Diaphragm Valves Types and Terms

  • Biotech valves are intended to be used in the biotechnology fields — agriculture, food science, pharmaceuticals and medicine. Biotech valves must be sanitary.
  • Diaphragm diverter valves can be used to divert flow from an inlet to two or more outlets; they can also be used in reverse to feed flow from one line into two or more lines.
  • Diaphragm tank bottom valves are designed for use at the bottom of a tank or vessel, to drain or sample from the tank.
  • Tank bottom valves are designed to eliminate deadlegs or areas where bacteria might become trapped in the valve.
  • Hygienic valves are specially designed to be used in sanitary and aseptic (sterile) applications.
  • Process valves include any type of mechanical device that can stop, start or regulate the flow of liquid, gas, solid material or steam.
  • Weir valves have a raised section, or "weir," on which the diaphragm presses to create a seal.
  • Zero static tee valves have the valve weir (the notch through which material flows) located flush against the interior of the pipe, thus eliminating stagnant areas within the valves.

Actuators - Controls that switch the position of a valve from open or partially open to partially or completely closed. Actuator operation may be manual, pneumatic or hydraulic.

Backpressure - The pressure at the outlet of a relief valve, caused by pressure in the discharge system. Pressures may be constant or variable.

Bellows - A sealing device that prevents leaks between the valve stem and the body of the valve.

Bonnet - A cover fitted over the valve body, which may be removed for valve maintenance.

Cracking Pressure - The pressure at which leaks start to flow through a valve.

EPDM - Ethylene propylene diene monomer. EPDM is a commonly used rubber seal material that is compatible with many chemicals.

Flange - A type of pipe fitting that attaches with nuts and bolts.

Flare - A pipe fitting that uses a socket and a union nut to form a connection. Flares are one of the most crevice-free pipe fittings and may be used for ultrapure processes.

GPM - Gallons per minute. Used to measure flow through a pipe, valve, inlet or outlet.

O-ring - A rubber seal with an "o" shape, used to seal connections between pipes and valves.

Ports - Passages that allow flow into and out of a valve.

Set Pressure - The pressure from an inlet that a valve is adjusted to open, maintain or control under service conditions.

Stem - A rod that spans the inside and outside of a valve, transmitting motion to control the internal disc, which moves to seal or unseal the valve.

U-cup - A seal formed into a u-shaped channel. This type of seal may be used when an O-ring is not desirable.