Flowserve TB-MAG INNOMAG - Manual (Page 23)

INNOMAG® TB- MAG™ ASME and ISO SEALLESS ENGLISH 26999988 06-14
Page 23 of 44
Alarm and trip values for installed
pumps should be based on the actual
measurements taken on the pump in the fully
commissioned as new condition. Measuring
vibration at regular intervals will then show any
deterioration in pump or system operating
conditions.
Vibration velocity –
unfiltered
Horizontal pumps
 15 kW
Horizontal pumps
> 15 kW
mm/s (in./sec) r.m.s.
Normal N  3.0 (0.12)  4.5 (0.18)
Alarm N x 1.25  3.8 (0.15)  5.6 (0.22)
Shutdown trip N x 2.0 
6.0 (0.24)

9.0 (0.35)
Where a unit is utilized in a vertical shaft
configuration with a duck-foot bend onto the pump
suction, the following apply:
Vibration velocity
– unfiltered
Vertical configurations
mm/s (in./sec) r.m.s.
Normal N  7.1 (0.28)
Alarm N x 1.25  9.0 (0.35)
Shutdown trip N x 2.0 
14.2 (0.56)
5.5.2 Stop/start frequency
Pump sets are normally suitable for the number of
equally spaced stop/starts per hour shown in the
table below. Check capability of the driver and
control/starting system before commissioning.
Motor rating kW (hp)
Maximum stop/starts
per hour
Up to 15 (20) 15
Between 15 (20) and 90 (120) 10
Above 90 (120) 6
Where duty and standby pumps are installed it is
recommended that they are run alternately every
week.
5.6 Stopping and shutdown
a) Close the discharge valve, but
ensure that the pump runs in this condition for
no more than a few seconds.
b) Stop the pump.
c) Switch off flushing and/or cooling/heating liquid
supplies at a time appropriate to the process.
d) For prolonged shut-downs and
especially when ambient temperatures are likely
to drop below freezing point, the pump and any
cooling and flushing arrangements must be
drained or otherwise protected.
5.7 Hydraulic, mechanical and
electrical duty
This product has been supplied to meet the
performance specifications of your purchase order,
however it is understood that during the life of the
product these may change. The following notes may
help the user decide how to evaluate the implications
of any change. If in doubt contact your nearest
Flowserve office.
5.7.1 Specific gravity (SG)
Pump capacity and total head in metres (feet) do
not change with SG, however pressure displayed
on a pressure gauge is directly proportional to SG.
Power consumed is also directly proportional to
SG. It is therefore important to check that any
change in SG will not overload the pump driver or
over-pressurize the pump.
5.7.2 Viscosity
For a given flow rate the total head reduces with
increased viscosity and increases with reduced
viscosity. Also for a given flow rate the power
absorbed increases with increased viscosity, and
reduces with reduced viscosity. It is important that
checks are made with your nearest Flowserve
office if changes in viscosity are planned.
5.7.3 Pump speed
Changing pump speed effects flow, total head, power
consumed, NPSH
R
, noise, and vibration. Flow varies
in direct proportion to pump speed, head varies as
speed ratio squared and power varies as speed ratio
cubed. The new duty, however, will also be
dependent on the system curve. If increasing the
speed, it is important therefore to ensure the
maximum pump working pressure is not exceeded,
the driver is not overloaded, NPSH
A
> NPSH
R
, and
that noise and vibration are within local requirements
and regulations.
5.7.4 Net positive suction head (NPSH
A
)
NPSH available (NPSH
A
) is a measure of the head
available in the pumped liquid, above its vapour
pressure, at the pump suction branch.
NPSH required (NPSH
R
) is a measure of the head
required in the pumped liquid, above its vapor
pressure, to prevent the pump from cavitating. It is
important that NPSH
A
> NPSH
R
. The margin
between NPSH
A
> NPSH
R
should be as large as
possible.
If any change in NPSH
A
is proposed, ensure these
margins are not significantly eroded. Refer to the