Xylem IM191 R03 Marlow Series Prime Line Self-Priming Centrifugal Pumps - Manual (Page 5)

5
Figure 5 Figure 6
H min.
D D
H min.
D D
1.5D
min.
3.0D
min.
H min.
D min.
2
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
H = Min. Submergence in feet
H
1 2 3 4 5 6 7 8 9 10111213141516 V
V = Velocity in feet per second
= GPM x 0.321
Area
GPM x 0.4085
D 2
Figure 3 Figure 4
FRAME-MOUNTED UNITS ONLY
• Alignment MUST be checked prior to running. See Figure 2.
Figure 2
• Tighten all hold-down bolts before checking alignment.
• If realignment is necessary, always move the motor. Shim
as required.
• Parallel misalignment, shafts with axis parallel but not
concentric. Place dial indicator on one hub and rotate this
hub 360° while taking readings on the outside diameter of
the other hub. Parallel alignment is achieved when reading is
0.010" (0.254 mm) TIR, or less.
• Angular misalignment, shaft with axis concentric but not
parallel. Place dial indicator on one hub and rotate this hub
360° while taking readings on the face of the other hub.
Angular alignment is achieved when reading is 0.020"
(0.508 mm) TIR, or less.
• Final alignment is achieved when parallel and angular re-
quirements are satisfied with motor hold-down bolts tight.
NOTICE: ALWAYS RECHECK BOTH ALIGNMENTS
AFTER MAKING ANY MECHANICAL
ADJUSTMENTS.
Piping
• Piping should be no smaller than pump’s discharge and
suction connections and kept as short as possible, avoiding
unnecessary fittings to minimize friction losses.
• All piping MUST be independently supported and MUST
NOT place any piping loads on the pump
NOTICE: DO NOT FORCE PIPING INTO PLACE
AT PUMP SUCTION AND DISCHARGE
CONNECTIONS.
• All pipe joints MUST be airtight.
PIPING – SUCTION
• For suction lifts over 10 ft. (3 m) and liquid temperatures
over 120° F (49° C), consult pump performance curve for
net positive suction head required (NPSH
R
).
• If a pipe size larger than pump suction is required, an ec-
centric pipe reducer, with the straight side up, MUST be
installed at the pump suction.
• If pump is installed below the liquid source, install a gate
valve in the suction for pump inspection and maintenance.
NOTICE: DO NOT USE THE GATE VALVE TO
THROTTLE PUMP. THIS MAY CAUSE LOSS
OF PRIME, EXCESSIVE TEMPERATURES
AND DAMAGE TO PUMP, VOIDING
WARRANTY.
• If the pump is installed above the liquid source, the following
MUST be provided:
• To avoid air pockets, no part of the piping should be above
the pump suction connection.
• Slope the piping upward from liquid source.
• Use a foot valve or check valve ONLY if necessary for
priming or to hold prime during intermittent duty.
• The suction strainer or suction bell MUST be at least
3 times the suction pipe diameter area.
• Insure that the size and minimum submergence over suc-
tion inlet is sufficient to prevent air from entering pump
through a suction vortex. See Figures 3 through 6.
PIPING – DISCHARGE
• Install a check valve suitable to handle the flow, liquids and
to prevent backflow. After the check valve, install an ap-
propriately sized gate valve to be used to regulate the pump
capacity, pump inspection and for maintenance.
• When required, pipe increaser should be installed between
the check valve and the pump discharge.
AIR RELEASE LINE (4E & 6E)
It is essential to allow the air to escape from the discharge
line to atmosphere during the initial priming and re-priming
cycle. In systems with high discharge heads, it may be advisable
to install an air release line between the pump casing and
discharge check valve to aid their venting. The size of the
air release line is selected such that it does not significantly
affect the discharge capacity. You may install an air release line
through the filler plug hole if necessary. However, the preferred
location is in the discharge line – between the pump and the
discharge check valve – as close to the discharge check valve
as possible. We recommend the following line sizes for the
following pumps:
4" pump – ¾" line
6" pump – 1" line
NOTES:
1. This line size may be increased or decreased depending on
application.
2. Direct the air release line back into the sump (not into
the pump suction line). Leave the end of the line open to
atmosphere. Do not submerge into the liquid being
pumped.
3. The air release line may clog, particularly if a shut-off
valve is installed in the line and is closed during operation.
If this condition occurs, either use a larger line or leave the
shut-off valve open during pumping operation. To aid in
maintaining air release lines, fit them with crosses
instead of elbows.
Parallel
Angular