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Cheap filter pumps not always the most cost effective? SERFILCO's Stephen Lorimer discusses the benefits of quality over cost.

If you want cheap filter pumps SERFILCO can compete on price if that is really only what you want. But there is much more on offer from the filtration specialists to the metal finishing industry. We would like to ask you to at least consider the wider picture.

Plant engineers are well aware that the initial capital-cost of a filter pump system pales into insignificance when considering total operating costs. Firstly, if a pump's design is inherently inefficient and needs a larger kW motor in the first place it is a complete waste of energy. Secondly, if the pump requires a lot of maintenance and results in downtime, then these high ongoing costs stay with you till the bitter end. Here is a break down of the relative costs:

Whole Life Costs:

Motor Power--87%, Maintenance--8% and Initial Cost--ONLY 5%

The Pyramid has been inverted, from the most often lowest price focus, being the least % factor above. Maintenance or maintenance-free should be given much closer attention.

Today two or even three year warranties with full service and maintenance packages are an increasing stipulation when choosing the most cost effective equipment. So the reliability of equipment now on offer has to be up to this high standard, and is generally of a much more robust and leak free construction.

For example, seal-less vertical pumps are capable of continuous run-dry operation without failure and even the new SERFILCO's Own Design Sealless Magnetic Coupled Pumps are capable of limited run dry for periods of up to 1 hour.


20 or more years ago it was very much the era of plate and paper filters, where 1 or 2 tank turnovers per hour were the norm. Times have moved on and turnovers have moved on up, but there are many examples today where there are installations experiencing roughness rejects even with clean flow rates around 3 or 4 turnovers. Maximising tank turnover rates is the SERFILCO proven way of achieving the ultimate goal of zero rejects. This has been one of our mantras for many years, and the uptake has been steadily increasing.


Today with high flow performance and highly efficient dirt holding capacities, these much higher goals are more easily achieved, at not that high a cost. As always filter systems are measured at initial clean flow and it is important to maintain a high flow rate right up till the moment when cartridges need changing.

Unfortunately we are still seeing the promotion of filter pump performance by some as the pump max flow rate, rather than the more realistic system flow rate. Which in most cases is a slightly reduced figure, therefore when attempting to compare like for like this can be highly misleading. The all important tank turnover rate actually achieved may well be much below that advertised. Importantly also is the filter pumps pressure capability. It is this hidden factor that enables the filter pumps max flow rate to be maintained for much longer periods.

Also, attempts have been made to improve filtration efficiency by simple changing to a more efficient type of filter cartridge. Often the full cycle of trials with varying types have been tested and still roughness problems persist. Only when an additional back up filter is introduced or a bigger flow pump has been fitted to increase tank turnovers to in excess of 6 times (and even 10+ tank turnovers in critical applications) has the problem been eliminated.

Increasing tank turnovers together with fitting more efficient absolute rated filter cartridges is then the ultimate combination to achieve perfection.


Airless agitation is a SERFILCO innovation which is now enjoying wide spread acclaim within the metal finishing industry. It operates on a simple venturi principle, whereby for every litre pumped in--agitation flow is up to 5 times greater. A multiplier effect is achieved to provide significant turbulence in the directional plume exiting from the trumpet like nozzles.

The major benefits that can be realised with short payback guaranteed, include:

* Virtual elimination of fumes emissions

* More even distribution

* Less chemical additions

* Savings on heating

* Faster plating rates


All filter systems don't have to be conventional floor mounted with hoses over the side or even piped through the side wall of the process tank itself. Vertical pumps need not always be mounted in-tank, like sump pumps. Often the up take has been unjustifiably restricted due to concerns such as:- limited space inside the tank--obstructions such as transporter track with safety guards and even motors drawing in hot corrosive fumes; These issues can be overcome by mounting vertical pumps outside the tank.


Powdered carbon is a messy and difficult way of effecting a proper carbon treatment. It may temporarily remove the organic contamination, but then of course there will be another build up over a period of time until another treatment is required.

This represents the classic saw-tooth graph, whereby a cycle of bath quality changes rapidly from good to bad and repeated again. Bulk granular carbon contained in a separate canister alongside the cartridge filter chamber allows by-pass of pre-filtered solution to flow slowly through the honeycomb structure. It is totally controllable and can be done continuously or intermittently depending entirely upon the level of treatment required.
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Title Annotation:advertisement feature
Author:Lorimer, Serfilco's Stephen
Article Type:Advertisement
Date:Nov 1, 2004
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