This more efficient heat transfer method results in lower operating temperatures for the motor and its internal components, and helps extend the life of the motor. With a submersible pump, heat transfer is accomplished by direct conduction to the relatively constant temperature fluid being pumped. In a nonsubmersible pump, the primary means of motor heat dissipation is by convection to the ambient atmosphere.ĭepending on installation, this can vary from frigid temperatures with maximum heat removal to very high temperatures encountered on a summer day, made even hotter by a confined pit or building. Consideration should be made to connecting sump pumps to a standby power supply.Īn important advantage of the submersible pump is the added heat dissipation obtained from the motor being surrounded by the pumped medium. Normally duplex or triplex pump packages are provided, except where temporary outages are acceptable or there is no possibility of flooding. In some cases, the pump can be above the water level, but only if a reliable provision is included in the design to prime the pump prior to each pumping event. Pumps handling stormwater or subsurface drainage (not sanitary drainage) are not required to be sealed and vented to the outdoors and can open to the room. California 2540.10 automatically requires explosion-proof pumps and controls. The engineer needs to review the materials being pumped and the gaseous atmosphere being produced for any explosive characteristics. Normally, the installation of a pump in a sanitary drain system requires a sealed basin and vent piping to the exterior or to a vent stack. Grinder pumps are available in centrifugal and positive-displacement types. The other, referred to as a grinder pump, includes a set of rotating stainless-steel cutting blades upstream of the impeller inlet to slice solid contaminants as they pass through a ring with acute edges.Įfficiency is compromised in both types for the sake of effective waste transport, in the latter more so than in the former, but with the benefit of a reduced pipe diameter in the discharge piping. One design uses an open recessed impeller, no wear rings and clearance dimensions that allow 2-inch (50-mm) diameter spheres to pass through. Such a pump may be suitable for subsoil drainage or for greywater pumping.įor drainage flows from water closets and similar fixtures, manufacturers provide pumps of two designs. For minimal contaminants, the design may be with an enclosed impeller, wear rings and clearance dimensions that allow 3/4-inch (19-mm) diameter spheres to pass through. The nature of solids and other contaminants in the water handled by drainage pumps necessitates several types of pump designs. In any design, provision is required for air to enter or leave the basin as the water level varies.

Some pumps are designed to be submerged in the inlet basin and others in a dry pit adjacent to the basin in others, the motor is mounted above with only the pump casing and impeller submerged. The terminology varies to describe these pumps, but typical names include sewage pump, sump pump, sewage ejector, lift station pump, effluent pump, bilge pump, nonclog pump, drain water pump, solids-handling sewage pump, grinder pump, dewatering pump and wastewater pump.ĭrainage pumps generally have vertical shafts, cylindrical basins and indoor or outdoor locations. Lastly, if backflow is intolerable from floor drains in a high-value occupancy, pumps are provided for the floor drains. Elevation issues usually apply to subsoil drainage, so this water also is pumped. The issue may apply only to one fixture, one floor or the entire building. Where the elevation of the municipal or building sewer is insufficient or if another elevation shortfall occurs, drainage pumps are added to a drainage system.

Duplex sewage ejector pump systems