FAQ Spandau Pumpen
Here you can find answers of questions about Spandau Pumpen
- How they work
- Design features
- Electrical parameters
If you have any more questions, please contact us via our contact form.
The drive motors conform to VDE regulations as well as European motor standards (DIN EN 60 034-1) and bear a CE mark.
Versions compliant with non-European regulations, e.g. CSA, UL or other country-specific requirements are possible.
When frequency converters are used make sure that RC elements provide for interference suppression and, as the case may be, for voltage smoothing.
In principle, thermistor-type motor protection can only be achieved with the use of thermal sensors (PTC) with a corresponding tripping unit.
Unless otherwise indicated, the characteristic curves shown in the brochures apply to viscosities of 1 mm²/s at a density of 1kg/dm³.
But selected types of pumps also permit higher viscosities. You can find more precise information in our brochures. The maximum viscosities amount to the following in the case of:
- centrifugal pumps: 20 mm²/s
- positive-displacement pumps: 2,500 mm²/s
Higher viscosities are available on request.
Due to the design of individual pumps it is possible to permit varying degrees of contaminants in the liquid being pumped. So it is possible to pump clean, turbid and dirty liquids.
The following applies to centrifugal pumps: contaminant grain sizes of 0.3 mm to 8 mm are permissible, depending on the type of pump. In this respect the lower values apply to closed impellers and the higher values to open ones.
Another factor is the quantity of the contaminants found in the liquid. Here, too, the following applies: large quantities of contaminants require the use of open impellers.
The following applies to screw pumps: due to the way they work, only clean liquids without abrasive or long-fibered constituents (contaminated with a maximum grain size of 0.05 mm at a maximum of 40 mg/l) are permitted in the case of screw pumps.
For more information please contact us.
For every type of pump there are restrictions on the temperature of the pumped liquids due to the materials used. You can find concrete information on this in the respective brochures.
Among the plastic pumps there are ones that are limited to temperatures of -30 °C to +60 °C. This range is expanded to limits of -100 °C to +150 °C by the use of a special plastic.
Limits of -30 °C to +90 °C generally apply in the case of pumps made of metal. With special version it is possible to extend this range to -70 °C to +170 °C.
Spandau Pumpen are used for a large number of industrial liquids.
They include, among others, emulsions, cooling brines, lacquers, lyes, inks that contain solvents, oils, organic solutions, cleansers, acids, lubricants, thermal oils, water (distilled or deionized) and water-based paints.
The liquids that can be used in concrete cases depend on the pump. You can find information on this in the respective brochures, or you can contact us.
Our screw pumps are self-priming due to the way they work.
Sealless Spandau immersion pumps are basically not self-priming. The 1st impeller has to be wetted for the starting procedure.
Due to the way they work, centrifugal pumps even deliver when they run opposite to the specified direction of rotation. But only 1/3 of the required volumetric flow is reached. Damage to the pump due to the wrong direction of rotation can be largely ruled out. The direction of rotation in the case of screw pumps is much more critical. They are destroyed if they are run in the wrong direction of rotation. If no liquid is delivered and there is thus no lubrication of the pump’s hydraulic system, the pump will run "dry". The drastic increase in temperature of the hydraulic components leads to immediate and irreparable destruction of the screws and the casing’s coating.
Pumps generally require a shaft seal. These shaft seals are very sensitive to contaminated liquids and dry running. So the seal is the main wearing part of a pump. Most pump failures are due to defective seals. The design of sealless pumps makes it possible to dispense with a shaft seal. With these pumps the impeller sits on an extended motor shaft. Since it is used as an immersion pump, the controlled leakage remains in the tank or reservoir. Thanks to the sealless design of Spandau immersion pumps it is possible for them to run dry to a limited extent.
Spandau Pumpen is one of the few manufacturers worldwide able to make sealless pumps that are reliable at operating pressures as high as 25 bars.
With this pump there are three screws next to each other in the discharge casing. The primary screw, or drive screw, in the middle forms the pumping cavity together with the two secondary screws when they mesh.
The rotation of the set of screws opens up cavities on the suction side which the liquid in the pump flows into. The liquid is forced via the screws’ angular momentum through the closing cavities to the pump’s pressure port.
Since this principle corresponds to a piston constantly moving in one direction, the result is an even, surge-free volumetric flow.
The maximum achievable pressure is limited by the mechanical strength of the components, but primarily by the motor power.