RO130005A2 - System for monitoring, detection and localization of breaks in hydraulically-long pipes - Google Patents

Abstract

The invention relates to a system for monitoring, detection and localization of breaks in hydraulically-long pipes, meant to be used in any section of pipe conveying pressurized liquids. According to the invention, the system comprises some pressure transducers and some flow-rate transducers which are installed at the two ends of the pipe section to be monitored.

Description

SYSTEM FOR MONITORING, DETECTION AND LOCATION OF THE SPREADS IN

LONG CONDUCT OF CONDUCT FROM HYDRAULIC POINT οι fi /

The invention relates to a system for monitoring, detecting and locating breaks in pipes considered long from a hydraulic point of view, of fixed type, intended for use on any section of pipe on which liquids are transported under pressure.

There are known leak detection systems from pipelines or pipeline networks, both mobile, based on ultrasonic and fixed techniques. As far as is known, most are mobile and have the disadvantage that it requires a long detection time, which implies moving a team in the presumed area of the break, not knowing exactly where the break occurred, putting the system into operation in that area, detecting breakages. . Known fixed monitoring systems, based on flow and pressure measurements, existing on different networks or pipeline systems, can give quasi-instantaneous information on the occurrence of a major accident, namely the breakage of a pipeline, but it has the disadvantage that they cannot provide accurate location information. in which it has cracked on the section of pipe on which it is mounted.

The technical problem solved by the invention consists in the continuous monitoring of the values of pressures and flows on the sections of the pressure pipes, the detection and localization of near-instantaneous breaks in the sections on which the system is mounted, all this information being provided in real time, being by a major importance especially in the industrial systems of liquid transport, respectively the forced pipes of the hydroelectric plants, pressurized additions and sections of the cooling circuits of the industrial installations, but also in the case of other major systems of transport of the liquid pressurization, respectively water supply , the secondary circuit of the heating systems. In this sense, the system allows both the reduction of the reaction time for limiting the negative effects in the event of a major accident on the pipe sections considered by detecting its occurrence in real time, as well as reducing the time to remedy such damage by determining relatively accurate of the location of the damage.

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In contrast to the existing systems, the system for monitoring, detecting and locating the breaks in the hydraulically considered long pipes performs both the detection and the almost instantaneous localization of the breaks on the sections of the pressure pipes. Through the proposed technical solution, the system eliminates the known disadvantages of the other systems in the field, by allowing both the reduction of reaction time for limiting the negative effects in the event of a major accident on the sections of pipe considered by detecting in real time its occurrence, as well as reducing the time to remedy such damage by determining the exact location of the damage.

The system for monitoring, detecting and locating breaks in pipes considered to be hydraulically long, according to the invention, has the following advantages:

it is fixed so that once mounted on the respective section it realizes the permanent monitoring of the values of pressures and flows related to the section on which it is mounted;

it is intended for use on any section of pipeline on which liquids are transported under pressure;

realizes both the detection and the localization of the almost instantaneous breakages on the sections of the pipes under pressure;

the information provided by the system is in real time;

the use of the system is of major importance especially in the industrial systems of liquid transport, respectively in the case of the forced pipes of the hydroelectric plants, the pressure additions and the sections of the circuits of the cooling circuits of the industrial installations, as well as in the case of other major systems of transport of the liquid pressesure, respectively water supply, the secondary circuit of the heating systems;

allows both the reduction of reaction time to limit the negative effects in the event of a major accident on the sections of the pipeline considered by detecting its occurrence in real time, as well as reducing the time to remedy such damage by determining the exact location of the damage.

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An example of embodiment of the invention is given below, in connection with FIG. 1, which represents:

FIG. 1 longitudinal view of the pipe section on which liquids are transported under pressure, long from the hydraulic point of view, on which is mounted the system of monitoring, detection and location of breaks.

The system for monitoring, detecting and locating the breaks on sections of pipelines considered hydraulically long involves the following steps: installation of pressure and flow transducers at the two ends, respectively upstream the inlet section (s) and downstream - the outlet section (e), of the section on which the system was fitted; (Z) represents the quota at which the entrance section is located, respectively (Day) and the quota at which the exit section is located (Ze); (P) represents the pressure in the considered section, respectively (Pi) in the inlet section and (Pe) in the outlet section; (Q) represents the volume flow through the pipeline; achievement of the system of acquisition and transmission of the measured data; the realization of the software for processing and comparing the measured data in real time; calibration of the system by carrying out measurements in permanent flow regime.

For a portion of pipe of constant diameter, considered long from the hydraulic point of view, in which the local losses of load and the kinetic terms in the law of energies can be neglected, with a permanent flow, which can be considered as rugged from the hydraulic point of view, between the input section (s) and the output section (s), the law of energies can be written in the form:

Pg ^and pg

Ci) where: z represents the dimension at which the section is located, p represents the pressure in the section considered, g represents the gravitational acceleration, _p represents the density of the fluid considered, M represents the modulus of resistance of the pipe and represents the volume flow passing through the pipe.

The modulus of resistance of the pipe is calculated exactly by the formula:

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where: D represents the diameter of the pipe, L represents the length of the pipe, λ represents the loss coefficient evenly distributed by the load and

represents the sum of the coefficients of local loss of pregnancy.

If at a distance x from the upstream section of the pipe, denoted by index i, a break occurs, the flow in the output section will become smaller than that in the input section. The lost debt can be calculated as the difference of these two debts: Op = Qi -Qe (3)

Noting the average piezometric height of a section with Hp = z + J—, the law of pg of energies becomes:

Hp, - Hp _e = ΔΗρ = MO ¹ [4]

Using this formula (4) a set of pressure measurements - considering the known level difference between the two sections - carried out permanently at different flow rates, allows the exact determination of the modulus of resistance of the pipe, for example using the most small squares, with relation:

(5) where the sum according to index j represents the sum of the measured values.

In case of a break in the pipe considered, located at a distance x from the upstream head of the pipe, the relation of energies becomes:

Hp, -Hp _e = y-xO; ₊ ~ {L - χ) θ; (6)

From this equation of the first degree in x (6) can be calculated the distance at which there is a break from the upstream section if the values of pressures and flows in the two sections and the resistance modulus of the pipe section are known. The calculation is approximate both due to the simplifications made by hypotheses, as well as due to the accuracy of the measuring devices used. It is necessary that all other sizes which

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In order to determine the existence and with a good approximation of the location of a break, two flowmeters and two pressure transducers located in the two considered sections are required, respectively in the inlet area (s) and in the outlet area (in the permanent flow regime). e).

Claims (1)

Claim System for monitoring, detecting and locating breaks in pipes considered long from a hydraulic point of view, of fixed type, intended for use on any section of pipeline on which liquids are transported under pressure, characterized in that it allows the signaling, detection and localization of quasi-instantaneous of a major defect, breakage, by measuring the values of pressures and flows at the two ends of the section on which the system was mounted.