Piping Technology and Products Logo

Piping Technology & Products

Loading
 
  Experienced Manufacturer of Pipe Supports since 1978
Call Us: (713) 731-0030 Toll-Free: (800) 787-5914   Se habla español
 

 
Snubbers Homepage > Technical Articles > Suitability of Snubbers for Various Applications

 

request-a-quote

Suitability of Snubbers for Various Applications
By Dr. Hyder Husain Ph.D.
March 9, 2011

Snubbers are used as restraining devices to control abnormal movement of pipes and equipment due to dynamic events such as earthquakes, turbine trips, safety/relief valve discharge, rapid valve closure, or rupture of pipes. The design of a snubber allows free thermal movement of a component during normal operating conditions, but restrains the component in abnormal conditions.

The snubber restraint forces, as described above, can be generated using either mechanical or hydraulic methods.

Hydraulic Snubbers
Hydraulic snubbers have a piston which is relatively unconstrained during relatively low velocities as would be seen in normal thermal expansion/contraction cycles or slow oscillation of pipes. At high displacement rates, the piston "locks up" and the snubber acts as a rigid restraint.

Hydraulic Snubber
Hydraulic Snubber with an Overall Stroke of 6"

Currently available hydraulic snubbers use a high viscosity (~ 1000 cStokes) fluid. Typically, the motion of the snubber-fluid shuts off the valve when the piston velocity reaches 8”/min or more. As a result the snubber acts as a rigid component and transfers the shock load to the rigid foundation, saving the upstream components.

Mechanical Snubbers
Mechanical SnubberSimilarly to hydraulic snubbers, mechanical snubbers use a telescoping cylinder to permit free movement of the pipe under normal operating conditions. When the threshold acceleration of 0.2 g’s is exceeded, a internal mechanism of the snubber activates, thereby locking the telescoping cylinder and subsequently producing our restraint force.

Hydraulic vs. Mechanical Snubbers
Because hydraulic snubbers have fewer internal components, they are preferred in outdoor applications or where a corrosive environment is present. Additionally, hydraulic snubbers can be easily designed to accommodate a wide range of pipe displacement.

Mechanical snubbers are optimum solutions for piping used in high radiation areas such as those seen in nuclear power plants because they do not utilize hydraulic fluid that may become degraded in radioactive environments.

Furthermore, mechanical snubbers require less maintenance overall and are considered “solid state” support components in the piping system. Hydraulic snubbers conversely require routine inspection to detect leaking seals or loss of hydraulic fluid.

Dynamic Response
In regards to dynamic response, mechanical snubbers react consistently regardless of their Hydraulic Snubber and Mechanical Snubberposition during either compression or extension modes. However, hydraulic snubbers may show some variation in their dynamic response depending upon the piston location.  Therefore, when choosing a hydraulic snubber for a piping system, one must carefully determine the amount of stroke needed to adequately position the snubber piston orientation for optimum functionality.

Mailing: P.O. Box 34506, Houston, TX 77234-4506 Location: 3701 Holmes Road, Houston, TX 77051
Our Subsidiaries: U.S. Bellows: Metallic & Fabric Expansion Joints, Bellows
Sweco Fab: ASME Vessels, Pig Launchers, Spectacle Blinds
 Pipe Shields: Pre-Insulated Pipe Supports, Slides, Guides & Anchors

Fronek Anchor/Darling
: Snubbers, Sway Struts & Sway Braces
Phone: (713) 731-0030 Toll-Free: (800) 787-5914 FAX: (713) 731-8640 info@pipingtech.com

©2017 Piping Technology and Products, Inc. All Rights Reserved. Contact Us | Privacy Policy