Electro-Chemical Devices (ECD) CA6 Hardness Analyzer - Manual (Page 27)

loop reservoir the sample is at atmospheric pressure and this allows the sample pump to provide a
consistent sample delivery to the colorimetric cell. In addition, the fast-loop reservoir provides an extra
quantity of sample in case of an interruption in the sample flow.
The stainless steel drain tubing keeps a constant sample level inside the container. The sample flow
should be adjusted for a continuous sample overflow through the stainless steel drain tube thereby
providing ample circulation to avoid suspended solids accumulation in the reservoir. A small hole at the
top of the stainless steel drain tubing allows the fast-loop reservoir to be easily emptied for cleaning
purposes.
The Fast-Loop reservoir uses a level sensor to verify sample volume. The loss of sample triggers the level
switch which places the analyzer in stand-by mode at the end of the current measurement cycle. When
the sample flow returns and refills the reservoir, the analyzer will automatically start a new cycle.
2.4.2 Sampling Pump
Model CA-6 uses a Masterflex® peristaltic pump for sampling. The Model # of the pump is printed on the
cover and the Model # includes the two digit tubing size
designator. Proper diameter and material of the tubing must
be used for proper functioning of the CA-6 Analyzer, use only
ECD replacement tubing and parts. The pump is located in the
liquid enclosure.
2.4.3 3 Way Valve
The use of 3 Way Valves allows the CA-6 to perform automatic
operations. An operator can set up auto-calibration, auto-
validation or auto-cleaning functions. The valve is located in
the liquid enclosure.
2.4.4 Micro Peristaltic Pumps
The reagents are dispensed with “Micro Peristaltic Pumps“. Up to 4 pumps can be installed in the
analyzer, allowing the use of up to 4 different reagents. Every 1 second pulse of the pump allows a 0.05
ml dose of reagent. The pumps are located in the liquid enclosure.
2.4.5 Mixing Pump
The sample and reagents are mixed with a diaphragm pump. The liquids are pumped from the lower
part of the colorimetric cell to the upper part for a specified period of time. Flow direction (inlet / outlet)
of the pump is indicated with the symbols (V) and (Λ) on the pump body. The mixing pump is located in
the liquid enclosure.
2.4.6 Pinch Valve
The normally-closed pinch valve is used to control the draining or rinsing of the colorimetric cell. When
the valve is actuated it opens and drains the cell. The valve can be manually actuated by pressing the
black plastic face. The pinching jaws are sized for ⅜” O.D. Silicon or Viton tubing. The size and material of
the tubing is VERY IMPORTANT, use only ECD spares. The pinch valve is located in the liquid enclosure.
This tubing should be checked regularly for proper sealing.
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