Fronek Anchor/Darling Enterprises, a division of PT&P designed and fabricated hydraulic snubbers for a geothermal facility in California. The Fig. 510 AD snubbers ranged in size from 34-3/4″ to 37-5/8″ piston-to-piston and were designed for a 50,000 lb. maximum load, 5″ cylinder size and a 6″ stroke. The Fig. 511 AD snubbers ranged in size from 56-15/16″ to 59-5/16″ P-P and were designed for a 20,000 lb. maximum load, 2-1/2″ cylinder size and a 6″ stroke. Hydraulic snubbers are designed to protect the piping system when a sudden, heavy load is applied (such as an earthquake of high intensity), which can cause serious vibrations leading to complete destruction. A custom three-bolt pipe clamp fabricated from carbon steel was designed to fit in a limited space. A cycle test throughout the full stroke from zero to fully extended was performed prior to shipment.

Follow these 7 steps below to maintain and extend the life span of your hydraulic snubber.

Hydraulic Snubber Assembly

1. Observe the fluid level to make sure there is sufficient fluid for the snubber to operate
2. Check for leaks – If the fluid level is decreasing, determine the cause and effect remedial action.
3. Check the condition of the load pins and spherical ball bushings. Apply a high pressure grease for long-term benefits.
4. Check the condition of the exposed portion of the piston rod. Check for scoring, paint or other physical damage.
5. Check the condition of the piston rod wiper. Verify that it’s in position and working effectively.
6. Check for evidence of abuse like welding arc strikes, bent or dented parts, scratched paint, etc.
7. Finally, check the overall physical appearance. This encompasses all of the above.

A total of eight big ton spring supports, “mega tons” were designed and manufactured to support two reactors in a power plant weighing approximately three million pounds each. The mega ton pictured incorporated eighteen individual spring coils to produce a load capacity of approximately 602,000 lb. and a spring rate of 112,500 lb./in. It was designed with eight Bronzphite® slide plates that measured 12″ x 12″. The 12″ x 12″ slide plate selection was based upon the ability to position individual squares across the load flange surface while simultaneously providing the total slide plate surface area required to support the operating loads.

By using individual slide plate squares, the fabrication and assembly time was reduced because a standardized mounting procedure could be incorporated and repeated as necessary for each big-ton load flange subassembly. Overall, the slide plates were incorporated into the design to reduce the horizontal forces which would be imparted onto the big-ton spring’s load flange during lateral deflection (movement) of the reactor.

Bronzphite® slide plates, in particular, were selected because these big-tons will be used in a location which will see continuous “cold-to-hot” operating cycles and as a result, the robust nature of Bronzphite® proved more advantageous than other types of slide plates. The other two designs used nine slide plates, one with fifteen individual coils to produce a operating load of 594,000 lb. and a spring rate of 250,050 lb./in. The other design had an operating load of 300,000 lb. and a spring rate of 106,000 lb./in.

These F-type variable spring supports are fabricated from carbon steel with a hot dipped galvanized finish and designed with guided load columns to provide stability for minimum lateral movement. The fig. 46 pipe saddles are also fabricated from carbon steel with a HDG finish and lined with PTFE, 25% glass filled material. The pipe saddles are designed for 8″ to 36″ diameter pipe sizes, and the entire assembly is 50″ in height. These variable-saddle support assemblies are capable of supporting up to 22,300 lb. and 1″ vertical movements. We performed standard spring loading tests and a Q.C. inspection prior to shipping to an offshore oil and gas platform near Malaysia.

Slide plates are easy to maintain if you follow these certain steps when inspecting them. Visit our visual media section to learn what four steps to take for Slide Plate Inspection and Maintenance.

Our field service manager, David Baker, will show you what to look for when inspecting your PTFE slide plates. If you have any questions, feel free to call David Baker at 713-992-7048 or email us at info@pipingtech.com.

B31.1 Operations and Maintenance

According to ASME B31.1 Chapter VII Par. 140 a program shall be established for the assessment and documentation of the condition of all CPS (Covered Piping Systems) in power plants.

CPS Systems are defined in Chapter 1 Par 100.2, as systems on which condition assessments are to be conducted. This includes the following systems as a minimum.

NPS 4 and larger main steam, hot reheat steam, cold reheat steam, and boiler feedwater piping.

NPS 4 and larger systems that operate above 750°E (400°C or above 1,025 psi (7,100 kPa)

Other systems may be included as CPS by an Operating Company, based on their judgment. Appendix V of the code is titled ‘Recommended Practice for Operation, Maintenance, and Modification of Power Piping Systems’. This addendum is non-mandatory; however many  Power Industry operating companies’ insurance carriers are now invoking Appendix V with increasing frequency, and this is affecting conditions of their agreements with the operating companies.

Piping Technology and Products Inc. (PT&P) has for some time been performing surveys and assessments in accordance with part H of Par. 140, that requires hot and cold walk-down readings and assessment of pipe supports, operated within the creep regime of the pipe.    These assessments are helpful in identifying, sagging lines, deformation of supports, and damage caused by upset conditions, and/or incidents, attributable to operational malfunctions, dynamic/thermal or hydraulic events.

PT&P has been performing this service for many power generation companies. Preparation of documentation, retrieval and compilation of files for a CPS assessment, has just been completed for a major U.S power generation company. Ten large power plants were involved, and the original predominantly high-energy pipe support drawings, all engineered and designed by PT&P, were retrieved from PT&P archives dating back ten years.

Please feel free to contact us at david.baker@pipingtech.com and we will be happy to answer any of your technical questions about our survey capabilities, as well as any other engineering or field services that your organization may need.

These high temperature pipe supports have a 25″ outside diameter, and were custom designed for a granular activated carbon manufacturing plant in Hawaii. They are fabricated from A-36 carbon steel with 10″ thick high density calcium silicate insulation. The hot shoes were designed for a 4″ diameter pipe-line, temperatures up to 1,800°F and an operating load of 1,000 lb. Standard Q.C. and dimensional tests were performed prior to an expedited shipment.

Do you require hot shoes on an upcoming project? Get pricing today!