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 sanitary safety. The standard, collaboratively developed by a group of processors, suppliers, regulatory officials and sanitation specialists, is accepted by federal, state and local regulatory authorities. Our products have earned the 3A symbol through third party verification. This assessment makes certain each product conforms in all aspects to the published standards. Dixon Sanitary is proud to be a participant in the 3A program.

3A Finish
Product surface finish equivalent to 150 grit or better OD, and 180 grit or better ID. A minimum of Ra 32 micro inch (0.8 micron) is indicated.

(Acrylicnitrile-butadiene-styrene) a thermoplastic resin with an excellent resistance to acids, bases, salts and some solvents. It is heat-resistant to 230°F.

Alternating current.  The form in which electricity is delivered to businesses and residences.


American National Standards Institute, Inc.

American Society of Mechanical Engineers

American Society for Testing and Materials

Acme Thread
A flat grooved helical ridge on a nut or bolt. This thread typically has a 29° included angle and is used on bevel seat and John Perry fittings.

Connects the pump fluid end to the motor

Affinity Laws
Used to predict how capacity, head and horsepower are affected by changes in the centrifugal pump impeller diameter or impeller speed.

Ambient Temperature
The temperature at a point or area expressed as an average of the surrounding areas or materials.  Ambient surface temperature is generally given to be 70°F to 80°F – an average of daily and seasonal variations.

Stress relief of stainless steel, a heat treatment to remove the stresses generated in forming and welding operations. This heat treatment is best done under a controlled atmosphere or vacuum to maintain the mill finish. The fittings are not quenched, as in solution annealing; this would reintroduce residual stresses. Done correctly, parts are processed to provide minimum residual stresses and full corrosion resistance.

Atmospheric Pressure
Force per unit area exerted against a surface by the weight of the air above that surface.  At sea level, atmospheric pressure is 14.7 PSI.

Automatic Welding
Welding with equipment that performs the welding operation without adjustment of the controls by a welding operator.  The equipment may or may not perform the loading and unloading of the work  (see also machine welding).

BEP Best Efficiency Point
The point where the power coming out of the pump (water horsepower) is the closest to the power coming into the pump (brake horsepower) from the motor.  This is also the point where there is no radial deflection of the shaft caused by unequal hydraulic forces acting on the impeller.  Referred to as the sweet spot on the curve.

Brake Horsepower.  The actual amount of horsepower being consumed by the pump as measured on a pony brake or dynamometer.  This is not the horsepower used by the motor or driver.

Bevel Seat Ferrules
A set of plain (male) and externally threaded (female) bushings with matching bevel angles that produce a leak-proof seal when connected with a hex union nut. The threads used are Acme form.

The creation of a product utilizing a living organism

Bioprocessing Equipment
Equipment, systems or facilities used in the creation of products utilizing living organisms

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.

Synthetic rubber, a copolymer of acrylonitrile and butadiene.

Burst Pressure
The pressure at which rupture occurs.

Counter clockwise

The NEMA standard for motor mounting dimensions.

The flow rate (in US gal/min) of pure water at 60°F passing through a valve when the valve is fully opened and the pressure differential between the two ends of the valve is 1 PSI.
     •  V = max. flow (in US gal/min)
     •  G = specific gravity (1 for water)
     •  P1 = inlet side pressure (psi)
     •  P2 = outlet side pressure (psi)


Flow rate normally measured in gallons per minute (GPM).

A common mechanical seal face material chemically inert to most fluids with the exception of oxidizers, bleaches, halogens and a few other fluids.

When the NPSH required by the pump is greater than the NPSH available by the system, cavitation occurs. Vapor is formed and moves along with the stream. These vapor bubbles or "cavities" collapse when they reach regions of higher pressure on their way through the pump cavities. When these cavities form at the suction of the pump, several things happen all at once.
     •  We experience a loss in capacity.
     •  We can no longer build the same head (pressure)
     •  The efficiency drops.
     • The cavities or bubbles will collapse when they pass into the higher regions of pressure causing noise, vibration, and damage to many of the components.

Metric unit of viscosity

The kinematic unit of viscosity.  Viscosity in centipoise divided by the liquid density at the same temperature gives kinematic viscosity in centistokes.

Centrifugal Pump
Moves liquid with centrifugal force.

A hard, chemically inert seal face material that has very high compressive resistance.

A device used to join mechanical parts, fittings, ensuring a quick leak-proof connection and enabling easy take down.

Clean-In-Place (CIP)
Internally cleaning a piece of equipment without relocation or disassembly.  The equipment is cleaned but not necessarily sterilized.  The cleaning is normally done by acid, caustic or a combination of both with water-for-injection (WFI) rinse.

Close Coupled
The pump impeller is mounted directly to the motor shaft or stub shaft that is mounted directly on the motor shaft.  There is no separate bearing case.

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.

Controlled Sulfur
In weld ends of 316L materials used in BPE installations, the sulfur content must be between .005% and .017% to assure better orbital welding.

A chemical or electrochemical interaction between a metal and its environment, which results in changes in the property of the metal.  This may lead to impairment of the function of the metal, the environment and/or the technical system involved.

See Hertz

Double acting

Direct current.  The movement of electrical charge is only in one direction.

Double pole-double throw, a type of limit switch.

Dead Head
The condition of a centrifugal pump running with a closed discharge line.

Dilatent Fluid
Viscosity increases with shear.

Discharge Head
The outlet pressure of a pump.

Any pneumatic actuator, which uses air to drive the actuator, output shaft in both the CW and CCW directions. 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.

Dry Running
Occurs when a pump is running with insufficient or no fluid in the pump.

An instrument for measuring the hardness of rubber.

Durometer Hardness
A numerical value, which indicates the resistance to indentation of the blunt indentor of the durometer.

Dynamic Head (System Head)
A moving fluid exerts a pressure higher than the static pressure due to the kinetic energy of the fluid.

Ethylene propylene diene monomer, a synthetic rubber.

Power out of the pump divided by power into the pump.
            Efficiency Formula: TDH X GPM / HP X 3960

Any of various elastic substances resembling rubber.

Elastomeric Material
A material that can be stretched or compressed repeatedly and, upon immediate release of stress, will return to its approximate original size.

Electric Actuator
An electro-mechanical device used to open and close or modulate a valve. The actuator (which is mounted and coupled to the valve in similar fashion as the pneumatic actuator), operates the valve using an electric motor driving a gear train. While the basic function of the electric actuator is similar to the pneumatic, there are distinct differences in the application and flexibility of the two types, and these differences should be considered to select the proper type.

Electric Failsafe Actuator
Electrically driven actuator that contains an internal spring to close the valve on loss of power.

A controlled electrochemical process utilizing acid electrolyte, DC current, anode and cathode to smooth the surface by removal of metal.

The enclosing of material by an encapsulant for protective purposes. In a ball valve, the ball is encased in PTFE, preventing the material flowing through the valve from getting behind the ball causing contamination problems.

Eye of the Impeller
The center of the impeller where the fluid enters.

A DuPont manufactured elastomer widely used in the sealing industry.  FKM is the generic equivalent.

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 the open position upon loss of air (may be termed air-to-close).

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.

A small part of an apparatus (may be detachable).

Flooded Suction
When the liquid source is higher than the pump and the liquid flows to the pump by gravity.  Preferable for centrifugal pump installations.

See capacity

Flow Coefficient (Cv)
The flow in U.S. gallons of water (at 60°F) that will pass through the valve in one minute with a differential pressure across the valve of 1 PSI.

Fluid End
The portion of the pump that comes in contact with the fluid being pumped.

Elastomer known as FKM a registered trademark of DuPont.

Polymer material having a carbon chain either partially or completely bonded to fluorine atoms. FKM (FKM) and PTFE are examples of this material type.

Foot Valve
A type of check valve.  Used at the point of the liquid intake to retain liquid in the system, preventing the loss of prime when the liquid source is lower than the pump.

See C-Face

Friction Head
The pressure needed to overcome the resistance to the flow in the pipe and fittings.

Friction Loss
The resistance to flow as a liquid is moved through a pipe (or valve); due to viscous shear stresses within the liquid and resulting turbulence.

Gallons per minute

Gas Tungsten-Arc Welding (GTAW)
An arc welding process that produces coalescence of metals by heating them with an arc between a tungsten (non-consumable) electrode and the work. Shielding is obtained from a gas or gas mixture.  (This process is sometimes called TIG welding, a non-preferred term.)  GTAW may be performed by adding filler material to the weld or by a fusion process in which no filler is added.

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.

Hard Face
A seal face either rotating or stationary.  The most common materials are silicon carbide, ceramic and tungsten carbide.

The equivalent height of the liquid. 20°C water is used as the standard where 33.9ft of water equals one atmosphere (14.7psi).  The pressure in a column of liquid. Pressure will increase as the height of the column increases.  Head refers to the height in feet: pressure refers to the PSI.  Centrifugal pump discharge is measured in head.

Heat Number
An alphanumeric identification of a stated tonnage of metal obtained from a continuous melting in a furnace.

Heat-Affected Zone
That portion of the base metal that has not been melted, but whose microstructure or mechanical properties have been altered by the heat of welding or cutting.

Frequency (cycles per seconds)

Hex Union Nut
An internally acme-threaded six-sided connector used to assemble bevel seat fittings.

Unit for measurement of power or rate of work.  One horsepower = 33,000 foot pounds per minute.

Hygienic Clamp Joint
A tube outside diameter union consisting of two neutered ferrules having flat faces with a concentric groove and mating gasket that is secured with a clamp, providing a non-protruding, recessless product contact surface.

International standard for valve and actuator interface.

A rotor or rotor blade attached to the end of the stub shaft imparting energy from the motor to the fluid being pumped.

Internal Expansion
A plug (or bullet) is pulled through a stem or a set of blades (fingers) increase the stem I.D. to the plug O.D. or a predetermined setting when using expansion blades (fingers). This forces the stem serrations into the hose tube and the hose cover into the serrations of the ferrule.

Kinetic Energy
Created by a centrifugal pump when the velocity of the fluid is accelerated to the outer rim of the impeller.  The amount of kinetic energy given to the fluid corresponds to the velocity at the impeller vane tip.  The faster the impeller revolves or the bigger the impeller, the greater the energy given to the fluid.  This kinetic energy is then harnessed and slowed by the resistance created by the pump volute.

Laminar Flow
The flow of a fluid when each particle of the fluid follows a smooth path, paths that 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.

Lubricant Any fluid that will maintain a film thickness of one micron or more at its operating temperature and load.

Material Test Report

Machine Welding
Welding with equipment that performs the welding operation under the constant observation and control of a welding operator.  The equipment may or may not perform the loading and unloading of the works. (see also automatic welding).

Manual Override
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.

Manual Welding
Welding in which the entire welding operation is performed and controlled by hand.

The pressure of the media flowing into the valve against which the valve will have to close.

Of or pertaining to a weld bead that deviates from side to side across the weld joint rather than tracking the joint precisely. Note the controlled sulfur content in BPE weld material.

Mechanical Seal
A positive sealing device used to seal all fluids.  Consists of two basic parts, a rotating element attached to the pump shaft and a stationary element attached to the pump casing. Each of these elements has a highly polished sealing surface.  The polished faces of the rotating and stationary elements come into contact with each other to form a seal that prevents leakage along the shaft.

The material flowing through the system.

Modulating Service
Proportional positioning of a valve between the open and closed positions, used for flow control processes.

International Standard of Interface for Actuator Accessory Connections.

Weather-proof enclosure suitable for indoor/outdoor applications to protect from windblown dust, rain or hose-directed water.

Offers the same protection as Nema 4 with the addition of corrosion resistance.

Enclosure that may be submerged up to six feet for 30 minutes.

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.

Net positive suction head available is the amount of fluid pressure you have at the suction side of the pump due to atmospheric pressure, pressurized tank or other means.

Net positive suction head required is the amount of fluid pressure required at the suction to prevent cavitation. This requirement is found on pump curves produced by each pump manufacturer.

Synthetic rubber, chemically and structurally similar to natural rubber.

A surface void anomaly caused by material removal or compression from the surface, whose bottom surface is usually irregular.

Nominal Size
A dimensional value assigned for the purpose of convenient designation, used for pipes.

Net Positive Suction Head
Amount of energy in the liquid at the pump datum. It must be defined to have a meaning, as either available or required NPSH.

Open Drip Proof motor enclosure

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 system functions. Also known as Working Pressure.

Orbital Welding
Automatic or machine welding of tubes or pipe in-place with the electrode rotating (or orbiting) around the work.  Orbital welding can be done with the addition of filler material or as a fusion process without the addition of filler.

Pounds per square inch

Pounds per square inch gauge

Tetrafluoroethylene, a high performance thermoplastic polymer that has excellent dielectric strength, chemical and temperature resistance.

Removal of exogenous iron or iron from the surface of stainless steels and higher alloys by means of a chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination and enhance the formation of the passive layer.

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.

To make smooth and shiny by rubbing. Fittings may be machine polished to a 180 grit finish. Polish is ID, OD, or both per customer request.

A lightweight synthetic plastic.

Positive Displacement Pump
A pump that causes a fluid to move by trapping a fixed amount of it then forcing (displacing) that trapped volume into the discharge pipe.

The force per unit area applied on a surface in a direction perpendicular to that surface.

Pressure Head
Must be considered when a pumping system either begins or terminates in a tank which is under some pressure other than atmospheric. The pressure in such a tank must first be converted to feet of liquid. A vacuum in the suction tank or a positive pressure in the discharge tank must be added to the system head, whereas a positive pressure in the suction tank or vacuum in the discharge tank would be subtracted. The following is a handy formula for converting inches of mercury vacuum into feet of liquid.
                                             Vacuum, in. of Hg X 1.13 / Vacuum, ft of liquid = Sp. Gr.

The above forms of head, namely static, friction, velocity, and pressure, are combined to make up the total system head at any particular flow rate.

Pressure Rating
Pressure at which a system is designed to operate, allowing for applicable safety factors.

A charge of liquid required beginning the pumping action of centrifugal pumps when the liquid source is lower than the pump.

An instrument for the measurement of the degree of surface roughness.

Log of the arithmetic mean of the surface profile.

Revolutions per minute

Single pole double throw, a type of limit switch.

Single pole single throw, a type of limit switch.

Standard conditions for temperature and pressure. In physical sciences, STP, are standard sets of conditions for experimental measurements, to allow comparisons to be made between different sets of data. National Institute of Standard and Technology's (NIST) version is a temperature of 20°C (293.15 K, 68°F) and an absolute pressure of 101.325 kPa (14.696 PSI, 1 atm).

Sanitary (hygienic) Weld
Generally considered to be a groove weld in a square butt joint made by the GTAW (or plasma) process as a fusion weld without the addition of filler material.  A sanitary weld must be completely penetrated on the weld ID, with little or no discoloration due to oxidation and be otherwise without defects that would interfere with maintenance in a clean and sterile condition.

A thermoplastic elastomer, a rubber-like material that complies with FDA requirements.

Dimensional standard for pipe as defined by ASTM.

Seal Face
Surface point on which a seal is achieved.

Service Temperature
The maximum and minimum temperature of the media.

Shut-Off Head
The maximum head that a pump can generate.

Silicon Carbide
Synthetic mineral of silicon and carbide.  It is used in abrasives, refractories, ceramics and numerous high performance applications.

Dimethyl silicone, a synthetic rubber.

Heat process in which powdered metal particles are heated to near melting point, fusing the metal granules together.

Specific Gravity
A measure of the weight of a liquid in relation to that of water.  If the liquid in question will float on water then the specific gravity will be less than one and if the liquid will sink when mixed with water the specific gravity will be greater than one.

Any pneumatic actuator which contains a single coil spring or group of coil springs to oppose the Pneumatic Actuator 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. This type of actuator is normally used for applications where it is necessary for the valve to move to the open or close position upon loss of air supply, whether by design or by system failure.

Static Discharge Head
The vertical distance in feet between the pump center line and the point of free discharge or the surface of the liquid in the discharge tank.

Static Head
The pressure at any point in a liquid can be thought of as being caused by a vertical column of the liquid which, due to its weight, exerts a pressure equal to the pressure at the point in question. The height of this column is called the "static head" and is expressed in terms of feet of liquid.

Stem Torque
The force required at the valve stem to open or close the valve. Torque is expressed in inch pounds or foot pounds.

Suction Head
Exists when the source of supply is above the center line of the pump. Thus the static suction head is the vertical distance in feet from the center line of the pump to the free level of the liquid to be pumped.

Suction Lift
Exists when the source of supply is below the centerline of the pump. Thus the static suction lift is the vertical distance in feet from the centerline of the pump to the free level of the liquid to be pumped.

Supply Pressure
The plant air supply pressure available to operate a pneumatic actuator.

Surface Finish
All surfaced as defined by Part SF of the current ASME BPE Standard and/or the owner/user or manufacturer and referred in Ra µin. or µm.

Surge (also known as water hammer)
A rapid rise or decrease of internal pressure. Surge conditions typically occur, but are not limited to, start and stop sequences.

System Curve
A description of what the pump is required to perform.  The pump will pump where the system curve intersects the pump curve.

System Head
The head caused by friction in the piping valves and fittings.

Total dynamic head.  A combination of the suction head and the head being produced by the pump.  Discharge reservoir pressure head + static discharge head + velocity head at pump discharge + total friction head in discharge line.

Totally Enclosed Fan Cooled motor enclosure.

Totally Enclosed Non Ventilated motor enclosure.

Thixotropic Fluid
Viscosity thins with shear.

A twisting or turning force. Usually measured in inch pounds (in. lbs.) or foot pounds (ft. lbs.)

Total Dynamic Discharge Head (hd)
The static discharge head plus the velocity head at the pump discharge flange plus the total friction head in the discharge line. The total dynamic discharge head, as determined on pump test, is the reading of a gauge at the discharge flange, converted to feet of liquid and corrected to the pump centerline, plus the velocity head at the point of gauge attachment.

Total Dynamic Suction Head (hs)
The static suction head plus the velocity head at the pump suction flange minus the total friction head in the suction line. The total dynamic suction head, as determined on pump test, is the reading of the gauge on the suction flange, converted to feet of liquid and corrected to the pump centerline, plus the velocity head at the point of gauge attachment.

Total Dynamic Suction Lift (hs)
The static suction lift minus the velocity head at the pump suction flange plus the total friction head in the suction line. The total dynamic suction lift, as determined on pump tests, is the reading of a gauge on the suction flange, converted to feet of liquid and corrected to the pump centerline, minus the velocity head at the point of gauge attachment.

Total Head (H) or Total Dynamic Head
The total dynamic discharge head minus the total dynamic suction head or plus the total dynamic suction lift.
                                                                      TDH = hd + hs (with suction lift)
                                                                      TDH = hd - hs (with a suction head)

Total Static Head
The vertical distance in feet between the free level of the source of supply and the point of free discharge or the free surface of the discharge liquid.

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.

A piece or length of tube.

Tumble Polish Surface
A uniform finish applied by vibratory equipment to stainless steel, varying from matte grey to bright, depending on media used. This process may cause work hardening on the surfaces.

Tungsten Carbide
A common hard face seal material available in several grades depending upon hardness and corrosion resistance.  Cobalt and nickel are the two most common binders.

Turbulent Flow
Irregular flow that is characterized by tiny whirlpool regions. The velocity of this fluid is definitely not constant at every point.

Variable Frequency Drive. Used to vary the frequency going into a motor, thus varying the speed at which the motor runs.

Vapor Pressure
Below this pressure the liquid being pumped will vaporize.

The fluid passes from a liquid to a gaseous state.

A measurement of the speed of the liquid in the system; Velocity = distance/time.

Velocity Head (hv)
The energy of a liquid as a result of its motion at some velocity V. It is the equivalent head in feet through which the water would have to fall to acquire the same velocity, or in other words, the head necessary to accelerate the water. Velocity head can be calculated from the following formula:
                                            H =               V2 / 2g
                                            where g = 32.2 ft/second-2
                                                          V = liquid velocity in feet per second

The velocity head is usually insignificant and can be ignored in most high head systems. However, it can be a large factor and must be considered in low head systems

Resistance to flow.  Internal friction of a liquid tending to reduce flow.

Volute (casing)
Casing surrounding the pump impeller.  The volute converts velocity energy to pressure energy.

Water Horse Power.  The calculated horse power coming out of the pump.
                                                 WHP  =  head x gpm / 3960

Water, Oil, Gas. Pressure rating for valves handling these products. This does not include steam.

Washdown Duty
Motor enclosure that is suitable for a liquid washdown atmosphere.

Water Hammer
See surge

Undulations or rippling of the surfaces.

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.

Work (Strain, hardening)
An increase in hardness and strength caused by plastic deformation at temperatures below the annealing ranges. Work hardening will increase the cost of polishing because of increased hardness and can increase the chance of corrosion in stainless steels.

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