Regulating pump device in water supply mains, method

Abstract

A pump system for a water supply mains has at least one pump device, a pressure detecting sensor at the pressure side of the pump device, a flow detecting sensor of the pump device, several pressure sensor units (D) remote arranged remotely from the pump device in different part regions of the mains, and a pump control device. The control device includes a model formation module designed in each case to produce a model (A) representing pressure loss from the pressure sensor to the position of the respective pressure sensor unit (D), based on several pressure measured values of at least two pressure sensor units (D) for the at least two associated part regions. The control device is designed for regulation of the pump device based on produced models (A), as well as to a corresponding method for regulation of a pump device in a water supply mains.

Claims

1. A method for regulating at least one pump device in a water supply mains, the method comprising: dividing the water supply mains into a plurality of part regions and detecting, in at least two of the part regions, a respective pressure (p.sub.cri) at a respective critical location at several points in time; simultaneously detecting a pressure (p.sub.dis) at an exit side of the at least one pump device; determining respective pressure losses for the at least two part regions based on the thus detected pressures; creating in each case a model (A) representing an expected pressure loss (p.sub.pipe) as a function of flow (q) and time (t) of the at least one pump device, based on the determined pressure losses for the at least two part regions; and regulating the at least one pump device based on the created models (A).

2. The method according to claim 1, wherein simultaneously with the detection of the respective pressure (p.sub.cri) at the respective critical location, the flow (q) of the at least one pump device is determined and the models (A) are created such that they represent the expected pressure loss (p.sub.pipe) in the respective part region.

3. The method according to claim 2, wherein the flow (q) of the at least one pump device is detected for regulation of the at least one pump device, and the pressure losses (p.sub.pipe) to be expected in all part regions are determined for this point in time and detected flow by the models (A), and an exit pressure of the at least one pump device is regulated to a desired pressure (p.sub.ref) which compensates for these expected pressure losses.

4. The method according to claim 1, wherein measured values of the respective pressure at the respective critical location at several points in time are stored, and an evaluation for creating and updating the respective models (A) is effected after a certain number of measurements or after a certain time span.

5. The method according to claim 1, wherein a leakage in the water supply mains is detected by regular, optionally daily, detection of the flow (q) of the at least one pump device at a certain point in time or in a certain time span, and by a comparison of measured values of the thus detected flow (q) among one another or with at least one predefined limit value.

6. The method according to claim 1, wherein a probable location of a leakage in the water supply mains is determined by a comparison of a pressure loss currently measured for a part region with an expected pressure loss for this part region according to the respective model (A).

7. The method according to claim 1, wherein a probable location of a leakage in the water supply mains is effected by comparison of an average pressure loss for a part region measured in a defined time interval with an average pressure loss to be expected for this part region in a same time interval according to the respective model (A).

8. The method according to claim 1, wherein a probable location of a leakage in the water supply mains is determined by comparison of an expected pressure loss for at least one operating condition according to a first model (A.sub.Init) for a part region with the expected pressure loss for a same operating condition of a same part region according to a second updated model (A).

9. The method according to claim 5, wherein the leakage in the water supply mains is detected daily.

10. The method according to claim 6, wherein the leakage is determined in the part region when in the current pressure loss is equal to or larger than the expected pressure loss.

11. The method according to claim 7, wherein the leakage is determined in the part region when the measured average pressure loss is equal to or larger than the expected average pressure loss.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

(2) FIG. 1 is a schematic diagram of a water supply mains having a pump system according to an embodiment of the invention;

(3) FIG. 2 is a schematic diagram showing the function of a pump system according to an embodiment of the invention;

(4) FIG. 3 is a p-q diagram in which the desired pressure is plotted for different flows;

(5) FIG. 4 is two diagrams depicting nocturnal flow measurements for detecting mains leakage;

(6) FIG. 5 is a schematic diagram showing the localization of a leakage according to a first embodiment of the invention; and

(7) FIG. 6 is a schematic diagram showing the localization of a leakage according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1 schematically shows a water supply mains having a pump system according to an embodiment of the invention. The water supply mains comprises a feed conduit 2, in which a pump unit 4, for example one or more pump assemblies, is arranged. The water supply mains branches into several branches 6 downstream of the pump unit 4. Pressure sensor units D(D.sub.1 . . . D.sub.n) are arranged in the shown individual branches 6 at critical points. In the example shown here, the pressure sensor units D are equipped with radio communication modules, which permit a data transmission, via a mobile network according to the SMS standard, to a control device 8. The pressure sensor units D moreover comprise measured value memories, in which pressure measured values with a time stamp and stored at different points in time are stored, so that the individual pressure measured values can be assigned to exact points in time at which they were acquired. The pressure sensor units D are designed such that they transmit the stored pressure measured values by radio to the control device 8 once daily. The pressure sensor units D measure the pressure value at the critical points, for example every half hour, distributed over the day. More or fewer pressure measurements can also be effected. The number of pressure measurements should be selected such that, where possible, all critical operating conditions can be sufficiently accurately acquired over the day.

(9) The control device 8 serves for the control or regulation of the pump unit 4. In particular, the control device 8 regulates, which is to say controls with a closed loop, one or more pump assemblies of the pump unit 4 with regard to the speed, such that a desired exit pressure at the pressure side of the pump unit 4 is achieved. This is detected by a pressure sensor 10. Moreover, a flow sensor 12 is arranged in front of the branching, so that it centrally detects the flow through the pump unit 4 and thus through the complete water supply mains situated downstream. The pressure sensor 10 and the flow meter 12 deliver their measured values or readings to the control device 8, wherein these preferably permit a continuous measurement. The pressure sensor 10 and the flow sensor 12 are preferably arranged in the vicinity of the control device 8 so that a lead connection can be provided here for the data transmission.

(10) The regulation or control of the pump unit 4, according to the invention, is described in more detail by way of FIG. 2. In the example shown in FIG. 2, several pump assemblies 14 are shown as a pump unit, and these can be operated parallel or in an alternating manner, depending on which delivery power is desired. The pump unit 4 thus forms a pump station, which has one or more pump assemblies 14 for the pressure increase of the water. The control is effected on the basis of several models A(A.sub.1, . . . A.sub.n) which represent the pressure loss in individual part regions of the water supply mains 1. According to the invention, in each case an associated model A for the pressure loss between the pressure sensor 10 and the respective pressure sensor unit D is created for several pressure sensor units D, in this example for all pressure sensor units D. Thus, different models A for the individual critical points in different branches 6 of the water supply mains 1 are produced, and these represent the pressure loss in these part regions of the water supply mains, depending on the time t and the flow q in the entire water supply mains 1, the flow being detected by the flow sensor 12.

(11) The models A are formed on the basis of the pressure values p.sub.peri(p.sub.eri, 1 . . . p.sub.eri,n) detected by the pressure sensor units D at different points in time. The pressure sensor units D detect the pressure value at several points in time, for example every half hour as described above. These detected values are led to the control device 8 in a regular manner, for example once per day. There, pressure measured values of the pressure sensor 10, the flow measured values of the flow sensor 12, as well as the associated time are acquired as further data. The models A(A.sub.1 . . . A.sub.n) are formed in the model formation module 16 on the basis of these data. The models A are stored in parameter memories 18 in the control device 8 for all part regions. Every time when newly acquired measured values are sent to the control device 8 from the pressure sensor units D, these are again processed in the model formation module 16 with the detected pressure measured values form the pressure sensor 10 and the flow measured values from the flow sensor 12, and the produced models A are updated. With the processing in the module formation module 16, thereby a temporal assignment of all measured values at individual points in time is carried out, i.e., a pressure measured value p.sub.eri, a pressure measured value p.sub.dis of the pressure sensor 10, as well as a flow measured value q of the flow sensor 12 is assigned to each considered point in time. This assignment forms the model A and is stored in the memory 18 in an updated manner. Each of the models A thus indicates a pressure loss which is to be expected at a certain point in time at a certain flow q in the complete network, in the individual part region. Thereby, the structure of each of these models is given, for example, by:
p.sub.disp.sub.eri=a.sub.0+q.sup.2(a.sub.1+a.sub.2 cos(t)+a.sub.3 sin(t)+a.sub.4 cos(2t)+a.sub.5 sin(2t)+a.sub.6 cos(3t)+a.sub.7 sin(3t)
p.sub.dis thereby corresponds to the pressure at the pressure sensor 10, p.sub.eri corresponds to the pressure at the pressure sensor unit D, q is the flow at the flow sensor 12. The parameters a(a.sub.0, . . . a.sub.7) are produced in the model formation module 16 on the basis of the acquired measured values. The fixed parameter o indicates the frequency of the daily variations in the model.

(12) Preferably, data of only one day are taken into account for model formation, so that the measured readings over only one day need to be stored by the pressure sensor units D, as well as in a data memory 20 of the control device 8. The data volume to be processed is thus kept small.

(13) The regulation of the pump unit 4 is effected on the basis of the currently measured flow q and the time t in a manner such that the pressure loses p.sub.pipe(p.sub.pipe, 1 . . . p.sub.pipe,n) to be expected for this flow and at this point in time can be read out from the thus formed models A. The desired pressure which is necessary at the exit side of the pump assembly 14 is determined in a desired pressure evaluation model 21 which comprises a adders S(S.sub.1 . . . S.sub.n), desired pressure memories 23 as well as a comparator 22. The pressure losses P.sub.pipe to be expected are in each case added to an associated minimal pressure or reference pressure P.sub.eriref, which is read out from the respective desired pressure memory 23 and which is to be achieved in each case at the critical points, at which the pressure sensor units D are arranged. This is effected in the addition steps S(S.sub.1, . . . S.sub.n) in the control device 8. There, the respective reference pressures p.sub.eriref(p.sub.eriref, 1 . . . p.sub.eriref,n) are added to the determined pressure losses p.sub.pipe to be expected. The reference pressures p.sub.ref(p.sub.ref, 1 . . . p.sub.ref,n) to be achieved for the individual part regions are determined from these additions. These are then compared to one another in a comparator 22, and the greatest determined reference pressure p.sub.ref is led to the speed controller or speed regulation module 24 in the control device 8. A regulation or closed-loop control to the desired pressure p.sub.ref takes place in this control device, while taking into account the pressure p.sub.dis currently detected by the pressure senor 10. The speed controller 24 issues the rotational speed n for the pump assembly or assemblies 14. Additionally, the control device 8 in this example comprises a selection module 26 which ascertains whether one or more pump assemblies 14 are used and with which speed n they are driven and, if not all pump assemblies 14 are used, which of the pump assemblies 14 are applied. Thus, a uniform utilization of the several pump assemblies 14 can be achieved by the selection module 26.

(14) The use of the models for the individual part regions of the water supply mains 1 which correspond in each case to one or more branches 6, in which in each case a pressure sensor unit D is arranged, has the advantage that the actual exit pressure of the pump unit 6 can be adapted very precisely to the actual requirements, and thus an adequate pressure in the individual part regions is always ensured and simultaneously the energy application can be minimized. Moreover, the individual part models A can be adapted flexibly to the changes of the requirement in the water supply mains 1 via the data acquired by the pressure sensor units D.

(15) With the embodiment example according to FIG. 2, it is to be understood that infinitely many part regions with pressure sensor units D and accordingly infinitely many models A can be present. The signal processing and the evaluation of the reference pressure P.sub.ref for the individual part regions is effected in each case independently, so that a corresponding number of adders S and desired pressure memories 23 as well as memories 18 is provided, which is indicated in each case by the three points between the signal lines in FIG. 2.

(16) FIG. 3 shows a pq-diagram, in which the pressures is plotted over the flow. One can recognize that it is always the highest summed pressure value p.sub.ref for the respective flow which is selected as a reference pressure p.sub.ref, to which the pump unit 4 is regulated. The reference pressure p.sub.ref, to which the pump unit 4 regulates is characterized by the unbroken line.

(17) The control device 8 of the pump system according to the invention moreover permits possible leakages in the water supply mains 1 to be detected and localized. For this, an average flow value at the flow sensor 12 is detected by the control device 8 daily in a defined time interval Dt beginning at a certain point in time which is always recurring (see FIG. 4). This is preferably effected at night, for example midnight, when the flow is the least and is largely constant over several days. This flow Dt is stored over several days and compared, as is plotted in the diagram below in FIG. 4 for the days 1d to 9d. One can conclude a leakage at a location of the water supply mains 1 from the rise of the flow which is recognizable here, beginning on day 4d up to day 9d. When the control device 8 recognizes such an increase over several days or alternatively or additionally the exceeding of a predefined limit value, then a leakage is concluded from this, and this is signaled in a suitable fashion as the case may be.

(18) It is then possible in a next step to localize in which of the part regions, which are assigned to the pressure measurement units D, the leakage is probably situated, by way of the formed models A. For this, a first method is described by way of FIG. 5. A suitable program module, specifically a leakage detection module 29 (FIG. 1) can be present in the control device 8, for carrying out this method. For leakage recognition, the exit pressure P.sub.dis of the pump unit 4 is considered at a certain point in time t, as well as the pressure P.sub.cri(P.sub.cril . . . P.sub.cri,n)detected by the respective pressure sensor units d at this point in time. The difference P.sub.dis- P.sub.cri, n, i.e., the actual pressure loss at a certain point in time t, is formed from these. These values R(R.sub.1 . . . R.sub.n) in a residual value formation step in each case separately for each part region, i.e., separately for each model A(A.sub.1 . . . A.sub.n), are subtracted from the expected pressure losses according to the models A at the respective points in time and flows, i.e., the pressure losses P.sub.pipe (P.sub.pipe, 1 . . . P.sub.pipe,n). In this manner, the residual values r(r.sub.1 . . . r.sub.n)are formed for the individual part regions. Then, in a localization module 28 or localization step 28, in a next step, one considers as to which of the residual values r is larger, which is the same and which is smaller than 0. The probability of a leak is then localized in that part region, in which the residual value r is equal or smaller than 0. That is, it is assumed that a leak occurs where the pressure loss is greater than expected. In the other part regions of the water supply mains, the pressure due to the simultaneously reducing flow would in return increase, so that there the residual value r is greater than 0. This means that the probability of a leakage is greatest where the residual value is 0 or smaller than 0. The influence of fluctuations due to the water consumption when considering this is eliminated, due to the fact that it is only the polarity of the residual values and not the actual value which is considered.

(19) A second method for localizing leakages is described by way of FIG. 6. This method differs from the previous method described by way of FIG. 5, due to the fact that no residual value between the expected pressure loss and the actual pressure loss is formed in the residual value formation steps R(R.sub.1 . . . R.sub.n), but the parameters of the current models A are compared with parameters of the valid models A.sub.Init(A.sub.Init,1 . . . A.sub.Init,n). That is, after the updating of a model A on account of new measured values from the pressure sensor units D, the thus produced model A is compared with the respective model A.sub.Init for the same part region which was previously applicable or valid. That is, the parameters of the one model in the residual value formation steps R are subtracted from the associated parameters of the other model. Thereby, the parameters, i.e., the pressure loss values for the same operating condition, i.e., the same points in time and flows are taken into account. The thus formed residual values r(r.sub.1 . . . r.sub.n) are compared with one another in the localization module 28. Thereby, it is analyzed in the localization module 28 as for which of the part regions the parameters of the model A have changed. Thereby, not only the parameters in the part region, in which the leakage is situated will change, but the parameters a according to the above formula and representing the pressure loss will positively change in the part region in which the leakage is situated, whereas they change negatively in the part regions in which no leak occurs. That is, the parameters of the model A which represent the pressure loss increase for the part region in which a leakage is present, while they reduce for the other part regions. This is analyzed in the localization module 28, so that then the part region in which the leakage has occurred can be determined according to the model A(A.sub.1 . . . A.sub.n).

(20) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.