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Installation & General Information
Moisture Probes to Fit All Mixers

These are the popular models suitable for flush or top mounting.

This 2¼" diameter probe with 1½" contact area should be flush mounted only. Use plain steel washers to shim the probe as required by thickness or mixer liner.

The operation of the moisture meter is based upon the principle of measuring in millivolts the conductivity of a small electrical current in the wet concrete mix. Water, together with dissolved minerals and chemicals make this mix an electrolyte, through which the current flows.

This conductivity of the mix is very susceptible to variables caused by changes in temperature, gradation and the mineral/chemical composition of all the ingredients. Accordingly, the factors affecting the instrument require close observation. If uniformity is to maintained, re-setting the meter dial is required as changes occur. The first batch in the morning should not be used to make settings or adjustments to the meter since it may be contaminated with oil or cleaning compounds.

The moisture probe or electrode located within the mixer is a part of the moisture meter's circuit. The probe is the open end of this circuit where the meter takes continuous readings of the conductivity of the mix.

The probe should be located in an area of the mixer where the scouring action of the mix will keep it clean. The concrete should NEVER be permitted to harden or pack over the probe. It should not be located in the path of a direct stream of water or calcium chloride solution.

Depending upon the meter manufacturer's recommendation, one or two probes per mixer should be used.

The head of a "flush" mounted probe should protrude a fraction past the liner plate surface to ensure proper scouring action.

A mixer liner bolt may be removed for "top-mounting". The probe assembly is sufficiently strong to keep the liner in place. Use moderate torque on hex nut, similar to tightening a spark plug.

For optimum reading results and maximum probe life, it is very important to maintain a clearance of 3/16 to 1/4 inches (or size of largest aggregate) between face of probe and edge of mixer or scraper blades as indicated on the sketch. Prior to operating the mixer, check to make sure all mixer blades clear the probe to prevent damage.

Daily or end of shift cleaning is a must. Cleaning is best done with a putty knife and wire brush. NO HAMMER!

The paint on the probe is cosmetic. A few turns of the mixer will clean the center contact and insulator area or you may use emery paper prior to installing the probe.


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