The C700SW diffuser is the
Butt-weld version of CU Services LLC's family of
high-pressure-drop diffusers. It can be used
individually or as a multi-stage orifice plate system of two
or more units placed in series to eliminate the damage
that is caused by control valve cavitation.
For example, two of the most difficult flow control
problems in a power plant are the control of the Boiler
Feed Pump recirculation and boiler feed pump warm-up
systems. Another example is the boiler blowdown system.
These diffusers can be used for any flow-restriction
Because of the high-pressure drops involved with
these high temperature liquid streams, the fluid flashes
and/or cavitates at the exit of the control valve.
This erodes both the control valve and the downstream
piping. In addition the resulting pounding as the fluid
implodes causes unacceptable noise and vibration of the
piping. In some cases, the control valve, the downstream
piping and the hangers must be replaced in a matter of
One of the most respected hydraulic laboratories in the country has validated the performance for our multistage diffuser design for the pump recirculation system for a nuclear power plant.
The Control Valve should be located upstream of the diffusers. For on/off control situations, the control valve should take approximately 20-30% of the pressure drop and the diffusers take the rest of the drop. For modulating control situations, the control valve should take 60-70% of the pressure drop and the diffusers take the rest of the drop. This will greatly reduce the initial cost and the maintenance cost of the control valve.
Another important benefit of a multi-hole diffuser is that the energy of the discharge jets is dissipated in a much shorter distance than the jet from a single orifice. This would prevent damage to nearby elbows, etc.
The Nuclear Regulatory Commission notice 98-45 has warned of flow induced vibration damage that can be caused by condensate flow in single-hole, single orifice let-down systems. View this report on the www.nrc.gov web site.
The NRC has also cautioned against using torturous path valves or devices because of a plugging potential view the Nuclear Regulatory Commission Report. Our diffusers are not torturous path devices. We design them to minimize the potential of plugging.
The C700BW body is fabricated from the highest quality of forged bar stock ASME-SA479-316SS. Pressure rating is the same as Sch 160 316 SS pipe.