DE4333095A1 - Method for detecting a leak in a drinking water supply network and arrangement for applying the method - Google Patents

Abstract

In a method for detecting a leak (29) which has occurred in a drinking water supply network (10) at one of a plurality of consumer connecting lines (21 to 24) which are connected to a main supply line (28), their external temperature is continuously measured for a sufficiently long time span of, for example, one day, and is recorded, so that for each of the consumer connecting lines permissible maximum and minimum values can be determined between which the line temperature varies on the basis of the removal of water. If the magnitude of the temperature difference between the extreme temperatures determined in this way on one or more of the monitored consumer connecting lines (21 to 24) is significantly smaller than on the other consumer connecting lines, this is then a reliable index of the fact that the consumer connecting line or lines which is or are affected by the lower temperature dynamics has or have a leak. <IMAGE>

Description

The invention relates to a method for recognizing egg leak in a drinking water supply network, where several consumer connecting lines and main lines connected to a main supply line are on one of the consumer connection lines occurs, as well as one for the application of the method suitable measuring arrangement.

Early detection of leaks in drinking water water supply networks for various reasons such as B. corrosion caused by road traffic Vibrations and loads, seasonal te temperature fluctuations and others more or less occur inevitably and also by the most careful Long-term approach to laying such networks is not are avoidable, is becoming increasingly important as the Providing drinking water of sufficient quality and in sufficient quantities increasingly more complex and therefore is also becoming more expensive. For economical operation it is therefore independent of a water supply company inevitable, the water losses that come in good approximation the measurable amount of water that is fed into the network and the also measured amounts of water, the taken from the network, can be determined, if possible  to keep low. Individual leaks can be caused by such However, measurements are not recognized, but all if the general condition of the network as a whole, then that such a network is also permanent with regard to the Occurrence of individual leaks must be checked if there is Long-term acceptable water loss should be kept.

To detect leaks in this regard often used acoustic methods that ba sier that at leaks at which under relatively high Pressurized water flows out, characteristic ge Noises arise, both from the pipeline as structure-borne noise as well as in water as water noise Spread along the pipeline and z. B. to access Lichen places of the pipe can be listened to where in addition to conventional listening boxes and / or pipes also electro-acoustic devices such as geophones, ground microphones phones with electro-acoustic amplifiers come, which is also a record of the noise signals enable and to this extent facilitate their interpretation tern. It is also for leak detection and location knows to include so-called electroacoustic correlators put that based on leak-characteristic noise signals the detection of a leak and based on run timelines allow the location of a leak chen.

The sensitivity of such acoustic detection ver driving is limited in many ways, however  one in that numerous sources of noise are excluded at any time of the day can be, on the other hand, that plastic tube re that predominantly as consumer connecting lines are used, with a high damping are, so that a formwork cable only over short lines sections. With acoustic methods alone therefore a drinking water supply network is not in there can be monitored accordingly.

The "noiseless" method, a leak by closing flow measurements in closed, as small as possible parts of the network is very complex, because by itself Lockable network zones are usually still relatively large are and therefore, even if a leak is reliably fixed can be difficult to locate remains because inflow measurements have no indication about it can give which pipe within the cordoned off Subzone is leaking. Other special procedures leading to in addition to detecting a leak, there is also a allow approaching localization of the same, e.g. B. a Color test by coloring the water or the application the tracer gas technique, d. H. Detection of a leak with tels of a water-soluble test gas, which over the Leak into the surrounding soil and through diffuse it quickly to the surface and there by means of a flame ionization detector sen, are in turn with the disadvantage tet that at least parts of the network are out of order have to be taken.

The object of the invention is therefore to provide a method for Leak detection in drinking water supply networks ben, the reliable detection relatively small ner leaks allows that without disturbing the water Ver care operation can be used and also a new one term reference to that consumer connection pipe mediated, at which the procedurally recognized leak is available, as well as a measuring arrangement to create fen, the automated execution of the procedure rens enables.

This task is carried out with regard to the process that Basic idea by the features of the patent claim 1 and in embodiments of this method by the features of claims 2 to 8 and with regard possible, technically easy to implement meas orders by the features of claims 9 to 16 ge solves.

Assuming that the main supply temperature management, through which a variety of consumers is largely constant, d. H. itself al If necessary, change significantly over a few days can and a very accurate measure of the temperature of the in of the main supply line practically constantly flow the water is that further the earth in that Depth at which the main supply line and that of this consumption leading to individual consumers cher connection lines run, also one in  explained meaning "constant" temperature, which is usually by a few degrees, e.g. B. 2 to 3 ° C from the Main supply line temperature differs, and that the temperature is considered a broken one coming consumer connecting line after over no water has been drawn for a long time, has assumed a stationary value, equality the temperatures on the outside of this consumer Connecting pipe and in the directly on this corresponds to the "boundary layer" of the soil - According to the invention - in a first process step continuously or "point by point" at defined times the time course T (t) of the outside temperature measured and registered the consumer connection pipe, which occurs during and during the water extraction following period of time that elapses until this Temperature again the stationary value, which is essentially the temperature of the adjacent soil speaks, has achieved. The meanwhile on taken - lower or higher - extreme value of Outside temperature of the consumer connection pipe nä the temperature of the main supply pipe, becomes - by forming the difference - with that of the temperature corresponding stationary temperature value of the soil compared and so - approximately - the "dynamic loading rich "determined within the given order conditions the outside temperature of the connection pipe res varies. In the same way to the other ver Going to the user connection pipes, they will be used for this characteristic dynamic ranges of the connecting pipe  Temperatures determined.

Since the temperature-dynamics-Be Leaked consumer leaked end tube is less than that of a dense Consumer connecting pipe, is from a compare the processing of for individual consumers tail pipes determined an existing dynamic range A leak can be seen and the connection pipe identifi ed where the leak occurred.

Is featured in the increasing temperature measurements went as provided according to claim 2, after which the Water is withdrawn until - under the specified boundary conditions - the temperature of the in the Main supply line of flowing water as a statio Extreme extreme temperature of the consumer connection line results and then the water withdrawal via the testing consumer connection line for so long remains until it returns to the stationary value of the Temperature has reached, which in the we considerably corresponds to the temperature of the ground, at de perfect management of a significantly different, between the temperature of the soil and the tempera temperature of the main supply line value, it is normally sufficient that this carry out measurements only once, so that after a relatively short total measuring time a reliable result is available.  

Is used for all of the different consumer Connection lines temperature / time ver run measurements the same temperature sensor applies, this need not be calibrated, provided it is guaranteed that the temperature-response behavior the sensor is not subject to fluctuations in time, what sensors corresponding to the state of the art can be assumed to a sufficient extent.

When using only a single temperature sensor for all measurements can be used for these in total the measurement time thereby as far as possible be induced that first in successive Mes solutions for water extraction via the individual ver Accessible stationary user lines Temperature values are measured and then the stationary temperature values, which are for non-removal me surrender.

Even with the associated with minimal measurement time requirement Method of carrying out the method according to claim 4 it is not necessary to calibrate temperature sensors use, however, these should be the same sensitive speed (change of the output signal per temperature unit) so that they can be determined by means of one sensor each immediately communicate temperature-dynamic ranges are comparable. At least the sensitivity should be of the individual sensors.

By a type of through corresponding to claim 5  The procedure is sufficiently accurate reached or sensitivity to detection also achieved if consumer behavior is not based on the measurements can be coordinated.

Based on additional performed according to claim 6 Temperature measurements can be seen with what sensitivity the leak detection method in the respective measurement period can be used.

On the basis of comparison data to be determined according to claim 7 can be determined to what extent the environmental conditions different measuring points differ from each other and / or change.

By a procedure corresponding to claim 8 is a minimum sensitive at any time of the year Leak detection method can be achieved.

By the features of claim 9 is its principle Liche structure in particular for a mobile Use suitable arrangement for applying the invent according to the method specified by the Merk male of claims 10 to 12 in circuit and control is technically specified, wäh rend which is special in terms of circuitry simple structure distinguished further arrangement for Implementation of the method according to the Claims 13 and 14 with regard to a fixed installation lation is designed, which is already in the creation of the  Network provided for its permanent monitoring becomes.

By means of thermal contact designed according to claim 15 blocks for their thermally highly conductive fixation the consumer connecting pipes according to claim 16 professionally designed clamping devices are suitable the temperature sensors with good thermal contact to the Connection pipes can be easily fixed on these.

The method according to the invention is particularly for Suitable water supply networks where at least two, usually four consumer connection pipes within a shaft accessible from above, in which also a hydrant is arranged to the main supply line device are connected so that the measuring points without too additional preparatory work in the shaft below can be brought.

The method according to the invention can also be used for detection a leak in a main water pipe can be exploited, as in a downstream of one Leakage section of the main supply line always a larger dynamic range ΔT of their temperature results as being located in the upstream of the leak Part of the same.

Because generally the occurrence of a leak in a water leading line - main supply and / or house final line - the dynamic range ΔT, within which  the pipe temperature as a result of water withdrawals may vary, reduced to a lower value and thereby the course of the line temperature over time can become sluggish, "smoothes" it, as it were a leak can also be recognized by the fact that at a Defined duration for a leak over a period of time affected line of the network recorded temperature Curve T (t) the number of extreme values of the tem temperature - the absolute and relative maxima and Minima - is significantly lower than with a wah same period for a dense clearing of the Network recorded temperature curve.

The method according to the invention is described below embodiments shown in the drawing its implementation of suitable measuring arrangements in white ing details explained. Show it

Figure 1 shows a part of a drinking water supply network, in which consumer connecting pipes are connected to the main supply line of the network within a walk-in shaft.

FIG. 2 shows progress curves of the outer temperatures of the consumer connection pipes of the network of Figure 1, when one of the tubes is associated with a leak, for explaining a method of the invention for leakage detection.

Fig. 3 shows a first measuring arrangement for carrying out the leak detection method in a schematically simplified block diagram representation;

. Fig. 4 is a simple device for fixing temperature sensors of the measuring arrangement of Figure 3 to the consumer-connection tubes of the network of FIG. 1;

Fig. 4a shows a special design of a heat contact block provided as a carrier egg nes the temperature sensors and

Fig. 5 shows another embodiment of a Meßan arrangement for leak detection in a representation corresponding to FIG. 3.

For the part of a total of 10 designated drinking water supply network shown in FIG. 1, it is assumed - for the purpose of explanation - that over this part of the network 10 four buildings - residential units - 11 , 12 , 13 and 14 are supplied , each of which can be shut off by means of a slide 16 , 17 , 19 or 18 lockable house connection line 21 to 24 and a connector 27 to a main supply line 28 , can be locked against this, via which a hydrant 26 to the main supply line 28 is connected, it being assumed that the hydrant 26 and the individual residential units 11 to 14 associated slider 16 to 19 including the connected to these end sections of the house connecting lines 21 to 24 in a shaft 31 , z. B. from above, are arranged accessible. It is further assumed that the house connection line 23 leading to the residential unit 13 has a schematically indicated leak 29 , via which water emerges into the surrounding earth, in which the house connection line 23 is at a depth of approximately 1.2 meters is buried.

To detect the leak 29 is carried out according to a variant of a method based on temperature measurements using a single electronic temperature sensor 32 , which generates a characteristic of the measuring temperature, registerable electrical output signal, as follows, with an explanation of the procedure also to FIGS. 2 reference is made.

First, for defined measuring time periods T _M21 , T _M24 , T _M22 and T _M23 , - of the same duration - within which a plurality of water withdrawals via the individual house connecting lines 21 to 24 are to be expected, for each of them by the temperature curve 36 to 39 of the diagram of FIG. 2 represented T / t curve measured and registered or electronically stored in a format that can later be used.

Appropriately, after the temperature profile measurement has been carried out on the house connection line 21 as the first measurement, the temperature profile measurement is then carried out on the “opposite” house connection line 24 , which - via its assigned slide 19 - to the connection to the main supply line 28 connected to the connecting piece 27 , as well as the house line 21 monitored as he ste, which is also connected to this connecting piece 27 and thus also to the main supply line 28 via its slide 16 .

If a first - preliminary - comparison of the temperature _curve 36 and 37 carried out afterwards shows that these vary between the same extreme _values T _maxU and T _minW , this is, statistically speaking, primarily an indication that neither of the two house Leads 21 and 24 have a leak and in the second place, which is statistically far less likely that both house leads 21 and 24 have a leak with exactly the same page size.

In order to gain a decision, a third measurement is carried out, e.g. B. on the two ten, as shown in FIG. 1 left house connection line 22 , which is connected via the slide 17 and the connector 27 to the main supply line 28 , to which this and the slide 18 and the connection line 23 is connected, which leads to the further residential unit 13 on the opposite side of the street.

If the temperature profile _curve 38 , which was obtained by the third measurement, in turn varies between the same extreme _values T _maxU and T _minW , between which the temperature profile _curves 36 and 37 , which were determined by the first and second measurement, vary, then this is so there is a high probability that there is a leak at none of the house connecting lines 21 , 24 and 22 tested so far, since the probability that all of the three house connecting lines 21 , 24 and 22 already checked will occur Leak is exactly the same size, is very small.

Next, for the last of the house connection lines 23 which have not yet been checked, the temperature curve 39 resulting from this is measured for the measurement period T _M mentioned.

This measurement shows that the temperature difference δT between the maximum temperature T _maxL and the minimum temperature T _minW , between which the extreme _{values of} the temperature curve 39 vary, is less than the temperature difference ΔT, between which the maximum values T _maxU and T _{minW of} the _curves 36 , 37 and 38 vary, so this is a sure indication that the leading to the "third" residential unit 13 house connection line 23 is affected by a leak 29 .

This applies both when, as is the case in the warmer months of a year, the temperature of the water in the main supply line 28 is lower than the average temperature of the water which arises in the house connecting lines 21 to 24 when water is not withdrawn via this water, and also if, as is the case in the cooler months of the year, the temperature in the main supply line 28 is higher than the average temperature which arises in the house connection lines 21 to 24 , if above this Water is not removed.

The method explained so far leads much more quickly, namely within a single measuring period T _M to the above-mentioned result, if at the same time all of the four house connecting lines 21 to 24 have the temperature-profile curves 36 to 39 associated with water extraction within this period T _M be measured.

For a qualitative explanation of the T / t curves 36 to 39 shown in FIG. 2, it can be assumed that the soil in which the house connection lines 21 to 24 are laid has a somewhat higher temperature than that caused by the main supply line device 28 flowing water, which flows relatively quickly through the main supply line due to numerous withdrawals of water from the network 10 and therefore, until it reaches the consumer, the ambient temperature, if this significant, z. B. is 2 ° higher, can not accept. That in a single one of the house connecting lines 21 to 24 , over which water removal only takes place relatively rarely, correspondingly longer "stand", but still water has "time" to absorb heat from the environment by conduction, so that its temperature - At least approximately - can rise to the ambient temperature T _maxU . In the house connection line 21 , this temperature was reached at the time t 1 of the T / t curve 36 . A water tapping in the residential unit 11 which begins at the time t 2 and which leads to relatively warm water being drawn off via the house connecting line 21 and flowing into this colder water from the main supply line 28 has the consequence that the water temperature in the house Connection line 21 , which is monitored by means of the temperature sensor 32 , the device being taken as a measure of what the outside temperature of the house connection line 21 decreases, as represented by the first falling branch 43 of the T / t curve 36 . If a relatively large amount of water is removed, e.g. B. the filling amount of a bathtub of about 100 liters, the water temperature in the house connection line 21 drops to the given in the main supply line 28 temperature T _minW from which the lower limit of the possible water temperatures in the house connection lines 21 to 24 marked. After the end of the water withdrawal, the water temperature in the house connection line 21 rises again immediately, as represented by the first rising branch 44 of the T / t curve 36 . Takes place a little later, e.g. B. at the time t₃ again a water withdrawal, the temperature at the house connection line 21 drops again, as represented by the second falling branch 46 of the T / t curve Darge. If this water withdrawal was only marginal, then the minimum temperature T _{minW is} not reached, but _instead a temperature rise 44 ′ occurs again, which, if the next withdrawal takes place significantly later, can again lead to the maximum value T _maxU . The range of variation - dynamic range - _{.DELTA.T, within} which the temperature values measurable on the house connection line 21 can vary, is - essentially - by the ambient temperature in the ground as the upper limit value T _maxU and the water temperature in the main supply line 28 as the lower limit value T. _minW limited.

However, as assumed for the house connection line 23 of the third residential unit 13 , a leak 29 existing, through which water can continuously flow into the soil surrounding the house connection line 23 , it also arises when in the residential unit 13 a water withdrawal does not take place, as an upper limit T _maxL , which the temperature at the house connection line 23 can no longer exceed, an equilibrium temperature which lies between the water temperature T _minW in the main supply line 28 and the ambient temperature T _maxU , with the result that the dynamic range δT possible for the defective house connection line 29 is significantly smaller than the dynamic range ΔT of a dense house connection line.

The method explained so far therefore allows, without the need for absolute measurements of temperatures, based on a detection of the dynamic ranges ΔT and δT, within which in a dense house connection line 23 whose temperature or in a leaked house connection line whose temperature over several water withdrawals can vary to clearly identify the presence of a leak.

If such a leak 29 already exists before the temperature measurements could be started, then at least one comparison measurement with an undamaged house connection line 21 and / or 22 and / or 24 is required for its unambiguous identification.

In principle, such a comparison measurement can also be carried out from a relatively distant measuring point, e.g. B. in a wide shaft 31 connected to the Hauptversorgungslei device 28 house connection line.

If a temperature-monitoring temperature sensor 32 is permanently installed on a house connection line, the occurrence of a leak can be reliably detected from a change in the dynamic range from a value ΔT to a smaller value δT within a short time.

The described method is very sensitive and he leaves under a typical to be regarded as a condition that the temperature difference ΔT between the house connecting lines 21 to 24 surrounding earth and the water temperature in the main supply line is about 2 °, a clear evidence a leak with a leakage loss of only 1 m³ / day.

In order to obtain information in advance as to which detection sensitivity is to be expected for the dynamic range measuring method, is in a depth in which the house connection pipes 21 to 24 are laid and in an area which can be assumed to be there there is no leak nearby, measure the temperature of the ground, likewise at an accessible location, e.g. B. in the area of the hydrant 26, the temperature at which the main supply line 28 is located, since these temperatures are a very good approximation of the temperature T _maxU and the temperature T _minW , through which - with the house connection line intact - the dynamic range ΔT is determined, within which the tempera tures of the house connection lines 21 to 24 may vary.

As far as the same temperature sensor is used for the measurement of the temperature of the soil and the measurement of the temperature of the main supply line 28 , which is readily possible since both temperatures T _maxU and T _minW can be assumed to be largely constant at least over a day, so This temperature sensor does not even need to be calibrated, since only the detectable temperature difference ΔT is important for the sensitivity of the measuring method, the sensitivity of the measuring method explained so far the better, the greater this temperature difference ΔT.

If the leak 29 to be detected is relatively large, with the result that the temperature T _{maxL of} the leaky house connection line 23 differs only slightly from the temperature T _{minW of} the main supply line 28 , it may be sufficient for the detection of the leak 29 if the Temperatures T _maxU or T _{maxL of} the respective house connection lines 21 , 22 and 24 or 23 are each measured after a period of time within which a water withdrawal via this house connection line 21 to 24 has not occurred over a longer period of time and is therefore assumed it can be seen that the temperatures of the monitored house connection lines 21 to 24 have each assumed their stationary value T _maxU or T _maxL .

If this comparison shows that three of these temperatures, in the assumed explanatory example the temperatures of the connecting lines 21 , 22 and 24 have the same, relatively high value T _maxU and only the temperature of the connecting line 23 is significantly lower, then such a - simple - Measurement of the house connection line 23 identifiable, at which the leak 29 is present.

Such comparison measurements can also be carried out with a single, non-calibrated temperature sensor 32 if this can be implemented sufficiently quickly from measuring point to measuring point, which is at least the case when the individual house connection lines 21 to 24 , as for the explanatory example according to FIG . 1 are relatively easily accessible before exposed in the well 31st

If, on the other hand, the temperature of all four house connection lines is measured at the same time, the measuring time T _{M can} be minimized by arranging with the residents to take a defined quantity of water from their respective house connection at a certain time, which is sufficient to cover the Bring house connection lines 21 to 24 to their in good proximity with the temperature of the water in the main supply line 28 corresponding minimum temperature T _minW and then for a period of time which is sufficient to bring the temperature of the main connection lines 21 to 24 back to their respective maximum temperature T _{to let maxU} or T _maxL rise, no water to be taken.

If such an appointment cannot be reached with the residents, the leak detection method can also be carried out using longer measurement times of a few days in such a way that a temperature sensor 32 is installed on each of the house connection lines 21 to 24 and their temperature-characteristic output signals are continuous recorded or electronically stored at regular intervals and evaluated computationally after a period of time considered sufficient.

As temperature sensors 32 , temperature-sensitive semiconductor components such as NTC or PTC resistors, optionally also Zener diodes with temperature-dependent breakdown voltage are expediently used, each of which is part of an integrated circuit (IC) which outputs the output signal of the temperature-sensitive Elements processed to a temperature-characteristic output signal, which is accessible by conventional means of analog / digital conversion and thus also further processing by means of a microprocessor or an evaluation computer.

Temperature-sensitive IC's of this type are for measurement range between -50 ° C to + 150 ° C in sufficiently small NEN sizes commercially available, so that a sol cher IC, which is already cast in a plastic housing is easily in a bore of only about 8 mm Diameter of a thermal contact block used and in this by means of a curable synthetic resin, for. B. egg nes two-component polyester adhesive firmly and with the Heat conduction block itself in good thermal contact can be anchored, which in turn by spring elastic and / or tensionable clips or brackets the intended temperature measuring points, with these large located in the plant, can be fixed.

Before with reference to FIGS. 4 and 4a to details Derar term sensor holders is received, whether initially with reference to FIG. 3 illustrates an overall designated 50 measuring arrangement can be detected with the after with reference to FIGS. 1 and 2 methods explained an already-appeared leak can. It is assumed that the explanation of the function of the measuring arrangement 50 is also sufficient for its circuitry description, since a relevant trained specialist in measuring technology can realize the arrangement 50 with knowledge of its function and its purpose with common means of electronic circuit technology.

Within the scope of the measuring arrangement 50 , each of the temperature sensors 32 is assigned a measured value preparation stage, denoted overall by 51 , which has an analog / digital converter 52 , a "digital" summing stage 53 , an electronic memory 54 and a processing of the time by the temperature sensor 32 continuously Lich generated temperature measured value output signals control synchronizing stage 56 and its own, as shown in the battery 56 connected to the voltage supply source 57 comprises. The controlled by its own clock synchronizer sierstufe 56 outputs at a first control output 58 in a periodic sequence signal output control pulses for the duration of the pending temperature measurement signal on the digital output 59 of the A / D converter 52 as a bit combination Current value is held.

At a first synchronization output 61 , the synchronization stage 56 outputs synchronization pulses which are generated with the same periodicity as the signal output control pulses, but compared to this by a small period of z. B. 1/4 of the pulse duration of the signal output control pulses are delayed and in turn have a pulse duration that speaks ent about half the pulse duration of the signal output control pulses, for which the output signal at the digital output 59 of the A / D converter 52 is kept constant.

Through the synchronization pulses with which the sum mierstufe 53 is controlled, the takeover of the respective - digital - output signal of the A / D converter 52 in the summing stage 53 and its addition to the total value obtained by summing received measured value signals controlled.

After the preselected number of signal output control pulses has been given at the first synchronization output 61 , the synchronization stage 56 gives one within the period of time which elapses after the last generated signal output pulse has decayed until the next one is set second syn chronization output 62 from a memory loading pulse, through which a - serial - storage of the pending summa tion output 63 of the sum output signal of the summing stage 53 in the electronic memory 54 is triggered.

After the transfer of the output signal currently pending at the summation output 63 of the summing stage 53 to the memory 54 , the synchronization stage 56 outputs a third synchronization output 64 , still within the time period between the previously output "last" signal output control pulse Measuring time span of the duration T _SM and the first signal output control pulse of the following measuring time period T _m elapses, a reset pulse by which the summing stage 53 is reset to the value 0 at the summation output 63 .

The result of a longer examination period of two days, the content of the electronic sensors 54 individually assigned to the temperature sensors 32 is thus with a - as it were compressed - sequence of temperature value sums, which in turn are characteristic of an average temperature, which in each of the measuring periods T _SM in which the number of individual measurements for each summation cycle were made before.

In a typical configuration of the measuring arrangement 50 , the duration of the summation time periods T _{SM is} 10 minutes, so that 144 measurement values are obtained per temperature sensor 32 and day, whereby 10 individual measurements can be conveniently carried out within such a measurement time period, which are combined to form a single one , used for the later evaluation "measuring point" are compressed.

The evaluation of the temperature data contained in the memories 54 of the individual temperature sensors 32, which contain detailed information about the temperature course in the monitored house connection lines 21 to 24 , is advantageously carried out by means of an electronic computer 66 , into which the data stored at the individual measuring points are read can.

In the measurement arrangement 50 according to Fig. 3 is provided in addition to the temperatures of the service lines 21 to 24 registered temperature sensors 32, a tem perature sensor 32 can be registered with the immediately the temperature of the main supply line 28 and the time course thereof, wherein the diesbe zügliche temperature sensor 32 in the immediate vicinity of the main supply line in the casing of a hydrant 26 , for. B. an underfloor hydrant is arranged, in which it has been passed through the hose connection 68 of the hydrant.

The time tracking of the temperature of the main supply line 28 is useful if, for. B. is pumped from time to time into an elevated tank of the water supply network 10 , which has a different temperature than water still present in the elevated tank.

The measuring arrangement 50 according to Fig. 3 with the Temperatursen sensors 32 each individually associated Analag- / digital wall learning 52, summation 53, memories 54 and Synchroni sationsstufen 56 and supply voltage sources 57 is particularly suitable for a quick installation after a leak 29 occurred and must now be quickly demonstrated before z. B. based on sound correlation measurements he can follow the location of the leak.

For - temporarily - fixing the temperature sensors 32 to the house connection pipes 21 to 24, which are mostly made of plastic (PVC), more rarely made of gray cast iron, and to the main supply line 28, which is mostly made of gray cast iron and with good thermal contact with them, clamping devices 69 are suitable which, as for example in are the Fig. 4, designed as a simple screw clamps, by means of which a stable thermal contact block 72 is, for its part standing with the heat conduction block 72 in good thermal contact is inserted into the temperature sensor 32, to the outer surface of the jeweili gen house connection pipe 21 to 24 or the main supply line 28 can be pressed. Due to the self-centering design of the clamping device 69 , on the one hand, the V-shaped course of two legs 73 and 74 adjoining each other at an obtuse angle, the clamp bracket 71 , which is open on one side, viewed in cross section, together with the J-profile shape, and the radial course of the central axis 76 of the Zwin gene screw 77 is conditional, which is screw-guided on one of the two V-shaped stirrup legs 73 and 74 opposite cross leg 78 of the Zwin gene bracket 71 and with a Zen trier tip 79 engages in a centering depression 81 of the heat contact block 72 , as well whose complementary concave design of the respective tube of its contact surface 82 , with which it bears in the clamping position of the screw clamp 69 over a large area of the respective tube, on the other hand, overall a positive fixation of the thermal contact block 72 is achieved on the respective tube U.N d Because of the large area, there is also good thermal contact with the temperature sensor 32 .

The thermal contact block 72 can, as shown in Fig. 4a, have the shape of a prismatic rod or block, the usable as contact surfaces with the pipe to be monitored longitudinal surfaces 82 , 82 ', 82 ''and 82 ''' different radii of such pipes have corresponding concave curvatures. The Temperatursen sor 32 is expediently be arranged in this configuration of the thermal contact block 72 in a along the centra len axis 83 of the block 72 extending bore 84, and it is at each of the curved Längsflä chen a centering recess 81 is provided.

The further in Fig. 5, to the details of which reference is now shown, shown overall with 80 further measuring arrangement for detecting a leak 29 can be used according to the same method as the measuring arrangement 50 according to FIG. 3, is in the difference to this, however, intended as a permanently installed measuring arrangement with which a drinking water supply network is continuously monitored and leaks occurring in it can thus be detected very early on.

With reference to this measuring arrangement 80 , too, it is assumed that the explanation of its function is sufficient to enable its implementation by a person skilled in the art of measuring technology.

In the measuring arrangement 80 , in addition to the tempera ture sensors 32 , which capture the connection lines 21 to 24 prevailing at the individual house connections, a further temperature sensor 32 is provided, which measures the soil temperature at the depth to which the house connection lines are laid in the ground , and a temperature sensor 32 which detects the temperature of the main supply line 28 .

The measuring arrangement 80 is controlled by the central electronic calculator 86's, the selection of a sensor from a switching stage, in the framework of which the supply voltage source for all temperature sensors 32 is provided, whose interval, cyclical activation controls, each time only one of the sensors 32 is activated by supplying the supply voltage. The measurement signal outputs 87 of the individual temperature sensors 32 are connected via an OR operation, mediated by the sensor selection switching stage 86 , to the analog input 88 of a single analog / digital converter 52 used for all temperature sensors 32 , which converts the measurement signals to of the computer 66 brings processable digital format.

Through the selection signal by which the respective sensor 32 is addressed, a file assigned to the respective sensor is also determined in the computer in which the measured value data generated by the respective sensor is stored in the order in which they are detected become. The data compression mediated in the measuring arrangement 50 according to FIG. 3 by its summing stages 53 is achieved in the measuring arrangement 80 by computer processing of the data by means of the computer 66 .

Since, in the measurement arrangement 80 according to Fig. 5, in contrast to the measurement arrangement 50 according to Fig. 3, a parallel He version of temperatures and pre-processing of the same is not possible, reduced when it is simultaneously required that the ge by means of the measuring arrangement 80 Mäss to Fig. 5 representable temperature history curves out clearly the time resolvability of temperature fluctuations the same structure have as the means of the measuring device 50 according to 3 measurable Tem perature gradients Fig. that for detecting a temperature related time intervals measured value available to the fraction 1 / n of those measuring periods which can be used in the measuring arrangement 50 according to FIG. 3 for each sensor 32 for generating a temperature measurement value, with n being the number of temperature sensors being referred to via the single analog / digital converter 52 of the measuring arrangement 80 on the computer 66 are closed.

The accuracy of the temperature value acquisition is there not significantly influenced by because the ver remaining measuring time intervals for achieving a good signal / noise ratio long enough are.

Claims (16)

1. A method for detecting a leak that has occurred in one of the consumer connecting lines in a drinking water supply network in which several consumer (house) connecting lines are connected to a main supply line, characterized by the following procedural steps:

• a) during and / or immediately after a water withdrawal, which takes place via a consumer connection line ( 21 , 22 , 23 or 24 ) that is considered defective, its outside temperature is continuously measured by means of a temperature sensor ( 32 ) and at least the one occurring here Hold the extreme value (minimum or maximum value) and compare it with the extreme value of the temperature (maximum or minimum value), which results in a stationary value if no water is drawn from the consumer connection line for a long time;
• b) carrying out process step (a) on at least one further consumer connecting line (s) ( 21 to 24 ) branching off from the main supply line ( 28 );
• c) Comparison of the determined temperature differences.

2. The method according to claim 1, characterized in that the water withdrawals via the consumer connection lines ( 21 to 24 ), the maximum or Mi nimum temperature differences are determined, each because so long until the respective steady-state value by the Wasserent achievable extreme temperature and that the water withdrawals are stopped until the characteristic - stationary - extreme value of the respective consumer connection line is reached. 3. The method according to claim 1 or 2, characterized in that the to be carried out at different consumer connection lines to temperature / time Ver run measurements with the same temperature sensor ( 32 ) are carried out. 4. The method according to claim 1 or 2, characterized in that the temperature / time profiles to be detected to determine the extreme temperature values are measured simultaneously on all of the consumer connecting lines ( 21 to 24 ) provided for a temperature comparison. 5. The method according to any one of claims 1 to 4, characterized in that the T / t course measurements carried out on the individual consumer connecting lines ( 21 to 24 ) extend over at least one full day, and either continuous registration of the temperature ver running (T / t) on the individual consumer connection lines ( 21 to 24 ) is carried out or an intermittent registration is carried out at intervals of at most 15 minutes and since the determined temperature data are only subjected to an evaluation after completion of the measured value recordings. 6. The method according to any one of claims 1 to 5, characterized in that in addition a continuous registration of the outside temperature of the main supply line ( 28 ) and preferably also a continuous registration of the temperature of the soil takes place for the depth in which the consumer connecting lines ( 21 to 24 ) are laid in the ground. 7. The method according to any one of claims 1 to 6, characterized in that the maximum and minimum temperatures of the consumer connecting lines ( 21 to 24 ), which give rise to statistical water withdrawals, a continuous comparison with the earth's temperature and / or the temperature of the main supply line ( 28 ) are subjected. 8. The method according to claim 6, characterized in that in the event that the difference between the temperature of the main supply line ( 28 ) and the temperature of the ground is less than 0.50 and the temperature of the main supply line ( 28 ) is the higher, at least secondly, heated water is fed into the drinking water supply network ( 10 ). 9. Arrangement for using the method according to one of claims 1 to 8 with the Ver to be checked consumer connection lines each individually assigned temperature sensors, characterized in that the temperature sensors ( 32 ) are each individually assigned a measured value processing stage ( 51 ) by means of de Measurement data obtained over a larger number of measuring cycles can be stored in a format suitable for subsequent evaluation by means of an electronic computer ( 66 ). 10. The arrangement according to claim 9, characterized in that the measured value processing stages ( 51 ) each have an output signal of the temperature sensor ( 32 ) converting the digital signal into analog / digital converter ( 52 ), the output signals of the analog / digital Converter integrating processing under throwing summing stage ( 53 ), an electronic memory ( 54 ) for serial acceptance and storage of the temperature history data provided by the summing stage ( 53 ) and a synchronizing stage ( 56 ) for controlling the summation and storage operation of the Measured value processing stage ( 51 ) and its own supply voltage source ( 57 ). 11. The arrangement according to claim 9 or 10, characterized in that the analog / digital converter are periodically controlled to output a digital temperature value signal, and that the summation stages ( 53 ) after an adjustable predetermined number of received temperature value data a digital signals corresponding to the sum of the temperature values or the arithmetic mean value of the same as inputs to the respective memories ( 54 ), and are reset at the end of each summation cycle. 12. The arrangement according to claim 11, characterized in that the pulse durations of the control signals through which the analogue / digital converters for dispensing tempera value signals are controlled and the repeat frequency of these Im controlling the measuring cycles pulse is / are adjustable. 13. Arrangement for performing the method according to egg nem of claims 1 to 8 with the individual Ver connecting cables individually assigned temperature sensors and with an electronic computer for evaluating the temperature measurement values obtained with the sensors, characterized in that a sensor selection -Switching stage ( 86 ) is provided, which for measuring time intervals defined adjustable duration in cyclical sequence each of the temperature sensors ( 32 ) with the analog input ( 88 ) connects egg nes analog / digital converter ( 52 ), which the output signals converts the temperature sensors ( 32 ) to digital format that can be processed by the computer. 14. Arrangement according to claim 13, characterized in that the temperature sensors ( 32 ) and the sensor-off selection switching stage ( 86 ) are permanently installed. 15. Arrangement according to one of claims 9 to 14, characterized in that the temperature sensors ( 32 ) are arranged in thermal contact blocks ( 72 ) which can be fixed to the consumer connecting pipes ( 21 to 24 ) provided for the temperature measurements and to the bulges of the pipes have complementarily concave curved contact surfaces ( 82 ). 16. The arrangement according to claim 15, characterized in that the heat contact blocks ( 72 ) on the consumer connecting pipes ( 21 to 24 ) can be fixed with the aid of clamping or tensioning devices, preferably as screw clamps with self-centering design of the clamp bracket ( 71 ) and Arrangement of the clamping screw ( 77 ) are formed.