56-61 DOSING PUMPS:SPN Master pages 20/11/2009 10:02 Page 57
spnfeature
use the cheapest model or change a overload and permanent damage to the
dosing system without considering what pump, the discharge/feed line should
type of pump will suit the application and not be longer than the pump
what the long-term costs could be. manufacturer recommends for a
Selecting the right dosing pump and particular model.
ensuring all elements are complementary Some types of high capacity
are vital for a smooth and safe dosing dosing pumps can be fairly noisy
operation, so it’s important to choose when running. If the pump is to
carefully and seek the advice of a be installed in a location
respected distributor. adjacent to a ‘quiet area’ such
That’s the message from Gaffey as a sauna suite or in close
Technical Services Ltd, specialists in pool proximity to offices, then a
water treatment and a distributor for quiet running motorised pump
Grundfos-Alldos Ltd, a world giant in (low pulsation) should be used
quality pumps. to preserve the sanity of the
A distributor’s specialist knowledge of a neighbours!
particular application is of great value
when considering dosing systems.
Andrew Gaffey, Director of Gaffey
FOR PAC (FLOCCULANT)
Technical Services Ltd, says: “Not all
chemical dosing pumps are ideal for all of
DOSING
the chemicals commonly used in Considerations should be:
swimming pools. Dosing pumps are used To work efficiently,
in a wide variety of applications across flocculation should be
many different industries, and this is one a continuous process,
of the main reasons that dosing pump so the pump output
manufacturers rely on different should be small enough to
distributors to ‘manage’ pump sales in inject a very small shot of neat PAC into OPPOSITE: The controlled addition of
various specialist areas. They will help the pool circulation line every few
chemicals through the day gives a constant,
regular and controlled operation
them avoid the common pitfalls and seconds. A typical PAC dose rate for a
misconceptions. In today’s highly 25m commercial pool may be only 30- ABOVE: Grundos-Alldos – a world ’giant’ in
competitive leisure industry, the initial 40ml/hr.
quality pumps – available through Gaffey
Technical Services
cost of a product often weighs heaviest in Overdosing of flocculant can result in
a purchasing decision. However, if the excessive filter pressure build-up BELOW: LMI’s Type ‘9’ control is designed so
chosen dosing pump is not designed for (slowing the pool turnover time) and
the clear liquid crystal display provides the
user with operational status. The power
the task, or has been installed incorrectly, frequent and unnecessary
control reduces system shock and extends the
the ongoing costs in service calls, backwashing, leading to unnecessary life of the pump
replacement parts and downtime will expenditure in additional water and
vastly outweigh any initial saving in heating costs. For this reason it is vital
purchase cost. Opting for the cheapest to select a quality pump with very supplier first to get the right model for
product could be a costly mistake.” accurate output control. Diaphragm or your particular requirements. There are a
So what pump specifications are needed peristaltic pumps equipped with lot of pumps on the market, and a lot of
for different dosing products? stepper motors are the best choice for differing requirements, so it’s important to
this application, where the dose rate in make sure you have the right dosing
FOR CALCIUM HYPOCHLORITE
millilitres per hour can usually be system mix. It could save you money in the
directly ‘dialled-in’ to the pump. long run.”
The main points to consider are: To avoid pump maintenance problems, The technical market in the UK boasts a
Pumps should have large bore, robust quality flocculants should be used which number of specialist and respected
suction and discharge valves to are opaque and free of sediment or companies who are all active in supplying
withstand the abrasive, scale suspended solids. the best engineered and best supported
forming solution. equipment.
The pump should be fitted with an auto In short, the things to remember are that Swimming pool water treatment includes
pressure relief valve or electronic it’s important not to have a one-pump- the dosing of flocculants in order to
pressure regulation to protect the pump suits-all approach, think twice about achieve optimal filtration results.
(and operator) from dangerous pressure automatically choosing the cheapest ProMinent Metering Pumps believes the
build-up in the event of an injection pump available, and if in doubt, ask an challenge is that constant and exact dosing
point blockage. expert. of small amounts. ProMinent has worked in
Suction lines should be kept as short as Andrew adds: “It’s important to check the business of metering pumps for more
possible, and, to avoid hydraulic out your requirements with a specialist than 40 years in a leading position and
“THE TECHNICAL MARKET IN THE UK
BOASTS A NUMBER OF SPECIALIST
AND RESPECTED COMPANIES WHO
ARE ALL ACTIVE IN SUPPLYING THE
BEST ENGINEERED AND BEST
SUPPORTED EQUIPMENT”
Visit our website at www.swimmingpoolnews.co.uk >>> December 09 Swimming Pool News 57
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