WBA45 Precision Pneumatic Input Signal Amplifier

Precision Pneumatic Input Signal Amplifier         1/2" & 3/4" – Basic 1/2" Body

Features
• Five signal to output ratios meet most control element requirements.
• Control sensitivity of water column allows use in precision applications.
• Large Supply and Exhaust Valves provide high forward and exhaust flows.
• Soft Supply and Exhaust Valve seats minimize air consumption.
• A balanced Supply Valve minimizes the effect of supply pressure variation.
• An Aspirator Tube compensates downstream pressure droop under flow conditions.
• A separate Control Chamber isolates the diaphragm from the main flow to eliminate hunting and buzzing.
• Optional remote feedback port minimizes pressure drop at final control element under flow conditions.
• The optional adjustable By-pass Valve lets you tune for optimum dynamic response. (1:1 ratio only)
• Unit construction lets you service the WBA45 without removing it from the line.

Operating Principles
When signal pressure on the top of the Signal Diaphragm creates
a downward force on the Diaphragm Assembly, the Supply Valve
opens. Output pressure flows through the Outlet Port and the
Aspirator Tube to the Control Chamber to create an upward force on
the bottom of the Control Diaphragm. When the setpoint is reached,
the force of the signal pressure that acts on the top of the Signal
Diaphragm balances with the force of the output pressure that acts
on the bottom of the Control Diaphragm to close the Supply Valve.
When the output pressure increases above the signal pressure,
the Diaphragm Assembly moves upward to close the Supply Valve
and open the Exhaust Valve. Because the Poppet Valve is closed,
pressure flows down the Connecting Tube to the bottom of the
Motor Diaphragm. This pressure keeps the Supply Valve tightly
closed while in the exhaust mode. The Poppet Valve opens and
excess output pressure exhausts through the vent in the side of the
unit until it reaches the setpoint.