Discover the definitions of terms, components, and standards used in the field of industrial valves, control, and sealing solutions.

(A VAMECA project – continuously updated.)

A

Actuator: A device that mechanically controls the opening or closing of a valve (pneumatic, electric, or hydraulic).

Water Hammer Arrestor: A device that absorbs overpressures in a fluid network.

Flange Anchor – support that prevents mechanical stresses on the piping.

Shaft – rod connecting the actuator to the obturator.

Manual Operation – direct control by lever or handwheel.

ANSI – American National Standards Institute (basis for many pressure classes).

API 607 / 608 – fire test requirements

API 598: American standard defining the leak tests of industrial valves.

ASME B16.34: Pressure valve design standard according to North American standards.

ATEX: European certification for equipment used in explosive atmospheres.

AISI – American Iron and Steel Institute (classification of stainless steel).

• Learn more about the standards in our various articles: Standards & Certifications

Ventilation – air expulsion device in a closed network or controlled air introduction in a circuit.

Compressed Air – fluid used for pneumatic control.

Opening Angle – maneuvering position of a quarter-turn valve.

Abrasive – fluid containing solid particles.

Fluid Acceleration – phenomenon related to sectional reduction.

Upstream / Downstream – respectively denote the inlet and outlet of the flow.

Carbon Steel (CS) – robust material used for steam and hydrocarbon networks.

Stainless Steel (SS / Inox) – corrosion-resistant.

Aluminium – lightweight, used for actuator bodies.

Alloy – combination of metals enhancing mechanical properties.

Anodization – surface treatment enhancing corrosion resistance.

AC/DC – type of electrical power for an actuator.

Actuator Torque – maneuvering torque of an actuator.

Priming – initial loading of a fluid network.

B

Ball or Plug: Rotary component of a ball valve, allowing fluid passage or sealing.

Conical Plug: Variant suitable for viscous or loaded fluids.

Flange: Mechanical part used to assemble two pipes by bolting with a gasket.

By-pass: Diverging line circumventing a valve or equipment.

Position Locking: Function ensuring the valve maintains its position in case of power loss.

Mechanical Stop: Physical limit preventing excessive rotation of the shaft or actuator.

Limit Switch Box: Control accessory indicating the open/closed position of an automated valve.

By-pass: Secondary circuit allowing diversion of fluid for maintenance or balancing.

Position Locking: Device ensuring the valve retains its position in case of energy loss.

Control Loop: System combining sensor, valve, and controller to maintain a process setpoint.

Pressure Balance: Mechanism reducing maneuvering effort on some high-pressure valves.

Bronze: Copper-tin alloy used for its resistance to corrosion and seawater.

Two-Piece / One-Piece: Denotes the structure of a valve body (2 bolted pieces or 1 machined piece).

Brushed (steel): Surface finish typical of high-end stainless steel equipment.

• B16.5 / B16.47 (ASME): Standards defining piping flanges (dimensions, tolerances, pressure classes).

• BSP (British Standard Pipe): Parallel threading standard mainly used in Europe.

• Bar: Unit of pressure measurement (1 bar = 14.5 psi).

• Bore (passage): Internal diameter of the fluid passage (full bore / reduced bore).

• Bleed Valve (purge): Small valve for evacuating trapped air or fluid.

• Test Bench: Machine used for leak and pressure testing (hydrostatic or pneumatic test).

• Bidirectional: Valve ensuring sealing in both flow directions.

• Block and Bleed: Mounting configuration combining a shut-off valve and a bleed valve.

• Line Sweeping: Operation of purging a fluid network before commissioning.

• Local Control Box: Control interface near the valve.

• Packing: Leakage or wear of the sealing around the shaft.

• Thermal Lock: Overpressure caused by expansion of trapped fluid between two closed valves.

C

• Check Valve: Prevents fluid from flowing in reverse.

• Pressure Class (Class): Indicates the maximum allowable pressure according to ANSI standards (Class 150, 300, 600…).

• CRN (Canadian Registration Number): Mandatory registration number for any pressure equipment in Canada.

• Cv / Kv: Flow coefficients representing a valve's capacity to allow fluid passage.

• Valve Body: Main part containing the fluid passage and internal components.

• Condensate: Cooled vapor returning to liquid in a steam network.

D

• DN (Nominal Diameter): Indicates the standard internal diameter of a piping element.

• Double Acting: Operational mode of a pneumatic actuator without a return spring.

• Flowmeter: Instrument for measuring the flow rate of a fluid.

• Shaft Malfunction: Breakage or twisting of a valve control rod.

• Pressure Differential: Pressure difference between the inlet and outlet of a component.

• Gear Reducer: Torque reducer enabling manual maneuvering of a large diameter valve.

E

• Sealing: System's ability to prevent any fluid leakage.

• EPDM / PTFE / Graphite: Materials used for gaskets depending on temperature and fluid chemistry.

• Solenoid Valve: Electrically operated device controlling air or fluid supply.

• Hydraulic Test: Pressure test to verify the mechanical strength of equipment.

• Condensate Evacuation: Process of removing water formed in a steam network.

• Footprint: Space occupied by a valve or a valve/actuator assembly.

F

• Failsafe: Function ensuring the safe position of a valve during a power outage.

• NPT / BSP Threading: Types of threads (American tapered or European parallel).

• Full Bore / Full Passage: Valve whose internal passage matches the pipe diameter.

• Regulation Function: Valve capability to modulate fluid flow.

• Shut-off Function: Valve ensuring complete opening or closing of the passage.

• Corrosive Fluid: Substance attacking chemically incompatible materials.

G

• Globe Valve (Vanne à soupape): Valve designed for fine flow regulation.

• Graphite: Sealing material resistant to high temperature.

• Packing: Element ensuring dynamic sealing around the shaft.

• Guillotine Valve: Sliding blade valve used for loaded fluids.

• Shaft Guide: Part stabilizing the axial movement of a valve shaft.

• Lubrication: Application of lubricant on mechanical components to reduce wear.

H

• High Pressure: Application field beyond 50 bar.

• Hydraulic: Type of actuation using pressurized oil.

• Hot Tap: Connection on an active line without flow interruption.

• Hysteresis: Gap between effective opening and closing positions of a regulated valve.

• Handwheel: Manual maneuvering wheel.

I

• ISO 5211: Standard defining the interface between valve and actuator.

• Position Indicator: Accessory visually indicating valve open state.

• Inox: Steel alloy resistant to corrosion.

• Instrumentation: Set of sensors and measuring devices connected to the valves.

• Isolation: Network section cutting function.

J

• Flat Gasket: Sealing element between two flanges.

• Spiral Wound Gasket: Metallic gasket for high pressures and temperatures.

• Valve Skirt: Lower body part protecting the obturator.

• O-ring: Elastomer ring ensuring dynamic sealing.

K

• Kv: Flow coefficient expressed in m³/h for a 1 bar pressure drop.

• Mounting Kit: Set of parts for fitting an actuator on a valve.

• Maintenance Kit: Set of gaskets and wear parts for maintenance.

L

• Liner: Internal coating ensuring corrosion protection.

• Torque Limiter: Mechanism preventing excessive torque on the actuator.

• Brass: Copper-zinc alloy used for small equipment.

• Linearity: Proportional relationship between valve opening and flow.

M

• Manometer: Instrument measuring fluid pressure.

• Preventive Maintenance: Regular maintenance preventing breakdowns.

• Modulating (Modulation): Progressive regulation function of a valve.

• Wafer / Lug Mounting: Types of butterfly valve connections.

• Diaphragm: Flexible element separating two pressure zones.

N

• NPS (Nominal Pipe Size): Standardized diameter in inches according to North American standards.

• CSA Standard: Canadian certification for safety and compliance.

• Leakage Class: Sealing classification according to ISO 5208 / API 598.

• Neutralization: Acid fluid treatment process before discharge.

O

• Orifice: Internal passage through which fluid flows.

• Open/Close Time: Time required to open or close the valve.

• Overtorque: Torque applied exceeding design tolerance.

• Orientation: Installation position affecting performance (horizontal/vertical).

P

• PN (Pressure Rating): Indicates maximum pressure in bar.

• Service Pressure: Maximum continuous use pressure.

• PS Automation: German manufacturer of electric actuators distributed by VAMECA.

• Drain Valve: Evacuates condensates or air bubbles from a network.

• Reduced Bore: Internal section smaller than the nominal diameter.

Q

• Quick Exhaust Valve: Rapid discharge valve in a pneumatic circuit.

• Surface Finish Quality: Level of finishing influencing sealing.

• Quadrant: Standard rotation angle of a quarter-turn valve (90°).

R

• Regulation: Continuous flow adjustment to maintain a setpoint.

• Pressure Reducer: Device stabilizing downstream pressure.

• Position Feedback: Signal indicating open/close state of an automated valve.

• Shaft Breakage: Mechanical failure due to excessive torque.

S

• Valve: Safety component releasing overpressure.

• Seat: Sealing surface between the obturator and the body.

• Smart Positioner: Intelligent positioner with digital communication.

• SIL (Safety Integrity Level): Certified functional safety level.

• Isolation: Complete fluid shut-off function.

T

• Torque: Force needed to maneuver a valve.

• Thermal: Relating to the fluid's operating temperature.

• Visual Indicator: State indicator on a motorized valve.

• Tapping: Machining of an internal thread for connection.

U

• UL / FM: North American safety and fire certifications.

• Unidirectional: Valve ensuring sealing in one direction only.

• Industrial Utilities: Set of an auxiliary plant's fluids (water, air, steam).

V

• VAMECA: Canadian distributor of industrial valves and sealing solutions.

• Valve: Device for shutting off, regulating, or safeguarding a fluid circuit.

• Three-Way Valve: Allows mixing or distributing a fluid between two circuits.

• Vexve: Finnish manufacturer of district heating valves.

W

• Wafer: Compact mounting type between two flanges.

• WCB: Material designation (cast steel ASTM A216).

• Water Hammer: Pressure wave caused by sudden valve closure.

X

• Xylan®: Fluoropolymer coating (often blue) applied on bolts, flanges, and valve parts to enhance corrosion resistance and reduce tightening torque.

• X-type Strainer (X Filter): Inclined basket filter providing efficient filtration in a compact space, often used in steam or liquid processes.

• X-block Manifold: Cross valve block used for instrumentation to centralize several functions (isolation, purge, testing).

• X-flow: Term used to designate cross-flow configurations in multi-way valve systems or leakage test circuits.

Y

• Y-Strainer (Y Filter): Mechanical filter retaining solid particles in a fluid.

• Yoke: Support connecting the actuator to the valve body.

Z

• ATEX Zone: Environment classified as explosive risk.

• Zinc-nickel: Corrosion-resistant coating for mechanical parts.

• Zero Leakage: Absolute sealing level (Class A).