| 3A |
Symbol for 3A Sanitary Standards Symbol Administrative Council. The
3A Sanitary Standard was created by the dairy industry as a voluntary
benchmark for product performance and safety. |
| ABS |
Acrylinitrile-butadiene-styrene - Themoplastic resin with excellent
resistance to acids, bases, salts and some solvents. |
| ANSI |
American National Standards Institute, Inc. |
| ASME |
American Society of Mechanical Engineers |
| ASTM |
American Society for Testing and Materials |
| Acme Thread |
A flat grooved helical ridge on a nut or bolt |
| Anneal |
Stress relief of stainless steel, a heat treatment to remove the
stresses generated in forming and welding operations. Done correctly,
parts are processed to provide minimum residual stresses and full
corrosion resistance. |
| B |
|
| Bevel Seat Ferrules |
A set of plain and externally threaded bushings (male and female,
respectively) with matching bevel angles that produce a leak-proof seal
when connected with a hex union nut. |
| Bright Anneal |
Annealing in a protective medium to prevent discoloration of the
surface. |
| Bright Annealed Finish |
A silvery satin surface, approximately the mill
finish of stainless
steel. |
| Buna |
Synthetic rubber, a copolymer of acrylonitrile and butadiene. |
| Burst Pressure |
The pressure at which rupture occurs.
|
| C |
|
| Cavitation |
When the NPSH required by the pump is greater than the NPSH
available by the system, cavitation occurs. Vapor is formed and moves
along the stream. The vapor bubbles collapse when they reach regions or
higher pressure on their way through, the pump cavities are forming in
the liquid being pumped. |
| Clamp |
A device used to join mechanical parts, fittings, ensuring a quick
leak-proof connection and enabling easy take down. |
| Cold Flow |
Continued deformation or movement of rubber or PTFE under stress. |
| Compression Set |
The deformation that remains in rubber or PTFE after it has been
subjected to and released from stress such as a clamp. The longer the
stress is maintained, the more definitive the deformation. |
| D |
|
| DA |
Double acting. |
| Double-Acting Pneumatic Actuator |
Any pneumatic actuator which uses air to drive the actuator output
shaft in both the open and closed direction. The air supply is piped to
one side of a piston-drive or a diaphragm while the air contained on the
opposing side is exhausted. |
| DPDT |
Double pole-double throw. |
| Durometer |
Instrument used for measuring the hardness of rubber. |
| Durometer hardness |
A numerical value which indicates the resistance to indentation of
the blunt indentor of the durometer. |
| E |
|
| EPDM |
Ethylene Propylene Diene Monome, a synthetic rubber. |
| Elastomer |
Any of various elastic substances resembling rubber. |
| Electric Actuator |
An electro-mechanical device used to open and close or modulate a
valve. |
| Electric Failsafe Actuator |
Electrically driven actuator that
contains an internal spring to close the valve on loss of power. |
| Encapsulation |
The enclosing of material by an
encapsulant for protective purposes. |
| F |
|
| Fail-Closed |
Spring return pneumatic actuator is
applied to the valve such that the spring will drive the valve to the
close position upon loss of air (may be termed air-to-open). |
| Fail-Open |
Spring return pneumatic actuator is
applied to the valve such that the spring will drive the valve to open
position upon loss of air (may be termed air-to-close). |
| Ferrule |
A bushing used to secure a tube joint. A
special bushing designed for welding to the end of tubing. Two ferrules
and a gasket make a leak-proof connection when used with the
complimentary clamps. |
| Fitting |
A small part of an apparatus. See our
fitting numbering
guide. |
| Fluorocarbon |
Elastomer known as VitonŽ, a registered
trademark of DuPont. |
| Friction Loss |
The reduction of water pressure which
occurs as water travels over distance and through and kind of
restriction. |
| G |
|
| Gasket |
A seal used between matched machine
parts to prevent escape of a gas or fluid. Special seals fit between the
ferrules on the fittings, which are then clamped together, compressing
the seal and making a leak-proof joint. |
| H |
|
| Hex Union Nut |
An internally acme-threaded six-sided
connector used to assemble bevel seat fittings. |
| I |
|
| ISO5211 |
International standard for actuator and
valve interface. |
| Internal Expansion (IX) |
A plug (or bullet) is pulled through a
stem or set of blades (fingers) increase the stem I.D. to the plug O.D.
or a predetermined setting when using expansion blades. This forces the
stem serrations into the hose tube and the hose cover into the
serrations of the ferrule. |
| L |
|
| Laminar Flow |
The flow of a fluid when each particle
of the fluid follows a smooth path, paths which never interfere with one
another. One result of laminar flow is that the velocity of the fluid is
constant at any point in the fluid. |
| M |
|
| Manual Over-ride |
Any mechanical device by which an
automated valve may be manually operated. On smaller actuators, this may
simply be wrench flats on the output shaft of the actuator. Larger
actuators may require a more sophisticated system, such as declutchable
hand wheels, or manual gears. |
| Maximum-Shut-Off Pressure |
The pressure of the media flowing into
the valve against which the valve will have to close. |
| Media |
The material flowing through the valve. |
| MTR |
Material Test Report |
| Modulating Service |
When the valve is being used to throttle
or regulate the rate of flow by being positioned at varying positions
between open and closed. |
| N |
|
| NAMUR |
International Standard of Interface for
Actuator Connections |
| NEMA 4 |
Weather-proof enclosure suitable for
indoor/outdoor applications to protect from windblown dust, rain or
hose-directed water. |
| NEMA 4x |
Offers the same protection as Nema 4
with the addition of corrosion resistance. |
| NEMA 6 |
Enclosure that may be submerged up to
six feet for 30 minutes. |
| NEMA 7 |
Enclosure for hazardous locations must
be capable of withstanding an internal explosion of gases so as not to
ignite an external gas-air mixture. |
| NEMA Rating |
National Electrical Code Ratings for
electrical component enclosures. |
| Neoprene |
Synthetic rubber, chemically and
structurally similar to natural rubber. |
| Nominal Size |
A dimensional value assigned for the
purpose of convenient designation. |
| O |
|
| On-Off Service |
When the valve is being used to cycle to
the full open or full closed position. |
| Operating Pressure |
The pressure at which the system
functions. |
| P |
|
| Pneumatic Actuator |
An air operated mechanical device used
to open and close or modulate a valve. The actuator, which is mounted to
the valve by a bracket and coupled to the stem, is designed to convert
air pressure into mechanical force sufficient to operate the valve. |
| Polypropylene |
A lightweight synthetic plastic. |
| PSI |
Pounds per square inch. |
| PSIG |
Pounds per square inch gauge. |
| PTFE |
Tetrafluoroethylene, DuPont's TeflonŽ,
is a high performance engineering plastic that is not wet by many
liquids. |
| S |
|
| Silicone |
Dimethyl silicone, a synthetic rubber. |
| SPDT |
Single pole double throw. |
| Spring-Return Pneumatic
Actuator |
Any pneumatic actuator which contains a
single coil spring or group of coil springs to oppose the movement of a
piston. As air moves the piston or diaphragm, the spring is compressed.
When the air supply is discontinued and exhausted, the spring extends
and drives the piston in the opposite direction. |
| SPST |
Single pole single throw. |
| Stem Torque |
The force required at the valve stem to
open or close the valve. Torque is expressed in inch pounds or foot
pounds. |
| Supply Pressure |
The plant air supply pressure available
to operate a pneumatic actuator. |
| Surge |
A rapid rise and decrease of internal
pressure. |
| T |
|
| Torque |
A twisting or turning force usually
measured in inch pounds or foot pounds. |
| Tube |
A hollow cylinder especially one that
conveys a fluid. For sanitary applications, a thin wall is implied. |
| Tube Fitting |
A length of tubing formed into a usable
shape either welded to an apparatus or welded to ferrules for use in an
apparatus. |
| Turbulent Flow |
Irregular flow that is characterized by
tiny whirlpool regions. The velocity of this fluid is NOT constand at
every point. |
| W |
|
| WOG |
Water, Oil, Gas. Pressure rating for
valves handling these products. |
| Welding |
Join two or more pieces of material by
applying heat to produce a localized union through fusion across the
interface. For sanitary fittings, a ferrule is attached to the ends of a
tube fitting by TIG welding without the addition of filler metal. Tube
fittings can then be joined with clamps and gaskets to form parts of a
system. |
