EP1730484A1

EP1730484A1 - Method for actively monitoring pipelines

Info

Publication number: EP1730484A1
Application number: EP05716452A
Authority: EP
Inventors: Stefan Windisch; Alexander Dr. Med. Heinl
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-02
Filing date: 2005-03-30
Publication date: 2006-12-13
Also published as: US20080266125A1; WO2005095916A1; DE102004016378A1

Abstract

The invention relates to a method for actively monitoring pipelines guiding pressurized media and consumers, which are connected to the respective pipeline or pipeline system, by means of differential pressure measurement. According to the invention, monitoring occurs as to whether permanent and quasi-constant consumption takes place during a specific time period, preferably at the transfer point or behind the point of transfer between the supply device and consumer connection in a continuous manner or in predetermined cycles. If this is the case, it is possible to deduce an abnormal state, e.g. a leak, and an alarm is triggered or the downstream pipeline system is blocked. A series connection, consisting of a first pressure sensor, an electrically or hydraulically actuatable valve and a second sensor, is provided on the device side at or behind the transfer point between the supply device and consumer connection, wherein a control electronics system is connected to the pressure sensors and the valve actuation device, in order to produce an error signal when a decrease in pressure has been recognized per time unit after the valve has been blocked in a controlled manner.

Description

Processes for active monitoring of pipelines Description

The invention relates to a method for active monitoring of pipelines which carry pressurized fluid media, as well as consumers connected to the respective pipeline or the pipeline system by means of differential pressure measurement, according to the preamble of patent claim 1.

For piping systems, e.g. a domestic water supply, arrangements are known which contain sensors which are able to detect leaking water. Such sensors have an alarm device that signals, for example, optically and / or acoustically leaked water. In all cases of the use of such sensors, however, damage has already occurred and a more or less large amount of water is in a building or an apartment with all known consequential damage.

In addition, mechanical shut-off devices are known which are integrated, for example, in the water supply hose of washing machines, dishwashers or the like consumers. In the event of sudden changes in pressure, e.g. If the water supply hose bursts or slides out of a hose nozzle, the integrated valve closes. Although the amount of water escaping can be minimized here, such solutions of the prior art are not suitable for monitoring complex pipelines or piping systems with several connected consumers. In addition, a minimum pressure differential is required to operate the valve.

DE 196 35 789 AI shows an electronic consumption measuring device for liquids or gases, two pressure sensors being provided there in the line section, with the aid of which a consumption measurement can take place. Specifically, a pressure difference measurement is used, which can also be evaluated in a time-shared manner. Complementary in the cited published specification explains that various flow resistances in the form of orifices or nozzles can also be built into the pipes in order to bring about an artificial pressure increase at or after the flow resistances.

With regard to the prior art, reference is also made to FR 2 467 388, which discloses a Venturi nozzle as an orifice, which is provided in the area of sensors, the sensors being switched in the manner of a measuring bridge.

DE 43 08 313 AI describes a device for determining the flow rate of a fluid medium according to the differential pressure principle. There it is emphasized that the required differential pressure at a throttling point can be generated by a narrow flow cross-section within a short distance, which, however, leads to very narrow cross-sections when the smallest flow rates have to be determined, with the result of possible blockages in the differential pressure line.

From the prior art explained above, however, it is only known to use the differential pressure measurement for the purpose of determining the consumption of liquids. No suggestions can be found in the known solutions for using a method for this in order to actually determine the leak, taking into account even very strong pressure fluctuations resulting from normal consumption.

The state of the art also includes DE 198 14 903 C2, relating to a method for preventively shutting off a supply line for a medium depending on the consumption habits of the user and pressure measurement in the lines, and DE 197 06 564 AI, directed to a leak water Detection and stop device for the household.

With regard to DE 197 06 564 AI, which is to be rated as generic, a differential pressure measurement with downstream processor-assisted pressure evaluation is used there. Consider the revelation according to DE 197 06 564 AI, it should be noted that a shut-off command is triggered when a predetermined water outlet is exceeded. So there is no special leak determination. On the contrary, it is proposed to provide a further flow meter which records the water consumption, the measurement data of which in the control device should enable an assessment of true leaks.

From the above, it is therefore the object of the invention to provide a further developed method for the active monitoring of pipelines which carry pressurized fluid media, as well as consumers connected to the respective pipeline or the piping system, with the principle known per se Differential pressure measurement is used. The process to be created should therefore offer the possibility of an entire pipeline system, e.g. in a residential building with several very different connected

To monitor consumers, fittings, lines and so on, while at the same time there is the possibility of If an accident is detected, the pipeline system carrying the fluid medium must be completely shut off.

In addition, it must be ensured that an arrangement for active monitoring based on the method can be produced inexpensively and can be assembled with reasonable effort, without there being any disadvantageous consequences for the flow conditions in the system when operating a system which has been supplemented according to the invention.

The object of the invention is achieved as defined in claim 1, the subclaims containing at least expedient refinements and developments.

Accordingly, it is preferably checked at or behind the transfer point between the supply device and the consumer connection, for example the house connection, continuously or in predetermined cycles whether there is a permanent and almost constant consumption over a predeterminable period of time. In this case, an abnormal condition For example, a leak is concluded and an alarm is triggered and / or the downstream piping system is shut off.

In the leak determination mode, a valve provided at or behind the transfer point is closed, so that the downstream piping system is shut off at least for a short time. In this state, the current input pressure is determined and saved. The pressure drop is then determined using the stored inlet pressure value and the measured outlet pressure, and a check is carried out to determine whether the specific pressure drop per unit of time exceeds a predetermined value, from which a fault in the piping system is concluded.

In the so-called tap operation, the aforementioned valve is opened at or behind the transfer point and changes in the pressure differences between the pressure values upstream and downstream of the valve are recorded.

If the pressure difference values no longer change over a predetermined period of time, the operating modes are changed.

Basically, there is a permanent change between leak determination mode and tap mode, the change being triggered as a function of determined pressure fluctuations, caused by consumer tap points. As a rule, the aforementioned change of the individual modes takes place several times within an hour.

The alarm message or the alarm forwarding can be carried out via a public telecommunications system or a radio signal. It is conceivable here to connect the alarm device to a GSM dialing device or to an arrangement connected to the fixed telephone network.

The ascertained error values from the leak determination mode are stored, the alarm being triggered and / or the system being shut off when the sum of the errors which are added up in the memory exceeds a threshold value. In the case of the operation of consumers with intended long, continuous media removal, for example for garden irrigation, a volume flow-varying element is used, this element changing the flow rate caused by the consumer periodically or stochastically.

On the arrangement side, for the active monitoring of pipelines that carry pressurized fluid media, as well as of consumers connected to the respective pipeline or the piping system, by means of pressure difference measurement at or behind the transfer point between the supply device and the consumer connection, a series circuit comprising a first pressure sensor, an electrically or hydraulically actuable one Valve and a second pressure sensor are provided, control electronics being connected to the pressure sensors and the valve actuating device in order to provide an error signal when the pressure drop per unit of time is detected after a controlled valve shut-off.

The valve used can be a pneumatic valve or a solenoid valve with manual override, the pressure sensors being able to be designed as piezo sensors.

The control electronics used to implement the method include a processor, an operating unit, a power supply and interfaces for connectable peripherals. To avoid problems during a power failure, the power supply can be buffered via secondary elements, i.e. In this case an uninterruptible power supply is provided.

The invention is based on the consideration that permanent and constant water consumption per time can represent an error in the monitored system.

To start up the arrangement according to the invention, the operator is first asked to close all water tapping points. After that, the intended valve opens and a system calibration instead. Offset errors of the sensors used and conversion errors are compensated for in this step.

The same applies to pressure fluctuations, given by the sensor distance and the natural fluctuations in the supply pressure caused by consumers outside the monitored system or by the water supplier itself.

Optionally, the tightness of the overall system can now be checked.

After closing the valve, the minimum pressure drop over a specified period of time is determined. Such a minimal pressure drop is given, for example, by dripping taps or by toilet cisterns.

In a next step, a maximum water consumption with the longest same flow rate is saved. For this purpose, the bathtub is filled completely, for example, or there is a defined time limit.

The valve is then opened and the arrangement according to the invention determines the maximum period of time that a consumer requires without changes.

In tap operation, the valve is open and the pressure difference measured across the gap valve is determined. In this mode, only the changes in the pressure difference are used. If the pressure difference has not changed during the previously determined maximum period of time, there is either no consumer or a permanent consumer and the system automatically switches to another operating mode.

Leakage determination is initiated by shutting off the water supply using a valve. Furthermore, the current inlet pressure is stored here, which is a more precise measurement of the pressure drop serves within the monitoring route, since external disturbances are no longer relevant.

When the valve is closed, the pressure drop, calculated from the stored inlet pressure and the measured outlet pressure, is compared with the minimum pressure drop per time. The minimum pressure drop per time was determined during commissioning when checking the tightness of the system.

If this pressure drop is exceeded per time, there is either a leak in the system or a consumer needs water for a longer period than was specified in the commissioning mode.

The result now obtained is recorded as a possible fault in the monitored system in a memory and the operation returns to the tap mode.

However, if the pressure drop per time is not exceeded, a correct condition is assumed and the fault memory is deleted. The system then goes into tap mode again.

As stated, there is usually a permanent change between the tap and the leak determination operation. This change, however, is not noticeable to the user, since the changeover is very quick and the pressure drops when switching on and off or when activating the valve are very small.

The respective status of the monitored piping system is stored in the error memory. If the leak search has ended several times with an error as a result and the total error sum exceeds a set value, a significant error within the monitored pipeline or the piping system is assumed. In this case, the valve is closed permanently and a user check or user intervention is necessary. To bypass the protective function, for example in the event of a fire or a device defect, a manual override on the valve is preferably provided in the form of a bypass.

The invention will be explained in more detail below using an exemplary embodiment and with the aid of figures.

Here show:

Fig. 1 is a diagram of the fluidics arrangement and

FIGS. 2 to 5 flow diagrams for the different operating or analysis modes of the arrangement according to the invention.

1, the arrangement for active monitoring of pipes between a house connection 1 and the water distribution 2 is e.g. looped into an apartment building.

The arrangement comprises a first pressure sensor A, which is followed by a solenoid valve 3 and a second pressure sensor B in the flow direction.

Piezoelectric pressure sensors are preferably used as pressure sensors A, B, which are active in the range between 0 and 6 bar and have a current output in the range between 4 mA and 20 mA, which can also be used for error detection.

An electromagnetic valve with indirect actuation and a manual adjustment option is used as valve 3.

The control electronics, not shown in the figures, is connected to the pressure sensors A, B and the solenoid valve 3 and comprises an arrangement of display, buttons and interfaces or connection options for peripheral electronics, for example for forwarding a known abnormal condition or for triggering an alarm. The control electronics implement the mode of operation explained in the flow diagrams according to FIGS. 2 to 5.

The description of the individual flow diagrams according to FIGS. 2 to 5 applies as an explicit disclosure essential to the invention, reference being made to the explanations there in FIGS. 2 to 5 in order to avoid repetition.

In the commissioning mode, there is first a request that all conceivable tapping points, i.e. possibly connected consumers, must be closed. Following an o.k. confirmation via an intended control keyboard of the control electronics, an opening of the valve 3 according to FIG. 1 is then initiated. The minimum and maximum values of the pressure sensors A and B are then determined, for example in a period of 5 minutes. These measured values are converted and stored in an internal system memory. These values are used to calculate the amount of the maximum gradient of the pressure difference between sensors A and B and to determine the mean values from the minimum and maximum values separately for each sensor. On the one hand, a filter constant and, on the other hand, a possible offset error are determined from these values.

If no leak test is necessary, system default values are used for further evaluation or further operation of the arrangement.

In the further step of commissioning, water consumption is triggered at the longest same flow rate or by using the specified time.

The system then determines the maximum amount of time that a consumer needs without change. At the end of this possibly repeated process, commissioning is ended and an internal system error counter is initialized. 4, the valve 3 is opened and the pressure difference measured above the valve is determined, only the changes in the pressure difference being relevant here. If, as shown in FIG. 4, the pressure difference no longer changes during the previously determined maximum period of time, either no consumer is connected or there is permanent consumption, in which case the leak determination operation according to FIG. 5 and the flow diagram shown there is passed over.

In the leak determination mode, the water supply is first shut off by means of valve 3 and the inlet pressure is measured and stored. After initializing the meter, the outlet pressure is determined. The stored inlet pressure minus outlet pressure then gives the desired and searched pressure difference. If the pressure difference is greater than a previously defined value, this is saved as an error status. At the same time, an intended error counter is incremented. If the error count is greater than 4, for example, an alarm is triggered. If this is not the case, the leak detection is defined as finished.

If the pressure difference is not greater than the predefined value, a further counter is used to check and measure the outlet pressure and then determine the pressure difference. According to the exemplary embodiment, this process can be repeated up to 120 times. When the maximum number of check routines has been completed, the relevant counter is set to 0 and the leak detection is declared finished, i.e. there is a transition to tap operation.

All in all, with the arrangement described above and the associated method, it is possible to set up monitoring of pipeline systems, which, in addition to the desired checking of all consumers and the entire pipeline, also creates the possibility of switching off the water supply at the transfer point of the device to be monitored, so that a possible damage successful can be prevented and thus water damage or high water consumption can be prevented with corresponding costs.

LIST OF REFERENCE NUMBERS

1 house connection

2 water distribution

A first pressure sensor B second pressure sensor

3 solenoid valve

Claims

claims

1.Procedures for the active monitoring of pipelines which carry pressurized fluid media, as well as of consumers connected to the respective pipeline or the piping system by means of differential pressure measurement, preferably being checked continuously or in predetermined cycles at or behind the transfer point between the supply device and the consumer connection, whether there is a permanent and almost constant consumption over a predeterminable period of time, in which case an abnormal condition, for example a leak, is inferred and an alarm triggering and / or shutdown of the downstream piping system takes place, characterized in that an on or after the transfer point provided valve shuts off the downstream piping system, the currently existing inlet pressure being determined and stored, and thereafter the pressure drop using the stored E Inlet pressure and the measured outlet pressure is determined and then checked whether the specific pressure drop per unit of time exceeds a predetermined value, from which a fault in the piping system is concluded.

2. The method according to claim 1, characterized in that a valve provided at or behind the transfer point is or is opened in the tap operation and changes in the pressure difference of the pressure values upstream and downstream of the valve are detected.

3. The method according to claim 2, characterized in that an operating mode change takes place when the pressure difference values no longer change over a predetermined period of time.

4. The method according to any one of claims 1 to 3, characterized in that a permanent change between the leak determination operation and tap operation is carried out.

5. The method according to claim 4, characterized in that the change is triggered as a function of determined pressure fluctuations, caused by consumer taps,

6. The method according to any one of the preceding claims, characterized in that the alarm message or alarm forwarding is carried out via a public telecommunications system or a radio signal.

7. The method according to claim 1, characterized in that the error values are stored, an alarm being triggered and / or the system being shut off when the error number exceeds a threshold value.

8. The method according to any one of the preceding claims, characterized in that a volume flow varying element is used for the operation of consumers with intended long, continuous media removal, this element changing the flow rate caused by the consumer periodically or stochastically.