Flowserve MNV - Manual (Page 14)

MNV & MNZ USER INSTRUCTIONS ENGLISH 71569188 11/04
Page 14 of 47
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3.2 Name nomenclature
The pump size will be engraved on the nameplate
typically as below:
24-MNV/MNZ-47
Nominal discharge branch size.
Type/Configuration – see sec. 3.0.
Nominal impeller diameter.
(Size in inches only)
The typical nomenclature above is the general guide
to the MNV/MNZ configuration description. Identify
the actual pump size and serial number from the
pump nameplate. Check that this agrees with the
applicable certification provided.
3.3 Design of major parts
3.3.1 Pump casing & stuffing box head
The pump casing with its integrally cast discharge
nozzle is of the volute type. It is machined to provide
a rabbet fit for the stuffing box head and suction
head. The heads are removable and are bolted to
and centered in the casing. The casing and suction
head are each provided with one hand hole for
inspection and cleaning of the pump without
dismantling. The pump has its main casing gasket
axial to the shaft allowing maintenance to the rotating
element by separating the impeller assembly from
the casing. Suction and discharge branches remain
undisturbed
3.3.2 Impeller and wearing rings
The impeller is a solids handling type capable of
passing trash and solids of limited size. The impeller
hub is keyed to the shaft and held in position by an
impeller nut which is set screwed to the impeller to
prevent its backing off. A pair of replaceable wearing
rings (optional) between the rotating impeller and the
stationary suction head are provided for impeller
wear resistance.
3.3.2.1 Impeller and wearing ring arrangement
IMPELLER
IMPELLER
WEARING RING
SUCTION HEAD
WEARING RING
SUCTION HEAD
3.3.3 Shaft and shaft sleeve
The pump shaft is sized to transmit the rated loads
encountered with liberal safety factors, and is
accurately machined over its full length. Generous
fillets are used to minimize stress concentrations. It
is protected from wear at the stuffing box by a
removable shaft sleeve.
3.3.4 Pump bearings and lubrication
MNV & MNZ pumps are equipped with anti-friction
bearings of the tapered roller type. The line and
thrust bearings are arranged in opposed mounting
and can be furnished with grease as standard and
custom built oil lubricated pumps.
3.3.5 Bearing housing
Bearings are mounted in a removable cast iron
bearing frame. The frame casting offers solid support
and location to the bearings and two grease nipples
enable grease lubricated bearings to be replenished
between major service intervals.
3.3.6 Stuffing box housing
The stuffing box housing cast integrally with the back
head and has designed number of sealing options.
For applications requiring Mechanical Seals refer to
the Mechanical Seal Manufacturer's instructions.
Packing within the pump stuffing box seals the pump
against leakage along the shaft at the point where it
passes through the stuffing box. It should be packed
with rings of braided, non-asbestos packing and a
seal cage. It is equipped with a split removable
packing gland.