Made in: Japan
Manufacturer: SANWA TEKKI
Model : Hydraulic Snubbers

Hydraulic Snubbers protect piping systems and components by restraining undesirable displacement due to seismic or other types of dynamic loading, while, allowing free movement during the thermal displacement mode.
The STC Hydraulic Snubber design provides this essential dual function using a sophisticated valve mechanism. The design also includes an internal, flexible reservoir in place of the more conventional oil reservoir mounted outside of the snubber body. Comprehensive design verification and meticulous testing have been conducted to ensure the highest level of reliability for STC hydraulic snubbers.Since STC snubbers have been in service for decades, they have demonstrated trouble-free performance and are easy to maintain; thus assuring maximum protection for piping systems subjected to occasional dynamic events.

The design principle of the STC Hydraulic Snubber includes a hydraulic system controlled by a valve mechanism. The magnitude of the resulting resistance force is a function of input velocity. Namely, CVn=F (C=Constant, V=Piston Velocity, n=Valve Property, F=Force generated)

Standard Model & Type

Please see 1 of Standard Design Feature for classification of each Type.

Applicable Load and Travel Range

Larger load up to 5000kN and longer stroke up to 550㎜ can be designed and available upon request.
For details, please contact our sales or engineering department.

Standard Design Features of STC Hydraulic Snubbers are as follows:

1. Each Symbol of Type denotes the following;
   • EA is the standard type featuring a single piston rod, designed for assembly with an extension pipe, suitable for rated loads ranging from 3kN to 250kN.
   • FA — Short Type with single piston rod without extension pipe for rated load of 3kN～250kN
   • EB — Standard Type with double piston rod to be assembled with extension pipe for rated load of 400kN～1000kN
   • FB — Short Type with double piston rod without extension pipe for rated load of 400kN～1000kN
   • G — Previous Type with single piston rod and extension pipe for rated load of 400kN～1000kN
2. STC Model SN Hydraulic Snubber provides two valve options:
   • Model SN : Poppet Valve option; used to restrain in both directions tension and compression.
   • Model SNS : Check Valve option; used to restrain only in the tension direction. (Model SNS is used to restrain undesirable displacement and dynamic loading of large valves, such as Main Steam Stop Valves).
   • Note : Orifice valve option; effective to reduce the vibration velocity, is also available for conventional Model SHR.
3. We offer a range of sizes to allow for precise selection, ensuring the nearest rated load exceeds the design load. Rated loads are available from 3kN to 1000kN.
4. Each snubber size, up to a rated load of 1000kN, comes with standard strokes of 100mm, 160mm, and 250mm.
5. Upon request, longer strokes up to 550mm can be provided if a greater stroke length is needed.
6. For applications requiring larger loads, we offer large bore hydraulic snubbers with rated loads up to 5000kN upon request.
7. Our design minimizes the number of sealing surfaces, resulting in a service life that is twice that of STC’s previous Model SHP.
8. All STC Hydraulic Snubbers utilize durable silicon oil. Specifically, in high-radiation environments within nuclear power plants, we use specially formulated silicon oil with high radiation resistance.
9. Spherical bearings with custom-designed collars are incorporated at both ends of the snubber unit for optimal performance.