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Fixed-Ratio
The volumetric ratio of "A" to "B" is determined by the size of the metering pumps. To
change the ratio requires a pump replacement with one of another size.
Variable-Ratio
The volumetric ratio of "A" to "B" is determined by both the size of the metering pumps and
the length of the stroke of the "B" pump. Both pumps are fixed in position but a ratio
control adjustment determines the length of the metering stroke of the "B" pump in
relationship to the "A" pump metering stroke.
The "B" pump shaft is connected to a carriage assembly with an adjustable drive beam
connector that controls the length of travel of the carriage assembly. This in turn controls
the length of stroke of the "B" pump.
By moving the ratio control adjustment toward the pivot point, the shorter the stroke
of the "B" pump and the wider the ratio of "A" to "B". By moving the ratio control
adjustment away from the pivot point, the longer the stroke of the "B" pump and the closer
the ratio of "A" to "B".
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