Page 201 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

174 Applied Process Design for Chemical and Petrochemical Plants
2 N.P.T's for Circulating
/Lubrication I

Figure 3-26. Circulating lubrication. (By permission, H. P. Hummer
and W. J. Ramsey, Bulletin SD 752, O&T3 Durametallic Corp.)

r- --- -- - -- 7-
I
or By-pass from Discharge

Figure 3-24. Gland plate cooling. (By permission, H. P. Hummer and Figure 3-27. Flushing inside seal. (By permission, H. P. Hummer and
W. J. Ramsey, Bulletin SD 752, O&T, Durametallic Corp.)
W. J. Ramsey, Bulletin SD 752, O&T, Durametallic Corp.)
I NIT, for Dead-End I-------
/ Lubrication Product Recirculat

Figure 3-25. Dead-end lubrication. (By permission, H. P. Hummer Figure 3-28. Flushing outside seal. (By permission, H. P. Hummer
and W. J. Ramsey. Bulletin SD 752, O&T, Durametallic Corp.) and W. J. Ramsey, Bulletin SD 752, O&T, Durametallic Corp.)

Generally speaking the centrifugal pump has these char- 6. Develops turbulent conditions in fluids
acteristics: 7. Turbine type: (a) offers very high heads at low flows,
(b) self-priming, (c) limited to very clean, non-abra-
1. Wide capacity, pressure, and fluid characteristics sive fluids with limited physical properties, (d) clear-
range ances can be problem on assembly and maintenance.
2. Easily adapted to direct motor, V-belt or other drive
3. Relatively small ground area requirements Single-Stage (Single Impeller) Pumps
4. Relatively low cost
5. Difficult to obtain very low flows at moderate to high This type of pump (Figures 3-1, 3-2, 3-3) is the work-
pressures horse of the chemical and petrochemical industry. It also