Snubbers & Restraints Metric

Transcription

1 Snubbers & Restraints Metric

2 contents Introduction... 1 Overview... 3 Snubbers (kgf)...7 Rigid Struts (kgf)... 8 Welding Clevis (kgf)... 9 Clamps (kgf) Riser Clamps (kgf) Spreader Beams (kgf) Stiffness and Permissable Loads graphs (kgf) Snubbers (kn) Rigid Struts (kn) Welding Clevis (kn) Clamps (kn) Riser Clamps (kn) Spreader Beams (kn) Stiffness and Permissable Loads graphs (kn) Global Locations...123

3 DYNAMIC RESTRAINTS In pipework systems that are subject to dynamic loading, it may be necessary to use rigid struts, which act in both directions, rather than hanger rods, which only support downward acting loads. Rigid struts are also used to provide lateral restraint where this is required. Snubbers are used where dynamic restraint is required, but the pipe has to be allowed to move thermally.

4 DYNAMIC RESTRAINTS Introduction At Bergen Supports we continually strive to meet the needs of our customers and the latest development in our range of hydraulic snubbers brings about some significant benefits. With over 40 years experience of manufacturing hydraulic snubbers contributing to the evolution of this new model we are able to offer a world-class product to our global market. The new hydraulic snubber is presented in a compact, symmetrical envelope with an integral, pressurised fluid reservoir that means they can be installed in any orientation. The use of corrosion resistant materials means that snubber bodies no longer need to be painted and installation in harsh environments is less of a concern than before. Key features of the SNC range of snubbers are Compact, robust and corrosion resistant Internal, pressurised fluid reservoir Interchangeable with other manufacturers units Maintenance free, precision rod-end bearings Satisfies the key performance requirements of KTA Annex D, BSEN and MSS SP-58. By integrating the fluid reservoir within the length of the main cylinder we have considerably reduced the overall length of the snubber and the redefined range of sizes means that this unit will fit within the same space as some of our main competitors units. We offer nine cylinder sizes giving load capacities of up to 1000kN with strokes of up to 300mm. 1

5 Cyclic test on a 1000kN snubber at 5Hz Load (kn) Displacement DYNAMIC RESTRAINTS Lock-Up Characteristics 3 Load (kn) Displacement Time (seconds) 1 2

6 DYNAMIC RESTRAINTS 3 Overview work systems which are subject to purely static loading are generally supported on single acting vertical supports such as a hanger rod and pipe clamp, sliding base or other rigid type of support. Where the piping is subject to change in temperature then some or all of these vertical supports may be spring supports, either variable or constant effort type. Dynamic restraint of the pipework should a generally cannot be provided by the same system that carries the dead-weight of the piping. Dynamic loading may occur for a number of reasons. Unsteady flow, such as that caused by valve closure, produces dynamic forces and is referred to as water hammer. In an earthquake, a piping system is also subject to dynamic forces. Where the pipework system is subject to dynamic forces, vibration of the pipework will occur. This may be injurious to the pipework, connected equipment and plant. work systems which are supported on single acting vertical restraints and springs with no lateral restraint will have low natural frequencies of vibration and will experience large dynamic deflections when subject to vibration; this will generally be unacceptable. work stress analysis either by response spectrum or time history analysis can be used to show the need for dynamic restraints. In pipework systems which are subject to dynamic loading, it may be necessary to use rigid struts which act in both directions, rather than hanger rods, which only support downward acting loads. Rigid struts are also used to provide lateral restraint where this is required. Snubbers are used where dynamic restraint is required, but the pipe has to be allowed to move thermally. RIGID STRUT IGURE STR Supports Group manufacture a comprehensive range of rigid struts covering loading up to more than 90 tonnes with lengths up to 6 metres (12 8 ). The struts are designed for ease of use and to provide a cost-effective dynamic restraint. Rigid struts use spherical bearings to permit angulation and they provide length adjustment of +/- 100mm (4 ) by means of right and left hand threaded rod ends so that the adjustment can be made without disconnection. Maximum loadings are tabulated in kilograms, Newtons and pounds and weights and axial stiffnesses are also given. Having selected the size of strut that you need, the numbering system used makes the selection of the associated welding clevis and clamp a simple matter. WELDING CLEVIS IGURE WCL The welding clevis provides means of attachment of rigid struts and snubbers to steelwork. The welding clevis is designed to provide +/- 5 degrees of lateral angulation across the pin connection and +/- 90 degrees of angulation around the pin connection as shown below. Direction of Loading 10 SNUBBER IGURE SNC Supports Group s range of hydraulic snubbers cover loadings up to more than 90 tonnes with cylinder stroke up to 300mm (12 ). The part numbering system and sizes of end fittings are compatible with the other dynamic restraint components. Where it is necessary to extend the snubber to suit particular installation constraints we provide the snubber extension tube igure SNE which provides overall pin-to-pin length adjustment of +/- 50 mm. The igure SNC snubber is not provided with length adjustment, fine setting is done by simply adjusting the set position of the piston rod by extending or retracting it. Such adjustment should be limited to +/- 10mm. The hydraulic snubber is a standard 3000 psi hydraulic cylinder with a built-in fluid reservoir. The fluid is ported via the end block to the concentric reservoir. The reservoir acts as a compensator for volume variance & provides long-term fluid replenishment for the small, essential consumption of fluid necessary to lubricate the bearings & seals. In operation, normal thermal expansion of the pipework causes the piston rod to extend or retract at a velocity less than the lock-up velocity. In this situation the snubber is inactive and the device has minimal effect on the behaviour of the pipework. In a dynamic situation, shock or vibration forces which cause the rate of displacement of the piston to exceed the lock-up velocity will cause the regulating valves to close and the snubber limits the velocity. The resistive capacity of the unit transfers the force to the structure and reduces the possibility of overstressing the pipe or associated equipment connections. While the snubber is locked there is a by-pass path through which the fluid can pass at a very low rate. This is essential to allow the pipe to contract as it cools should the plant be shut-down during a seismic event. Where resistance to prolonged thrust is required such as around pressure relief valves, the by-pass is eliminated & the snubber transforms into a rigid restraint once it has been activated. When the force decays the valves open & the snubber once again becomes passive.

7 CLAMPS OR RIGID STRUTS AND SNUBBERS IGURES 521, 522, 523 & 524 Supports Group offer a very comprehensive range of clamps for rigid struts and Snubbers. The igure 521 & 522 clamps are both single plate stiff clamps incorporating a sheathed U-bolt or pair of U-bolts. The igure 523 & 524 clamps are both double-plate stiff clamps, again incorporating a single or double sheathed U-bolt and having the axis of the connecting pin parallel to the axis of the pipe. All four types of clamps use close tolerance load pins and are designed to operate within a 10 (degree) cone of load application. The clamps are designed in four temperature ranges to suit maximum design temperatures of 400 C (752 ), 490 C (914 ), 530 C (986 ), and 570 C (1058 ). Maximum loadings and pin sizes are compatible with those for the struts and snubbers. SELECTION SNUBBERS Determine the minimum required stroke by taking the anticipated design movement and adding an allowance for excess travel. This allowance should normally be at least 20% of the anticipated design movement but not less than 25mm. Then select a snubber where the cylinder stroke is greater than or equal to the minimum required stroke and the applied loadings in tension and compression are less than the allowable maximum loadings in tension and compression for the size and length of snubber as shown in the catalogue. or intermediate lengths, allowable compressive loadings may be determined by interpolation. The length of the snubber must be such that the maximum angulation is not exceeded. To calculate the required closed centres for the snubber, use the following formulae: Closed Centres = Installed Centres X Where X = (Stroke - Design Movement in Extension) / 2 or X = (Stroke + Design Movement in Compression) / 2 This method will result in the spare travel being distributed evenly on either side of the design movement. SELECTION WELDING CLEVIS Welding clevises are selected to suit the size of strut or snubber: e.g. for rigid strut ig or snubber ig , use welding clevis ig DYNAMIC RESTRAINTS TANDEM/RISER CLAMP OR RIGID STRUTS AND SNUBBERS IGURE 525 In situations where it is necessary to restrain the pipe in its axis using a pair of struts or snubbers the igure 525 Tandem/Riser Clamp should be used. This is available to suit four temperature ranges like the stiff-clamps. SELECTION RIGID STRUTS Rigid struts are selected on the basis of maximum applied load and length between pin centres. The loading shown in the table is the maximum applicable for the size of strut in question. A reduced safe working load is shown for sizes C to J at a corresponding increased length. Between the normal maximum length & the increased maximum length linear interpolation shall be applied to derive the actual safe working load. or example. Selection is STR-D with pin-to-pin length L of 3500mm. Safe working load at 3000mm is 46kN Safe working load at 4000mm is 27kN Safe working load at 3500mm is calculated as 46 {(46-27)/1000 x 500} Therefore safe working load at 3500mm is 36.5kN Do not specify strut sizes where the length exceeds that given in the table. If a minimum stiffness of rigid strut is required, make reference to the tabulation of stiffness. The lengths of rigid struts should be such that the maximum angulation is not exceeded, the attachment can be offset on installation if necessary to help achieve this. SELECTION PIPE CLAMP OR RIGID STRUT AND SNUBBER 1) ind the page relating to the appropriate pipe size. 2) ind the section relating to clamp maximum temperature just greater than or equal to the pipework temperature. 3) Look at the clamp part numbers; the number after the pipe size is the clamp load designation which corresponds to the strut or snubber size; e.g. for 150 NB pipe at 500 ºC and using rigid strut size C, choice of clamps is: igure C1-500 or igure C2-500 The choice between C1 & C2 will depend on the specified loading. Higher material grades could also be selected though these would be uneconomic unless material compatibility with the pipe is required. STANDARD EATURES RIGID STRUT 1) A choice of nine standard sizes. 2) Length adjustment of +/- 100mm without disconnection. 3) Sight holes to check thread engagement. 4) Painted finish one coat of high-build acrylic primer with threaded parts electro-zinc plated. 5) +/- 5 degrees permissible angulation. OPTIONAL EATURES RIGID STRUT 1) Painted in accordance with customer s own specification. Threaded parts electro-zinc plated. STANDARD EATURES WELDING CLEVIS 1) +/- 5 degrees and +/- 90 degrees permissible angulation as shown. 2) Painted finish one coat of zinc phosphate primer. 3) Designed to suit maximum strut and snubber loadings. 4

8 DYNAMIC RESTRAINTS STANDARD EATURES HYDRAULIC SNUBBER 1) Offers little resistance to normal thermal movement. 2) Compact furnished as a complete functional unit. 3) Can be used in compression or in tension. 4) Has a built-in reservoir with a transparent window for viewing fluid level. 5) Internal pressurised reservoir, can be installed in any orientation. 6) Units have special fluid and seals suitable for installation in radiation areas. 7) Assessment of travel position by external travel scale machined on to cylinder. 8) Manufactured from stainless steel & non-ferrous metals highly corrosion resistant. 9) Shrouded piston rod. STANDARD EATURES CLAMPS 1) Cost-effective designs to suit the standard strut and snubber sizes. 2) Choice of three styles of clamp. 3) Loading within a 10 degree cone of application of force. 4) Standard finish self colour. HYDRAULIC SNUBBER Specify part number, installed pin to pin dimension and design movement in tension or compression. Specify whether the loading is dynamic bi-directional, e.g. seismic or water hammer, or sustained unidirectional, e.g. relief valve discharge. PIPE CLAMP OR RIGID STRUT AND SNUBBER Specify part number. If applicable, specify any optional features. SPECIAL ITEMS In addition to the range of standard items shown in this catalogue, we design and manufacture dynamic restraints for applications not covered by the standard designs shown. Examples of special items are: 1) Stainless steel clamps. 2) Clamps for rigid struts with inclined loading. 3) Double clamps. OPTIONAL EATURES CLAMPS 1) Hot dipped galvanized finish. 2) Corrosion resistant paint finish. 3) High temperature paint finish. ORDERING INORMATION: RIGID STRUT Specify part number and pin to pin dimension. If applicable, specify any optional features. WELDING CLEVIS Specify part number. If applicable, specify any optional features. 5

9 MATERIAL SPECIICATIONS CLAMPS OR RIGID STRUTS AND SNUBBERS Clamps for use up to 400 ºC Item Clamp Body Clamp Bolts U-Bolt Nuts Pin Spacers (Clamp) Spacers (Pin) Clamps for use in the Range 400 ºC to 530 ºC Item Clamp Body Clamp Bolts U-Bolt Nuts Pin Spacers (Clamp) Spacers (Pin) UK Material BS EN10025 Grade S275JR BS 4190 Grade 4.6 BS EN10025 Grade S275JR BS 4190 Grade 4 BS 970 Grade 709M40 T BS 1387 BS 970 Grade 230M07 UK Material BS EN Grade 13CrMo4-5 BS 4882 Grade B16 BS EN Grade 13CrMo4-5 BS 4882 Grade 4 Pin BS 970 Grade 709M40 T BS 3604 Grade BS 970 Grade 230M07 US Material ASTM A36 ASTM A307 Grade B ASTM A36 ASTM A563 Grade A ASTM A193 Grade B7 ASTM A106 Grade B AISI 1213 US Material ASTM A387 Grade 12 Class 2 ASTM A193 Grade B16 ASTM A182 Grade 12 Class 2 ASTM A194 Grade 4 ASTM A193 Grade B7 ASTM A335 Grade P12 AISI 1213 DYNAMIC RESTRAINTS Clamps for use in the Range 530 ºC to 570 ºC Item Clamp Body Clamp Bolts U-Bolt Nuts Pin Spacers (Clamp) Spacers (Pin) UK Material BS EN Grade 10CrMo9-10 BS 4882 Grade B16 BS EN Grade 13 CrMo4-5 BS 4882 Grade 4 BS 970 Grade 709M40 T BS 3604 Grade BS 970 Grade 230M07 US Material ASTM A387 Grade 22 Class 2 ASTM A193 Grade B16 ASTM A182 Grade 12 Class 2 ASTM A194 Grade 4 ASTM A193 Grade B7 ASTM A335 Grade P12 AISI 1213 Detailed erection and maintenance procedures for rigid struts and hydraulic snubbers are available on request. 6

10 DYNAMIC RESTRAINTS Snubbers (kgf) Size Stroke Basic Load (kgf) ød Pin S 22 ød Snubber Pin-to-Pin at Mid-Stroke Snubber without Extension E Min E Max E Min +/-50 Adjustment Snubber with extension E Min +/-25 Adjustment E Max 1 A B R G H without Extension (Kg) SNC-A SNC-B SNC-B SNC-C SNC-C SNC-D SNC-D SNC-E SNC-E SNC SNC SNC-G SNC-G SNC-H SNC-H SNC-J SNC-J Snubber lengths greater than EMax are possible, with a reduced compression load capacity. 2 Spherical bearing width 7

11 Dimensions, Load Capacities and s of Rigid Struts (kgf) DYNAMIC RESTRAINTS Type Basic Load L Adjustment L (Min) L* (Min) L (Max) L(Max) Reduce Load Reduced Load for L(Min) Increased Ød Pin ØD Strut R B kgf mm mm mm mm mm kgf kg kg/ 100mm mm mm mm mm STR-A / STR-B / STR-C / STR-D / STR-E / STR / STR-G / STR-H / STR-J / * or reduced adjustment of ±25mm or graphs of Stiffness and Permissable Loads for Rigid Struts (kgf) please refer to page 64. 8

12 DYNAMIC RESTRAINTS Dimensions, Load Capacities and s of Welding Clevis (kgf) Type Max. Load Pin ØA 1 E1 R B A kgf mm mm mm mm mm mm kg WCL-A WCL-B WCL-C WCL-D WCL-E WCL WCL-G WCL-H WCL-J

13 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 1 /25mm mm C C C C C C C C C C mm mm mm mm mm mm kgf A A A A DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) NB 1.25 /32mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf B A B A A A Clamps for Rigid Struts and Snubbers (kgf) NB 1.5 /40mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf B A B A A A

14 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 2 /50mm mm C C C C C C C C C C mm mm mm mm mm mm kgf C B A B A B A B A Clamps for Rigid Struts and Snubbers (kgf) NB 2.5 /65mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf C B A B A B A B A Clamps for Rigid Struts and Snubbers (kgf) NB 3 /80mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A C B A C B A C B A

15 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 3.5 /90mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A C B A C B A C B A DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) NB 4 /100mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A C B A D C C B A D C C B A D C

16 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 5 /125mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A C B A E D C C B A D C B C B A D C B

17 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 6 /150mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A E D C B A D C E D C B A C B A E D C C B A C B A E D C DYNAMIC RESTRAINTS 14

18 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 7 /175mm mm C C C C C C C C C C mm mm mm mm mm mm kgf E D C B A E D D C B A E D E D C B A D C E D C B A D C E D

19 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 8 /200mm mm C C C C C C C C C C mm mm mm mm mm mm kgf E D C B A E D D C B A E D E D C B A D C E D C B A D C E D DYNAMIC RESTRAINTS 16

20 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 9 /225mm mm C C C C C C C C C C mm mm mm mm mm mm kgf E D C B A E D D C B A E D E D E C B A D C E D E D C B A D C E D E D

21 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 10 /250mm mm C C C C C C C C C C mm mm mm mm mm mm kgf E D C B A E D E E D C B A E D E D E C B A D C E D E D C B A D C E D E D DYNAMIC RESTRAINTS 18

22 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 12 /300mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A E D E E D C B A E D E D E E C B A D C E D E D E C B A D C E D E D E

23 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 14 /350mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A E D E E D C B A E D E D E E C B A D C E D E D E C B A D C E D E D E DYNAMIC RESTRAINTS 20

24 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 16 /400mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A E D E D E G D C B A E D E D E E G C B A D C E D E D E G E C B A D C E D E D E G E

25 Clamps for Rigid Struts and Snubbers (kgf) Type 523 Clamp Load Capacity (kgf) at erature C Type 524 Clamp NB 18 /450mm mm C C C C C C C C C C mm mm mm mm mm mm kgf D C B A E D E E G D C B A E D E D E E G C B A D C E D C E D E D G E H G C B A D C E D C E D DYNAMIC RESTRAINTS 22

26 DYNAMIC RESTRAINTS Clamps for Rigid Struts and Snubbers (kgf) Type 521 Clamp Load Capacity (kgf) at erature C Type 522 Clamp NB 18 /450mm mm C C C C C C C C C C mm mm mm mm mm mm kgf E D G E H G Clamps for Rigid Struts and Snubbers (kgf) NB 20 /500mm Load Capacity (kgf) at erature C mm C C C C C C C C C C mm mm mm mm mm mm kgf E D C B A E D G E H G H G E D C B A E E G G G H G E D C