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.
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.
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.
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.