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News Release from: Pursuit Dynamics | Subject: PDX fluid handling system
Edited by the Engineeringtalk Editorial
Team on 20 June 2003
Fluid handling system streamlines keg
washing
The PDX fluid handling system is maintenance-free, is intrinsically safe, has no moving parts, wear parts or seals, and can operate extremely energy efficiently.
Keg cleanliness is absolutely vital if high-quality draught beer is to be delivered in pubs and clubs Both external washing and internal cleaning need to be conducted thoroughly, involving hot caustic solutions
This article was originally published on Engineeringtalk on 17 Mar 2004 at 8.00am (UK)
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Unfortunately for the brewer, this implies that aggressive chemicals need to be used, and energy consumption for heating and pumping is usually high.
In a traditional external washing system, first the cleaning tanks are filled with water, then caustic chemicals are added and mixed with the water, and finally the resulting caustic solution is heated to a high temperature.
When room-temperature kegs are placed in the cleaning tanks they take thermal energy from the caustic solution, meaning that heat needs to be supplied on an almost continuous basis.
Typical cleaning tanks are filled with water using one pump (or more), then further specialist pumps - designed to withstand aggressive substances - add the caustic chemicals.
Heat is usually supplied via jets that feed steam into the bottom of the tank, thereby adding heat and a small volume of condensate.
Further reading
Multiple roles for fluids handling system
Some in the food industry will view the PDX fluids handling system from Pursuit Dynamics as a pump, whereas others will see it as a heater, cooker, macerator or mixer.
Process pumps, mixes, entrains and heats in one
Soft drinks producers that use artificial sweeteners and thickening agents can now achieve dramatically increased throughput and energy savings thanks to PDX fluid processing technology.
First repeat order for food processing system
Pursuit Dynamics has won the first repeat order for its PDX Sonic food processing system.
All this consumes considerable amounts of energy and requires regular cleaning and maintenance.
Due to the nature of the caustic solution, the life expectancy of the steam jets and pumps can be relatively low.
However, a new technology is now available from Pursuit Dynamics with the potential to replace the water pumps, caustic chemical pumps and steam heating jets, together with any recirculating pumps and mechanical mixing equipment if these would otherwise be required.
Furthermore, the PDX fluid handling system is also maintenance-free, is intrinsically safe, has no moving parts, wear parts or seals, and can operate extremely energy-efficiently.
Because of the elegant simplicity of the concept (the underlying physics are hugely complex), the chance of an unplanned stoppage due to a component failure is virtually nil when compared with the situation where pumps are installed.
The system is extremely compact, configured for "straight through" pipeline installation and is virtually silent in operation.
In addition, the system can operate on steam pressures as low as 3bar.
Pursuit Dynamics owns the intellectual property underlying the novel system that is derived from a marine propulsion system and is the subject of 15 patent applications following three years' worth of research and development that has cost in excess of GBP 4 million.
Demonstrations of the technology are available at Pursuit's headquarters in Royston, Hertfordshire or anywhere in the UK with Pursuit's mobile field demonstration unit.
The PDX unit is driven by steam, which is already available in almost every keg washing plant throughout the world.
Neither high pressure nor high volume is necessary, and condensate does not impair the performance, so the PDX unit's distance from the steam generator is immaterial.
Steam is injected into a tube via a series of nozzles around the circumference.
Energy is input to the process fluid by momentum transfer of the steam, from the pressure drop when the steam condenses, and from the development of a controllable supersonic shock wave.
The shock wave zone can be generated across the full width of the process fluid, increasing the energy transfer and having a vigorous mixing effect.
Air can also be naturally entrained into the low-pressure zone to boost the performance, enhance the natural mixing effect and/or aerate the process fluid.
If the process fluid were plain water, the effect would simply be to pump the water, with the condensation energy of the steam causing a small temperature increase.
However, the process can be controlled so as to raise the temperature significantly higher, which would be the case for keg washing.
If appropriate materials are used in the construction of the PDX unit, and/or a corrosion-resistant liner or coating is employed, the device can be made impervious to hostile solutions, and the steam injection principle keeps the nozzles clean.
Flowrates vary from around 90kl/h from a 63mm-diameter unit down to 12kl/h from a 25mm unit, but units can readily be run in parallel, which means that there is no practical limit to maximum flowrates.
Another feature of the PDX unit is that the low-pressure zones can be used to entrain additional liquids, gases or powders into the process fluid, thereby eliminating the need for further pumps or compressors.
In the case of keg washing, caustic chemicals can easily be added to the water as it is being pumped into the cleaning tank or being recirculated by the PDX unit.
If the entrained material is added upstream, it becomes thoroughly mixed with the process fluid as it passes through the shock zone; less energetic mixing is achieved if the material is entrained downstream.
Another attribute of the PDX system that can be of advantage is the ability for a unit to be located within the cleaning tank, providing a both further heating and a very agitated circulation to assist the cleaning process.
A PDX system could readily be designed for installation with new keg washing plant, or it would be feasible to upgrade existing plant to take advantage of the improved process efficiency, reduced maintenance overhead and greater process reliability.
In addition, similar benefits stand to be gained through the application of the PDX technology to the internal cleaning of kegs.
Another area of the brewing process where the PDX system could be used to good effect is in transferring spent grain.
Because the PDX unit has a clear, parallel bore of full diameter, slurries - and solids suspended in liquids - are handled as effectively as liquids (tests have been successfully conducted on materials as diverse as spent grain, molasses and gravel).
Little or no cleaning is required after conveying the spent grain, and the controllable shock zone has an additional macerating effect on the material as it passes through, which eliminates the need for separate macerating equipment.
Further applications for the PDX system are also possible in bottling plant and, potentially, in the primary brewing processes.
Whatever role it performs within the brewing industry, the PDX system is environmentally friendly and, with no moving parts, it poses no risk of contamination to the process; substantial benefits are available for early adopters of this technology.
Pursuit Dynamics is currently looking for suitable partners to licence or adopt this system.
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