SCM
Details
GeneralType SCM is a magnetic driven multistage, self priming horizontal side-channel pump. The side-channel pump with its high differential head has the advantage of operating more economically than normal centrifugal pumps for low capacity and high head applications. Side-channel pumps are suitable for solving many pumping problems in the chemical and petrochemical process industries. The SCM-pump is a heavy-duty sealless magnetic driven unit for handling clean liquids free from solids and is designed to improve plant and personnel safety, especially when handling toxic, explosive or other dangerous liquids which react on contact with the atmosphere. The static shroud (containment shell) replaces the requirement for double mechanical seals with external fluid reservoirs or barrier fluid circulating systems. Due to the fact that 90% of pump failures and repair requirements are caused by leaking mechanical seals, the sealless design saves considerable maintenance and spare parts costs. The maximum allowable working pressure is 600 PSI and maximum temperature is 240 degrees C. ConstructionThe SCM pumps are single or multistage, horizontal side-channel pumps in heavy duty design with end suction and vertical discharge flange. The pump shaft is driven via a permanent magnetic coupling. The static shroud forms a closed system with hermetically sealed liquid end. Suction and pressure disksThe suction and pressure disks are sealed to the atmosphere by confined O-rings, metal to metal fit, to prevent blowouts. In the shaft area, floating graphite impregnated PTFE-inserts are located for prevention of shaft deflection. The differential head is generated in the side-channel of the pressure disk. Side-channel impellersThe star-shaped side-channel impellers are rotating between the suction and pressure disks in a floating position on the pump shaft. No hydraulic thrust loads exist. Torque transmission between shaft and impeller is by keys. Pump shaftThe large diameter shaft does not deflect in operation and carries only minimum torsional load. Thus, wear-free running of the impellers is ensured. Outer ball bearingsThe drive shaft is carried in generously dimensioned anti-friction bearings protected by a radial seal ring. These bearings rarely need unscheduled replacement. with L-10 rating in excess of 3 years. Oil bath bearing housing is an option for pumps with 50 and 65-mm (2 and 3") discharge flange. Internal slide bearingsThe internal bearings are of the sleeve type, positioned in the pumped liquid. Standard material for shaft sleeves and thrust bearings is pure Silicon Carbide, highly resistant against corrosion and wear. Standard material for the stationary bearings is carbon but Silicon Carbide is also available on request. Suction impellerTo achieve low NPSH-conditions, a centrifugal impeller with enlarged eye area is located on the suction side. DiffuserSince these pumps can handle relatively large amounts of gas, they are inherently self priming as long as sufficient liquid remains in the pump. The diffuser is designed as a retaining stage which enables the pump to self-prime when re-started. NPSH conditionsWhen handling boiling liquids or hydrocarbons, the required liquid level on the suction side (NPSHR) can be reduced to 50% of the NPSH-value for water. Hazardous area featuresUnlike Canned-motor designs, magnetic driven pumps do not have electric windings adjacent to the fluid in the shroud and the power transfer by magnet flux is inherently safe. Magnetic coupling
|
Pump part |
Material |
|
Suction and
Pressure casing |
Ductile
iron GGG40.3, S.S.1.4408 |
|
Suction and
Pressure disk |
Ductile
iron GGG40.3, S.S.1.4408 |
|
Impeller |
S.S.
1.4408, Bronze G-Sn3z |
|
Pump Shaft |
Chromium
steel 1.4021, S.S.1.4571 |
|
Bearing
bracket |
Ductile
iron GGG 40.3 |
|
Shroud |
S.S.1.4571,
Hastelloy C4 |
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