Installation
TT Twin-Screw Pump -
Installation, Operation & Maintenance Manual
31
Ductile Iron
6.5 x 10
-6
(11.7 x 10
-6
)
Carbon Steel
6.5 x 10
-6
(11.7 x 10
-6
)
Austenitic Stainless Steel
8.9 x 10
-6
(16 x 10
-6
)
Temperature rise
Δt
= operating temperature
– ambient temperature. The foot to shaft
centerline distance is the distance from the bottom of the pump and driver feet to the center of
their respective shafts. This information may be found on the GA or outline drawing.
Worked Example (US units)
Ambient Temperature -
80
o
F
Operating Temperature -
224
o
F (driver, taken from the max. temperature for Class B)
Operating Temperature -
100
o
F (pump)
Material of Construction -
Cast Austenitic Stainless Steel (pump)
Material of Construction -
Cast Steel (driver)
CL Height Pump -
13”
CL Height Driver -
11”
•
Change at pump shaft due to temperature rise = 8.9 x10
-6
x (100-
80) x 13” = 0.002”
•
Change at driver shaft due to temperature rise = 6.5 x10
-6
x (224-
80) x 11” = 0.010”
•
Difference = 0.002
” – 0.010” = -0.008”
In this example, the pump should be set 0.008
” higher than the driver to allow for proper
alignment at operating temperatures.
The above formula is an approximation and does not account for the influences of piping,
casing geometry and hot and cold spots created by circulation of air. Hence while it is important
to utilize the above method for cold alignment, final alignment should still be checked in the hot
condition.
The following steps should be taken to ensure proper coupling alignment during operation.
1. Calculate thermal growth and compensate accordingly when aligning the coupling.
2. Check coupling alignment while both pump and driver are hot to ensure alignment is correct
for the operating conditions.
Summary of Contents for HOUTTUIN TT Twin-Screw
Page 1: ...TT Twin Screw Pump Installation Operation Maintenance...
Page 2: ......
