The Pipe Support Blog

Constant Hanger Supports for a Power Recovery Plant

Constant support hangers are used to support pipes subjected to vertical movement. The (Fig. PTP 200) constants are designed to support loads from 4,000 lbs to 57,000 lbs. Each weighs approximately 1,500 lbs to 2500 lbs and has a travel of up to 4" with an adjustable travel stop. Their sizes range from 15 to 100.

The advantage of an adjustable travel stop is that the constant is able to "lock in" at any position within the range of travel for a given constant. This alleviates the need for a total "shut down" of the piping system for temporary conditions such as hydrotesting, repair, or replacement.

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Constants for an Oil Refinery in Texas

These constant hanger assemblies are used to support piping systems subjected to vertical movement. They are capable of supporting loads ranging from 3,000 lbs to 63,000 lbs with a travel range of 5". They have dimension between 73" long, 36" tall, and 23" wide to 80" long, 27" tall, and 12 3/4 " wide. Standard testing was performed for quality assurance.

Constants for an Oil Refinery in Texas

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44,000 lb. load Horizontal Upthrust Constant

Piping Technology & Products, Inc. recently fabricated horizontal upthrust constants for loads ranging from 24,000 lb. to 44,000 lb.  These Fig. PTP 200 type U constants are designed for a travel range of 4" to 4 ½". They are fabricated from A36 carbon steel with dimensions ranging from 60"x52" to 80"x52". To meet customer specified installation heights, angles were added to the base of each constant. Load testing was performed to ensure product quality prior to shipping.

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How to Size a Spring Hanger

Piping systems are used to transport gases, liquids and suspended solids between units of a plant. The temperatures of the contents and the pipe when the plant is in operation are often quite different from the ambient temperature of the surroundings. The heat transferred during changes in temperature causes metal pipe to expand and contract. Piping designers must provide for movement due to temperature changes and forces caused by pumps, gravity and other elements of the piping system.Read PT&P's "How to Size a Spring Hanger" Technical Bulletin for more information.

PT&P Specially Designs and Fabricates Constants for a Radiant-Tube Support System
These constants are an essential component of the radiant-tube support system for a reforming furnace. Piping Technology custom designed these units to fit in the limited space available inside the furnace. The bolting patterns for the constants needed to be flexible enough that they could be attached to the supporting structure with any of the support system designs being considered.

Slide Plates: The "Sandwich" Concept
Piping Technology & Products, Inc. uses the "sandwich" concept when applying slide plates to our customers ' systems. Figure 1 shows a "sandwich" composed of two identical slide plates, one on top and another on the bottom. Each slide plate (which is like the bun of the "sandwich") and a low coefficient of friction material which is bonded to the metal backing plate.

Figure 1 (at left)
In a typical application a slide bearing plate is welded to a structural steel member which is strong enough to provide the required support, but whose coefficient of friction is too high.

Figure 2 (at right) shows an application in which a slide bearing plate is welded on top of one steel beam supporting the other beam. When the top beam moves (due to thermal expansion, for example) it slides across the surface of the bearing plate without contacting the supporting another beam. To return to our "sandwich" metaphor, the top half of the "sandwich" is bonded to the sliding beam, and to the bottom half to the supporting beam.

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68" In Height Vertical Upthrust Constants

Piping Technology & Products, Inc. designed and built two, 68" in height 100 U-Type constants for a power plant in Mexico. The vertical upthrust constants were designed to support 48,500 lb. each with a total upward travel of 3". In order to prevent buckling of the constant housing, each constant was designed with five C7 x 14 3/4 lb. channels and a base plate of 26 3/8" x 33 1/4". These unique 100 U-Type upthrust constants were custom designed by PT&P to accommodate limited horizontal space requirement. The constants will be placed opposite to each other on a beam capable of supporting 99,000 lb. load of the pipe, plus the weight of the constants.

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Emergency Field Service Request on Constant

Piping Technology & Products, Inc. and its 24x7 Quick Turn/Emergency Service were put to the test on a Friday evening when they received an emergency call from a company located in Jamaica. The Jamaican company was concerned with existing pipe supports at their location and made a request for a PT&P field services representative to visit and inspect.

An experienced PT&P field services manager arrived at 8:00 p.m. on Saturday to survey and fulfill the request.

The reported problem was a pair of rusted and decayed spring hangers dating back to 1969. After inspection, PT&P’s field services manager concluded that the aged spring hangers could no longer support the piping system due to changes in the design of the system, whereas, failure resulted in additional forces being exerted onto the steam turbine.

Following identification of the measurements, load capabilities, and movements of the spring hangers, it was apparent that the system design did not compensate for the weight of two globe valves that were added to the system at a later date. Thus, PT&P’s field services manager had to take into consideration the weight of these two globe valves when sizing the replacement parts.

PT&P supplied and delivered two Type G variable spring assemblies to Jamaica on the following Monday. Type G assemblies can accommodate unusually heavy loads, and is especially adaptable for avoiding interference in spaces where headroom is limited. In this case, the spring assembly was supporting loads in excess of 2000 lbs. and movement was limited due to its location in the powerhouse.