Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)
Double-Case Pumps 209 Figure 12-3. Diffuser-type in-line impeller, double-case pump with balance disk (courtesy Ingersoll-Rand Company). • High pressure oil field water injection and offshore hydrocarbon eondensate reinjection pumps. * Pipeline pumps for unusually high pressures, very high vapor pressure hydrocarbons (typically above 200 psi), or offshore hydrocarbon condensate. Boiler Feed Pumps The most common application for double-case pumps is for boiler feed service in fossil-fueled power plants. These pumps must combine high efficiency with maximum reliability. Feedwater pump outages were estimated to have cost more than $408 million in replacement power alone in the United States in 1981 [3]. Several multi-million dollar efforts to reduce this cost have been implemented by users and manufacturers worldwide. These efforts have resulted in increased product knowledge that now can be applied to high-energy pumps, system design, and operation. Research in this area is continuing. Charge Pumps Oil refinery charge pumps handle liquids that are flammable and often toxic, at very high temperatures and pressures. Wide variations in viscosity of the feed stock or the presence of abrasives may add to pump design problems. In spite of inherent application problems, these pumps must combine maximum reliability with good efficiency.
210 Centrifugal Pumps: Design and Application Waterflood Pumps Oil field water injection pumps operate at capacities to 5,000 gpm. Double-case pumps provide differential heads to 11,000 feet and discharge pressures to 8,000 psi from two pumps operating in series. This application is covered in more detail in Chapter 10. Pipeline Pumps The vast majority of pipeline pumps are of the horizontally split, multistage design, covered in Chapter 10. Double-case pumps are used only when unusually high pressures are required or when handling hydrocarbons near their supercritical condition. Design Features Removable Inner Case Subassembly Modern double-case pumps have a fully separate inner case subassembly (including rotor). The inner case subassembly for a volute-type pump is shown in Figure 12-4. This subassembly can be removed, after disassembling the outboard cover, without disturbing the suction piping, discharge piping or the driver. It is common practice to have a spare subassembly available for replacement, thereby reducing maintenance turnaround time or the downtime caused by unscheduled outages. If the pumped fluid is hot, time is needed to lower the temperature of the components before maintenance work can begin. Time to cool by ambient air is extended because the pump is normally well insulated. Forced liquid cooling can be helpful, but must be preplanned to avoid subjecting the pump to unacceptable thermal gradients. In some designs the inner case subassembly includes the radial and thrust bearings. This feature further reduces downtime because the replacement rotor is aligned before the outage. A boiler feedwater pump of this construction, called "cartridge," "full cartridge," "pullout," or "cartridge pullout" design, is shown in Figure 12-5. A saltwater injection pump with full cartridge pullout is shown in Figure 12-6. The configuration shown is said to save at least 40 manhours of labor, compared to conventional construction, each time the inner-case subassembly is replaced. This design features a springplate on the high pressure end to preload the internal gasket between the inner volute case and the outer barrel. This gasket seals the full differential pressure. The springplate design compensates for manufacturing tolerances to assure interchangeability among spare inner assemblies and also compensates
- Page 174 and 175: Pipeline, Waterflood and CO 2 Pumps
- Page 176 and 177: Pipeline, Waterflood and CO 2 Pumps
- Page 178 and 179: Pipeline, Waterflood and COa Pumps
- Page 180 and 181: Pipeline, Waterflood and CO 2 Pumps
- Page 182 and 183: Pipeline, Waterflood and COa Pumps
- Page 184 and 185: Pipeline, Waterflood and COa Pumps
- Page 186 and 187: Pipeline, Waterflood and CO 2 Pumps
- Page 188 and 189: 11 By Edward Gravelle Sundstrand Fl
- Page 190 and 191: High Speed Pumps 175 History and De
- Page 192 and 193: High Speed Pumps 177 Figure 11-2. (
- Page 194 and 195: High Speed Pumps 179 some portion o
- Page 196 and 197: High Speed Pumps 181 This is to say
- Page 198 and 199: High Speed Pumps 183 This expressio
- Page 200 and 201: High Speed Pumps 185 Figure 11-3. P
- Page 202 and 203: High Speed Pumps 187 As an aside, p
- Page 204 and 205: High Speed Pumps 189 Figure 11-5. I
- Page 206 and 207: High Speed Pumps 191 Figure 11-7. I
- Page 208 and 209: High Speed Pumps 193 Figure 11-9. R
- Page 210 and 211: High Speed Pumps 195 Figure 11-10.
- Page 212 and 213: High Speed Pumps 19? Figure 11-11.
- Page 214 and 215: High Speed Pumps 199
- Page 216 and 217: High Speed Pumps 201 Figure 11-13.
- Page 218 and 219: High Speed Pumps 203 nal bearings a
- Page 220 and 221: High Speed Pumps 205 Barske, U, M.,
- Page 222 and 223: Double-Case Pumps 207 jected to ext
- Page 226 and 227: Double-Case Pumps 211 Figure 12-4.
- Page 228 and 229: Double-Case Pumps 213 ally by split
- Page 230 and 231: Double-Case Pumps 215 The throttle
- Page 232 and 233: Figure 12-11. pump for 4,000 psi In
- Page 234 and 235: Double-Case Pumps 219 so that the t
- Page 236 and 237: Double-Case Pumps 221 Figure 12-12.
- Page 238 and 239: Doubte-Case Pumps 223 Volute Casing
- Page 240 and 241: Double-Case Pumps 225 5. Survey of
- Page 242 and 243: Slurry Pumps 227 An approximate com
- Page 244 and 245: Slurry Pumps 229 Figure 13-2. Nomog
- Page 246 and 247: Slurry Pumps 231 Table 13-2 Alloys
- Page 248 and 249: Slurry Pumps 233 Figure 13-3. Class
- Page 250 and 251: Figure 13-4, (A) (B) (C)
- Page 252 and 253: Slurry Pumps 237 There is little to
- Page 254 and 255: Figyre 13-7, (courtesy Pumps, Inc.)
- Page 256 and 257: Flgyr« 13-8, with (courtesy Goulds
- Page 258 and 259: Slurry Pumps 243 ing the pump speed
- Page 260 and 261: Slurry Pumps 245 Where there exists
- Page 262 and 263: Hydraulic Power Recovery Turbines 2
- Page 264 and 265: Hydraulic Power Recovery Turbines 2
- Page 266 and 267: Hydraulic Power Recovery Turbines 2
- Page 268 and 269: Hydraulic Power Recovery Turbines 2
- Page 270 and 271: Hydraulic Power Recovery Turbines 2
- Page 272 and 273: Hydraulic Power Recovery Turbines 2
210 <strong>Centrifugal</strong> <strong>Pumps</strong>: <strong>Design</strong> <strong>and</strong> <strong>Application</strong><br />
Waterflood <strong>Pumps</strong><br />
Oil field water injection pumps operate at capacities to 5,000 gpm.<br />
Double-case pumps provide differential heads to 11,000 feet <strong>and</strong> discharge<br />
pressures to 8,000 psi from two pumps operating in series. This<br />
application is cover<strong>ed</strong> in more detail in Chapter 10.<br />
Pipeline <strong>Pumps</strong><br />
The vast majority of pipeline pumps are of the horizontally split, multistage<br />
design, cover<strong>ed</strong> in Chapter 10. Double-case pumps are us<strong>ed</strong> only<br />
when unusually high pressures are requir<strong>ed</strong> or when h<strong>and</strong>ling hydrocarbons<br />
near their supercritical condition.<br />
<strong>Design</strong> Features<br />
Removable Inner Case Subassembly<br />
Modern double-case pumps have a fully separate inner case subassembly<br />
(including rotor). The inner case subassembly for a volute-type<br />
pump is shown in Figure 12-4. This subassembly can be remov<strong>ed</strong>, after<br />
disassembling the outboard cover, without disturbing the suction piping,<br />
discharge piping or the driver. It is common practice to have a spare subassembly<br />
available for replacement, thereby r<strong>ed</strong>ucing maintenance turnaround<br />
time or the downtime caus<strong>ed</strong> by unsch<strong>ed</strong>ul<strong>ed</strong> outages.<br />
If the pump<strong>ed</strong> fluid is hot, time is ne<strong>ed</strong><strong>ed</strong> to lower the temperature of<br />
the components before maintenance work can begin. Time to cool by ambient<br />
air is extend<strong>ed</strong> because the pump is normally well insulat<strong>ed</strong>. Forc<strong>ed</strong><br />
liquid cooling can be helpful, but must be preplann<strong>ed</strong> to avoid subjecting<br />
the pump to unacceptable thermal gradients.<br />
In some designs the inner case subassembly includes the radial <strong>and</strong><br />
thrust bearings. This feature further r<strong>ed</strong>uces downtime because the replacement<br />
rotor is align<strong>ed</strong> before the outage. A boiler fe<strong>ed</strong>water pump of<br />
this construction, call<strong>ed</strong> "cartridge," "full cartridge," "pullout," or<br />
"cartridge pullout" design, is shown in Figure 12-5.<br />
A saltwater injection pump with full cartridge pullout is shown in Figure<br />
12-6. The configuration shown is said to save at least 40 manhours of<br />
labor, compar<strong>ed</strong> to conventional construction, each time the inner-case<br />
subassembly is replac<strong>ed</strong>. This design features a springplate on the high<br />
pressure end to preload the internal gasket between the inner volute case<br />
<strong>and</strong> the outer barrel. This gasket seals the full differential pressure. The<br />
springplate design compensates for manufacturing tolerances to assure<br />
interchangeability among spare inner assemblies <strong>and</strong> also compensates