Direct-fired kiln furnace control system

Claim 2

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, and a duct coupling heated furnace gases to the inlet of said kiln chamber, c. spray means in said kiln furnace for injecting water for vaporization into said heated furnace gases, d. intake air control means for adjusting the relative constituents of fresh ambient air and tempering heated air returning from said kiln chamber, the mixture of which constituents is supplied as intake air to said furnace, and e. controller means for regulating the operation of said intake air control means during periods when water is interjected into said heated furnace gases by said spray means, whereby the caloric heat content of said furnace gases is maintained at a level sufficient to effect a rapid and substantially complete vaporization of said water spray therein.

Claim 3

The kiln system of claim 1 further including a passageway provided with an adjustable damper coupling said furnace duct directly to said furnace air intake for internally recirculating within said furnace a selectable portion of said heated furnace gases, the operation of said adjustable damper also being regulated by said controller means.

Claim 4

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having a burner for heating gases and a spray means for injecting water for vaporization into said heated furnace gases for increasing the moisture content thereof, said heated and moisturized furnace gases being thereafter supplied to said kiln chamber for circulation therethrough, c. fan means controlling the rate of flow of said gases through said furnace, and d. controller means for regulating the operation of said fan means during periods when water spray is added to said furnace gases, whereby the caloric heat content of said furnace gases is maintained at a level sufficient to effect a rapid and substantially complete vaporization of said water spray therein.

Claim 5

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having a burner for heating gases and a spray means for injecting water for vaporization into said heated furnace gases for increasing the moisture content thereof, said heated and moisturized furnace gases being thereafter supplied to said kiln chamber for circulation therethrough, c. fan means controlling the rate of flow of said gases through said furnace, and d. controller means for regulating the operation of said fan means during periods when water spray is added to said furnace gases, whereby the caloric heat content of said furnace gases is maintained at a level sufficient to effect a rapid and substantially complete vaporization of said water spray therein.

Claim 6

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, and a duct coupling heated furnace gases to the inlet of said kiln chamber, c. spray means in said kiln furnace for injecting water for vaporization into said heated furnace gases, d. an adjustable damper coupling said furnace duct directly to said furnace air intake for internally recirculating within said furnace a selectable portion of said heated furnace gases, and e. controller means for regulating the operation of said adjustable damper during periods when water is interjected into said heated furnace gases by said spray means, whereby the caloric heat content of said furnace gases is maintained at a level sufficient to effect a rapid and substantially complete vaporization of said water spray therein.

Claim 7

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, and a duct coupling heated furnace gases to the inlet of said kiln chamber, c. spray means in said kiln furnace for injecting water for vaporization into said heated furnace gases, d. an adjustable damper coupling said furnace duct directly to said furnace air intake for internally recirculating within said furnace a selectable portion of said heated furnace gases, and e. controller means for regulating the operation of said adjustable damper during periods when water is interjected into said heated furnace gases by said spray means, whereby the caloric heat content of said furnace gases is maintained at a level sufficient to effect a rapid and substantially complete vaporization of said water spray therein.

Claim 8

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. fan means controlling the rate of flow of said furnace gases through said furnace, d. intake air control means for adjusting the relative constituents of fresh Ambient air and tempering heated air returning from said kiln chamber, the mixture of which constituents is supplied as intake air to said furnace, e. a passageway provided with an adjustable damper coupling said duct directly to said air intake for bypassing said furnace chamber and internally recirculating within said furnace a selectable portion of said heated furnace gases, f. a pair of sensors positioned in said kiln chamber for monitoring respectively the instantaneous temperature and humidity conditions prevailing therein, and g. controller means connected to receive signals from said sensor pair and acting on said water spray means, said fan means, said intake air control means, and said adjustable damper, whereby the operation of said kiln furnace is regulated so as to restore and maintain desired predetermined temperature and humidity conditions in said kiln chamber.

Claim 9

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. fan means controlling the rate of flow of said furnace gases through said furnace, d. intake air control means for adjusting the relative constituents of fresh Ambient air and tempering heated air returning from said kiln chamber, the mixture of which constituents is supplied as intake air to said furnace, e. a passageway provided with an adjustable damper coupling said duct directly to said air intake for bypassing said furnace chamber and internally recirculating within said furnace a selectable portion of said heated furnace gases, f. a pair of sensors positioned in said kiln chamber for monitoring respectively the instantaneous temperature and humidity conditions prevailing therein, and g. controller means connected to receive signals from said sensor pair and acting on said water spray means, said fan means, said intake air control means, and said adjustable damper, whereby the operation of said kiln furnace is regulated so as to restore and maintain desired predetermined temperature and humidity conditions in said kiln chamber.

Claim 10

A kiln system according to claim 5 further including a third sensor positioned in said furnace so as to measure the temperature of said heated furnace gases and connected as a signal input to said controller means, whereby the operation of said fan means, said intake air control means and said damper are regulated so as to reduce the temperature of said heated furnace gases when the signals received from said third sensor indicate that the temperature of said gases is closely approaching a predetermined maximum level.

Claim 11

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. intake air control means for adjusting the relative constituents of fresh ambient air and tempering heated air returning from said kiln chamber, the mixture of which constituents is supplied as intake air to said furnace, d. a first sensor located in said kiln chamber for measuring the dry bulb temperature of the gases circulating therein, e. a second sensor located in said kiln chamber for measuring the wet bulb temperature of said circulating kiln gases, f. a regulator connected to receive signals from said first and second sensors and generating a pair of ''''heat'''' and ''''humidity'''' output signals indicating, respectively, the instantaneous heat and humidity requirements of said circulating kiln gases as determined by comparison of said sensor signals with predetermined settings of said regulator, and g. a controller connected to said regulator containing circuit means which actuate said spray means when increased humidity is needed and which regulate the operation of said intake air control means in response to the greater of the respective magnitudes of said ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 12

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. intake air control means for adjusting the relative constituents of fresh ambient air and tempering heated air returning from said kiln chamber, the mixture of which constituents is supplied as intake air to said furnace, d. a first sensor located in said kiln chamber for measuring the dry bulb temperature of the gases circulating therein, e. a second sensor located in said kiln chamber for measuring the wet bulb temperature of said circulating kiln gases, f. a regulator connected to receive signals from said first and second sensors and generating a pair of ''''heat'''' and ''''humidity'''' output signals indicating, respectively, the instantaneous heat and humidity requirements of said circulating kiln gases as determined by comparison of said sensor signals with predetermined settings of said regulator, and g. a controller connected to said regulator containing circuit means which actuate said spray means when increased humidity is needed and which regulate the operation of said intake air control means in response to the greater of the respective magnitudes of said ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 13

A kiln system according to claim 7 further including a passageway provided with an adjustable damper coupling said furnace duct to said furnace air intake for internally recirculating through said furnace a selectable portion of said heated furnace gases, the operation of said adjustable damper also being regulated by said controller means in response to the greater of the respective ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 14

A kiln system according to claim 7 further including a fan means controlling the rate of flow of said furnace gases through said furnace, the operation of said fan means also being regulated by said controller means in response to the greater of the respective ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 15

A kiln system according to claim 7 including a third sensor positioned so as to measure the temperature of said heated furnace gases and connected as a signal input to said circuit Means in said controller whereby, in the event the temperature of said heated furnace gases closely approaches a predetermined safety threshold, said third sensor signal acts an an override on the operation of said controller so as to regulate said furnace air intake means in a manner so as to reduce the temperature of said heated furnace gases.

Claim 16

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. means controlling the rate of flow of said furnace gases through said furnace, d. means for controlling the temperature of the intake air supplied to said furnace, e. a pair of sensors positioned in said kiln chamber for monitoring respectively the instantaneous temperature and humidity conditions prevailing therein, and f. controller means connected to receive signals from said sensor pair and acting on said water spray means, said fan means and said intake air control means, whereby the operation of said kiln furnace is regulated so as to restore and maintain desired predetermined temperature and humidity conditions in said kiln chamber.

Claim 17

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. means controlling the rate of flow of said furnace gases through said furnace, d. means for controlling the temperature of the intake air supplied to said furnace, e. a pair of sensors positioned in said kiln chamber for monitoring respectively the instantaneous temperature and humidity conditions prevailing therein, and f. controller means connected to receive signals from said sensor pair and acting on said water spray means, said fan means and said intake air control means, whereby the operation of said kiln furnace is regulated so as to restore and maintain desired predetermined temperature and humidity conditions in said kiln chamber.

Claim 18

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. an adjustable damper coupling said furnace duct to said furnace air intake for internally recirculating through said furnace a selectable portion of said heated furnace gases, d. a first sensor located in said kiln chamber for measuring the dry bulb temperature of the gases circulating therein, e. a second sensor located in said kiln chamber for measuring the web bulb temperature of said circulating kiln gases, f. a regulator connected to receive signals from said first and second sensors and generating a pair of ''''heat'''' and ''''humidity'''' output signals indicating, respectively, the instantaneous heat and humidity requirements of said circulating kiln gases as determined by comparison of said sensor signals with predetermined settings of said regulator, and g. a controller connected to said regulator containing circuit means which actuate said spray means when increased humidity is needed and which regulate the operation of said adjustable damper in response to the greater of the respective magnitudes of said ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 19

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, a spray means for injecting water for vaporization into heated furnace gases for increasing the moisture content thereof, and a duct for supplying said heated and moisturized furnace gases to said kiln chamber for circulation therethrough, c. an adjustable damper coupling said furnace duct to said furnace air intake for internally recirculating through said furnace a selectable portion of said heated furnace gases, d. a first sensor located in said kiln chamber for measuring the dry bulb temperature of the gases circulating therein, e. a second sensor located in said kiln chamber for measuring the web bulb temperature of said circulating kiln gases, f. a regulator connected to receive signals from said first and second sensors and generating a pair of ''''heat'''' and ''''humidity'''' output signals indicating, respectively, the instantaneous heat and humidity requirements of said circulating kiln gases as determined by comparison of said sensor signals with predetermined settings of said regulator, and g. a controller connected to said regulator containing circuit means which actuate said spray means when increased humidity is needed and which regulate the operation of said adjustable damper in response to the greater of the respective magnitudes of said ''''heat'''' and ''''humidity'''' signals received from said regulator.

Claim 20

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, and a duct for supplying heated furnace gases to said kiln chamber for circulation therethrough, c. an adjustable damper coupling said furnace duct directly to said furnace air intake for bypassing said kiln chamber and internally recirculating within said furnace a selectable portion of said heated furnace gases, d. temperature sensor means located in said kiln chamber for monitoring the temperature of said circulating kiln gases, and e. controller means connected to receive signals from said temperature sensor means and regulating the operation of said adjustable damper in response to heat demand requirements for said furnace.

Claim 21

In a direct-fired kiln system, the combination comprising a. a kiln chamber for drying and conditioning material, b. a kiln furnace having an air intake, a burner, and a duct for supplying heated furnace gases to said kiln chamber for circulation therethrough, c. an adjustable damper coupling said furnace duct directly to said furnace air intake for bypassing said kiln chamber and internally recirculating within said furnace a selectable portion of said heated furnace gases, d. temperature sensor means located in said kiln chamber for monitoring the temperature of said circulating kiln gases, and e. controller means connected to receive signals from said temperature sensor means and regulating the operation of said adjustable damper in response to heat demand requirements for said furnace.