Apparatus and method for distributing material being processed over a furnace hearth floor

Claim 1

In a furnace having at least a single substantially horizontal hearth, the combination comprising a Rotatable center shaft extending up through the center of said hearth, at least one rabble arm secured to the center shaft and extending radially outwardly over said hearth, means for providing a radial flow component of material being processed on said hearth, and independent means for providing a circumferential flow component of the material being processed on said hearth with respect to said means for providing the radial flow component, whereby when said center shaft is rotated the flow of material being processed is distributed across the entire hearth area.

Claim 26

A method of processing material in a single hearth furnace having a center shaft extending up through the center of said hearth, at least one rabble arm secured to the center shaft and extending radially outwardly over said hearth, said method comprising the steps of introducing said material onto said hearth, urging said material to move across said hearth with a radial flow component, while simultaneously urging said material to move across said hearth with an independnet circumferEntial flow component, whereby said material is caused to flow across the entire hearth area without forming stagnant zones.

Claim 27

A method of processing material in a single hearth furnace having a center shaft extending up through the center of said hearth, at least one rabble arm secured to the center shaft and extending radially outwardly over said hearth, said method comprising the steps of introducing said material onto said hearth, urging said material to move across said hearth with a radial flow component, while simultaneously urging said material to move across said hearth with an independnet circumferEntial flow component, whereby said material is caused to flow across the entire hearth area without forming stagnant zones.

Claim 28

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, urging said material to move across one of the upper hearths with a radial flow component, while simultaneously urging said material to move across said one hearth with an independent circumferential flow component, to cause said material to flow across the entire area of said one hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said one hearth and down its respective drop hole to the next lower hearth and withdrawing said material from the bottom of said furnace.

Claim 29

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, urging said material to move across one of the upper hearths with a radial flow component, while simultaneously urging said material to move across said one hearth with an independent circumferential flow component, to cause said material to flow across the entire area of said one hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said one hearth and down its respective drop hole to the next lower hearth and withdrawing said material from the bottom of said furnace.

Claim 32

A method of processing sewage sludge in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing wet sewage sludge at the top of said furnace, passing said wet sludge downwardly through said furnace for drying the sludge by urging said sludge to move across one of the uppermost hearths with a radial flow component while simultaneously urging said sludge to move across said one hearth with an independent circumferential flow component, to cause said sludge to flow across the entire area of said one hearth in a distributed manner towards its associated drop hole, and successively passing said sludge across each hearth below said one hearth and down its respective drop hole to the next lower hearth, while maintaining the sludge in substantially the same state of dryness at any given diameter around each hearth in said furnace while applying heat to more than one hearth at controlled rates to effect said drying of the sludge.

Claim 33

A method of processing sewage sludge in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing wet sewage sludge at the top of said furnace, passing said wet sludge downwardly through said furnace for drying the sludge by urging said sludge to move across one of the uppermost hearths with a radial flow component while simultaneously urging said sludge to move across said one hearth with an independent circumferential flow component, to cause said sludge to flow across the entire area of said one hearth in a distributed manner towards its associated drop hole, and successively passing said sludge across each hearth below said one hearth and down its respective drop hole to the next lower hearth, while maintaining the sludge in substantially the same state of dryness at any given diameter around each hearth in said furnace while applying heat to more than one hearth at controlled rates to effect said drying of the sludge.

Claim 34

A method of processing sewage sludge in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed toward the outer periphery thereof, said method comprising the steps of introducing wet sewage sludge at the top of said furnace, passing said wet sewage sludge to a first zone in the upper portion of said furnace for drying the sludge by urging said sludge to move across the uppermost hearth with a radial flow component while simultaneously urging said sludge to move across said uppermost hearth with an independent circumferential flow component, to cause said sludge to flow across the entire area of said uppermost hearth in a distributed manner towards its associateD drop hole, and successively passing said sludge across each hearth below said uppermost hearth and down its respective drop hole to the next lower hearth in said first zone, while maintaining the sludge in a substantially the same state of dryness at any given diameter around across hearth in said first zone, passing said so-dried sludge to a second zone in the lower portion of said furnace for incinerating the sludge by successively passing said sludge across each hearth and down its respective drop hole to the next lower hearth in said second zone, while maintaining the sludge in substantially the same state of incineration at any given diameter around each hearth in the second zone, while applying heat to more than one hearth at controlled rates to effect said drying and incineration of the sludge.

Claim 35

A method of processing sewage sludge in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed toward the outer periphery thereof, said method comprising the steps of introducing wet sewage sludge at the top of said furnace, passing said wet sewage sludge to a first zone in the upper portion of said furnace for drying the sludge by urging said sludge to move across the uppermost hearth with a radial flow component while simultaneously urging said sludge to move across said uppermost hearth with an independent circumferential flow component, to cause said sludge to flow across the entire area of said uppermost hearth in a distributed manner towards its associateD drop hole, and successively passing said sludge across each hearth below said uppermost hearth and down its respective drop hole to the next lower hearth in said first zone, while maintaining the sludge in a substantially the same state of dryness at any given diameter around across hearth in said first zone, passing said so-dried sludge to a second zone in the lower portion of said furnace for incinerating the sludge by successively passing said sludge across each hearth and down its respective drop hole to the next lower hearth in said second zone, while maintaining the sludge in substantially the same state of incineration at any given diameter around each hearth in the second zone, while applying heat to more than one hearth at controlled rates to effect said drying and incineration of the sludge.

Claim 36

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, rabbling with a plurality of rabble teeth depending from the rabble arms in the uppermost hearth through said material to be processed and urging said material to move across the uppermost hearth with a radial flow component, while simultaneously sweeping chains disposed between adjacent rabble arms associated with the uppermost hearth through the material to urge said material to move across the uppermost hearth with a circumferential flow component, to cause said material to flow across the entire area of said uppermost hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said uppermost hearth and down its respective drop hole to the next lower hearth, and withdrawing said material from the bottom of said furnace.

Claim 37

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, rabbling with a plurality of rabble teeth depending from the rabble arms in the uppermost hearth through said material to be processed and urging said material to move across the uppermost hearth with a radial flow component, while simultaneously sweeping chains disposed between adjacent rabble arms associated with the uppermost hearth through the material to urge said material to move across the uppermost hearth with a circumferential flow component, to cause said material to flow across the entire area of said uppermost hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said uppermost hearth and down its respective drop hole to the next lower hearth, and withdrawing said material from the bottom of said furnace.

Claim 41

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, rabbling with a plurality of rabble teeth depending from the rabble arms in the uppermost hearth in a critical zone through said material to be processed and urging said material to move across said uppermost hearth with a radial flow component, while simultaneously urging said material to move across said uppermost hearth with an independent circumferential flow component, to cause said material to flow across the entire area of said uppermost hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said uppermost hearth and down its respective drop hole to the nExt lower hearth, and withdrawing said material from the bottom of said furnace.

Claim 42

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, said method comprising the steps of introducing said material at the top of said furnace, rabbling with a plurality of rabble teeth depending from the rabble arms in the uppermost hearth in a critical zone through said material to be processed and urging said material to move across said uppermost hearth with a radial flow component, while simultaneously urging said material to move across said uppermost hearth with an independent circumferential flow component, to cause said material to flow across the entire area of said uppermost hearth in a distributed manner toward its associated drop hole, and successively passing said material across each hearth below said uppermost hearth and down its respective drop hole to the nExt lower hearth, and withdrawing said material from the bottom of said furnace.

Claim 43

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, a plurality of rabble teeth extending downwardly from said rabble arms nearly to the hearth floor, said rabble teeth being inclined with respect to the longitudinal axis of their respective rabble arms, elongated bar-like members carried by said rabble teeth and extending substantially parallel to the longitudinal axis of the rabble arms respectively, said method comprising the steps of introducing said material at the top of said furnace, moving said material across the entire area of the uppermost of said hearths in a distributed manner while providing the radial flow component by the inclination of the rabble teeth with respect to the longitudinal axis of their respective rabble arms, and while providing the circumferential flow component by said bar-like members, and dropping said material down through said drop hole onto the next lower hearth.

Claim 44

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths, a rotatable center shaft extending up through the center of the furnace and passing through each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, a plurality of rabble teeth extending downwardly from said rabble arms nearly to the hearth floor, said rabble teeth being inclined with respect to the longitudinal axis of their respective rabble arms, elongated bar-like members carried by said rabble teeth and extending substantially parallel to the longitudinal axis of the rabble arms respectively, said method comprising the steps of introducing said material at the top of said furnace, moving said material across the entire area of the uppermost of said hearths in a distributed manner while providing the radial flow component by the inclination of the rabble teeth with respect to the longitudinal axis of their respective rabble arms, and while providing the circumferential flow component by said bar-like members, and dropping said material down through said drop hole onto the next lower hearth.

Claim 46

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths a rotatable center shaft extending up through the center of the hearths and passing through each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, a plurality of rabble teeth extending downwardly from alternate rabble arms nearly to the hearth floor, said rabble teeth being inclined with respect to the longitudinal axis of their respective rabble arms, rabble teeth extending downwardly from the other of said rabble arms nearly to the hearth floor and being disposed substantially parallel with respect to the longitudinal axis of their respective rabble arms, said method comprising the steps of introducing said material at the top of said furnace, moving said material across the uppermost of said hearths towards its drop hole while providing the radial flow component of said material by the inclination of the rabble teeth on said alternate rabble arms with respect to the longitudinal axis of their respective rabble arms and while providing the circumferential flow component of said material by the material contact area of the rabble teeth carried by said other rabble arms.

Claim 47

A method of processing material in a multiple hearth furnace having a plurality of vertically spaced hearths a rotatable center shaft extending up through the center of the hearths and passing through each hearth, alternate hearths having drop holes disposed towards the center shaft and the other hearths having drop holes disposed towards the outer periphery thereof, a plurality of spaced rabble arms secured to the center shaft and extending radially outwardly over each hearth, a plurality of rabble teeth extending downwardly from alternate rabble arms nearly to the hearth floor, said rabble teeth being inclined with respect to the longitudinal axis of their respective rabble arms, rabble teeth extending downwardly from the other of said rabble arms nearly to the hearth floor and being disposed substantially parallel with respect to the longitudinal axis of their respective rabble arms, said method comprising the steps of introducing said material at the top of said furnace, moving said material across the uppermost of said hearths towards its drop hole while providing the radial flow component of said material by the inclination of the rabble teeth on said alternate rabble arms with respect to the longitudinal axis of their respective rabble arms and while providing the circumferential flow component of said material by the material contact area of the rabble teeth carried by said other rabble arms.