SE460430B - DEVICE TO PREVENT WATER DAMAGE IN BUILDINGS - Google Patents

Description

IS 20 25 30 35 460 430 shut off the water flow or warn of leakage regardless of the size or location of the leak in the system and this without the residents being at risk of being disturbed by false alarms or shutdowns. In addition, the normal use of tap water should not be restricted or hindered. Additional objects and advantages of the invention will become apparent from the following description. They are achieved by the features set forth in the appended claims.

The invention is based on the insight that the tap water system in normal villas, offices, children's cottages, etc. has a much more complicated pressure and flow variation than could be expected. The previously known leakage guards have thus not taken into account that the water supply system often contains air, which can, for example, mean that a leakage is perceived as several short taps and thus does not lead to an alarm. The impact of air is usually related to water heaters, which always contain a certain amount of air, which affects the hot water system. In addition, it is common for the non-return valve that is normally included in the connection to the cold water system to function unsatisfactorily, so that the amount of air can thus also affect the latter system and thus the entire pipe network. A very serious situation can then arise, e.g. when showering, if hot water -pressed into the closed cold water system.

According to the invention, a pressure sensor senses the pressure after the shut-off valve in a closed line system. The pressure is continuously sensed so that if certain time and pressure conditions are met, the said valve is controlled to assume an open or closed position. Said pressure conditions are gradually adapted to the prevailing pressure conditions within the line system so that commands for e.g. opening of the valve can be given at a very small measured differential pressure. This avoids the above-mentioned risk of burns as a result of hot water in cold water systems and other inconveniences. However, the conditions or wsfvk = rsaauwwaumw fl a ~ - w »'- - ~' - 'i 10 15 20 25 30 35 3 460 430 parameters that are to provide the control can not be designed in one and the same control circuit, since different systems e.g. with or without air has such different characteristics. In order to achieve a generally usable, easily installable construction, the control unit can therefore be provided with at least two main programs, one for each main type of system. According to a further aspect of the invention, the control means must in various ways warn the user if the wrong main program has been switched on and despite such incorrect connections, the main function, ie. shutdown in case of major leakage, be in force.

An embodiment of the invention will now be described in more detail with reference to the accompanying drawing sheets, on which Fig. 1 is a schematic wiring diagram of a device according to the invention.

Fig. 2 is a simplified block diagram of the control program for opening or closing the shut-off valve.

Fig. 3 is a diagram showing how the pressure can vary with time during sensing with the pressure sensing device.

Fig. 4 shows the pressure variations during a normal tapping at a tapping point.

Pig. 5 shows the pressure variations when all tapping points are calculated to be closed.

Fig. 6 shows the pressure variations in the event of a leak or a very long drain.

Fig. 1 schematically shows a device according to the invention connected to a pressurized water line 11 entering a building. The device comprises a shut-off valve 12 connected in the line 11 10 15 20 25 30 460 430 in the form of a normally closed solenoid valve and a pressure sensing device 13 connected thereto to the line and a control means 14 for opening and closing the valve 12. The solenoid valve thus breaks the incoming pressure water line and thereby provides a closed tap water system within the building. The pressure in this is continuously sensed with the pressure sensing device 13 in the form of a suitable pressure sensor. The solenoid valve and the pressure sensor are connected to the control means 14, which comprises a programmable electronic unit for controlling the valve as will be described in more detail in the following. The water supply system usually contains a hot water heater 15 and several tap water points 16, of which only one mixer is shown. The hot water heater is supplied with cold water in the usual way via a connection line 17 and a non-return valve 18. Furthermore, hot water is extracted from the water heater by means of a hot water line 19, which together with a cold water line 20 is connected to the mixer 16.

The device is easy to install even in existing buildings. The solenoid valve and the pressure sensor can thus be connected to the input water line, e.g. directly after the water meter.

Otherwise, no intervention is needed in the water supply system, only access to power for feeding the electronics unit.

This is conveniently placed in an easily accessible place; for example at the front door. The electronics unit has an instrument panel 22 for manual actuation of the control system. With a first switch 23 you can easily turn off the water by setting the switch to the OFF position. This is conveniently done for each longer absence from the house. With the next switch 24 you can switch off the automation for shutting down the system. This can e.g. be practical for expected longer flow such as for a longer period of watering, etc. A push button 25 is also available for resetting the electronics, if it has alarmed at any time. As previously mentioned, the control system is arranged to give an alarm or turn off the solenoid valve, if the sensed pressure- TWÜQWÛÜRIN fl N-azwøufßa- -lwfr-vwr-'mf = 1 ~ M -fl f “arm - ~ - '~~ -'" fm- www ~ f '- - f- -r 10 15 20 25 30 35 460 430 the variations over different time periods do not correspond to programmed predetermined values.To achieve a simple but still usable system, not all imagined normal tapping situations can be programmed but the user can set on the panel 22 how long he wants to be able to drain water without the system starting to alarm for leakage, this time which can be called comfort time is thus adjustable by means of a rotary switch 26. You can for example choose between periods from 5-20 minutes. the panel is also alerted for normal leakage, so-called coarse leakage, but also for very small leaks, so-called drip leakage, in which case alarms are given in the form of flashing signal lamps 27.

In addition to warning of leaks, the device can also be used to warn, if the water supply system has been unused for a long time, and thus alert in a suitable way for feared illnesses for the elderly, etc. As stated in the introduction, water supply systems in normal buildings can be divided into whether they are under the influence of trapped air or not. If the system is under the influence of air, this is characterized by great inertia and must therefore be treated separately by electronics. Since a very large part of the water supply systems are of the latter type and since moreover the type of system cannot always be predicted, the electronics are easily adjustable on these two main types of water supply systems. If deemed appropriate, of course, other setting options and additional main types of programs may be possible. In the program shown, the setting is made by means of the rotary switch 26, which can be set in three so-called A-positions for vented or mute systems without air and three so-called H-positions for systems exposed to hydrophore effect or other resilient action.

The design of the control unit of the electronics unit is shown in the simplified function diagram according to Fig. 3. The program is started by switching on the switch 23 or pressing the reset button 25 on the control panel 22. 10 15 20 25 30 35 .w, rWp§w fl; w rs rlssawaawawnwumømwa »wunmuiluu 460 430 Thereafter, the monitoring is initiated i.a. with zeroing of the program's counting functions and testing of the signal lamps on the control panel 22. The pressure from the pressure sensor 13 is read in and if this falls within a reasonable interval 29 the value is used to calculate a suitable comparative pressure, which in the diagram is called setpoint 30. If the sensed line pressure falls outside the specified pressure range, e.g. SO-800 kPa, the program gives a direct alarm for coarse leakage 31, which means that the solenoid valve 12 closes and the signal lamp 27 lights up.

This serves two purposes, partly to turn off the water immediately in the event of very large line breaks, and partly to guarantee that the device is only used in systems for which it is adapted.

The setpoint of the pressure 30 is calculated not only on the basis of the last measured pressure but as a suitable aggregation of the most recently read pressure values. Thereafter, the electronics assume a scan mode 32, where the pressure is sensed at the same time as a number of query sequences are reviewed. The first 33 asks if the switch 23 is on or not. Even in the off position 34, the electronics retain certain functions in order to e.g. be able to detect very small leaks, so-called drip leakage.

This can e.g. signaling, if the pressure has dropped more than 100 kPa in less than 6 hours. If the electronics unit is switched on, it is checked again if the pressure remains within reasonable values and then if the automation 36 is switched on.

As previously mentioned, it can be temporarily disconnected using the automatic button 24 on the control panel. Furthermore, it is checked 37 if the time for activating the security alarm has not expired. Finally, there is a function 38 for sensing if the pressure is unchanged high or if a certain pressure drop could be sensed. Such a pressure drop can e.g. achieved by opening a tap water tap. If the pressure drop exceeds a certain value, the solenoid valve 12 must be opened so that normal draining can take place. In the event of a small pressure drop, the program returns to the scan mode 32 and goes through the previously mentioned conditions again. 10 15 20 25 30 35 460 430 The pressure difference for opening the solenoid valve 12 should be chosen as small as possible to avoid pressure variations in the system and above all to avoid that hot water can flow "backwards" within the system by e.g. leaking non-return valves 18 and entering the cold water line 20.

However, the differences should not be chosen too small, as the solenoid valve then has to work unnecessarily much, which causes wear and can be disturbing. With such a sensitive device, it also becomes difficult to measure so-called drip leakage. Suitable values have therefore been found to be at least 50 kPa in the A-program essentially without air and at least 30 kPa in the H-program, where the system is exposed to the effect of trapped air. When the valve has entered open position 39, it is up to the program to determine whether it is now a question of a normal filling or whether a leak has occurred. Before this control phase enters, however, the program must first check whether the selected setting of the main program corresponds to reality, ie. if an A setting is incorrectly selected for a system containing air. This is done simply by adding the number of openings to check if these do not exceed a certain selected value 40, before the so-called the comfort period has begun to run. If this is the case, the appliance must sound for coarse leakage 31. The periodic constant should be selected somewhere in the range of 20-40 openings, as such a large number of very short drains is unlikely in a normal draining system. When the comfort time 37 has started to run in the control phase, the program goes through a number of new conditions and checks as before if the alarm is switched on, if the pressure stays within reasonable limits 41 and if the automatic is switched on or off. Then the program must detect if drip leakage 42 is present when the automatic is switched on. The drip leakage is arranged by measuring the time between each reset, ie. each intake of the scan position 32 and the next opening of the solenoid valve 12, and if two or more such times agree give alarm for drip leakage. The upper limit for recording such periods can, for example, be set to one hour. If no drip leakage is present, check 43 whether the drain is still within the set comfort time and if so, the pressure in the system is read and a new setpoint for the pressure is calculated 44. Then the solenoid valve closes for a short moment to detect 45 whether the pressure is reduced or not in the temporarily closed system. If no pressure drop can be detected, it is assumed that the tapping is completed and the program can return to scan mode 32 after resetting the comfort time 46. Otherwise it is assumed that the tapping continues, causing the valve 12 to reopen, time is deducted from the comfort time and the periodic the constant is reset 47.

Thereafter, the control phase is run again. The pressure drop during said control periods 45 shall not exceed 30 kPa in both main programs to effect re-opening of the valve. However, the time period for pressure sensing should be longer in the H-program in relation to the A-program, preferably 720 seconds in relation to 1-10 seconds. Thus, a lower pressure drop is required to effect opening of the valve in the control phase than in the position of the first opening 35. This ensures that the pressure difference never becomes so large that hot water can be feared flowing backwards and out into the cold water lines. first opening to avoid the above-mentioned inconveniences with too small pressure differences. In addition, the risk of burns is much less during the first tapping, as the water in the hot water line has time to cool down if the mixer 16 is switched off for a certain shorter period.

If the tapping within the said control phase continues so long that the comfort time expires, a so-called warning phase 48 to give the user a warning that the system will shut down if tapping continues. This is done in said phase 48 by closing and opening the valve in cycles of 10-20 seconds and after the last closing measuring the pressure for 10 15 20 25 30 460 430 to check if this is still below the setpoint by a difference greater than that which controlled the program during the control period 45. If the pressure does not become higher, alarm for coarse leakage 31 is alerted, but otherwise the system returns to the scan mode 32. By means of the warning phase 48, e.g. a showering person will get the comfort time to restart by turning off the shower for a short period of time.

With the help of the described program, it can always be ensured that the device switches off for more serious leakage, regardless of whether the user has set the detection to the wrong main program.

If an H-system is present but the device is set to an A-system, the gross leakage warning would be out of play, unless the periodic constant is introduced. Since the pressure drop here is too slow to be registered within the control period 45, the leak would be perceived as a number of shorter individual taps and thus not give rise to a warning or shutdown. For the user, each error setting will result in a number of unjustified interruptions, which will lead him to change the setting. Due to the periodic constant, the solenoid valve can also be switched off if the pressure drop continues without the system being used normally. The pressure drop that is then sensed will correspond to the described mode, if the wrong program is switched on.

In the following, the function of the device will be further described in connection with pressure curves for different bottling or leakage situations.

Fig. 3 illustrates what the pressure reduction processes during the control periods 45 can look like. Thus, when the valve is closed at t1, the pressure can either drop rapidly at a larger drain, curve A, or slowly, if some form of drip leakage is present, curve B. The dashed curve C illustrates how a suitable limit value can be selected to most drains should be perceived as normal and load the comfort time without the previously mentioned risk of sudden hot water shocks in the cold water line. The pressure drop AP should thus be selected less than 30 kPa and this should be achieved during the time 1-10 seconds, if the system lacks trapped air volume, while if the system is more sluggish due to trapped air, said time should be increased to 7-20 seconds. I Eig. 4 shows the course of events during a normal bottling, for example if someone washes their hands or if a dishwasher is refilled. Initially, the solenoid valve 12 is closed and the pressure sensor 13 senses the pressure in the closed line system. When a mixer 16 or the like. opens at t1, the pressure drops gradually until the selected first pressure difference is reached at t2. Said pressure difference should, as mentioned, be at least S0 kPa in the first main program and at least 30 kPa in the second, which contains air. When the valve is opened, the pressure rises to the supply pressure, almost as if there were flow losses in the valve. The control program is now in the so-called the control phase, whereby a new calculated setpoint of the line pressure is produced at t3 after approx. 20 seconds. Then the valve closes at td and a control period 45 begins. In the example shown, the pressure drops more than the set limit value, which is interpreted as a continuous tapping, whereby the valve is reopened at t5. A new pressure calculation takes place at t6 and a new control period is completed between t7 and t8. When tapping ceases at t9, the pressure is raised slightly again due to reduced flow losses, whereby the next calculated setpoint of the pressure, which is calculated at t10, becomes slightly higher. During the next control period between t11 and t12, the pressure does not drop, so the comfort time is reset and the sensing returns to the scan mode 32.

When the management system is at rest, ie. the electronics are switched on but all tapping points are closed, the position according to Fig. 5 enters.

Since it is unusual for a pipe system to be completely clogged due to dripping taps etc., the valve 12 will be opened with a. .-.; -. «N fi.fifi w_.r, i» s 10 15 20 25 30 35 460 430 11 with some long intervals. It is convenient to choose not to warn of leaks, which are so insignificant that they can not cause damage. The example shows the pressure curve for the pipe network during such a drip sequence. At t1, the pressure is calculated as before, after which the valve closes for a control period at t2. At the end of the period t3, however, no sufficient pressure difference has been measured, which means resetting the comfort time and continuing to close the valve.

At t4, however, the pressure has dropped so far that logic 38 commands the opening of the valve. The system is thus pressurized again and new control periods begin at t5 and t8. A new opening of the valve also takes place at t7. The time between t3 and t4 resp. t6 and t7 etc. is measured and stored in the drip leakage logic 42 and when two or more similar times have been received in succession, an alarm is given for drip leakage. It is suitably chosen that three times should be the same and that each time should not be longer than one hour. Such a choice ensures that no random warning for drip leakage can hardly occur and that a warning for insignificant leakage is avoided.

The most important function of the device is of course to turn off the flow and give an alarm if a major leak occurs. Such a stage is illustrated in Fig. 6 and in the same way as in Fig. 5 a tapping is initiated with the pressure decreasing until the valve 12 opens and then a certain number of control periods K1 to Kn are undergone until its comfort time e.g. 10 minutes elapsed at time t1. Now the so-called the warning phase 48, where the valve 12 is first closed for a certain time, e.g. 10-20 seconds. In this case, the closed line system is emptied and the pressure decreases until time t2, when the valve opens again and the system is pressurized. This is repeated for another period or periods until the valve closes again at t3. If the water tap is still open or if a leak has occurred, the pressure drops to 0 at t4. A last control measurement takes place at t5 after e.g. 10 seconds from t3 and if the pressure then 460 450 12 * §_ f:. .W 1, is still more than a given difference from the calculated setpoint, is alarmed for coarse leakage and the solenoid valve 12 is closed and can only be opened by means of manual reset.

The invention is of course not limited to the exemplary embodiment shown, but can be varied in many ways within the scope of the appended claims.

Claims (8)

_; 460 450 13 Patent claims Device for preventing water damage in buildings due to leakage between one or more drain points (16) and an automatically controlled shut-off valve (12) in an incoming pressurized water line (11) comprising a control means (14) and a pressure sensing device (13) arranged in the pressurized water line after the shut-off valve, the control means during normal tapping at different tapping points in the building being arranged to open the valve from a normally closed position but in case of leakage warn of this and / or lock the valve in closed position, characterized in that the control means has a programmable electronic unit, which is arranged to register different pressures, pressure differences and times as well as the number of certain events to produce said warning signal or locking of the valve (12) in closed position, if the registered parameters do not fall within programmed values for imaginary normal drains in the water supply system in question. ; that the electronics unit is arranged to open the valve, when a certain pressure difference (38) is measured relative to a calculated comparative pressure (30, 44) and to successively calculate new values of the comparative pressure (30, 44) adapted to prevailing external pressure conditions in the incoming pressurized water line (11) : and that the electronics unit is adjustable to at least two different main programs, a first with parameters adapted for water supply systems containing a certain amount of trapped air and a second for systems substantially without any such air volume, said pressure differential being assigned a higher value and / or time periods for pressure sensing lower values in the second main program. Device according to claim 1, characterized in that the electronics unit is set to close the valve for one or more short control periods (45) during a certain normal tapping and that said given pressure difference for opening the 460 430 14 'valve (12) is arranged to assume a second lower value during these control periods. Device according to claim 2, characterized in that the electronics unit is arranged to register the line pressure before each control period (45) and thereafter use two or more such registrations to produce said calculated comparative pressure (44). Device according to claim 2 or 3, characterized in that the electronics unit is arranged to register the number of openings of the valve (12) and to reset this registration and close the valve, if the second lower pressure difference is not reached, but that otherwise and after a certain number of such openings lock the valve in the closed position and / or sound an alarm signal. Device according to claim 4, characterized in that the electronics unit is arranged to register the time phase (47) for the control periods (45) so that if the number of openings of the valve (12) exceeds a certain number, preferably 20-40, without any time phase being registered lock the valve in the closed position and / or give a warning signal. Device according to one of the preceding claims, characterized in that the electronics unit is arranged (29, 35, 41) to lock the valve (12) in the closed position and / or emit an alarm signal, if pressure is detected which is outside the range 50-800 kPa. Device according to one of Claims 2 to 6, characterized in that the first measured pressure difference (38) for opening the valve (12) is at least 30 kPa in the first main program and at least 50 kPa in the second main program, that the following other pressure differences measured during the control periods (45) shall not exceed 30 kPa in both Ü Lv »- -w-: w-w fl-fl ~~ -» ~ vm- <~ af = ~ fl vl ~ vrf 'v ~' ~ "'f" ~ "' 460 430 15 programs and that said control periods should be 7-20 seconds in the first main program and 1-10 seconds in the second main program. Device according to one of Claims 4 to 7, characterized in that the electronics unit is arranged to measure times between each reset (46) and the next opening (39) of the valve so that if two or more in succession within a certain longer period of time substantially correspond provide a warning signal and / or lock the valve in the closed position.