The flush pressures should be 10% higher than the pressure inside the pump. For end suction pumps
this will also include pump discharge pressure. Product flush pressure to the inner lantern ring may be
slightly less than the water flush pressure to ensure flow toward the inside of the pump.
The flush flow depends on the application, the more heat generated the higher the flows must be to ef-
fectively remove the heat. The table below can be used as a starting point for initial setting: The table
below represents the flow required with one flush line, for a dual flush arrangement the flow can be divid-
ed up equally.
Table 10: Flush Flow
Sleeve dia. (inches)
Flush Flow (gpm)
2
.05
3
.15
4
.30
6
1.3
8
2.5
10
5.0
12
8.0
The stuffing box is furnished with (2) inlet and (2) outlet ports for piping of the flush liquid. The inlets are
chosen based on shaft rotation direction so the flush flow travels the longer route to the outlet ports (see
Inlet and Outlet Ports
figure). The outlet ports may be plugged, but for improved cooling of the sealing
elements, outlet pipes are installed to allow more flow through the stuffing box. With this setup flush flows
are regulated by a valve on the outlet line rather than by throttling the flow on the inlet line.
Figure 28: Inlet and Outlet Ports
Installation
1.
Be sure the stuffing box and shaft sleeve (126) are clean and free of grit.
2.
A PTFE restrictor bushing is used in the bottom of the box and is installed similar to packing (see
Packing Rings
figure). With the restrictor bushing wrapped around the shaft, push it squarely into
the stuffing box until it bottoms out. Be sure the ends have not separated and that it sits square in
the bottom of the box. Note, where the cut is positioned.
3.
Form packing over a mandrel of same shaft diameter and carefully cut packing to length. Discard
rings cut too short.
4.
Pre-form each ring by coiling 1-1/2 turns.
5.
To install packing rings, do not pull straight. Expand the coil as a coil spring, see
Packing Rings
figure, for the correct and incorrect method of installing packing.
9.1 Special Packing Arrangement
Model AF (42"/1200mm/54"/60"/66") LM/LMR Bearings Installation, Operation, and Maintenance Manual
77
