Method for determining a radiation measurement for thermal radiation, arc furnace, a signal processing device programme code and storage medium for carrying out said method
View Patent ↗In a method, a variable characterising an operational state of an electrode of an arc furnace can be determined. An electrode flow guided to the electrode is detected in the method and the structure-borne noise oscillations are detected. From the detected electrode flow, a flow evaluation signal associated with the frequency range of the detected electrode flow is determined. From the detected structure-borne noise oscillations, an oscillation evaluation signal that is associated with a frequency range of the detected structure-borne noise oscillations is detected and a quotient from the oscillation evaluation signal and the flow evaluation signal is formed as a radiation measurement for at least one frequency common to the detected electrode flow and the detected structure-borne noise oscillation.
1. A method for determining a radiation measure for thermal radiation which originates from an arc and strikes a boundary of the arc furnace, using a signal processor, wherein the arc burns between an electrode and a material to be melted, comprising:
detecting an electrode current which is supplied to the electrode,
detecting structure-borne sound oscillations of the arc furnace,
determining with the signal processor a current evaluation signal, which is associated with a frequency range of the detected electrode current, based at least in part on the detected electrode current,
determining with the signal processor an oscillation evaluation signal which is associated with a frequency range of the detected structure-borne sound oscillations, based at least in part on the detected structure-borne sound oscillations, and
calculating with the signal processor a quotient of the oscillation evaluation signal and current evaluation signal as a radiation measure for at least one frequency which is common to the detected electrode current and the detected structure-borne sound oscillations.
2. The method according to claim 1 , wherein
a sum of quotients which are formed for a plurality of common frequencies, is formed as the radiation measure.
3. The method according to claim 2 , wherein at least one of the plurality of common frequencies is selected from the group which consists of the multiples of twice the operating frequency of the electrode.
4. The method according to claim 1 , wherein the frequency-dependent current evaluation signal is based on
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈω
t
ⅆ
t
or on
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
where n is a parameter, nε1, 2, 3, . . .
where i: imaginary unit
where e: Euler's number
where t: time
where ω: angular frequency of the electrode current
where I(t): time-dependent, detected electrode current
where I(w): frequency-dependent electrode current
where a: start of the integration interval
where b: end of the integration interval.
5. The method according to claim 4 , wherein n for
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈω
t
ⅆ
t
is selected to be equal to two.
6. The method according to claim 1 , wherein n for
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
is selected to be equal to one.
7. The method according to claim 1 , wherein the frequency-dependent current evaluation signal is formed as the frequency-dependent absolute magnitude |I n (ω)|√{square root over (I n (ω)·I n (ω))}{square root over (I n (ω)·I n (ω))}* of the function I n (ω).
8. The method according to claim 1 , wherein the frequency-dependent oscillation evaluation signal is formed as the frequency-dependent absolute magnitude |K n (ω)|√{square root over (K n (ω)·K n (ω))}{square root over (K n (ω)·K n (ω))}* of the function:
K
n
(
ω
)
∝
∫
a
b
K
(
t
)
n
ⅇ
-
ⅈω
t
ⅆ
t
where n is a parameter, nε1, 2, 3, . . .
where i: imaginary unit
where e: Euler's number
where t: time
where ω: angular frequency of the detected structure-borne sound oscillations
where K(t): time-dependent, detected structure-borne sound signal
where K(ω): frequency-dependent structure-borne sound signal
where K(ω)*: complex-conjugate structure-borne sound signal relating to K(ω)
where a: start of the integration interval
where b: end of the integration interval.
9. The method according to claim 1 , wherein the radiation measure is used for at least one of: controlling and regulating a process variable of the arc furnace.
10. A signal processing device for an arc furnace, having a machine-legible program code which has control commands which cause the signal processing device to:
detect an electrode current which is supplied to an electrode,
detect structure-borne sound oscillations of the arc furnace,
determine a current evaluation signal, which is associated with a frequency range of the detected electrode current, from the detected electrode current,
determine an oscillation evaluation signal which is associated with a frequency range of the detected structure-borne sound oscillations from the detected structure-borne sound oscillations, and
form a quotient of the oscillation evaluation signal and current evaluation signal as a radiation measure for at least one frequency which is common to the detected electrode current and the detected structure-borne sound oscillations.
11. A non-transitory computer readable storage medium containing computer instructions stored therein for causing a computer processor to:
detect an electrode current which is supplied to the electrode,
detect structure-borne sound oscillations of the arc furnace,
determine a current evaluation signal, which is associated with a frequency range of the detected electrode current, from the detected electrode current,
determine an oscillation evaluation signal which is associated with a frequency range of the detected structure-borne sound oscillations from the detected structure-borne sound oscillations, and
form a quotient of the oscillation evaluation signal and current evaluation signal as a radiation measure for at least one frequency which is common to the detected electrode current and the detected structure-borne sound oscillations.
12. The storage medium according to claim 11 , wherein
a sum of quotients which are formed for a plurality of common frequencies, is formed as the radiation measure.
13. An arc furnace comprising at least one electrode, having an electrode current detection device for detecting an electrode current which is supplied to the at least one electrode, having structure-borne sound sensors for detecting structure-borne sound in a boundary of the arc furnace, and having a signal processing device according to claim 10 , wherein the electrode current detection device and the structure-borne sound sensors are operatively connected to the signal processing device.
14. The arc furnace according to claim 13 ,
wherein the signal processing device is operatively connected to at least one of a control and a regulating device for determining a manipulated variable for a process variable of the arc furnace from the radiation measure.
15. The arc furnace according to claim 13 , wherein
the signal processing device forms a sum of quotients which are formed for a plurality of common frequencies as the radiation measure.
16. The arc furnace according to claim 15 , wherein at least one of the plurality of common frequencies is selected from the group which consists of the multiples of twice the operating frequency of the electrode.
17. The arc furnace according to claim 13 , wherein the frequency-dependent current evaluation signal is based on
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
or on
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
where n is a parameter, nε1, 2, 3, . . .
where i: imaginary unit
where e: Euler's number
where t: time
where ω: angular frequency of the electrode current
where I(t): time-dependent, detected electrode current
where I(ω): frequency-dependent electrode current
where a: start of the integration interval
where b: end of the integration interval.
18. The arc furnace according to claim 17 , wherein n for
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
is selected to be equal to two.
19. The arc furnace according to claim 13 , wherein n for
I
n
(
ω
)
∝
∫
a
b
I
(
t
)
n
ⅇ
-
ⅈ
ω
t
ⅆ
t
is selected to be equal to one.
20. The arc furnace according to claim 13 , wherein the frequency-dependent current evaluation signal is formed as the frequency-dependent absolute magnitude |I n (ω)|√{square root over (I n (ω)·I n (ω))}{square root over (I n (ω)·I n (ω))}* of the function I n (ω).