Sump pumps

The layout specialist should be aware of any special space requirements for a pump. Otherwise, pumps are usually fitted into a small area normally considered adequate for a general pump service. Sump pumps and other special types of appHcations need to be called out. 

Sump Pumps These are small single-stage vertical pumps used to drain shahowpits or sumps. They are of the same general construction as vertical process pumps but are not designed for severe operating conditions. 

In-house correlation of pumps should be made using gpm vs. cost with head as a parameter. These should result in step functions, since one size pump with different impellers can serve several flow rates and heads. Different correlations should be made for each type of pump. The price of a vertical multistage pump may be quite different from a horizontal splitcase multistage pump. A sump pump with a 15-ft drive shaft would cost more than a single-stage horizontal pump with the same gpm and head. 

The arrangement and dimensions indicated in Figure 3-62 or Figure 3-63 are satisfactory for single or multiple pump installations. (For more details, refer to Reference [17]). A few key points in sump-pump relationships for good non-vortexing operation are ... 

Bell diameter of vertical sump pump, ft = Brake horsepo ver... 

The 4-ft-circular Supracell DAF was used for this testing. The flotation area is 10 ft2. Maximum hydraulic loading is 30 U.S. gpm. The unit was set up adjacent to the aeration basin at the waste treatment plant. A small sump pump was used to pump mixed liquor to the Supracell DAF. 

Drain to daylight if possible, or to a drywell or sewer. If you must use an interior sump pump, seal it. 

Unless otherwise specified, except for volute sump pumps (Type VS4), the first stage impeller shall be located between bearings. 

Vertically snspended cantilever sump pumps are designated as Type VS5. 

For open system sump pump service, the pressure containing components Types VS4 and VS5 pumps are the volute casing, suction cover, and discharge fine. For closed system pressurized or vacuum tank service, the outer stuffing box or seal housing, pump cover plate, and tank cover also become pressure containing components. 

Install an enclosed wash rack for equipment in an adjacent structure with drain connected through a sump (pump installed) for disposal of wash water from tank and equipment. Wash rack must have a cleanout trap for removal of soil and other debris from equipment. 

Bilge pumps, sump pumps, etc. (float switches)... 

Vertically-suspended, single-casing volute line-shaft driven sump pumps are designated pump type VS4. 

TPU-116 liner, single pack (burner), an ultraviolet flame scanner, a TPU sump pump, a scrubber demister pad, inlet water filters, and an inlet recirculation valve (D17789D, p. 40). 

SEMATECH estimated that the 5-year cost of operation for the prototype unit abating four-chamber exhausts containing PECs was 83,000/ year based on an 83% TPU operation while the commercial TPU cost of operation was 77,000/ year based on 100% TPU operation. The scrubber s once-through waster usage of 8 gal/min represents the major utility cost. It was assumed that a commercial facility would have lower electrical costs by eliminating the booster pump and extra sump pump (D17789D, pp. 9, 44). Table 1 discusses the annual utility costs associated with the industrial unit. 

The culprit turned out to be manure, all right, but of a decidedly human variety. The building s toilets connected to a septic tank, with the usual u-shaped trap built into the pipes. These traps are normally filled with water, which prevents any gas from backing up into the toilet bowl. Since septic tanks create the anaerobic conditions under which flammable methane can be generated, this is an essential safety measure. The toilets had not been used since the station was abandoned, and the water had evaporated from the plumbing system. Methane was now free to back up into the basement, and it had apparently done so. As the original investigator had proposed, a spark from the sump pump had probably set off the explosion. The bats had been falsely accused. 

The most common type of pump used is the sump pump shown in Fig. 25.8. The vast majority of the pumps in the world are of this type. They are the sort of pumps used to pump water out of shallow wells and from irrigation ditches. In New Orleans, we use thousands of these pumps to push rainwater over the levees and into the mighty Mississippi River. 

Sump pumps can draw water up from levels as much as 30 ft below the pump s suction. But do such pumps require NPSH Absolutely All centrifugal pumps have some NPSH requirements. What, then, is the available NPSH to the sump pump shown in Fig. 25.8 ... 

Where, then, does the available NPSH to a sump pump really come from It comes from atmospheric pressure. Atmospheric pressure, at sea level, is equivalent to... 

The only real difference between a sump pump and an ordinary centrifugal pump is that the sump pump is more difficult to prime than the ordinary pump. 

An industrial example requiring simple sequence logic is the effluent tank with two sump pumps illustrated in Fig. 8-59. There are two sump pumps, A and B. The tank is equipped with three level switches, one for low level (LL), one for high level (LH), and one for high-high level (LHH). All level switches actuate on rising level. The logic is to be as follows ... 

When level switch LH actuates, start one sump pump. This must alternate between the sump pumps. If pump A is started on this occasion, then pump B must be started on the next occasion. 

When level switch LHH actuates, start the other sump pump. 

When level switch LL deactuates, stop all sump pumps. 

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