GRISWOLD PUMP COMPANY Installation Page 11
Installation, Operation and Maintenance Manual
Griswold Model 811
Griswold Pump Company Installation Page 13
In any case, disregard the coupling manufacturer’s published misalignment limits, as these
will impose unacceptable loads on the pump and motor shafts and bearings.
Alignment is done with the coupling spacer removed.
Since any misalignment will impose loads on the pump and driver shafts, the objective is to
minimize any misalignment in order to protect the pump and driver and minimize any tendency
for vibration. Suggested misalignment limits are:
Pump Frame Group Max. Parallel Max. Angular
S, M, L 0.005" 0.005"
XL 0.010" 0.010"
For optimum performance and Mean Time Between Pump Maintenance (MTBPM), use
alignment limits half of those shown above.
Alignment must be done at several different times:
1. Prior to grouting baseplate during installation
2. After grouting baseplate and tightening anchor bolts
3. After attaching suction and discharge piping prior to initial operation
4. Hot alignment after equipment temperatures have stabilized
5. After pump maintenance if back pull-out assemblies are removed
Since the Model 811 pump is foot-mounted, its shaft centerline will rise when handling pumpage
at elevated temperatures. Similarly, the motor shaft centerline will rise as it reaches its operating
temperature. Therefore, we will often purposely mis-align shafts vertically during cold
alignment to allow for thermal growth, thus bringing the shafts into alignment at operating
temperature. This is shown in Table 2 on Page 15.
The Griswold Model 811 is an ANSI B73.1 Process Pump and is, therefore, furnished with a
spacer coupling to enable removal of the back pull-out assembly without disturbing the casing or
moving the motor driver.
The most simple alignment check is with a straight edge and calipers or inside micrometer. This
method is the least accurate, but it will serve if a dial indicator or laser is not available.
Table 1
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