Valve Terminology

What Is Pressure Drop Across a Valve? Direct Answer Pressure drop across a valve is the difference in fluid pressure measured between the upstream and downstream sides of the valve during flow. It results from flow restriction, turbulence, and energy losses within the valve body and is typically expressed in psi, bar, or kPa. Key […]

What Is Valve Torque? Direct Answer Valve torque is the rotational force required to open, close, or modulate a valve under specified operating conditions. It is typically expressed in Newton-meters (Nm) or pound-feet (lb·ft) and depends on valve design, seat load, packing friction, differential pressure, and fluid characteristics. Key Takeaways Valve torque is the rotational

What Is a Valve Actuator? Direct Answer A valve actuator is a mechanical device that converts energy — such as pneumatic, electric, or hydraulic power — into motion to open, close, or modulate a valve. It provides the required torque or thrust to operate the valve automatically or remotely under defined control and pressure conditions.

What Is Control Valve Rangeability? Direct Answer Control valve rangeability is the ratio between the maximum controllable flow and the minimum controllable flow a valve can regulate while maintaining specified performance accuracy. It indicates the valve’s effective control span under defined operating conditions and is typically expressed as a numerical ratio such as 50:1 or

What Is Flow Coefficient in Valve Engineering? Direct Answer Flow coefficient is a quantitative parameter that expresses the flow capacity of a valve or flow-restricting device under specified conditions. It relates flow rate to pressure drop and fluid properties, allowing engineers to size and compare valves. In U.S. practice it is expressed as Cv; in

What Is Cv Value in Valve Engineering? Direct Answer Cv value (flow coefficient) is a numerical parameter that quantifies a valve’s flow capacity. It is defined as the number of U.S. gallons of water at 60°F that flow through a fully open valve per minute with a 1 psi pressure drop across it. Key Takeaways

What Is Double Block and Bleed (DBB) in Valve Systems? Direct Answer Double block and bleed (DBB) is a valve arrangement or valve design that provides two independent sealing surfaces (blocks) in series with a means of venting or draining the cavity between them (bleed). It enables positive isolation and verification of seal integrity under

What Is a Trunnion Mounted Ball Valve? Direct Answer A trunnion mounted ball valve is a quarter-turn valve in which the ball is mechanically anchored by upper and lower trunnions, allowing it to rotate while being supported on fixed bearings. This design reduces operating torque and enables reliable sealing under high-pressure and large-diameter service conditions.

What Is the Difference Between Full Port and Reduced Port Valves? Direct Answer Full port valves have an internal bore diameter equal to the nominal pipe size, allowing unrestricted flow through the valve. Reduced port valves have a smaller internal bore than the pipe, creating a flow restriction. The difference affects pressure drop, flow capacity

What Is the Difference Between NPT and BSP Threads? Direct Answer NPT (National Pipe Taper) and BSP (British Standard Pipe) are two distinct pipe thread standards used for threaded pipe and valve connections. They differ in thread angle, pitch, sealing method, and dimensional standards. NPT uses a 60° thread angle with tapered sealing, while BSP