GB2377493A

GB2377493A - Clamp assembly for fixing two transducers to opposite sides of a member

Info

Publication number: GB2377493A
Application number: GB0111771A
Authority: GB
Inventors: David Peall
Original assignee: TECHNOLOGY CAMBRIDE Ltd AB
Current assignee: TECHNOLOGY CAMBRIDE Ltd AB
Priority date: 2001-05-14
Filing date: 2001-05-14
Publication date: 2003-01-15
Also published as: GB0111771D0

Abstract

A transducer clamp assembly has two transducer mountings 13,14 for supporting respective transducers 15a,15b. The mountings are located opposite one another on a support structure 10, at least one of the mountings is movable relative to the other on the support structure so that the transducers can be brought into engagement with opposite sides of a member such as a pipe 6. The support structure includes a clamp system 11a,11b for clamping the mountings 13,14 on the member. The device is designed to allow transducers to be fixed to a range of different diameter members such as conduits for the cooling systems of refridgeration or air conditioning systems.

Description

TRANSDUCER CLAMP ASSEMBLY This invention relates to a clamp assembly for holding a pair of transducers in contact with a member, such as a conduit forming part of a cooling system of a refrigeration system or air conditioner.

It is desirable to be able to detect the production of gas bubbles in the liquid refrigerant of a compression refrigeration system as may be caused by loss of refrigerant. One such system for detecting these gas bubbles is the TIF4000A electronic sight glass manufactured by TIF Instruments, Incorporated. This comprises a pair of transducer clamps and associated transducers connected to a signal processing circuit. In use, the transducer clamps are used to hold the transducers firmly in contact with a conduit forming part of the cooling system of a refrigeration system. One transducer acts as a transmitter and the other as a receiver and, by performing suitable signal processing, the signal processing circuit can detect the presence of gas bubbles in the liquid refrigerant.

A disadvantage of this type of transducer clamp is that attaching the sensors to the conduit is complex.

In accordance with one aspect of the present invention, a transducer clamp assembly has first and second transducer mountings for supporting respective transducers in use, the mountings being located opposite one another on a support structure, at least one of the mountings being movable relative to the other on the support structure so that the transducers can be brought into engagement with opposite sides of a member in use, the support structure including a clamp system for clamping the mountings on the member.

Hence, the invention provides a transducer clamp assembly that can hold two transducers firmly in contact with a conduit and arranged diametrically opposite around the conduit.

Normally, the clamp system of the transducer clamp assembly is releasable. However, in some instances it may be desirable that the clamp system cannot be released once it has been fastened.

In a preferred embodiment, the support structure comprises a U-shaped bar on which at least one of the mountings is slidably mounted and as such, the second mounting may have two holes through which the ends of the U-shaped bar protrude.

The U-shaped bar may have two threaded ends and the clamp system may comprise two fasteners with internal screw threads corresponding to the screw threads of the ends of the U-shaped bar so that when rotated the fasteners cause the second mounting to move relative to the first mounting.

The first mounting may fit over the curved section of the U-shaped bar. In this case, the first mounting may comprise two parts, one of which is an interference fit within the other, the U-shaped bar being trapped between the two parts. Alternatively, the first mounting may clip or it may be moulded onto the curved section of the Ushaped bar.

In another embodiment, the support structure comprises two parallel bars, each threaded at both ends. The first mounting has two threaded inserts into which the bars are screwed and the second mounting is slidably mounted on the bars. Several modifications may be made to this embodiment whilst remaining within the scope of the invention by one of ordinary skill in the art.

The clamp system may be operated using a variety of tools such as a spanner or a socket and ratchet handle. However, preferably, the clamp system may be operated by hand.

It is possible that the clamp system may be permanently mounted on the second mounting. For example, the above mentioned fasteners may be captive with the second mounting.

Preferably, the transducers are permanently mounted on the first and second mountings and typically, these transducers are electroacoustic transducers. Their normal frequency of operation will be in the ultrasonic spectrum.

Curved shims may be fitted to the inner faces of the transducers in order to aid their centralisation on the member to which they are being fixed. These shims may be made of copper or brass. Alternatively, they may be made of another metal or acoustically compatible material.

In accordance with a second aspect of the invention, there is provided a method of clamping two transducers to a liquid carrying conduit using a transducer clamp assembly according to the first aspect of the invention, wherein the conduit is disposed between the transducers supported on the first and second mountings and the clamp system clamps the transducers on the conduit.

Typically, the liquid carrying conduit will form part of the cooling system of a refrigeration system.

The invention is useful in a variety of applications, particularly for clamping ultrasonic transducers to a conduit forming part of a cooling system of a refrigeration system or air conditioner, where the transducers are used for the detection of gas bubbles within the liquid refrigerant contained in the conduit.

An example of a transducer clamp assembly according to the present invention will now be described and contrasted with a known assembly with reference to the accompanying drawings, in which :Figure 1 shows a transducer clamp as used in the TIF4000A electronic sight glass ; Figure 2 shows a schematic drawing of one embodiment of the invention ; Figure 3 shows a 3D perspective view of this embodiment ; and Figure 4 shows a schematic drawing of another embodiment of the invention.

Figure 1 shows one of the transducer clamps. The transducer clamp comprises clamp body 1 to which is fixed transducer 2. Clamp body 1 is C-shaped in cross-section and has a tapped hole (not shown). Screw 3 is fitted through this tapped hole so that when operated by turning knurled handle 4, a pad 5 is brought into contact with conduit 6, disposed between pad 5 and transducer 2. In this way by tightening screw 3 transducer 2 is held firmly in contact with conduit 6.

Figure 2 shows one embodiment of a transducer clamp assembly according to the invention. A 3D perspective view of this embodiment is shown in Figure 3, with the corresponding parts having the same reference numerals.

The transducer clamp assembly comprises a U-shaped metal bar 10 with two threaded ends lla and llb, two fasteners with corresponding screw threads 12a and 12b and two transducer mountings 13 and 14 to which two transducers 15a and 15b are attached. Two copper shims 16a and 16b are provided to aid the centralisation of the transducers 15a and 15b around conduit 6.

In use, the U-shaped metal bar 10 is passed over the conduit so that shim 16a is brought into engagement with conduit 6. The second mounting 14 is then slid along the parallel legs of U-shaped metal bar 10 until shim 16b is also in engagement with conduit 6 in a position diametrically opposite to that of shim 16a. The fasteners 12a and 12b are now tightened until sufficient force is applied to conduit 6 via shims 16a and 16b so that the transducer clamp assembly is held firmly in position.

Thus, acoustic signals transmitted by one transducer can be propagated through the conduit 6 and its contents and may be detected by the diametrically opposite transducer.

A possible arrangement for the first mounting 13 is shown in Figure 3. In this case, the first mounting comprises two parts 13a and 13b. The second part 13b is an interference fit within the first part 13a and the first

mounting 13 fits over the curved section of U-shaped metal bar 10 by trapping the bar between these two parts.

The fasteners 12a and 12b shown in Figure 3 are designed so that they may be operated by hand and they may have a knurled finish to assist with this.

Another embodiment of the invention is shown in Figure 4. This embodiment has two parallel bars 20a, 20b in place of U-shaped metal bar 10. They are both threaded at each end so that they can be screwed into threaded inserts (not shown) in the first mounting 13. Otherwise, this embodiment is the same as that shown in Figures 2 and 3 as described above. The parts in Figure 4 corresponding to those shown in Figures 2 and 3 have been given the same reference numerals.

Such clamp assemblies are particularly advantageous as they allow the transducers to be fixed to a range of different diameters of conduit.

Claims

CLAIMS 1. A transducer clamp assembly having first and second transducer mountings for supporting respective transducers in use, the mountings being located opposite one another on a support structure, at least one of the mountings being movable relative to the other on the support structure so that the transducers can be brought into engagement with opposite sides of a member in use, the support structure including a clamp system for clamping the mountings on the member.
2. A transducer clamp assembly according to claim 1, wherein the clamp system is releasable.
3. A transducer clamp assembly according to either of the preceding claims, wherein the support structure comprises a U-shaped bar upon which the second mounting is slidably mounted.
4. A transducer clamp assembly according to claim 3, wherein the second mounting has two holes through which the ends of the U-shaped bar protrude.
5. A transducer clamp assembly according to claim 4, wherein the U-shaped bar has two threaded ends and the clamp system comprises two fasteners with internal screw threads corresponding to the screw threads of the ends of the U-shaped bar so that, when rotated, the fasteners cause the second mounting to move relative to the first mounting.
6. A transducer clamp assembly according to any of claims 3 to 5, wherein the first mounting fits over the curved section of the U-shaped bar.
7. A transducer clamp assembly according to claim 6, wherein the first mounting comprises two parts, one of which is an interference fit within the other, the first mounting fitting over the curved section of the U-shaped bar by trapping it between the two parts.
8. A transducer clamp assembly according to claim 6, wherein the first mounting clips onto the curved section of the U-shaped bar.

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9. A transducer clamp assembly according to claim 6, wherein the first mounting is moulded onto the curved section of the U-shaped bar.
10. A transducer clamp assembly according to claim 1 or claim 2, wherein the support structure comprises two parallel bars upon which the second mounting is slidably mounted.
11. A transducer clamp assembly according to claim 10, wherein the second mounting has two holes through which the parallel bars protrude.
12. A transducer clamp assembly according to claim 11, wherein the parallel bars each have a threaded end and the clamp system comprises two fasteners with internal screw threads corresponding to the screw threads of the ends of the parallel bars so that, when rotated, the fasteners cause the second mounting to move relative to the first mounting.
13. A transducer clamp assembly according to any of claims 10 to 12, wherein the first mounting fits onto the ends of the parallel bars.
14. A transducer clamp assembly according to claim 13, wherein the first mounting has two threaded inserts and the ends of the parallel bars have corresponding screw threads.
15. A transducer clamp assembly according to claim 13, wherein the first mounting is moulded into the ends of the parallel bars.
16. A transducer clamp assembly according to any of the preceding claims, wherein the clamp system can be operated by hand.
17. A transducer clamp assembly according to any of the preceding claims, wherein the clamp system is permanently mounted on the second mounting.
18. A transducer clamp assembly according to any of the preceding claims, wherein the transducers are permanently mounted on the first and second mountings.
19. A transducer clamp assembly according to claim 18, wherein the transducers are electroacoustic transducers.

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20. A transducer clamp assembly according to claim 19, wherein the transducers operate at an ultrasonic frequency.
21. A transducer clamp assembly according to any of claims 18 to 20, wherein the transducers have a curved shim attached to their inner face.
22. A transducer clamp assembly according to claim 21, wherein the shim comprises copper.
23. A transducer clamp assembly substantially as hereinbefore described with reference to the accompanying drawings.
24. A method of clamping two transducers to a liquid carrying conduit using a transducer clamp assembly according to any of the preceding claims, wherein the conduit is disposed between the transducers supported on the first and second mountings and the clamp system clamps the transducers on the conduit.
25. A method according to claim 24, wherein the liquid carrying conduit forms part of the cooling system of a refrigeration system.