Monitoring of a line system

Abstract

Monitoring of a line system (1) in which a liquid medium (3) is guided in a line (2). The current pressure of the liquid medium (3) in the line (2) and in the associated current flow are sensed at sensing times. The two values are fed to a computing unit (5). The computing unit (5) calculates a theoretical flow of the liquid medium (3) in the line (2) from the sensed current pressure by taking into account a specified flow function. The flow function describes a physical relationship between the theoretical flow of the liquid medium (3) and the current pressure of the liquid medium (3). The computing unit (5) determines an individual degree of clogging on the basis of the current flow and the theoretical flow. On the basis of a number of determined individual degrees of clogging and by using stochastic methods, the computing unit (5) calculates an interval within which a degree of clogging of the line system (1) lies with a probability to be defined. The line system (1) is monitored by using the size of the interval and/or the position of the interval with respect to first limits for the degree of clogging that are defined beforehand.

Claims

1. A method for monitoring a line system, wherein a liquid medium is guided in at least one line of the line system; the method comprising: a) sensing the current pressure of the liquid medium in the at least one line and sensing the associated current flow of the liquid in the at least one line; b) receiving the sensed current pressure and the sensed current flow by a computing unit; c) calculating by the computing unit a respective theoretical flow of the liquid medium in the at least one line from the respective sensed current pressure including taking into account a prespecified flow function describing a physical relationship between the theoretical flow of the liquid medium and the respective current pressure of the liquid medium; d) determining by the computing unit a respective individual degree of clogging of the at least one line on the basis of the respective current and the respective theoretical flow; e) calculating by the computing unit an interval within which a degree of clogging of the line system lies with a probability to be defined on the basis of a number of determined individual degrees of clogging using stochastic methods for determining with a specific probability of error the values ? (? models the degree of clogging) for which the data flows ?, theoretical flow and current flow f and f.sub.act cannot be generated by the same random process; and f) monitoring the line system by using the size of the calculated interval and/or the position of the calculated interval with respect to first limits for the degree of clogging that are defined beforehand as an indication of the presence of a fault in the line system.

2. The method as claimed in claim 1, further comprising the line system is embodied as a cooling system in a metallurgical unit, or in a continuous casting plant for the production of a metallic strand, or in a rolling mill for production of a metal strip; and guiding the liquid medium by the at least one line to a nozzle, applying the liquid medium by the nozzle to the metallic strand or to the metal strip.

3. The method as claimed in claim 2, wherein the liquid medium guided to the nozzle is water.

4. The method of claim 2, wherein the monitoring of the line system is performed during a standstill of the continuous casting plant or of the rolling mill.

5. The method as claimed in claim 1, wherein the sensing times have a uniform time interval between one another lying between 2 seconds and 5 seconds.

6. The method as claimed in claim 1, wherein the stochastic methods include a one-sample t-test.

7. The method as claimed in claim 1, further comprising specifying the probability to be defined to the computing unit by an operator.

8. The method as claimed in claim 1, further comprising issuing by the computing unit an indication of a fault in the line system when the calculated interval for the degree of clogging lies completely outside the defined limits for the degree of clogging.

9. The method as claimed in claim 1, further comprising issuing by the computing unit an alarm indicating that the line system is indeterminable when the calculated interval is greater than a predetermined second limit.

10. A computer program product comprising: a non-transitory computer-readable storage medium; and a computer program product comprising a machine code and stored on the storage medium, and the code can be executed by a computing unit, wherein the execution of the machine code by the computing unit causes the computing unit to carry out a method with steps b) to e) in claim 1.

11. A computing unit having a computer program product programmed with a computer program as claimed in claim 10.

12. A device, for monitoring a line system, comprising: a) a line system having at least one line in which a liquid medium can be guided; and b) at least one apparatus for determining the current pressure of the liquid medium in the at least one line and the current flow of the liquid medium in the at least one line and a computer program product of claim 10, coupled to the apparatus.

13. The device as claimed in claim 12, further comprising a monitoring unit for monitoring the line system by using the size of the calculated interval and/or the position of the calculated interval with respect to first limits for the degree of clogging that are defined beforehand as an indication of the presence of a fault in the line system.

14. A computer program product comprising: a non-transitory computer-readable storage medium; and a computer program product comprising a machine code and stored on the storage medium, and the code can be executed by a computing unit, wherein the execution of the machine code by the computing unit causes the computing unit to carry out a method with steps b) to f) in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a method according to the invention and a device according to the invention for monitoring a line system and

(2) FIG. 2 a relationship between the current flow and the current pressure of a liquid medium of a line system and a data fit.

DESCRIPTION OF AN EMBODIMENT

(3) In FIG. 1, a liquid medium 3 is guided in a line 2 of the line system 1, wherein the liquid medium is water.

(4) In a first step, an apparatus 8 for determining a current pressure of the liquid medium 3 in the line 2 and an apparatus 9 for determining the current flow of the liquid medium 3 in the line 2 determine the current pressure of the liquid medium 3 and the current flow of the liquid medium 3 in the line 2 as parameters.

(5) In a second step, the sensed values are sent to a computing unit 5 connected to the apparatuses 8, 9. This receives the sensed values. In a third step, the computing unit 5 calculates a theoretical flow of the liquid medium 3 in the at least one line 2 on the basis of the sensed pressure taking into account a prespecified flow function. The flow function describes a physical relationship between the theoretical flow of the liquid medium 3 and the current pressure of the liquid medium 3. Furthermore, in a fourth step, an individual degree of clogging is determined on the basis of the theoretical flow and the current flow. In this context, in particular the quotient between the current and the theoretical flow is determined.

(6) Then, in a fifth step, the computing unit 5 calculates an interval within which a degree of clogging of the line system lies with a probability to be defined on the basis of a number of determined individual degrees of clogging using stochastic methods. The stochastic methods can in particular include a one-sample t-test. The probability to be defined can be specified to the computing unit 5 by an operator. The probability is freely selectable. As a rule, the probability is set to at least 90%, preferably to at least 95%.

(7) In a sixth and final step, the line system 1 is monitored by using the position of the calculated interval with respect to first limits for the degree of clogging that are defined beforehand. The position of the calculated interval serves as an indication of the presence of a fault in the line system 1. The same applies to the size of the calculated interval.

(8) Steps 1 to 6 are performed at cyclic intervals time intervals, wherein the time intervals are between 2 seconds and 5 seconds, preferably 3 seconds.

(9) If the calculated interval for the degree of clogging lies outside the defined first limits for the degree of clogging, an alarm apparatus 13 coupled to the computing unit 5 issues an alarm as an indication of the fault in the line system 1.

(10) FIG. 1 shows the line system 1 as a cooling system of a continuous casting plant for the production of a metallic strand 6. Here, the liquid medium 3 guided by means of the line 2 to a nozzle 7 is applied by means of the nozzle 7 to the metallic strand 6, in particular to a steel strand. The monitoring of the line system 1 is also performed during a standstill of the continuous casting plant.

(11) The mode of operation of the computing unit 5 is determined by a computer program 14 which runs in the computing unit 5. The computer program 14 is located on a computer-readable storage medium 15.

(12) FIG. 2 shows a relationship between the current flow f.sub.act and the current pressure w.sub.p of the liquid medium 3 of the line system 1 and a data fit 16. The current pressure w.sub.p of the liquid medium 3, to be specific the water pressure, is plotted on the abscissa. The following are depicted on the ordinate in dependence on the current pressure w.sub.p: the current flow f.sub.act of the liquid medium 3, specifically the current water flow, which was determined in the line 2 of the actual line system 1depicted by small dots 4, the current flow f.sub.act of the liquid medium 3, specifically the current water flow, which was determined in the line 2 of the line system 1 of a test arrangement in which the physical relationships of the actual line system 1 or the at least one line 2 are reflected-depicted by large dots 10 and the theoretical flow f of the liquid medium 3, specifically the theoretical water flow, which in FIG. 2 was determined as a data fit 16 of the values for the current flow f.sub.act of the liquid medium 3 in the line 2 of the actual line system 1. The data fit 16 could also be determined in the same way from the test arrangement. The theoretical flow f represents the flow function, i.e. the relationship between the current pressure w.sub.p of the liquid medium 3 and the current flow f.sub.act of the liquid medium 3. The flow function is stored in the computing unit 5.

(13) The present invention has numerous advantages. In particular, it is possible to determine the degree of clogging in a highly precise and reliable manner.

(14) Although the invention was illustrated and described in detail by the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.

LIST OF REFERENCE NUMBERS

(15) 1 Line system 2 Line 3 Liquid medium 4 Small dots 5 Computing unit 6 Metallic strand 7 Nozzle 8 Apparatus for determining the current pressure of the liquid medium 9 Apparatus for determining the current flow of the liquid medium 10 Large dots 11 Flow function 12 Monitoring unit 13 Alarm apparatus 14 Computer program 15 Computer-readable storage medium 16 Data fit