P4500 | Diaphragm Balanced Motor Valve
BelGAS CP
The BelGAS CP P4500 Diaphragm Balanced Motor Valve is a pneumatically operated dump valve designed for low pressure water and oil service where a minimum 10 PSIG pneumatic signal is available. Built around a balanced diaphragm single seat design, the P4500 delivers consistent, pressure-independent valve operation on separators, meters, and water knockouts.
The balanced diaphragm is sized so its effective area equals the opening area of the cage, which cancels out the forces from supply pressure and output pressure acting on the seat. As a result, stem and seat position are controlled entirely by the pneumatic signal rather than by process fluid pressure, allowing the valve to open and close predictably regardless of inlet conditions. A built-in travel indicator provides a visible reference for valve position during operation.
The P4500 is rated to 125 PSIG operating pressure with a 400 PSIG maximum working pressure and a maximum operating temperature of 225°F. The 2″ x 2″ female NPT body accepts a 1/4″ NPTF signal port and delivers a Cv of 23.3 on a 1.50″ trim size, achieving ANSI Class VI shutoff per ANSI/FCI 70-2-013. Elastomer, seat, and cage material options allow the valve to be configured for the specific fluid and pressure conditions of each installation.
Key Features
- Diaphragm balanced single seat design
- Valve position controlled entirely by pneumatic signal, not process fluid pressure
- 10 PSIG minimum pneumatic signal required
- Supply pressure range 10 to 35 PSIG
- Operating pressure 125 PSIG
- Maximum working pressure 400 PSIG
- Maximum operating temperature 225°F (107°C)
- ANSI Class VI shutoff per ANSI/FCI 70-2-2013
- 2″ x 2″ body size with female NPT end connection
- Signal port 1/4″ NPTF
- Cv 23.3 on 2″ line with 1.50″ trim size
- Ductile iron body, bonnet, and housing
- Stainless steel stem and stem guide
- Teflon gaskets standard
- Nitrile diaphragm standard; fluorocarbon optional
- Nitrile o-rings standard; fluorocarbon optional
- Seat options: nitrile, polyurethane, or fluorocarbon
- Cage options: ductile iron or acetal
- Pressure open configuration standard
- Built-in travel indicator for visible valve position reference
- Spring holds seat firmly sealed against cage with no signal applied — fail-closed operation
PERFORMANCE ADVANTAGES
Why the P4500 Performs Where It Counts
Pressure-Independent Valve Control
The balanced diaphragm design equalizes forces from supply and output pressure across the seat, so stem movement is governed solely by the pneumatic signal. This eliminates the influence of fluctuating process pressures on valve position and produces consistent, repeatable dump performance.
Fail-Closed Safety
With no pneumatic signal applied, the internal spring holds the seat firmly sealed against the cage, keeping the valve in the closed position. This fail-closed behavior protects downstream equipment and vessels from uncontrolled discharge in the event of signal loss or supply interruption.
Visual Position Indication
The integrated travel indicator provides an external reference for valve position without requiring additional instrumentation. Operators can confirm open or closed status at a glance during startup, shutdown, or routine field checks.
Configurable Trim for Fluid Compatibility
Seat material options in nitrile, polyurethane, and fluorocarbon, combined with ductile iron or acetal cage choices and matching elastomer selections, allow the P4500 to be specified for a range of produced water and oil service conditions without requiring custom components.