EP3147577A1

EP3147577A1 - Device for and method of fluid flow monitoring

Info

Publication number: EP3147577A1
Application number: EP16190419.8A
Authority: EP
Inventors: Herman Frederik Van Rees; Johannes Antonius Maria Oortman; Henjo GROENEWEGEN
Original assignee: Stn BV
Current assignee: Ten Real Estate BV
Priority date: 2015-09-23
Filing date: 2016-09-23
Publication date: 2017-03-29
Also published as: NL2017519B1; NL2015496B1; NL2017519A

Abstract

A fluid flow monitoring method and a fluid flow monitoring device (10) comprising a fluid passage (18) having a fluid input (13) and a fluid output (15), a fluid flow detection device (19, 20, 24, 25, 27) arranged for detecting fluid flow through the passage (18), and an electronic control circuit (23). The electronic control circuit (23) operatively connects to the fluid flow detection device (19, 20 24, 25, 27). The fluid flow detection device (19, 20 24, 25, 27) is arranged for establishing absence and presence of fluid flow through the fluid passage (18) and for providing signalling of an operational state of the fluid flow by operating presentation means (23) when a user is sensed in the vicinity of the fluid flow monitoring device (10).

Description

Field of the invention

The invention generally relates to fluid flow monitoring. More particularly, the invention relates to a fluid flow monitoring device and a method of fluid flow monitoring for indicating that a hazardous situation may occur in relation to a pathogen infection such as a Legionella infection.

Background

Aquatic systems, like hot-water tanks inside or outside a building, cooling towers, and evaporative condensers of large air-conditioning systems, such as those commonly found in hotels and large office buildings, thermal water systems including hot tubs and spas but also water supply pipes at home, pipework of water distribution systems in apartment buildings, hotels and other public buildings, for example, are sources that allow Legionella bacteria to thrive.
Legionella are natural inhabitants of water found in both potable and non-potable water systems and may cause the so-called Legionnaires' disease or Legionellosis which is a severe, often lethal, form of pneumonia. Pathogenic Legionella species thrive at water temperatures between 25 and 42°C with an optimum temperature of 35°C.
To prevent Legionella infection, the recommended temperature for storage and distribution of cold water is below 25°C, and ideally below 20°C. However, Legionella may survive for long periods at low temperatures and may proliferate when the temperature increases, if other conditions allow. As 20°C is at room temperature, there is a risk of Legionella proliferation in cold water supply pipes that remain stagnant at ambient temperatures in the room temperature range or above. A substantial risk of Legionella growth is found, however, in hot water pipes, the temperature of which may drop to about 40°C due to non-use during a longer period of time. Such as, for example, while being absent from home during holidays or in hotel rooms that are not booked for a longer period of time.
Legionella transmission is thought to occur via inhalation of aerosolized mist produced from Legionella contaminated water of the above-mentioned sources, for example, such as by showers, decorative fountains, humidifiers, respiratory therapy equipment, whirlpool spas, and the like.
Risk factors that may promote the proliferation of Legionellae include temperature, water quality, design of and the material used in construction of pipework and the presence of biofilms inside the pipes. Design, i.e. minimizing areas of stagnation and low flow, installation, management and maintenance of these water systems must be undertaken with control of microbial growth in mind. Disinfection, cleaning, monitoring and regular service and maintenance are key factors in controlling Legionella.
Besides disinfection of the water and water pipes, for example, Legionella pathogens are sensitive for temperatures above about 50°C. According to publications issued by the World Health Organization, temperature affects the survival of Legionella in that at temperatures above 70°C Legionella dies almost instantly and at 60°C 90% of the population die in 2 minutes. Accordingly, in the case of water systems at risk from stagnation, flushing the system with hot water at 55-60°C before use thereof, may be effective to substantially kill the lethal pathogens.
As a precautionary manner, before taking a shower, for example, it is recommended to flush the shower for a few minutes, such that hot water of a sufficient high temperature, preferably at or about 60°C, flows through the hot water pipe and thereby kills the pathogens. Flushing of the cold water pipe at the same time may reduce the amount of possible Legionella bacteria in the cold water tube. During flushing, one should avoid to inhale Legionella from the flushing water.
In many cases, such as a hotel room, the user normally does not know for how long the room has not been occupied, for example. Although it may become a habit to first flush the shower or bath before using same, many people are still not aware of the risks of legionella or simply may forget to flush the shower first.
For preventing the proliferation of Legionellae infection in a water piping system, several devices and systems have been proposed for artificially creating a fluid flow in the piping system, either or both based on lapsed time and ambient temperature measurement, for example.
European patent application EP 2 439 174 is an example of a completely automatically operating flushing or fluxing system, in which a controllable electrovalve has to be installed in the water piping as well as a by-pass drainage pipe for periodically draining water form the water piping system through the valve and by-pass drainage, thereby creating fluxing cycles at periodic intervals, for example.
A like system is know from European patent EP 2 166 159 , which proposes to automatically execute a toilet flushing for creating an artificial water flow in the piping system.
Besides the relatively high costs for the installation of such a solution and the relatively high amount of additional waste water caused by periodically creating a waste water fluid flow, a prominent disadvantage of this system is that the water fluxing is caused beyond any control or the presence of a user that can monitor malfunctioning of the system, which may cause a risk of flooding or the like. The system also lacks a direct signalling to a user about the actual operational state of the water piping system with respect to the risk of Legionella contamination.
European patent application EP 2 293 027 discloses a device for coupling with an existing water consumption meter at an inlet point of a water piping system. A potential risk of water contamination is derived from the amount of water supplied through the water consumption meter, i.e. the water dwell time in the system, and the water temperature, and is signalled by a remote alarm signal.
The device disclosed has the disadvantage of indicating a contamination risk based on the water dwell time in the piping system as a whole, which does not take into account potential contamination risk in terminating parts of the water piping system such as in hotel rooms, the bath room at home, etcetera where aerosolized mist is created that provides a high risk for Legionella infection.
German patent application DE 10 2007 009 007 discloses a water tap comprised of presentation means, such as a plurality of Light Emitting Diodes (LEDs), for indicating the flushing activity of the tap. The system continuously measures and stores water consumption or a tapped amount of water and the temperature thereof, for determining a potential risk of contamination of the water and continuously signals a save, a potential hazardous and a hazardous operational state of the water to be tapped from the water tap, causing a relatively high energy consumption requiring power supply from a mains power supply. This makes that the device, for electrical safety reasons, is not suitable for use in showers or the like.

Summary

It is an object of the invention to provide a device that assists users in determining whether to take precautionary measures to avoid becoming at risk of Legionella bacteria, such as when using aquatic systems producing aerosolized mist.
According to the invention, in a first aspect thereof, there is provided a fluid flow monitoring device, comprising a fluid passage having a fluid input and a fluid output, a fluid flow detection device arranged for detecting fluid flow through the passage, presentation means for indicating an operational state of the fluid flow and an electronic control circuit, operatively connected to the fluid flow detection device and the presentation means for determining and signalling an operational state of the fluid flow. The fluid flow monitoring device is arranged for being powered from an internal electric power supply and comprises an ambient proximity sensor for sensing user presence in the vicinity of the fluid flow monitoring device and operatively connected to the electronic control circuit. The control circuit is arranged for operating the presentation means for indicating an operational state of the fluid flow based on user presence sensed by the proximity sensor.
The fluid flow monitoring device according to the invention is designed as a stand-alone device not requiring an external power supply, for being installed in a fluid supply pipe or between a fluid supply pipe and a device producing aerosolized fluid mist, such that in use fluid flows through the fluid passage of the fluid monitoring device from its fluid input to its fluid output.
The device comprises presentation means for directly presenting a user with the operational state of the fluid flow through the device, thereby assisting users objectively in determining whether to take precautionary measures to avoid becoming at risk of Legionella bacteria, such as flushing fluid for a period of time through a drain before producing aerosolized mist from the fluid, in case of an indication of a hazardous or potential hazardous situation, for example. As this flushing is initiated by and under control of a user, the risk of flooding or other trouble in case of malfunctioning, such as with a clogged drainage for example, is greatly eliminated compared to automatic flushing system operating without user surveillance.
With the device according to the invention, flushing of waste water will only be applied when there is a risk of infection of the user when using the water system. As indicated in the background part above, Legionella dies almost instantly and in the case of water systems at risk from stagnation, flushing the system with hot water at 55-60°C during a short time, such as 1-2 minutes, for example, before use thereof, appears effective to substantially kill the lethal pathogens. It will be appreciated that, compared to automatic preventive flushing systems, the invention effectively reduces the amount of waste water to the extent that is really necessary for sanitizing the water piping.
The incorporation, in the fluid flow monitoring device, of an ambient proximity sensor allows for both an effective signalling to a user when in the vicinity of the device and effectively reduces power consumption of the device, as same may be operated in a sleep mode or standby mode in the absence of a user. In such a sleep mode or standby mode of operation, power consumption can be reduced to the power consumption required for the proximity sensor to activate the control circuit when a user or potential user is sensed.
Proximity sensors suitable for the purpose of the invention and consuming just a little of a few micro-Watts are commercially readily available, such that the fluid flow monitoring device according to the invention may be powered from an internal or on-board electric power supply, such as a conventional battery, during a normal operational life time of a few years, such as 3-5 years for example, dependent on the energy capacity of the battery used. Accordingly, from a point of view of electrical safety, the device is not restricted in its use and may be safely applied in extremely wet environments, such as showers.
In an embodiment of the device according to the invention, the control circuit is arranged for establishing absence of fluid flow through the fluid passage and providing signalling based on a duration of the absence of fluid flow by the presentation means when sensing user presence by the proximity sensor. That is, the device provides signalling based on the time period that no fluid flow through the device is monitored.
Absence of fluid flow through the fluid flow monitoring device provides an objective indication of stagnant fluid in the fluid source and/or the fluid supply pipe to which the fluid flow monitoring device connects, and thereby an indication of the risk of Legionella growth in the stagnant fluid, while its duration can be established by an electronic timing circuit, such as digital clock circuit or a digital counter circuit, for example, in particular a timer or a counter that expires after a set time period, in favour of a very low power consumption.
In an embodiment, in particular for use with showers at home or in a hotel bathroom, for example, the fluid flow monitoring device comprises a water tight housing, a first end of which comprising the fluid input and an opposite second end of which comprising the fluid output, wherein the fluid input is arranged for connecting an output of a water tap or the terminating end of a water pipe and the fluid output is arranged for directly connecting a shower head or a water hose terminating in a shower head, for example.
Although the risk of becoming infected increases with the growth of the Legionella population, in an embodiment of the fluid flow monitoring device, the control circuit comprises a timing circuit arranged for providing signalling after lapse of a set or settable time period from detecting the absence of fluid flow. That is, signalling is provided when a Legionella population of a certain size providing a safety risk is assumed to have been built up, in the present embodiment expressed as an amount of time lapsed from detecting absence of fluid flow and during which fluid flow is continuously or substantially continuously absent, that is a maximum allowable stagnant fluid time.
This maximum allowable stagnant fluid time, i.e. this threshold, can be set by factory settings, for example, or being user settable. The term user in the present description and invention also implies a skilled person certified for installing the fluid flow monitoring device, for example. The actual amount of the allowable maximum fluid stagnant time depends, inter alia, on the risk factors that promote the proliferation of Legionellae in the fluid source or aquatic system to which the fluid flow monitoring device connects, as mentioned in the introductory part.
In an embodiment of the invention, for the purpose of reducing power consumption as much as possible, the control circuit is arranged for establishing presence of fluid flow through the fluid passage and interrupting signalling of the absence of fluid flow by the control circuit from detecting presence of fluid flow through the passage of the fluid flow monitoring device.
To assist users in determining the time during which flushing should be performed, for example, in an embodiment of the fluid flow monitoring device according to the invention, the control circuit is arranged for interrupting the signalling after lapse of a set or settable delay period. The duration of this delay period may be set by factory settings or being user settable. Again, the term user also implies a skilled person certified for installing the fluid flow monitoring device, for example.
The actual duration of the delay period depends, inter alia, on the type of the fluid source or aquatic system to which the fluid flow monitoring device connects, the total duration of continued absence of fluid flow, and the temperature of the fluid while flushing, for example. It will be appreciated that both the allowable maximum fluid stagnant time and the length of the delay period after monitoring presence of fluid flow by the fluid flow monitoring device may be set with a safety margin.
In an other embodiment of the fluid flow monitoring device according to the invention, the control circuit is arranged for establishing presence of fluid flow through the fluid passage and providing signalling of the presence of fluid flow by the presentation means when sensing user presence by the proximity sensor. In particular the control circuit is arranged for providing such signalling during a set or settable time period. This signalling of the presence of fluid flow deviates, of course, from the signalling of the absence of fluid flow.
In a further embodiment of the invention the fluid flow monitoring device comprises at least one of a fluid temperature sensor and an ambient temperature sensor, operatively connected to the control circuit, wherein the electronic control circuit is arranged for providing the signalling based on an output of a respective temperature sensors, in particular wherein said signalling is provided based on temperature measurements of individual supply fluids and temperature measurement of the outlet fluid flow.
The provision of such sensors assists in providing a more precise signalling, that is a more precise determination of the conditions leading to Legionella contamination. As explained in the background part, Legionella bacteria thrive dependent on the ambient temperature. Measuring the ambient temperature therefore may directly influence the signalling provided, such as determining the allowable maximum fluid stagnant time. Measuring of the fluid temperature assists in determining the length of the delay period, i.e. the flushing period after monitoring presence of fluid flow by the fluid flow monitoring device. As indicated in the background part, the time needed to substantially kill the lethal Legionella pathogens in the fluid decreases with increase of the fluid temperature above about 60°C. The control circuit may be arranged to set or adapt set time periods automatically dependent on the measured ambient and fluid temperatures as explained above.
In particular in the case of a mixed fluid flow, such as with a water tap mixing cold and hot water, by measuring the temperature of the cold water supply, the temperature of the hot water supply and the temperature of the mixed water flow at the outlet of the water tap, the relative amount of water or fluid that is delivered by each of the supplies can be calculated. Based on this calculation, the delay period is dynamically adapted to ensure that a sufficient amount of fluid is flushed from each of the supplies.
It will be appreciated that in each of the supplies of a mixed fluid device or fixture, a separate fluid flow monitoring device may be installed, such that the amount of flushing fluid for each supply is determined separately and/or wherein the delay period is adapted or based on the required minimum amount of fluid that has to be flushed from a particular supply in order to provide a safe signalling, for example.
The fluid flow monitoring device in a further embodiment of the invention comprises at least one of optical, acoustical and mechanical presentation means, operatively connected to the control circuit.
In an electric power consumption efficient embodiment of the invention, the optical presentation means comprise Light Emitting Diode (LED) devices, arranged for emitting light externally from an outer circumference of the fluid flow monitoring device housing. An example of acoustical presentation means is a buzzer arranged in the housing of the flow monitoring device, such as an electromechanical or piezoelectric beeper. An other example of acoustic presentation means are loudspeaker means for providing a recorded spoken message, such as an instruction, or a spoken alert, preferably in different languages, for example. Mechanical presentation means may comprise, for example, a mechanically operated flag or shutter exposing or hiding a safety mark at the circumference of the housing of the fluid flow monitoring device. LED lighting is most versatile and preferred for signalling purposes.
As indicated above, in order to signal whenever it is safe to use the fluid, for example after flushing the fluid through the drain, the control circuit may be arranged for controlling the presentation means for presenting the presence of the fluid flow based on interruption of the signalling of the absence of fluid flow. That is, after a delay time sufficient for flushing the Legionella contaminated fluid, the signalling may be interrupted, for example by switching off the LED lighting or by first changing colour of the lighting thereof, for example from Red to Green, before switching off the signalling. In the embodiment in which the presence of fluid flow is expressly indicated, the LED lighting may change from Red to Green through Yellow, for example.
For the purpose of the invention suitable ambient proximity sensors or detectors are commercially readily available and may be selected from so-called motion type proximity sensors comprising at least one of passive infrared sensors, optical reflection sensors, laser type sensors, radar type sensors and ultrasonic sensors, and/or ambient light sensors detecting user presence from igniting the lighting in a room where the fluid flow monitoring device is installed, such as a bathroom, and/or from noise or sound produced by a user, for example. Passive infrared sensors, for example, allow for user detection at a distance of, for example, 0.5-2 m while consuming very less power allowing for battery operation.
In an advanced embodiment of the invention, the control circuit of the fluid flow monitoring device comprises a programmable digital data processing circuit, having a data processing algorithm arranged for operating the presentation for providing signalling based on establishing one or both of absence and presence of fluid flow and control signals received by at least one control input of the control circuit, in particular control signals provided by the proximity sensors and/or any of the temperature sensors mentioned above.
The provision of digital data processing circuitry allows for further functionally and customization in controlling the signalling provided by the fluid flow monitoring device. In particular in combination with circuitry arranged for remote communication, such as a signal transmission circuit, operatively connected to the control circuit, for remote signalling of a determined operational state of the fluid flow through the fluid passage of the fluid flow monitoring device, and a signal reception circuit arranged for receiving remote control signals for controlling the control circuit. For saving energy consumption, the transmission and/or receiving circuitry are operated under the control of the electronic control circuit, such that operation thereof is activated only when the proximity sensor senses user presence.
It will be appreciated that the signalling provided, besides signalling in the form of user perceptible signals provided by the presentation means, may comprise electric pulses or other electric signals radiographically or optically transmitted by the transmission circuit of the fluid flow monitoring device and which signalling is received and processed by a remote device and converted into user perceptible signals at this remote device.
In an embodiment the fluid flow monitoring device additionally comprises a remote module or gateway having transceiver circuitry, arranged for being communicatively connected to the signal transmission and/or signal reception circuit of the fluid flow monitoring device, and further comprising data processing circuitry and input/output circuitry arranged for presenting a determined operational state of the fluid flow based on the signalling provided and at least one of optical, acoustical and mechanical presentation means of the remote module, and for controlling the control circuit based on control signals received by the remote module.
In an embodiment the remote module or gateway is provided with at least one of an ambient temperature sensor, an ambient motion sensor, an ambient light sensor and an ambient proximity sensor. Any or all of an ambient motion sensor, an ambient light sensor, an ambient proximity sensor and an ambient noise or sound sensor may assist in an efficient signalling by the fluid flow monitoring device and the remote module, for example only when user presence in the vicinity of the fluid flow monitoring device, i.e. an aerosolized mist producing device, is detected. User presence may be detected from motion of the user, igniting the lighting in a room where the fluid flow monitoring device is installed, such as a bathroom, and/or by noise produced by a user.
The remote module or gateway may be arranged at a distance from the fluid flow monitoring device, for example outside a bathroom in an apartment or hotel room equipped with at least one fluid flow monitoring device according to the invention. This allows, for example, flushing of a shower without requiring the presence of the user in the bathroom to watch the signalling provided. In the case of a hospital, a nursing home or a retirement home, or similar, the remote module may be located at a central control location, for example. The remote module may comprise a personal computer or laptop computer or tablet, for control and operational settings purposes.
The transceiver circuitry of the remote module may be arranged for being communicatively connected to a data communication network, for exchanging operational data based on the signalling of the fluid flow monitoring device. This provides, for example, central registration and watching services for alerting users whenever a hazardous situation may occur in relation to Legionella infection.
A suitable fluid flow detection device comprises at least one of:

a magnetic sensor arranged along the fluid passage and a fluid-moveable magnetic plunger arranged in the fluid passage, for detecting absence or presence of fluid flow through the passage based on a relative position of the sensor and plunger,
an acoustic sensor arranged along the fluid passage, for detecting absence or presence of fluid flow through the passage based on acoustic flow noise caused by the fluid flow,
a temperature sensor, arranged along the fluid passage, for detecting absence or presence of fluid flow through the passage based on a change in temperature caused by the fluid flow,
an optical gate arranged along the fluid passage, for detecting absence or presence of fluid flow through the passage based on interruption or scattering of light in the optical gate caused by the fluid flow,
a capacitive or inductive sensor arranged along the fluid passage, for detecting absence or presence of fluid flow through the passage based on detuning of a tuned capacitively or inductively coupled circuit caused by the fluid flow, and
a propeller driven electric generator, the propeller arranged in the fluid passage, for detecting absence or presence of fluid flow through the passage based on electric signal generated by rotation of the propeller caused by the fluid flow.

Detection devices of the type mentioned above are known to a skilled person and, accordingly, need no detailed explanation.
The control circuit of the fluid flow monitoring device is advantageously arranged and operated for controlling the supply of electric power from an on-board power supply, such as a battery, for supplying electric power to the control circuit and sensors, to minimise as much as possible power consumption by the fluid flow monitoring device. In the case of a fluid flow detection device comprising a propeller driven electric generator, the electric power of the generator produced during fluid flow may be used for charging the on-board power supply, such as a rechargeable battery.
In a second aspect, the invention provides a method of fluid flow monitoring by a fluid flow monitoring device, such as a fluid flow monitoring device disclosed above, the method comprising the steps of:

detecting absence of fluid flow;
calculating a fluid flow absent time;
if the calculated fluid flow absent time is longer than a maximum allowable stagnant fluid time and while sensing user presence:
- providing an alarm signal;
detecting presence of the fluid flow;
calculating a fluid flow present time;
if the calculated fluid flow present time is longer than a delay period:
- providing a safe signal.

The alarm and the safe signal may be provided as any type of signal, such as but not limited to an optically, acoustically or mechanically presented signal. The signalling may also be provided as a wireless radio signal, an infrared signal or the like, for remote signalling. The alarm signal is provided whenever user presence is detected. Likewise, the provision of the safe signal may also be made dependent on the detection of user presence.
As explained above, the duration of the maximum fluid stagnant time and the delay period may be set by factory settings or being user settable. The actual amount of the allowable maximum fluid stagnant time and the delay period depends, inter alia, on the risk factors that promote the proliferation of pathogens, such as Legionellae, in the fluid source or aquatic system to which the fluid flow monitoring device connects. In particular the ambient temperature and the fluid temperature of the fluid while flushing are important parameters.
In an embodiment of the method, at least one of the maximum allowable stagnant fluid time and the delay period are calculated based on at least one of a fluid temperature measurement and an ambient temperature measurement. It will be appreciated that both the allowable maximum fluid stagnant time and the length of the delay period after monitoring presence of fluid flow by the fluid flow monitoring device may be calculated with a safety margin. Fluid temperature measurement may be provided, for example, by the heating equipment used for heating the fluid, such as water heating equipment, like a gas fired boiler or an electric boiler, and communicated to the fluid flow monitoring device.
Fluid temperature measurement is generally present in commercially available heating equipment, such that only a communication facility with the fluid flow monitoring device and/or a remote module communicatively connected to the fluid flow monitoring device has to be installed. Modern heating equipment may already comprise a data communication facility for control purposes or the like and that may be used for communicating temperature measurement with the fluid flow monitoring device as well.
In a further embodiment of the method, the alarm signal is provided based on an ambient proximity measurement comprising at least one of an ambient motion measurement, an ambient light measurement, an ambient proximity measurement and an ambient noise or sound measurement. That is, the alarm signal is only provided when a person appears in the vicinity of the fluid flow monitoring device, for example enters a room in which the fluid flow monitoring device is installed, this to minimize power consumption of the fluid monitoring device.
In another embodiment of the method, the invention provides for remote signalling of alarm signal and the safe signal, for example accessible outside a room where the fluid flow monitoring device is installed and/or at a central monitoring facility.
The invention further provides a fluid fixture or appliance, in particular a water fixture, designed as a water tap or a shower head, the fixture comprising at least one fluid outlet for supplying fluid by the fluid fixture, wherein the fluid outlet comprises a fluid flow monitoring device arranged and/or operating as disclosed above. That is, the fluid flow monitoring device is an integral part of the fluid fixture.
The invention also provides a fluid fixture, in particular a water fixture, designed as a water tap or a shower head, the fixture comprising at least one fluid inlet for connecting a fluid supply, such as a water supply pipe, the at least one fluid inlet comprising an integrated fluid flow monitoring device arranged and/or operating as disclosed above. In case of a water fixture comprising a separate cold water inlet and a hot water inlet, in each of the inlets a fluid flow monitoring device may be arranged, forming an integral part of the water fixture.
The invention will now be explained in more detail with reference to the appended figures, which merely serve by way of illustration of the invention and which may not be construed as being limitative thereto. In the figures, like reference numerals denote identical parts or parts performing an identical or comparable function or operation.

Brief Description of the Drawings

Fig. 1 shows, in a schematic and perspective view, an embodiment of a fluid flow monitoring device according to the invention.
Fig. 2 shows, in a schematic and perspective view, the fluid flow monitoring device of Fig. 1, the housing of which being partly broken away.
Fig. 3 shows, in a schematic and perspective view, a section of the fluid flow monitoring device of Fig. 1 taken along the line III-III.
Fig. 4 shows a schematic front view of another embodiment of a fluid flow monitoring device according to the invention.
Fig. 5 shows a schematic side view of the fluid flow monitoring device of Fig. 4.
Fig. 6 shows, in a schematic front view, the fluid flow monitoring device of Fig. 4, the housing of which being partly broken away.
Fig. 7 shows a schematic top view of the fluid flow monitoring device of Fig. 4, the housing of which being partly broken away.
Fig. 8 sows an electric block circuit diagram of electronic control circuitry of an advanced embodiment of the fluid flow monitoring device according to the invention.
Fig. 9 shows a simplified flow chart diagram of the operation of a basic embodiment of the fluid flow monitoring device and method according to the invention.
Figs. 10, 11 and 12 show, in a schematic and perspective view, examples of water fixtures comprising a fluid flow monitoring device in accordance with the invention.

Detailed description

Fig. 1 shows an embodiment of the fluid flow monitoring device 10 according to the invention, in particular for use with showers at home or in a hotel bathroom, for example. The fluid flow monitoring device 10 comprises a water tight cylindrical housing having an upper or first housing part 11 and a lower or second housing part 12. A first end of the housing forms the fluid input 13 and an opposite second end of the housing comprises the fluid output 15. The fluid input 13 comprises an inner threading 14, arranged for connecting to an output of a water tap or the terminating end of a water pipe of shower or bath, for example. The fluid output 15 comprises an outer threading 16, arranged for directly connecting a shower head or a water hose terminating in a shower head, for example.
The fluid flow monitoring device 10 comprises on-board presentation means. In the embodiment shown, the presentation means comprise a transparent ring 17, arranged between the first housing part 11 and the second housing part 12. The transparent ring 17 cooperates with a plurality of Light Emitting Diodes, LED 28, shown in Fig. 2. The housing can be manufactured partly or as whole of a plastic material or metal, such stainless steel, for example.
Fig. 2 shows the fluid flow monitoring device of Fig. 1, in which the housing parts 11, 12 are partly broken away. The fluid input 13 and the fluid output 15 connect by a cylindrical fluid channel or passage 18. For detecting fluid flow through the fluid passage 18, in the embodiment shown, an elongated piston or plunger 19 is moveably arranged inside the fluid passage 18. That is the plunger 19 is moveable in longitudinal direction of the of the fluid passage 18 between the fluid input 13 and the fluid output 15 thereof. The plunger 19 may be manufactured from a suitable fluid resistant plastic or the like.
Between the fluid output 15 and an opposite end of the plunger 19 a helical spring 20 is arranged. The weight of the plunger 19 and the spring action of this helical spring 20 are designed such that in the absence of a fluid flow through the fluid passage 18, the plunger 19 is forced in a position at or near the fluid input 13 of the fluid flow monitoring device 10. The spring action of the helical spring 20 is further dimensioned such that when a fluid, such as water, flows through the fluid passage 18, the spring force acting on the plunger 19 by the helical spring 20 is counteracted, such that the plunger 19 is forced to be at or near the fluid output 15 of the fluid flow monitoring device 10, however not blocking the flow of fluid through the fluid passage 18. The helical spring 20 is manufactured from a material that is resistant to a particular fluid. In the case of potable water, for example, the spring 20 may be manufactured from stainless steel, for example.
The LEDs 28, optically cooperating with the transparent ring 17 for emitting light that is visible externally from the fluid flow monitoring device 10 electrically connect to a printed circuit board, PCB, 23 mounted in the first part 11 of the housing. In the embodiment shown, the PCB 23 comprises two battery holders 21, each containing a battery 22, such as a button-type or coin-type battery, for example, for powering electronic control circuitry (not shown) for controlling the signalling LEDs 28, a magnetic sensor 24 and a proximity sensor 29, such as a passive infrared sensor, mounted at the PCB 23. The proximity sensor 29 is arranged for sensing user presence in the vicinity of the fluid flow monitoring device 10.
Fig. 3 shows a section through the fluid flow monitoring device 10 in longitudinal direction thereof, along the line III-III in Fig. 1. The helical spring 20 is supported at one end thereof by a spring holder 26 mounted in the fluid passage 18 at the fluid output 15. With its other end the helical spring 20 is fixed to the plunger 19. The movement of the plunger 19 in the fluid passage 18 is limited by the spring holder 26, preventing the spring from being fully compressed, and thus preventing blocking of fluid flow, such as a water flow.
The magnetic sensor 24 cooperates with a permanent magnet 25 arranged inside the plunger 19. The magnetic sensor 24 and the permanent magnet 25 form one of many possible arrangements of a fluid flow detection device for establishing absence of fluid flow through the fluid passage 18.
A known type of magnetic sensor is, for example, a so-called reed switch. The reed switch is an electrical switch operated by an applied magnetic field. In its most common form, it consists of a pair of contacts on ferrous metal reeds in a hermetically sealed glass envelope. The contacts may be normally open, closing when a magnetic field is present, or normally closed and opening when a magnetic field is applied. The reed switch may be actuated by bringing a magnet in the vicinity of the switch. Once the magnet is pulled away from the switch, the reed switch will go back to its original position.
A so-called digital version of the reed switch are the MagnetoResistive sensor, MR, Integrated Circuits, ICs. MR ICs are ultra-sensitive devices that respond to either a magnetic North pole or South pole applied in a certain direction to the sensor and use a very low average current in the microAmpere range, such as around 1 µA.
In the embodiment of the fluid monitoring device 10 shown in Figs. 2 and 3, the plunger 19 is in the vicinity of the magnetic sensor 24 when no fluid flows through the passage 18, for example when a shower tap, to which the fluid monitoring device 10 is mounted, is closed. In this position the magnetic sensor 24 senses the presence of the permanent magnet 25, as schematically illustrated by the dashed magnetic field line 27 in Fig. 3. In the case of a reed switch or MR IC, the switch may be opened or inactive, providing a logical "zero" signal, for example.
When the tap to which the fluid monitoring device 10 connects is opened, by the fluid pressure acting on the plunger 19 from the fluid input 13 of the fluid flow monitoring device 10, the plunger 19 will be forced in the direction of the fluid output 15 and comes to rest at the stop element 26. The plunger 19 remains in this position as long as fluid flows through the passage 18. In this position, the permanent magnet 25 is away from, i.e. no longer in the vicinity of, the magnetic sensor 24, which sensor senses the absence of the permanent magnetic 25. In the case of a reed switch or MR IC, the switch may be closed or active, for example. When the fluid flow through the passage 18 stops, under the force of the spring 20, the plunger 19 returns to its position near the magnetic sensor 24, which as a result detects again the presence of the permanent magnet 25.
Accordingly, the magnetic sensor 24 is able to detect absence of fluid flow through the passage 18 based on the relative position of the sensor 24 and the plunger 19. In the present embodiment, the magnetic sensor 24 likewise senses presence of fluid flow in the passage 18 based on the relative position of the sensor 24 and the plunger 19. The absence and/or presence of a fluid flow may be measured electronically, i.e. the magnetic sensor 24 may trigger an electronic control circuit mounted at the PCB 23.
An other known type of magnetic sensor suitable for the purpose of the present invention is, for example, a micro-electromechanical based magnetic field sensor, MEMS. This is a small-scale device for detecting and measuring magnetic fields. Many of these operate by detecting effects of the Lorentz force. A change in voltage or resonant frequency may be measured electronically, for example. An other type of magnetic sensor is a so-called Hall-effect sensor. A Hall-effect sensor is a transducer that varies its output voltage in response to a magnetic field, which voltage variation is used to trigger an electronic control circuit.
Those skilled in the art will appreciate that other than a magnetic sensor type fluid flow detection may be used for the purpose of the present invention. In the fluid flow monitoring device 10 shown in Fig. 2, for example, the magnetic sensor 24 may be replaced by an optical gate sensor mounted at the PCB 23 and operating across, for example in radial direction, through an optical transparent window in the passage 18. Such that presence of the plunger 19 near the flow input 13 interrupts the optical gate, thereby indicating absence of fluid flow, while when the plunger 19 is at its position near the flow output 15, in the case of a fluid flow through the passage 18, the optical gate is no longer blocked, thereby detecting presence of fluid flow in the passage 18. Instead of interrupting an optical ray, the plunger 19 may operate to scatter light back to the optical sensor.
A capacitive sensor or inductive sensor may operate for proximity detecting of the plunger 19, in that the plunger triggers the capacitive or inductive sensor arranged along or across the fluid passage 18. For example, wherein the plunger 19 is made of or comprises a metal part that, dependent on the position of the plunger 19 in the passage 18, detunes a capacitively or inductively coupled circuit mounted at the PCB 23.
Other types of fluid flow detection devices may operate as an acoustic sensor mounted at the PCB 23, for example, and arranged along the fluid passage 18, for detecting absence or presence of fluid flow through the passage 18 based on acoustic flow noise caused by the fluid flow. A temperature sensor, mounted at the PCB 23 and arranged along the fluid passage 18, may detect absence or presence of fluid flow through the passage 18 based on a change in temperature caused by the fluid flow.
In another embodiment of the invention, a propeller driven electric generator is arranged in the fluid passage 18, for detecting absence or presence of fluid flow through the passage 18 based on electric signal generated by rotation of the propeller caused by the fluid flow. It will be appreciated that such a propeller driven electric generator may be used for charging the batteries 22, for example, when driven by a fluid flow.
The proximity sensor may be any of an ambient motion sensor, such as a passive infrared proximity sensor 29 or an optical reflection sensor, a laser type sensor, a radar type sensor, an ultrasonic sensor, and/or an ambient light sensor and an ambient acoustic noise or sound sensor.
Fig. 4 shows another embodiment of a stand-alone operative fluid flow monitoring device 30 according to the invention, among others also for use with showers at home or in a hotel bathroom, for example. The fluid flow monitoring device 30 comprises a water tight housing 31, that may consist of an upper or first housing part and a lower or second housing part, that may be detachably connected.
A first end of the housing 31 forms a fluid input 32 and an opposite second end of the housing 31 comprises the fluid output 33 of the device 30. The fluid input 32 comprises a swivel head, either a hexagon type swivel head 34 designed for being mounted by a spanner or the like, or a swivel head 35 for being operated by hand, arranged for connecting to an output of a water tap or the terminating end of a water pipe of shower or bath, for example. The fluid output 33 comprises an outer threading 16, arranged for directly connecting a shower head or a water hose terminating in a shower head, for example.
The fluid flow monitoring device 30 comprises on-board or internal presentation means which, in the embodiment shown, are comprised of two LEDs 28, and an on-board or internal proximity sensor 29. The housing 31 can be manufactured partly or as whole of a plastic material or metal, such stainless steel, for example.
The housing 31 has a flattened profile, such as can be viewed from the side view shown in Fig. 5 and the top view shown in Fig. 7. This flattened profile makes the device suitable for mounting to a water outlet close to a wall, for example.
Fig. 6 shows the fluid flow monitoring device 30 of Fig. 4, in which the housing 31 is partly broken away. The fluid input 32 and the fluid output 33 connect by a cylindrical fluid channel or passage 18, comprising a fluid flow detection device such as the magnetic sensor 24 cooperating with a permanent magnet 25 arranged inside the plunger 19 and spring 20, of the type described above in connection with any of the Figures 1-3 of the fluid flow monitoring device 10. For reasons of fluid tightness, so-called O-rings 38 are provided ate the outer ends of the housing 31, as shown by broken lines in Fig. 6
The LEDs 28 are arranged for emitting light that is visible externally from the housing 31 of fluid flow monitoring device 30 and electrically connect to a PCB 36 mounted in the housing. In the embodiment shown, the PCB 36 also connects the electric ambient proximity sensor 29 in the form of a passive infrared, PIR, sensor. The proximity sensor 29 is arranged such that its field of view extends from the housing 31. By the swivel head 34, 35, the fluid flow monitoring device 30 can be easily installed with the field of view, i.e. the detection angle or detection field, of the proximity sensor 29 pointing in a direction for optimally sensing user presence, for example directed towards a door of a bathroom or a shower door or the like.
The fluid flow monitoring device 30 further comprises a PCB 37 for supporting the electronic control circuit and other sensors as explained below in connection with Fig. 8. For stand-alone operation, a battery 39 is comprised in the housing 31, such as battery of the so-called ½AA type, for example.
It will be appreciated that the fluid flow monitoring devices 10, 30 may be provided at one or both ends with swivel heads 34, 35.
Fig. 8 sows an electric block diagram of electronic control circuit 40 of an advanced embodiment of the invention. The circuit 40 comprises an electronic processing circuit 41; a fluid flow detection device 42, operatively electrically connected to a control input 43 of the electronic processing circuit 41; presentation means 45, operatively electrically connected to a control output 44 of the electronic processing circuit 41; a timing circuit 46, such as an accurate and stable oscillator circuit, operatively electrically connected to a control input 47 of the electronic processing circuit 41; at least one electric fluid temperature sensor 48 and an electric ambient temperature sensor 49, both operatively electrically connected to a respective control input 50, 51 of the electronic processing circuit 41, and an electric ambient proximity sensor 58, operatively connected to a control input 59 of the electronic processing circuit 41. The control circuit 40 is powered by a battery or batteries 22, 39 electrically connected at a power input 52 of the electronic processing circuit 41.
The sensors 48, 49 may be of any commercially available type. The fluid flow detection device 42 may be of the type described above in connection with any of the Figures 1-3, for example, such as the magnetic sensor 24 cooperating with a permanent magnet 25 arranged inside the plunger 19 and spring 20. The proximity sensor 58 may be any of an ambient motion sensor, such as a passive infrared proximity sensor 29, and/or an ambient light sensor and an ambient noise or sound sensor, of a commercially type. The electronic processing circuit 41 may comprise a digital data processing circuit, such as microprocessor, µP, and program memory storing program code for operating the data processing circuit.
The electronic control circuit 40, in the advanced embodiment shown in Fig. 8 further comprises a wireless transceiver circuit 55, comprising a transmitter, Tx, and a receiver, Rx, circuit for data exchange through any of a radio protocol, such as a short range radio communication protocol known as IEEE 802.11 WiFi or Bluetooth®, for example, or an Infrared or any other optical transmission technology. The wireless transceiver circuit 55 connects to a communication input/output 56 of the electronic processing circuit 41 and is arranged for being communicatively connected 57 to a transceiver circuit 61, Rx/Tx, of a remote module or gateway 60.
The remote module or gateway 60 further comprises a data processing circuit 62, such as a microprocessor µP and program memory storing program code for operating the data processing circuit 62, and input/output circuitry 63, operatively connected to the data processing circuit 62, and arranged for presenting absence of fluid flow signalled by the fluid flow monitoring device 10, 30. The input/output circuitry 63 may comprise optical, acoustical and mechanical presentation means. The transceiver circuit 61 likewise may operate in accordance with a short range radio communication protocol known as IEEE 802.11 WiFi or Bluetooth®, for example, or an Infrared or any other optical transmission technology.
The remote module or gateway 60 may further comprise a transceiver circuit 64, operatively connected to the data processing circuit 62 and arranged for operating a communication link 65, for example a WiFi or other wired and/or wireless communication link, among which a radio communication link of a commercial available cellular communication technology, for distance communication of the signalling provided by the fluid flow monitoring device 10, 30 with remote control equipment 66. In this way, the remote module 60 may operate as an intelligent gateway en may be used to program the electronic processing circuit 41, for example.
The remote module 60, when arranged geographically in the vicinity of the fluid flow monitoring device 10, 30, may instead of or in addition to the fluid flow monitoring device comprise an electric ambient temperature sensor 67, an electric ambient motion sensor 69, an electric ambient light sensor 71, an electric ambient motion sensor 73 and an electric ambient noise or acoustic sensor 75, all operatively electrically connected to a control input 68, 70, 72, 74, 76, respectively, of the data processing circuit 62. The sensors 67, 69, 71, 73, 75 may be of any commercially available type.
Reference numerals 53 and 54 indicate control settings which may be set at the fluid flow monitoring device 10, 30 or by the remote module 60, for example. The control settings 53, 54 may be arranged such that same are only accessible to a service person.
The circuit devices comprising the control circuit 40 enclosed by the box drawn in broken lines, may all be mounted inside the fluid flow monitoring device 10, 30 at the PCB 23 or PCBs 36, 37 thereof, for example. In an embodiment all or part of the control circuit 40 inside the box may be provided by a so-called Application Specific Integrated Circuit, ASIC, for example.
It is noted that in a basic embodiment of the invention, the fluid flow monitoring device 10, 30 comprises the electronic processing circuit 41, the fluid flow detection device 42, the proximity sensor 29, 58 the presentation means 45 and the battery or batteries 22, 39.
The presentation means 45, 63 may comprise one or a plurality of optical presentation means, such as LED 28, arranged for emitting light externally from an outer circumference of the device 10, 30 or the remote module 60. Other optical presentation means include displays for displaying messages, notifications, warnings and instructions, for example. The acoustical presentation means may also comprise buzzer arranged in the housing of the flow monitoring device, such as an electromechanical or piezoelectric beeper, or a loudspeaker, for providing spoken messages, such as an instruction, or a spoken alert, preferably in different languages, whether or not pre-recorded. Mechanical presentation means may comprise, for example, a mechanically operated flag or shutter exposing or hiding a safety mark at the circumference of the housing of the fluid flow monitoring device.
The principal operation of the control circuit 40 will now be explained with the aid of a flow chart diagram illustrating the operation of a basic embodiment of the fluid flow monitoring device and the method according to the invention. In the flow chart diagram 80 shown in Fig. 9, the direction of the flow is from the top to the bottom of the drawing. A different flow direction is indicated by a respective arrow.
The operation is assumed to start with block 81, "Start". In decision block 82, "Fluid flow absent?", the electronic processing circuit 41 detects whether or not the fluid flow detection device 42 detects a fluid flow through the fluid passage 18 of the fluid flow detection device 10, 30. While no fluid flow is detected, i.e. decision "Yes" of decision block 82, a fluid flow absent time is calculated in block 83, "Calculate fluid flow absent time". This fluid flow absent time may be calculated by the electronic processing circuit 41 from time pulses provided by the timing circuit 46, for example.
As long as the calculated fluid flow absent time does not pass a maximum allowable stagnant fluid time, i.e. decision "No" of decision block 84, "Fluid flow absent time > maximum allowable stagnant fluid time?" and fluid flow remains absent, the fluid flow absent time is continuously aggregated by the electronic processing circuit 41. Once the calculated fluid flow absent time is larger than the maximum allowable stagnant time, i.e. decision "Yes" of decision block 84, there may occur a potential hazardous situation as to the concentration of pathogens in the fluid source connecting to the fluid flow monitoring device 10, 30. Such as a risk of a hazardous Legionella population in the fluid source. Accordingly, the electronic processing circuit 41 provides an alarm signal as indicated by block 86, "Provide alarm signalling" whenever user presence in the vicinity of the fluid flow monitoring device 10, 30 is detected by the proximity sensor 58, i.e. decision "Yes" of decision block 85, "User present?". Otherwise, i.e. decision "No" of decision block 85, the device may operate in a standby mode, in which only the proximity sensor 58 and part of the electronic processing circuit 41 for controlling the proximity sensor 58 are operative, thereby effectively reducing power consumption of the fluid flow monitoring device 10, 30.
The alarm signal may be provided by the presentation means 45, under the control of the electronic processing circuit 41, such as by making one or a plurality of LED 28 emitting light in the colour red. This light emission may be a flash lighting, a running light, or other. Instead or in addition of the signalling by the presentation means 45, the alarm signalling may be transmitted by the Tx/Rx circuitry 55 to the remote module 60 and signalled by the circuitry 63 thereof and/or forwarded to a remote monitoring facility 66 for registration and alarming purposes, for example.
As long as fluid flow remains absent, i.e. decision "No" by decision block 87, "Fluid flow present?", and while user presence is sensed, i.e. decision block 86, decision "Yes", the alarm signalling remains. For minimizing power consumption of the battery 22, 39 of the fluid flow monitoring device 10, 30, the alarm signal is only shown by the presentation means 45, 63 when there is a person in the vicinity of the fluid flow monitoring device 10, 30, for example in the room where the fluid flow monitoring device 10, 30 is installed.
When fluid flow in the passage 18 of the fluid flow monitoring device is detected by the fluid flow detection device 42, i.e. decision "Yes" by decision block 87, a fluid flow present time is determined by the electronic processing circuit 41 as indicated by block 88, "Determine fluid flow present time". This fluid flow present time may likewise be calculated by the electronic processing circuit 41 from time pulses provided by the timing circuit 46, for example.
During this phase of the procedure, the fluid flow is not safe to use and need to be flushed, for example. In the case of a showerhead that connects directly or indirectly by a hose to the fluid flow monitoring device 10, 30 the user may drop the showerhead at or near the drain to flush the contaminated water. Otherwise the user has to leave the bathroom during the flushing, for example. One may also appreciate that the contaminated water may be directly flushed in that the control unit 41 controls a valve for directly flushing the contaminated fluid flow to the drain (not shown).
If the calculated fluid flow present time exceeds a delay period, i.e. decision "Yes" by decision block 89, "Fluid flow present time > delay period?", it is safe to use the fluid flow which is indicated by a safe signalling provide by the electronic processing circuit 41, block 90 "Provide safe signalling". The safe signalling may be provided, for example, by having the LED 28 of the presentation means 45 emitting green light. Likewise, the safe signalling may be communicated to the remote module 60 inside or outside a bathroom, such that a user gets an indication when sufficient water has been flushed. For energy saving reasons, the safe signalling may be switched off after a while or only be provided as long as a user is in the vicinity of the fluid flow monitoring device 10, 30, for example. At this stage of the flow diagram, in block 90 the fluid flow absent time may be reset for a new cycle, i.e. "Reset fluid flow absent time".
In the flow chart 80, as a precautionary measure, the safe signalling is only provided after the delay period has lapsed, i.e. decision "No" by decision block 89. In block 83, when fluid flow is again absent, the fluid flow present time is reset, i.e. "Reset fluid flow present time" and when in decision block 82 presence of fluid flow is detected, i.e. decision "No" thereof.
Those skilled in the art will appreciate that the control circuit 40 may operate in different modes for signalling the alarm or safe signals. When operating with a remote module 60, the steps of the flow chart 80 may be performed in the remote module 60, such that the fluid flow monitoring device 10, 30 just needs to signal the detection of absent of fluid flow without means for stand alone signalling, such as the presentation means 45. This will render the fluid flow monitoring device 10, 30 electrically even more energy efficient.
In the basic embodiment, wherein the fluid flow monitoring device 10, 30 comprises the electronic processing circuit 41, the fluid flow detection device 42 in the form of a reed relay or MR IC sensor 24 co-operating with the permanent magnet 25, the proximity sensor 29 and LED presentation means 28, a single lithium coin battery may power the fluid flow monitoring device 10, 30 for about 3-5 years. Using two batteries 22 or a battery having a larger capacity such as battery 39, this power lifetime will double. With special batteries, the battery lifetime of the fluid flow monitoring device 10 may be increased to about 15 years, for example.
In particular in the case of a mixed fluid flow provided by a fluid fixture, such as with a water tap mixing cold and hot water, before providing a safe signalling, it is important to ensure that a sufficient amount of water or fluid from each of the cold and hot water supply has been flushed. In a further embodiment of the fluid flow monitoring device according to the invention, plural temperature sensors 48 are provided, for measuring the temperature of the cold water or fluid supply, for measuring the temperature of the hot water or fluid supply and for measuring the temperature of the mixed water or fluid flow at the outlet of the water tap. The electronic processing circuit 41 is arranged for determining the relative amount of water or fluid that is delivered by each supply from a calculation of the supply fluid temperatures and the outlet fluid temperature. Based on this calculation the delay period can be dynamically adapted to ensure that a sufficient amount of fluid is flushed from each of the supplies.
Such a calculation may be arranged, for example, from a table stored in memory at the control circuit 40 or in the processing circuit 41. The inputs of this table are the measured supply and outlet fluid temperatures and the output is a time value of the delay period to be set for flushing the supplies or an adaptation factor of the delay period, for example. While flushing, the time value or adaptation factor may be periodically adapted, based on a periodic measurement of the supply and outlet fluid temperatures during flushing.
Of course, in each of the supplies of such a mixed fluid flow fixture a separate fluid flow monitoring device may be installed, and the delay periods of both supplies may be adapted based on the required minimum amount of fluid that has to be flushed from a supply in order to provide a safe signalling.
Fig. 10 shows an example of a fluid fixture designed as a water fixture or water tap 91, having a water outlet 92 for supplying water to a user and two water supply inlets 93, 94 for cold and hot water supply, respectively. In the outlet 92 of the water fixture 91, as an integral part thereof, a fluid flow monitoring device is arranged of the type disclosed above, such as a fluid flow monitoring device 30. The fluid flow monitoring device 30 may comprise a control circuit 40 having plural temperature sensors 48 for measuring the water temperature of each the cold and hot water supply 93, 94 and a temperature sensor 48 for measuring the outlet water temperature, and wherein the processing circuit 41 is arranged for calculating the delay period or flushing period based on the temperatures measured, such to ensure that a sufficient amount of water is flushed from each supply, prior to provide a safe signal. It is noted that the water tap 91 may comprise two separate fluid flow monitoring devices 30, one for each separate cold and hot water supply inlet 93, 94, respectively.
Fig. 11 shows an example of a fluid fixture designed as a shower head 95, comprising a water inlet 96 in which as a fluid flow monitoring device is arranged of the type disclosed above, such as a fluid flow monitoring device 30, forming an integral part of the shower head 95.
Fig. 12 shows an example of a fluid fixture designed as a water fixture or water tap 97, having a water outlet for supplying water to a user and at least one fluid or water inlet 99 for connecting a fluid supply, such as a water supply pipe. In the inlet part 98 of the housing of the water tap 97, as an integral part thereof, a fluid flow monitoring device is arranged of the type disclosed above.
It will be appreciated that the fluid flow monitoring device 10 disclosed above may likewise be provided with any of the fixtures shown. The fluid flow monitoring device 10, 30 may be shaped differently than shown, dependent on a particular design of a fluid or water fixture.
The invention is not limited to the embodiments disclosed and may be practiced in many other ways, without departing from the novel and inventive teachings as outlined in the appended claims.

Claims

A fluid flow monitoring device, comprising a fluid passage having a fluid input and a fluid output, a fluid flow detection device arranged for detecting fluid flow through said passage, presentation means for indicating an operational state of said fluid flow and an electronic control circuit, operatively connected to said fluid flow detection device and said presentation means for determining and signalling an operational state of said fluid flow, characterized in that said fluid flow monitoring device is arranged for being powered from an internal electric power supply and comprises an ambient proximity sensor for sensing user presence in the vicinity of said fluid flow monitoring device and operatively connected to said electronic control circuit, wherein said control circuit is arranged for operating said presentation means for indicating an operational state of said fluid flow based on user presence sensed by said proximity sensor.
The fluid flow monitoring device according to claim 1, wherein said control circuit is arranged for establishing absence of fluid flow through said fluid passage and providing signalling based on a duration of said absence of fluid flow by said presentation means when sensing user presence by said proximity sensor, in particular wherein said control circuit comprises a timing circuit arranged for providing said signalling after lapse of a set or settable time period from detecting said absence of fluid flow.
The fluid flow monitoring device according to claim 2, wherein said control circuit is arranged for establishing presence of fluid flow through said fluid passage, and for one of:
interrupting said signalling of said absence of fluid flow from detecting said presence of said fluid flow, in particular wherein said control circuit is arranged for interrupting said signalling after lapse of a set or settable delay period, and

signalling of said presence of fluid flow by said presentation means when sensing user presence by said proximity sensor, in particular wherein said control circuit is arranged for providing said signalling during a set or settable time period.
The fluid flow monitoring device according to any of the previous claims, wherein said presentation means comprise at least one of optical, acoustical and mechanical presentation means, in particular optical presentation means comprising at least one Light Emitting Diode, LED, arranged for emitting light externally from said fluid flow monitoring device.
The fluid flow monitoring device according to any of the previous claims, wherein said ambient proximity sensor is at least one of group comprising a passive infrared sensor, an optical reflection sensor, a laser type sensor, a radar type sensor, an ultrasonic sensor, an ambient light sensor, and an ambient noise sensor.
The fluid flow monitoring device according to any of the previous claims, comprising at least one of a fluid temperature sensor and an ambient temperature sensor, operatively connected to said control circuit, wherein said electronic control circuit is arranged for providing said signalling based on an output of at least one of said temperature sensors, in particular wherein said signalling is provided based on temperature measurements of individual supply fluids and an outlet fluid flow.
The fluid flow monitoring device according to any of the previous claims, wherein said control circuit comprises a programmable digital data processing circuit comprising a data processing algorithm arranged for operating said presentation means.
The fluid flow monitoring device according to any of the previous claims, comprising an internal power supply for supplying electric power to said fluid monitoring device.
The fluid flow monitoring device according to any of the previous claims, comprising at least one of
a signal transmission circuit, operatively connected to said control circuit, for remote signalling of a determined operational state of said fluid flow, in particular wherein said control circuit is arranged for operating said signal transmission circuit based on user presence sensed by said proximity sensor, and
a signal reception circuit arranged for receiving remote control signals for controlling said control circuit, in particular wherein said control circuit is arranged for operating said signal reception circuit based on user presence sensed by said proximity sensor.
The fluid flow monitoring device according to claim 9, comprising a remote module comprising transceiver circuitry, arranged for being communicatively connected to said signal transmission and/or signal reception circuit, and further comprising a data processing circuit and input/output circuitry arranged for presenting a determined operational state of said fluid flow based on said signalling by at least one of optical, acoustical and mechanical presentation means, and for controlling said control circuit based on at least one of control signals received by said remote module and provided by at least one of an ambient temperature sensor, an ambient motion sensor, an ambient light sensor and an ambient proximity sensor, operatively connected to said data processing circuit, in particular wherein said transceiver circuitry of said remote module are arranged for being communicatively connected to a data communication network, for exchanging operational data based on said signalling of said fluid flow monitoring device.
The fluid flow monitoring device according to any of the previous claims, wherein said fluid flow detection device comprise at least one of:
- a magnetic sensor arranged along said fluid passage and a fluid-moveable magnetic plunger arranged in said fluid passage, for detecting absence or presence of fluid flow through said passage based on a relative position of said sensor and plunger,

- an acoustic sensor arranged along said fluid passage, for detecting absence or presence of fluid flow through said passage based on acoustic flow noise caused by said fluid flow,

- a temperature sensor, arranged along said fluid passage, for detecting absence or presence of fluid flow through said passage based on a change in temperature caused by said fluid flow,

- an optical gate arranged along said fluid passage, for detecting absence or presence of fluid flow through said passage based on interruption or scattering of light in said optical gate caused by said fluid flow,

- a capacitive or inductive sensor arranged along said fluid passage, for detecting absence or presence of fluid flow through said passage based on detuning of a tuned capacitively or inductively coupled circuit caused by said fluid flow, and

- a propeller driven electric generator, said propeller arranged in said fluid passage, for detecting absence or presence of fluid flow through said passage based on electric signal generated by rotation of said propeller caused by said fluid flow.
The fluid flow monitoring device according to any of the previous claims, comprising a water tight housing, a first end of which comprising said fluid input and an opposite second end of which comprising said fluid output, wherein said fluid input is arranged for connecting an output of a water tap or a terminating end of a water pipe and said fluid output is arranged for directly connecting a shower head or a water hose terminating in a shower head, for example.
A method of fluid flow monitoring by a fluid flow monitoring device, said method comprising the steps of:
- detecting absence of fluid flow;

- calculating a fluid flow absent time;

- if said calculated fluid flow absent time is longer than a maximum allowable stagnant fluid time and while sensing user presence:
- providing an alarm signal;

- detecting presence of said fluid flow;

- calculating a fluid flow present time;

- if said calculated fluid flow present time is longer than a delay:
- providing a safe signal.
The method according to claim 13, wherein
at least one of said maximum allowable stagnant fluid time and delay period are calculated based on at least one of a fluid temperature measurement and an ambient temperature measurement, and/or
said alarm signal is provided based on an ambient proximity measurement comprising at least one of an ambient motion measurement, an ambient light measurement, and an ambient noise measurement, and/or
said alarm signal and said safe signal are provided remote of said fluid flow monitoring device.
A fluid fixture, in particular a water fixture, designed as a water tap or a shower head, said fixture comprising at least one fluid inlet for connecting a fluid supply and at least one fluid outlet for supplying fluid by said fluid fixture, and wherein at least one of a fluid outlet and a fluid inlet comprising a fluid flow monitoring device arranged in accordance with any of the claims 1 - 12 and/or operating in accordance with a method of any of the claims 13 - 14.