Page 191 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

164 Applied Process Design for Chemical and Petrochemical Plants

Heavv Dutv Volute )Confined Tvoe Gasket
'De Gland (Optional Construction)
Constant Level Oiler
Oil Breather
Thrust Beoring ;
Boll Type
-Shaft:Allov . - Steel
Seol Lantern-
Slinger ; Labyrinth Type

Enclosed TvDe *Radial Bearing;Ball Type
Water Jacket Cools Oil
bolanced f& Reservoir
Reduced Thrust
Load Slinger ; Labyrinth Type

t Sleeve (Optional Construction)
Vent and Drain(Optiono1) Back Plate; Water .Cooled Type,Extra Deep Stuffing Box

Figure 3-2. Cut-a-way section of single-stage pump. Part 1 (above)
enclosed type impeller, Part 2 (lower left) open type impeller. (Cour-
tesy Peerless Pump Div. FMC Corp.)

(text continuedfrom page 161) 2. Semi-enclosed-used for general purpose applica-
Basic Parts of a Centrifugal Pump tions, has open vane tips at entrance to break up sus-
pended particles and prevent clogging.
Table 3-3 is a quick reference as to the function of the 3. Open-used for low heads, suspended solids appli-
basic parts. cations, very small flows.

Small radial vanes are usually provided on back shroud
Impellers
or plate of impeller to reduce the pressure on the stuffing
box, and prevent suspended solids from entering the back
The three common types of impellers that impart the
main energy to the liquid for process applications are (see side and possibly causing clogging.
Figure 3-15) : The working or pumping vanes are backward in form
relative to the impeller rotation.
1. Fully enclosed-used for high head, high pressure These impellers are available in nearly any material of
applications. construction as well as rubber, rubber-lined, glass-lined,