Pump technology for interested readers.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

 

Allowable operating range

The range of flows or heads at the specified operating conditions of the pump supplied is limited by cavitation, heating, vibration, noise, shaft deflection and other similar criteria. This range is defined by the manufacturer. The upper and lower limits of the range are denoted by maximum or minimum continuous flow.

 

Allowable temperature range of the pump

The temperature range from minimum through maximum allowable continuous temperature for which the equipment (or any part to which the term refers) is suitable when handling the specified operating fluid at the specified operating pressure.
Unit: ° C

 

Allowable working

The limiting values and/or ranges of conditions at which the pump unit can be operated, owing to the material and the design and execution.

 

Anti-clockwise rotation

The direction of rotation in which the shaft is seen to be turning in an anti-clockwise direction, when viewing the drive-end of the shaft.
Symbol: cc
Unit: -

 

Atmospheric pressure

The mean absolute pressure of the atmosphere measured at the place of installation of the pump.
Symbol: pamb
Unit: bar, Pa

 

Auxiliary connections

Connections provided for flushing, by-pass, pressure balance, or other similar purposes.

 

Axial split

Refers to casing joints that are parallel to the shaft centerline.



B

 

Balancing rate of flow

The rate of flow which is extracted to activate a balance device.
Symbol: QB
Unit: m3/s, m3/h, l/s, l/h

 

Barrier liquid

Liquid introduced between pressurized double mechanical seals to completely isolate the pump process liquid from the environment.

 

Basic design pressure

Pressure derived from the permitted stress at 20 ° C of the material used for the pressure-containing parts.
Symbol: pN

 

Buffer liquid

Liquid used as a lubricant or buffer between unpressurized dual (tandem) mechanical seals.

 



C

 

Cinematic viscosity

Ratio of the dynamic viscosity to the density of the pumped liquid.
Symbol: ν
Unit: m2/s, mm2/s, cSt

 

Clockwise rotation

The direction of rotation in which the shaft is seen to be turning in a clock-wise direction when viewing the drive-end of the shaft.
Symbol: c
Unit: -

 

Close coupled

A coupling arrangement in which the motor is supplied with a flange adaptor which mounts directly to the casing or body of the pump, permitting the use of a single or solidly coupled shaft.

 

Component

An assembly of parts put together to fulfil a specific identifiable function independently or in combination with other parts/components.

 

Conditions

All parameters (for example temperatures, pressures) determined by the application and the pumped liquid which affect the function and performance of the system.

 

Corrosion allowance

That portion of the wall thickness of the parts wetted by the pumped liquid in excess of the theoretical thickness required to withstand the pressure limits by the maximum allowable working pressure.

 

Counter-clockwise rotation

The direction of rotation in which the shaft is seen to be turning in an anti-clockwise direction, when viewing the drive-end of the shaft.
Symbol: cc
Unit: -

 

Coupling

The link by which energy is transferred between the driver and the pump. The energy transmission may be mechanically, hydraulically or magnetically.

 

Coupling service factor

A factor which is to be multiplied by the nominal torque of the driver in order to get a fictitious torque which makes due allowance for cyclic torque fluctuations from the pump and / or its driver and therefore ensures satisfactory coupling life.

 

Customized Pumps

In the engineering industry more often optimized solutions are developed that cannot be covered with standard components. Special modifications are required for the pumps. This concerns the mounting installation, the drives and sealing systems as well as the operating conditions or standardization efforts. By means of an ingenious and proven modular construction system EDUR is in a position to supply adaptations and customized constructions in a flexible and short-term way.

 


D

 

Density

Mass per unit volume at a stated temperature.
Symbol: ρ
Unit: kg/m3

 

Differential pressure

The gain in total head between the pump inlet and pump outlet expressed in pressure units.
Symbol: p1-2
Unit: bar, Pa

 

Double flow

Impeller with double entry flow direction.

 

Drive

Machine supplying mechanical energy.

 

Drive power input

The power absorbed by the pump drive. It is also common practice to use P1 instead of Pmot. In these cases the subscript "1" refers to the electrical input to the motor rather than to the inlet of the pump.
Symbol: Pmot
Unit: W, kW

 

Drive rated power output

The continuous drive power output permitted under defined conditions.
Symbol: Pmot u r
Unit: W, kW

 

Duty Point

The target values of the total head of the pump and the rate of flow for which a pump is designed or selected.

 

Dynamic viscosity

Ratio of the shear stress to the shear velocity acting in a liquid subjected to a plane shear motion.
Symbol: η
Unit: N x s/m2, mPas, cP



E

F

Face runout

The total axial deviation indicated at the outer radial face of the shaft seal casing by a device attached to and rotated with the shaft when the shaft is rotated manually in its bearings in the horizontal position.



G

 

Gas content

The proportion of gaseous substance in the liquid to be pumped either as a contaminant, or as vapour from the main body of liquid.
Symbol: -
Unit: % by wt., % by vol.

 

Gauge pressure at point x

The reading on a pressure measuring instrument attached to an observed point x.
Symbol: pxM
Unit: bar, Pa

 

Guarantee point

The operating performance of the pump which the supplier guarantees to be achieved under specified conditions. The guarantee point may be defined as:

- total head at a specified rate of flow
- rate of flow at a specified total head
- pump or motor power input
- pump or overall efficiency
- (NPHSR)
- other points on the pump H(Q)-curve for rotodynamic pumps.



H

 

Head

The energy per unit mass of fluid divided by gravitation acceleration. The head may also be considered as the height of a column of fluid at rest giving a pressure onto its bottom surface equivalent to the energy per unit mass being acted upon by the acceleration due to gravity.
Symbol: H
Unit: m

 

Head at peak point

The highest total head developed by a pump when this does not occur at a zero rate of flow.
Symbol: Hsch
Unit: m

 

Hydraulic efficiency

The proportion of pump power input, P, which is delivered as pump power output after satisfying the mechanical losses, losses resulting from friction due to the relative motion of internal surfaces and internal leakage.
Symbol: ηh
Unit: -

 

Hydrostatic test pressure

The gauge pressure to which a part, component or pump is subjected for the purpose of strength or leak testing.
Symbol: ptest
Unit: bar, Pa



I

 

Industry-Bloc pump

Type NUB NUBF
All-purpose single-stage circulation pumps in compact design for the use in water supply, cooling and refrigeration technology, air-conditioning, filtration, shipbuilding, apparatus engineering, energy technique, plastics processing and general machine engineering. Wide range of designs with various types and material modifications for clean or slightly polluted liquids. Well-established pump type for economical, reliable and long-lasting operation.

 

Injection flush

The introduction of an appropriate (clean, compatible etc) liquid into the seal cavity from an external source and then into the pumped liquid.

 

Inlet area of the pump

The free cross-sectional area of the entry opening in the inlet connection of the pump.
Symbol: A1
Unit: m2

 

Inlet pressure of the pump

The pressure acting at the inlet area of the pump.
Symbol: p1
Unit: bar, Pa

 

Inlet rate of flow

The rate of flow passing the inlet area of the pump from the inlet side of the installation.
Symbol: Q1
Unit: m3/s, m3/h, l/s, l/h

 

Inline-Bloc pump

Type LUB
All-purpose single-stage circulation pumps in inline-design for the use in water supply, house and building technique, shipbuilding, cooling technology, machine and apparatus engineering. Space-saving alternative to standard bloc-pumps. For clean or slightly polluted liquids.

 

Installation

The arrangement of pipes, supports, foundations, controls, drives etc. into which the pump or pump unit is connected in order to achieve the service for which it was acquired.

 

Installation (NPSHA) curve

The relationship between the net positive suction head available and the rate of flow at given operating conditions and liquid.

 

Intermediate take off rate of flow

The rate of flow passing through one or more intermediate take-off points.
Symbol: Q3, 4...
Unit: m3/s, m3/h, l/s, l/h

 

Internal efficiency

The proportion of the pump power input "P" which is delivered as pump power output after satisfying the mechanical power losses.
Symbol: ηint
Unit: -



J

K

L

 

Leakage rate of flow

The rate of flow leaking from shaft seals.
Symbol: Q L
Unit: m3/s, m3/h, l/s, l/h

 

Liquid pump

A machine for the raising of liquids from a low to a high energy level for instance:
- by the effect of a force on the pumping medium
- by transferring mechanical work to the pumping medium
- by impulse exchange
- by utilizing the energy of a moving column of liquid when suddenly arrested
- by making use of the viscosity of the pumped fluid
- by the action of a magnetic field on the medium to be pumped.

 

Liquid-Ring Vacuum pump

Type GS ZB
All-purpose liquid-ring vacuum pumps in compact bloc-design for oil-free transport of dry and saturated gases in rough vacuum. Typical applications are the evacuation of suction pipe lines of large non-selfpriming pumps, suction devices, pumping stations, extrusion and downstream equipments, industrial technique and process technology.

 

Loss of head

The difference of the head at one observed point from the head at a second observed point.
Symbol: HJx-x
Unit: m



M

 

Mass rate of flow

The mass of liquid discharged from the outlet area of the pump in a given time. Losses inherent to the pump i.e. discharge necessary for

a) the hydraulic balancing of axial thrust,
b) cooling of bearings of the pump,
c) liquid seal to the packing,
d) leakage from fittings, internal leakage, etc.

should not to be reckoned in the mass rate of flow. Quantities used for other purposes, such as:

e) cooling of motor bearings,
f) cooling of gearbox (bearings, oil cooler) etc.

should be reckoned in the mass rate of flow, if they are taken from a point before the flow measuring section. Whether and how these flows should be taken into account depends upon the location of their source and relationship to the flow-measuring section.
Symbol: q
Unit: kg/h, kg/s, t/h

 

Maximum allowable casing working pressure

The greatest outlet pressure at the specified operating temperature at which the pump casing can be used. This pressure should be equal or greater than the maximum outlet pressure.
Symbol: pall w C
Unit: bar, Pa



Maximum allowable continuous speed

The highest speed at which the manufacturer will permit continuous operation.
Symbol: nmax all
Unit: min-1, s-1

 

Maximum allowable flow

Greatest rate of flow that the pump can be expected to deliver continuously without risk of internal damage when operated at the rated speed and on the liquid for which it was supplied.
Symbol: Q max all
Unit: m3/s, m3/h, l/s, l/h

 

Maximum allowable inlet pressure

The highest value of inlet pressure at which the pump or component is capable of functioning on the basis of the materials used.
Symbol: p1 max all
Unit: bar, Pa

 

Maximum allowable temperature

Highest allowable continuous temperature for which the equipment (or any part to which the term refers) is suitable when handling the specified operating fluid at the specified operating pressure.
Symbol: tmax all
Unit: ° C

 

Maximum allowable working pressure

The pressure for a component on the basis of materials used and on the basis of calculation rules at the specified operating temperature.
Symbol: pall w
Unit: bar, Pa



Maximum dynamic sealing pressure

The highest pressure expected at the shaft seals during any specified operating condition and during startup and shutdown.
Symbol: pS op
Unit: bar, Pa

 

Maximum flow

Greatest rate of flow which is expected at operating conditions.
Symbol: Qmax
Unit: m3/s, m3/h, l/s, l/h

 

Maximum head

The highest total head developed by a pump at any rate of flow.
Symbol: Hmax
Unit: m

 

Maximum inlet pressure

The highest inlet pressure to which the pump is subjected during operation.
Symbol: p1 max op
Unit: bar, Pa

 

Maximum outlet pressure

The sum of maximum inlet pressure plus maximum differential pressure derived from the furnished impeller when operating at rated conditions and density.
Symbol: p2 max op
Unit: bar, Pa



Maximum pump power input

The highest value of the pump power input at any rate of flow at any allowable operating condition.
Symbol: Pmax
Unit: kW, W


Maximum static sealing pressure

The highest pressure, excluding hydrostatic testing, to which the seal can be subjected while the pump is shutdown.
Symbol: pstat
Unit: bar, Pa


Mechanical efficiency

The proportion of the pump power input, P, available after satisfying the mechanical power losses, P Jm at given operating conditions.

ηm = (P - PJm) / P

Symbol: ηm
Unit: -


Minimum allowable continuous speed

The lowest speed at which the manufacturer will permit continuous operation.
Symbol: nmin all
Unit: min-1, s-1



Minimum allowable flow

Smallest rate of flow that the pump can be expected to deliver continuously without risk of internal damage when operated at the rated speed and on the liquid for which it was supplied.
Symbol: Q min all
Unit: m3/s, m3/h, l/s, l/h


Minimum allowable stable flow

The lowest flow at which the pump can operate without exceeding the noise and vibration limits imposed in the order.
Symbol: Q min all stable
Unit: m3/s, m3/h, l/s, l/h


Minimum allowable thermal flow

The lowest flow at which the pump can operate without its operation being impaired by the temperature rise of the pumped liquid.
Symbol: Q min all thermal
Unit: m3/s, m3/h, l/s, l/h


Minimum continuous stable flow

The lowest flow at which the pump can be operated without it adversely affecting its performance in terms of life expectancy, noise and vibrations. .
Symbol: Qmin stable
Unit: m3/h, m3/s, l/h, l/s


Minimum continuous thermal flow

The lowest flow at which the pump can operate without its operation being impaired by the temperature rise of the pumped liquid.
Symbol: Qmin thermal
Unit: m3/h, m3/s, l/h, l/s


Minimum flow

Smallest rate of flow which is expected at operating conditions.
Symbol: Qmin
Unit: m3/s, m3/h, l/s, l/h


Mixture

A combination of one or more substances remaining separate yet behaving as a single liquid for pumping.



Motor efficiency

The proportion of the drive rated power output, P mot u delivered as pump power input, P mot.

ηmot = Pmot u / Pmot

Symbol: ηmot
Unit: -

 

Multiphase

A mixture comprising a liquid together with substances in solid, or gaseous states whether due to deliberate addition or change of state due to changed conditions.

 

Multiphase pumps

Type PBU EB LBU
Horizontal centrifugal pumps for the transport of liquid-gas mixtures and for the enrichment of liquids with gases. A dispersion with very fine bubbles is being achieved. Therefore the multiphase pumps are also suitable as dynamic mixer. Some main applications are dissolved air flotation, neutralization, water treatment, bio-reactors, crude oil water separation on oil rigs and on oil fields as well as general process technology and biofuel plants.

 

Multistage

A pump with more than one impeller mounted on the same shaft and connected so as to act in series.

 

Multistage pumps

Type LBU VBU NU NHP Z
Multistage horizontal and vertical high pressure pumps in segmental type design with many variants for clean and slightly polluted liquids. Main applications are booster systems, irrigation systems, boiler feed and condensate systems, washing plants, filter technique, water treatment and hardening systems. By means of auxiliary NPSH-stages NPSH-values up to 0,5 m are being achieved.



N

Net positive suction head 3%

The NPSH required to limit to 3% the fall in the total head of the first stage of the pump.
Symbol: NPSH3
Unit: m

 

Nominal

An appropriate rounded value of a magnitude to designate a component, a unit or a device.

 

Normal flow

Rate of flow at which usual operation is expected.
Symbol: Qn
Unit: m3/s, m3/h, l/s, l/h

 

NPSH = Net positive suction head

The margin of the absolute value of the static head above the head equivalent to the vapour pressure of the liquid at the particular temperature, referred to the NPSH-datum plane.
Unit: m

 

NPSHA = Net positive suction head available

The minimum (NPSH) available at the inlet area of the pump as determined by the conditions of the installation for a specified rate of flow.
Unit: m

 

NPSHR = Net positive suction head required

The minimum (NPSH) at the pump inlet connection required to give rated or operating performance at the specified conditions. The minimum value may be determined by one of a number of different criteria such as visible cavitation, increase of noise and vibration (due to cavitation), defined head or efficiency drop or limitation of cavitation corrosion.
Unit: m



O


Operating conditions

All parameters (for example operating temperature or pressure) determined by a given application and pumped liquid.

 

Operating point

The point at which a pump will operate in an installation. It will occur at the intersection of the pump H-Q-curve and the installation HA-Q-curve.

 

Optimum head

The total head developed by the pump at a rate of flow corresponding to the best efficiency.
Symbol: Hopt
Unit: m

 

Optimum pump power input

The pump power input at the rate of flow corresponding to the best efficiency.
Symbol: Popt
Unit: kW, W

 

Optimum rate of flow

Rate of flow at the point of best efficiency.
Symbol: Qopt
Unit: m3/s, m3/h, l/s, l/h

 

Outlet area of the pump

The free cross-sectional area of the orifice in the outlet connection of the pump.
Symbol: A2
Unit: m2

 

Outlet pressure of the pump

The pressure acting at the outlet area of the pump.
Symbol: pp2
Unit: bar, Pa

 

Outlet rate of flow

The rate of flow passing the outlet area of the pump from the outlet side of the installation.
Symbol: Q2
Unit: m3/s, m3/h, l/s, l/h

 

Overall efficiency

The proportion of the driver power input, Pmot delivered as pump power output, Pu.

ηgr = Pu / Pmot

Symbol: ηgr
Unit: -

 


P


Parallel operation

Pumps operating with inlet connections interconnected and outlet connections interconnected to permit simultaneous operation in the same system giving increased rate of flow.


Part

A piece of equipment which when assembled together with others makes a pump.


Peak point

The point of highest achieved total head in an unstable pump H-Q-curve.

 

Pressure at point x

The force per unit area exerted at the observed point x.
Symbol: px
Unit: bar, Pa

 

Pressure casing

A composite of all stationary pressure containing parts of the unit, including all connections and other attached parts but excluding the stationary and rotating / oscillating parts of shaft / rod seals.

 

Pressure head

The head corresponding to the pressure shown on a manometer at an observed point indicated by the subscript.
Symbol: H Mx
Unit: m

 

Pressure-temperature rating

Pressure-temperature limit of a component at given design and material.

 

Product lubrication

An arrangement in which the bearings are submerged in and lubricated by the pumped liquid.

 

Pump

In general pumps are defined as being terminated by their inlet and outlet connections as well as in general their shaft ends.

 

Pump (NPSHR) curve

The relationship between the net positive suction head required and the rate of flow at given operating conditions of speed and liquid.



Pump best efficiency

The greatest value of pump efficiency obtained at a given speed pumping a given liquid.
ηmax
Unit: -

 

Pump efficiency

The proportion of the pump power input, P, delivered as pump power output, Pu, at given operating conditions.

η = Pu / P

Symbol: η
Unit: -


Pump efficiency curve

The relationship between the pump efficiency and the rate of flow at given operating conditions of speed and liquid.


Pump mechanical power losses

The power absorbed by friction in bearings and shaft seal at given operating conditions of the pump.
Symbol: PJm
Unit: W, kW

 

Pump power input

The power transmitted to the pump by its drive.
Symbol: P
Unit: W, kW

 

Pump power input curve

The relationship between the pump power input and the rate of flow at given operating conditions of speed and liquid.



Pump power output

The useful mechanical power transferred to the liquid during its passage through the pump.
Symbol: Pu
Unit: W, kW


Pump rated power input

The power required by the pump at the rated conditions.
Symbol: Pr
Unit: W, kW


Pump unit

A pump unit comprises the pump, the drive including transmission elements, baseplate and any auxiliary equipment.


Pump-H-Q-curve = characteristic curve = pump head capacity curve

The relationship between the total head of the pump and the rate of flow at given operating / rated conditions of speed and liquid.


Pumped liquid

The liquid or fluid which will be handled by the pump at specified operating conditions.



Q

 

Quenching

Continuous or intermitted introduction of an appropriate (clean, compatible etc) fluid on the atmospheric side of the main shaft seal. Used to exclude air or moisture, to prevent or clean deposits (including ice), lubricate an auxiliary seal, snuff out fire, dilute, heat or cool leakage.

R

 

Radial split

Refers to casing joints that are transverse to the shaft centerline.

 

Rate of flow

The volume rate of flow corresponding to the mass rate of flow given by the equation: Q = q/ ρ.
Symbol: Q
Unit: m3/s, m3/h, l/s, l/h

 

Rated

A specified performance selected to ensure that the operating performance will be achieved by the pump or pump unit when installed.

 

Rated conditions

Conditions (drive excluded) that define the guarantee values necessary to meet all defined operating conditions, taking into account any necessary margins.

 

Rated differential pressure

The differential pressure for the operating conditions at the guarantee point.
Symbol: p1-2 r
Unit: bar, Pa

 

Rated flow

Rate of flow at the guarantee point taking into account any necessary margin.
Symbol: Qr
Unit: m3/s, m3/h, l/s, l/h

 

Rated inlet pressure

The inlet pressure of the operating conditions at the guarantee point.
Symbol: p1r
Unit: bar, Pa

 

Rated outlet pressure

The outlet pressure of the pump at the guarantee point with rated flow, rated speed, rated inlet pressure and density.
Symbol: p2r
Unit: bar, Pa

 

Rated speed

The number of rotation per unit of time of the pump required to meet the rated conditions.
Symbol: nr
Unit: min-1, s-1

 

Rotodynamic pump

A machine to transfer mechanical energy through a rotating impeller to gain velocity and pressure for the pumped liquid.

 

Rotor

The assembly of all rotating parts of a rotodynamic pump.



S

 

Seal flushing (circulation)

The return of pumped liquid from high pressure area to seal cavity. It can be by external piping or internal passage and is used to remove heat generated at the seal or to maintain positive pressure in the seal cavity or treated to improve the working environment for the seal. In some cases it may be desirable to circulate from the seal cavity to a lower pressure area.

 

Sealing liquid

Liquid introduced between pressurized double mechanical seals to completely isolate the pump process liquid from the environment.

 

Sealing liquid

Liquid used as a lubricant or buffer between unpressurized dual (tandem) mechanical seals.

 

Selfpriming pumps

Type E S SUB
Compared to non-selfpriming pumps, selfpriming pumps are in a position to evacuate the suction pipe line and consequently prime deep level liquids. Defective foot valves, gasing liquids or limited suction-side air admission will be controlled reliably. Short evacuation times and high efficiencies care for trouble-free operation and low life-cycle costs. Suitable for clean and slightly polluted liquids e.g. for water supply, dewatering, booster systems and irrigation.


Series operation

Pumps operating with the outlet connection of the first connected to the inlet connection of the next pump to permit simultaneous operation in the same system giving higher outlet pressure.


Shaft runout

The total radial deviation indicated by a device measuring shaft position in relation to the bearing housing as the shaft is rotated manually in its bearings with the shaft in the horizontal position.



Shaft stiffness

A comparative expression describing the ability of shafts to resist bending loads.

 

Shut-off head

The total head developed by the pump in a zero rate of flow.
Symbol: H0
Unit: m

 

Shut-off pump power input

The pump power input at zero rate of flow.
Symbol: P0
Unit: kW, W

 

Single flow

Impeller with single entry flow direction.

 

Single stage

A pump with one impeller only.

 

Solid content

The proportion of solids contained in the liquid to be pumped either as a contaminant or as a deliberate useful burden or suspension.
Symbol: -
Unit: % by wt.



Specific speed

The speed which characterises a pump in terms of its speed, flow rate per impeller eye, i.e. total flow for single flow impeller, one half flow for double flow impeller at best efficiency point and head per stage at maximum impeller diameter.
Symbol: ns
Unit: min-1

 

Speed

The number of rotations or movements made by the shaft, coupling or impeller in unit time.
Symbol: n
Unit: min-1, s-1

 

Stable pump H-Q-curve

A pump H-Q-curve where the maximum head and shut-off head are coincidental and the total head declines continuously with increasing rate of flow.

 

Stainless-Bloc pumps

Type CB BC
All-purpose circulation pumps in stainless steel for the use in the food industry, water supply, cooling and refrigeration technology, air-conditioning, filtration, shipbuilding, apparatus engineering, energy technique and general machine engineering. Wide ranges of applications for simple requirements and clean or slightly polluted liquids.

 

Standard DIN EN 733 pumps

Type N
Classic single-stage volute casing pumps on bed-plate in easy service process-design. For the transport of clean and slightly polluted liquids. Main applications water supply, water treatment, pumping stations and energy technique.

 

Standby pumps

Pumps additional to the duty need installed to provide immediate cover in the event of failure of the main pumps.

 

Static head

That portion of total head at an observed point in an installation which is independent of rate of flow.
Symbol: Hstat
Unit: m

 

Sub-assembly

An assembly of parts put together for convenience which may or may not fulfil a discrete function.

 

Submersible pump

A pump unit designed to operate fully submerged in the pumped liquid.

 

System

Those parts of an installation which together with the pump determine the functional performance of the installation.



T

 

Test

Terms which describe the characteristics of the pump or the fluid or the conditions which exist during an examination.

 

Throttle bush

Close-clearance restrictive bushing around the shaft (or sleeve) at the outboard end of a mechanical seal, to reduce leakage in case of seal failure.

 

Torque-Flow-Bloc pumps

Type FUB CBF
Torque-flow pumps in compact bloc-design for the transport of liquids being contaminated with solids or suspensions. Typical liquids to be pumped are waste water, cooling agents contaminated with metal chips, abrasive oils and lyes, lime milk and also products that have to be transported with care. Main application in sewage water plants, treatment systems, recycling processes, washing plants. filters, environmental and operation technique. All-purpose pump design insensitive to cavitation conditions.

 

Total differential head of the pump unit

The difference of the total head at the outlet side of the pump unit from the total head at the inlet side of the pump unit.
Symbol: Htgr1-2
Unit: m

 

Total head

The head at an observed point corresponding to the sum of the height, pressure head and the velocity head of the fluid at that observed point.
Symbol: Htx
Unit: m

 

Trip speed

The speed at which the independent emergency overspeed devices operate to shut down a prime mover.
Symbol: ntrip
Unit: min-1, s-1



U

 

Unstable pump H-Q-curve

A pump H-Q-curve where the maximum head (peak point) and shut off head are not coincidental or the total head does not decline continuously with increasing rate of flow.

V

 

Vapour pressure of the pumped fluid

The absolute pressure at which the liquid vaporizes corresponding to the temperature of the liquid.
Symbol: pv
Unit: bar, Pa

 

Velocity head

The head corresponding to the kinetic energy in the fluid at the observed point indicated by the subscript.
Unit: m

W

 

Working

Conditions existing at the moment that an event is noted or a quantity is measured.



X

Y

Z



Source: In extracts the terms correspond to the DIN EN 12723.



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