Table of Acronyms & Definitions
Acronyms and defintions for centrifugal, mixed flow, axial flow, rotary and reciprocating pumps, and pump system terms that are used within the HI Data Tool are included. The industry source is prvided for the definition and a link is provided to the HI Data Tool section the term is used or discussed.
Index
Acronyms
| Term | Description |
|---|---|
| AOR | Allowable operating region |
| BEP | Best efficiency point |
| NPSH3 | Net positive suction head required resulting in 3% loss of total head |
| NPSHA | Net positive suction head available |
| NPSHR | Net positive suction head required |
| POR | Preferred operating region |
| VFD | Variable frequency drive |
| VSD | Variable speed drive |
Definitions
| Term | Description | HI Source | Section |
|---|---|---|---|
| Abrasive wear (or abrasion) | Wear due to hard particles or hard, small surface protrusions forced against and moving along a material surface. Wear occurring by the mechanical action of suspended abrasives or by abrasives that crystallize on the atmospheric side of the seal. | ANSI/HI 14.1-14.2 | Solids and Slurries |
| Affinity rules | Describe the relationship of the pump performance curve relative to pump rotational speed changes and limited changes in impeller diameter. | ANSI/HI 14.3 | Pump Curves |
| Allowable operating region (AOR) | A wider range of rates of flow, inclusive of the POR, over which the service life of a pump, although reduced, is within acceptable limits. | ANSI/HI 9.6.3 | Pump Curves |
| Best efficiency point (BEP) | The best efficiency point (BEP) is the rate of flow and head at which the pump efficiency is a maximum at rated rpm or at a given speed and impeller diameter. | ANSI/HI 14.1-14.2 | Pump Curves |
| Cavitation | Cavitation is the process of vapor cavity formation in a flowing liquid, in a region where the pressure falls below the liquid’s vapor pressure, followed by rapid collapse of cavities due to an increase in pressure downstream. | ANSI/HI 3.1-3.5 | Pump Principles |
| Concentration of solids by mass (or weight) | The mass (or weight) of dry solids in a given volume of slurry, divided by the total mass (or weight) of that volume of slurry, multiplied by 100 and expressed in percent. | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Concentration of solids by volume | The actual volume of the solid material in a given volume of slurry, divided by the given volume of slurry, multiplied by 100, and expressed in percent. | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Corrosion | Loss of material created by chemical or electrochemical reaction within the pump environment | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Francis-vane impeller | In impellers of this type, the liquid enters the eye of the impeller axially and exits semi-radially, at about a 60° to 70° angle to the shaft axis. | ANSI/HI 14.1-14.2 | Pump Principles |
| Friction head | Friction head is the hydraulic energy required to overcome frictional resistance of a piping system to liquid flow expressed in meters (feet) of liquid. | ANSI/HI 14.1-14.2 | System Curves |
| Impeller, axial flow | An axial-flow impeller has a single inlet with the flow entering and discharging axially (or nearly axially). | ANSI/HI 14.1-14.2 | Pump Principles |
| Impeller, Barske | This impeller design represents the lowest range of specific speed for rotodynamic pumps and consists of straight, radial vanes with open or semi open construction. | ANSI/HI 14.3 | Pump Principles |
| Impeller, enclosed | An enclosed impeller has both a inlet and hub shroud with leakage controlled by internal running clearances. | ANSI/HI 14.1-14.2 | Pump Principles |
| Impeller, mixed flow | The mixed-flow impeller has a single inlet with the flow entering axially and discharging about 45° with shaft axis, to the periphery. | ANSI/HI 14.1-14.2 | Pump Principles |
| Impeller, open | An impeller with no front shroud and no (or a minimum) back shroud with the vanes running in close proximity to mating casing walls, side plates, or liners. | ANSI/HI 14.1-14.2 | Pump Principles |
| Impeller, radial flow | In radial flow (vaned) impellers the liquid enters the eye of the impeller axially and is turned by the impeller vanes and shroud to exit perpendicular to the axis of the pump shaft | ANSI/HI 14.1-14.2 | Pump Principles |
| Impeller, semi-open | An impeller with a shroud only on one side, leaving the vanes exposed on the other side. | ANSI/HI 14.1-14.2 | Pump Principles |
| K value (valves and fittings) | Head loss though valves and standard fittings (minor losses) can be expressed in terms of a resistance coefficient K and the velocity head. The value of K can be found for various fittings in the referenced sources and the Losses in Valves, Fittings and Bends section of the EDL. | Combined Pump & System Curves | |
| Major losses (pipe friction) | The friction head loss associated with fluid moving through straight pipe. Refer to Friction Loss Calculator (https://datatool.pumps.org/tools/frictional-losses.html) | Pipe Frictional Losses | |
| Minor losses (valves & fittings) | The friction head loss associated with fluid moving through anything that is not straight pipe (valves, fittings, bends, nozzles, tank entrance and exits, etc.). Also see K value. | Losses in Valves, Fittings, and Bends | |
| Net positive suction head 3% (NPSH3) | The value of NPSHR at which the first-stage to head drops by 3% due to cavitation. | ANSI/HI 14.1-14.2 | Pump Principles |
| Net positive suction head available (NPSHA) | (14.1-14.2) The total suction head of liquid absolute, determined at the NPSH datum, less the absolute vapor pressure head of the liquid.
(6.1-6.5) For a reciprocating pump, acceleration head loss is subtracted from the total suction head of the liquid absolute. | ANSI/HI 14.1-14.2, HI 6.1-6.5 | Pump Curves |
| Net positive suction head required (NPSHR) | NPSHR is a minimum NPSH given by the manufacturer/supplier for a pump achieving a specified performance at the specified rate of flow, speed, and pumped liquid. | ANSI/HI 14.1-14.2 | Pump Curves |
| Parallel operation | Parallel pumping is when two separate pumps operate at the same time using the same inlet and discharge piping. | ANSI/HI 14.3 | Pump Curves |
| Preferred operating region (POR) | The preferred operating region (POR) is a range of rates of flow to either side of predicted BEP within which the hydraulic efficiency and the operational reliability of the pump are not substantially degraded. | ANSI/HI 9.6.3 | Pump Curves |
| Pump efficiency (ηP) | The ratio of the pump output power to the pump input power; that is, the ratio of the liquid horsepower to the brake horsepower expressed in percent. Efficiency is expressed in percent. This term is used interchangeably with hydraulic efficiency. Also called pump mechanical efficiency | ANSI/HI 14.1-14.2 | Pump Curves |
| Pump input power (PP) | The power needed to drive the complete pump assembly, including bowl assembly input power, line-shaft power loss, mechanical seal or gland packing friction losses, and thrust bearing loss. It is also called brake horsepower. | ANSI/HI 14.1-14.2 | Pump Curves |
| Pump performance curve | A pump performance curve is a graphical representation of the head generated, power, efficiency, and NPSHR by a specific pump model at rates of flow from zero to maximum at a given operating speed. | ANSI/HI 14.3 | Pump Curves |
| Pump rate of flow (Q) | The rate of flow of a pump is the total volume throughput per unit of time at suction conditions. It includes both liquid and any dissolved or entrained gases at the stated operating conditions. Rate of flow is expressed in cubic meters per hour (gallons per minute). | ANSI/HI 14.1-14.2 | Pump Curves |
| Pump runout (maximum flow) | The highest flow rate shown on the published pump curve. | Pump Curves | |
| Series operation | Series pumping, sometimes referred to as staging, is when the discharge of one pump is routed into the inlet of the next pump. | ANSI/HI 14.3 | Pump Curves |
| Shut-off head | The pump head at the condition of zero flow where no liquid is flowing through the pump, but the pump is primed and running. | ANSI/HI 14.1-14.2 | Pump Curves |
| Slurry | Slurry is a mixture of solids (specific gravity typically greater than 1) in a liquid carrier, usually water. | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Specific gravity of liquid | Specific Gravity is the ratio of density of a liquid relative to the density of water. The reference density for liquid used in Hydraulic Institute standards is based on water at 20 °C (68 °F) which is 998.2 kg/m³ (62.31 lbm/ft³) | ANSI/HI 14.1-14.2 | Solids and Slurries |
| Specific gravity of slurry (or mixture) | The relative density of the slurry (mixture) to that of water at the same temperature. | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Specific gravity of solids | The relative density of solids with respect to water at standard temperature of 4 °C (39.2 °F). | ANSI/HI 12.1-12.6 | Solids and Slurries |
| Specific speed (ns, Ns) | An index of pump performance at the pump's best efficiency point (BEP) rate of flow, with the maximum diameter impeller, and at a given rotational speed. | ANSI/HI 14.1-14.2 | Pump Principles |
| Submergence | The vertical distance from the free surface of the liquid pumped to the center point of entry at the pump inlet, suction piping, or formed suction intake. | ANSI/HI 9.8 | Submergence |
| Suction specific speed (S, Nss) | Suction specific speed is an index of pump suction operating characteristics determined at the BEP rate of flow with the maximum diameter impeller. | ANSI/HI 14.1-14.2 | Pump Principles |
| System curve | A system curve is a representation describing the head requirement of the system as a function of flow rate | System Curves | |
| System static head | The height a liquid must be lifted as measured from the free surface of the liquid supplying the pump to the free surface of the liquid's destination, plus the difference in pressure acting upon these surfaces, expressed in height of the liquid. | System Curves | |
| Total head (H) | This is the measure of energy (work) increase per unit weight of the liquid, imparted to the liquid by the pump, and is the difference between the total discharge head and the total suction head. | ANSI/HI 14.1-14.2 | Pump Principles |
| Type number (K) | A variation of impeller specific speed. Type number is a dimensionless quantity calculated at the point of best efficiency. | ANSI/HI 14.6 | Pump Principles |
| Variable frequency drive (VFD) | An electronic device used primarily for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. | HI Application Guideline for Variable Speed Pumping | Pump Curves |
| Variable speed drive (VSD) | Any device that can be used to vary the speed of the pump, either mechanically or electronically. This may include (but is not limited to) eddy current drives, magnetic drives, variable frequency drives, a hydraulic clutch, fluid drives, variable V-belt drives, and various variable mechanical drives, steam turbines, and gas turbines. | HI Application Guideline for Variable Speed Pumping | Pump Curves |
| Velocity head | Velocity head is the kinetic energy per unit mass of the liquid in movement divided by g at a given section. | ANSI/HI 14.1-14.2 | System Curves |
| Viscosity (absolute viscosity, dynamic viscosity) | A measure of a liquid's tendency to resist an internal shearing force. For the same given internal shear rate, a liquid that requires a high shear stress has a high viscosity and a liquid that requires a low shear stress has a low viscosity. | ANSI/HI 10.1-10.5 | Viscosity |
Last updated on April 19th, 2024