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781Mini Series Spray Valve
4
Introduction
The 781Mini precision Low Volume Low Pressure
(LVLP) liquid spray valve is designed for high transfer
efficiency without overspray or airborne mist and
provides consistent coating application of low-to-
medium viscosity fluids. 781Mini spray valves are
simple to use and will operate many millions of cycles
without maintenance.
The fluid body offers 360° rotational movement,
allowing the fluid inlet to be positioned in the best
orientation for fluid feed to the valve.
The valve’s unique quick-release (QR) clasp secures
the fluid body to the air cylinder body and can be
removed in seconds for fast change-out and easy
cleaning and maintenance of the valve’s wetted parts.
How the 781Mini Valve Operates
Input air pressure at 4.8 bar (70 psi) retracts the
piston and needle from the needle seat in the nozzle,
permitting fluid flow through the nozzle. At the same
time, nozzle air flows around the liquid exiting the
nozzle. This adjustable nozzle air creates a pressure
drop around the nozzle, causing the liquid to atomize
into fine droplets.
The amount sprayed is controlled by the valve open
time, reservoir pressure, and needle stroke. The area
of coverage is determined by the nozzle size and the
distance between the nozzle and the work surface.
Once the cycle is complete, air pressure is exhausted,
causing the piston spring to return the needle back to
its position in the nozzle, stopping fluid flow.
Fluid body
rotates for 360°
movement
QR clasp can be
removed for fast
valve change-out
Closed
Open
