Gypsum Moisture Sensor

Raw/Synthetic Gypsum and Moisture Concerns

As a primary core material used in the manufacture of drywall (due in part to its natural fire resistance), it’s also used as an ingredient in cement, by agriculture users for soil replenishment, in plaster manufacturing, and as an ingredient in some paints and food products, gypsum’s moisture content is an incredibly important factor to its successful incorporation into these products.

Raw gypsum starts out at about 21% water by weight (50% by volume). To produce plaster or wallboard, raw gypsum must be calcined, or heated to about 350 def. F in order to remove most of the water. The gypsum is then slightly re- hydrated and various fibers and additives are added to improve strength, speed of hardening and to hinder mildew and mold growth.

If the gypsum is not calcined at the appropriate temperature (to reduce moisture from about 21% to 1% or below), it will not combine properly with the fibers and additives that are added to improve quality. Should this occur, the production batch is lost and must be recycled at great expense due to required operator wages, lost electrical services, and increased equipment usage and maintenance. Bad product might also have to be scrapped necessitating land fill costs.

Measurement of Moisture is Critical

Because this measurement of moisture is so critical, we’ve developed sensors that offer instantaneous measurement of gypsum in its raw state and at all the various stages of the manufacturing process. Our sensors also work seamlessly for synthetic gypsum as well. Our OMNIR device is perfect for mounting over your conveyor belt while output signals are available for automatic adjustment of line speed or calciner temperatures depending on the analysis of incoming rock moisture content.

Finished gypsum board must also be monitored for appropriate moisture content. Finna Sensors makes a full range of RF (radio frequency) moisture meters in various flat-plate sensors for use in the drying kiln or for finished board. These sensors come in various sizes to fit whatever your production requirements may be.