Pumps installation

When a pump installation is being designed, the avail le net positive suction head (NPSH) must be equal to or greater than the (NPSH)r for the desired capacity. The (NPSH) can Be calculated as follows ... 

These motors have a lower efficiency as a result of running in liquid, causing more liquid drag and also axial thrust bearing loss, which is also a part of the motor. However, this lower efficiency of the motor is compensated by fewer mechanical and hydraulic losses in a submersible motor-pump installation, compared to a vertical turbine pump installation. 

Sometimes you hear people say that the pump is operating off its cw. t velocity, the impeller diameter and design are correct, if the pump installed and functioning correctly, including the mechanical seal and impossible to operate off the curve. The pump will be somewhere on between shut-off head and maximum flow a zero elevation. 

At Pump Installation Be sure the motor shaft centerline is below the pump shaft centerline so that it can be shimmed upward. Make sure the motor mount boltholes have sufficient play to allow for some lateral adjustment. Many pumps and motor assemblies are shipped from the factory on a common channel iron base plate. The manufacturer alleges that they arc already aligned at the factory. You need to verify and correct this alignment in all cases. 

Figure 3-51. System head curves for single pump installation.

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 ... 

Pump Installation 627. Pump Operation 630. Pump Performance Charts 631. Mud Pump Hydraulics 631. Useful Formulas 645. 

As a further consideration of the overall system design, it is necessary to examine the choice of the number of pumps installed. In the petrochemical and process industries availability is an important factor in plant operation. The Institution of Mechanical Engineers suggests several classes of pumps linked to availability ... 

More pumps fail as a direct result of improper installation than any other single factor. The predominant reasons for these failures include starvation, caused by inadequate or inconsistent suction conditions distortion, caused by pipe strain or improper foundation and turbulent that results from piping or entrained gas problems. Centrifugal pump installation must follow Hydraulic Institute Standards, which provide specific guidelines to prevent these installation and performance problems. This chapter will address the fundamental requirements for proper installation. 

Very few pump installations follow Hydraulic Institute recommendations. A minority of installations fail to follow reasonable engineering practices or even common sense. Therefore, it should not be a surprise that centrifugal pump applications often exhibit chronic reliability and maintenance problems. 

A pump installed on a well can pump at a maximum rate of 100 gallons per minute. If the town requires 15,000 gallons of water in one day, how long would the pump have to continuously run at 75% of its maximum rate to meet the town s need ... 

Where a significant lift is required such as offshore, several options are available such as a shaft driven, hydraulic drive or electrical submersible pump. Shaft driven vertical turbine pumps historically have been used extensively offshore, but recent reliability improvement with electrical submersible pumps and hydraulic drive units have been eagerly accepted as they eliminate alignment problems, topsides weight and in some instances are less complex than the right angle engine driven vertical turbine units. Hydraulic calculations for offshore pump installations must remember to account for tide and wave fluctuations. 

The recovery most often used at sites with significant quantities of recoverable LNAPL is the two-pump system. A submersible water pump installed below the lowest possible probable interface level is used to create a drawdown cone of depression, while a second pump is suspended with its intake port located at the oil-water interface. A typical two-pump system installation is shown in Figure 7.15. 

The pumping unit consisted of a submersible pump installed in a 10,000-gal reservoir tank, which also served as a holding tank (Figure 12.16). Fluids pumped from the wells were all returned to the tank for separation. All the oil and some water produced overflowed from the tank into another oil-water separator and then into the slop oil treatment system of the refinery. Clarified water from the bottom of the tank was recycled by the submersible pump through the eductor units to continue operations. 

The main refinery LNAPL recovery system consists of 11 single-pump 4- and 6-in.-diameter production wells. Recovery wells are constructed of slotted PVC screens and casing. For the recovery of LNAPL, 4-in.-diameter submersible pumps have been installed. The submersible pumps installed within the recovery wells are of stainless steel construction. These pumps were not adversely affected by water, hydrocarbon, or minor amounts of fine sand and silt produced by the recovery wells. 

In the case of operations ranging between 760 and 10 3 torr, the two-stage rotary pump is adequate. Ultimate vacuum, using the diffusion pump installation, is better than 10-6 torr. 

Obviously, in practical situations one can hardly imagine a vacuum pump installed onboard of a fuel cell-powered vehicle. Even if so, the membrane of a Proton Exchange Membrane Fuel Cell (PEMFC) will be soon contaminated by the oil vapors released from the pump (dry pumps are possible but this would enormously complicate the entire design). 

New fire water pump installations require acceptance testing as defined in NEPA 20. This section highlights some of the important tests required. 

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. 

Tests conducted on the Hutton produced-water system used a two-stage mono pump installed downstream of the produced-water flash lank, which collects water from first, second, and test separators under interface-level control. 

Pump installation is an important point to be carefully considered. In the case of vertical pumps, pump submergence should comply with the vendor s specifications. In the case of horizontal pumps, the designer should control the following points ... 

Investigators learned that one afternoon, a contractor entered the area to start a local ventilation fan in preparation for an unrelated nearby maintenance job. The electrical switch used to start the pump was identical to the type of switch used to start the ventilation fan. Although the switch was labeled, the tag was hard to read. These switches were over 50 feet from the outdoor caustic soda pump installation, well outside of the diked area. The pump continued to run, unnoticed by anyone. There was no instrument in an occupied location indicating that the pump was running. [12]... 

Figure 7-15 Heavily damaged condensate pump installation. Courtesy of Eastman...

Plastic Pumps Installed to Pump Flammable Liquids... 

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