Centrifugal pumps with magnetic coupling - overview​​
Classification
Centrifugal pumps are flow pumps. The pumps manufactured by Sager + Mack are axial-flow, normal-priming, single-stage centrifugal pumps.
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Construction
Pump head made of plastic or stainless steel, with welded connections (flange / screw connection / hose nozzle). Special tubular impeller on stainless steel shaft (not in contact with media).
Shaft with plain bearings (radial and axial) with high-quality plain bearings made of silicon carbide (SIC).
The magnets of the inner magnet, enclosed in the resistant material, are seated on the shaft.
Free suction mouth without resistances affecting NPSH.
By using solid material for the wetted parts, these pumps offer very smooth running, high corrosion resistance and diffusion density, as well as robustness against abrasion and thermal distortion, therefore these machines are considered very safe to operate, reliable and leak-free.
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Functionality
The liquid flowing in axially is accelerated by the rotary motion of the impeller and conveyed to the discharge side with higher pressure.
The motor transmits power to the pump shaft via magnetic forces between the outer magnet and the inner magnet, which are separated physically and hermetically by the containment can.
The delivery pressure as well as the delivery rate are determined by the pump performance (pump characteristic curve), the impeller geometry as well as the suction- and pressure-side pressure losses of the system. The delivery rate as well as the delivery pressure can also be varied by speed control or bypass solutions.
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Power range
Pressure: 0 to 6 bar
Flow rate: 0 to 120 m^3/h
Viscosity: up to 100 mPas
Temperature: 5 to 95 °C (plastic) / 0 to 120 °C (stainless steel)
Power: 0.8 kW to 9.2 kW
Solids content: up to 25
Solids size: depending on pump size
Suction lift: not self-priming
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Applications
Centrifugal pumps with magnetic coupling made of plastic or stainless steel are mostly used as transfer pumps or circulation pumps. They are used in numerous processes, often in the use of environmentally hazardous, corrosive substances or liquids, such as acids, alkalis or chemicals in general.
Normal-priming centrifugal pumps are not self-priming and therefore require a certain pre-pressure (usually realised via an inlet head) in order not to fall below the required NPSH value.
The special impeller geometry of the centrifugal pumps from Sager+Mack offers advantages in the area of contaminated media with solids content. This impeller geometry also produces a relatively flat pump characteristic curve, which provides process advantages in many applications.
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Sealing technology
Power is transmitted from the motor to the pump shaft by means of a magnetic coupling.
The pump head is thus statically sealed to the containment can by means of a media-resistant O-ring. There is no rotating seal to the outside. Magnetically coupled pumps are therefore considered to be leak-free.
(Special designs are also available with single-acting mechanical seals on request).
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Materials
Plastic (PP/PVDF), stainless steel (V4A), other special materials on request.
All parts in contact with liquids are, after prior design, media-resistant incl. the matching sealing materials.