The terms we use in our technical data

Terminology used in pump industry

Below we give an explanation of the terms we use within the descriptions and data sheets

“Manual or Auto” + on level and off level…pump operation

 "M” or “manual”: a float switch is not fitted. The pump will require an operator to control the water level by switching the pump on or off at the mains, because it will operate immediately when power is applied. Some pumps must not be run dry, so care should be taken not to operate them without water, unless we have stated that it is possible to do so.

 “A” or “auto”: a float switch is fitted. The pump will turn itself on and off automatically with a rise and fall of the water level, so the presence of an operator is not required. When power is connected, the pump will only operate when the float switch is actuated, which generally occurs at or about the point when the top of the pump casing is submerged. The float normally stops the pump when the water level is still covering the impeller, so it is normal for residual water to remain in the sump. The volume of this water can be minimised by fitting a non-return valve in the discharge pipe near the pump, to prevent back flow into the sump.  It is vital to ensure that no protrusions, pipes, wiring, debris etc. can obstruct the float switch movement.  Failure of the float to move freely could damage the pump due to dry running, and/or cause flooding. Pendant float switches can only be adjusted slightly, and should not be altered so much that the pump will not start or stop. If you do adjust it, check the pump operates correctly before relying on the installation i.e. feed water into the chamber/sump slowly. Watch it starting and stopping and adjust if necessary. Turning the float up and down by hand is not sufficient. 

When selecting an automatic pump for an application, it is essential that the dimensions and volume of the sump allow full and free movement of the float. Too small a sump can lead to rapid on/off operating cycles, whereas a larger sump will reduce the number of starts the pump will make and, in turn, increase its life. Most motor manufacturers suggest no more than 25 starts per hour. Many outside influences can alter the point at which an automatic pump starts or stops operating. An example of this would be a build up of grease or fat on the pump, the float, or the walls of the chamber. Therefore we strongly recommend that all installations are inspected regularly to check operation.

“outlet (mm)”…pump connections

When the figure is given in an imperial measurement (e.g. 1¼”) then the inlet and/or outlet is threaded. A hose tail would be necessary if fitting to a flexible pipe is required.

When the figure is given in a metric measurement (e.g. 32mm) then the inlet and/or outlet is supplied with a hose tail to enable fitting to a flexible pipe.

 “outlet” (where you find outlet on a page): this is the internal diameter size of the discharge pipe required to suit the pump outlet port. Outlet pipe sizes can be reduced, e.g. to match existing pipe-work, however, due to increased friction losses, pumping capacity will be reduced, and power consumption may be affected. On solids handling pumps particularly, the risk of blockage is also increased. Outlet pipe size can be increased to improve flow over long pipe runs, but must not be of such a diameter that the pump is caused to operate below its minimum head. Please consult our Sales Department for advice if you wish to operate a pump with a discharge pipe diameter different to that published.

“inlet” (where you find inlet on a page): this is the internal diameter size of the inlet pipe required to suit the pump inlet. Reducing this size is not recommended as cavitation or erratic operation of the pump could result, leading to greatly reduced pump life. In some instances, e.g. suction lift duty on oils, it may actually be necessary to increase the bore of the suction pipe from that specified. Inlet pipe or suction hose must have a sufficiently rigid construction and temperature range to avoid collapsing during pump operation.

 

Submersible sewage pumps models are supplied in two versions:

 “free-standing version”: this includes feet or a support stand, and a mating flanged elbow with a female BSP outlet flange to suit a hose tail or pipework.

“fixed-guide rail version”: this includes the components required for guide rail mounting, but excludes the guide rails.

“kW” and “watt”MOTORS

 our published motor power ratings are “output” powers, but the power drawn from the mains (“input”) will always exceed this figure. As a guide, the percentage difference between output and input is greater on the lowest powered motors. An input figure should be used for calculating running costs and will vary depending on the application.

 Voltage: the voltage that this model is available. When you see two voltages on one line e.g. 110•230 this means the pump is available in one or the other voltage, but not dual voltage.

“amp”(page 48, 49, 86, 87 & 90): this is the full load current specified on the motor rating plate, i.e. the running current. Instantaneous starting currents will be several times this figure and details can be supplied if needed for any application, e.g. when running off a generator.

Current: our single and three phase pumps run on A.C. (alternating current) while low voltage pumps run on D.C. (direct current)

Frequency: all our AC motors are designed for 50Hz operation, but some models have alternative frequencies available.

motors on pumps IP

Motor enclosure ratings: motors are classified according to the degree of enclosure protection. The designation used for the degree of protection consists of the letters “IP” followed by two characteristic numerals.

The first characteristic numeral (0 – 6) designates the degree of protection of persons against contact with live or moving parts inside the enclosure and protection of machines against ingress of solid foreign bodies.

The second numeral (0 – 8) designates the degrees of protection of machines against harmful ingress of liquids.

Explosion proof motors: ATEX

Many industrial processes utilising flammable materials have the potential to give rise to a potentially explosive atmospheres. Potentially explosive atmospheres exist where there is a risk of explosion due to mixtures of gas and air, vapour and air, dust and air or other flammable combinations. Where a potentially explosive atmosphere is present, in order to protect personnel and plant, measures must be taken to ensure that the electrical equipment cannot ignite that potentially explosive environment. It is therefore necessary to eliminate all sources of ignition which might ignite such mixtures. These sources include, for example, electrical arcs and sparks, flames and hot surfaces, static electricity and mechanical impact and friction. To ensure compliance, equipment, such as pumps, must meet the essential requirements as specified in the ATEX Directive 94/9/EC and be marked with the CE marking for EU use. Information on this website that describes the explosion proof pumps, carry a classification e.g. Eexd-ІІB-T3- ІІ-2-G. The key is as follows (and this pump’s classification):

Eexd –   type of protection (explosion proof enclosure)
ІІB – gas group (ethylene)
T3 – maximum surface temperature (200° C)
ІІ – group (surface)
2 – level of protection for zone (high level of protection for zone 1)
G – type of hazardous atmospheres (gases, vapours, mists)
 
“duty”: 
Pumps: most of our A.C. pumps, have continuously rated motors. If you intend to run a pump continuously, please check with our Sales Department to check its suitability.  Motors on some of our D.C. pumps are shown as continuously rated, while others have an intermittent rating that requires a period of rest, after running, for cooling purposes. 

N.B. – Even if continuously rated, all our D.C. motors have a finite brush life. 

Panels: the number of pumps that can be operated from the panel and at what voltage.

Pumping Performance

“flow” (flow l/min): published flows are given in litres per minute and are based on pumping clean, cold water (or diesel, or oil, when referring to fuel and lubricant pumps), through the outlet bore specified. This figure is the maximum the pump can deliver at the minimum head recommended. Flow will decrease with an increase in head created by adding pipe vertically (physical head), and/or horizontally (head due to friction losses in pipe run)

“head” (head mtrs): published heads are given in metres and are based on pumping clean, cold water (or diesel, or oil, when referring to fuel and lubricant pumps), through the outlet bore specified. The figure is the maximum height of a vertical column of water that the pump could support if there were no other losses in the system. For submersibles, head is the distance from the water level to the highest point in the pipeline.  For surface mounted pumps operating with a flooded suction, it is the distance from the pump’s centre line to the highest point in the pipeline.  For surface pumps operating with a suction lift, the total head is again the distance from the water level to the highest point in the pipeline. In practice total head is not simply a height difference between suction and delivery points, because the friction losses created by horizontal pipe-work, valves, elbows, etc., and the specific gravity and viscosity of the liquid need to be added. This means that, in systems with long pipe runs and many fittings, pump output may be greatly reduced. 

“suction lift”: published lifts are given in metres and are based on pumping clean, cold water(or diesel, or oil, when referring to fuel and lubricant pumps), through the inlet bore specified. A “suction lift” is the distance from the pump’s centre line to the water level. There are few limitations on the discharge side of a pump or pumping system, however there are very definite limitations to the suction side. This is why we suggest that submersible pumps should always be chosen in preference to surface mounted pumps, whenever possible. The theoretical maximum lift for clean, cold water is approximately 10 metres; however in practical terms it is considerably lower and we recommend 6 metres or less of inlet pipe. For fuel transfer pumps the maximum is even lower and 3 metres or less is recommended. For oil transfer pumps it is 2 metres or less. In all cases the additional the losses created by horizontal pipe-work, valves, elbows, specific gravity and viscosity of the liquid need to be added.

Performance Curves: these indicate the output possible at measured points. Care should be taken not to select a pump for operation off the bottom or the top of the curve, as this could lead to premature pump failure. Ideally the pump should operate within the middle third of the curve to achieve maximum efficiency. Published flows are given in litres per minute at a head point in metres, and are based on pumping clean, cold water(or diesel, or oil, when referring to fuel and lubricant pumps), through the outlet bore specified. From the preceding notes it should be obvious that all aspects of the system must be taken into account when making a pump selection. Please consult our Sales Department for advice and guidance when using these curves.  

Dimensions & Weights

"w x l x h” (width x length x height) or “diam x h”(diameter x height): the figures published are either taken from the manufacturers’ latest specifications or, when these are not available, from our own measurements. If your application requires precise information we strongly recommend that you request written confirmation from our Sales Department. 

Submersible pumps: the width dimension excludes the hose coupling (when supplied). The height is measured to the top of the handle, lifting-eye or outlet, which ever is greater. 

Surface pumps: the height and length, in most cases, excludes the handle, hose couplings and any hose kit.

Engine pumps: for centrifugal pumps this is the outside dimension of the frame or base plate (WX10). For the diaphragm pumps, the dimensions include the chassis, wheels, prop stands and handles.

Hand pumps: dimensions exclude the length of the removable lever on the DD and SD45 pumps. It is inclusive of the integral lever on the SD60. Where a foot-plate is fitted, the dimensions include this size. For the rotary pumps, the outlet and riser pipes dimensions are included. Hoses and hose kits are not included in any dimension.

dry weight: is the weight of the pump only so excludes any power cable, hoses or connections. For Tsurumi free-standing sewage pumps, it includes the flanged elbow. 

packing weight: is the weight of the product in the packaging, for the purposes of delivery

 NB: figures published are approximate and either taken from the manufacture’s latest specifications or, when these are not available, from our own measured weight. This data should be used as a guide only and, if your application requires specific information, then we strongly recommend that you ask our Sales Department to provide written confirmation. 

Solids Handling

free passage mm”: this is the size of the solids that the manufacturer specifies that the pump can pass.

Engines

Petrol driven pumps run on unleaded fuel.

“oil alert”: this is a protection device for petrol engines that will stop the engine during operation or prevent the engine starting, if there is insufficient oil in the sump.

Diesel engine pumps run on red or white diesel, but not bio-diesel.

PLEASE NOTE

Data on our website has been gathered from our manufacturers’ most recent published specifications and, when this has not been available, from our own research. While we make every effort to ensure that the information is accurate, mistakes can occur and we cannot be held responsible for consequential loss suffered as a result of errors, omissions or approximations. We are also constantly improving and updating our products and, as a result, reserve the right to alter specifications without notice. This data should be used as a guide only and, if your application requires more specific information, then we strongly recommend that you contact our sales Department to provide written confirmation.