NL2019131B1

NL2019131B1 - Stoppage detector

Info

Publication number: NL2019131B1
Application number: NL2019131A
Authority: NL
Inventors: Dijksma Marieke; Adrianus Albertus Huibers Dirk; Tara Campagne - Sonneveld Sanne
Original assignee: Dijksma Marieke; Adrianus Albertus Huibers Dirk; Sanne Tara Campagne Sonneveld
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2019-01-07

Abstract

Legionella may cause Legionella pneumophila, an often-deadly decease. Legionella may spread and multiply in water at the right temperature to unacceptable levels. Especially water standing still in conduits may contain Legionella at such unacceptable levels. 5 Common options to prevent the build-up of Legionella in a conduit is either temporal heating, chemical or flushing. The most common used option for a network of conduits is flushing. Flushing all conduits requires quite some water. Especially, because all conduits will be flush regardless if they are frequently used or not. As a solution to the unnecessary spillage of water is a stoppage detector for 10 detecting a stoppage of a fluid in a conduit, comprising: a temperature sensor for measuring a temperature of the fluid; and processing means providing a stoppage detection signal based on the temperature of the fluid over time. 15 Figure 1

Description

FIELD OF THE INVENTION

The invention relates to the field of stoppage detectors for detecting a stoppage of a fluid in a conduit, a method for detecting a stoppage of a fluid in a conduit and a stoppage detection network for detecting a stoppage of a fluid in a conduit network.

BACKGROUND OF THE INVENTION

The genus Legionella is a pathogenic group of Gram-negative bacteria that includes the species L. pneumophila, causing Legionellosis. According to the World Health Organization (WHO), Legionellosis is a collection of infections that emerged in the second half of the 20th century, that are caused by Legionella pneumophila and related Legionella bacteria. The severity of Legionellosis varies from mild febrile illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires’ disease) that can affect anyone, but principally affects those who are susceptible due to age, illness, immunosuppression or other risk factors, such as smoking. Water is the major natural reservoir for legionellae, and the bacteria are found worldwide in many different natural and artificial aquatic environments, such as cooling towers; water systems in hotels, homes, ships and factories; respiratory therapy equipment; fountains; misting devices; and spa pools.

Several outbreaks of Legionellosis occurred in the past. These outbreaks had different fatality rates. One of the most fatal outbreaks was Bovenkarspel, The Netherlands, in the year 1999 with 32 fatalities. Preventing outbreaks of Legionellosis has become subject of legislation and regulation in many countries.

At temperatures between 20°C to 45°C Legionella will multiply. The ideal temperature range for multiplication of Legionella is between 32°C and 42°C. Legionella may develop in dead water or still water, or even not refreshed circulating water at the right temperature.

The prevention of outbreaks revolves around three options: temporal heating, chemical and flushing. Legionella is killed almost instantly if water, containing the Legionella is heated to a temperature over 70°C or for 2 minutes to a temperature over 60°C. Chemicals may be added to water to kill the Legionella. Typical chemicals used are Chlorine, Copper-silver ionization and Chlorine dioxide. As a third option, for pipe systems holding water, the pipes may be flushed to refresh the water held in the pipes. Flushing the pipes is typically repeated every week.

Flushing pipes requires a substantial amount of water. Especially, because the Legionella builds up along ridges and grooves of connections connecting the pipes. The amount of flushing is therefore dependent on the quality of the pipe system. The frequency of flushing is also dependent on the use of the pipe system. If a particular segment of the pipe system is often used, this segment doesn’t need to be flushed. But if a particular segment is not used frequently, this specific segment needs to be flushed regularly.

A disadvantage of the conventional method of flushing is that the amount of flushing is done independent of the use of the segment of the pipe system.

SUMMARY OF THE INVENTION

An object of the invention is to provide a stoppage detector.

According to a first aspect of the invention, a stoppage detector for detecting a stoppage of a fluid in a conduit, comprising: a temperature sensor for measuring a temperature of the fluid; and processing means providing a stoppage detection signal based on the temperature of the fluid over time.

A pipe system transporting a fluid may have a central entry point of the fluid. From the central entry point onward, the pipe system may branch in several pipes or conduits all leading to an exit point of the pipe system. Stoppage of a fluid in a pipe or a conduit may cause severe problems. For example, if the fluid is corrosive, the pipe may corrode too much during the stoppage of the fluid. As another example, if the fluid is water most of the time containing traces of Legionella, the Legionella in the water may multiply to unacceptable levels.

It is an insight of the inventors that in most pipe systems the fluid entering the pipe system has a first temperature and that the ambient temperature around the pipe system has a second temperature, wherein the first and second temperatures are different. As an example, a pipe system transporting water. The water entering the pipe system may have a temperature of ground water. Ground water is typically between 5°C and 15°C. The pipe system may be situated in a building or house. The ambient temperature of a building or house is typically 20°C to 25°C.

A further insight of the inventors is that during a stoppage of a fluid in a pipe system the fluid gradually changes temperature towards the ambient temperature of the local segment of the pipe. Typically, pipes carrying fluids, such as water, are made from metal, which conduct heat. This phenomenon is used in the current invention to detect from outside the pipe system if water inside the pipe segment or conduit local to the detector has a stoppage or is stationary in that pipe segment. This provides the advantage that a detector may be installed on the pipe system without the need for disassembling the pipe system for placing a stoppage detector inline with the pipe system. Hence, this detector provides the advantage of ease of instalment. Furthermore, the detector is simple and efficient.

A common way of avoiding negative effects of a stoppage, such as the build-up of Legionella in water encountering a stoppage, is flushing. Normally flushing of a conduit is done at regular times without regard to if a stoppage in the conduit has occurred or not and for how long. For example, if a conduit carrying water is frequently used, the need for flushing is minimal or even absent. This while a conduit carrying water that is not refreshed during a specified time interval needs to be fully flushed. The stoppage detector according to the invention provides a means of discriminating between conduits in need of flushing and conduits that do not need to be flushed or anything in between. Hence, the stoppage detector provides the further advantage of limiting or minimizing the amount of fluid needed to flush a conduit.

In an embodiment of the stoppage detector, the stoppage detection signal is solely based on one or more temperature measurements of the fluid. A system may be devised wherein other measurements are incorporated for providing a more accurate stoppage detection signal, while the elegance of the system is in its simplicity. Hence, excluding other type of measurements, such as other type of temperature measurements, provide the advantage of a simpler detector.

In an embodiment of the stoppage detector, it comprises an indicator for indicating a status of the stoppage detection signal. The stoppage detector may be used for detecting stoppage of water in a pipe segment. A typical reason for detecting the stoppage in a pipe segment is to assure the pipe segment is properly flushed for preventing the development of Legionella in the water of that pipe segment. This provides the advantage of having the stoppage detection signal shown locally to the personal that will flush the pipe segment. As an example, the stoppage detection signal may be shown on a smartphone via an app.

In a further embodiment of the stoppage detector, the indicator will also indicate the end of the need to flush the pipe segment. The stoppage detector may hold preprogramed information comprising parameters of the pipe segment, such as the amount of time to flush the pipe segment, the length of the pipe segment and/or the diameter of the pipe segment. Further, the processing means may indicate the absence of a stoppage in the pipe segment, thus indicating that the pipe segment is being flushed. This provides the advantage of limiting the amount of water needed to flush the pipe segment. It may even be that the pipe segment is used that much that there is no need to flush the pipe segment.

In an embodiment of the stoppage detector, the indicator is a visual indicator. Personal checking the pipe segments normally have to flush the pipe segment for a specified amount of time to refresh the water in the pipe segment and also to flush Legionella out from in grooves and behind ridges in the pipe. The personal doing this check is typically part of the cleaning staff. The cleaning staff mostly wear thick rubber gloves during cleaning. This prevents them from easily operating a smartphone or switch or handle on the device. Providing a visual indicator provides the advantage of improving allowing personal to continue their work, without the need that they need to take their gloves off.

In an embodiment of the stoppage detector, comprising a wireless communication unit for wirelessly communicating the stoppage detection signal. A detector is typically part of a network. As the detector is most likely used at a remote location, wireless communication prevents the need of wiring the detector.

According to another aspect of the current invention, a method for detecting a stoppage of a fluid in a conduit, comprising the steps of: measuring a temperature of the fluid; and providing a stoppage detection signal based on the temperature of the fluid over time. This method provides the advantage of a simple way of measuring a stoppage in a conduit. Furthermore, the method may be implemented in a simple device. Further, this method provides the advantage of an efficient way of measuring the stoppage in a conduit.

In an embodiment, the method comprises the step of comparing, wherein if the measured temperature is within an ambient temperature range, the stoppage detection signal is positive. The ambient temperature range may be predefined. The ambient temperature range may also be estimated based on historic measurements of the temperature of the fluid. The ambient temperature may be received from an outside source, such as a thermostat, another stoppage detector or another location where the method for detecting a stoppage of a fluid in a conduit is performed. This comparison provides the advantage of a clear and simple step for determining the status of the stoppage detection signal. In the case the ambient temperature range is adaptive, the embodiment provides the advantage of adapting the range to a fluctuating ambient temperature. The ambient temperature of the conduit may vary due to changes in day and night, thermostat setting and/or an open or closed window or door in the room comprising the conduit.

In an embodiment, the method comprises the steps of: measuring a central temperature of the fluid at a central distribution point of the fluid; and providing the stoppage detection signal also based on the central temperature. Typically, at a central location of the central distribution point, the fluid is least likely to have a stoppage. Thus, the central temperature will most likely be closer to the fluid temperature than the measurement at some branch downstream from the central distribution point. As the temperature of the fluid is known more accurately the occurrence of a stoppage in a conduit may be measured more accurately. Additionally, the thermal conductivity of the conduit may be estimated more accurately.

In an embodiment, the method comprises the steps of: subtracting the measured temperature from the measured central temperature providing a delta temperature; and comparing, wherein if the delta temperature is above a delta threshold, the stoppage detection signal is positive. This embodiment provides the advantage of an actual implementation of using the measured central temperature for more accurately detecting a stoppage of the fluid in the conduit. This embodiment also provides the advantage that it may form the bases for a calculation based on the delta temperature over time for using the change of the delta temperature as measure for the presence of a stoppage of the fluid in the conduit.

In an embodiment, the method comprises the step of indicating a status of the stoppage detection signal. This provides the advantage of indicating the need for flushing the conduit.

In an embodiment of the method, the step of indicating is visually indicating. This provides the advantage of visually indicating the need for flushing the conduit. Furthermore, this provides the advantage of cleaning personal not needing to take of their gloves, as described above.

In an embodiment, the method comprises the step of wirelessly communicating the stoppage detection signal. This provides the advantage of having the signal available at a remote location without the need for additional wires, as described above.

According to another aspect of the current invention, a stoppage detection network for detecting a stoppage of a fluid in a conduit network, comprising: a plurality of stoppage detectors arranged to a plurality of conduits providing a plurality of stoppage detection signals; and a central server receiving the plurality of stoppage detection signals for providing an overview of the stoppage detection signals. This provides the advantage of having stoppage detection signals available at a central location. This further provides the advantage that the plurality of stoppage detection signals can be combined to improve the accuracy of the stoppage detection throughout the network and/or at a local conduit. This further provides the advantage that the stoppage or use of the complete network may be estimated. This further provides the advantage that the central server may be connected to a remote location for remotely monitoring the stoppage status of the pipe or conduit network.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which:

Figure 1 schematically shows a perspective view of a conduit and a stoppage detector according to an embodiment of the current invention;

Figure 2 schematically shows a side view of a conduit and a stoppage detector according to an embodiment of the current invention;

Figure 3 schematically shows a cross-section of a conduit and a stoppage detector according to an embodiment of the current invention;

Figure 4 schematically shows a stoppage detection network comprising stoppage detectors according to an embodiment of the current invention;

Figure 5 schematically shows a stoppage detection network comprising stoppage detectors according to an embodiment of the current invention;

Figure 6 schematically shows a first method for detecting a stoppage of a fluid in a conduit according to the current invention;

Figure 7 schematically shows a second method for detecting a stoppage of a fluid in a conduit according to the current invention; and

Figure 8 schematically shows a test result of a test with a stoppage detector according to an embodiment of the current invention.

The figures are purely diagrammatic and not drawn to scale. In the figures, elements which correspond to elements already described may have the same reference numerals.

LIST OF REFERENCE NUMERALS

1	pipe, pipe segment or conduit
10	pipe network
11, 12, 13, 14, 15, 16	pipe segments of pipe network
16	pipe network entry point
17	pipe junction
20	non-return valve
21	pump
23, 24, 25, 26	valves
100	stoppage detector
101, 102, 103, 104, 105, 106	stoppage detectors of stoppage detection network
109	stoppage detection network
110	attachment means
120	casing
121	thermic isolation
125	indicator
126	visual indicator
130	thermal or temperature sensor
131	measured temperature
140	processing means
141, 141’	stoppage detection signals
150	central server
300, 301	method for detecting a stoppage
310	measuring fluid temperature
320	providing stoppage detection signal
330	receiving compensation information
340	compensating measured fluid temperature
350	indicating stoppage detection signal
a	distance between junction and stoppage detector
b	start flush conduit
c	first temperature drop start flush conduit
d	flush period
e	short stoppage in conduit
f	second temperature drop start flush conduit

Ill	cross-section indicator for figure 3

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following figures may detail different embodiments.

Figure 1 schematically shows a perspective view of a conduit 1 and a stoppage detector 100 according to an embodiment of the current invention. The stoppage detector comprises a casing 120 and attachment means 110. The attachment means attach the casing to the conduit.

The stoppage detector further comprises an indicator 125, preferably a visual indicator 126. The visual indicator may be a light, such as a LED. The visual indicator may indicate the need for flushing the conduit whereto the stoppage detector is arranged. The visual indicator may flash or continually light up when there is a need for flushing the pipe.

The visual indicator may switch off when the flushing is started. The visual indicator may also be reset, such as by a reset button. The visual indicator may also switch off only after enough flushing is done, therefore being an indicator of the amount of flushing needed to clear the conduit of possible build-up of Legionella in the conduit. If the visual indicator is providing a need for flushing as well as a stop for the need for flushing, the stoppage detector provides the advantage of limiting, such as minimizing, the amount of fluid needed for flushing.

Figure 2 schematically shows a side view of a conduit 1 and a stoppage detector 100 according to an embodiment of the current invention. Alternative labels for conduit are pipe or pipe segment.

The stoppage detector comprises a casing 120 and attachment means 110. The attachment means attach the casing to the conduit. The attachment means have the effect of pressing the casing, holding a temperature sensor, onto the conduit for creating a thermal contact between the temperature sensor and the conduit. The attachment means may be a hollow cylinder enveloping the conduit. The attachment means may be a clip for clipping the casing onto the conduit. The attachment means may comprise bias means for biasing, such as mechanically biasing, the casing onto the conduit. This provides the advantage of creating a thermal contact over a longer period of time. This provides the advantage of creating a thermal contact also if the shape of the conduit is slightly different by shaping, bending and/or indenting the casing. This advantage is improved by providing a flexible casing.

The casing, as stated above, comprises a temperature sensor for measuring the temperature of the conduit. If the stoppage detector is arranged to the conduit, the temperature sensor may be in contact with the conduit or in close proximity of the conduit for optimizing the thermal contact between the conduit and the temperature sensor. And, as conduits are almost always thermal conductive, measuring the temperature of the conduit is an indication of the temperature of the fluid inside the conduit.

As a typical example, the fluid may be water and the conduit is part of a pipe network or system of a building. A building may be a house, warehouse, storage, flat, high rise, skyscraper, elderly home, office building, industrial building, factory, hospital or the like, wherever a need for water is present. Stoppage of water in a pipe network may cause the development of unacceptable levels of Legionella in the pipe network. Hence, the need for a stoppage detector.

Water entering a pipe system has a first temperature. Further, the ambient temperature around the conduit may have a second temperature, wherein the first and second temperatures are different. Typically, the water entering the pipe system may have a temperature of ground water. Ground water is typically between 5°C and 10°C. The pipe system may be situated in a building or house. The ambient temperature of a building or house is typically 20°C to 25°C.

As the water flows through the pipe system, the water may exchange heat with the conduit and the conduit with the surrounding air of the conduit, which air has a temperature labelled ambient temperature. If a lot of water flows through the pipe system, the time during which the water may exchange heat with the air is limited, hence the temperature of the water will not change much and as a consequence the temperature of the conduit will be close to the water temperature.

As water encounters a stoppage in the pipe system, the water in the pipe system or a segment of the pipe system may stand still. During this stand still time, the water will continue to exchange heat with the air via the conduit. As a result, the temperature of the conduit will be close to the ambient temperature. It will be clear to the reader that the mechanism described above will apply to all fluids carried in a conduit, wherein the ambient temperature and the fluid temperature upon entry in the conduit are different. As an example, the ambient temperature is lower than the fluid temperature. As another example, the ambient temperature is higher than the fluid temperature.

The stoppage detector further may comprise the processing means. Alternatively, the processing means may be placed at a distance from the temperature sensor. The processing means receive the measured temperature of the temperature sensor. Typically, the processing means receive a measurement every 30 seconds from the temperature sensor. The processing means provide a stoppage detection signal based on the temperature of the fluid over time.

The processing means may use a threshold temperature. This threshold temperature may be selected to be a temperature between the range of the ambient temperature and the temperature of ground water. Depending on the circumstances these ranges may shift, and the threshold will be shifted as well as a result. Circumstances causing a shift may comprise ambient temperature, ground water temperature, inside temperature, outside temperature, time during the day, night-day cycle or time of year. As an example, a threshold may be set in the range of 10°C to 20°C, such as at 12°C, 15°C or 18°C.

The processing means may filter the temperature over time. The filter may be a higher order filter. The filter is preferably a high pass filter. As an example, a filter outputting a delta temperature, which is the difference between two consecutive temperature measurements. A change in delta temperature may indicate a change in the status of the fluid. For example, in the case of water as a fluid, a temperature drop may indicate a start of the flow of water. And a temperature rise may indicate a stoppage of water. A compensation may be implemented to compensate for ambient temperature changes influencing the measured temperature.

In case of a filter, the output of the filter may be compared to a delta threshold. The delta threshold may be in a range of 0.01 °C to 10°C.

The delta threshold may depend on the time interval between temperature measurements, accuracy of the measurements, the order of the filter and type of filter. Types of filters are low-pass, band-pass and high-pass filters.

Figure 3 schematically shows a cross-section of a conduit 1 and a stoppage detector 100 according to an embodiment of the current invention. The cross-section is along the plane III shown in figure 2 and in the direction of the arrows next to III in figure 2.

The stoppage detector comprises attachment means 110, a casing 120 and a thermal sensor 130. The attachment means attach the temperature sensor to the conduit for making a thermal contact between the temperature sensor and the conduit. The temperature sensor is placed in the figure at a distance of the conduit.

Alternatively, the attachment means may not be between the temperature sensor and the conduit, allowing the temperature sensor to come in direct contact with the conduit. Several embodiments of the attachment means are envisioned, as described above.

The casing comprises thermic isolation 121 for thermic isolating the temperature sensor from the ambient air for minimizing the direct influence of the ambient temperature on the temperature sensor. The thermic isolation may be flexible such that when pressure is applied by the attachment means that the thermic isolation shapes to the surface of the conduit.

Figure 4 schematically shows a stoppage detection network 109 comprising stoppage detectors 101, 102, 103, 104, 105, 106 according to an embodiment of the current invention. The stoppage detectors may be similar to each other and may be similar to the stoppage detectors described above.

The stoppage detection network is arranged to a pipe network 10. The pipe network comprises a first pipe 11 having an entry point 16 for fluid, such as water, to enter the pipe network. The first stoppage detector 101 is arranged to the first pipe to register a stoppage in the first pipe. The pipe network further comprises a non-return valve 20 arranged inline with the first pipe and preventing fluid from flowing towards the entry point.

As the pipe network is typically used to allow fluid to flow at least somewhere in the system, the first stoppage detector typically provides an indication of the temperature of the fluid entering the pipe network. The entry point may be labelled central distribution point. This temperature may be labelled as a central temperature. Alternatively, the first stoppage detector is arranged in a space, where the temperature is generally close to the temperature of the fluid entering the pipe network. Examples of such a space are at least partly underground or in a basement. Combining the temperature measurement of the first stoppage detector with the temperatures of other stoppage detectors allow for a more accurate stoppage detection signal.

The pipe network may further comprise a second pipe 12, which second pipe loops around providing a continues path for fluid to flow and is in fluid communication with the first pipe. The pipe network may further comprise a pump 21 arranged inline with the second pipe for pumping the fluid around. The pump may prevent the build-up of Legionella in one location of the pipe network by pumping around the fluid. As the fluid is pumped around and most likely the fluid at least somewhere leaves the second pipe, the flushing of the second pipe is evenly spread, thereby preventing the build-up of Legionella in one location.

The stoppage detection network further comprises a second stoppage detector 102 arranged inline with the second pipe for detecting a stoppage in the second pipe. Preferably the second stoppage detector is arranged in close proximity to the pump. More preferably the second stoppage detector is arranged to the pump, such that no pipe connection is between the second stoppage detector and the pump. The second stoppage detector may be used to detect the working of the pump. As the second stoppage detection signal is combined with control information of the pump, the combined information may show the working of the pump.

The pipe network further comprises a third, a fourth, a fifth and a sixth pipe

13, 14, 15, 16 branching off from the second pipe. The pipe network further comprises a third, a fourth, a fifth and a sixth valve 23, 24, 25, 26 arranged inline with respectively the third, the fourth, the fifth and the sixth pipe. The valves may be manually or automatically controlled valves for allowing fluid to flow through or be stopped in the respective pipes. For example, if the fluid is water, the valves may be a water tap, tap for a shower, a tap for a washing machine or the like. The stoppage detection network further comprises a third, a fourth, a fifth and a sixth stoppage detector 103, 104, 105, 106 arranged to respectively the third, the fourth, the fifth and the sixth pipe for detecting stoppages in the respective pipes. The third, the fourth, the fifth and the sixth stoppage detector preferably are arranged upstream of the third, the fourth, the fifth and the sixth valve respectively.

In case the stoppage detector is arranged downstream of the respective valve, the pipe may empty after the valve is closed. The pipe segment after the valve will contain air, such as ambient air, causing the conduit to adopt to the ambient temperature. Depending on the air circulation, this may be slower or quicker compared to a stoppage detector arranged upstream of the respective valve.

The fifth pipe branches of the second pipe at a pipe junction 17. As the fluid may circulate through the second pipe, if the fifth valve is closed, the fluid in the fifth pipe encounters a stoppage. But, if the fluid in the second pipe circulates while the fluid in the fifth pipe is stopped, the fluid in the fifth pipe near the pipe junction may still be influenced by the fluid temperature in the second pipe. This influence may have its effects on the temperature measurement of the temperature sensor. Therefore, the fifth stoppage detector is preferably arranged at a distance from the pipe junction. The distance is preferably more than a metre, less preferably more than half a metre, even less preferably less than 20 centimetres.

Figure 5 schematically shows a stoppage detection network 109 comprising stoppage detectors 101, 102 according to an embodiment of the current invention.

The stoppage detectors each comprise a temperature sensor 130 and processing means 140. The respective temperature sensors may be arranged to conduits for measuring respective temperatures of the conduits. The respective processing means receive a measured temperature 131 from a respective temperature sensor. The processing means may be arranged in close proximity to the temperature sensor. Alternatively, the processing means may be arranged at a distance of the temperature sensor. The measured temperature may be communicated between the temperature sensor and the processing means by a single wire, a bus, such as a local bus, or even wirelessly. Examples of wireless communication may be ZigBee, Bluetooth, Low energy Bluetooth, Z-Wave, WIFI, GPRS or the like.

The stoppage detection network comprises a central server 150. The respective stoppage detectors communicate stoppage detection signals 141, 141’ to the central server. The central server is typically positioned at some distance from the stoppage detectors. The central server may communicate wired or wireless with the respective stoppage detectors. Alternatively, the processing means may be arranged at a distance from the temperature sensor and local to the central server. For example, the processing means and the central server may use the same processor or computer system.

The central server may combine the different stoppage detection signals for providing an overview of the status of a pipe network, whereto the stoppage detection network is arranged. The pipe network may be a water supply, a water supply for cold water, a water supply for hot water, a central heating system, an air conditioning system, a heat pump system or combination.

A typical interval for the temperature measurements is 30 seconds. A typical interval for communicating the stoppage detection signal to the central server is 15 minutes. The processing means may therefore aggregate the temperature measurements for communicating the aggregated stoppage detection signals to the central server.

The central server or processing means may combine the temperature measurements of several stoppage detectors together to improve the stoppage detection. In case the processing means do the combining, the temperature measurement of another stoppage detector has to be communicated to the stoppage detector either directly or indirectly, such as via the central server. In case the central server means do the combining, the temperature measurement of the respective stoppage detectors has to be communicated to the central server as well.

Figure 6 schematically shows a first method 300 for detecting a stoppage of a fluid in a conduit according to the current invention. The method starts with the step of measuring 310 a temperature of the fluid. The method continues with the step of providing 320 a stoppage detection signal based on the temperature of the fluid over time.

Figure 7 schematically shows a second method 301 for detecting a stoppage of a fluid in a conduit according to the current invention. The method starts with the step of measuring 310 a temperature of the fluid.

Optionally, the method continues with the step of receiving 330 compensation information. The compensation information may be a measured temperature of another stoppage detector, a thermostat setting or ambient temperature measurement. The method continues with the step of compensating 340 the measured temperature based on the received compensation information. The received compensation information may comprise the ambient temperature and/or fluid temperature. The step of compensating may comprise the steps of subtracting the measured temperature from the compensation information for providing a delta temperature. The compensating step may comprise a step of filtering the compensation information.

The method continues with the step of providing 320 a stoppage detection signal based on the measured temperature of the fluid. The stoppage detection signal may be based on a comparison of the measured temperature with a threshold. The stoppage detection signal may be based on a comparison of the compensated measured temperature or the delta temperature with a threshold. The providing step may comprise a filtering of the measured temperature and/or the compensation information.

Optionally, the method continues with the step of indicating 350 a status of the stoppage detection signal. The status may be indicated visually, audibly and/or tactilely.

Figure 8 schematically shows a test result of a test with a stoppage detector according to an embodiment of the current invention. The vertical scale is in degrees Celsius, the horizontal scale is in intervals of 2 minutes.

The stoppage detector comprises a temperature sensor in thermal contact with a conduit. The conduit contains water. A valve downstream of the stoppage detector controls the stoppage of water in the conduit. If the valve is closed the water in the conduit is stopped. If the valve is opened the water in the conduit flows through the conduit.

The figure shows temperature readings of the temperature sensor over time. The figure shows a first stoppage period, a first flush period d, a second stoppage period, a second shorter flush period d and a third stoppage period.

The first flush period starts with a sudden drop in temperature c of 4.7°C in about 2 minutes time b. After the start time b the temperature change changes less over time.

During the first flush period d the valve is closed two times e for a short time interval of about 2 minutes. The sudden change in change in temperature readings is clearly shown.

The second flush period starts again with a sudden drop in temperature f of 5.3°C in about 2 minutes time b. After the start time b the temperature change changes less over time.

Further, at the end of the first flush period, when the valve is closed, the temperature rise is distinct.

During the second flush period d the valve is closed one time e for a short time interval of about 2 minutes. The sudden change in change in temperature readings is clearly shown.

As shown from this test data, an embodiment of the current invention may use the absolute temperatures for detecting a stoppage in the conduit. Alternatively, an embodiment of the current invention may use the slope of the temperatures for detecting a stoppage in the conduit, such as the start and end of the stoppage. As a further alternative, an embodiment of the current invention may use the change in the slope of the temperatures for detecting a stoppage in the conduit, such as the start and end of the stoppage.

In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the scope of the invention as set forth in the appended claims. For example, the shapes may be any type of shape suitable to achieve the desired effect. Devices functionally forming separate devices may be integrated in a single physical device.

However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ or ‘including’ does not exclude the presence of other elements or steps than those listed in a claim. Furthermore, the terms “a” or “an,” as used herein, are defined as one or as more than one. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles a or an limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases one or more or at least one and indefinite articles such as a or an. The same holds true for the use of definite articles. Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

Embodiments:

1. Stoppage detector (100) for detecting a stoppage or a fluid in a conduit (1), including:

- a temperature sensor (130) for measuring a temperature of the fluid; and

- processing means (140) providing a stop detection signal (141, 141 ’) based on the temperature of the fluid over time.

2. Stoppage detector according to embodiment 1, the stoppage detection signal is solely based on one or more temperature measurements of the fluid.

3. Stoppage detector according to embodiment 1 or 2, including an indicator (125) for indicating a status of the stoppage detection signal.

4. Stoppage detector according to embodiment 3. The indicator is a visual indicator (126).

5. Stoppage detector according to any of the 1-4, including a wireless communication unit for wirelessly communicating the stoppage detection signal.

6. Method (300, 301) for detecting a stoppage or a fluid in a conduit, including the steps of:

- measuring (310) a temperature of the fluid; and

- providing (320) a stop detection signal based on the temperature of the fluid over time.

7. Method according to embodiment 6, including the step of comparing, if the measured temperature is within a predefined ambient temperature range, the stoppage detection signal is positive.

8. Method according to embodiment 7, including the step of compensating (340) for ambient temperature changes based on the measured temperature.

9. Method according to any of the 6-8, including the step of compensating (340) for ambient temperature changes based on a temperature setting or a thermostat.

10. Method according to any of the 6-9, including the steps of:

- measuring a central temperature of the fluid at a central distribution point of the fluid; and

- providing the stoppage detection signal also based on the central temperature.

11. Method according to embodiment 10, including the steps of:

- subtracting the measured temperature from the measured central temperature providing a delta temperature; and

- comparing, where if the delta temperature is above a delta threshold, the stoppage detection signal is positive.

12. Method according to any of the any of the 6-11, including the step of indicating (350) a status of the stoppage detection signal.

13. Method according to embodiment 12, the step of indicating is visually indicating.

14. Method according to any of the 6-13, including the step of

5 wirelessly communicating the stoppage detection signal.

15. Stoppage detection network (109) for detecting a stoppage or a fluid in a conduit network (10), including:

- a variety of stoppage detectors (101, 102, 103, 104, 105, 106) arranged to a

10 various of conduits (11, 12, 13, 14, 15, 16) providing a variety of stoppage detection signals (141, 141 "); and

- a central server (150) receiving the various or stoppage detection signals for providing an overview of the stoppage detection signals.

CONCLUSIONS

A standstill detector (100) for detecting a standstill of a liquid in a line (1), comprising:

- a temperature sensor (130) for measuring a temperature of the liquid; and

- processing means (140) providing a standstill detection signal (141, 141 ') based on the temperature of the liquid over a period of time.

A standstill detector according to claim 1, wherein the standstill detection signal is based solely on one or more temperature measurements of the liquid.

A standstill detector according to claim 1 or 2, comprising an indicator (125) for indicating a status of the standstill detection signal.

The standstill detector of claim 3, wherein the indicator is a visual indicator (126).

A standstill detector according to any one of claims 1 to 4, comprising a wireless communication unit for wirelessly communicating the standstill detection signal.

A method (300, 301) for detecting a standstill of a liquid in a conduit, comprising the steps of:

- measuring (310) a temperature of the liquid; and

- providing (320) a standstill detection signal based on the temperature of the liquid over a period of time.

The method of claim 6, including the step of comparing, wherein if the measured temperature is within a predefined ambient temperature range, the standstill detection signal is positive.

The method of claim 7, including the step of compensating (340) for ambient temperature changes based on the measured temperature.

A method according to any of claims 6-8, comprising the step of compensating (340) for ambient temperature changes based on a temperature setting of a thermostat.

The method of any one of claims 6-9, comprising the steps of:

- measuring a central temperature of the liquid at a central distribution point of the liquid; and

- issuing the standstill detection signal also based on the central temperature.

The method of claim 10, comprising the steps of:

subtracting the measured temperature from the measured central temperature to provide a delta temperature; and

comparing, wherein if the delta temperature is above a delta threshold value, the standstill detection signal is positive.

A method according to any of claims 6-11, comprising the step of indicating (350) a status of the standstill detection signal.

The method of claim 12, wherein the step of indicating is visual indicating.

A method according to any of claims 6-13, comprising the step of wirelessly communicating the standstill detection signal.

A standstill detection network (109) for detecting a standstill of a liquid in a pipe network (10), comprising:

- a plurality of standstill detectors (101, 102, 103, 104, 105, 106) disposed on a plurality of lines (11, 12, 13, 14, 15, 16) that have a plurality of standstill detection signals (141, 141 ') provide; and

- a central server (150) that receives the plurality of the standstill detection signals for providing an overview of the standstill detection signals.

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