Patent Description:
There are many different types of optical flame detectors that can be arranged to detect the presence of flames in an area to be surveilled within the field-of-view of the flame detector. Common varieties are e.g. ultraviolet flame detectors, such as Omniguard® model <NUM>, infrared flame detectors, such as Omniguard® model <NUM>, and ultraviolet-infrared flame detectors, such as Omniguard® model <NUM>. Ultraviolet flame detectors detect ultraviolet radiation from the surveilled area, infrared flame detectors detect infrared radiation from the surveilled area, and ultraviolet-infrared flame detectors detect both types of radiation from the surveilled area.

An optical flame detector may typically be mounted with its field-of-view covering an area where there is a fire hazard, such as e.g. a turbine enclosure, a generator room, a munitions facility, a battery room, a gas cabinet, an aircraft hangar, a fuel transfer station, a hydrogen storage and filling facility, a compressor station, a silane storage bunker, or a paint spray booth. Optical flame detectors may be capable of detecting both hydrocarbon (e.g. gasoline, propane, methane, alcohol) and non-hydrocarbon (e.g. hydrogen, silane, hydrazine, magnesium) flames. However, once an optical flame detector has been arranged with its field-of-view covering an area where there is a fire hazard, there is no way of knowing that the surveilled area stays within the field-of-view of the optical flame detector. This may mean that the optical flame detector cannot be relied upon to safely monitor an area to be surveilled for the presence of flames.

<CIT> describes a self-protected fire-sensing system that includes a tamper sensor for detecting movement to the system.

<CIT> describes an optical flame detector comprising a magnetometer, an accelerometer, and a gyroscope, in a system which also comprises an information handling system configured to obtain orientation data from the magnetometer, the accelerometer, and the gyroscope.

In the system described in <CIT>, the tamper sensor simply determines whether there is movement. There is no processing of the signals from the tamper sensor in any processing device, in order to determine whether the detected movement is abnormal. This means that the tamper sensor will detect tampering as soon as there is any kind of movement to the system.

In the system described in <CIT>, there is no local processing in the optical flame detector. This means that the optical flame detector must have a continuous connection with the information handling system, so that all signals from the magnetometer, the accelerometer, and the gyroscope can be processed there. This also means that it is not possible to integrate any functionalities that need to function without such a continuous connection locally in the optical flame detector.

There is thus a need for an improved flame detecting arrangement.

The above described problem is addressed by the claimed flame detecting arrangement, which comprises: at least one optical flame detector, arranged with its field-of-view covering a predetermined area; at least one movement sensor, arranged together with the at least one flame detector; at least one processing device, arranged together with the flame detector; and indicating means, arranged with the at least one flame detector and arranged on a housing of the flame detector. The at least one processing device is arranged to: receive signals from the movement sensor; detect abnormal movement of the flame detector based on these signals; alert an operator and/or a control system if abnormal movement of the flame detector has been detected; and indicate, using the indicating means, how the at least one flame detector should be oriented in order for its field-of-view to cover the predetermined area. An alert is displayed using the indicating means on the flame detecting arrangement. Such a flame detecting arrangement may ensure that an operator/control system is informed if there is a risk that the field-of-view of the flame detector to no longer cover the predetermined area to be surveilled. This enables the field-of-view of the flame detector to be corrected to the desired, preferably the original, field-of-view The indicating means may preferably be used as an aid during installation of the flame detector.

The above described problem is further addressed by the claimed method for an optical flame detector arranged with its field-of-view covering a predetermined area. The method comprises: receiving signals from a movement sensor arranged together with the flame detector in a processing device arranged together with the flame detector; detecting abnormal movement of the flame detector based on these signals; alerting an operator and/or a control system if abnormal movement of the flame detector has been detected; indicating, using indicating means arranged on a housing of the flame detector together with the at least one flame detector, how the at least one flame detector should be oriented in order for its field-of-view to cover the predetermined area; and displaying an alert using the indicating means on the flame detecting arrangement. Such a method may ensure that an operator/control system is informed if there is a risk that the field-of-view of the flame detector no longer covers the predetermined area to be surveilled. This enables the field-of-view of the flame detector to be corrected to the desired, preferably the original, field-of-view.

The at least one movement sensor is preferably arranged together with the at least one flame detector, so that it senses the same movement as the at least one flame detector. The at least one movement sensor may e.g. be arranged within, or mounted onto, the same housing as the at least one flame detector.

The at least one processing device is preferably a local processing device arranged together with the flame detector. Such a local processing device may e.g. be arranged within, or mounted onto, the same housing as the flame detector. If such a local processing device is used, the signals from the at least one movement sensor may be processed locally, so that there is no need to send any signals to any remote processing device unless abnormal movement is detected. This enables the flame detecting arrangement to function as a stand-alone device, without any connection to any external system. However, the at least one processing device may also be a combination of both a local processing device and a remote processing device, e.g. in a control system.

In embodiments, the at least one movement sensor comprises a vibration sensor. Abnormal movement of the flame detector may be detected based on signals received from this vibration sensor. This allows for detecting any kind of abnormal movement of the flame detector, even e.g. a mild push or shake, that may have caused the field-of-view of the flame detector to no longer cover the predetermined area.

In embodiments, an operator and/or a control system is alerted if abnormal movement in the form of vibrations beyond a predetermined threshold are detected. Even if it is determined that the field-of-view of the flame detector still covers the predetermined area, it may be desirable to alert an operator and/or a control system to the detection of vibrations beyond a predetermined threshold, since vibrations may cause the flame detector to malfunction in other ways.

In embodiments, the indicating means is a laser aiming device, that e.g. aims at the center of the field-of view of the flame detector. Such indicating means may e.g. be a number of LEDs and/or one or more arrows that indicate directions in which the flame detector should be turned in order to cover the desired field-of view. The indicating means may also be a combination of a laser aiming device and LEDs and/or arrows. In embodiments, it is determined whether the field-of-view of the flame detector still covers the predetermined area. This determination may e.g. compare the signals received from the at least one movement sensor with stored orientation data representing the orientation of the at least one flame detector when it is arranged so that its field-of-view covers the predetermined area. This is a simple way of determining whether the field-of-view of the flame detector still covers the predetermined area.

In embodiments, the at least one movement sensor comprises at least one of an accelerometer, a gyroscope, an inertial measurement unit, and/or a direction sensing device, such as a compass. Based on the signals from at least one of these sensors, it may be determined whether the field-of-view of the flame detector still covers the predetermined area.

In embodiments, it is determined whether the field-of-view of the flame detector still covers the predetermined area only after first detecting abnormal movement of the flame detector. This saves on processing resources, since such a determination may be much more complicated than just detecting abnormal movement of the flame detector. Further, if the flame detecting arrangement comprises both a local processing device and a remote processing device in a control system, and the determination of whether the field-of-view of the flame detector still covers the predetermined area is made in the remote control system, it may be an advantage for the local processing device not to have to communicate with this remote control system until abnormal movement of the flame detector has been detected by the local processing device.

In embodiments, it is determined whether the field-of-view of the flame detector still covers the predetermined area using image processing software. Unless the flame detector is image based, this may require the flame detecting arrangement to comprise an image generating device.

That a device is "arranged together with the flame detector" according to this disclosure means that the device experiences the same movements as the flame detector. This may be accomplished by the device being arranged within the same housing as the flame detector, but it may also be accomplished by the device being mounted onto the flame detector housing, or just onto the same structure as the flame detector.

The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly.

When an optical flame detector has been arranged with its field-of-view covering an area where there is a fire hazard, there is no way of knowing that the surveilled area stays within the field-of-view of the flame detector. This may mean that the flame detector cannot be relied upon to safely monitor an area to be surveilled for the presence of flames. It is therefore important that an operator and/or a control system is alerted if abnormal movement of the flame detector has been detected.

The present disclosure relates generally to flame detecting arrangements and methods. Embodiments of the disclosed solution are presented in more detail in connection with the figures.

<FIG> schematically illustrates a flame detecting arrangement <NUM>, in accordance with one or more embodiments described herein. The flame detecting arrangement <NUM> comprises at least one optical flame detector <NUM>, at least one movement sensor <NUM>, and at least one processing device. The at least one processing device may be a local processing device <NUM>, arranged together with the flame detector <NUM>, but it may also be a remote processing device, e.g. in a control system <NUM>, or a combination of both. The at least one movement sensor <NUM> is arranged together with the at least one flame detector <NUM>, so that it senses the same movement as the at least one flame detector <NUM>. The at least one movement sensor <NUM> may e.g. be arranged within, or mounted onto, the same housing as the at least one flame detector <NUM>. The flame detecting arrangement <NUM> also comprises indicating means <NUM>.

During use, the at least one optical flame detector <NUM> is arranged with its field-of-view covering a predetermined area, as shown schematically in <FIG>. The at least one optical flame detector <NUM> may e.g. be fixedly mounted in a position where its field-of-view covers an area where there is a fire hazard, such as e.g. a turbine enclosure, a generator room, a munitions facility, a battery room, a gas cabinet, an aircraft hangar, a fuel transfer station, a hydrogen storage and filling facility, a compressor station, a silane storage bunker, or a paint spray booth.

The at least one processing device <NUM> is arranged to receive signals from the movement sensor <NUM>, and detect abnormal movement of the flame detector <NUM> based on these signals. Abnormal movement of a flame detector <NUM> may e.g. be caused by people or equipment accidentally pushing the flame detector <NUM>. For outdoor mounted flame detectors <NUM>, abnormal movement may also be caused by weather conditions, such as e.g. severe winds, waves, or earthquakes.

Since an optical flame detector <NUM> cannot be relied upon to safely monitor an area to be surveilled for the presence of flames unless its field-of-view covers the area where there is a fire hazard, it is important to inform any person or control system <NUM> relying on the flame detector <NUM> as soon as possible if abnormal movement of the flame detector has been detected. The at least one processing device <NUM> is therefore arranged to alert an operator and/or a control system <NUM> if abnormal movement of the flame detector has been detected, in order to enable correction of the field-of-view of the flame detector to the desired, preferably the original, field-of-view.

The at least one optical flame detector <NUM> may e.g. be an ultraviolet flame detector (such as e.g. Omniguard® model <NUM>), an infrared flame detector (such as e.g. Omniguard® model <NUM>), or an ultraviolet-infrared flame detector (such as e.g. Omniguard® model <NUM>).

At least one processing device is a local processing device <NUM> arranged together with the flame detector <NUM>. This local processing device <NUM> may e.g. be arranged within, or mounted onto, the same housing as the at least one flame detector <NUM>. The signals from the at least one movement sensor <NUM> may be processed locally, so that there is no need to contact any control system <NUM> unless problems are detected. However, if the local processing device <NUM> detects movement of the flame detector <NUM> beyond predetermined thresholds, a control system <NUM> should preferably be contacted. An operator may in that case be alerted through the control system <NUM>, and/or through the local processing device <NUM>, which may e.g. display an alert using the indicating means <NUM> on the flame detecting arrangement <NUM>. In embodiments, signals from the flame detecting arrangement <NUM> may also be sent directly to a user device such as e.g. a mobile phone.

The local processing device <NUM> enables for the flame detecting arrangement <NUM> to be connected to any kind of system, since the signal from the flame detecting arrangement <NUM> in case of a detected abnormal movement in such a case may be very simple. This is advantageous, since there are in many countries standards that must be met for primary security functions such as fire alarm systems. Such standards may e.g. specify that the signal sent from a flame detecting arrangement <NUM> to a fire alarm must follow a certain international standard, such as e.g. being a relay output or a current output (<NUM>-<NUM> mA) from a fire detecting arrangement <NUM>. The local processing device <NUM> may enable for the flame detecting arrangement <NUM> to be arranged to provide any output needed to follow such a standard. The output from the flame detecting arrangement <NUM> could then also easily be received by any kind of control system <NUM>.

The at least one movement sensor <NUM> may comprise a number of different sensors. In the embodiment shown in <FIG>, the at least one movement sensor <NUM> comprises a vibration sensor <NUM>, an accelerometer <NUM>, a gyroscope <NUM>, an inertial measurement unit <NUM>, and a direction sensing device, such as a compass <NUM>. Normally, the at least one movement sensor <NUM> would not comprise all of these sensors, but any combination of one or more sensors is conceivable.

If the at least one movement sensor <NUM> comprises a vibration sensor <NUM>, the at least one processing device <NUM> may be arranged to receive signals from the vibration sensor <NUM>, and detect abnormal movement of the flame detector <NUM> based on these signals. This allows for detecting any kind of abnormal movement of the flame detector <NUM>, even e.g. a mild push or shake, which may have caused the field-of-view of the flame detector to no longer cover the predetermined area. The signals from the vibration sensor <NUM> may e.g. be evaluated over time, in order to e.g. be able to treat continuous movement differently from instantaneous movement. This may be done e.g. by integrating the signals from the vibration sensor <NUM>, and/or determine the average value of the signals from the vibration sensor <NUM>. If the flame detecting arrangement <NUM> is arranged in a non-static environment, such as on e.g. on an oil rig, there may be continuous movements caused by waves that do not affect the position and orientation of the flame detecting arrangement <NUM>. If there are several flame detecting arrangements <NUM> in the same location, e.g. on the same oil rig, signals from the vibration sensors <NUM> of the different flame detecting arrangements <NUM> may be compared with each other in order to detect abnormal movement of one of the flame detectors <NUM>.

The at least one processing device <NUM> may be arranged to alert an operator and/or a control system <NUM> if abnormal movement in the form of vibrations beyond a predetermined threshold are detected, even if it is determined that the field-of-view of the flame detector <NUM> still covers the predetermined area. It may be desirable to alert an operator and/or a control system <NUM> to the detection of vibrations beyond a predetermined threshold, since vibrations may cause the flame detector <NUM> to malfunction. Such a threshold may also be defined as a range within which vibrations are acceptable, especially if the flame detecting arrangement <NUM> is arranged in a non-static environment, such as e.g. on an oil rig. There may be an option to define such a range, e.g. during installation of the flame detector <NUM>, or via a control system <NUM> at a later stage. The range may also be defined by training the system through e.g. recording the vibrations over a certain time span, such as e.g. one hour, <NUM> hours, or a week, and setting the range based on defining all vibrations detected during this time span as normal movement.

The at least one processing device <NUM> is arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area.

If the at least one movement sensor <NUM> comprises an accelerometer <NUM>, the at least one processing device <NUM> may be arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area based at least on signals received from the accelerometer <NUM>. An accelerometer <NUM> is a compact device designed to measure non-gravitational acceleration. When an accelerometer <NUM> goes from a standstill to any velocity, it is designed to respond to the vibrations associated with such movement. It uses microscopic crystals that go under stress when vibrations occur, and from that stress a voltage is generated to create a reading on any acceleration. A three-axis accelerometer <NUM> may be used to identify orientation, and thereby determine whether the orientation has changed from the orientation when the at least one flame detector <NUM> was arranged with its field-of-view covering the predetermined area.

If the at least one movement sensor <NUM> comprises a gyroscope <NUM>, the at least one processing device <NUM> may be arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area based at least on signals received from the gyroscope <NUM>. A gyroscope <NUM> is a device that uses gravity to help determine orientation. Its design consists of a freely-rotating disk called a rotor, mounted onto a spinning axis in the center of a larger and more stable wheel. As the axis turns, the rotor remains stationary to indicate the central gravitational pull. Since a gyroscope <NUM> determines orientation, it may be used to determine whether the orientation has changed from the orientation when the at least one flame detector <NUM> was arranged with its field-of-view covering the predetermined area.

If the at least one movement sensor <NUM> comprises an inertial measurement unit <NUM>, the at least one processing device <NUM> may be arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area based at least on signals received from the inertial measurement unit <NUM>. An inertial measurement unit (IMU) <NUM> is an electronic device that measures and reports a body's specific force and angular rate using a combination of accelerometers and gyroscopes. Since an inertial measurement unit <NUM> determines orientation, it may be used to determine whether the orientation has changed from the orientation when the at least one flame detector <NUM> was arranged with its field-of-view covering the predetermined area.

If the at least one movement sensor <NUM> comprises a direction sensing unit such as a compass <NUM>, the at least one processing device <NUM> may be arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area based at least on signals received from the compass <NUM>. Since a compass <NUM> determines orientation, it may be used to determine whether the orientation has changed from the orientation when the at least one flame detector <NUM> was arranged with its field-of-view covering the predetermined area. If it is desired to determine changes from an absolute compass direction, the compass <NUM> is preferably calibrated after installation of the flame detecting arrangement <NUM>, since deviation caused local magnetic fields may affect the compass <NUM>.

The flame detecting arrangement <NUM> also comprise an indicating means <NUM> that indicate whether the field-of-view of the flame detector <NUM> covers the predetermined area. The indicating means <NUM> are arranged together with the flame detector <NUM>, e.g. by being arranged on the same housing as the flame detector <NUM>. The indicating means <NUM> may e.g. be a laser aiming device, that e.g. aims at the center of the field-of view of the flame detector <NUM>. This enables the person installing the flame detector <NUM> to see where the center of the field-of view of the flame detector <NUM> will be. This may be very useful as an aid during installation of the flame detector <NUM>, but it may also be used during redirection of the flame detector <NUM> after an alert that the field-of view of the flame detector <NUM> may no longer cover the predetermined area.

In some situations, the position and orientation of the flame detector <NUM> may be pre-planned. If a new facility is planned for construction, the desired positions and orientations of flame detectors <NUM> may be pre-planned and specified in e.g. 3D drawings of the facility, so that the field-of-view of each flame detector <NUM> covers a relevant area where there is a fire hazard. In such situations, the pre-planned position and orientation may be pre-programmed into the at least one processing device <NUM> of the flame detecting arrangement <NUM>. If the flame detecting arrangement <NUM> comprises indicating means <NUM> in the form of e.g. a number of LEDs or one or more arrows, these could be used to indicate to the person making the installation how the flame detector <NUM> should be moved in order to be placed in the pre-planned position and orientation. Such indicating means <NUM> may also be used during redirection of the flame detector <NUM> after an alert that the field-of view of the flame detector <NUM> may no longer cover the predetermined area.

In order to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area, it is advantageous to during installation of the flame detector <NUM> store orientation data representing the orientation of the flame detector <NUM> when it is arranged with its field-of-view covering the predetermined area, so that the signals from the accelerometer <NUM>, gyroscope <NUM>, inertial measurement unit <NUM>, and/or compass <NUM> may be compared with these stored orientation data. Such a comparison may determine deviations that are larger than a predetermined amount from the stored orientation data, or it may determine deviations outside of a predetermined range set in relation to the stored orientation data. There may be an option to define such a range, e.g. during installation of the flame detector <NUM>, or via a control system <NUM> at a later stage. The range may also be defined by training the system through e.g. recording the movement over a certain time span, such as e.g. one hour, <NUM> hours, or a week, and setting the range based on defining all movement detected during this time span as normal movement.

The at least one processing device <NUM> may be arranged to only determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area after first detecting abnormal movement of the flame detector <NUM>.

The at least one processing device <NUM> may be arranged to determine whether the field-of-view of the flame detector <NUM> still covers the predetermined area using image processing software. Unless the flame detector <NUM> is image based, this may require the flame detecting arrangement <NUM> to comprise an image generating device.

<FIG> schematically illustrates a method <NUM> for an optical flame detector <NUM> arranged with its field-of-view covering a predetermined area. The method <NUM> comprises:.

Use of the method <NUM> allows for informing an operator/control system <NUM> if there is a risk that the field-of-view of the flame detector <NUM> to no longer covers the area where there is a fire hazard, so that the field-of-view of the flame detector can be corrected to the desired, preferably the original, field-of-view.

In embodiments, the receiving <NUM> comprises receiving the signals in a local processing device <NUM> arranged together with the flame detector <NUM>.

In embodiments, the at least one movement sensor <NUM> comprises a vibration sensor <NUM>. In embodiments, the receiving <NUM> comprises receiving signals from the vibration sensor <NUM>, the detecting <NUM> comprises detecting abnormal movement of the flame detector <NUM> based on these signals, and the alerting <NUM> comprises alerting an operator and/or a control system <NUM> if abnormal movement in the form of vibrations beyond a predetermined threshold are detected. This allows for detecting any kind of abnormal movement of the flame detector, even e.g. a mild push or shake, which may have caused the field-of view of the flame detector to no longer cover the predetermined area.

In embodiments, the at least one movement sensor <NUM> comprises at least one of: an accelerometer <NUM>; a gyroscope <NUM>; an inertial measurement unit <NUM>; and/or a direction sensing unit such as a compass <NUM>.

The method <NUM> further comprises: one or more of:.

The determining <NUM> of whether the field-of-view of the flame detector <NUM> still covers the predetermined area may be based at least on the signals received from the at least one movement sensor <NUM>.

In embodiments, the determining <NUM> of whether the field-of-view of the flame detector <NUM> still covers the predetermined area compares the signals received from the at least one movement sensor <NUM> with stored orientation data representing the orientation of the at least one flame detector <NUM> when it is arranged with its field-of-view covering the predetermined area. This is a simple way of determining whether the field-of-view of the flame detector still covers the predetermined area.

In embodiments, the determining <NUM> of whether the field-of-view of the flame detector <NUM> still covers the predetermined area takes place only after first detecting <NUM> abnormal movement of the flame detector.

In embodiments, the determining <NUM> of whether the field-of-view of the flame detector <NUM> still covers the predetermined area uses image processing software. Unless the flame detector <NUM> is image based, this may require the flame detecting arrangement <NUM> to comprise an image generating device.

Claim 1:
Flame detecting arrangement (<NUM>) comprising:
at least one optical flame detector (<NUM>), arranged with its field-of-view covering a predetermined area;
indicating means (<NUM>), arranged together with the at least one flame detector (<NUM>), wherein said indicating means (<NUM>) is arranged on a housing of the flame detector;
at least one movement sensor (<NUM>), arranged together with the at least one flame detector (<NUM>); and
at least one processing device (<NUM>), arranged together with the at least one flame detector (<NUM>), to:
receive signals from the movement sensor (<NUM>);
detect abnormal movement of the flame detector (<NUM>) based on these signals;
alert an operator and/or a control system (<NUM>) if abnormal movement of the flame detector (<NUM>) has been detected;
indicate, using the indicating means (<NUM>), how the at least one flame detector (<NUM>) should be oriented in order for its field-of-view to cover the predetermined area; and
display an alert using the indicating means (<NUM>) on the flame detecting arrangement (<NUM>).