Pump action

The humble pump or valve is being transformed into a highly developed solution for specific technical challenges. Colin Carter reports

Pumps and valves are the unglamorous but very necessary core components of many small and large-scale installations where materials need to be moved round and regulated as part of a process.

Pumps, in the main, move materials from A to B, usually by pressure, whereas valves (generally speaking) regulate the rate of flow of materials. Other than mainline process valves, there are also pressure relief and burst valves, used for safety.

With great growth opportunities in the developing markets of eastern Europe and the far east there is much evidence that this is having a real effect on sales of plant components such as pumps and valves. Indeed, a recent report from Frost and Sullivan on the European centrifugal pump market estimated that it will grow by around 20 per cent by 2013, driven by additional countries joining the EU.

Many new products coming to market are highly-developed specialist offerings. For example, recently-introduced pumps from Verder and 3m are designed to provide safe transport of materials. Verder’s Verderflex seal-less peristaltic pumps are claimed to offer degradation resistance — especially to petroleum-based products — while 3M‘s Magnetic drive centrifugal pumps are designed for aggressive fluids such as acids and explosive chemicals.

Chemical resistance is also the selling point for recently-introduced stainless steel valves from Legris, while ‘valveless pumping’ incorporated in new products from FMI is aimed at applications where aggressive chemicals are processed.

Hygiene and cleanliness is another selling point. Recent examples include hygienic stainless steel sample valves from Axium Process and Samson Controls’ type 3347 control valve, and there are many others on the market.

Pumps and valves can also be used for dosing applications — where pre-determined amounts of product are delivered. Examples include the Grundfos KM 250 and KM 280 series pumps aimed at the petrochemicals sector and Sealant Equipment and Engineering’s Model 2600-060 valve aimed at regulating the flow of medium to high-viscosity materials.

Considering the diversity of applications where pumps and valves are used it’s easy to see that they continue to be the best way of moving and regulating materials in a wide range of industries.

The entertainment industry has also used them on film sets. On one of the recent Pirates of the Caribbean films, for example, a hydraulic system was employed to move a floating motion base (holding full-size replica sailing ships) and to replicate a realistic wave motion for filming.

A system developed by Parker Hannifin used hydraulic cylinders to move the set and was controlled by an array of Parker pumps and accumulators operating through a series of hydraulic valves, which enabled each ship to be rocked along three axes for realistic motion. The pumps and throttle valves were part of a system operating at flow rates approaching 4,000 litres/min.

On a different note, the beer some of us enjoy in pubs is delivered to the bar via a tap, or valve. but valves and pumps are also employed extensively in the manufacture of beers. At the Coors’ Burton Brewery a set of Honeywell 15 reduced pressure zone (RPZ ) valves ensure water can’t discharge from the process side back into the mains system in the event of the mains pressure falling. These valves avoid problems of contamination by legionella inherent in other solutions and ensure the plant is both as environmentally friendly as possible and unlikely to contaminate local waterways.

Also in the brewing industry, filtering of beers using the abrasive filtering body diatomite (or diatomaceous earth) is common. At the Paulaner Brewery in Munich, Germany, which is claimed to be the largest in the city, filtration of the beer is effected by moving this abrasive diatomite and beer mixture around using Larox Flowsys peristaltic pumps.

These move the mixture by a squeezing motion much in the same way the human intestine works, and are the most reliable solution where abrasive materials such as diatomite would cause rapid wear in a vane-driven pump.

At the brewery the process requires filtering for around seven to eight minutes with material flow rates of between 1.5 and 7 cubic metres/hr. As an example of the pumps’ reliability, some have been in continuous use for some two years, keeping the beer pure without needing downtime for pump replacement.

Another advantage of peristaltic pumps is that only the hose is in contact with the material being pumped, making clean operation a simple process. Watson-Marlow Bredel’s 700 series forms the heart of Cleveland Biotech’s ‘Baccelarator’ effluent treatment system.

As a result the system is now claimed to be able to able to run continuously with no contamination and no downtime lost — a big bonus over batch systems where bacterial growth and efficacy is exponential.

In another process, Spirax Sarco steam control valves are employed in the processing of sugar at Ragus Sugars’ Slough refinery. The valves are used as part of a newly-automated process to control the steam used to dissolve sugar batches in pans and water in the cooling as the final stage of the process.

The company claims installing the system has meant benefits in terms of improved control and more consistent product quality .

Greater automation also led to the installation by AJG Waters Equipment of a set of pinch valves at an industrial wastewater processing unit forming part of a steel plant. The company installed RF Tek pinch valves to control an automated sand filtration system that had to cope with a range of solids, chemicals and minerals in the water and were chosen for their low installation and maintenance costs.

In another application where careful handling of materials is required, commercial explosives manufacturer Orica Mining Services has specified Netzsch BY progressive cavity pumps to remove ammonium nitrate emulsion and oil as part of its batch process at the company’s Wigan and Glensanda plants.

These compress the fluids in stages and are capable of safely pumping up to 10 cubic metres of emulsion at pressures of up to 18bar safely, which is obviously a key requirement in this process.

A final demonstration of the ubiquity of pumps and valves is their use in engines — but not just in cars. When diesel and natural gas engine manufacturer Perkins decided to upgrade its 4012 engine from a bi-turbo charger to a quad-turbo charger it used a custom-developed air intake shut-off valve from Amot Controls to reduce the run-away of hydrocarbon vapours — thus improving efficiency.

So although pumps and valves may be unglamorous on face value, there are plenty of cases where they are key components in plants and processes around the world.

In fact, it’s unlikely that anything we use or consume (with the exception of the most unprocessed foods) has not been subjected to some action by pumping and/or valve regulation. Something to consider next time you order a pint in a pub.