Emerson Process Management’s Fisher VBL booster incorporates a fixed deadband, internal soft seats and an integral bypass restriction.
The VBL’s enhanced performance capability is critical to applications where a valve positioner alone cannot provide the stroking speed required to meet rapidly changing process conditions. It features internal soft seats that yield tight shut-off; reducing unnecessary air consumption and eliminating saturation of positioner relays.
Bypass restriction allows tuning valve response to follow slow signal changes or provide on/off control. This fine-tuning capability does not impact the booster’s deadband.
The VBL booster features an aluminum body with ¼ NPT input and ½ NPT connections. Internal diaphragms, upper and lower valves, and O-rings are of HNBR. Maximum input signal pressure is 10.3 bar (150 psig) with an input to output ratio being fixed at 1:1.