Apparatus and process for microwave moisture analysis

Claim 1

An apparatus for analyzing a sample of moisture containing material comprising: first means for forming a chamber effectively preventing reflection of microwave energy; second means defining a sample cell space for retaining a moisture containing sample material, said second means being arranged to be disposed in said chamber; third means for transmitting microwave energy through said second means in said chamber; fourth means for receiving radiation transmitted through said space and providing a first output signal representative of water weight in a sample material therein; fifth means coupled to said first and second means for providing a second output signal representing the weight of a sample material including the water weight retained in said space; sixth means for receiving said first and second output signals and providing a third output signal representing the percent by weight moisture content of material retained in said space; and seventh means for measuring the temperature of the sample material retained in said space during a weight sensing operation and providing a fourth output signal.

Claim 2

An apparatus for analyzing a sample of moisture containing material comprising: first means for forming a chamber effectively preventing reflection of microwave energy; second means defining a sample cell space for retaining a moisture containing sample material, said second means being arranged to be disposed in said chamber; third means for transmitting microwave energy through said second means in said chamber; fourth means for receiving radiation transmitted through said space and providing a first output signal representative of water weight in a sample material therein; fifth means coupled to said first and second means for providing a second output signal representing the weight of a sample material including the water weight retained in said space; sixth means for receiving said first and second output signals and providing a third output signal representing the percent by weight moisture content of material retained in said space; and seventh means for measuring the temperature of the sample material retained in said space during a weight sensing operation and providing a fourth output signal.

Claim 15

An apparatus for analyzing a sample of moisture containing material comprising: a source of microwave energy of predetermined frequencies; transmitter means coupled to said source for transmitting said microwave energy; wall means forming a chamber effectively preventing reflection of microwave energy; sample cell means removably positioned in said chamber in the path of said transmitted microwave energy for retaining a sample of moisture containing material in the path of said microwave energy such that said transmitted microwave energy is attenuated by moisture in said sample in said path, said sample cell means being substantially transparent to microwave energy at said predetermined frequencies; receiver means positioned to receive microwave energy transmitted through said chamber by said transmitter means and providing an output representing the microwave energy transmitted through said sample cell means; means coupled to said receiver means for providing a signal corresponding to the output signal representing the weight of the sample material retained therein; weighing means coupled to weigh said sample cell means and a sample material retained therein for providing an output signal representing the weight of the sample material retained therein; temperature sensing means coupled to said sample cell means for detecting the temperature of the sample material retained in said sample cell means during the transmission of microwave energy therethrough; output means coupled to simultaneously receive said output signals representing water weight, sample weight and sample material temperature for calculating and providing an output signal representing percent by weight moisture of a sample material; and anechoic chamber means enclosing each of said transmitter means, receiver means and sample cell means within a chamber constructed and designed to absorb microwave radiation at said predetermined frequencies to reduce microwave reflections and emissions within said chamber.

Claim 16

An apparatus for analyzing a sample of moisture containing material comprising: a source of microwave energy of predetermined frequencies; transmitter means coupled to said source for transmitting said microwave energy; wall means forming a chamber effectively preventing reflection of microwave energy; sample cell means removably positioned in said chamber in the path of said transmitted microwave energy for retaining a sample of moisture containing material in the path of said microwave energy such that said transmitted microwave energy is attenuated by moisture in said sample in said path, said sample cell means being substantially transparent to microwave energy at said predetermined frequencies; receiver means positioned to receive microwave energy transmitted through said chamber by said transmitter means and providing an output representing the microwave energy transmitted through said sample cell means; means coupled to said receiver means for providing a signal corresponding to the output signal representing the weight of the sample material retained therein; weighing means coupled to weigh said sample cell means and a sample material retained therein for providing an output signal representing the weight of the sample material retained therein; temperature sensing means coupled to said sample cell means for detecting the temperature of the sample material retained in said sample cell means during the transmission of microwave energy therethrough; output means coupled to simultaneously receive said output signals representing water weight, sample weight and sample material temperature for calculating and providing an output signal representing percent by weight moisture of a sample material; and anechoic chamber means enclosing each of said transmitter means, receiver means and sample cell means within a chamber constructed and designed to absorb microwave radiation at said predetermined frequencies to reduce microwave reflections and emissions within said chamber.