Watson-Marlow Bredel 265 - Manual (Page 37)

OPERATION
37
7.3 Dry running
Dry running is a running condition of the pump when no
process flow (pumped product) is flowing through the
pump. The Bredel peristaltic pumps are very suitable for
dry running.
Dry running does impose an additional thermal load on
the pump hose, because the internal heat associated
with repetitive hose compression is normally removed
by convection of the process fluid. So dry running
increases the wear of the hose. The magnitude of the
thermal load depends on the size and running speed of
the pump as well as the amount of shims mounted on
the rotor. To minimize the extra wear, it is advised to
minimize the dry running periods.
7.4 Hose failure
The hose in a peristaltic pump has to withstand many
load cycles of considerable magnitude. The repetitive
stress cycles will deteriorate the hose and will
eventually cause hose failure. The hose life strongly
depends on the operating condition, process fluid and
hose material. The end-user should be aware of this
and accept the need for regular hose replacement.
A hose failure will result in direct contact between the
pump lubricant and the pumped medium. In general,
this will not cause a hazardous situation as the Bredel
WARNING
Do not apply dry running in combination
with a flammable process fluid. In case of
doubt, consult your Bredel representative.