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©Godiva Ltd. Our policy is one of continuous development. We therefore reserve the
right to amend specifications without notice or obligation.
SYSTEM OVERVIEW
The WT_C or WS_C is a Compressed Air Foam System comprising of three major
components – Air compressor, FoamLogix (foam proportioning unit) and Manifold
(foam mixing and control system).
For
2.1A
FoamLogix components are located behind the World Series pump, above
the bearing housing and gearbox. The
3.3
FoamLogix pump / motor assembly
however is separate from the WT(S)-C pump and is designed to be remote (vehicle)
mounted.
A metered amount of foam is introduced into the Manifold and mixed with water from
the pump discharge manifold. The foam and water blend is then fed to a control valve
(ARC) where wet or dry foam may be selected (air ratio control section of manifold).
Compressed air is then injected and the resulting foam / water / air combination is
completely mixed by the X-mixers during discharge.
Safety interlocks are provided to ensure that:
1. Foam cannot be introduced unless water is flowing through the unit.
2. ‘Slugging’ (unmixed air and water) in the discharge line) is prevented. Air
cannot be injected in the absence of foam and water.
3. Air injection when the foam tank is empty is prevented. Foam tank low level
switches are provided and MUST be fitted.
Compressor
The rotary twin-screw compressor is rated at 50 scfm @ 7 bar and is driven by a
Polydrive belt. The compressor is engaged, or disengaged from the pump drive, via
an electro-magnetic clutch, being operated by the CAFS selector switch.
Compressor lubricating oil is cooled by water taken from the main pump, via the
water supply line; cooling water being supplied from pump delivery and returned to
pump suction. The compressor will reject approx. 8.0 kW of heat energy to cooling.
The installer must consider this additional thermal load.
When the compressor is stationary, residual system pressure is vented by a blow-
down valve.
NOTE:
The compressor should not be run without cooling water.
Manifold
The manifold incorporates an air ratio control valve through which degrees of wet or
dry foam mixture can be selected. Compressed air is then injected and the resulting
foam / water / air combination is thoroughly mixed by the X-mixers during discharge.
CAFS units are best suited for use with Fresh Water.