More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Engineered Spring Support Webinar - January
Similar to Engineered Spring Support Webinar - January (20)
More from Piping Technology & Products, Inc.
More from Piping Technology & Products, Inc. (15)
Engineered Spring Support Webinar - January
- 1. Piping Technology & Products, Inc. Engineered Spring Supports Presents
- 2. PT&P and Subsidiaries Fronek Anchor Darling Ent., Inc. ASME Nuclear Qualified Pipe Shields, Inc. ISO 9001-2000 Certified Sweco Fab, Inc. ASME U-Stamp R-Stamp PIPING TECHNOLOGY & PRODUCTS, INC. Member of MSS, SPED, APFA, U.S. Bellows, Inc. Member of EJMA
- 3. Engineered Spring Supports Types Constant Spring Supports Big Ton Springs Variable Spring Supports
- 4. Engineered Spring Supports Types Figure 1 Variable Spring Support Figure 2 Variable Spring Hanger Figure 3 Constant Load Hanger
- 11. Spring Loading/Assembly Check Hot & Cold Loads Compress Spring to Solid and Release 3 Times Zero out Load Cell Compress Spring to Cold Load Mark Cold Location on Can Measure for Travel Stop Length Compress Spring to Hot Load
- 12. Spring Loading/Assembly Mark Hot Location on Can Measure Distance Between Loads Should Match Desired Travel Compress Spring to Cold Load & Place in Travel Stops Release Load and Check Travel Stops Remove Spring & Move to Table Using Hoist
- 13. Spring Loading/Assembly Add Name Tag and Straps Drill & Hammer Rivets into Place Measure the Remaining Slot for Hydro-Test Stops Put Stops in Place & Strap Them Down Last Step: Measure and Adjust Load Flange Height if Necessary
- 14. Big Ton Spring Supports
- 15. Constant Spring Supports Introduction Fig. 200 U-Type Constants Fig. 200 Type-U, Upthrust Constants Designed for an Exceptionally Large Travel
- 18. Constant Spring Supports Base Type Fig. 200 U-Type Upthrust Constant Fig. 100 U-Type Upthrust Constant F-Type Constants
- 19. Constant Spring Supports Upthrust U-Type Upthrust Constants Ball Transfer Units
- 26. Useful Life of a Spring Hanger Average life expectancy of: 10 years 20 years 30 years Unprotected Spring Hanger Galvanized Hardware Neoprene Coated Springs
- 29. Field Examples/Tips No load indicator
- 30. Field Examples/Tips 2 x 4 still under pipe Not Set correctly
- 31. Field Examples/Tips Slide plate not attached to load flange Out of adjustment Still has a travel stop
- 32. Field Examples Corroded cans should be replaced Cans are not supporting load
Editor's Notes
- For those of you who are unfamiliar with PT&P, I want to quickly go over some background information. If you would like to know more, please visit our “About Us” section at pipingtech.com. Our parent company, Piping Technology & Products, Inc., also known as PT&P, is a member of MSS, SPED, and APFA In business since 1975, Piping Technology & Products, Inc. and its wholly owned subsidiaries (US Bellows, Sweco Fab, Pipe Shields, and Anchor Darling) offer a wide range of engineered products and services for various industries and applications. Our product line is extensive… From engineered pipe supports, expansion joints, pre-insulated pipe supports, and miscellaneous fabrication to various engineering and technical services, PT&P has decades of experience providing products and services for all your engineering and construction needs.
- The main purpose of an engineered spring support is two-fold: 1.) To uphold a specific load, including the weight of the pipe, commodity, flanges, valves, refractory, insulation, etc. AND 2.) To allow the supported load to travel through a predetermined thermal deflection cycle from its installed condition to its operational condition. A few types of engineered spring supports are shown here: Variable spring supports are used where: 1.) Relatively small thermal deflections, usually less than or equal to two inches (2 " ) are anticipated. AND 2.) A difference in the supported load from the installed to the operating condition is acceptable. We carry a substantial amount of variable springs in our inventory which can accommodate loads up to five-thousand pounds (5,000 lb.) “ Big ton” springs are used for very large load conditions where standard variable springs are too small. Constant spring supports are utilized when: 1.) The supported load cannot vary between the installed and operating position. AND/OR 2.) Large thermal growth is anticipated.
- Figure 1 is a variable spring support designed to support piping from below, directly from the floor or supporting steel. Adjustment is made by inserting a bar into holes in the load column and turning the load column as a jack screw. The base plate is bolted to the case and has four holes for fastening. Figure 2 is a variable spring hanger designed to support piping from above. Figure 3 shows a constant load hanger which is typically used to support piping subject to vertical movement.
- Variables use coiled springs to support a load and allow movement The resistance of the coil to a load changes during compression, which is why these devices are called “variables” There are many different designs for variable supports, we use A through G to describe seven different physical connections to the supporting structure. A-E and G are hangers suspended from structural members and type-F is a base support that rest on the supporting surface. All our variables are available in short springs, standard springs, double springs, triple springs or quadruple springs.
- Type A variable spring supports are furnished with a threaded bushing in the top plate, providing for a simple rod attachment for the upper connection.
- Types B and C variables are furnished with one or two lugs welded to the top cap plate of the casting.
- Type D variable permits adjustment from the top, by turning the nuts on the hanger rod against the load column which protrudes through the top. Type E variable spring permits rod adjustment from either above or below the spring. This type of spring can be set above the supporting steel.
- Type F is designed to support piping from below, directly from the floor or supporting steel. The base plate is bolted to the case and has four slots for fastening. An interesting feature of F-type variables is that the installed height can be adjusted independently of any load adjustment.
- A type G spring support assembly is formed by welding two standard spring assemblies to the ends of a pair of channels. This type of variable can accommodate unusually heavy loads and is adaptable for avoiding interference in spaces where headroom is limited. Travel stops are inserted and strapped in place to maintain the load for the assembly installation. The “g-can” pictured here was manufactured for a Petrochemical Plant. As a side note, you may notice that the travel stops have been chained to the spring housing. This is an optional feature available on all spring supports which prevents loss of the travel stops after the assembly is put into service.
- For the next three slides, we will go through the steps in loading a spring can. This particular spring can has a cut-away view for demonstration purposes. The first step is to check the hot and cold loads on the assembly drawing. The second step is to compress the spring to solid and release three times total. Then you will need to zero out the load cell before you compress the spring to the specified cold load. Mark the cold load location on the can, then measure for the travel stop length. Next you will need to compress the spring to the specified hot load.
- Mark the hot location on the spring can, then measure the distance between load. The distance should match the desired travel. Compress the spring to the cold load and place the travel stops in. Release the load and check the travel stops. Remove the spring from the cage to a table using a hoist.
- When adding the name tag and straps, first you need to drill and hammer the rivets into place. Measure the remaining slot for hydro-test stops Put the stops in place, strap them down, measure and lastly, adjust the load flange height if necessary.
- Big ton springs are custom designed to meet load and travel requirements for very large loads using a multiple coil system. Usually a base-mounted support that can be designed with slide plates for lateral pipe movement. The height, width and length are also custom designed to meet space requirements.
- Now lets switch gears and learn more about PT&P’s constant spring supports. Constants are used when the load variability between the hot and cold loads exceed 25%, and/or around sensitive rotating equipment where a load variation could be harmful. The constants pictured on the left are fabricated from A36 carbon steel and designed to handle a load of twenty-four thousand pounds. These particular constants are capable of three (3) inches of total upward travel. The large constant pictured on the right was designed for a geothermal plant and measures twelve feet in length and four feet in height. The customer required the constant load to be twenty-five hundred pounds and forty-six inches of travel.
- Horizontal constants are used mostly when vertical space is not available; the spring can is aligned horizontally, while permitting vertical movements. The drawing on the left is a figure 200 A-type constant. This type of support is useful where the rod take-out is small and will be bolted directly under the beam eliminating the space used up by the mounting lugs. Pictured on the right is a PT&P figure 200 B-type constant.
- Vertical constants are used mainly when horizontal space is not available. Pictured on the right is a PT&P figure 100 B-type vertical constant. Notice the use of double-pin suspension instead of single-point suspension. This will eliminate any constant rotation as the pipe moves due to thermal expansion.
- Pictured here are U-type upthrust constants designed to handle 6" of total travel and loads of 5,677 lb. and 4,956 lb. The load flange is modified to hold six ball transfer units for each support. The ball transfer units are used to decrease the coefficient of friction to 0.05 compared to using the standard PTFE, 25% glass filled, which is 0.15. Gussets are added under the load flange to maintain a leveled surface and an equal load transfer to all ball transfer units. These custom designed constant supports are manufactured for steam power plant superheaters.
- Pipe Hangers are designed to control: Longitudinal weight stress in the piping system without creating additional stresses Piping system loads on equipment without limiting or reducing static loads Hanger loads on building structure And physical clearances of hanger components with piping and structure Let’s look at the basic steps in the hanger design: Step 1 is to determine the location of all the hangers Then calculate the hanger loads due to the piping weight Next calculate the thermal movement of the piping at each hangers location Step 4 is to select the hanger type and finally check all clearances
- While installing, securely attach the spring to the existing structure per the spring support design.
- If required, attach a hanger rod to the fabricated load column or turnbuckle.
- Next attach other related hardware, for example, here is a constant in the field with the rod, turnbuckle, weldless eye nut and welded beam attachment.
- After hydro-testing, remove the travel stops as pictured here.
- And the last step in installation is to verify that the load indicator is at the desired setting (cold/hot load)
- Let’s look at the average life expectancy of a spring hanger: An unprotected spring hanger will last anywhere between fifteen (15) and twenty (20) years. If the hardware is galvanized, which is PT&P’s standard, the spring hanger will last between fifteen (15) and thirty (30) years. And if the springs are coated with Neoprene, it will last fifteen (15) to thirty (30) years. Corrosion and fatigue are the main factors that contribute to the deterioration of a spring hanger assembly.
- If the piping system has inadequate support, static loads can cause multiple problems, like: Leaking flanges Pump and turbine problems, mainly concerning the bearings, seals and misalignment of flanges Sagging lines and/or liquid trapped in low sections And an increase in system stresses can result in piping failures as well
- When inspecting a spring support, the first thing you want to do is: Visually inspect each spring hanger in accordance with the ten point operational integrity check which is pictured here. After the ten-point visual inspection, you should tag each spring hanger as good, adjust, or replace then issue a field summary report.
- Pictured here are non-PT&P supports our field service technicians found in the field. Notice in both examples, the load indicator scales are missing or painted over. While it can be stated that the supports are taking load, it is extremely difficult for field personnel to distinguish the precise load these assemblies are holding.
- Notice here on the left, the setting on this variable spring is incorrect by the load indicator label to the right of the spring. And on the right pictures a two-by-four left under the pipe.
- Again, this support on the left is out of adjustment and the slide plate is no longer attached to the load flange. Note that these supports are not fabricated by PT&P. Pictured on the right is a C-Type variable spring support with the travel stop left in. Failure to remove the travel stops would lock the spring coil in position and render the support inoperable.
- The above examples are indicative of supports which show limited functionality. The pair of base-type springs on the left exhibit significant rusting of the spring coil. Extensive deterioration of the coils would alter the spring rate and ultimately reduce the load carrying capability of the assembly. The two examples on the right show variable spring assemblies which have not been loaded. The load indicator at the top of the slot is a clear indication that either 1.) the springs have been unloaded and never returned to service or 2.) the assemblies were improperly sized for the load.
- When deciding on whether to replace a spring can or not, consider the corrosion, fatigue, rust damage, and the modification of surrounding equipment and piping.
- In the case you want to use your existing spring support, re-calibration is an option as long as the support is a constant spring support, in good operating condition, has an operating load range greater than fifteen thousand (15,000) pounds and the cost of field time and equipment is less than the cost of a new spring hanger.
- To adjust a spring hanger after inspection, set to the desired position by turning the turnbuckles and load column. When the nameplate is present indicating the design hot load, adjustments can be made during operation, but a cold load adjustment needs to be made during a shutdown.
- A few thoughts during shutdown: Are the lines and equipment temporarily supported while repairs are being made? To prevent having to readjust the spring, I need to re-install the travel stops. If the name plate is missing, stencil the proper installed and operating positions or provide loads for re-calibration.
- Remember: When selecting springs, determine the location of the hanger, calculate the hanger load and the thermal movement of the piping at the location. For optimum performance, follow the installation guidelines from attaching the spring to the existing structure to setting the load indicator. When inspecting springs: Utilize the 10 Point Operational Integrity Check to make sure your springs are in good working order. Plan now to replace damaged and/or improperly sized springs that could ultimately lead to catastrophic failure.