Spray systems
Page 62
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Complete wall-mounted, hot, airless-spray systems can now be supplied by Berk Ltd. from modular pump units, heaters and gun stations within the Graco range.
The systems comprise a neat steel cabinet, within or alongside which are mounted the pump, one or more heaters, all necessary regulating equipment. and fluid supply, outlet and drain hoses. The assembly is ready for immediate wall mounting. Comple mentary wall-mounted gun stations include a gun hanger, hp back-pressure regulator. fluid manifold and hose assembly.
Each system is assembled to meet output requirements. Any one of five pumps can be selected to give outputs of from 7 g.p.m.
to g.p. m. at various atomizing pressures, the choice being guided by the number of gun stations, type of coating and other variables. The ancillary equipment will be designed to bring the paint to the gun nozzle at the "underboiltemperature—that is just below the boiling-point of the lowest boiling solvent in the coating. This offers the maximum practical reduction of material viscosity and surface tension, without thinning. And as an alternative to a wall-mounted unit, under-boil systems can be trolley-mounted, when they are known as Vulcan portable units.
A Vulcan portable under-boil consists of one of two pumps—a President 28:1 2 g.p.m. pump or a President 15:1 1+ g.p.m. pump—mounted over a Vis-Con heater with all ancillary equipment on a la rge-tyred steel chassis. The standard equipment includes 25ft of nylon circulating hose and a Graco reflex gun—the Graco "special" which features an airoperated trigger to give instant spray control.
Reflex guns are recommended for all under-boil systems because they remove the last of the three variables likely to affect the quality of a finished coating. The first variable, viscosity', is main tained constant by the Vis-Con heater despite outside conditions. The second, pressure, is instantly adjusted by Graco high-pressure modulating controllers. The third. operator technique, is modified by the instant full-on/full-off effect of the reflex gun trigger. A soft spray reaches out with virtually no bounce-back or over-spray. Spitting is greatly reduced and -spot aim" improved, even in the hands of inexperienced operators.
Made by: Berk Ltd., Engineering Division, Paramount House, 75 Uxbridge Road, Ealing, London, W5..