Model 4000ABP0 pages

A
Model 4000ABP Back Pressure Regulator
Model
4000ABP
Features
•t Control sensitivity of 1/2" water column t
t allows use in precision applications.
Range Screw
•t Large Relief Valve provides high exhaust t
t flows.
Range Spring
•t An Aspirator Tube compensates t t
t upstream pressure build up under flow t
t conditions.
•t A separate Control Chamber isolates the t
t diaphragm from the main flow to eliminate t
t hunting and buzzing.
•t Unit construction lets you service the Model
t 4000ABP without removing it from the line.
Control
Diaphram
Aspirator
Tube
Inlet Port
Relief Valve
Outlet Port
• Canadian Registration Number (CRN)
certification for all territories and provinces.
The Model 4000ABP Pneumatic
Precision Back Pressure Regulator is a
no bleed design regulator that precisely
controls system back pressure.
Operating Principles
The Model 4000ABP Regulator uses the
force balance principle to open the Relief
Valve and vent system pressure when the
set point is exceeded.
Upstream pressure is transmitted through
the Aspirator Tube to the bottom of the
Diaphragm Assembly. When you adjust
the range screw for a specific set point, the
Range Spring compresses and exerts a force
on the top of the Diaphragm Assembly. As
long as the pressure acting on the bottom of
the Diaphragm Assembly t
produces a force less than the spring force
acting on the top of the Diaphragm Assembly,
the Relief Valve remains closed. When system pressure increases, the force on the bottom of the Diaphragm Assembly increases
until it reaches the set point. When system
pressure increases beyond the set point, the
assembly moves upward, lifting the Relief
Valve from its seat and vents the downstream air.
If downstream pressure decreases below the
set point, the assembly moves downward
closing the Relief Valve.
72
800-334-8422
www.fairchildproducts.com