Hydraulic Snubbers (with built-in reservoir)
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 verifications and thorough testing have been conducted to assure the highest reliability of the 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
|Maximum Travel Range
|100, 160 and 250㎜
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:
- Each Symbol of Type denotes the following;
- EA — Standard Type with single piston rod to be assembled with extension pipe for rated load of 3kN～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
- 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.
- Various sizes are provided to allow selection of the proper size having the nearest rated load greater than the design load. The available rated loads are from 3kN to 1000kN.
- Standard Strokes of 100mm, 160mm and 250mm are available for each snubber size up to the rated load of 1000kN.
Longer strokes up to 550mm are also designed and available upon request, if a longer stroke is required.
- Large bore hydraulic snubbers having rated loads up to 5000kN are also designed and available upon request, if larger loads are required.
- By minimizing the number of sealing surfaces, the service life of the snubber unit is extended to twice that of STC’s previous Model SHP.
- Silicon oil is used for all of STC Hydraulic Snubbers for its durability, and specially developed silicon oil having high radiation resistance is used for the snubbers to be located in high radiation areas of nuclear power plants.
- Spherical Bearings with specially designed collars are used at both ends of snubber unit.