Apparatus and method for diagnosing deterioration of smokestack

Claim 1

An apparatus for diagnosing deterioration of a steel-reinforced concrete smokestack by detecting a defect in the concrete of said smokestack, comprising: thermal graphic means for producing a diagram of outside surface temperature distribution of said smokestack from an infrared ray photograph; detecting means for detecting a defect as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot; means for calculating smoke temperature in the smokestack at the defect based upon the temperature difference between the inside and outside of the smokestack at the defect based in turn on the smoke temperature at the inlet of the smokestack and said outside surface temperature distribution; means for calculating the depth of said defect based upon said temperature difference and the temperature gradient of the wall of said smokestack; a means for empirically determining a concrete crack width W based on said defect depth; and means for assessing deterioration of strength of the smokestack based on the concrete crack width W and the area of the defect as measured on said diagram.

Claim 2

An apparatus for diagnosing deterioration of a steel-reinforced concrete smokestack by detecting a defect in the concrete of said smokestack, comprising: thermal graphic means for producing a diagram of outside surface temperature distribution of said smokestack from an infrared ray photograph; detecting means for detecting a defect as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot; means for calculating smoke temperature in the smokestack at the defect based upon the temperature difference between the inside and outside of the smokestack at the defect based in turn on the smoke temperature at the inlet of the smokestack and said outside surface temperature distribution; means for calculating the depth of said defect based upon said temperature difference and the temperature gradient of the wall of said smokestack; a means for empirically determining a concrete crack width W based on said defect depth; and means for assessing deterioration of strength of the smokestack based on the concrete crack width W and the area of the defect as measured on said diagram.

Claim 3

An apparatus for diagnosing deterioration of a steel-reinforced concrete (SRC) smokestack by detecting a defect in concrete of said smokestack, comprising a thermographic means for producing a diagram of outside surface temperature distribution of said SRC smokestack from an infrared ray photograph thereof, a means for detecting a defect (F) as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot, a means for calculating smoke temperature θ g in the smokestack at the defect by an equation θ.sub.2 =θ.sub.o +(K/α.sub.2 r.sub.2) (θ.sub.g -θ.sub.o) (l/k)=(1/α.sub.1 r.sub.1)+(1/α.sub.2 r.sub.2)+(1/λ)1n(r.sub.2 /r.sub.1) wherein, r 1 : smokestack inside radius (m) r 2 : smokestack outside radius (m) θ.sub. : smokestack outside surface temperature on said diagram at said area surrounding the spot with discontinuous temperature θ f : smoke temperature (°C.) θ o : outside air temperature (°C.) α 1 : inside surface coefficient of heat transfer α 2 : outside surface coefficient of heat transfer λ: coefficient of heat transfer concrete K: coefficient of overall heat transmission, a means for calculating depth (d) of the defect (F) by an equation θ.sub.f =θ.sub.o {K/α.sub.2 (r.sub.2 -d)}(θ.sub.g θ.sub.o) wherein, θ f : smokestack outside surface temperature on said diagram at said discontinuously different spot, a means for empirically determining a concrete crack width (W) based on said defect depth d, and a means for assessing deterioration of strength of the smokestack based on the concrete crack width (W) and area of the defect as measured on said diagram.

Claim 4

An apparatus for diagnosing deterioration of a steel-reinforced concrete (SRC) smokestack by detecting a defect in concrete of said smokestack, comprising a thermographic means for producing a diagram of outside surface temperature distribution of said SRC smokestack from an infrared ray photograph thereof, a means for detecting a defect (F) as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot, a means for calculating smoke temperature θ g in the smokestack at the defect by an equation θ.sub.2 =θ.sub.o +(K/α.sub.2 r.sub.2) (θ.sub.g -θ.sub.o) (l/k)=(1/α.sub.1 r.sub.1)+(1/α.sub.2 r.sub.2)+(1/λ)1n(r.sub.2 /r.sub.1) wherein, r 1 : smokestack inside radius (m) r 2 : smokestack outside radius (m) θ.sub. : smokestack outside surface temperature on said diagram at said area surrounding the spot with discontinuous temperature θ f : smoke temperature (°C.) θ o : outside air temperature (°C.) α 1 : inside surface coefficient of heat transfer α 2 : outside surface coefficient of heat transfer λ: coefficient of heat transfer concrete K: coefficient of overall heat transmission, a means for calculating depth (d) of the defect (F) by an equation θ.sub.f =θ.sub.o {K/α.sub.2 (r.sub.2 -d)}(θ.sub.g θ.sub.o) wherein, θ f : smokestack outside surface temperature on said diagram at said discontinuously different spot, a means for empirically determining a concrete crack width (W) based on said defect depth d, and a means for assessing deterioration of strength of the smokestack based on the concrete crack width (W) and area of the defect as measured on said diagram.

Claim 6

A method of deterioration diagnosis for a steel-reinforced concrete (SRC) smokestack by detecting a defect in concrete of said smokestack, comprising steps of producing a diagram of outside surface temperature distribution of said SRC smokestack from an infrared ray photograph thereof, identifying a defect singular as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot, calculating smoke temperature θ g in the smokestack at the defect (F) by an equation θ.sub.2 =θ.sub.o +(K/α.sub.2 r.sub.2)(θ.sub.g -θ.sub.o) (l/K)=(1/αhd 1r.sub.1)+(1/α.sub.2 r.sub.2)+(1/λ)1n(r.sub.2 /r.sub.1) wherein, r 1 : smokestack inside radius (m) r 2 : smokestack outside radius (m) θ 2 : smokestack outside surface temperature on said diagram at said are surrounding the spot with discontinous temperature θ g : smoke temperature (°C.) θ o : outside air temperature (°C.) α 1 : inside surface coefficient of heat transfer α 2 : outside surface coefficient of heat transfer λ: coefficient of heat transfer of concrete K: coefficient of overall heat transmission, calculating depth d of the defect F by an equation θ.sub.f =θ.sub.o +{K/α.sub.2 (r.sub.2 -d)}(θ.sub.g -θ.sub.o) wherein, θ f : smokestack outside surface temperature on said diagram at said discontinuously different spot, empirically determining a concrete crack width (W) based on said defect depth d, and assessing deterioration of strength of the smokestack based on the concrete crack width (W) and area of the defect as measured on said diagram.

Claim 7

A method of deterioration diagnosis for a steel-reinforced concrete (SRC) smokestack by detecting a defect in concrete of said smokestack, comprising steps of producing a diagram of outside surface temperature distribution of said SRC smokestack from an infrared ray photograph thereof, identifying a defect singular as a spot in said diagram whose temperature discontinuously differs from that of area surrounding the spot, calculating smoke temperature θ g in the smokestack at the defect (F) by an equation θ.sub.2 =θ.sub.o +(K/α.sub.2 r.sub.2)(θ.sub.g -θ.sub.o) (l/K)=(1/αhd 1r.sub.1)+(1/α.sub.2 r.sub.2)+(1/λ)1n(r.sub.2 /r.sub.1) wherein, r 1 : smokestack inside radius (m) r 2 : smokestack outside radius (m) θ 2 : smokestack outside surface temperature on said diagram at said are surrounding the spot with discontinous temperature θ g : smoke temperature (°C.) θ o : outside air temperature (°C.) α 1 : inside surface coefficient of heat transfer α 2 : outside surface coefficient of heat transfer λ: coefficient of heat transfer of concrete K: coefficient of overall heat transmission, calculating depth d of the defect F by an equation θ.sub.f =θ.sub.o +{K/α.sub.2 (r.sub.2 -d)}(θ.sub.g -θ.sub.o) wherein, θ f : smokestack outside surface temperature on said diagram at said discontinuously different spot, empirically determining a concrete crack width (W) based on said defect depth d, and assessing deterioration of strength of the smokestack based on the concrete crack width (W) and area of the defect as measured on said diagram.