Preventative maintenance
AODD pumps are very reliable since
they need only a few moving parts and components which will wear. They compare
very favourably with pumps that have close-fitting sliding or rotating
mechanisms, where the passage of abrasive slurries, for instance, can cause
excessive wear to the moving parts of the pump.
This can cause significant
downtime and repair costs. These problems don't arise with AODD pumps since
large internal volumes and flow through prevent clogging, with the dimensions
of solid particles which will be pumped associated with the pump size.
Key
factors to think about for preventative maintenance are:
• Diaphragm lifetime
• Compressed air quality
• Flushing of pumps after use.
The diaphragm may be a dynamic
seal that converts the pneumatic pressure on one side to fluid pressure on
the opposite (the material to be pumped). Although the differential atmospheric
pressure across the diaphragm and corresponding internal stresses are lower as
compared with similar stresses in mechanically driven diaphragm pumps that use
the diaphragm to get pressure, the AODD
pump diaphragms must flex through many cycles to try to their work.
All diaphragm types will have a
finite flex life and therefore the use of a pump stroke counter allows the flex
life to be monitored as a neighbourhood of preventative maintenance good
practice. Elastomer diaphragms are typically guaranteed for a flex lifetime of
approximately 20 million cycles and PTFE-based diaphragms for around 12 million
cycles, but some PTFE diaphragms are known to last 30 million cycles.
Although the pumps can dry out
with no damage, diaphragm flex life is often reduced if the pump runs dry for
extended periods of your time.
Careful consideration should tend
to the compressed gas supply used. Air is drawn into the compressor from the
atmosphere and can contain some moisture. This air expands quickly inside the
pump with the result that the water can freeze. The ice formed on the moving
parts of the air valve can cause them to stay, causing the pump to stall.
Although air valves are designed to minimize this possibility, its good
practice to form sure that the air is dried before it enters the compressor.
In addition, engineers frequently
lubricate a compressed gas line. This practice should be avoided thanks to the
potential to contaminate the pumped fluid. There’s a further environmental
benefit to using oil-free compressed gas since no oil mist is vented into the
atmosphere also because of the incontrovertible fact that there also are no costs
related to oil consumption or lubrication.
Since AODD pumps are often used
for pumping such a good range of fluids, consideration should tend to flush the
pump through after use, especially for fluids like concrete, or glue, which can
solidify within the pump if not removed after pumping is complete. Once a substance has solidified within the pump it must be completely stripped down
for refurbishment.
Maintenance
and repair strategies
Since AODD pumps are utilized in
such a good range of applications and industries, individual users will have
their own approach to maintenance and repair strategies. Uses can vary from the
occasional emptying of a container using the pump as a scavenger, to 24/7 use
on a critical assembly line. Although AODD pumps are easily dismantled for
maintenance or diaphragm replacement, not all users will want to hold out their
own maintenance or repair – AODD
Pump Suppliers, they'll like better to return the pump to the supplier
for refurbishment.
For pumps getting used in critical
24/7 applications, having a spare pump which will be swapped within the event
of a pump failure is important. This
might literally be a spare, or one getting used during a different application
which will be used at short notice.
The most comprehensive approach
would be a three-pump strategy – one in use, and two spares. Within the event of a failure, the damaged the pump is replaced by a spare and returned for repair, still leaving a spare on-site while the repair is administered.
For companies who want to hold out
their own repairs, an ‘airside’ repair kit is often provided which contains
components like ball valves, diaphragm valve seats etc. that are in touch with
the pumped fluid, and a ‘dry side’ kit which contains items like a pump shaft, O-rings,
gaskets etc. for several years now, companies have sought to lower their
overheads by holding less stock, numerous end users could also be reluctant to
carry spares for his or her pumps.
Most AODD
Pump Manufacturers provide five-year warranty which is a very good thing for
a user. Some independent manufacturers will offer a 5 year no quibble guarantee
which avoids this lengthy process.
Finally, the value of repairs and
refurbishment should be considered. In today’s ‘consumable society’, it's often
cheaper to easily buy new instead of buying a repair. Within the world of AODD
pumps, the rule of thumb is that pumps but a 1/2” are generally not worth
repairing.
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