Page 200 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Pumping of Liquids 171

Turn Pump Over by Hand before Starling No. Parr Nome
Molar lo Ht Iha! II Turn1 Freely.
I. Pump Co&ing
3. Impeller
Lubricate Stuffing Box 4. Pump Frome
By Circulating Water or 7. Split Gland
Clear Solution lhru 10. Shoff
Connections •x• a •y•. 12. Lantern Ring
13. Pocking
44. Nipple (2)
Tong of Key 55. Thrower Ring
Must be Located 56. Rubber Ring
Here 59. Re&ilient Sleeve
60. S hafl Sleeve
61. Rubber Ring
62. Retaining Ring
74. Rubber Ring
79. Cop&crew (6)
82. Gland Yoke
88. Key
98. Shafi Sleeve Ext'n.
106. Tie Rod
144. Key
164. Wosher (2)
165. Retainer (2)
167. Rubber Ring (2)

Figure 3-16. Stuffing box details lined pump with porcelain or teflon® shaft sleeve. (Courtesy Dorr-Oliver, Inc.)

nent damage or destruction on only one or two revolu-
tions at pump speed. The seals should be inspected and
cleaned immediately prior to initial start-up.

A mechanical seal system (see Figures 3-l 9A [23] and
3-19B [16]) contains a rotating element attached to the
rotating shaft by set screws ( or a clamp) that turns against
a stationary unit set in the gland housing. The necessary
continuous contact between the seal faces (see Figure 3-
l 9A) is maintained by hydraulic pressure in the pump
from the fluid being pumped and by the mechanical load- Longitudinal section with Lantern Gland.
ing with springs or bellows. To seal the mechanical seal
elements to the rotating shaft to prevent leakage along
the shaft, two basic types of seals are used: (a) pusher type
using springs and seal "O" rings, wedge rings, etc. and (b)
non-pusher type using some form of bellows of elastomer
or metal [24]. Also see Table 3-4. Pocking

The matching contact rubbing faces are made of dis- Throat Bushino
similar materials, precision finished to a mirror-like flat
surface. There is little friction between these, and hence,
they form a seal that is practically fluid tight. The rubbing
materials may be some combination of low friction car-
bon, ceramics (aluminum oxide, silicon carbide), and/or
tungsten. The choice of materials will depend on the ser-
vice, as will the selection of the materials of construction
for the other components, such as springs, "O" rings, Gland
other seal rings, and even the housing. The designer Box Gland
should consult the seal manufacturers for details of appli-
cation not possible to include here. Figure 3-17. Packed stuffing box. (Courtesy Dean Brothers Pumps, Inc.)