Varisco S.p.A.
Z.I. Nord - Terza Strada, 9 - 35129 PADOVA – ITALY
Tel.+39.049.8294111 Email: [email protected]
Fax+39.049.8076762 Web: www.variscospa.com
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Contact Varisco if you need to change the direction of rotation for pumps that use mechanical seal.
IMPORTANT:
In close coupled versions, it is necessary to check periodically that the shaft grub screw were well
tightened and fits properly in the propeller shaft cavity, especially if the pump is employed in both
directions. To this purpose, see par. 6.1.2.1 of this Manual.
6.2 PIPE ASSEMBLY
6.2.1 IMPORTANT PREMISE
•
Intake and outlet diameters must be adequate, according to viscosity and delivery involved.
•
Accurately clean the pipes before connecting them to the pump.
•
Pipes must be connected to the pump so that no external force may be applied to the pump
itself.
•
Fit adequate compensators between pump and pipes to protect the pump from vibrations
which may damage the pump body.
•
Intake and outlet pipes shall be fitted so that, the pump is not working, there is some fluid
upstream and downstream, in order to ensure that there is always enough fluid in the pump
to provide lubrication at startup.
•
Minimize the air intake in the body pump.
Note: In case fluxed packing glands or fluxed mechanical seals or quenches were used, the feeding
system connections and system tuning must to be carried out
prior to the first startup
.
6.2.2 MAX ALLOWED PRESSURE
Unless otherwise set out in the order confirmation, it is understood that
the maximum pressure
inside the pump body (i.e. with pump turning clockwise) is 6 bar per stage
. The maximum
allowed pressure at delivery is related its features:
•
flange: not exceeding nominal pressure (i.e. PN 16)
•
female thread: not exceeding 25 bar
•
sanitary male thread according to DIN 11851, up to DN 100:
single and double stage pumps: not exceeding 12 bar
multiple stage pumps: not exceeding 25 bar
Other configurations
: In any case not exceeding 6 bar per stage of the stator being used.
6.2.3 USEFUL ADVICE
It is advisable to fit to the pipe union a stub pipe of L length. This will allow the replacement of the
stator without the need of disassembling the pump. The L value is shown in the table below,
according to the size of the pump and the number of stages:
