Big Ton Spring Supports

Constant Spring Hangers

Expansion Joints

FRP Wear Pads

Pre-Insulated Pipe Supports

Slide Plates

Snubbers

Variable Spring Hangers

Vibration Control Sway Brace

Piping Technology & Products’ constant spring hanger, usually referred to as a constant, provides constant support force for pipes and equipment subjected to vertical movement due to thermal expansion at locations where maintaining a constant stress is critical. This constant resistance is achieved by having two-moment arms pivoted about a common point. The load is suspended from one of these arms, and a spring is attached to the other. With an appropriate choice of moment arms and spring properties, a resisting force can be provided that is nearly independent of position. As with variable springs, Type refers to the connection of the constant to the structure and the pipe. Figure 4 shows the attachment for Types A – E. The designation Figure 100 and 200 refer to the orientation of the spring can. This is vertical for Figure 100, and horizontal for Figure 200.

Travel stops are installed in all constants before shipping. These must be present during installation and any hydro testing, but must be removed before normal operations. They are usually pins, but in some cases may be keys. See note below on travel key removal. In either case, the load must be adjusted so that the travel stop is easily removed.

Caution: Do not force the travel stops.

Figure 4: Constant Hangers Types A – E.

 

Red, White and Blue Marks:

All constants are shipped with at least 3 color-coded rivets (red, white and blue).
Red: operating (HOT) position
White: installation (COLD) position
Blue: over travel (MAX AVAILABLE) position

Below are sketches of one direction vertical travel:

Below is a sketch of dual direction vertical travel:

Types A – E Constants (100 & 200)

Figure 5: Travel stop position.

1. Secure the hanger to a structure capable of handling the operating load, at a point where the constant’s load coupling is directly over the desired point of attachment to the pipe in the operating position.
2. The hanger rod and loading arm of the constant should be unobstructed.
3. Attach the connecting rod to the turnbuckle with full thread engagement.
4. Transfer the load by turning on the turnbuckle before removing the travel stop.
5. If required, hydro testing should be done at this time.
6. Once the load is transferred, the travel stop must be removed. The travel stop (painted red) should now slip out easily. If not, refer to Figure 5. The travel stop pin must be moved to the center of its hole by adjusting the hanger load. The hanger load needs to be increased if the pin is in position A, or decreased if the pin is in position C. Once disengaged, the travel stop may be stored by hanging it from the constant.
7. The hanger load should now be readjusted to the cold (white mark) position.
8. When the operating conditions are reached, check the hanger to assure the indicator is at the hot (red mark) position.

Type F – 100 Constants

Figure 6: F – 200 Type constant, and Travel Stop Pin positions.
1. Secure base plate to the structure.
2. If the constant is of the platform type (see Fig. 6), place the pipe on the platform, and attach it to the platform. If there is no platform, attach a strut to the piping, then to the constant support.
3. Hydro test line if necessary.
4. The travel stop should be in the middle of its hole. If the travel stop is in the A- configuration (see Fig. 5), contract the strut, and if it is in the C- configuration, expand the strut to force the travel stop pin to move to the center of the travel stop hole. When the travel stop pin is centered in the travel stop holes, it can be easily removed and the constant is ready for operation.

Danger!! If pin cannot be easily removed after struts adjustment, do not drive pin out.

Type 200 – F

The Type 200 – F constants are shipped with two installation rods.
1. Attach the base plate of the constant to the supporting structure by placing the constant in its installation location. If the clearance is tight, temporarily force the table down by loosening the 2 travel stop nuts on top of the angles, then tightening the nuts below.
2. Loosen the travel stop nuts below the angles to allow the load flange to rise up to the installed height: 3/8″ max. If the clearance is bigger than 3/8″, shim or grout the constant or pipe attachment accordingly. Re-tighten the 2 travel stop nuts above the angles.
3. Hydro test line if necessary.
4. Loosen and raise up the travel stop nuts above the angles at least a nut thickness to allow the removal of the travel stop rods. Remove the travel stop rods from the load table and store for future use. The constant effort support is now ready for operation.

  Figure 7: Type 200 – F

Type 200 – U (Upthrust) Constants

Figure 8: 200-U Type Constant, and Travel Stop Location1. Attach the base plate of the constant to the supporting structure by placing the constant in its installation location. If the clearance is tight, temporarily force the table down by loosening the four lower travel stop nuts, then tightening the four upper travel stop nuts.
2. Loosen the upper travel stop nuts to allow the load flange to rise up to the installed height: 3/8″ max. If the clearance is bigger than 3/8″, shim or grout the constant or pipe attachment accordingly. Re-tighten the four lower travel stop nuts.
3. Hydro test line if necessary.
4. Back the four lower travel stop nuts all the way down. Back the four upper travel stop nuts all the way up, but do not remove from installation rods. The constant effort support is now ready for operation.

Type G Constant
The Type G constant consists of two Type 100 constants connected by a beam, with the pipe being supported on the beam.
1. Support the pipe at the desired elevation.
2. Attach load rods to the structural support.
3. Attach the constant to the load rods using the turnbuckles provided.
4. Using the turnbuckles, level the pair of channels connecting the two constants.
5. Keeping the channels level, transfer the pipe load to the constant, either by raising the constants or removing any temporary support for the pipe.
6. If hydro testing is required, this should be done now.
7. Remove the travel stops. If they are not in the center of their holes, use the turnbuckles to adjust the load so that the stops are in the center. They should be easily removed. If not, adjust the load until they are.Do not drive them out.
8. Using the turnbuckles, adjust the load indicator to the cold position.
9. After the load reaches normal operating conditions, check to see that the load indicator is at the hot position. If not, adjust with the turnbuckles.

Figure 9: G Type Constant

MAINTENANCE INSTRUCTIONS 

1. Each pipe support should be inspected periodically anywhere from monthly to annually (based on the surrounding environment) to verify load and movement with respect to the design load and travel on the nameplate on the constant frame. 
2. Clean any and all dust and soot that may gather up in the coil housing especially in dusty environments (desert areas, windy location, and around Coker units). 
3. Remove any and all foreign objects and debris (bird nest, fallen objects, and pushed aside objects) that may impair spring coil, hanger rod, or load table movement. 
4. On base type units, ensure the slide plate’s functionality through the absence/removal of dust, soot, and debris on the slide plates that exist between the load flange and the beam/pipe above it. 
5. No greasing or lubrication is required to any of the constant support parts

Field Instructions for Load Adjustment, Fig. 100 & 200
Under no circumstances should an attempt be made to remove the lock nut and the load adjustment nut from the constant spring hanger.

Every constant spring hanger is calibrated in the factory and set to the load specified on the nameplate. Load adjustment in the field is discouraged as it may significantly change the system.

However, to provide for situations where the supported load is different from the calculated load, the constant spring hangers are equipped with load adjustment capability. The load adjustment capability consists of a load adjustment scale and indicator, which are used to increase (Figure 10A) or decrease (Figure 10C), the load by 10%. Thus, a 2000-pound hanger can be adjusted for loads from 1800 to 2200 pounds. The travel stop pin must be engaged before load adjustment is performed. Adjusting the load to higher or lower load from the load specified on the nameplate using load adjustment is approximate and not recommended.

Figure 10: Field adjustment for load. The Load Adjustment Scale is located on the spring can, near the adjustment nut.
To increase the cold setting be sure that the travel stop pin is in place. Then loosen the lock nut at the end of the spring. Tighten the main nut, then retighten the lock nut.

To decrease the cold setting be sure that the travel stoop pin is in place. Then loosen the lock nut at the end of the spring. Loosen the main nut, then retighten the lock nut.

Constant Hangers with Adjustable Travel Stop Keys: Removal of Travel Stop Key

Figure 11: Adjustable Travel Stop Keys
1. After hanger installation, remove the travel stop hex nuts from both sides. Check whether A-face or B-face of the threaded bolt is in constant with the travel stop keyhole as illustrated in Fig 11, above.
2. If the B-face of threaded bolt is in contact with the travel stop keyhole as shown in Figure 11, turn the turnbuckle clockwise. The travel stop bolt will move towards the center. At this point, the load has been transferred and the constant hanger is balanced with the pipe weight. The travel stop key can be easily removed.
3. If the A-face of threaded bolt is in contact with the travel stop keyhole as shown in Figure 11, turn the turnbuckle counterclockwise. The travel stop bolt will move towards the center. At this point, the load has been transferred and the constant hanger is balanced with the pipe weight. The travel stop key can be easily removed.

The vibration control and sway brace is shipped ready for installation.

1. Measure the correct space required to install the sway brace assembly. Lay out the sway brace assembly as it is to be installed. Weld one end of structural attachment to the structure and affix the other end with clamp or bolting as required. Make sure the sway brace is located in the same direction as the thermal movement of the pipe. Tighten the adjustment coupling to release the travel stops if supplied. Turn the thrust nut until the bottom of the pressure plate lines up with the pre-load indicated on the nameplate.

2. The brace should be in the proper configuration when it reaches the hot condition. If not, final adjustments can be made by tightening or loosening the adjustment coupling.
i) When properly adjusted, the rod coupling should rotate with slight resistance and the tension test collar can be rotated by hand while holding the rod stationary. There should not be any gap between either end of the pressure and end plates.
ii) Two rod ends should be visible in the adjustment coupling.

When the system shuts down for maintenance, the travel stops should be reinstalled and the same adjustment procedure should be repeated.

Figure 12: Sway Brace

Clean the pipe following the pipe cleaning procedure explained in Note #2. Clean the pipe for the length of the shoe plus 3 inches on either side of where the shoe will be installed. Put the slide plate on the structural support member and center it on the centerline of the pipe. Remove the slide plate and check the surface of structural support member below for bumps or high points. Remove any that are found. Replace the slide plate and weld the mounting plate to the structural support member as shown. Protect PTFE, 25% glass filled, with duct tape or equivalent during welding. Clean the bottom half of the insulation. For Cold Shoes, the polyurethane should be prepared for bonding by sanding it lightly with 60 grit sandpaper.

For Cold Shoes apply .042 to .080 inches of a wet film thickness of adhesive (Fosters 82-77) to the inside of the insulation, as per manufacturer’s instructions. Slide the assembly under the pipe into position above the slide plate which is mounted on the structural support member (See Note #1 for the desired location). Note that field trimming of the calcium silicate may be required for a proper fit to the pipe circumference. Lower the pipe onto the bottom half of the saddle.

Clean the bottom half of the insulation. For Cold Shoes, the polyurethane should be prepared for bonding by sanding it lightly with 60 grit sandpaper. For Cold Shoes apply .042 to .080 inches of a wet film thickness of adhesive (Fosters 82-77) to the inside of the insulation, as per manufacturer’s instructions. Slide the assembly under the pipe into position above the slide plate which is mounted on the structural support member (See Note #1 for the desired location). Note that field trimming of the calcium silicate may be required for a proper fit to the pipe circumference. Lower the pipe onto the bottom half of the saddle.

Align the clamping holes of the top half to the bottom half of the saddle, and press them together. Seal longitudinal joints and the overlapping ends of the jacket with a suitable sealant such as Foster’s Flextra 95-50 or equivalent. Install the clamping bolts, lock washers and nuts. Hand tighten first, check the alignment of the saddle and position. When found correct; tighten the nuts applying required torque specified in the drawing.

NOTES:

1. Cold Setting:
• For an axial cold setting, position the support assembly such that after the support has moved, the centerline of the slide plate approximately matches the centerline of the support.
• For lateral cold setting, center the support assembly over the slide plate.

2. Pipe Cleaning Procedure:
• The pipe shall be cleaned before the application of the adhesive. Carbon steel pipe should be solvent cleaned and allowed to dry. Stainless steel and high alloy pipes which have been primed shall have the primer roughened with a hand tool or power tool, followed by solvent cleaning.
• When used in cryogenic applications (below –40^oF), the metal surface must be sandblasted or primed with polyamide epoxy primer.

Maintenance & Storage Instructions for Insulated Pipe Supports (Cold Shoes)
1. Do not unpack the cold shoe unless the support is ready to install.
2. Store all cold shoes at a site where the cold shoe components are not exposed to ultraviolet rays.
3. Coat all exposed surfaces of high-density polyurethane foam with monolar mastic in a well-ventilated area.
4. Wrap all cold shoes and Polyurethane bases with black plastic.
5. Protect all cold shoes from outside moisture, especially rainwater.

Recommended Storage – Covered area, preferably warehouse or at minimum, under a tarp, above ground left in original packing until use.

• Installation
• Post Installation Inspection Before Test
• Inspection During and After Test
• Periodic Inservice Inspection
• System Operation
• Typical Causes of Expansion Joint Failure
• Installation Misalignment
• Squirm or Instability

Pipe Expansion Joints: Do’s and Don’ts  From the “Standards of the Expansion Joint Manufacturers Association, Inc”

Refer to EJMA Standard for proper guide spacing and anchor recommendations.
NOTE: The manufacturer’s warranty may be void if improper installation procedures have been used.

There are four different types of slide plates. They are the same except for the slide material. PTFE, 25% Glass Filled is typically used where temperatures are less than 400^o F, and graphite is used at higher temperatures. The typical slide plate is shown in Fig. 16, below.

Figure 16: Slide Plate

When Welding

Place protective covering on PTFE, 25% Glass Filled or Graphite for protection against damage.

Locate the PTFE, 25% Glass Filled on the existing steel surfaces. Use 1/8″ fillet weld. (Weld 1″ and skip 4″). Follow welding sequence as shown in Figure 17 i.e, 1, 2, 3 etc. For welding, use GMAW 0.035 wire or SMAW 3/32″ stick.

If a full weld is desired, use a similar pattern of welding until a full weld is obtained. This method will prevent damage to the PTFE, 25% Glass Filled or Graphite. (A full weld will help prevent seepage of water between the PTFE, 25% Glass Filled or graphite bearing and the support structure.) Avoid overheating, which may destroy the bonding of the PTFE, 25% Glass Filled or graphite to the base plate.

Figure 17: Slide Plate Welding

When In Concrete
Secure the top and bottom elements together with paper adhesive tape. Then attach the bottom element anchor bolts with wire to the form. After the bottom pour is made, repeat on top element. During the first expansive cycle, the tape will break.

Maintenance
Slide plates require no maintenance when utilized as recommended. Backing plates and accessory hardware exposed to certain environments may require protection from corrosion. In this situation, the assembly should be fabricated from corrosion resisting materials such as stainless steel, or protected by suitable coating systems. High-performance prime coatings are provided by the manufacturer when specified or required. Under nominal protected conditions, carbon steel backing plates will require little or no maintenance.

1. Clean pipe to remove scale, paint and other debris with Emery cloth to remove sheen.

2. Use solvent to MEK solvent to remove contamination and ensure that the area is clean and dry.

3. Wipe the inside of the FRP wear pad removing dust and debris

4. Use emery cloth to rough the interior to ensure that there is a good surface for the epoxy to bond.

5. Apply a continuous bead of epoxy adhesive to the inside of the FRP wear pad.

6. Firmly press pad in place rotating pad to spread the Epoxy out.

7. Band FRP pad in place using band straps or ratchet straps.

8. Apply a bead of epoxy around exterior edge of FRP wear pad to ensure a complete seal.

9. Allow 4-6 hours for the Epoxy to harden, and then remove the straps.

Clean the pipe following the pipe cleaning procedure explained in Note #2.
Clean the pipe for the length of the shoe plus 3 inches on either side of where the shoe will be installed. Put the slide plate on the structural support member and center it on the centerline of the pipe.
Remove the slide plate and check the surface of structural support member below for bumps or high points.
Remove any that are found. Replace the slide plate and weld the mounting plate to the structural support member as shown.
Protect PTFE, 25% glass filled, with duct tape or equivalent during welding. Clean the bottom half of the insulation. For Cold Shoes, the polyurethane should be prepared for bonding by sanding it lightly with 60 grit sand paper.

For Cold Shoes apply .042 to .080 inches of wet film thickness of adhesive (Fosters 82-77) to the inside of the insulation, as per manufacturer’s instructions. Slide the assembly under the pipe into position above the slide plate which is mounted on the structural support member (See Note #1 for desired location). Note that field trimming of the calcium silicate may be required for proper fit to the pipe circumference. Lower the pipe onto the bottom half of the saddle. Clean the bottom half of the insulation. For Cold Shoes, the polyurethane should be prepared for bonding by sanding it lightly with 60 grit sand paper. For Cold Shoes apply .042 to .080 inches of wet film thickness of adhesive (Fosters 82-77) to the inside of the insulation, as per manufacturer’s instructions. Slide the assembly under the pipe into position above the slide plate which is mounted on the structural support member (See Note #1 for desired location). Note that field trimming of the calcium silicate may be required for proper fit to the pipe circumference. Lower the pipe onto the bottom half of the saddle.

Align the clamping holes of the top half to the bottom half of the saddle, and press them together. Seal longitudinal joints and the overlapping ends of the jacket with a suitable sealant such as Foster’s Flextra 95-50 or equivalent. Install the clamping bolts, lock washers and nuts. Hand tighten first, check alignment of the saddle and position. When found correct; tighten the nuts applying required torque specified in the drawing.”

 

NOTES:

1. Cold Setting: For axial cold setting, position the support assembly such that after the support has moved, the centerline of the slide plate approximately matches the centerline of the support.
For lateral cold setting, center the support assembly over the slide plate.

2. Pipe Cleaning Procedure: The pipe shall be cleaned prior to the application of the adhesive. Carbon steel pipe should be solvent cleaned and allowed to dry. Stainless steel and high alloy pipes which have been primed shall have the primer roughened with hand tool or power tool, followed by solvent cleaning.
When used in cryogenic applications (below –40ºF), the metal surface must be sand blasted or primed with polyamide epoxy primer.