N/A Ball Bearings
The pump shaft is carried on discharge side, outside the pumped liquid in generously dimensioned grease lubricated antifriction bearings.
The lubrication is effected by grease-nipples, fitted to the bearing cover.
The bearings are protected against any product leakage by deflectors and bearing bracket.

Sleeve Bearings on Suction Side
These bearings are positioned in the pumped liquid. Standard material for shaft sleeve is pure Silicon Carbide.
Radial stationary sleeve bearings are made of antimony- impregnated carbon. Diamond-coated SiC available as an option.

N/A Side-channel Impellers
The star-shaped side-channel impellers are rotating between suction and pressure disks in floating position on the pump shaft.
No hydraulic thrust loads exist. Torque transmission between shaft and impeller by keys.

Suction Impeller
To achieve low NPSH-conditions, a centrifugal impeller with enlarged eye area is located on suction side.

N/A Dry Running Protection
Due to the tight clearance between the side-channel impellers and the stage disks, this type of pump will not tolerate dry running.
For protection, a level control in the suction line is recommended. At selfpriming conditions with a suction liquid level below pump centerline,
an optoelectronic level detector can be fitted in the diffuser to monitor the required liquid level in the pump.

N/A Construction
The SCM-pumps are single or multistage, horizontal side channel pumps in heavy duty design with end suction and vertical discharge flanges. Flanges and casings are designed for a maximum allowable working pressure of 40 bar or 600 psi.

Suction- and Pressure Disks
The suction and pressure disks are sealed to the atmosphere by confined O-rings, metal to metal fit, to prevent blow outs. In the shaft area, floating graphite impregnated PTFE-inserts are located for prevention of shaft deflection and seizing. The differential head is generated in the side-channel of the pressure disk.

Pump Shaft
The large diameter shaft is carried in slide bearings and has no deflection and only minimum torsional load. Thus, wear-free running of the impeller is ensured.

Diffuser
Since these pumps can handle relatively large amounts of gas, they are inherently selfpriming as long as sufficient liquid remains in the pump. Therefore, the diffuser is also designed as a retaining stage. That means, the pump will still be filled with liquid after switch off and can be restarted without problem also in self-priming service.

NPSH-Conditions
The NPSH-conditions displayed on the next page are based on water at 20°C (65°F). When handling boiling liquids or hydrocarbons, the liquid level on suction side can be reduced to 50% of the NPSH-value.

N/A Materials
Depending on the requirements, the following materials are provided for SC-pumps. Special designs on request.

Pumps Parts Material

Pump Part Suction-and pressure casing Material Ductile Iron (GGG40.3), 316 ss (1.4408, G-X5 CrNiMo 18.10)
Pump Part Suction- and pressure disk Material GGG40.3 1.4408 (G-X5 CrNiMo 18.10)
Pump Part Impeller Material G-SnBz 1.4457 (G-X25 CrNiMo 25.9)
Pump Part Pump shaft Material 1.4021 (X20 Cr 13) 1.4571 (X10 CrNiMoTi 18.10)
Pump Part Bearing bracket Material GGG40.3

N/A Shaft Sealing

The seal chambers of SC-pumps are designed to accept - besides gland packings - all common mechanical seal systems. Changing from gland packing to single or double acting seals is possible, even on site, without any remachining of the originally delivered pump parts. The diameter of mechanical seals comply with the preferential sizes 24, 28 and 33 mm according to DIN 24960.

For handling toxic, explosive or other dangerous liquids which react on contact with the atmosphere, the sealless magnetic driven SCM-series are also available. More information about this design available on request. Some of the possible shaft sealing systems are displayed by the following sectional drawings.