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Ventilordlista Engelska

Valve Terminology

A.
ANGLE VALVE:
A variant of the globe valve design, having pipe openings at right angles to
each other, usually with one opening in the horizontal plane and one in the
vertical plane.
ANTI VACUUM VALVE:
An automatic type of air valve preventing the formation of vacuum in tanks or
pipelines.
AUTOMATIC PROCESS CONTROL VALVE:
For controlling rate of flow relative to value.
AUTOMATIC STOP CHECK VALVE:
A combination check and shut off valve designed primarily for use on multiple
boiler installations.

B.
BALL CHECK VALVE:
A valve used to stop the flow of media in one direction, but to allow
unrestricted flow in the opposite direction.
The closure member used is spherical or ball shaped.
BALL VALVE:
A quick opening block valve, usually soft sealed to provide very tight shut-off.
The name is derived from its spherically shaped closure component.
BELLOWS SEAL VALVE:
A valve which utilizes a bellows in the body neck for primary sealing against
external leakage; usually includes a stem packing for secondary sealing.
BLOW-OFF VALVE:
A valve designed specially for blow-off service and used in blow-off lines.
Also, called "blow-down valve." Cleaning sludge from a boiler.
BONNET ASSEMBLY:
Consists of bonnet and valve actuator.
BONNETLESS:
Term frequently used for a pressure seal bonnet.
BOTTOM FLANGE:
A plate covering an opening in the bottom of the valve body.
BRONZE TRIM OR BRONZE MOUNTED:
An indication that certain internal parts of the valves known as trim materials
(stem, disc, seat rings, etc.) are made of brass or bronze.
BUBBLE TIGHT:
The description of a valve seat that, when closed, prevents the
leakage of visible bubbles due to differential pressure across the seats.
BULK HEAD VALVE:
A gate valve.
BUTTERFLY VALVE:
A valve deriving its name from the winglike action of the disc, which operates
at right angles to the flow.
BY-PASS VALVE:
A valve used to divert flow around or past the part of the system through
which the flow normally passes.
BELLOWS SEAL:
A method of sealing the valve stem in which opposite ends of the sealing
component are fastened to the bonnet and stem respectively, expanding
and contracting with the stem travel (see "Bellows Seal Valve" on previous page).
BRASS TO IRON:
The designation for a brass disc and an iron seat, or vice versa, in a valve.

C.
CLAMP GATE VALVE:
A gate valve whose body and bonnet are held together by a "U" bolt clamp.
COCK:
A simple form of block valve having a hole in a tapered plug which is rotated
to provide a passageway for fluid.

D.
DIAPHRAGM:
A flexible disc used to separate the control medium from the controlled
medium and which actuates the valve stem.
DIAPHRAGM CONTROL VALVE:
A control valve that is actuated by diaphragm, or one having a
Spring-Diaphragm actuator.
DIAPHRAGM OPERATED VALVE:
Any valve which is operated by a diaphragm, but usually refers to a
diaphragm control valve.
DOUBLE BLOCK AND BLEED:
A double valves with a bleed valve 1 cated
between them, for the most critical block valve applications.
An open bleed valve with no flow is the most positive means available for
proving that there is no-leakage through a closed double valve assembly.
DOUBLE BLOCK AND BLEED VALVE:
A single valve, of a type that affords simultaneous upstream and downstream
sealing, equipped with a bleed valve on the body between the upstream and
downstream seats. An open bleeder with no flow gives positive assurance
that there is no leakage through the closed valve.
(A single properly designed double-seated block valve has a sealing
capability equivalent to that of double block valves; the second valve is
included for the most critical applications as insurance against mechanical
failure or seat fouling of a single valve.)
DROP TIGHT:
A term signifying that a valve shall not pass water or air droplets when it is
closed and pressured.

E.
ECCENTRIC BALL VALVE:
Essentially the same as a ball valve except that the offset of the ball and stem
axis with respect to the body seat rings imparts a wedging action during valve
closure which affords relatively tight shutoff even with metal to metal seating.
END CONNECTION:
A reference to the method of connecting the parts of a piping system, e.g.,
threaded, flanged, butt weld, socket weld.

F.
FACE-TO-FACE DIMENSIONS:
The dimensions from the face of the inlet port to the face of the outlet port
of a valve or fitting.
FACING:
The finish of the contact surface of flanged end piping materials.
FLAP VALVE:
A non-return valve in the form of a hinged disc or flap, sometimes having
leather or rubber faces; used for low pressure.
FLASH POINT:
The temperature at which a fluid first gives off sufficient
flammable vapor to ignite when approached with a small flame or spark.
FLAT FACED BONNET JOINT:
The point of connection between a valve body and bonnet when the bonnet
is not recessed into the body but is seated on a flat surface.
FLAT FULL FACE GASKET:
A flat gasket covering the entire surface of the parts being joined.
FLEXIBLE WEDGE DISC:
A valve disc which has a solid center but which is made flexible at the outer
periphery, usually by a saw-cut in the plane of the disc which leaves two thin
metal lips for better conformability with the body seat rings.
FLOW REGULATING VALVE:
For controlling rate of flow.
FREE BALL VALVE:
A valve in which a ball is free to rotate in any direction.
FUSIBLE LINK OR FIRE VALVE:
A fire preventiuon valve which has a weighted lever hold open by a wire ans
fusible link which melts at an increase of room temperature.

H.
HAMMER BLOW HANDWHEEL:
Provides additional operating torque to facilitate operation of valves in services
where the plain handwheel may be insufficient yet where gearing is not
necessary.
HAMMER BLIND VALVE:
A valve used in applications where no line movement is possible and where
spillage is unacceptable.
HOSE END VALVES:
Valves for utility services which have fittings for con-nection to a hose.
HYDRAULIC VALVE:
A control valve for water, oil or hydraulic systems.

I.
INNER VALVE SEAT:
Another term for VALVE SEAT RING.
INSIDE SCREW, NON-RISING STEM:
A type of stem found in gate valves. The disc rises on the threaded part of
the stem inside of the stem rising through a threaded portion of the bonnet.
INSIDE SCREW, RISING STEM:
A stem found on gate and globe valves.
The stem rises as the handwheel is turned.
The term inside screw means that the threads are inside of the bonnet.
INLET PORT:
The port which is connected directly to the upstream side of a fluid system.

J.
JET DISPERSAL VALVE:
A valve incorporating an element by virtue of which the energy within the
emitting jet is dissipated.

L.
LANTERN RING TYPE GLAND:
A chamber with lantern spacer and rings of packing
below to wipe stem clean before it passes into the sealing rings above.
LAPPING-IN:
Rubbing and polishing a surface such as a disc face to obtain a smooth
bearing surface contact with the body seat rings.
LIFT CHECK VALVE:
A form of check valve in which vertically rising flow opens
the sealing disc or piston, and reverse pressure causes the disc to drop back into its seated position to prevent reverse flow.
LUBRICATED PLUG VALVE:
A valve designed with a groove which permits a lubricant to seal and lubricate
the valve, and to serve as a hydraulic jacking force to lift the plug within the body.

M.
MAIN BODY ASSEMBLY:
Another term for VALVE BODY ASSEMBLY.
MULTI-PORT PLUG VALVE:
A plug valve that has more than two port openings.

N.
NEEDLE POINT VALVE:
A type of globe valve having a needle point plug and a small seat orifice for low flow metering.
NON-RISING STEM:
A type of valve stem which turns but does not rise when the valve is operated.

0.
OS & Y:
A type of valve stem screw, specifically "outside screw and yoke."
The packing is between the stem screw and the valve body, isolating the
fluid from the stem threads.
Useful for abrasive and corrosive applications, and for most refinery applications.
OUTSIDE SCREW, RISING STEM:
See "OS & Y" and "Rising Stem" definitions.

P.
PACKING:
A sealing device consisting of deformable material or one or more mating
deformable elements.
Reshaped by manually adjustable compression to obtain or maintain
effectiveness as a seal against external leakage.
PACKING ASSEMBLY:
That part of a valve which contains the packing gland, the packing nut, etc.
PACKING BOX ASSEMBLY:
The part of the bonnet assembly used to seal against leakage around
the valve stem.
PACKING NUT WITHOUT GLAND:
A packing nut to compress the packing in the stuffing box of a valve.
PENSTOCK:
A single faced type of valve consisting of an open frame and a door and used
in terminal positions only.
Normal located in tanks or channels for controlling flow in to a pipe.
PINCH VALVE:
Has a flexible hose extending completely through the valve bore, and is
handwheel or cylinder operated. The hose is "pinched" to effect closure.
PISTON CHECK VALVE:
See LIFT CHECK VALVE.
PLATE VALVE:
A gate valve incorporating a sluicing effect.
PLUG TYPE DISC:
A type of disc used in valves; tapered plug disc and cone shaped seat having
wide bearing seating surface.
PORT:
An internal-external terminus of a pasage in a component.
The inlet or outlet of a valve. Sometimes used to refer to the valve seat opening.
PRESSURE SEALED BONNET:
A valve bonnet which does not depend upon bolting and gaskets for a
tight seal.
As the line pressure increases, the self-energizing seal becomes tighter.
PRESSURE DIFFERENTIAL:
The difference in pressure between any two points of a system or a component.
Also known as pressure drop or AP.

R.
RADIATOR VALVE:
A valve controlling the flow of water through a radiator.
RING, WIPER:
A ring which removes material by a wiping action.
RISING STEM:
A type of valve stem which rises when the valve is opened.
NON-RISING STEM:
A type of valve stem which turns but does not rise when the valve is operated.
RING JOINT ASSEMBLY:
An assembly in which a metal ring of oval or octagonal cross-section fits into
machined grooves in mating flange faces.
Generally used in high pressure, high temperature service.
ROTARY SLIDE VALVE:
A valve in which a rotation of internal parts regulates flow by opening and
closing a series of segmental ports.
ROTARY VALVE:
A spherical plug valve in which the plug, which rotates through 90°.

S.
SAFETY VALVE:
A self-actuated quick opening valve used for fast relief of excessive
pressures.
SCREWED BONNET:
A bonnet which screws into the valve body.
SCREWED END:
Type of end on valve, fitting or pipe which is joined by threaded connections.
SCREWED-IN BONNET:
See SCREWED BONNET.
SCREWED STUFFING BOX:
Another term for PACKING BOX ASSEMBLY.
SEAT:
That portion of a valve against which the plug, disc, or gate presses to
effect shut-off.
SEAT BUSHING:
Same as SEAT RING. SEAT INSERT: Same as SEAT RING.
SOCKET OR BUTT WELDING ENDS:
A type of end used on valves for mating with pipe. Final Joint is welded.
SOCKET WELDED:
A valve or fitting which slips over the end of pipe and is made pressure
tight by welding.
SOLENOID VALVE:
A valve operated by an electrical solenoid.
SOLID WEDGE DISC:
A disc or wedge of one piece
(see "Gate Valve" section of this guide for descriptive information).
S F:
An abbreviation for Steam Pressure. A number following the abbreviation is
the maximum non-shock operating pressure in psi at a given temperature.
SPECTACLE VALVE:
A parallel slide valve.
STEM PACKING:
The material placed around the valve stem in the packing gland to prevent
external leakage.
STOP CHECK OR NON-RETURN VALVE:
A valve which automatically closes when flow reverses and which can be
screwed down into a stop or closed position.
It therefore functions as both a check and a block valve.
SWING CHECK VALVE:
A valve which has a swinging disc that opens with the
pressure of the flow and closes automatically when the pressure drops.

T.
TEMPERATURE REGULATING VALVE:
For controlling fluid temperature in a system.
THERMOSTATIC MIXING VALVE:
A valve which combines temperature.
THROTTLE VALVE:
A non tight closing butterfly valve.
THROTTLING:
Regulation of flow through a valve.

V.
VALVE BODY:
The main part of a valve which contains the passageway for the flow medium
and the seating surfaces for the plug, disc, or gate which controls the amount
of flow.
VALVE CLOSURE MEMBER:
That part of a valve which is positioned to close, open, or to control the
amount of flow.
VALVE OPERATOR:
The valve part or parts through which forces are applied to move or position
the seats.
VALVE OPERATOR, MANUAL:
A valve operator consisting of a hand lever, wheel or other manual device.
VALVE OPERATOR, MECHANICAL:
A valve operator consisting of a cam, lever, roller, screw, spring, gear,
or other mechanical device.
VALVE, PRESSURE REDUCING:
A control valve whose primary function is to limit outlet pressure.
VALVE PORT:
A controllable opening between passages that can be closed, opened
or varied. Sometimes refers to the inlet or outlet openings of the valve.
VALVE, SHUT-OFF:
A valve designed to operate fully open or fully closed, and not at
intermediate positions.
VENTURI THROAT VALVE:
A valve which has a reduced opening across the seat which is smaller
than the port diameter.
V PORT PLUG:
A type of valve plug which provides an orifice in the shape of the
letter V; has good throttling characteristics.

Y.
YOKE:
That part of a valve which connects the actuator to the valve body.

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