Wash pump
Page 74
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A high-pressure wash pump (the P 400) capable of delivering a 2.1/2 gal/min jet of water at 1,000 p.s.i. has been developed by A. G. Wild and Co. Ltd. Its working principle is based on the use of a Tektro hydraulic valve as a reciprocating control element. The valve is supplied by Applied Power (UK) Ltd., Watford.
It is claimed by the maker that the pump removes grease and dirt more efficiently than a steam cleaner and at a lower cost without the limitations imposed by the need to provide power to heat the water.
The valve is based on a standard Tektro three-position fourway type. Its single spool shifts once every second so as to direct oil alternately to each of two pressure chambers. A flexible diaphragm divides each chamber internally into oil and water compartments. Detergents, disinfectants and other chemical solutions can be used instead of water, without causing damage to the working parts.
Oil pressure on one of the diaphragms causes it to distend, forcing water out of that chamber and into the outlet pipe under pressure. In the meantime, because the two diaphragms are linked mechanically and move in concert, water is being sucked into the other chamber. At the appropriate moment, the same linkage acts through a changeover lever and a "flirt" spring to move the valve spool, thereby repeating the sequence in opposite chambers. In this manner a constant head of high pressure water is generated at the outlet nozzle.
The P 400 wash pump is driven by an electric motor or a petrol engine, depending on whether the unit is required to operate close to or remote from a power supply. In either case the prime mover is coupled directly to an hydraulic gear pump, which supplies oil through the control valve at the required rate.
Made by: A. G. Wild and Co., Ltd., Sheffield.