At times, we have applications where a large control valve is required at high process pressure. This combination requires a pneumatic actuator with substantial area and displacement volume in order to operate the valve. When a positioner is used, the ability to move this valve in a reasonable time becomes a challenge because positioners are not known to have high air flow capacity.
To overcome this, pilot-operated boosters are used in conjunction with valve positioners. Volume boosters have a high CV or air flow capacity that can deliver large amounts of air to move the actuator faster.
Typically, external volume boosters are pneumatically installed in-series between the positioner’s output and actuator’s inlet ports. This adds pneumatic hardware to the entire valve assembly, which increases assembly costs and introduces more chances of an air leak to develop.
The Siemens integral volume booster (IVB) option offers the same type of pneumatic boost that is needed for large control valve applications, but without the additional pneumatic hardware. The IVB is directly connected to the positioner’s output ports, thus eliminating installation costs and the possibility to produce air leaks.