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Saturation pressure

Saturation pressure is the pressure at which an equilibrium is established between the individual ...

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Scale-up

Scaling up describes the efficiency improvement of two geometrically similar centrifugal pumps (e. g.

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Screw pump

A screw pump is a rotary positive displacement pump with two intermeshing counter-rotating screws ...

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Sealing element

Sealing elements, or seals, are components or constructions which help to limit or prevent the ...

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Seawater

From a chemical perspective, seawater is a saline, aqueous solution. The salinity of individual seas ...

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Seawater desalination system

Seawater desalination plant: Multi-stage flash (MSF)

A seawater desalination system is a facility for producing drinking water or service water from seawater.

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Seawater pump

Seawater pumps are centrifugal pumps for seawater used for cooling purposes (see Marine pump) made of ...

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Selection chart

A selection chart is a graphic representation of the characteristic curves selection charts of ...

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Self-priming pump

Self-priming pump: Self-priming pump with separation chamber (without self-priming stage)

In normal conditions, common centrifugal pumps are unable to evacuate the air from an inlet line ...

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Self-regulation

Self-regulation is a type of closed-loop control whereby the H/Q curve is changed by self-regulating ...

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Sensor

A sensor is also referred to as a transmitter or pick-up and qualitatively or quantitatively (as ...

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Series operation

Series operation means that pumps are connected and started one after another, i. e. in series. This ...

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Series-produced pump

Series-produced pumps are pumps that are manufactured in series rather than undergoing customised ...

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Service water

Service water designates water used for purposes other than drinking. It is intended for specific ...

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Service water pump

A service water pump is a pump employed to handle service water used in industrial processes. It is ...

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Sewage lifting unit

Fäkalienhebeanlage: Fäkalienpumpe als Blockpumpe in einer Fäkalienhebeanlage

Single-pump or dual-pump sewage lifting units are used in buildings, including hotels and hospitals, ...

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Sewage pump

Sewage pumps transport sewage and untreated waste water (e. g. raw waste water). They are most ...

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Shaft coupling

The shaft coupling is the connecting element between the electric motor and the pump hydraulic system.

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Shaft efficiency

Shaft efficiency is also known as pump efficiency.

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Shaft protecting sleeve

The shaft protecting sleeve is fitted to the shaft and rotates in the bearing bush. It protects the ...

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Shaft seal

Shaft seal: Lip seal

The shaft seal is a sealing element which seals the rotating shaft of a centrifugal pump where it ...

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Shaft seal ring

The shaft seal ring, often also called radial shaft seal ring or lip seal, is a contact-type shaft seal.

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Shear stress

Shear stress (τ) on fluid particles of a fluid of normal viscosity (see Viscosity) and on walls in ...

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Shielded cable

A shielded cable comprises a conductor that is enclosed by at least one cable shield (conductive sleeve).

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Shielding

Shielding refers to the protection of a conductor from external electromagnetic influences (also see ...

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Shock-free entry

In a vane cascade, shock-free entry is given if the relative flow (see Relative velocity) of the ...

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Shock loss

If the angle of attack of a vane cascade differs from the inlet angle of the vanes (see Shock-free ...

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Shut-off element

Shut-off elements are pipe components which coordinate flow. This can mean controlling flow volume ...

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Shut-off head

The shut-off head of a pump indicates the amount of pressure required to reach a condition where the ...

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SI

The term SI is the abbreviation for "Système international d’unités", which is the international ...

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Side channel pump

Side channel pumps share the characteristics of both positive displacement pumps and centrifugal pumps.

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Similarity conditions

The similarity theory requires that three essential conditions be met for hydraulic model tests:

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Single-phase alternating current

Single-phase alternating current is alternating current, that flows through a two-core cable and is ...

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Single-phase asynchronous motor

The single-phase asynchronous motor is an electric motor that is operated using single-phase current.

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Single-vane impeller

Single-vane impellers (See Figs. 7, 8, 16 Impeller) can be classified in radial, open diagonal and ...

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Siphoning line

Siphoning lines are used to safely draw liquids from storage tanks from the top. In addition, they ...

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Slave

The slave is a participant in a communications system that can only participate in the exchange of ...

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Slip

Slip plays an important role in calculating the radial or mixed flow impeller of a centrifugal pump ...

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Slip ring rotor

The slip ring rotor characterises an asynchronous motor whose rotor has a slip ring design. Unlike ...

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Sludge pump

The sludge pump is a type of pulp pump.

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Slurry pump

Slurry pump: With replaceable suction-side wear plate

A slurry pump is also known as a lined pump or dredge pump and is a centrifugal pump for transporting ...

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Smooth running

The term smooth running of centrifugal pumps as viewed from a technical perspective refers to the ...

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Soft starter

The soft starter is an electronic solution for gradually accelerating and decelerating or braking ...

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Soft starting

The soft starting process encompasses all measures (e. g. use of a soft starter) that enable gradual ...

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Soft start throttle

The soft start throttle is an economical and robust control gear of simple design for squirrel-cage ...

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Solar pump

Solar pumps are normally used for handling water in sunny regions without a mains supply. The power ...

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Solids transport

Fluids can be used for the transportation of fine- and coarse-grained solids. This process requires ...

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Sound insulation

Sound insulation is a passive form of noise abatement whereby the pump and drive are enclosed in ...

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Sound level

The term sound level can refer to loudness as it is perceived by humans or to the sound pressure ...

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Sound pressure level

The sound pressure level is a measure for describing the intensity of sound. Its unit is the db ...

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Specific energy

The specific energy (Y) is the useful mechanical energy transmitted by the centrifugal pump to the ...

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Specific speed

The specific speed (ns) is a characteristic coefficient derived from the similarity conditions which ...

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Speed control

Speed control: Pole change

The controlled adjustment of rotational speed as it applies to rotating machines and, thus, ...

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Speed measurement

Speed measurements are used to quantify the speed at which a body rotates and can be carried out in ...

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Speed transmitter

Speed transmitters are also referred to as rotary pulse encoders or incremental transmitters and ...

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Sprinkler pump

The sprinkler pump is used for supplying fire-fighting water and an example of a stationary ...

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Squirrel-cage motor

The squirrel-cage motor is an asynchronous motor with rotors whose geometry resembles a squirrel cage.

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Stable H/Q curve

A centrifugal pump's H/Q curve is called stable if it exhibits a continuously negative slope ...

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Stage

Each stage of a multistage centrifugal pump consists of a combination of an impeller with a diffuser ...

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Standardised chemical pump

Standardised chemical pump: Pump to EN 22858 / ISO 2858 / ISO 5199

Standardised chemical pumps are chemical pumps with standardised dimensions and hydraulic output (see ...

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Standardised pump

Standardised pumps are pumps which comply with the requirements, guidelines, directives or ...

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Standardised water pump

A standardised water pump is a standardised pump, which differs by comparison with the standardised ...

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Standard nozzle

Standard nozzle: General design

The standard nozzle is a differential pressure measuring instrument whose geometric dimensions, ...

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Standard orifice

The standard orifice is also referred to as a measuring orifice or simply an orifice and is a ...

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Standard pressure

Standard pressure is a globally defined and standardised condition (STP for "Standard Temperature and ...

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Standard signal

The standard signal is a standardised electrical or pneumatic signal used in process automation. For ...

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Standard temperature and pressure

According to DIN 1343 standard temperature and pressure is a specific state for a solid, liquid or ...

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Standard Venturi nozzle

The standard Venturi nozzle is a differential pressure measuring instrument whose geometric ...

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Star configuration

In a star configuration all three phase conductors of a three-phase system are electrically connected ...

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Star-delta starting

Star-delta starting is also referred to as Y-delta or wye-delta starting and describes a starting ...

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Star impeller

The star impeller is a component installed in side channel and liquid ring pumps such as the water ...

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Starting method

The squirrel-cage motors used for centrifugal pumps (see Asynchronous motor) have high starting currents.

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Starting torque

Starting torque is the torque transferred by the shaft coupling during run-up (see Start-up process).

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Start-up

The starting of pumps is referred to as the start-up process.

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Start-up process

The start-up process refers the process by which the drive is activated and accelerated until the ...

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Static pressure

Static pressure refers to the pressure that would be measured by a sensor moving along with the fluid.

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Stator

The stator as used in electric motors is a stationary, non-moving part of an electrical machine. It ...

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Steady flow

The flow of a fluid is steady if its velocity, pressure and all the numerical values relating to its ...

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Stop pressure

The stop pressure indicates when a pump has to be switched off because it has exceeded the required ...

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Straight length of piping

The term "straight length of piping" is primarily used in metrology, i.e. when measuring flow rates ...

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Straight-way valve

Straight-way valves are distinguished from other globe valve types by their geometry, i.e. their ...

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Strain gauging

Strain gauging in the context of centrifugal pumps is used primarily to determine the strength of ...

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Stream line

In a flow, the stream line is a line whose local direction corresponds to the direction of the local ...

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Stress corrosion cracking

Stress corrosion cracking is a type of corrosion that causes cracks with intercrystalline (along the ...

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Stripping system

A stripping system is an auxiliary device on cargo oil pumps which enables the continuous discharging ...

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Strouhal number

The Strouhal number is defined as follows: w     velocity of flow around a body (for propellers, ...

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Submersible borehole pump

Submersible borehole pump: Combined with water-filled wet motor to form a submersible borehole pump set

Submersible borehole pumps are a type of submersible pump. They are centrifugal pumps driven by a ...

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Submersible borehole pump for use in tank farms

Submersible borehole pumps for use in tank farms are submersible borehole pumps which are used for ...

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Submersible mixer

Submersible mixer: Propeller in horizontal position

A submersible mixer is a mixing unit consisting of an open axial propeller and a dry submersible ...

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Submersible motor

A submersible motor is an asynchronous squirrel-cage motor wetted on the outside and inside, i. e. it ...

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Submersible motor pump

Submersible motor pumps are pumps driven by an asynchronous motor. Their hydraulic components (pump ...

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Submersible pump

Submersible pumps are centrifugal pumps whose hydraulic components (pump casing, impeller, diffuser ...

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Submersible pump in discharge tube

Submersible pump in discharge tube: Submersible motor pump in concrete discharge tube

A submersible pump in discharge tube consists of a centrifugal pump and a submersible motor. The ...

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Suction casing

The suction casing on ring-section pumps with radially split casings is a portion of the pump casing ...

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Suction characteristics

A centrifugal pump's suction characteristics describe the pump's reaction to changing NPSHa values ...

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Suction coefficient

The suction coefficient (S) introduced by Pfleiderer – but no longer used – is a characteristic ...

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Suction elbow

The suction elbow is also referred to as intake elbow.

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Suction eye

The term suction eye designates the inlet cross-section of an impeller.

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Suction head

The suction head is the geodetic height of a liquid level above the impeller inlet. See Fig. 1 NPSH ...

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Suction intake chamber

The suction intake chamber is an intake chamber from which the fluid handled is removed by ...

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Suction lift

Suction lift is the short form for geodetic suction lift.

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Suction line

The suction line is the section of piping in a pump system which extends from the extraction point (e. g.

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Suction nozzle

Suction nozzle is the short form for pump suction nozzle.

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Suction specific speed

Suction specific speed nss as defined in EN 12723 is used to classify the suction characteristics of ...

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Suction stage impeller

The suction stage impeller is the impeller of the first stage (suction stage) of a multistage pump.

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Suction strainer

The suction strainer is a valve which is installed at the suction line's inlet to prevent the ...

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Sudden collapse of vapour-filled cavities

This phenomenon can be understood as the sudden and violent collapse of vapour space in the event of ...

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Super-pressure pump

The super-pressure pump is a centrifugal pump with a head in excess of 1200 m, which is used, for ...

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Surface protection

Despite the development of advanced materials which provide high levels of wear resistance and ...

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Surge arrester

The surge arrester is a component such as the zener and suppressor diode or the varistor and limits ...

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Surge pressure

Surge pressures, or pressure surges, occur in a pipe transporting fluid as a result of a change in ...

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Swimming pool pump

Swimming pool pumps are circulating pumps for circuits used in swimming pool filter systems, for example.

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Swing check valve

The swing check valve is a valve which prevents reverse flow through the pump. Check valves are the ...

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Swirl

The term "swirl" is generally used as a synonym for the angular or rotational momentum of a rotating ...

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Swirl control

According to Euler's equation for turbomachinery, both the increase in energy in a centrifugal pump's ...

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Switchgear and controlgear

Switchgear and controlgear as defined by IEC 60947 for electronics applications encompass all ...

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Synchronous motor

The synchronous motor is a three-phase motor whose magnetic field is generated in the rotor via an ...

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Synchronous speed

Synchronous speed is the speed of a synchronous machine (e. g. three-phase generator) and is defined ...

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System characteristic curve

The system characteristic curve (see Characteristic curve) represents the relationship between the ...

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System curve

The system curve is also referred to as the system characteristic curve.

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