SYSTEM FOR THE DETECTION OF LEAKS IN WATER SUPPLY SYSTEMS

Abstract: The subject of this invention is a method for detecting leaks in a water supply system, in which method the water meter (2) is examined and note made of changes occurring in it. In the method according to the invention, changes are observed during one or more desired length measuring time periods (T) and the duration of flow of a quantity of water (t; t, t1, t2), during the measuring time period is measured using the water meter indicator and the results obtained during the measuring time period are compared with a standard value or with each other and confirm a possible leak.

Description: SYSTEM FOR THE DETECTION OF LEAKS IN WATER SUPPLY SYSTEMS The subject of this invention is a method for detecting leaks in a water supply system, in which method the water meter is examined and note made of changes occurring in it. After a period of time, leaks occur in the water supply system of various buildings. The detection of leaks at the earliest possible stage is very important so that the leak can be repaired and to avoid as quickly as possible any damage caused by the leak. Large leaks are detected relatively quickly since the water consumption increases rapidly and water damage appears very quickly. Small leaks are, however, difficult to detect because the water consumption does not essentially increase and any change is not noticed, for example, by visual observation of the water meter. If the location of the leak in the water pipes is inside the structures, a small water leak can continue for long periods of time and cause considerable damage from dampness, resulting in the structures being demolished and renewed. Various equipment has been developed for measuring the level of water consumption and detecting leaks from the quantity of water consumed and which raise the alarm once a predetermined level is exceeded, in other words, for example, a defined quantity in litres is lost through leakage. With this type of equipment it is possible to measure relatively large leaks in a short period of time. It is not possible, however, with this type of equipment to measure small leaks. The purpose of this invention is to introduce a method which will eliminate the problems with present methods for measuring leaks in the water supply system, ln particular, it is the purpose of the invention to introduce a method which can detect both small and large leaks occurring in the water supply system reliably and rapidly. The purpose of the invention is achieved with a method possessing the characteristics presented in the appended claims. In the method according to the invention, changes are detected during one or several measurement time periods of the desired length and the flow of water or the time taken for a determined amount of water to flow is measured during the measurement time period using the readings of the water meter. The results obtained during the measurement time period are then compared with a benchmark value or with each other and any possible leak determined and notified in some manner. When measuring the flow of a quantity of water, it is possible to measure whether the consumption is steady and continuous over a determined period of time. If the water flow, i.e. consumption is continual, for example, over a period of one or several days, it is generally possible to assume that there is a leak in the system. The leak can be detected with the method when the results are compared with a standard value, in other words, when there is no leak. When the times for a quantity of water to flow are compared to each other, it is possible to determine whether the consumption is consistent over a given period of time. It is then possible to deduce from this whether there is a leak in the system. The method is simple, advantageous and reliable. In the advantageous application of the method according to the invention, changes are detected during the desired measuring time periods and at least two measurements are made, using the water meter indicator, of the time taken for the flow of a determined quantity of water during the measurement time period. The results obtained during the measuring time period are compared with each other and if they are the same value then a leak is confirmed and notified in some manner. The value of the defined quantity of water to be measured can vary in different arrangements. With the method very small leaks can be detected, for example, 0.0125 1/h. The number of measurement results can with a known measurement period range from zero to infinite. When the number of measurement readings is two or more and they are the same value during one measurement period the alarm is given. If, during the measurement period one result differs from the other results no alarm is given. When the water consumption is completely consistent during a defined relatively long time period it can be concluded that there is a leak somewhere. This kind of time period can be, depending on the location or the situation, for example, 1 hour or under one hour or possibly 1-6 hours or more. The method is based on the knowledge that, especially in domestic households, the water consumption is not usually such that the water flow occurs with the same rate of flow for very long periods. Household appliances such as dishwashers and washing machines use water according to their programmes in very short periods and frequently. In showers the consumption is regular but showers are rarely used with a continual even flow of water for more than 15 minutes. If there are no appliances in use which use a continual, even flow of water the consumption is not consistent rather it varies during the measurement time period. Especially during the night, consumption is very irregular and any possible leak is usually already detected during the first night of the leak. When the premises contains appliances consuming water at a steady rate it is possible with the method to take account of this kind of constant consumption beforehand. If, for example, a lawn is watered over a long period of time it can be taken into account and the equipment switched off. If there is no consumption at all, then the method and its equipment will not give any reading at all. In the advantageous application of the method according to the invention, the readout indicator movement showing the consumption of water in the meter is detected with a measuring sensor and the time periods for the pulses received from the readout indicator during the measuring period are measured and are then compared with each other. In this method the movement of the readout indicator is measured as a function of time within the measurement period and then by comparing the lengths of the time periods required for the pulses received, i.e. for a known consumption, with each other, the measurement results are obtained. In the following, the invention is defined in more detail with reference to the attached illustrations, in which: Figure 1 shows the equipment suitable for the method in accordance with the invention, in principle form and viewed from above, figure 2 shows an arrangement of the segment disc used in the equipment viewed from above, and figures 3 and 4 show the results obtained from different measurement periods in certain arrangements. Figure 1 shows the water meter 2 situated in the water pipe 1 and the reading device 3 connected to the water meter. The reading device 3 is connected by cable to the actuator 4. This equipment is located in close proximity to each other in the same area. The actuator in this arrangement includes memory and counter units, equipment providing a distant alarm, warning lights such as LED lights or the equivalent means for informing of its operating condition, disconnection and leak alarm, operating switches, alarm buzzer and acknowledgement button. In addition, for example, an 8 segment disc can be connected to the equipment with which the flow occurring during the measuring period can be read direct in litres. and confirm what kind of leak is in question. The equipment can also be set or fed with a maximum flow rate so that, for example, a pipe fracture gives an alarm immediately the flow exceeds a given maximum value. A valve can be placed in the feed pipe which is closed in this event and the water flow ceases. The equipment can be structured differently in different applications. Figure 2 shows an arrangement with a segment disc 6 fixed on the water meter indicator, which is a disc fitted with the desired number of segment divisions. The pulse can either be taken directly from an analogue water meter readout indicator or from a disc fixed to it. The pulses are measured by recognised methods such as, for example, optoelectronic measuring sensor, i.e. glow/photodiode or laser method or ultrasound technology or other known method. As described earlier the measuring equipment comprises a processor, timing and alarm circuits and its operation is as follows: The LED diode continually emits a visible, invisible or laser light to the water meter readout indicator or to the segment disc attached to it. When the readout out indicator is moving at whatever speed, the equipment detects, for example, a change in the colour of the segment, when a light pulse is reflected back to the photodiode, which sends on/off information to the processor controlled by the timer circuit and the time for each pulse is measured. The processor calculates if more than 2 pulses are received per measuring time period. When 3 pulses have been measured two time periods between pulses have been measured. If more than two pulses have been received, and therefore at least two time intervals between pulses, and the time received between pulses are exactly the same length during the measuring time period (the number of pulses can be >2-°°) the equipment gives the alarm which remains in force until the signal is acknowledged. The measuring period commences from the first following on or off pulse and ends with the last on or off pulse of the measuring period. In the examples shown in figures 3 and 4 the measuring period is 60 minutes. In the situation in figure 3 all the intervals between pulses during the measuring period T for the measuring time period are the same, in other words, the time taken by them is consistent. This being so, the equipment gives the alarm in the situation according to figure 3. In the situation in figure 4 there are different pulse intervals t, t, and t 2 during the measuring period T, and so the alarm is not given. Pulses from a digital water meter can be obtained naturally in an electronic form. In addition, the equipment can also include a memory for the storing of water meter numbers and data as well as a remote reading where the water meter can be read directly from, for example, the water supply utility. The invention is not limited to the advantageous arrangements shown but can vary within the framework of the invention concept formed by the claims.

Claims: CLAIMS 1. A method for the detection of leaks in the water supply system, in which method the water meter (2) is checked and changes occurring there are observed, characterised in that changes are observed during one or more desired length measuring time periods (T) and the quantity of water, or duration of flow of a quantity of water (t; t, t„ t^), during the measuring time period are measured using the water meter indicator and the results obtained during the measuring time period are compared with a standard value or with each other and confirm a possible leak. 2. A method for the detection of leaks in a water supply system according to claim lcharacterisedin that changes are detected during a desired length of measuring time period (T) and the time taken (t; t, t,, t 2 ) for a known quantity of water to flow is measured at least twice using the water meter indicator, the results obtained during the measuring time period are compared with each other and, if the results are the same, a leak is confirmed. 3. A method according to claim 1 or2characterisedin that movements ofthe water consumption readout indicator in the water meter are detected with a measuring sensor and the time of the pulses obtained from the movement of the indicator during the measuring time period are measured and compared with each other. 4. A method according to claim 3 c h a r a c t e r i s e d in that the movement ofthe water meter indicator is measured with an optoelectronic measuring sensor. 5. A method according to claim 3 c h a r a c t e r i s e d in that the movement of the water meter readout indicator is measured with laser technology. AMENDED CLAIMS [received by the International Bureau on 16 September 1997 (16.09.97); original claims 1-5 replaced by new claims 1-4 (1 page)] 1. A method for the detection of leaks in the water supply system, in which method the water meter (2) is checked and changes occurring there are observed, characterised in that changes are detected during a desired length of measuring time period (T) and the time taken (t; t, t„ t 2 ) for a known quantity of water to flow is measured at least twice using the water meter indicator, the results obtained during the measuring time period are compared with each other and, if the results are the same, a leak is confirmed. 2. A method according to claim 1 characterised in that movements ofthe water consumption readout indicator in the water meter are detected with a measuring sensor and the time of the pulses obtained from the movement ofthe indicator during the measuring time period are measured and compared with each other. 3. A method according to claim 2 characterised in that the movement ofthe water meter indicator is measured with an optoelectronic measuring sensor. 4. A method according to claim 2 characterised in that the movement of the water meter readout indicator is measured with laser technology.

Inventors: ESKELINEN REIJO, ESKELINEN, REIJO
Applicants: ESKELINEN REIJO, ESKELINEN, REIJO
Application year: 1997
Main classification: G01M3
IPC codes: G01M3