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Pipework Damper (PD)

 

Dynamic vibrations during pipe system operation are caused by internal and external vibration sources as shown below.

These pipe vibrations increase the stresses in pipe section and cause damage in weak parts such as welds and joints.

 

External vibration source

- Vibration of fixed frequency, caused by rotating and reciprocating motion of machine
- Earthquake or dynamic vibration 

 

Internal vibration source

- Internal vibration caused by unsteady turbulence of internal fluid
- Impact load acting on elbow, etc.  

 

• The dynamic vibration excited by internal and external vibration sources of pipe system has wide-ranging frequencies. Pipe systems are sensitive to vibration due to their flexibility and low damping characteristics.

• Even under normal operating conditions, it is tuned to the natural frequency of pipe system to cause amplification vibration while the low damping characteristics of pipe system exacerbate the situation.

 

The plant pipe system allows thermal deformation, but requires the devices that reduces the stress caused by vibration and protects the piping system in case of excessive vibration.

Various devices are used to prevent damage to the pipe system. The requirements for such devices are presented below.

 

• High damping performance (dynamic vibration, earthquake, shock, etc.)
• High durability without need for maintenance
• Resistance to radiation, temperature, etc.
• Low reactionary force loading on structure in case of temperature-induced expansion
• Immediate response to vibration
• Assurance of stability in case of abrupt external force such earthquake and shock load on piping system
• Low maintenance cost

 

Our company’s Pipework Damper, which shows speed-dependent behavior, and Pipework Restrainer which cushion shocks and limit displacement, are mounted in the pipe system to add rigidity and damping characteristics of the whole system, enabling optimal design for control of pipe vibrations with wide-ranging frequency properties.

 

Our company’s pipework damper undergoes vertical and horizontal test as shown in the Figure below, and the load-displacement curves of the VPD-50 by frequency are presented below.

 

1. Test scene

    
                                 Horizontal test                                                                              Vertical test
 

 

2. Load-displacement curve of pipework damper by frequency(horizontal, VPD-50)

 

Our Pipework Damper conforms to requirements above and has the main advantages as below.- Optimization of stiffness and damping characteristics of entire pipe system based on speed-dependent behavior

• The use of speed-dependent viscous fluid causes low load at low speed such as temperature expansion
• There is no wear-resistant part inside structure, making the maintenance unnecessary.
• Suitable for pipe systems with three-dimensional behavior through behavior
• Silicone fluids used as viscous fluids are non-toxic, non-flammable and little temperature-dependent
• Immediate response to dynamic vibration due to absence of cap, valve, external fluid reservoir, etc.

 

3. Installation example

 

 

      

 

4. Installation site photo