Operation of the pump after failure of the consumable peristaltic tube may result in a flow
of chemicals to the inside of the pumphead. Some aggressive chemicals are not compatible
with the pumphead materials. These aggressive chemicals will react to the materials
internal to the pumphead and may cause leaks.
In the worst case, chemicals could leak out from the pumphead and attack the drive shaft
and lip seal, damaging the seal integrity. Damage to the seal could cause aggressive
chemicals to enter the pump housing and react with the components internal to the pump
housing. The reaction may produce explosive gases inside the pump housing.
Danger of damage to pump and possible risk of explosion, if process
chemical has entered the pump housing.
The pump housing contains aluminium components which can react
with some chemicals to produce explosive gas.
In the event of tube failure the pump should be isolated from both
electrical and hydraulic supplies. Immediately remove the ReNu
pumphead and check the drive shaft for signs of chemical residue. If
chemical is found contact your local Watson-Marlow representative. Do
not connect the pump to mains power until you have consulted with
your local Watson-Marlow representative!
For instruction on pumphead replacement see "Pumphead
Replacement (qdos 30)" on page 131 or "Pumphead Replacement
(qdos 20, 60, 120 and CWT)" on page 139.
To prevent dosing liquid entering the pump housing follow the
recommended actions below.
To prevent damage to the pump and pumphead due to failure of the consumable peristaltic
tube:
•
change the pumphead shortly after failure or when recommended to do so by the
pumps pumphead management system
•
do not use the ‘ignore’ function as a long term solution to a failed pumphead.
Approved use of the Ignore function: In order to de-pressurise and drain down the
system and to allow for the safe disposal of the pumphead, the ignore function can
be used to operate the pump prior to changing the pumphead. This is the
ONLY
approved use of the IGNORE function. Option removed in later models.
•
install a non return valve in the discharge line close to the pump when pumping
against a positive pressure. This will prevent a constant stream of chemical flowing
back into the pumphead after failure. Flow area of at least 50 mm² is recommended
for the valve. Do not go below 50 mm² flow area / 8 mm inner bore on the outlet side
for water-like fluids.
•
isolate the main power supply to the pump. Isolation devices can be controlled using
the leak detection alarm signal
•
do not disable the pump leak detection system
•
change the pumphead prior to failure when pumping very aggressive chemicals that
are not compatible with the pumphead materials. There are volume and hours
counters in the product to provide indication of consumable life.
•
isolate the pump (from pressure) when filling chemical storage tanks
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