Tensioners available for the simultaneous stringing of three conductors (Models YD033A and YD043A)

MR dampers are variable damping-type (semiactive) dampers equipped with built-in electromagnets. They control flow resistance by applying an appropriate magnetic field to MR fluid (*), so that they can deliver the desired damping force.

(*) MR fluid: A fluid composed of oil in which fine magnetic particles are dispersed. This fluid reacts to magnetic fields, the strength of which determines its viscosity.

Structure of MR damper

Overall structure 

• Cylinder-piston structure
• Bypass section equipped with an electromagnet
• Oil tank (accumulator)

Structure of MR damper bypass section

* We can design MR dampers in line with various conditions. For more information, please contact our sales liaison.

TMD dampers reduce vibration by converting the vibration energy of structures into eddy current, which is produced by relative motion between a permanent magnet and a conduction plate, and then dispersed as heat.

Features and structure of TMD dampers

Features

• Directly attachable to structures subject to vibration damping without requiring reaction force receivers.
• The use of non-contact movable parts eliminates the need for maintenance.
• The magnets used remain almost permanently effective.
• They remain effective even against irregular vibrations such as earthquakes.

Structure

* We can design TMD dampers in line with various conditions. For more information, please contact our sales liaison team.

Joint dampers, placed at wooden building joints where pillars and beams meet, adeptly mitigate earthquake damage by flexibly absorbing vibrational energy, reducing building deformation. The main energy absorption occurs in the viscoelastic media, a high polymer material, situated between steel plates, resulting in a simple yet high-tech and effective vibration damping solution.

Features of joint dampers

Types of oil dampers

Our lineup includes standard linear and bilinear type oil dampers, as follows:

Model	Feature	Damper structure	Damping force-speed characteristics
Linear type	An oil damper that is equipped with a sole pressure regulating valve and delivers damping force as represented by the F = CV straight line.
Bilinear type	An oil damper that is equipped with a pressure regulating valve and relief valve and delivers a damping force that increases in proportion to speed until the given speed is reached and at a lower rate after the given speed is exceeded.

— Horizontal type (250 to 2,000 kN)
— Braced type (250 to 2,000 kN)
— Small capacity type (10 to 200 kN)

Force application test

At our previous Tadotsu Engineering Test Center, we performed a force application test on an actual-sized frame, integrating an oil damper as a brace to rigorously assess and confirm the building’s vibration damping capabilities.

* In addition to oil dampers for architectural applications, we develop oil dampers for use with bridges, cranes, and equipment that meet various needs and can design oil dampers to meet various conditions. For more information, please contact our sales liaison team.

Constant Spring Hangers are designed to provide support for piping and equipment in situations where substantial vertical movements are expected. They are utilized when the variability in load, which can be managed by a variable spring hanger, surpasses 25% of the design load. Furthermore, Constant Spring Hangers are selected in instances where load fluctuations exceeding 6% are not allowed, even if the vertical movement is not extensive. STC Constant Spring Hangers feature a mechanism that ensures a consistent support load at any position within the specified travel range.

Standard Model & Type

(1) Suspension Types (Horizontal)

(2) Suspension Types (Vertical)

(3) Floor Mount Types

Applicable Load and Travel Range

The most proper size shall be selected depending on the combination of maximum travel, design load and Model & Type.
For details, please see our Catalog No.2010HNGR or contact our sales or engineering department.

Standard Design Features of STC Constant Spring Hangers are as follows:

1. In order to meet various application requirements, many Model & Type variations are provided :
   • Suspension Model & Type: CSH – A1A, B1, B1A, B2 (Horizontal Spring Type)
   • Suspension Model & Type: CSV – LB1, LB2, HA1 (Vertical Spring Type)
   • Floor Mount Model & Type: CSB – C1, D1 (Vertical Spring Type) , CSH – C1 (Horizontal Spring Type)
2. Coil Spring(s) is(are) pre-compressed and protected by the enclosed spring housing
3. The spring coils are easily visible for inspection through a full length opening on the bottom of the housing.
4. Dry bearings at all rotating points are used to minimize friction forces, and maintain load deviation within ±5% of the design load.
5. Travel Stops for both upper and lower sides are provided in order to prevent full compression and excessive extension of coil spring(s).
6. Each constant spring hanger is equipped with a Turnbuckle for field adjustment of hanger rod length.
7. Load Adjustment of ±10% of the design load can be performed easily on site.
8. Applicable Load Range is from 0.468kN to 320.7kN and travel range is from 50mm to 400mm with 10mm intervals.
   The proper size is selected depending on the combination of maximum travel, design load and Model & Type.
   Special designs for loads and travel beyond the standard size ranges are available upon request.

Standard Types

Type RSA, RSAN and RSAM can adjust the installation length by turning Eye Rod, while type RTS can adjust the installation length by cutting the end of pipe before welding.

Rated Load Range and Applicable Pin-to-Pin Length

Special design for larger load is available upon request.
For details, please contact our sales or engineering department.

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.

Variable Spring Hangers & In cases with highly flexible piping, evaluations are essential to verify that stress fluctuations caused by varying loads remain within the structural limits of the system. Allowable load variability is generally within 25% of the design load as described in MSS-SP-58. Assessments are necessary in situations where piping exhibits significant flexibility to ensure that fluctuations in stress resulting from load variations do not exceed the system’s structural limits.

Standard Model & Type

(1) Suspension Types

(2) Floor Mount Types

Applicable Load and Travel Range

Ranges of Load and Travel vary for each Travel Series (VS1, VS2, VSL2, VS4, VSL4) and Sizes (0~23).
For details, please see our Catalog No.2010 HUGR or contact our sales or engineering department.

Standard Design Features of STC Variable Spring Hangers are as follows:

1. Following types are provided:
   • Suspension Model & Type — Model VSA, Type B and C
   • Floor Mount Model & Type — Model VSB, Type D and F
2. A helical coil spring is pre-compressed and enclosed in the hanger casing to minimize its installation height and time of erection.
3. The spring coils are easily visible for inspection through a full length opening on both sides of the casing.
4. Extra travel is provided for each spring hanger & support at the upper and lower ends of the scale plate to allow for travel beyond the catalog limit.
5. Each suspension type hanger (Type B and C) is equipped with a Turnbuckle for field adjustment of hanger rod length.
6. Type F spring support is supplied with a Load Flange for pipe or pipe shoe mounting.
7. Load-Travel Indicator is integral with Piston Plate.
8. Applicable Load Ranges from 0.059kN to 248.89kN
9. Maximum Travel for each Series
   • VSA 1 — 30mm
   • VSA 2 —– 60mm
   • VSA L2 — 85mm
   • VSA 4 — 120mm
   • VSA L4 — 170mm

The STC Mechanical Snubbers are the result of meticulous engineering, serving a dual-purpose that is both innovative and essential. They excel in their ability to effectively prevent unwanted displacements within piping systems when subjected to the forces of seismic or dynamic events. Simultaneously, they provide the flexibility needed for unimpeded thermal expansion and contraction.

This groundbreaking design represents a seamless fusion of cutting-edge technology. It incorporates a rotary inertia mass, ingeniously engineered to naturally resist sudden movements. Furthermore, it employs a ball screw assembly, renowned for its proficiency in converting linear motion into precise rotary motion.

The importance of this design reaches far beyond its exceptional engineering prowess. Its international recognition and patent protection in diverse nations, such as Japan, the United States, Canada, and the United Kingdom, underline its global significance.

Leveraging a specially developed Japanese grease, STC Mechanical Snubbers have been engineered to operate without the need for maintenance while maintaining an impermeable seal, rendering them exceptionally well-suited for deployment in environments characterized by heightened radiation levels. This exceptional quality sets them apart from Hydraulic Snubbers and underscores their superiority in such challenging conditions.

The design principle of our Mechanical Snubber utilizes an inertia mass which generates a different magnitude of resistance force against the input load in proportion to its acceleration level.
This equation, represented as Mα=F (where M denotes Mass, α signifies acceleration, and F represents the generated force), illustrates a fundamental principle. When subjected to low input acceleration, it leads to the generation of a resistance force at a negligible level, enabling unrestricted movement of piping. Conversely, when exposed to high levels of acceleration, it produces a substantial resistance force, effectively restraining and controlling the vibration of the piping system in its entirety.

Standard Model & Type

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

Applicable Load and Travel Range

For details, please contact our sales or engineering department.

Standard Design Features of STC Mechanical Snubbers are as follows:

1. We provide two assembly options:

• Type A – Standard assembly with extension pipe.
• Type B — Short Type without extension pipe
• 2. We offer different sizes to help you choose the closest rated load that exceeds your design load. The available rated loads are from 1kN to1000kN.
• 3. Standard Stroke of 100mm, 160mm and 250mm are available for each size Snubber up to the rated load 1000kN
• 4.Spherical Bearings with specially designed collars are used at both ends of snubber.