Wilo VT - Page 31

Installation and operating instructions WILO Mather and Platt – VT pumps 31
8.10 Discharge line (Fig: 5&8, Pg. No. 6&7)
CAUTION! Damage to the pump
Pump can rotate in reverse direction in the absence of a
non-return valve. A back flow can seriously damage the
bearings, mechanical seal and other pump internals.
Discharge piping should be anchored, supported and
restrained near the pump to avoid application of forces and
moments in excess of those permitted by the pump
manufacturer.
If it is necessary to use an expansion joint, it is
recommended that a pipe anchor to be located between it
and pump. Note that an anchor provides axial restraint,
whereas a pipe support or guide does not.
8.11 Stuffing box packing (Fig. 12 Pg. No. 10)
CAUTION! Risk of quick wear or leakages
Packing should be handled with care and it should not be
allowed to pick up the dust or abrasive matter by coming
into contact with floors or dirty benches. It is bad practice
to hammer packing to facilitate the insertion.
Pumps are dispatched from our works with the stuffing
boxes unpacked; otherwise packing will be aged. The
packing is packed with greaseproof paper and dispatched
with the pump. The softest possible packing i.e. plaited
cotton impregnated with oil and colloidal graphite is
recommended for most duties. Required number of and
lengths of packing should be cut off so that each length will
pass once round the shaft sleeve line and meet to end. The
ends of packing must be cut at 45°.
After cleaning the stuffing box and shaft sleeves the
packing should be inserted into the stuffing box. Each ring
should be pushed into position individually using the glands
joint of each ring must be positioned 180˚ from joints of its
neighbor. A logging ring included in the arrangement;
should be inserted into the stuffing box at the appropriate
time during the packing sequence so that it is aligned with
the cooling water connection. The gland should now be
fitted square with the motor stool and the nut should be
screwed up to little more than finger tightness.
8 .12 Mechanical seal
CAUTION! Damage to the pump
Never start the pump without liquid inside otherwise the
mechanical seal will be damaged instantaneously.
No real operation is required during the setup of the pump.
Only filling and venting the pump are mandatory before
switching on the main
8.13 Pressure gauge connections
CAUTION! Risk of leakage of the fluid!
Never connect a pressure gauge onto the pump when the
system is under pressure.
Pressure gauge connections are available on motor stool
close to the delivery flange. Then pressure gauge can be
connected on discharge side.
8.14 Air release valves
For vertical pumps an automatic air release and vacuum
release valve is recommended. The valve should be located
on pump discharge nozzle. This valve prevents a large volume
of air being compressed, and then setting up a severe shock
wave when suddenly released with potential for serious
equipment damage. The air release valve also prevents air
from entering the pressurized system.