Water Hydraulics
What is Water Hydraulics?
By definition, a 'water hydraulic' system should use water as the hydraulic fluid. The physical properties of water are different to oil, so if water was used in an oil hydraulic system the moving parts would fail very rapidly.
Water hydraulic pumps, valves and actuators are specifically designed to operate on fluids with low viscosity, high vapour pressure and poor lubrication properties. The system must also be designed to allow for the physical properties of water. Pipe sizing, temperature control, the use of corrosion resistant materials and many other factors are different when using water as the hydraulic fluid.
Why Water Hydraulics?
Water does not catch fire: Wherever there is heat, sparks or flame, a water hydraulic system can completely eliminate the risk of the hydraulic fluid catching fire. If factories burn down, production is lost, insurance costs increase and lives are at risk!
Product contamination: If there is a risk of the hydraulic fluid spilling onto the product, in the manufacturing process, the finished product may be useless. A water hydraulic system can reduce scrap and waste.
Environmental pollution: Water is natural so it does not pollute the environment. Legislation on contamination of our soil, rivers and oceans will get tougher, not easier. Water hydraulic systems can reduce pollution and the cost of cleaning our environment
Fluid costs: Water costs very little, and does not wear out, so it does not have to be replaced. Water is readily available and it eliminates storage costs. Disposal costs are low, additives and impurities in industrial water may have to be removed as part of the recycling process and local water companies can be consulted on this.
Energy saving: Water has a low viscosity and low compressibility, making it an excellent transmitter of energy in a hydraulic system. Pressure drops in pipes and valves are reduced. Water hydraulic systems use valves with very low internal leakages, increasing efficiency.
Water as a Hydraulic Fluid
Some water hydraulic systems use water, without additives, as the hydraulic fluid. It is common to mix additives with water to improve the physical properties when using it as a hydraulic fluid:
Improve lubrication
Reduce Corrosion
Control bacterial and fungal growth
Water Hydraulics systems allow additives where the fluid is high water based (typically with a minimum of 95% water) and with a viscosity not exceeding 5 centistokes. This is around the limit where oil hydraulic components do not function or give an unacceptably short service life.
Where is Water Hydraulics used?
Steel Industry:- Steelmaking, continuous casters, foundries, furnaces, hot saws, rolling mills, forging presses, descaling, planishing and forming presses.
Non Ferrous Industry:- Aluminium rolling mills, aluminium and copper extrusion presses.
Mining Industry:- Roof supports, cutting machinery, dust suppression.
Offshore Industry:- Oil and gas line valve actuators, emergency shut down (ESD) systems, pipeline repair, wellhead controls, ROV sub-sea vehicles.
Ceramics Industry:- Presses and cleaning systems, grinding wheel manufacture.
Automotive Industry:- Presses, tyre manufacture, brake pad manufacture, welding robots, hydroforming of body components.
Wood and Paper:- Wood chip board presses, laminate presses, bark removers, paper presses.
Textile Industry:- Dye impregnation, non-woven fabric presses, cloth cutting, finishing presses.
Power Industry:- Hydro-electric valve control. Nuclear Industry:- Robots, verification plant, skip wash systems.
Food Industry:- Fruit presses, vegetable and potato washing, ovens, food processing machinery.
More Information on Water Hydraulics
BFPA has produced two publications on water hydraulics: P75 Water Hydraulics - A guide to products and suppliers in the UK and P82 Water Hydraulics - A Technical Guide. Contact the BFPA for further details. A number of water hydraulic companies are members of the BFPA and links to these companies can be found on the BFPA website 'Search For' facility.
BFPA Water Hydraulics Committee - 2003 Report
History and membership - Meeting twice a year since 13th June 1996 the Water Hydraulics Committee has Technical Committee status within the BFPA. The Water Hydraulic Committee works closely with the BFPA Fluids Committee (TC16) and the Chairmen or Vice Chairmen of each of these Committees attend both meetings. The Water Hydraulic Committee has a current membership of 13 and is planning a recruitment drive to increase both Water Hydraulic Committee Committee and BFPA membership (FP003947). There is currently a vacancy for a Vice Chairman for the Water Hydraulic Committee.
ISO - The Water Hydraulic Committee is not working independantly on ISO standards, as this work is already being carried out very effectively by other BFPA Committees. The Water Hydraulic Committee provides an additional source of expertise in the field of HFA fluids and in 2003 this has contributed to the proposed revision of ISO6743-4 (FP003836). Water Hydraulic Committee will continue to work with TC16 on other ISO standards where there is a common interest. This co-operation could be applied to other committees in the future, where there is a joint interest and the specialist expertise of the Water Hydraulic Committee can make a useful contribution.
BFPA Guidelines - The Water Hydraulic Committeehas produced two BFPA Guidelines to date: BFPA/P75 (2nd revision 2002) - Water Hydraulics, A guide to products and suppliers in the UK. BFPA/P82 1999 - Water Hydraulics, A technical guide.
The Hot Billet Test - This is a fluid flammability test, with the origins of the concept from British Steel Corporation (now Corus Group Plc). The original intention was to produce this test as a recognised standard, BS or ISO. The project has been held up from progressing to a standard because of lack of funding, so it may be issued as a BFPA Guideline in the future (FP003560).
Statistics - The BFPA carries out an independent survey of the UK market for water hydraulics, by industry sector and product category. There are 10 to 14 respondents, including most of the major suppliers. This has monitored market trends for water hydraulics from 1996 to 2003.
Publicity - The Water Hydraulic Committee has produced a ‘Water Hydraulics' page for the BFPA website ‘www.bfpa.co.uk/water.html'. There are on-going discussions within the Water Hydraulic Committee for a joint ‘Water Hydraulic' display at the 2004 Motion and Control exhibition in the NEC. It is planned to extend BFPA/P75 to include application pages for water hydraulics. The Water Hydraulic Committee is to approach the BFPA publicity committee to offer proposals for the next revision of the publication ‘BFPA - Fluid Power at the Forefront'.
BFPA/Coxmoor Series - The Water Hydraulic Committee Chairman has already forwarded the completed chapter on Water Hydraulics to Don Seddon. It is hoped this will be published in 2004 as part of the 2nd book in the series, or as a ‘stand alone' publication.
Training and Education - The Water Hydraulic Committee have entered preliminary discussions with NFPC to include water hydraulics into some of the training modules. Proposals for a water hydraulics conference have also been discussed.
Liason with other bodies - The University of Bath was a member of the Water Hydraulic Committee during the early years but their membership has lapsed. HSE delegates attend Water Hydraulic Committee meetings. Corus Group Plc (formerly British Steel Corporation) is an active member of the WHC. The BFPA/WHC has regular contact and correspondence with the NFPA and VDMA Water Hydraulic committees. In December 2003 a delegation from the Japan Fluid Power Association, Water Hydraulics Committee visited the BFPA for a meeting with our Water Hydraulics Committee, initiating an exchange of information.
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