7.4 Dry running
Dry running is a running condition of the pump when no fluid is flowing through the hose. Bredel
hose pumps allow dry running for limited periods.
Dry running imposes an additional thermal load on the hose, because a part of the internal heat
associated with repetitive hose compression is normally removed by the process fluid. So dry running
increases the wear on the hose.
The thermal load depends on the running speed of the pump, as well as the rotor type (low pressure
or medium pressure).
To minimise the extra wear, it is advisable to minimise dry running periods to less than a minute at a
time.
7.5 Hose failure
Cause of a hose failure
The hose in a peristaltic pump has to withstand many load cycles of compression. The repetitive
stress cycles will cause the hose to deteriorate and eventually fail.
Result of a hose failure
A hose failure will result in direct contact between the pumped fluid and the pump lubricant, the
internal parts, and the dynamic seal.
Consequences of a hose failure
In general, this will not cause a hazardous situation because the Bredel Genuine Hose Lubricant is
harmless (approved by the United States Food and Drug Administration). However, there is an
exception in case of pumping a strong oxidiser or a strong acid.
See also
Refer to "Lubricant table pump" on page 83 for the required quantity and NSF registration.
38 m-bredel-25-32-en-05
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