GB2167158A - Improvements relating to pipe supports - Google Patents

Abstract

In a pipe support (10), a pipe is movably supported by a spring (13) acting between a first member (23) and a plate (22) associated with a second member (21) of pipe connection means (15). Restraining means (30), comprising a first element (31) constrained relative to the first member (23) and a second element (32) carried on the second member (21), is such that by suitably positioning the second element (32) on the second member (21a), the elements (31, 32) may be releasably interengaged so as to restrain movement of the second member (21), and hence that of the pipe. The second element (32) is threadedly engaged with the second member (21a) and is threadedly interengageable with the first element (31). Free play existing between the first member (23) and the first element (31) facilitates interengagement and non- violent release of the restraining elements (31, 32). The restraining means (30), or modifications thereof, are suitable for "constant effort" and/or "variable effort" supports. <IMAGE>

Description

SPECIFICATION Improvements relating to pipe supports Description of Invention This invention relates to pipe supports and is particularly concerned with pipe supports of the kind (hereinafter referred to as being of the kind specified) comprising means suitable for attaching the support to a main structure, means suitable for connecting a pipe to the support, and spring means acting between the attachment means and the connection means to enable the pipe, when so connected, to be movably supported by the spring means.

Movement of the supported pipe may, for example, be caused by temperature changes, changes in the weight of the pipe and its contents, land subsidence or earth tremors. Pipe supports of the kind specified are commonly used for supporting pipes which convey any of a variety of substances, such pipes for example being pipes which convey steam in a power station.

In general, pipe supports of the kind specified are of either of two types known respectively as "constant effort supports and "variable effort" supports. The spring force in pipe supports of the "constant effort" type remains substantially constant for a range of movement of a pipe supported by the support, whereas the spring force in pipe supports of the "variable effort" type varies according to the movement of the pipe.

The present invention, although primarily intended for application to pipe supports of the "constant effort" type, is nonetheless also applicable to pipe supports of the "variable effort" type.

It is sometimes desirable to be able to restrain a supported pipe against movement. For example, during construction of a system of supported pipes, it may be desirable, in order to ensure satisfactory pipe positioning, to be able to restrain at least the connection means, and hence the pipe, in a position corresponding generally to the expected pipe position under the expected normal loading of the support. Additionally, when a cleaning fluid is to be passed through a supported pipe, it is desirable to prevent the pipe from moving under the weight of the cleaning fluid when the fluid is in the pipe, by restraining the spring means against movement prior to admission of the cleaning fluid to the pipe.

Prior to the present invention, pipe supports have been proposed having means for restraining the connection means and/or the spring means against movement, but the restraining means of such conventional supports can sometimes be inaccessible to otherwise difficult to operate and/or can suffer from the disadvantage that when the restraining means is to be released after a period of restraint, it is difficult to determine if the support is loaded to the same extent as when the connection means or spring means was initially restrained: if not, the support may "give" unexpectedly and potentially dangerously when the restraining means is released.

It is an object of the invention to provide a new or improved pipe support of the kind specified.

According to the present invention there is provided a pipe support of the kind specified comprising first and second members which undergo relative movement corresponding to movement of the spring means and/or movement of the connection means, a first restraining element constrained with respect to the first member, and a second restraining element adjustably positionable on the second member, such that by suitable positioning of said second restraining element, the first and second restraining elements may be releasably interengaged so as to restrain movement of the spring means and/or the connection means.

Preferably, said movement is restrainable in two opposite directions.

The spring means or the connection means are preferably restrainable at least at some intermediate position within the operating range of the support, so as to prevent further compression (e.g. during cleaning) or expansion (e.g. when a pipe is not connected to the connection means) of the spring means.

Preferably, said second element is infinitely adjustable positionally, although alternatively it may be positionable at a plurality of discrete positions if desired.

The first element may be provided by a portion of the first member, although preferably the first element is separate from the first member, to avoid problems which could otherwise arise from internal movements of the support in use, but is formed so as to be able to interfit with the first member.

Preferably, the first element is interposed between the first member and the second member.

Preferably, the second member comprises a threaded rod and the second element is threadedly enagaged therewith, so that the second element may be rotated to cause it to change its position on the rod in order to bring about engagement or disengagement of the second element with or from the first element.

Preferably, said interengagement between the first and second elements is possible through provision of complementary threads on the first and second elements. Preferably, an external thread is provided on the second element and a complementary internal thread is provided on the first element.

Preferably, the pitches of all said threads (on the rod and on the first and second elements) are substantially equal, to facilitate engagement and disengagement of said elements.

Preferably rotation of the first element is constrained with respect to said first member.

Preferably, the first member is a plate of a housing of the support, and the second member is a load-supporting draw bar of the connection means.

Alternatively, the first member may be a moving part of the connection means or the spring means, and the second member may be fixed with respect to a housing of the support.

Preferably, there is some free play between the first member and first element. Thus, if release of the restraining means is effected when sufficient clearance is visible between the first element and the first member, the restraining means may be released without violent movement of the spring means or pipe on release.

The support may comprise manually operable adjustment means which is operative to change the effective loading of the support, in order to enable said clearance to be obtained under conditions where it is not possible to vary the actual load.

Where the second member is said threaded rod, and where the first and second restraining elements have complementary threads, then in order to ensure that the relative orientation of the complementary threads, when said elements meet, is capable of permitting initiation of threaded engagement between said elements, any such free play, comprising axially rotatative free play together with linear free play, must correspond to at least one complete rotation of the second restraining element.

Where rotation of the first restraining element is constrained (e.g. to permit onehanded operation of the restraining means by rotating only the second element), sufficient linear free play is important for ensuring ease of operation of the restraining means irrespective of the relative positions of the first and second members.

The first element may be constrained linearly with respect to the first member by respective flanges on the first element which overly oppositely facing surfaces of the first member, and may be constrained rotatively by projections on the first member which arrestingly engage edges of at least one of the flanges on excessive rotation thereof.

When the first and second elements are interengaged, abutment of said flanges against said respective surfaces of the first member may be responsible for restraining relative movement between said members in respective opposite directions.

The support may be of the constant effort type, in which case, since the draw bars of such supports do not tilt greatly in use relative to the respective support housings, the first element may have constraining flanges which closely overlie, and substantially follow the contours of, said oppositely facing surfaces of the first members.

Alternatively, the support may be of the variable effort type, in which case the draw bar may pivot considerably during use, so that where the restraining means is operative on the draw bar, the first element may have flanges which overlie said oppositely facing surfaces of the first member, but which (for example) diverge away from said surfaces.

Several embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a "constant effort" type pipe support embodying the invention, the support being partly sectioned on its right hand side, as seen in the drawing; Figure 2 is a fully sectional side elevation, to a larger scale than Fig. 1, of restraining means of the support of Fig. 1; Figure 3 is a partly sectional plan view of said restraining means, on the line Ill-Ill of Fig.

1; Figure 4 is a sectional side elevation, to a reduced scale, of an alternative spring unit for supports in accordance with the invention, the alternative spring unit being suitable for both "constant" and "variable" type supports; Figure 5 is a cross-sectional side elevation of a support-from-above "variable effort" support embodying the invention; and Figure 6 is a cross-sectional side elevation of a "support-from-below" variable effort support embodying the invention.

Referring first to Figs. 1 to 3 of the drawings, a constant-effort type pipe support 10 comprises a steel plate 11 welded to a spring unit 12 within which a spring 13 is housed. A device 14 is provided for use in attaching the support 10 to a main structure (e.g. a wall or gantry of a building or ship). The support 10 may be used to support a load, for example a steam-conveying pipe, via connection means 15 comprising a turn-buckle 16 which is connected to one arm 17 of a bell crank lever 18.

The spring 13 lies and acts between a steel plate first member 23 and a steel plate 22, to which plate 22 a second member, namely a draw bar 21, is connected. The bell crank lever 18 is pivotable about a shaft 19 and has a second arm 20 which is connected to the draw bar 21. When a load, for example a pipe, is supported via the turn-buckle 16, an anti-clockwise torque about the shaft 19, due to the load, is applied to the lever 18 so as to pull the draw bar 21 to the left in Fig. 1, said pulling to the left being opposed by the spring 13, which is compressed by said pulling, until equilibrium is attained.Should a pipe so supported by the support 10 undergo movement, the support 10 is able to pivot about a connection 14a between the attachment device 14 and the plate 11 in such a way that the compression of the spring 13 remains relatively constant compared with variations in compression which could occur in the absence of such pivoting. A second bell crank lever (not visible in the drawings) identical to the lever 18 and having corresponding connections with the turn-buckle 16, the draw bar 21 and the shaft 19, is located on the far side (as seen in Fig. 1) of the plate 11.

When installing a pipe system, it is convenient, in order to ensure that the pipes are installed approximately in the average positions which they will occupy in use, to set any pipe supports to their normal loading to be expected in use until the pipe system is complete. Additionally, it is occasionally desirable to clean pipes supported by the pipe supports, for example by passing clean fluid therethrough, and since such cleaning fluid can often be heavier than substances normally conveyed by the pipes, it is desirable to able to restrain the supports against excessive compression of their respective springs.

In order to fulfil these needs, the support 10 is provided with restraining means 30.

The restraining means 30 comprises a first restraining element 31, which is constrained relative to the first member 23 by being located partially within an aperture 23a in the member 23 and by being oriented so that extremities of rectangular flanges 31a and 31b on the element 31 overlie oppositely facing surfaces of the member 23. The aperture 23a is of complementary shape to the flanges 31a and 31b, but is tranversely oriented relative thereto. The draw bar 21 (i.e. said second member) has an externally threaded portion 21a which passes through a bore in the element 31, but which is not threadedly engaged therewith. There is, in fact, sufficient difference in diameter between the surface of said bore and the portion 21a to ensure that the draw bar 21 can move to the right or to the left (as seen in the drawings) without being significantly impeded by the presence of the element 31.Rotation of the element 31 relative to the member 23 is constrained by four projections 23' capable of arrestingly by abutting edges of the flange 31a, said projections conveniently being provided on the member 23 after assembly of the pipe support. The restraining means 30 further comprises a second restraining element 32 which is threadedly engaged with the portion 21a, so that rotation of the element 32 on the portion 21a results in longitudinal movement of the element 32 along the portion 21a. When it is not desired to restrain the draw bar 21 against movement. the element 32 is positioned so as to lie adjacent an enlarged portion 21b of the draw bar 21, substantially in the position shown in broken lines in Fig. 2.However, when it is desired to restrain the draw bar 21 against movement, the element 32 is rotated so as to move longitudinally along the portion 21a so as to abut the element 31. The element 32 has an external thread 33, which is complementary to an internal thread 34 on the surface of an enlarged portion 35 of the bore of the element 31. The positioning of the projections 23' and the spacing of the flanges 31a and 31b is such that there is free play between the element 31 and the member 23 corresponding to at least one turn of rotational (and corresponding longitudinal) movement of the element 32 relative to the element 31. Thus, continued rotation of the element 32 so as to induce movement thereof to the right results in threaded interengagement between the elements 31 and 32, whatever the position of the draw bar 21.In this manner, movement of the element 32, and hence of the draw bar 21, relative to the element 31 is restrained, and since movement of the element 31 relative to the member 23 is constrained by the flanges 31a and 31b, movement of the draw bar 21 relative to the member 23 is therefore restrained, whatever the position of the draw bar 21.

The threads on the draw bar portion 21a and the elements 31 and 32 are of substantially the same pitch.

As will be seen from Fig. 1 of the drawings, the element 32 is readily manually accessible, via an opening 36 in the plate 11, so that a sole user may readily restrain the draw bar 21 in the manner described above, using only one hand if desired.

When it is desired to release the restraining means 30 by unscrewing the element 32 from the element 31, it is wise to ensure that the loading on the support 10 is substantially the same as that experienced when the draw bar 21 was first restrained, in order to avoid any sudden movement of the supported pipe when the restraining means 30 is released.

The separation of the flanges 31a and 31b is greater than the thickness of the member 23, so that when a clearance is visible between the flanges 31a and 31b and respective adjacent surfaces of the plate 23, it may be deduced that the loading is conducive to release of the restraining means 30 without such sudden movement. Said clearance may be achieved by changing the actual load connected to the support 10, where possible, or by rotating an adjustment bolt 18' on the lev- er(s) 18 so as to vary the distance of the line of action of the force in the draw bar from the shaft 19 and thereby change the effective loading on the spring 13 to a value giving said clearance.

Fig. 4 shows an alternative spring unit 412 which may be used in a constant effort support otherwise substantially identical to the support 10 of Figs. 1 to 3. Instead of having a restraining means operative on a draw bar 401 of the unit 412, two externally threaded rod members 421 fixed within the unit 412 are provided, the member 421 passing through a movable steelplate first member 423 on one end of a spring 413 of the unit 412. Each threaded member 421 carries a respective first restraining element 431, generally equivalent to the restraining element 31 hereinbefore described, the elements 431 being constrained via flanges thereon in relation to the plate member 423.Each threaded member 421 carries a respective second restraining element 432, generally equivalent to the element 32 hereinbefore described, which is threadedly engaged with the external thread of the respective threaded member 421. In order to restrain movement of the spring means 413, the elements 432 are rotated so as to move longitudinally along the rods 421, away from "parked" positions substantially adjacent a plate 447, towards the elements 431. External threads of the elements 432 are then threadedly interengaged with respective complementary internal threads (not shown) in enlarged bore portions of respective elements 431, thereby interengaging each pair of elements 431, 432. In this manner movement of the member 423 relative to the members 421 is restrained by flanges of the elements 431, thereby preventing additional compression or expansion of the spring 413.The flanges on the elements 431 having spacings greater than the thickness of the plate 423, to facilitate checking of loading of a pipe support incorporating the spring unit 412 prior to release of the restraining means thereof. The unit 412 may be employed as a variable effort pipe support if desired.

Referring now to Fig. 5 of the drawings a support-from-above variable effort support 510 embodying the invention comprises a fixed housing 500, a draw bar 521 carrying a connection turn-buckle 516, the draw bar 521 being secured at its upper end to a plate 522 which is supported by a spring 513 acting between the housing 500 and the plate 522.

A first restraining element 531 is constrained linearly and rotatively with respect to the housing 500 by flanges thereon which overlie oppositely facing surfaces of a lower plate member 523 of the housing 500. The draw bar 521 extends through the element 531 without significantly being impeded thereby.

The draw bar 521 carries a second restraining element 532 which is threadedly engaged with an external thread on the draw bar 521, the element 532 being movable up the draw bar 521 by rotation thereof on said thread, until an external thead on the element 532 engages a complementary internal thread (not shown) on an enlarged bore portion (not shown) of the member 531, so as to lock the draw bar 521 against movement relative to the housing 500.In such a pipe support of the variable effort type, the orientation of the draw bar 521 may vary considerably during use, and for this reason, flanges of the element 531 diverge away from the respect surfaces of the lower plate 523, in order to prevent unintentional jamming of the support during normal use by interference of said flanges with the member 523, yet to permit the draw bar to be restrained intentionally, in the manner described above, whatever its orientation.

In Fig. 6, a support4rom-below variable effort support 610, generally similar in construction to the support 510 of Fig. 5, is illustrated, having a spring 613 located and acting between a movable plate 622 and a lower member 670 of a housing 600, on the opposite side of the plate 622 from a draw bar 621 on which a pipe may be supported and which is connected to the plate 622. Restraining means comprises a first restraining element 631 and a second restraining element 632 are provided. The element 631 is similar to the element 531 described above and is threadedly engaged with the draw bar 621 which is externally threaded. The element 631 comprises flanges which overlie respective oppositely facing surfaces of an upper plate member 623 of the housing 600, as to be constrained against linear and rotatative movement relative to the member 623.When the element 632 is rotated so as to move downwardly along the draw bar 621 so that an external thread on the element 632 threadedly engages an internal thread (not shown) on an enlarged bore portion (not shown) of the element 631, movement of the draw bar 621 relative to the housing 600 is restrained. The flanges on the element 631 diverge from the plate 623 and additionally, a clearance may exist between the flanges and the member 623 so that the support may be loaded correctly prior to release of the restraining means, by observing said clearance, in order to avoid unnecessarily violent release of the support.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (26)

1. A pipe support of the kind specified comprising first and second members which undergo relative movement corresponding to movement of the spring means and/or movement of the connection means, a first restraining element constrained with respect to the first member, and a second restraining element adjustable positionable on the second member, such that by suitable positioning of said second restraining element, the first and second restraining elements may be releasably interengaged so as to restrain movement of the spring means and/or the connection means.

2. A support according to Claim 1 wherein ~#sai#vement is restrainable in two opposite directions.

3. A support according to Claim 1 or Claim 2 wherein the spring means or-th-e connection mean are restrainable at least at some inter mediate position within the operating range of the support.

4. A support according to any one of Claims 1 to 3 wherein said second element is infinitely adjustable positionally, on the second member.

5. A support according to Claim 4 wherein the second member comprises a threaded rod and the second element is threadedly engaged therewith, so that the second element may be rotated to cause it to change its position on the rod in order to bring about engagement or disengagement of the second element with or from the first element.

6. A support according to Claim 5 wherein said interengagement between the first and second elements is possible through provision of complementary threads on the first and second elements.

7. A support according to Claim 6 wherein an external thread is provided on the second element and a complementary internal thread is provided on the first element.

8. A support according to Claim 6 or Claim 7 wherein the pitches of all of said threads (on the rod and on the first and second ele ments) are substantially equal.

9. A support according to any one of Claims 1 to 3 wherein the second element is positionable at a plurality of discrete positions.

10. A support according to any one of Claims 1 to 9 wherein the first element is separate from the first member, but is formed so as to be able to interfit with the first mem ber.

11. A support according to Claim 10 wherein the first element is interposed be tween the first member and the second mem ber.

12. A support according to Claim 10 or Claim 11 wherein there is some free play be tween the first member and the first element.

13. A support according to Claim 12 com prising manually operable adjustment means which is operative to change the effective loading of the support, in order to obtain clearance between the first element and the first member conductive to non-violent release of the restraining means.

14. A support according to any one of Claims 10 to 13 wherein rotation of the first element is constrained with respect to said first member.

15. A support according to any one of Claims 10 to 14 wherein the first element is constrained linearly with respect to the first member by respective flanges on the first element which overlie oppositely facing surfaces of the first member.

16. A support according to Claim 15 where dependant upon Claim 14 wherein the first element is constrained rotatatively by projections on the first member which arrestingly engage edges of at least one of the flanges on excessive rotation thereof.

17. A support according to Claim 12 or any one of Claims 13 to 16 where dependant on Claim 12, where Claim 12 is itself eventually dependant upon Claim 6, wherein any such free play, comprising axially rotative free play together with linear free play, corresponds to at least one complete rotation of the second restraining element.

18. A support according to any one of Claims 1 to 9 wherein the first element is provided by a portion of the first member.

19. A support according to any one of the preceding claims wherein the first member is a plate of a housing of the support, and the second member is a load-supporting draw bar of the connection means.

20. A support according to any one of Claims 1 to 18 wherein the first member is a moving part of the connection means or the spring means, and the second member is fixed with respect to a housing of the support.

21. A support according to any one of the preceding claims which is of the constant effort type.

22. A support according to any one of Claims 1 to 20 which is of the variable effort type.

23. A support according to Claim 21 where eventually dependant upon Claim 15 wherein the constraining flanges closely overlie, and substantially follow the contours of, said oppositely facing surfaces of the first member.

24. A support according to Claim 22 where eventually dependant upon Claim 15 wherein the flanges which overlie said oppositely facing surfaces of the first member, diverge away from said surfaces.

25. A pipe support substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

26. Any novel feature or novel combination of features described herein and/or illustrated in the accompanying drawings.