Statistics do not bode well for the occasional industrial pump purchaser. The large water utilities, with tens of thousands of pumps handling municipal wastes, are able to select the right pump via ready access to performance records and fluid technology expertise. Derek Jackson, Hidrostal, offers a few pointers for the industrial user.
The operators of industrial plants throughout the world have to cope with a wide variety of fluid transfer and waste treatment processes, of which the most common, and troublesome, component is often the pumps. The simple fact is that there are a very large number of pump manufacturers, each offering a bewildering array of types and sizes, which almost always ensures that the best pump for the job will not make it to the site. The replacement of an unsuitable pump is also likely to be less than ideal for the same reasons.
As the range of liquids is vast, the materials from which the parts in contact
with the pumped liquid must be equally varied. Experienced pump suppliers must
be able to supply casings, impellers, bearings and other parts in materials
suitable for dealing with the most abrasive and aggressive liquids.
From a core business viewpoint, the most ignored feature of pump selection
damage to the pumped liquid. The high turbulence within pumps, and in the downstream
tail effect within the pipe, can impart significant damage to molecular structures. Fluids as diverse as
paints, yoghurts and bio-cultures such as activated sludge, all require the
Absolve the supplier
Physical damage is equally important. The undamaged transfer of fruit and vegetables
is a frequent duty, as is the transfer of live fish. High speed, centrifugal
pumps are not well suited for such damage-free situations, even when using the
famous non-clog variants which pass a 75mm sphere.
So how much do you need to pump, now and next year? With damage issues sorted,
the actual sizing of the pump usually occupies little time as the end user is
expected to supply the figure. No matter whether it is litres/second, gallons/
minute, or even tons (or tonnes) per day, all absolve the pump supplier, and
that is that.
Not too sure of the flow, now or in the future? Then what is needed is an expensive
variable speed unit. Or – a pump output which matches inflow, whilst using a
fixed-speed motor. Hidrostal’s Prerostal technology provides a variable output
without the need for a variable speed drive. The flow to each pump enters a
compact sump and the basin geometry produces a rotational speed which is proportional
to inflow. The output of the fixed speed pump is directly related to rotational
speed and, consequently, output matches inflow. No pump downtime means uninterrupted
production. The breakdown of a manufacturing process pump, or pumps within the
plant treating production waste, is not just a pain for the maintenance department;
production can cease. This is every manager’s nightmare, particularly where
continuous processes are involved. Real costs pile up and the situation is often
compounded when it is found that no spares are available for that immobile pump.
Pleasure it most definitely is not. Production pleasure is influencing the initial
selection and never experiencing problems thereafter. This is possible, as major
multi-national companies are well aware.
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