The present invention relates to a device for detecting fluid leaks; one of its main applications is to detect domestic leaks but it can be applied to any type of fluid distribution network.
This invention is capable of detecting fluid leaks and microleaks using a single device located at the inlet of the distribution network, detecting the leaks based on real time recorded values of flow and pressure.
Different devices are known for detecting liquid leaks, particularly devices that warn of leaks in homes, shops, offices and even industrial facilities. They respond to a leak in two ways: by emitting an optical/acoustic alarm, or by shutting off the general water supply.
These devices act according to three known techniques:
This last leak detection technology can be considered as the most advanced, economical and easy to apply system for houses. However, it has two technical problems.
Firstly, it cannot detect leaks below 3 /h because the flowmeters currently available are not able to detect lower flows.
Secondly, it is slow at determining a water leak. As the detection criterion is the measurement of flow for longer than the reference time, the instruction to shut-off the main water supply is given when large volumes of water have already been released into the home.
Therefore, the proposed technical problem that the new invention solves is twofold: firstly, it detects water microleaks of less than 3 l/h and secondly, it is capable of determining leaks below the maximum flowrate value without waiting for a maximum permissible period of continuous water flow to pass.
The new leak and microleak detector whose patent is sought detects leaks of any type of fluid by measuring flow and pressure in the network.
Basically the new system monitors the fluid flowrate in the network and is provided with an intelligent system that detects abnormal flowrates outside of the ranges of some predefined parameters. These flowrates are those considered as constituting a leak in the network.
Aside from detecting leaks, the new system is capable of detecting microleaks, which are fluid leaks of around 0.15 l/h, typically at joints, taps, valves, pores, or other events involving the loss of very small flows.
The novel detector is inserted into the inlet of the network. For example, in the case of a house, in the mains water inlet, preferably after the utility company's water meter.
Operationally the new detector consists of three elements that are all aligned. The first element is a solenoid valve that is aligned to the direction of flow, which is followed by a flowmeter and finally a pressure switch. These elements are managed and connected to an electronic board, a Programmable Logic Controller (PLC) or similar element, with which the user can interact via a keyboard, keypad, touch screen or any other suitable means to input data and select options.
All these elements can be incorporated into a body or housing that unites them into a single device.
One of the new features of this invention is that the electronic board houses a computer application with two complementary routines that act alternatively. One routine governs the pressure switch and the solenoid valve, and optionally also governs the flowmeter in more developed versions. The second routine governs the flowmeter and the solenoid valve.
The first routine aims to detect microleaks corresponding to fluid losses greater than 0.1 l/h, while the second routine detects leaks greater than 3 l /h.
The alternative operation of both routines ensures that any leak in the network above 0.15 l/h is detected, setting off a warning or alarm in the case of microleaks, and also shutting off the water supply for leaks greater than 3 l/h.
The location of microleaks is done with the first program routine as a one-off test at the user's request, or as part of a scheduled activity that runs at regular intervals.
Its operation follows the assumption that if there are no microleaks and the network is kept pressurised, then the fluid pressure should be kept constant. However, if there is a microleak then the fluid volume will decrease and therefore the pressure will also decrease.
This pressure differential can also be driven by changes in temperature or due to dilation of the network pipes or the fluid itself, so an algorithm is required to discern when there is a microleak and when not.
It is based on a network condition with no fluid consumption, so in the example of a home, all the taps are closed and any devices capable of consuming water are turned off.
In such conditions, the resident program on the electronic board sends a signal to the solenoid valve to put it in a closed position, thereby pressurising the network. In the most basic versions the user must ensure that all the taps are closed. However in more developed versions the application will check that the recorded flowrate is 0 before closing the solenoid valve, so it is assumed that there is no consumption in the network. If this is not the case then the test is suspended.
After pressurising the network, the pressure switch begins recording pressure measurements in the network (Pn) which are analysed in the electronic board. This analysis consists of comparing the recorded value (Pn) with the previous value (Pn-1), verifying if:
(Pn)=(Pn−1)
or
(Pn)≠(Pn−1)
The number of matching results of each type is in turn recorded and analysed by an algorithm programmed into the application, where the existence of a microleak is determined as a function of the time (Tt) and the number of matching results in set periods of time (Tp).
During most of the day, the control of possible leaks is done using the second routine that only detects leaks above 3 l/h.
In this operating mode the electronic board analyses the recorded values from the flowmeter and compares them with reference values that have been introduced or selected with the device's keyboard or keypad, and it controls the time that passes since the start of the assessment.
Leak detection adheres to three principles:
Operationally, this routine has two phases. The reference values (Qmax), (Tmax) are set in the first phase by introducing them directly using the keypad, or by entering additional data such as the number of taps in the house, appliances susceptible to water consumption, watering points, etc. The values of (Qmax and Tmax), as well as the value of (TQmax), are deduced from this data based on the ratio Qn/Tn.
Following this, the actual leak detection is carried out in the second phase. In this phase, the application records the total time that passes since the start of the evaluation (Tt), as well as the flowrate values (Qn), and it carries out an analysis of the information received. (Tt) becomes 0 when the registered flow (Qn) is zero.
The variables used in this analysis are:
According to the described variables, the algorithm programmed in the application's second routine returns the following possible results:
1. If Qn>=Qmax: this case triggers a leak alarm.
2. If Tt>=Tmax: this also triggers a leak alarm.
3. If Qmax>Qn>Qn-1: (see
4. If Qmax>Qn=Qn−1:
5. If Qmax>Qn−1>Qn:
6. If Qn=0: In this case, it is confirmed that there are no leaks, the process ends and recording time resets Tt=0 waiting for the next network consumption.
The leak alarm subroutine involves two basic actions. The first is to send a signal to the solenoid valve to move it to its closed position and shut-off the mains water supply and therefore stop the leak. The second is to send a signal alerting the user which may be a warning light and/or sound for example. Apart from the two basic actions, the alarm subroutine may include other complementary commands, such as sending out a call for assistance to a failure centre, an SMS, email, etc.
The new detector has several advantages: it is able to diagnose a leak in less time than other systems because its algorithm is able to establish whether there is a leak before reaching Tmax and issue an alarm.
It is a scalable and reprogrammable system so that the device can be used in all types of houses by simply inputting the required baseline data about the number of taps, bathrooms, washing machines, etc.
It is able to carry out a test of the water distribution network to detect microleaks on demand or as part of a scheduled task. Therefore, the house's residents will be told when there is a breakage in the network where water is being lost in large volumes. This could be a defect or misalignment that loses fluid in very small amounts and is completely undetectable by the current detection devices.
A sheet of drawings is attached with the aim of illustrating what has been explained in this report, in which:
This example corresponds to a leak detector device based on this invention prepared to be used as a domestic water leak detector.
According to the invention, the new water detector described has a body (1) that is inserted into the household water inlet (2) after the utility company's water meter (3).
The body (1) incorporates a solenoid valve (4), a flowmeter (5) and a pressure switch (6), all operatively interconnected with the control panel (10) which consists of an electronic board (7) in its interior, and a sound generator (14), a keypad (8), an alphanumeric display (9) and a set of pilot lights (11) on its exterior.
The electronic board (7) houses a computer application with two independent routines, which act alternately: one dedicated to detecting microleaks (13) which determines fluid losses greater than 0.15 l/h, and another dedicated to detecting leaks (12) which detects irregular fluid losses greater than 3 l/h.
According to the connectivity diagram shown in
The application housed in the electronic board (7) records the flow values (Qn) measured by the flow meter and the pressure values (Pn) measured by the pressure switch. According to programmed algorithms, it sends operating signals to the solenoid valve (4), to the pilot lights (11), the sound generator (14) and the alphanumeric display (9). The algorithms can be edited via the keypad (8).
Specifically, the variables of Qmax, Tmax and TQmax used in the leak routine (12) are input with via the keypad (8) and correspond to:
These variables give rise to a composite function which is represented in the graph in
According to
The application is started and the values for Qmax, Tmax and TQmax are loaded. (This is phase 1 of the routine and should not be repeated again unless the characteristics of the network are changed)
The flow record (Qn) and time record (Tt) are opened. (This is phase 2 of the routine and it is systematically repeated indefinitely until zero flow or a leak are detected)
A first decision process is carried out with the records of (Qn) and (Tt) with six possible outcomes:
The result [Qn=0] means that there is no network consumption, and therefore no possibility of having a leak. This result ends the application's routine (12), which is then restarted from the beginning.
The results [Qn>=Qmax] and [Tt>=Tmax] initiate a leak subroutine.
The remaining results open a second decision-making process in each case where a second level of results is established:
3 If [Qmax>Qn>Qn−1] it could be that:
4 If [Qmax>Qn=Qn−1] it could be that:
5 If [Qmax>Qn−1>Qn] it could be that:
The results 3.3 [Tt>Tn], 4.1 [Tt>=Tn−1] and 5.1 [Tt>=Tn] initiate a leak subroutine.
The results 3.4 [Tt<Tn], 4.2 [Tt<Tn] and 5.2 [Tt<Tn] do not imply a leak so the application continues.
Lastly, the results 3.1 [Q>Qn−1] and 3.2 [Q=<Qn−1] correspond to an increase and decrease in the recorded flow. In the first case [Q>Qn−1], the application opens a subroutine in which the ratio Qn/Tn becomes Qn/(Tn+x) where x is the total time recorded for Qn−1. (
The leak subroutine involves a process for closing the solenoid valve, and a process for triggering the visual and audible alarms involving the alphanumeric display (9), a pilot light (11) and the sound generator (14).
According to
When the application starts, a process that closes the solenoid valve (4) begins, thereby pressurising the network.
The network pressure record (Pn) and time record (Tt) are opened.
A first decision process is performed with the records for (Pn) and (Tt) with two possible outcomes:
A recount of the identical results is done for a predetermined time interval (Tp) and is stored in the drive.
A second process of decision-making is carried out with the previously stored data by relating the number of repeated results recorded during (Tp) with the total elapsed time (Tt) and two possible outcomes are established that initiate two processes:
End of microleak routine.
Number | Date | Country | Kind |
---|---|---|---|
P201431691 | Nov 2014 | ES | national |
Filing Document | Filing Date | Country | Kind |
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PCT/ES2015/070799 | 11/9/2015 | WO | 00 |