compiling various data regarding the contents of the tank, such as depth,weight and specific gravity. One method of gathering such readings is using a pair of coaxially mounted bubble tubes down which compressed gas is passed. Pressure measurement devices are fitted at the top of the tubes. The invention particularly concerns an adaptor for fitting the two pressure measurement devices to the respective tubes.

At present the pressure measurement devices are fitted to the tubes on site using a system of -- compression fittings which are difficult to use and are often subject to leaks. For reliable readings it is important that the joints are leak free and so it is the object of the present invention to provide an improved system for making this connection.

According to the present invention there is provided an adaptor for fitting two pressure measurement devices to read the pressures in respective ones of two coaxial tubes, the adaptor being manufactured in one piece and comprising an elongate body defining a conduit between a first tubular coupling element via which a connection may be made to the outer of the coaxial tubes and a second tubular coupling element adapted to receive a first pressure measurement device; and an aperture in the body coaxial with the first tubular coupling element and of a diameter smaller than the internal diameter of the first tubular coupling element.

Advantageously the inner of the coaxial tubes makes a screw threaded connection with an extension piece carrying the second pressure measurement device, one of the inner tube and the extension piece passing through the aperture.

The inner tube preferably has a shoulder or collar via which a seal may be made with the inner wall of the body around the aperture.

In practice it is convenient to fit the# pressure measurement devices to their respective coupling element/ extension piece at the factory so that only the tubes need to be fitted and sealed on site. This reduces the chance of error and of leaks.

The invention will now be described, by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an adaptor according to the invention, Figure 2 is a cross section of the adaptor of Figure 1 fitted to coaxial bubble tubes, and Figures 3 and 4 are respectively top and bottom views of the adaptor of Figure 1.

The device illustrated in the drawings is an adaptor for coupling two pressure measurement devices 6,7, to respective ones of two coaxially mounted bubble tubes 8,9.

The adaptor comprises a body 10 for location outside the tank in use, which body is an elongate hollow horizontal member defining a conduit 11 between a first coupling element 12 and a second coupling element 13.

The first coupling element 12 extends downwardly, is tubular and is screw threaded on the outer surface to mate with an internal thread at the top of the outer bubble tube 8. This threaded joint will additionally be sealed to withstand the high pressure of the gas in the tube. The second coupling element 13 extends upwardly, is tubular, and is screw threaded on the inner surface to receive a pressure measurement device 6 mated thereto in a sealed threaded connection. The pressure measurement device 6 reads the pressure in the outer bubble tube 8 via the conduit 11. Note that there are no constrictions between the bubble tube and the device 6. The conduit through the body is always of at least as great a cross sectional area as the cross sectional area of the space between the bubble tubes 8,9.

-The inner tube 9 of the two coaxial tubes ends in a thread which may be internal or externnal. In the drawing of Figure 2 an external thread is illustrated on a reduced diameter portion 15 of the tube. To this tube 9 an inner tube extension 17 is fitted by a sealed screw threaded connection to the portion 15. In this case the portion 15 extends through al, aperture 18 in the upper surface of the body 10. A shoulder 19 on the inner tube engages the inner wall of the body around the aperture and the application of a sealant to the shoulder will ensure that a good seal is made.

The screwing action of the tube and the extension will draw the shoulder 19 upwardly against the body wall.

Thus although the inner tube passes through the conduit 11, the contents of the inner tube remains isolated from the contents of the outer tube and the conduit.

In an alternative arrangement, the inner tube 9 ends with an internal thread and a small collar (not shown).

The inner tube extension has a threaded protrusion which extends through the aperture 18 and mates with the tube 9. The collar at the top of the tube in this arrangement prvides a sufficient surface area for a good seal to be made with the inner surface of the body wall around the aperture in the same way as that already described with respect to the illustrated embodiment. The inner tube extension carries the second pressure measurement device 7 sealed thereto for measuring the pressure in the inner tube. If required the pressure measurement devices 6, 7 may be permanently fixed and sealed to the adaptor and inner tube extension respectively, for example by glue, so that this joint does not have to be made on site.

This leaves only two joints that have to be sealed on site. However the actual joint is an easier one to make than those used hitherto and the sealant more straightforward to apply.

The adaptor iS manufactured in one piece as a casting, and includes a shoulder 21 around the seat of the first coupling element 12, a shoulder 22 around the seat of the second coupling element 13 and a raised disc portion 23 which houses the aperture 18.

In an alternative arrangement the pressure measurement device 7 may be screw threaded directly onto tne inner tube without the intermediary of the extension member 17.

Where the pressure measurement device 6 is to be fitted to the adaptor at the factory, the screw threaded connection may be replaced by a simple mating connection which is sealed with adhesive.

Claims

1 An adaptor for fitting two pressure measurement devices to read the pressures in respective ones of two coaxial tubes, the adaptor being manufactured in one piece and comprising an elongate body defining a conduit between a first tubular coupling element via which a connection may be made to the outer of the coaxial tubes and a second tubular coupling element adapted to receive a first pressure measurement device; and an aperture in the body coaxial with the first tubular coupling element and of a diameter smaller than the internal diameter of the first tubular coupling element.

2. An adaptor according to claim 1 wherein a first pressure measurement device is fitted and sealed to the second tubular coupling element.

3. An adaptor according to claim 1 or 2 including inner and outer tubes, the first tubular coupling element and the outer tube having cooperating screw threads whereby they can be connected together.

4. An adaptor according to any of the preceding claims wherein the second coupling element is screw threaded to receive a first pressure measurement device screwed thereto.

5. An adaptor according to claim 3 including a member carrying a second pressure measurement device, the said member and the inner tube have cooperating screw threads whereby they can be connected together, one of the said member and the inner tube passing through the aperture.

6. An adaptor according to claim 5 wherein the inner tube is provided with a surface substantially parallel to the inner wall if the body around the.

aperture whereby a seal can be made to prevent leakage through the aperture from the'conduit.

7. An adaptor substantially as herein described with reference to the accompanying drawings.