Patent GB-647121-A (GB)
Title: Resilient supporting or steadying devices for piping
IPC: F16L3/205
Filed: 1945-05-02
Abstract: 647,121. Supporting pipes. WARREN, S. F. (General Spring Corporation). May 2, 1945. Nos. 11076/45, 1450/46 and 1451/46 [A Specification was laid open to inspection under- Sect. 91 of the Acts, Oct. 15, 1945] [Class 99(ii)] [Also in Group XXXII] A spring supporting or steadying device for piping systems which allows relative movement between the piping and a support while preventing harmonic vibration of the piping, has connections respectively to the piping and to the fixed support from spring means in the device arranged for elastic deflection and recovery upon movement of the piping in opposite directions through and beyond its normal operating position under the action of alternating or intermittent forces, the deflection of the spring means being positively limited in one direction at a single pre-determined mid point which corresponds to the normal operating position, and the spring means being prevented from overshooting the mid point when going out of action. In the construction shown in Fig. 2 a single spring 22 is mounted in a tube 2 between abutment washers 20 each slidable on a tubular portion 12 of a respective piston 14. An annular ring 18 of frusto-conical profile is slidably mounted on each tube 12 and cooperates with a segmental friction ring 16. Outward movement of each piston 14 in the tube 2 is limited by end-plates 4, 6 welded to the tube 2 and neoprene &c. cushioning washers 24. A piston rod 28 has an abutment in the form of a nut 30 welded to its inner end which engages through rigid and resilient washers 32, 34, a shoulder 26 formed within the upper tube 12. A shoulder 37 on the piston rod 28 similarly engages the lower piston assembly. A bronze or self-lubricating bearing bush 46 guides the outer end of the pistonrod 28 which carries an adjustable threaded eye 48. The spring 22 may be pre-loaded but the eye 48 is adjusted so that both pistons seat on their respective abutments when the load or member to be supported is in its normal operating position. In the construction shown in Fig. 18, a tubular housing 56 has a gland 94 at its lower end for a piston rod 76<SP>1</SP> connected to the load or to the support at its outer end and carrying an integral frusto-conical shaped piston head 81 and integral cylindrical spigot 76" at its inner end. A frustoconical-shaped ring 88 is slidably mounted on the spigot 76" and co-operates with the head 81 to expand a segmental friction ring 84 into engagement with the inner wall of the housing 56 under the action of a compression spring 72 bearing on the ring 88 and a tension spring 70 pulling on the spigot 76<SP>1</SP>. The other end of the spring 72 bears on a plug 60 rigid with the upper end of the housing 56 and the other end of the spring 70 is secured to a spindle 76 threaded for axial adjustment in the plug 60 relative to an indicator scale 206. The housing may contain oil charged through a nipple 210 to provide liquid damping by flow past the piston assembly or alternatively through passages (not shown) provided in the assembly. Air trapped in the housing may provide additional cushioning. The springs 70, 72 (as shown) have deflection rates which vary along their lengths, and the outer ends of the spring 70 may be under initial stress before any deflection of the spring occurs. The segments of the friction' ring 84 may be of phosphor bronze and are united by a ring 86. In operation, the spindle 76 is adjusted so that the loads in the springs 70, 72 balance one another when the member to be supported is in its normal operative position. In the construction shown in Fig. 4, two springs 23, 22a which may be identical or may have different rates, are mounted in a tube 2a between upper and lower outer abutment discs 4a and inner abutment discs 20a. A piston 32a slidably mounted in a tube 12a rigidly secured to the tube 2a by welded discs 82, is connected to the supported member by a piston rod 3a, deflection of which above or below the normal operating position shown thus loads the spring 23 or the spring 22a respectively. The action is cushioned by resilient washers 24a, 34a and adjustment of the springs 23, 22a may be effected by rotation of a gland 7a and studs 62 respectively, in conjunction with an indicator 52 and pointer-disc 53. In an alternative mounting for the piston 30 (Fig. 5 not shown) the tube 12a may be resiliently mounted in the tube 2a by an assembly of annular rubber washers. A liner of antifriction metal may be provided between the piston 32a and the tube 12a. In a construction of piping sway-brace (Fig. 7, not shown) two tension springs are arranged horizontally in opposed relation between respective turn-buckle connection to I-section beams and respective headed stems, integral with a lug welded to the pipe. The stems slidably engage plugs carried by the respective ends of the spring so that for deflection of the pipe in one direction from the normal position, one of the stems slides freely through its plug while the head of the other stem engages its plug and deflects the respective spring. The springs, which may have different rates, may or may not be preloaded in the normal position in which they are both un-deflected. In a further construction (Fig: 8, not shown), two tension springs are screwed at their outer ends on to plugs having apertured load-connecting lugs, and at their inner ends to a common plug. A stem extends through the inner, and one of the outer plugs, is secured to one of them and is slidable within the other, the extent of displacement being limited by a head on the stem. On displacement of the load from the relaxed position of the spring-unit, both sections of the spring are extended until the stem head engages its respective plug to prevent further deflection of the section of the spring between the plugs through which the stem passes. The sections of the spring may be formed by separate springs united by the common plug. The non-limited section of the spring may be stronger than the other section and may be pre-stressed so that it does not come into action until the stem head is engaged. In the construction shown in Fig. 10, a tension spring 23g is secured to one end of a tube 2g connected to the piping or to the support at 8g and which also contains a compression spring 22g in abutment with the other end of the tube 2g and a piston 89g connected to the support or to the piping, by a piston rod 28g. An extension of the rod 28g extends slidably through a plug 104g secured to the inner end of the tension spring 23g. On deflection above the normal operating position (shown), the spring 23g remains un-denected. The spring 23g may be pre-loaded in its un-deflected condition. In a similar construction (Fig. 11, not shown) the arrangement is modified so that the tension spring is in operation for deflections above and below the normal position while the compression spring operates only for deflections below. In a further construction (Fig. 9, not shown), tension and compression springs are connected in series so that both springs operate for deflections in one direction while the compression spring ceases to operate on deflection in the other direction from the normal position due to solid engagement of its coils. In a similar construction (Fig. 6, not shown), both springs are compression springs and either spring may be arranged to become solid at the normal position or alternatively either spring may be made ment between the two springs coming into non-operative at this position by the abutengagement with the other abutment of the respective spring. In the construction shown in Fig. 17, a tubular housing 2j secured to a pipe-supporting beam B, contains a main spring 22j and a weaker spring 23j. An inner tubular member 11j is rigid with a support member by a spindle 8j. The main spring 22J acts between an end plate 6j rigid with the housing 2j and an abutment 14j welded to the tube 11j. The spring 23j acts between an abutment 26j also welded to the tube 11j, and a washer 4j which is engaged by a member 7j rigid with the housing 2j. The downward deflection of the washer 4j is however limited by an annular abutment 160j welded to the tubular member 11j. A pipe (Fig 16, not shown) is supported centrally of the beam, each end of which is suspended from a respective channel-shaped support member by the spring unit of Fig. 17. The pipe may be connected upwardly or downwardly to a fixed point by a vertically-disposed rigid member which deflects the pipe as it expands in attaining working temperature from a cold condition. By this arrangement the springs 22j, 23j, are so loaded that the spring 23j is just at the point of going out of action in the normal operating position of the pipe at working temperature. In the constructions described which have a tubular housing, oil in the housing may provide a dashpot action in a similar manner for example as described in Specification 565,186.