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This week’s feature is on mechanical snubber assemblies custom designed for an oil refinery in California. This project included twenty mechanical snubber assemblies with load ratings from 16,000 lb. to 40,000 lb. and lengths ranging from 65-1/2″ to 103-1/2″. Some of the snubbers were designed to double the standard stroke (up to 12″) by using two MSA-10 sized snubbers back-to-back. All the assemblies were custom designed by adding a carbon steel pipe extension piece. Load tests were performed and the assemblies were shipped in just under four weeks.
Want to learn more about snubbers? Instantly view a recording of a past snubber webinar.
Have you ever wondered which type of snubber to select for your piping system? Should you pick a hydraulic snubber or should you pick a mechanical snubber? Which one is right for your application? This seems to be a common concern for quite a few of our customers, so we have just recently published an article that discusses the pros and cons for both hydraulic and mechanical snubbers. Check out the article, Suitability of Snubbers for Various Applications.
Do you require snubbers for a current or upcoming project? Get pricing today!
A mechanical snubber is a device that permits pipe deflection under normal operating conditions, but when subjected to an impulse load, such as an earthquake, waterhammer, etc., the snubber becomes activated and acts as a rigid restraint to restrict pipe movement as a result of the unwanted impulse loading.
A mechanical snubber uses gears and springs to produce the restraint force when activated.
Mechanical Snubbers
Field testing of snubbers is not recommended. In order to accurately confirm the function of a snubber, a certified test machine must be utilized to accurately simulate impulse loading.
Hydraulic Snubber Being Tested on the STADAS Test Machine
The main criteria to remember when utilizing snubbers is that they are intended to be passive elements during normal operation and will become activated only when that unwanted impulse event is present. When that impulse event dissipates, the snubber will become deactivated and thus produce negligible restraint to pipe deflections under standard operating conditions.
Mechanical Snubber Installed in the Field
Because snubbers are not meant to be active support components, they could be installedat any time during the construction phase. It should also be noted that pipingsnubbers can be retrofit to existing systems at any time.
Close Up View of Hydraulic Snubber Installed in the Field
A pipesnubber is a device that permits pipe deflection under normal operatingconditions, but when subjected to an impulse load, such as an earthquake, waterhammer, etc., the snubber becomes activated and acts as a rigid restraint torestrict pipe movement as a result of the unwanted impulse loading.
Custom Designed Mechanical Snubber Assemblies
A shocksuppressor is another name for a snubber, which is a device that permits pipedeflection under normal operating conditions, but when subjected to an impulseload, such as an earthquake, water hammer, etc., the snubber becomes activatedand acts as a rigid restraint to restrict pipe movement as a result of theunwanted impulse loading.
Mechanical Snubber Assemblies
Sizes of mechanical snubbers for this project range between 18″ and 80″ in the retracted position. The maximum load capacity ranges between 700 and 10,000 lb. Mechanical snubbers function to restrain thermal movement in abnormal circumstances such as earthquakes, hydraulic hammer, and upstream pipe rupture. The snubbers were tested at both high and low rates of loading on a computer controlled hydraulic test machine to ensure quality assurance.
Do you require mechanical snubbers in your piping system? Get pricing today!
Piping Technology & Products, Inc., recently performed its snubber cycle test to prove the durability of a MSA 35 mechanical snubber manufactured for an engineering and construction company at Pine Bluff, Arkansas.
The cyclic test, performed using PT&P’s in-house, horizontal, hydraulic press, is designed to test snubbers at their two modes of operation. At high rates of loading, especially impact, the snubber is expected to provide very high resistance to movement. At low speeds snubbers are to provide very low resistance to movement. Testing a snubber at a low speed displays the normal wear and tear over an extended period of time.
In this case, a cyclic test was performed, in which the MSA 35 Mechanical Snubber with a load rating of 50,000 pounds and design travel of 6 inches was measured at a slow speed response. The low speed force remained at a fairly constant 500 pounds for the 50 hours and 5000 cycles it sustained. This value meets the common criteria that the drag force should be 2% or less than the rated load.
In addition to the snubber cycle drag test, Piping Technology & Products, Inc. has administered other tests such as the burst test for expansion joints. The tests executed by PT&P allow companies to attain the most precise and reliable data available to them. Using this to their advantage, customers will be able to compare data about the recently ordered products, to their individual standards of dependability and durability.
Piping Technology & Products, Inc. and its wholly owned subsidiaries are recognized leaders in manufacturing pipe hangers/pipe supports (variables, constants, cryogenic supports cold shoes, hot shoes, mechanical/hydraulic snubbers, slide bearing plates), expansion joints/compensators (metallic, fabric, rubber, slip-type) and ASME Code Fabrication. PT&P has engineering drawing production stress analysis and full in-house finite element analysis that are used to prove designs. The design software is developed in-house and the calculations contrived are further checked using hand calculations.
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This presentation will cover Pipe Clamps, including Hold-Down Clamps, Riser Clamps, Clevis Hangers, Yoke U-Bolt Clamps, and Structural Supports. Learn how the appropriate type of pipe support is chosen based on the different design conditions. Find out how Finite Element Analysis is used in the design process and view the custom pipe supports designed for extreme applications.
March 30th: Variable Spring Support Design, Size Selection, Installation & Maintenance Webinar 10:00 am OR 2:00 pm
Piping Design and Analysis Influence on Pipe Support Selection and Design
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