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P a g e
PRINCIPLES OF OPERATION
The machine consists of a motor/blower assembly, blower housing, a nozzle,
formulation tank, tank neck filter, metering valve, check valve and shutoff valve
(solenoid or manual, depending of the model). The various components are identified in
the fluid systems diagram and major components diagram.
The blower is a two-stage centrifugal compressor driven by a universal motor operating
at a speed of 20,000 rpm. The blower moves a large amount of air through the nozzle
system. The flexible hose is located between the nozzle and the blower housing to allow
easy orientation of the nozzle to direct the spray into hard to reach areas. The nozzle
has six (6) stationary fins, which direct the air to create a swirling effect of the air mass
as it leaves the nozzle. In the center of this exiting swirling air, a liquid supply spout tube
injects formulation. The formulation is sheared into tiny aerosol droplets and dispersed
into the atmosphere.
The liquid is delivered to the liquid spout by a combination of positive and negative
pressures. A negative pressure is generated in the nozzle by the exiting air mass and a
positive pressure is generated inside the blower housing and sampled to pressurize the
formulation tank. The positive pressure minimizes the effect of the variation of the flow
rate due to the difference in the static head of the liquid when the nozzle is at higher or
lower position.
The rate of flow is controlled by a metering valve located at the left side of the tank.
Generally, the sizes of the output droplets increase with increasing flow rates and with
increasing viscosity of the liquid being dispensed.
The check valve allows the airflow from the blower housing to the tank, and avoid any
return of pressurized air/vapor or liquid to the blower housing.
The vented tank cap in combination with the air coming from the blower housing, allow
a medium positive pressure inside the formulation tank when the machine is in
operation, and equalize the tank pressure to the atmospheric pressure in relatively short
period of time, when the machine is turn off.
