Patent Description:
Life safety devices, such as commercial and/or industrial smoke detectors, often located inside of a housing or enclosure, use light scattering to detect the presence of a hazardous condition in the area being monitored. However, most conventional life safety devices are not capable of distinguishing between hazardous conditions and other nuisance conditions that typically occur, such as the presence of dust or steam adjacent the detector. False alarms are more likely to occur as a result of these other particles.

<CIT> discloses a hazard alarm, in particular a smoke alarm, that can be mounted on a wall or ceiling of a building. This alarm has at least one transmitting device and at least one receiving device which are configured to detect objects placed in its vicinity. <CIT> also discloses a hazard alarm with these features.

In one aspect of the invention, a device for detecting a hazardous condition in an area is provided, according to claim <NUM>.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter is configured to generate a frequency of approximately <NUM>.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter and the at least one extremely-high frequency receiver are located within the chamber.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter is located directly across the chamber from the at least one extremely-high frequency receiver.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter and the at least one extremely-high frequency receiver are located on an exterior of the housing.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter includes a plurality of extremely-high frequency transmitters. The at least one extremely-high frequency receiver includes a plurality of extremely-high frequency receivers.

In a further embodiment of any of the above, the plurality of extremely-high frequency transmitters are positioned in a non-line of sight configuration with the plurality of extremely-high frequency receivers.

In a further embodiment of any of the above, a portion of the housing includes a plurality of openings in fluid communication with the chamber and an exterior of the housing.

In a further embodiment of any of the above, the at least one smoke sensing device includes a photoelectric detector having a light source and a photoelectric sensor.

In a further embodiment of any of the above, the at least one smoke sensing device includes an ionization detector including a rotation source, a positive plate electrode, and a negative plate electrode.

In a further embodiment of any of the above, the at least one smoke sensing device includes a photoelectric detector and an ionization detector.

In a further embodiment of any of the above, the at least one extremely-high frequency transmitter includes a high frequency generator in communication with a transmitting antenna. The at least one extremely-high frequency receiver includes an antenna in electrical communication with a receiver with a lens for focusing EHF waves.

In another aspect of the invention, a method of operating a device for detecting a hazardous condition in an area is provided, according to claim <NUM>.

In a further embodiment of any of the above, the method includes determining the presence of water in the air by measuring a distortion of the signal generated by the at least one extremely-high frequency transmitter with the at least one extremely-high frequency receiver.

In a further embodiment of any of the above, the at least one smoke sensing detector includes at least one of a photoelectric detector or an ionization detector.

In a further embodiment of any of the above, the extremely-high frequency detector and the at least one smoke sensing detector are located within a chamber at least partially defined by a housing of the device.

In a further embodiment of any of the above, the device provides an alarm if the extremely-high frequency detector does not detect water in the air and if the at least one smoke sensing detector is triggered.

In a further embodiment of any of the above, the device does not provide an alarm if the extremely-high frequency detector detects water in the air and if the at least one smoke sensing device is triggered.

<FIG> illustrates an example detection device <NUM>. One feature of the detection device <NUM> is to reduce or eliminate false or nuisance alarms resulting from high number of water particles in the vicinity of the detection device as will be described in more detail below. The detection device <NUM> includes a housing <NUM> enclosing the internal electronics of the detection device <NUM> and a base <NUM> for attaching the detection device <NUM> to another structure such as a wall. The housing <NUM> also includes a plurality of inlets <NUM> located in a domed portion of the housing <NUM>. The inlets <NUM> provide fluid communication between an exterior of the housing <NUM> and an interior chamber <NUM> (<FIG>) that allows particles or smoke in the surrounding air to enter the detection device <NUM>.

<FIG> schematically illustrates an example of the various components (not shown to scale) within the detection device <NUM> used for detecting smoke <NUM> and other particles in the air, such as water particles <NUM>. In the illustrated example, the various components in the detection device <NUM> include a photoelectric detector <NUM>, an ionization detector <NUM>, and an extremely high-frequency ("EHF") detector <NUM> located within or adjacent the detection device <NUM>. Although the illustrated example depicts both the photoelectric detector <NUM> and the ionization detector <NUM>, an alternative detector may use only one of these two components in connection with the EHF detector <NUM> in the detection device <NUM>.

In the illustrated example, the photoelectric detector <NUM> includes a photoelectric transmitter <NUM>, such as a light source, located opposite a light catcher <NUM>. The light catcher <NUM> prevents or reduces light from originating from the photoelectric transmitter <NUM> to scatter within the housing <NUM>, rather light will scatter primarily from smoke <NUM> and water <NUM>. The photoelectric detector <NUM> also includes a photoelectric sensor <NUM> located outside of the normal path for light rays <NUM> emitted from the photoelectric transmitter <NUM> towards the light catcher <NUM>. A controller <NUM> is in electrical communication with the photoelectric transmitter <NUM> and programmed to trigger the generation of the light rays <NUM> and determine or measure the reception of the light rays <NUM> with the photoelectric sensor <NUM>. The controller <NUM> includes memory and a microprocessor to perform the programmed tasks described herein.

The photoelectric sensor <NUM> receives the light rays <NUM> transmitted from the photoelectric transmitter <NUM> that may be scattered by smoke <NUM> located within the chamber <NUM>. Although the photoelectric detector <NUM> is intended to identify smoke <NUM> within the chamber <NUM>, the presence of water particles <NUM> within the chamber <NUM> can also cause the light rays <NUM> to scatter and be received by the photoelectric sensor <NUM>. When the water particles <NUM> cause the light rays <NUM> to scatter, this could cause the controller <NUM> to trigger an alarm <NUM> in a traditional detection device. One feature of the present invention is to allow the device <NUM> to distinguish water <NUM> from smoke <NUM> and avoid the alarm <NUM> being triggered without the presence of smoke <NUM>.

The ionization detector <NUM> includes an ionization source <NUM>, a positive plate electrode <NUM>, and a negative plate electrode <NUM>. The ionization source <NUM> converts air molecules into positively and negatively charged ions and because opposite charges attract, the negatively charged ions move towards the positive plate electrode <NUM> and the positively charged ions move towards the negative plate electrode <NUM>. The movement of positively and negatively charged ions completes a circuit in the ionization detector <NUM> by allowing electricity to flow between the positive plate electrode <NUM> and the negative plate electrode <NUM>. The controller <NUM> is in electrical communication with the positive plate electrode <NUM> and the negative plate electrode <NUM> and can measure changes in electrical flow between the positive and negative plate electrodes <NUM>, <NUM> resulting from changes in an ion flow <NUM>.

When smoke <NUM> or water particles <NUM> enter the chamber <NUM>, the ions from the ionization source <NUM> bond with the smoke <NUM> or the water particles <NUM>. When the ions bond with the smoke <NUM> or the water particles <NUM> instead of the positive and negative plate electrodes <NUM>, <NUM>, there is a reduction of electrical flow in the circuit of the ionization detector <NUM> that is measurable by the controller <NUM>. Because both the smoke <NUM> and the water particles <NUM> can bond with the ions, in a traditional detection device the controller <NUM> could trigger the alarm <NUM> based on the presence of water particles <NUM> located in the chamber <NUM> and not smoke <NUM>. In the absence of smoke particles <NUM> it is desirable to avoid the alarm <NUM> being triggered in the presence of the water particles <NUM>, which is accomplished with the method further explained below.

Although the photoelectric detector <NUM> and the ionization detector <NUM> are each capable of identifying the presence of smoke <NUM> within the chamber <NUM>, other substances that may enter the chamber <NUM> can cause the photoelectric detector <NUM> and/or the ionization detector <NUM> to indicate the presence of smoke <NUM> within the chamber <NUM> as described above. When the photoelectric detector <NUM> and the ionization detector <NUM> incorrectly identify the presence of smoke <NUM> within the chamber <NUM>, this creates a situation referred to as a "nuisance alarm. " The nuisance alarm is a situation where the detection device <NUM> may sound the alarm <NUM> without the presence of smoke <NUM>. As discussed above, water particles <NUM> in the chamber <NUM> can lead the controller <NUM> to believe that there is smoke <NUM> within detection device <NUM> when using either the photoelectric detector <NUM>, the ionization detector <NUM>, or both.

In order to reduce the possibility of false or nuisance alarms, the detection device <NUM> includes the EHF detector <NUM> in communication with the controller <NUM> to validate the determination by either the photoelectric detector <NUM> or the ionization detector <NUM> of the presence of the smoke <NUM>. The EHF detector <NUM> provides validation by identifying the presence of the water particles <NUM> in the vicinity of the detection device <NUM>. The EHF detector <NUM> includes an EHF transmitter <NUM> having an EHF generator capable of generating an EHF wave <NUM> and transmitting the EHF wave with an antenna. In one example, the extremely high frequency generated by the EHF transmitter is between <NUM> and <NUM> and in another example, the extremely high frequency is approximately <NUM>. The EHF waves <NUM> might be transmitted through pulses or by a constant stream of waves. In the illustrated example, the EHF detector <NUM> also includes an EHF receiver <NUM> located directly across from the EHF transmitter <NUM> having a lens <NUM> and an antenna for receiving the EHF waves <NUM> with a receiver.

The EHF detector <NUM> detects water particles <NUM> without receiving interference from the smoke <NUM> by generating the EHF waves <NUM> with the EHF transmitter <NUM>. Because the frequency generated by the EHF transmitter <NUM> is so high, the EHF waves <NUM> encounter little or no interference from the smoke particles <NUM> within the chamber <NUM>. Therefore, when smoke <NUM> is present inside the chamber <NUM>, the EHF receiver <NUM> measures little or no reduction in signal of the EHF waves <NUM> generated by the EHF transmitter <NUM>. As shown in <FIG>, the EHF receiver <NUM> may include a lens <NUM> for focusing the EHF waves <NUM>. However, the water particles <NUM> are able to absorb or reflect the EHF waves <NUM> to a greater degree than the smoke <NUM>. To determine the presence of the water particles <NUM> the controller <NUM> identifies the variation in the EHF waves <NUM> from an expected value compared to a measured value of sensors <NUM> and/or <NUM>, <NUM>.

The controller <NUM> utilizes the information gathered by the photoelectric detector <NUM>, the ionization detector <NUM>, and the EHF detector <NUM> to determine whether or not the alarm <NUM> should be provided and eliminates or greatly reduces the number of nuisance alarms provided by the detection device <NUM>. The alarm <NUM> can include at least one of an audio or visual indicator or the alarm <NUM> can communicate with a remote location to indicate the presence of the smoke <NUM> in the vicinity of the detection device <NUM>.

<FIG> illustrates a schematic view of another example detection device 20A. The detection device 20A is similar to the detection device <NUM> except where described below or shown in the Figures. In particular the detection device 20A includes the photoelectric detector <NUM> having the photoelectric transmitter <NUM> opposite the light catcher <NUM> with the photoelectric sensor <NUM> for measuring distortions of the light rays <NUM> as described above. Additionally, the detection device 20A includes the ionization detector <NUM> having the ionization source <NUM> with the positive and negative plate electrodes <NUM>, <NUM> that measure variations in the ion flow <NUM> resulting from the smoke <NUM> or water particles <NUM> as described above.

However, the detection device 20A includes an EHF detector 52A located on an exterior of the housing <NUM>. The EHF detector 52A includes multiple EHF transmitters 54A and multiple EHF receivers 56A with a lens 61A for directing EHF waves 62A into the EHF receiver 56A. However, the multiple EHF transmitters 54A and the multiple EHF receives 56A are oriented in a non-line of sight configuration on the exterior of the housing <NUM>, such that the none of the multiple EHF transmitters 54A are pointed directly at any of the multiple EHF receivers 56A. Similar to the EHF detector <NUM> described above, the EHF receivers 56A measure a reduction in the EHF waves 62A that are absorbed or distorted by the water particles <NUM>. The controller <NUM> is programmed to determine when the EHF waves 62A received by the EHF receivers 56A correspond to a reduction in the signal of the EHF waves 62A resulting from the water particles <NUM> in the vicinity of the detection device 20A as opposed to the EHF waves 62A reflecting off of adjacent structures such as walls.

<FIG> illustrates an example method <NUM> for operating either of the detection devices <NUM>, 20A described above. The method <NUM> includes determining if smoke <NUM> is detected in the chamber <NUM>. (Step <NUM>). The determination of the presence of smoke <NUM> within the chamber <NUM> is made with the controller <NUM> monitoring at least one of the photoelectric detector <NUM> or the ionization detector <NUM> as described above. If the photoelectric detector <NUM> or the ionization detector <NUM> detects the presence of smoke <NUM> as determined by the controller <NUM>, then the detection devices <NUM>, 20A will determine if water particles <NUM> are detected in the air surrounding the detection device <NUM>, 20A. (Step <NUM>).

The controller <NUM> in the detections devices <NUM>, 20A determines if water particles <NUM> are in the air through monitoring a respective one of the EHF detectors <NUM>, 52A, as described in more detail above. If it is determined by the controller <NUM> in communication with one of the EHF detectors <NUM>, 52A that water particles <NUM> are present in the air, then the detection devices <NUM>, 20A will not provide an alarm. (Step <NUM>). If it is determined by the controller <NUM> in communication with one of the EHF detectors <NUM>, 52A that water particles <NUM> are not present in the air, then the detection devices <NUM>, 20A will provide the alarm <NUM>. (Step <NUM>).

If smoke <NUM> is not detected in the chamber <NUM> by at least one of the photoelectric detector <NUM> or the ionization detector <NUM>, the controller <NUM> in the detections devices <NUM>, 20A will determine if water particles <NUM> are present in the air through monitoring a respective one of the EHF detectors <NUM>, 52A. (Step <NUM>). If water particles <NUM> are in the air, the detection devices <NUM>, 20A will not provide an alarm. (Step <NUM>). Furthermore, if water particles <NUM> are not in the air, the detection devices <NUM>, 20A will not provide an alarm. (Step <NUM>).

Although the different non-limiting embodiments are illustrated as having specific components, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments.

Claim 1:
A device (<NUM>) for detecting a hazardous condition in an area, comprising:
a housing (<NUM>) defining a chamber (<NUM>); and
at least one smoke sensing device (<NUM>, <NUM>) for detecting the presence of smoke (<NUM>) in the chamber (<NUM>),
characterised by further comprising:
an extremely-high frequency detector (<NUM>) including at least one extremely-high frequency transmitter (<NUM>) and at least one extremely-high frequency receiver (<NUM>), wherein the at least one extremely-high frequency transmitter (<NUM>) is configured to generate a frequency between <NUM> and <NUM> for detecting if water (<NUM>) is present in the air adjacent the device (<NUM>);
wherein the device is configured to determine if an alarm (<NUM>) should be triggered to indicate a hazardous condition based on the extremely-high frequency detector (<NUM>) and the at least one smoke sensing device (<NUM>, <NUM>).