Patent Application
20140231531
The present invention relates to a gas delivery control system, in particular to a gas delivery control system for use in domestic environments. In particular the present invention relates to a gas delivery control system that provides for a reliable detection against small leaks as well as a rapid detection against larger leaks and that is simple in use and can be extended easily.
The present invention further relates to a gas delivery control method, in particular to a gas delivery control method for use in domestic environments. In particular, the present invention relates to an implementation by relatively simple means so as to encourage its implementation in domestic environments.
In particular gas leaks are responsible for serious accidents. Various systems are described that aim to timely detect gas leaks and to interrupt gas supply to avoid a hazardous situation.
For example so called gas leak switches are known that detect the presence of gas in a building and that cause a closure of a main gas valve.
As another example U.S. Pat. No. 5,866,802 describes a piping leakage detecting apparatus that includes a high pressure gas supply source, a gas implement connected to the high pressure gas supply source via a pipeline, and a switching device mounted on the pipeline for selectively opening and closing the pipeline. A pressure detecting device is mounted between the gas implement and the switching device for detecting the gas pressure inside the pipeline. A leakage judging device is provided to judge that gas leaks when no gas is being used and when a pressure drop is detected based on an output from the pressure detecting device, while the pipeline is being opened and closed by the switching device. A gas leak is judged if the predetermined pressure drop occurs in a time interval that is longer than a minimum time and shorter than a maximum time. In addition the apparatus may have non-use detection means that confirm a non-use of gas on the basis of an increase in the pressure in the pipeline.
U.S. Pat. No. 6,725,878 describes a gas leakage detection system that includes a flow path, a dual mode valve disposed in the flow path, an ultrasonic measuring section including a pair of ultrasonic transducers, disposed in the flow path upstream from the dual mode valve, a flow rate calculation section for computing a flow rate based on a signal from the ultrasonic measuring section, and a control section for controlling the dual mode valve. The control section closes or opens the dual mode valve instantaneously, and the flow rate calculation section computes a flow rate when the dual mode valve is closed. In an embodiment the gas leakage detection system includes a pressure sensor in addition to a flow rate sensor. The dual mode valve is closed if the detected flow rate is below a minimum value and during the closed state of the valve the leakage pressure is computed. On the basis of the slope of the pressure it is determined whether a leakage is present.
GB2373875 discloses an automated gas shut off system that may include a valve located in a conduit which supplies gas to appliances within a building, such as a boiler and a cooker. Sensors may be associated with the appliances and may include switches which close when a respective appliance is switched on and send signals to a CPU. The CPU then transmits these signals to the valve which opens and allows gas to be supplied to the appliances through the conduit. When the appliances are switched off, the signals from the sensors are terminated and the CPU signals the valve to close. In an alternative embodiment, a flow sensor and a programmable logic controller are used to control the supply of gas into a building.
U.S. Pat. No. 5,126,934 describes an automated gas distribution system for safely and reliably controlling the flow of gaseous fuel to gas appliances. The system implements a “closed-loop” delivery of gas, i.e., the gas is provided to a recognized appliance only when that appliance sends a valid request for gas to a control/communications subsystem. Certain conditions preclude the supply of gas despite a valid request for gas and include an appliance or system malfunction, or a command from the system operator instructing the system to ignore certain gas requests. In addition, emergency conditions, such as a fire or gas leak will also circumvent the closed-loop delivery of gas to appliances. In an embodiment, a pressure sensor is used to detect leaks in the gas distribution subsystem. The pressure sensor monitors the delivery pressure of gas through a home run line. The system is programmed to interpret a pressure drop in the line as a gas leak and respond in kind.
U.S. Pat. No. 7,210,495 discloses a safety valve system that includes a control valve connected to a gas meter and intersecting a gas flow path downstream of the gas meter and upstream of an entry point of a building. The control valve is adaptable between open and closed positions based upon received stimuli. A main gas supply line is mated to the control valve and includes auxiliary lines branching to appliances. A plurality of sensors is coupled in series to the appliances and is in communication with the control valve. A mechanism is included for transmitting a control signal to the control valve and for eliminating a fully charged gas line when the stimuli are detected by one of the sensors such that the control valve can allow and restrict gas flow to the appliances during operating and non-operating modes. Each of the sensors generates a unique control signal when the stimuli are detected.
It is noted that US2006/0283237 discloses a system for evaluating leaktightness applied to a gas storage device for storing high pressure fuel gas delivered from a filling station via a filler hose connected to the gas storage device. The system comprises a pressure-measuring device that is suitable for connection to the filler hose or to the pipework, a processor device for processing values measured by the pressure-measuring device, and a display device for displaying information supplied by the processor device. The device for processing values measured by the pressure-measuring device includes a device for controlling filling and for suspending filling of the fuel gas storage device from the filling station, a device for controlling the filling flowing rate, a clock, and a unit for comparing the measured pressure relative to predetermined thresholds Si during periods in which filling is suspended.
It is noted that EP1205704 discloses a method that involves determining the instantaneous value of a parameter representing the instantaneous state of filling of a vehicle fuel tank during a gas filling using a temperature sensor and a pressure sensor which are arranged in the vehicle fuel tank. In an embodiment this value is compared with a value determined by a sensor built in the tank. A difference is greater than a threshold may indicate a leakage or an improper functioning sensor.
DE2916550, also published as U.S. Pat. No. 4,269,061 discloses a method wherein a fluid pressure passageway such as a high pressure fuel line in a fuel injection system is pressurized to an upper predetermined value. Then, the passageway is isolated and the length of time for the pressure to drop to a lower predetermined value is measured. The greater the degree of leakage, the shorter the measured length of time. An alarm is energized when the measured length of time is shorter than a predetermined length of time.
JP08-313322 discloses a method for leakage detection in downstream pipeline between a gas meter and a gas appliance. In the known method a gas valve at the output of the pipeline is closed and subsequently a gas shut off valve is temporarily opened to even the gas pressure in the downstream pipeline with the gas pressure in a pipeline upstream with respect to the gasvalve. A gas leak is determined if a pressure reducing rate after closure of the gas shut-off valve is a prescribed level or higher. The gas-appliance has no function in the leakage detection procedure.
WO0169340 discloses a bottle containing liquefiable gas stored under pressure that is supplied to one or more appliances via a regulator and a conduit. Sensing means are provided that include a gas pressure sensor and a remote temperature sensor. Additionally a monitor is provided that contains a micro processor and indication means having a leak test mode. The leak test is performed by opening valve to fully pressurize the gas system, then closing valve and then switching the processor to a leak test mode. Once in leak-test mode the monitor monitors after a predefined fixed period of time whether the pressure held within the system has fallen below a predetermined minimum.
U.S. Pat. No. 5,440,477 discloses a modular bottle-mounted gas management system including computer-controlled valves, actuators, regulators and transducers. The system constantly also provides self-diagnostic and leak-checking functions.
US20060289559 discloses a CO2-based beverage dispensing system includes a CO2 monitoring unit operative to emit a warning upon detecting excessive consumption of CO2 gas. The CO2 monitoring unit includes a gas input port, a gas output port, a CO2 monitor, an alarm, and in one embodiment a shut-off valve. The CO2 monitor may measure CO2 gas flow rate or pressure, and indicate excessive CO2 gas consumption if the measured CO2 gas flow rate is above a predetermined flow rate or the measured CO2 gas pressure is below a predetermined pressure level.
DE10244139 (A1) discloses a safety system for a test installation for a hydrogen converting device. Accordingly a transport device or pump is controlled by a controller so that its hydrogen throughput is matched to the consumption of the hydrogen converter. The controller also compares a hydrogen transport parameter determined between the transport device and the converter with a parameter synchronized with the hydrogen consumption. If a difference threshold is exceeded, hydrogen supply is immediately switched off.
Despite the fact that these kind of systems reduce the risk of accidents related to gas leaks, their domestic use is not seen or at least not widespread.
It is a first object of the present invention to provide an arrangement of a gas delivery control system and one or more appliances including a central heating installation, in particular a gas delivery control system that can be implemented by relatively simple means so as to encourage its implementation in domestic environments.
It is a second object of the present invention to provide a corresponding gas delivery control method, in particular a corresponding gas delivery control method.
It is recognized by the inventors that the existing systems are unnecessary complicated and expensive, therewith prohibiting a wide implementation.
According to a first aspect of the present invention there is provided an arrangement of a gas delivery system and one or more appliances including a central heating installation, the one or more appliances being arranged for generating a request signal (S1) indicative for a requested supply of gas by at least one of the appliances, wherein the arrangement comprises,
The present invention provides an until now not recognized arrangement of features that enables a simple, effective and reliable detection of gas leaks, in domestic environments. None of the cited documents discloses this arrangement.
The arrangement according to the present invention, although requiring only modest means, can very well be combined with other safety and control systems.
For example, it is expected that in the near future more sophisticated gas meters (smart gas meters) will come into use, that will offer functionalities that can be shared with the gas delivery control system according to the present invention. Examples of these additional functionalities are remote control, reading out and inspection of the gasmeter (this applies analogously to electricity meters and heat delivery meters). These developments result in a better user comfort and energy management both for the consumer as the supplier of the delivered product such as gas, electricity or heat. For the consumer this means a better overview of the consumed product and a saving of energy. Furthermore, as the smart gasmeter can be read-out and inspected remotely it is not necessary to stay at home to wait for an employee of the supplier to do the inspection/readout. Neither does the consumer himself need to read out the meter. For the supplier this is advantageous in that charging can take place fully automatically and that the supplier can remotely connect/disconnect the consumer.
Also advanced gas appliances become available with increasing functionality to improve user friendliness, compactness, reduction of energy and facilitation of installation and maintenance. Also these functionalities can be combined with the arrangement according to the present invention. The present invention additionally offers various optional features that enable a smooth transition towards a fully functional implementation in domestic environments.
By integrating the arrangement according to the present invention with such a smart gas meter and/or an advanced gas appliance it is possible to realize the arrangement at even lower costs.
Integrating the arrangement according to the present invention with further Apps enables a further contribution to safety.
According to a second aspect of the invention also a gas delivery control method is provided that comprise the steps of
The error signal may be used in several ways. In an embodiment the gas delivery control system may be coupled to an internal or external alarm centre for reporting a status of the gas delivery control system to said alarm centre. The alarm centre may subsequently send an engineer to determine the cause of the error-message if this is not yet clear from the error-message itself and to carry out the necessary repairs.
In another embodiment the gas delivery control system is coupled with a communication system to enable reporting the presence of an error signal to another party involved, e.g. the owner of a residence where the gas delivery control system is installed. In an embodiment the communication system is an addressable communication system, such as a public phone system. In this way the gas delivery control system may report the status, i.e. the presence of the error signal to one or more addressees, for example by a text or a voice mail message.
In another embodiment the gas delivery control system comprises blocking means for blocking the controllable valve in a closed state upon delivery of the error signal.
This embodiment obviates the use of a gas leakage switch as described in the introductory portion. In this way the delivery of gas is prevented until the blocked state of the system is cancelled by an authorized person, so that a further leakage of gas is prevented. The blocking means may be combined with error signaling means in the embodiments described before. In a particular one of such combination the gas delivery control system has an auxiliary control module with a timer (time delay element) that postpones a blocking of the controllable valve for a predetermined time interval. This gives an entity, for example an employee of the alarm centre the opportunity to confirm that the system will be checked and repaired if necessary and, if that is considered acceptable, to prevent occurrence of a blocked state. Alternatively the entity may signal that the controllable valve must be closed immediately.
The error signal indicative for a detection of a too low gas pressure before a predetermined time interval will in practice occur if the controllable valve is already in a closed state. Nevertheless as will be apparent in the sequel, an error signal (e.g. from another safety facility) may be issued also in an opened state of the controllable gas valve. Accordingly, blocking the controllable valve in a closed state is understood to mean that the controllable valve when already in a closed state is maintained in said closed state and the controllable valve when not yet in the closed state is set into the closed state and maintained in the closed state.
The gas delivery control system according to the present invention may be expanded with additional security facilities for delivering one or more detection signals. In the expanded version of the gas delivery control system the blocking means also block the controllable valve in a closed state upon delivery of at least one of said one or more detection signals. Example of such additional security facilities are a smoke signaling device for delivering a smoke detection signal upon detection of smoke, a fire signaling device for delivering a fire detection signal upon detection of fire, a gas signaling device for delivering a gas detection signal upon detection of gas, and a mains voltage detector for delivering a mains failure signal upon detection of a failure of the mains. Alternatively the gas delivery system may be arranged as a fail-safe system in that it keeps the controllable gas valve in a closed state if a mains voltage is absent, for example by mechanical means, such as a spring, or by using gravity. The gas signaling device may be a device for signaling gas delivered by the gas delivery control system, but alternatively or in addition a gas signaling device may be present that detects gasses resulting from combustion of the delivered gas, for example a CO-detector.
In an embodiment of the gas delivery control system the control device has a rest state, an operational state and a safety state, in which rest state the controllable gas valve is maintained in a closed state, in which operational state the controllable gas valve is maintained in an opened state and in which safety state the controllable gas valve is maintained in a closed state, wherein a transition takes place from the rest state to the operational state upon a gas request of a facility, wherein a transition takes place from the operational state to the rest state upon absence of a gas request from a facility, wherein a transition takes place to the safety state in case the error signal is issued, and wherein a transition takes place from the safety state to the rest state in case of a reset signal.
In a particular version of this embodiment the control device further has an initial state wherein the controllable gas valve is maintained in a closed state and wherein the control device maintains the initial state as long as the gas pressure delivered by the gas supply is outside predetermined bounds and the control device assumes the rest state when the supplied gas pressure assumes a value within the predetermined bounds. In this way also protection is offered against hazards associated with a malfunction of the appliances coupled to the gas delivery control system that would be caused by operation at an unsuitable gas pressure.
The apparatus may have additional gas pressure sensors to sense an out of bound value, e.g. an over pressure and/or an under pressure. Alternatively the gas pressure sensor for determining whether the gas pressure in the conduit has a value lower than a pressure reference value also forms the sensor for detecting an under-pressure condition and/or the sensor for detecting an over-pressure condition. When measuring a pressure it may be taken into account that the gas pressure responds with delay to events occurring remote in the conduit. For example the switching of a gas valve stream-downward in the conduit will induce a pressure wave in the conduit that arrives with delay at a position near the controllable gas valve. Likewise, the act of opening the controllable gas valve will result with delay in a pressure increase stream-downward in the conduit. In practice this will generally have no consequences for the determination whether the gas pressure in the conduit has a value lower than the pressure reference value, as this determination always takes place after a predetermined time interval has lapsed since a closure of the controllable gas valve. Temporary pressure fluctuations due to sudden changes in the gas flow in the conduit may be dampened by dampening means, such as reservoirs and additional valves, e.g. bypass valves that allow for a gradual transition of the gas flow. Also electronic means may be applied for damping fluctuations in the gas flow. Alternatively or additionally the controllable gas valve may be arranged to gradually change its state from a fully closed state to a fully opened state or vice-versa.
Various ways may be conceived to inform those involved of hazardous situations. For example the arrangement according to the first aspect of the invention may comprise a communication facility that includes a notification selection facility, for selectively notifying an error- or detection signal to one or more addressees. In this way the communication facility may optimally inform those involved of hazardous situations caused by a gasleak, when an error signal is issued by the error signaling module. Such a communication facility can also be used to communicate a detection signal that indicates smoke, fire, a gas leak or a mains failure, but also an error detected upon a self test, a maintenance signal indicative for a require maintenance. Also the communicated signal may be a logical combination of error or detection signals.
In a practical embodiment of this arrangement the one or more addressees are selected from an addressee database. The addressee database may further comprise indications for a relation of the addressee to the gas delivery control system. Possible relations are for example, the addressee is an inhabitant of the premises where the gas delivery control system is installed. The addressee is a nearest relative of such an inhabitant. The addressee is (voluntary) assistant, living near said premises and having the required capabilities to intervene dependent on the type of error signaled. The addressee is the nearest fire brigade etc.
The communication facility may be provided with a user interface, allowing the user to set-up and modify the selection criteria. I.e. the user may specify actions to be performed automatically. The user may also specify who is to be informed depending of the type of alarm.
In the arrangement according to the present invention a detection of a gasleak will automatically cause a closure of the main gas valve/tap in order to avoid hazardous situations. The user may have the option to determine via the user interface whether it is necessary to automatically inform the addressees. The user may for example select a limited number of addressees to inform, for example the main inhabitant or caretaker of the residence where the gas delivery control system is installed, and possibly the contactor responsible for maintenance and repair of the arrangement. It may also be communicated that gas delivery is already blocked. After a remote reset of the blocked condition with a special app (application) (e.g. a software functionality available on a smart phone or computer device) by the main inhabitant, caretaker or contractor, the consequent situation can be rapidly handled by the persons involved. Possible service or maintenance can be provided then. The particular app (application) may provide for predetermined menus according to a protocol that allows to specify the required steps to be taken. The availability of the protocol improves safety, in particular in unexpected situations, where the persons concerned would otherwise not have the proper data available necessary to correctly handle the situation.
By way of example a hazardous situation may be signaled by a detection signal indicate fire or smoke detected by a fire or smoke detector. In that case a special app (application) activated upon receipt of the detection signal may initiate the following protocol. First, by means of the gasdelivery control system gas delivery is automatically blocked. Simultaneously all involved persons are informed by a message sent to their telephone or other communication device. Upon receipt of this message the communication device generates a clearly visual and/or auditive and/or sensible alarmsignal possibly using the specially designed app (application). Also other coupled systems and device may receive a message indicative for the hazardous situation. Upon receipt of the message a phone or other mobile communication device may be activated to automatically serve as a light source.
The communication devices activated by the message may be automatically set to a mutually coupled mode, therewith allowing communication between the involved persons via the mutually coupled communication devices. Therewith panic can be prevented. This mutually coupled mode also allows the persons involved to coordinate their actions. To that end the communication devices may be specially developed for this purpose or the communication devices may be a general purpose communication having installed thereon a suitable software application. The persons involved may thereby be guided according to a protocol that is activated by the app (application) upon receipt of the message.
A message may also be communicated to the fire brigade. However, the protocol that guides the persons involved in handling the hazardous situation may avoid unnecessary turn out of the fire brigade.
If the hazardous situation however appears to be a serious fire, then the app (application) may assist to clearly visualize the situation. For example the app (application) may indicate the location of persons in the premises that is in fire, the exact location of the fire. The app (application) may indicate whether the persons involved have already given their response. This allows a safer and more efficient handling of rescue operations.
The app (application) may further allow transmission of images of the situation to emergency services, so that they are early informed of the local situation. At the same time the emergency services may be informed that gas delivery is blocked by the gas delivery control system
However, in case a hazardous situation, e.g. a fire, is actually detected the communication system will typically automatically communicate the detected hazard, irrespective the preferences of the user.
In an embodiment said notification selection facility may select one or more addressees that are closest to a location controlled by the gas delivery control system. To that end the addressees may be equipped with a (GPS) location identification facility, or other facility that reports their availability to the communication facility. In an embodiment the notification selection always notify certain parties irrespective whether their availability. For example in an embodiment the main inhabitant is always notified.
Any medium and or communication device may be used to address the addressee. For example, the one or more addressees are addressed via mail, sms, twitter, amber alert, via a social medium, such as facebook, hyves, twitter, skype or via any other communication mode. Communication devices where the addressee may receive the message are for example a (smart) phone, a notebook, an iPad, or any other device. Preferably the addressees are addressed via a combination of available media, so that the probability of reaching the one or more addressees are maximized.
Further safety measures are possible. For example, the arrangement may further comprise an emergency illumination system, arranged for switching on illumination upon activation of an error- or detection signal. This enables inhabitants to quickly remove the building struck by an emergency such as a fire and aids emergency assistants in rapidly finding their way to the location of the emergency, so that they can efficiently take the necessary actions. The emergency illumination system may reuse normal illumination facilities present in the building, but may alternatively use separate illumination facilities that are powered autonomously, so that they also function in case of a mains power failure.
These and other aspects are described in more detail with reference to the drawings. Therein:
In the following detailed description numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by one skilled in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, software, apps and components have not been described in detail so as not to obscure aspects of the present invention.
It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, software, apps and/or sections, these elements, components, software, apps and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, or section from another or section. Thus, a first element, component, software, app or section discussed below could be termed a second element, component, or section without departing from the teachings of the present invention.
Embodiments of the invention are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
In many cases gas installations the facility to be coupled has a single gas appliance which requests gas for restricted time periods. By way of example a central heating facility in a typical home application may use about 3.2 m3/hour during a heating phase, whereas its expected annual use is about 1600 m3. Accordingly the exemplary gas appliance only is actually operative during approximately 6% of the time. Accordingly, even if no error is detected the gas delivery control system will in practice close the controllable gas valve during most (94%) of the time and therewith contribute to safety. The facility to be coupled may include additional gas-appliances. In that case the gas request signal is generated if at least one of the gas-appliances included in the facility requests gas. In such an application comprising a plurality of gas-appliances the controllable gas valve may in practice be in an opened state for a larger time-fraction, e.g. for 20, 50 or 95% depending on the number of appliances and a period of the year. However, the conditional opening of the controllable gas valve will anyhow result in an increase safety. Moreover, upon detection of an error the user, or the system automatically closes the controllable gas valve permanently until it is reset and therewith centrally blocks leakages that could occur due to defect appliances and due to cracks and damages in the gas distribution system for example caused by subsidences and collapses.
The controllable gas valve is preferably arranged at a location close to the entrance of the gas supply in the premises for which gas delivery is controlled or even at a location more stream upwards. In this way a closure of the controllable gas valve most effectively protects against leakages. The controllable gas valve is preferably arranged at a location where it is protected against fire and other hazards.
In an embodiment the appliances AP coupled to the gas delivery control system 1 are provided with internal control means to inhibit the request signal S1 if an internal error has been detected. Many appliances are already provided with a self test. An error condition from this self test may be used to inhibit the request signal S1.
The gas delivery control system has a gas pressure sensor 40 for determining whether the gas pressure in the conduit 22 has a value lower than a pressure reference value Pref. The gas delivery control system further has a reference module 50 for determining whether a predetermined time interval has lapsed since the last time that the controllable gas valve was closed. The gas delivery control system further has an error signaling module 60 for issuing an error signal Error if it is detected before a lapse of the predetermined time interval that the gas pressure is lower than the pressure reference value.
In the embodiment shown the gas delivery control system is coupled to an alarm centre AC to enable transmission of the error signal Error. The coupling further enables a transmission of a block signal Block from the alarm centre to the control device 30 to enable a remote blocking of the gas supply. The block signal may be issued automatically or may be provided manually by an employee of the alarm centre. After it is determined that the situation is safe a reset signal Reset is generated by a reset facility, such as button RST. The step of resetting may a final step of a protocol according to which various conditions are checked.
In an embodiment, the gas request signal may indicate a requested gas flow level. In that embodiment the control device may allow the controllable valve to provide a gas flow according to a gas flow level that does not differ more than a predetermined amount (e.g. in time and volume) from the requested gas flow level. The error signaling module therein is arranged to issue an error signal if the difference is larger than the predetermined amount and is further arranged to activate the blocking means to block the valve in a closed state.
In the embodiment described above it is presumed that the appliance AP itself is provided with a facility, e.g. a controller, for generating the gas request signal. The gas request signal generated by the controller is for example a signal that controls an internal gas valve of the appliance.
In an embodiment the appliance AP may be directly coupled to the controllable gas valve 10. In other words the appliance AP may straightforwardly control the controllable gas valve 10 with its gas request signal S1. The gas request signal may be transmitted by a hard-wired connection. In an embodiment the conduit itself may be used in this connection. In an embodiment the gas delivery system has a second controllable gas valve, in series with the controllable gas valve 10 that is controlled by the control device 30. Accordingly gas delivery to the conduit 22 can be shut off by the controllable gas valve 10 is a gas request signal S1 is absent and by the second controllable gas valve if a block signal is generated.
In case the appliance is not (yet) provided with such a facility for generating a gas request signal, such a facility may be provided externally in the form of a gas usage sensor. Preferably the gas usage sensor coupled to the conduit to the appliance. The gas usage sensor detects a usage of the remaining gas in the conduit when the appliance AP starts to consume gas. The gas usage sensor may be a gas flow sensor 40a, that detects a gas flow to the device, or may be a gas pressure sensor 40b that detects the gas-pressure drop due to a gas flow to the device AP. This optional measure provides for a smooth transition towards a final implementation, wherein gas appliances are provided with a module for generating the gas request signal. If required, such an appliance may be provided with an additional gas valve that may also be controlled in accordance with the gas request signal.
As another example of such an optional measure for enabling a smooth transition a pressure sensor 40b is used as the facility for generating the gas request signal S1. This sensor 40b typically has a detection level lower than the detection level of the gas pressure sensor 40. By way of example the normal operation pressure may have a value in the range of 20 to 50 mbar, the gas pressure sensor 40 may have a detection level in the range of 0.7 to 0.8 times the normal operation pressure and the sensor 40b may have a detection level in the range of 0.60 to 0.65 times the normal operation pressure. For example the gas pressure sensor 40 may have a detection level of 0.75 times the normal operation pressure and the detector 40b may have a detection level in the range of 0.62 times the normal operation pressure. For example the normal operation pressure may be 40 mbar, the gas pressure sensor 40 may have a detection level of 30 mbar and the sensor 40b may have a detection level of 25 mbar.
In an embodiment the sensor 40 responds with a hysteresis of time QT. I.e. only if a pressure below the detection level of this sensor occurs during a time interval longer than QT, the sensor 40 issues an under-pressure signal.
In an embodiment the sensor 40b has a delay of duration X. I.e. the sensor 40b will immediately generate the gas request signal S1 when a pressure below its detection level is detected, and the sensor 40b will continue generating the gas request signal S1 until a time period X after the moment that the pressure has decreased below the detection level. In case a gas appliance is switched on, the gas pressure in the conduit will rapidly descend. Accordingly, in that case, before the time period QT is lapsed, the gas pressure will have further descended to the detection level of the sensor 40. At the moment the detection level of the sensor 40b is reached the latter generates the gas request signal, so that the controllable gas valve 10 is opened and the gas pressure in the conduit increases rapidly to the normal operation pressure, above the detection level of the pressure sensor 40. Therewith the time interval that the gas-pressure is below the detection level of sensor 40 is too short for this sensor to respond. However, in case of a gas leak, the gas pressure typically drops slowly in after the controllable gas valve 10 is shut. Therewith a relatively long time interval passes between the moment that the detection level of the sensor 40 is reached to the moment that the lower detection level of the sensor 40b is reached. In this case the time interval that the gas-pressure is below the detection level of sensor 40 is longer than the hysteresis time interval of sensor 40 so that it generates an error signal and the controllable gas valve 10 is closed.
The sensor 40 and 40b may be formed by a single measuring device that is capable of detecting the upper and the lower detection level, and that has a hysteresis circuitry for generating the signal indicative for a pressure below the upper detection level with a hysteresis QT.
In case the sensors 40 and 40b are not formed by a single measuring device, the signals obtained from pressure sensor 40 and sensor 40b may further be compared to determine if an abnormal pressure difference is measured. A substantial lower pressure measured by sensor 40b that the pressure measured by 40 is an indication for a leak in the conduit 22 and may be used to generate an error signal.
Also the gas pressure at other locations in the gas distribution may be compared to detect anomalies. For example the gas pressures at the input 12 and the output 14 of the controllable gas valve 10 may be compared when the controllable gas valve 10 is open during a period that no gas request signal is raised. Normally the difference between these gas pressures is at least substantially equal to zero. In case a leak is present in the gas distribution system, the pressure difference will be higher than a predetermined reference value. Upon detection thereof an error signal is raised.
A flow sensor 40a can also be used to determine whether the gas consumption by the appliance AP is within normal bounds. The measured gas flow may for example be compared with a minimum and/or a maximum flow. If the measured gas flow is outside these bounds an error signal FE1 is generated. This error signal can be used to alert an alarm centre that an anomalous situation is present or can be used to directly activate the blocking means 30.
In
In an embodiment the pressure sensor 40 is used to generate the gas request signal. In said embodiment an output signal Plow of the gas pressure sensor 40 indicative for a gas pressure lower than a minimum value is also used as an indication that gas is requested by the appliance, i.e. as a gas request signal S1. During normal operation it is expected that the signal Plow is repeated after a predetermined reference time interval, for example Tref, which is dependent on an expected use of the appliance AP. However, if a leak occurs the signal Plow will be repeated before the end of said predetermined time interval. Upon detection of this condition an error signal is generated.
Various alternatives are possible to carry out embodiments of the present invention. By way of example one embodiment is worked out in more detail. Due to the fact that it is sufficient to determine whether the gas pressure is below a pressure reference value the unit 40 for asserting this condition can be simple and reliable. For example a membrane sensor 40 may be used as shown in
Nevertheless it would still be possible to use a full fledged manometer 44 instead as indicated in
whether a signal indicative for the measured pressure Sp exceeds a reference value Ref.
It is also noted that the system need not necessarily be implemented by electronic components. For example a mechanic, a pneumatic or hydraulic implementation or a hybrid implementation using various technologies may be considered. In view of the fact that the number of logic functions may be relatively modest, the logical functions could for example be implemented by electro-mechanical components, such as a relay.
In an embodiment the system of
As is schematically shown in
In a particular embodiment the gas request signal S1 may be transmitted to the controller 30 via a hardwired signal connection. In a particular implementation thereof, the additional security facilities control interrupt contacts that interrupt this hardwired signal connection. Hence, in case one or more of these additional security facilities generate a detection signal, the controllable gas valve 10 is maintained in a closed state even if a gas request is indicated by the gas request signal.
In an embodiment the gas delivery control system has a sensor arranged stream downwards with respect to the controllable gas valve that detects whether an under-pressure condition occurs in the conduit during an opened state of the controllable gas valve. The gas delivery control system is arranged to generate an error signal if the under-pressure condition is detected. A too low gas pressure in an opened state of the controllable gas valve may be indicative of a leak in the conduit stream upwards or stream downwards the controllable gas valve. In any case a too low operational pressure may lead to a hazardous situation due to an unreliable combustion of gas in the appliance coupled to the conduit. In particular this may result in a flow of uncombusted gas out of the appliance. An under-pressure condition may also occur for example during maintenance by the gas provider. Accordingly, the presence of a sensor that detects whether the gas pressure in the conduit has a value below an operational minimum level in an opened state of the controllable gas valve provides an additional safety measure against this hazardous situation and against hazards due to a sudden rupture of a conduit as it enables an immediate closure of the controllable gas valve. In this way the gas-delivery system according to the present invention additionally provides the function of a gas lack valve, also denoted as B-valve. The sensor for this purpose may be identical to the gas pressure sensor for determining whether the gas pressure in the conduit has a value lower than a pressure reference value.
In an embodiment the gas delivery control system has a sensor arranged stream downwards with respect to the controllable gas valve that detects whether an over-pressure condition occurs in the conduit during an opened state of the controllable gas valve. The gas delivery control system is arranged to generate an error signal if the over-pressure condition is detected. A too high operational pressure also may lead to a hazardous situation due to an unreliable combustion of gas in the appliance coupled to the conduit. An over-pressure sensor provides a safety measure to prevent this situation. In an embodiment both an under-pressure and an over-pressure sensor may be present.
One sensor may both function as the over-pressure sensor and the under-pressure sensor. E.g. a sensor may be used that issues an electronic signal representative for the measured pressure and that has a first and a second threshold detector that indicate whether the electronic signal is indicative for an over-pressure condition, an under-pressure condition, or a normal pressure.
In practice temporary perturbations of the gas-pressure in the gas distribution net may occur, for example during maintenance of the gas distribution net or during an extremely high gas consumption by an other user coupled to the gas distribution net. The gas distribution net is understood to be the provider of the gas to the gas delivery system, for example a public gas distribution net. Such temporary perturbations are not dangerous as long as no appliance coupled to the gas delivery system is activated. If desired, all measurements by a sensor or other measurement means may be carried out more than once, and the resulting measurements may be averaged, to obtain an temporal average measurement value.
An embodiment wherein the over-pressure sensor and/or the under-pressure sensor are arranged stream downwards the controllable gas valve and therewith only responds during an opened state of the controllable gas valve has the advantage that such temporary pressure perturbations do not result in an error condition, provided that gas requests are absent and the controllable gas valve is closed.
It is another advantage of this embodiment that the gas pressure sensor for determining whether the gas pressure in the conduit has a value lower than a pressure reference value may also serve as the sensor for detecting an under-pressure condition and/or the sensor for detecting an over-pressure condition. In this way the total number of components can be modest, while still additional protection against extreme pressure fluctuations during an activated state of the appliances is provided. The latter combined gas pressure sensor may for example have different detection levels, including an operational minimum level, an operational maximum level and a non-operational minimum level.
Nevertheless an embodiment is possible wherein the gas delivery control system alternatively or in addition has a sensor arranged stream upwards with respect to the controllable gas valve 10 that detects whether an under-pressure condition occurs in the conduit, said gas delivery control system being arranged to generate an error signal if said under-pressure condition is detected. Such an under pressure sensor will always respond irrespective whether the controllable gas valve is opened or closed.
Also an embodiment is possible wherein the gas delivery control system alternatively or in addition has a sensor arranged stream upwards with respect to the controllable gas valve 10 that detects whether an over-pressure condition occurs in the conduit, said gas delivery control system being arranged to generate an error signal if said under-pressure condition is detected. Such an over pressure sensor will always respond irrespective whether the controllable gas valve is opened or closed.
The under pressure sensor and the over pressure sensor may be formed by a combined gas pressure sensor that has different detection levels, including an operational minimum level and an operational maximum level.
In
It is an advantageous aspect of the gas delivery control system according to the present invention that the higher the leakage, the more rapidly this will cause the pressure P to drop and the more rapidly the condition occurs that the pressure is below the lower threshold value Pt. Accordingly the present gas delivery control system provides a rapid detection in case of serious leaks
S1) of a gas request S1 from the facility AP. A transition takes place to the safety state ST4 in case the error signal Error is issued. In the embodiments described above, the error signal is issued when the control device 30 has assumed the rest state ST2 and the gas pressure drops rapidly after switching of the controllable gas valve 10. However additional conditions may be verified that result in the generation of an error signal when the system is in another state, for example in the operational state ST3. Also in that case a transition takes place to the safety state. Once the gas delivery control system is checked and repaired a reset signal can be provided by an authorized technician for causing a transition from the safety state to the rest state so that normally operation can be resumed.
The control device in the gas delivery control system of
In the embodiment of
The gas supply GS is coupled to the gas delivery control system via a main valve/tap MV and a pressure regulator PR. The latter serves to regulate the pressure within acceptable bounds for normal operation of the appliances provided by the system. In an embodiment the functionality of the main valve/tap MV may be integrated in the controllable gas valve 10. Authorized entities, for example, the fire department may be authorized to close the controllable gas valve 10 remotely in case of a fire hazard. Also the controllable gas valve may be integrated in another device, e.g. a smart gas meter or a gas payment terminal. A gasmeter GM is arranged to measure the gas consumption. Gas consumption may be measured by mechanical means, for example by counting a number of times a bellows is filled, but alternatively by contactless sensing, e.g. using an UV-measurement. Various other gas measuring systems can be used like digital (volume) meters, mass meters, rotor meters, Doppler meters, displacement meters, electromagnetic flow meters, vortex shedding or Corolis massflow meters. These meters may be temperature compensated. In embodiments the gas consumption may be measured indirectly, e.g. with a calorimeter that measures an amount of heat generated by devices supplied by the gas delivery system. In another embodiment gas may be delivered for a fixed price, so that a measurement of gas-consumption is superfluous. In the present embodiment the gasmeter GM is coupled with an energy meter EM for measuring the electric power consumption.
Downstream the system appliances are arranged, such as a central heating installation AP and other appliances OAP.
The gas delivery control system 1 has apart from the components earlier mentioned a power supply PO. Various alternatives are suitable, comprising a mains power supply in particular wherein the gas delivery system is integrated with components of a mains power supply system, e.g. the energy meter in this case. Alternatively other energy sources may be used, such as batteries or solar cells. It may also be consider to use the gasflow itself as a source of energy. Various communication facilities COM1, COM2, COM3 are provided to couple the gas delivery control system 1 with other facilities. In this case a first communication system COM1 provides for communication between the components of the gas delivery control system, e.g. the controllable gas valve 10, the control device, the gas pressure sensor 40, and the reference module 50. The first communication system COM1 may further provided for communication with external facilities coupled to the system 1, such as the pressure regulator PR, the gas meter GM, the energy meter EM and external safety facilities, such as a fire detector FD. A second communication system COM2 provides for communication with the facility AP to be provided with gas by the gas delivery control system 1. In this way the facility AP can for example provide the request signal S1 to indicate that gas is requested. In practice more facilities OAP may be coupled to the gas delivery control system 1. For that purpose one or more additional communication systems COM3 may be present, for example to receive a request signal indicative for a demand of gas. Typically the communication systems are wired or wireless electronic systems. For that purpose also existing communication means may be used, such as public phone net, a glass fiber net and or/an internal home bus, e.g. according to one of the BCI, the EHSA or the EIBA standard. Nevertheless signals could also be transmitted by other means, e.g. by electrical, mechanical, pneumatical or hydraulical communication means. Facilities already present may be reused for this purpose, e.g. the gas-conduit may be used as an electrical conductor for transmitting signals.
To support wireless communication RF communication means may be provided that enable communication with an app, installed on a remote device, for example a mobile remote device, such as a (smart) telephone.
In case more than one facility AP, OAP is coupled to the system the request signal S1 is replaced by a combined request signal S1′ that indicates whether at least one of the facilities requests a gas supply.
One or more components of the gas delivery control system 1 may be integrated, for example with or within other components, for example a gas meter, for example with a so called “smart energy meter”. A smart gas meter may be provided with communication facilities with the energy provider. Such a smart energy meter may for example enable the provider to read out energy use remotely and/or to locally control gas supply. Local control of gas supply may take place via the controllable gas valve 10 of the gas delivery control system 1.
A smart gas meter may include one or more of an under/overpressure switch, to detect an out of boundary condition of the gas pressure and to shut of gas-delivery upon detection of the condition.
The smart gas meter may further provide the pressure sensor for use in the gas delivery control system. The gas delivery control system may be integrated within a housing of the smart gas meter. The smart gas meter may additionally be provided with power supply means for the gas delivery control system 1. The smart gas meter is for example a smart energy meter that not only serves for measuring a gas use, but additionally measures use of electricity. In that embodiment the smart energy meter is inherently coupled to the mains, which may also form the power supply for the gas delivery control system. The smart gas meter may have a gas flow sensor which is also used by the gas delivery control system.
The gas delivery control system 1 as shown comprises a display DP for displaying a status of the gas delivery control system 1 and possibly also of facilities coupled thereto. A control panel may be provided to change settings of the gas delivery control system 1. The control panel may for example comprise a reset button RS to reset the system after an error condition was signalled and repair has taken place. In an embodiment an authorization is required to reset the system 1, so that gas delivery cannot be erroneously resumed before the cause of the error condition is cancelled. The control panel may further be provided with a facility to enable the system 1 during first use. In this situation a false error could be generated due to the fact that the gas pressure in the system is not yet at its normal level. A button may be provided to temporarily overrule the blocking facility 31 incorporated in the control device 30,
A smart gas meter SGM may have a gas flow sensor 40a and a controllable valve 10. The smart gas meter SGM further has communication and control facility COMM & CNTRL, coupled to a power source PWR, e.g. a mains supply and a communication net COMM NET that enables a gas provider GP to remotely read the use of the gas consumption and to remotely control the controllable gas valve 10. In a further embodiment the gas pressure sensor 40 is also integrated in the smart gas meter SGM. In the embodiment shown the controllable gas valve 10 of the smart gas meter SGM also serves as the controllable gas valve 10 of the gas delivery control system. This controllable valve may also be arranged stream upwards with respect to the smart gasmeter, so that also eventual leakages in the smart gasmeter may be interrupted by closure of controllable valve. The gas delivery control system uses the communication net COMM NET to communicate the error signal Error/block as well as the gas request signal S1 to the control facility of the smart gas meter SGM. The communication net COMM NET may be any wired or wireless communication system. The power source available for the smart gas meter SGM may also be reused as the power source for the gas delivery control system. In a particular embodiment the reference module 50 and the error signaling module 60 may be fully integrated in the smart gas meter SGM. The communication and control facility of the smart gas meter may be a programmable controller or other and the functions of these modules 50, 60 can be implemented by a reprogramming of the controller COMM & CNTRL. Alternatively part or all functions may be implemented in dedicated hardware. It is not necessary that the controller of the smart gasmeter is physically present in its housing. The controller of the smart gas meter may for example be a common control facility of the gas supplier that remotely controls the operation of the smart gas meter. Other functionalities may be provided in the gas delivery system, such as visual and auditive display means. Reset and other control facilities may also be included.
It is not necessary that only a single gas delivery control system is integrated with a smart gas meter, in an embodiment the gas delivery control system is part of a plurality of gas delivery control systems that are integrated with/in the gas meter. Therein each gas delivery control systems is arranged to supply gas to a proper appliance or set of appliances. Therewith the appliances may be separately controlled.
The gas delivery control facility 1 may have other features in accordance with prevailing safety and installation regulations and recommendations.
Summarizing, a gas delivery control system is disclosed comprising a controllable gas valve. The controllable gas valve has an input to be coupled to a gas supply and having an output that is coupled via a conduit to a facility. A control device is provided that controls the controllable gas valve in accordance with a value of a request signal of the facility. An error signaling module issues an error signal if it is detected before a lapse of the predetermined time interval that the gas pressure is lower than the pressure reference value.
The installation costs of the gas delivery control system may be further reduced by combining functions with those of other provisions, such as (smart) gas/energy meters, gas using appliances, computers, alarm installations and available communication means. For example the controllable gas valve may also be the main gas valve/tap. Electronics present in various devices provided with, arranged with or coupled to the gas distribution system may be used. For example a central heating system may already issue a control signal for opening an internal valve inside. This control signal can be used as the gas request signal. As an alternative, a pressure detection device may be arranged in the conduit, preferably close to the appliance that detects a lowering of the pressure in the conduit when an internal valve of the appliance is opened and in response generates a gas request signal.
In embodiments a gas buffering container may be coupled to the conduit 22.
In an embodiment the gas delivery control system includes a gas flow sensor that generates an error signal upon detection of abnormalities in a gas flow. In an embodiment the gas flow sensor is part of a (smart) gas usage meter. The results of the gas flow measurements may be compared with an expected flow that is estimated on the basis of the detected on-time of the attached gas-appliances. Also the measurement results may be compared with reference data. An error signal is generated in case of a significant deviation detected during the comparison.
The gas delivery control system provides for a reliable detection against small leaks and a rapid detection against larger leaks. The system is simple in use and can be extended easily. As a further extension for example the system may be amended to interrupt gas-delivery by fail safe facilities, also in the following situations.
The gas delivery control system and or any additional security facilities may include an auto-diagnostic module for internally testing the gas delivery control system and the additional security facilities. The auto-diagnostic module may automatically be activated periodically or at power-up.
In addition or alternatively a facility may be included to activate the auto-diagnostic module manually. Also an auto-diagnostic test may be included after each gas request signal and before gas is supplied in response to the gas request signal.
Upon detection of an error during a test carried out by the auto-diagnostic module, the latter may cause the blocking means to block the controllable gas valve in a closed state.
The gas delivery system may be coupled to other alert or control systems.
Any error signal may communicated to one or more of a user, an inhabitant, a caretaker, the fire brigade, an alarm centre or any other entity that may have an interest to receive this information.
Provided that the prevailing installation regulations allow this, the function of the main gas valve/tap, as shown in
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006387 | Mar 2011 | NL | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/NL12/50100 | 2/21/2012 | WO | 00 | 11/18/2013 |
