Feature Hydraulics & pneumatics
downtime. Likewise, the use of safety blocks with integrated shut off valves allows each accumulator to be iso- lated and then discharged to a tank in a safe and controllable manner, using a lever operated discharge valve mounted on the block; or remotely, by means of a separate electrically controlled discharge valve.
Considerations
Another important consideration in product selection is the type of fittings used to terminate hydraulic hose assemblies. The traditional way of creating high strength terminations is known as ‘skiving’, in which the outer abrasion resistant sheath of the hose is cut away, allowing the hose connector to grip the reinforcing braid within the hose and the rubber hose itself. Skived joints are strong and reliable, but the process itself carries inherent risks that the inner hose or reinforcing braid will be damaged during the cut- ting process, compromising the ability of the hose to hold pressure. This can be avoided with modern connector designs such as Parker’s No-Skive system, which uses special connector designs, dies and crimping machines to assemble robust, reliable joints with no cutting necessary. Appropriate crimping equipment is available,
allowing repairs to be carried out in the most appropriate fashion for individual operators. Today, the No-Skive concept has even been extended into very high pressure applications. The company’s new Interlock No-Skive system, for example, has been designed to engage the tube into the spiral wire reinforce- ment used in high pressure hoses with superior holding power, to deliver excellent pull-out resistance and improve the cool-down leakage perfor- mance. The improved strength of the construction avoids any blow-off risk of the fittings under extreme conditions: the well-known compression issues
between hose and fitting are resolved by a specifically designed holding zone in the fittings. The fittings are also offered as a one-piece solution which prevents any kind of mounting error or the use of incorrect components during assembly.
A safe system
Despite the potential risks, a hydraulic system that is correctly specified, installed and maintained will be inherently safe and operate reliably. Not only is it vital that good operating practices are observed at all times to ensure the wellbeing of maintenance engineers and system operators, but the use of modern devices enhances the safety of hydraulic sys- tems still further to eliminate all risks, increasing uptime and productivity.
Parker’s No-Skive system
Parker Hannifin T: 00800 2727 5374
www.parker.com
Enter 208
‘The PED requires manufacturers of hydraulic equipment and components within the EU to take responsibility for the compliance of their products, and makes it necessary for them to supply a Certificate of Conformity with equipment to reassure machine builders and end users that the equipment is safe when operated for the intended purpose’
Quiet Operation Solenoid Valve
Whisper technology reduces noise by 50% Vacuum to 45psig pressure range Flows 4.4 SLPM air at 10psig Life of 250 million Cycles Operating temperature 40°F to 120°F
The quiet operation High Density Interface solenoid valve eliminates the inherent clicking sound in a typical solenoid valve. This new design uses "whisper" technology to achieve patient comfort and is ideal for medical applications flowing gas or air, such as dialysis machines, patient monitors, ventilators/ respirators, and other bedside medical devices.
SEND FOR OUR FREE PRODUCT CATALOGUE Lee Products Limited, 3 High Street, Chalfont St Peter, Gerrards Cross, Bucks. SL9 9QE
Tel: 01753 886664 Fax: 01753 889588
www.leeproducts.co.uk e-mail:
sales@leeproducts.co.uk Enter 8 12 MARCH 2011 Design Solutions Innovation in Miniature
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