Page 197 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

168 Applied Process Design for Chemical and Petrochemical Plants

PARTS LIST
Cat.
No. Part Name
2-F First Stage Impeller
2-S Second Stage Impeller and Above
34 Nozzle Head Bushing
260 Diffuser Ring
298 Suction Bell Ring
8 Stvfflng Box lushing
9-L Lower Shaft Sleeve
Inlet
9.1 Intermediate Shaft SIHve
9-U Upper Shaft SIHve
910 34 12 Packing
13 Seal Cage
14 Gland
2.57·1 171 14-A Gland Bolt
31 Complete Coupling
61-P Pump Half Coupling Lock Nut
223 7 61-M Motor Half Coupling Loclc Nut
62 Complete Piping
73 Stuffing Box
218 89 Ba lance Disk
140 Motor Support Column
146 Diffuser
2-S 162-F ht. Stg. Impeller Retaining Collar
162-S 2nd Stg. and Above Impeller Retaining
Collar
162·5 171 Nozzle Head
175 Sudion llell
190-L lower Sleeve Bearing
U6 190-U 190-U Upper Sleeve Bearing
218 Tank
223 Spacer Column
237-F 162-f 237-F First Stage Snap Ring
237-S Second Stage Snap Ring and Above
257-L Lower Gasket
190-L 298 257-1 lntennedlate Gasket
257-U Upper Gasket
257-S llllnd Flange Gasket
7 Shaft with Keys
175
910 lllnd flange
Figure 3-9. Vertical multistage centrifugal pump with barrel casing. (Courtesy Allis-Chalmers Mfg. Co.)

the proper corrosion resistant material over the preferred Packing and Seals on Rotating Shaft
structural shaft material. These sleeves may be metal,
ceramic, rubber, etc., as illustrated in Figure 3-16. Conventional soft or metallic packing in a stuffing box
(Figure 3-17) is satisfactory for many low pressure, non-
Bearings corrosive fluid systems. Special packings such as teflon, or
mechanical seals are commonly used for corrosive fluids,
since there can be leakage through the packing along the
The bearings must be adequate to handle the shaft
loads without excessive wear, provided lubrication is main- rotating shaft. However, for these conditions a mechanical
seal is preferred. When the pressure becomes high (above
tained. Usually this is not a point of real question provid- about 50 psig) or the fluid is corrosive, additional means
ed the manufacturer has had experience in the type of of sealing the shaft must be provided. Particular care must
loads imposed by the service conditions, and the respon- be taken in handling and using the mechanical seals, and
sibility for adequate design must be his.
these special instructions should be obtained from the seal
In all cases, the bearings should be of the outboard manufacturer [27]. Generally speaking it is not wise to
type, that is, not in the process fluid, unless special condi- have the mechanical seal installed at the pump factory, as
tions prevail to make this situation acceptable. the slightest amount of grit on the faces can cause perma-