Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

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15 by Frederic W. Buse Ingersolf-Rand Company Chemical Pumps Metallic and Nonmetallic Chemical pumps are designed for many processes and products that are not normally handled by pumps designed for a single product or process such as general water pumps, boiler feed pumps, cooling water pumps, or petroleum industry pumps. The chemical processes vary from acids, alkalies, toxics, reducing agents, oxides, slurries, organics, or inorganics causing corrosion, erosion, galvanic action, or leaching to occur on the pumps and piping system and any other product in the process. To handle this variety of conditions, the pumps employ various materials such as 316 stainless steel, ductile iron, alloy 20, titanium, Hastelloy B and C. The continuous development of nonmetallics also make these pumps available in vinyl esters, epoxies, PVC, or with linings of teflon. Some pumps employ carbon, ceramic, and glass bodies or linings. Specifications ANSI Pumps Most chemical pumps in the United States in the past 25 years have been developed according to the ANSI B73.1M and .2M specifications for horizontal and vertical pumps respectively (Figures 15-1 and 15-2). These specifications were initially developed in 1955 and were published in 1962. The current specifications were published in 1991. Besides safety criteria, the main objective for these specifications was to establish dimensional standards and interchangeability of various size pumps 283

284 Centrifugal Pumps: Design and Application Figure 15-1. ANSI overhung single-stage pump (courtesy of Ingersoll-Rand Company). within a given envelope (Figure 15-3A). The ANSI B73.1M specification has a dimensional designation of AA to A120 that covers 19 various size pumps. Its dimensional standards not only cover the pump itself, but also cover the pumps on bedplates. ANSI B73.2M has a dimensional designation of 2015 to 6040 that covers 15 various size pumps (Figure 15 3B). This dimensional standard became an important criterion for chemical plant designers because they could rely on the pump envelopes for dimensional accuracy when laying out the piping and foundations for the pumps. This eliminated the need for certified drawings of the pump assembly or pump bedplate combination from the pump suppliers. It also eliminated the need for extra inventory for spare parts because spare pumps could be purchased from various pump manufacturers with the assurance that they would fit into an existing piping system. The hydraulic range of these pumps at a synchronous speed of 3600 RPM is 2000 gallons per minute and over 800 feet. At 1800 synchronous speed, the range is from 3500 gallons per minute to 250 feet (Figures 15-4 and 15-5).

284 <strong>Centrifugal</strong> <strong>Pumps</strong>: <strong>Design</strong> <strong>and</strong> <strong>Application</strong><br />

Figure 15-1. ANSI overhung single-stage pump (courtesy of Ingersoll-R<strong>and</strong><br />

Company).<br />

within a given envelope (Figure 15-3A). The ANSI B73.1M specification<br />

has a dimensional designation of AA to A120 that covers 19 various<br />

size pumps. Its dimensional st<strong>and</strong>ards not only cover the pump itself, but<br />

also cover the pumps on b<strong>ed</strong>plates. ANSI B73.2M has a dimensional designation<br />

of 2015 to 6040 that covers 15 various size pumps (Figure 15<br />

3B). This dimensional st<strong>and</strong>ard became an important criterion for chemical<br />

plant designers because they could rely on the pump envelopes for<br />

dimensional accuracy when laying out the piping <strong>and</strong> foundations for the<br />

pumps. This eliminat<strong>ed</strong> the ne<strong>ed</strong> for certifi<strong>ed</strong> drawings of the pump assembly<br />

or pump b<strong>ed</strong>plate combination from the pump suppliers. It also<br />

eliminat<strong>ed</strong> the ne<strong>ed</strong> for extra inventory for spare parts because spare<br />

pumps could be purchas<strong>ed</strong> from various pump manufacturers with the<br />

assurance that they would fit into an existing piping system.<br />

The hydraulic range of these pumps at a synchronous spe<strong>ed</strong> of 3600<br />

RPM is 2000 gallons per minute <strong>and</strong> over 800 feet. At 1800 synchronous<br />

spe<strong>ed</strong>, the range is from 3500 gallons per minute to 250 feet (Figures<br />

15-4 <strong>and</strong> 15-5).

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