Patent Publication Number: US-2021164771-A1

Title: System and method for detecting particle accumulation on a surface

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates to detection of particle. More specifically, the present disclosure is concerned with a system and method for detecting particle accumulation on a surface. 
     BACKGROUND OF THE DISCLOSURE 
     In industrial or commercial buildings dust needs to be controlled so as to reduce dust explosion hazards. 
     Dust and particles accumulation may be detected by visual inspection or measurements in a building, and cleaning operation scheduled on a regular basis or depending on the visually observed level of deposition. 
     Control surfaces accumulating dust and particles positioned at places within the building may be visited on a regular basis so as to assess dust and particles buildup. Test films coated with an adhesive layer may be used to collect dust and particles from control surfaces for analysis. 
     There is a need in the art for a system and method for detecting particle accumulation on a surface. 
     SUMMARY OF THE INVENTION 
     More specifically, in accordance with the present invention, there is provided a system for monitoring matter accumulation on a surface, comprising an emitter emitting a flat or line beam parallelly to a surface to be monitored at a predetermined height above the surface to be monitored; a receiver positioned at the predetermined height above the surface to be monitored, the receiver being selected to one of: i) configured to detect a reflected beam and ii) configured to detect a transmitted beam, and a signaling unit sending a signal indicating that a threshold thickness of matter has accumulated on the surface to be monitored when one of: i) the receiver starts detecting a reflected beam and ii) the receiver stops detecting a transmitted beam. 
     There is further provided a method for monitoring matter accumulation on a surface, comprising emitting a flat or line beam generally parallelly to a surface to be monitored at a predetermined height above the surface to be monitored; monitoring a variation in one of: i) transmission and ii) reflection of the beam at the predetermined height above the surface to be monitored and emitting a signal indicating that a threshold thickness of matter has accumulated on the surface to be monitored when said monitoring the variation in one of: i) transmission and ii) reflection of the beam at the predetermined height above the surface to be monitored indicates one of: i) stop of the transmission and ii) start of the reflection. 
     There is further provided a method comprising positioning a light beam source in relation to a target threshold height of matter accumulation to be detected on a surface, emitting a flat or line beam parallel to the surface, one of: i) detecting a reflected beam at the position of the light beam source and ii) detecting absence of a transmitted beam at a position opposite the light beam source across the surface being monitored; and triggering a signal. 
     There is further provided a system comprising an emitter directing a flat detection beam parallel to an accumulation surface, at a predetermined height from the surface as set by a positioning device, and a receiver positioned at the predetermined height from the surface and receiving a reflected or a transmitted beam, indicative of a height of matter being accumulated on the surface. 
     Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the appended drawings: 
         FIG. 1  is a schematic view of a system according to an embodiment of an aspect of the present disclosure; 
         FIG. 2  is a schematic view of operation of a system according to an embodiment of an aspect of the present disclosure; 
         FIG. 3  shows a positioning device according to an embodiment of an aspect of the present disclosure; 
         FIG. 4  is an exploded view of the positioning device of  FIG. 3 ; 
         FIG. 5  shows a system according to an embodiment of an aspect of the present disclosure; 
         FIG. 6  shows a system according to another embodiment of an aspect of the present disclosure; 
         FIG. 7  shows a system according to another embodiment of an aspect of the present disclosure; 
         FIG. 8  shows a system according to another embodiment of an aspect of the present disclosure; 
         FIG. 9  shows a system according to another embodiment of an aspect of the present disclosure; 
         FIG. 10  is an exploded view of the system of  FIG. 9 ; and 
         FIG. 11  shows positioning of the system of  FIG. 9  on a beam. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The present disclosure is illustrated in further details by the following non-limiting examples. 
     A system  100  according to an embodiment of an aspect of the present disclosure as illustrated in  FIGS. 1 and 2  for example, comprises a unit  101  emitting a flat or line beam  102  generally parallelly to a surface  103 , i. e. at an angle of about 0° relative to the top plan of the surface  103 , at a height (h) above the surface  103 . In absence of matter on the path of the beam  102  on the surface  103  above the height (h), no signal is sent back to the unit  101  (see  FIG. 1 ). A soon as the thickness of matter  104  accumulated on the surface  103  reaches the height (h) on the surface  103  as shown in  FIG. 2  for example, a part  105  of the beam  102  is reflected back to the unit  101 . In return, the unit  101  emits a signal indicating that a threshold accumulation of matter, dust or particles, as detected using the relative position between the unit  101  and the surface  103  as indicated by the height (h) of the beam  102  above the surface  103 , on the monitored surface  103 . 
     The unit  101  may be a photoelectric device, comprising an emitter and a receiver and driven by a power source, so that when matter accumulating on the monitored surface  103  reaches the threshold thickness (h), at least part of the light beam sent by the emitter is returned and detected by the receiver, which in turn triggers a signal via a signaling unit such as an antenna secured to the casing of the unit  102  for example, and emitting to a WIFI antenna of the premises (not shown) 
     Matter accumulation on the surface may thus be monitored, by preselecting the height (h) above the surface  103  of emission of the flat or line beam generally parallelly to the monitored surface, independently of the density of the accumulation on the surface, which may vary across the surface that is being monitored. 
     A positioning device may be used to select the relative position between the unit  101  and the surface being monitored, i. e. the height (h) of the beam  102  above the surface  103  in examples of  FIGS. 1 and 2 . The height (h) is selected so as to detect a target thickness of matter accumulated on the surface being monitored. 
     According to an embodiment of an aspect of the present disclosure illustrated in  FIGS. 3-4 , a positioning device  200  comprises a base plate  201  supporting a housing mounted on a support  202 . The unit  101  is held within the housing, which comprises a window  204  in a front surface thereof for passage of emitted beams  102  and reflected beams  105  by the unit  101 . 
     In a example illustrated in  FIG. 4 , the support  202  is secured to the base plate  201  by screws  211  for example. The support  202  comprises a slot  213  receiving the foot of a T-shape member  207 . A cover  203  is secured to the top arms of the T-shape member  207  (see screws  208 ). A bolt  209  is positioned from above the cover  203  within the foot of the T-shape member  207 , a distal end thereof being secured in the threaded bottom end of the foot of the T-shape member  207  by nuts  210  for example, or by a combination of a nut  210  and a plastic ring for example, allowing free rotation of the bolt  209  for raising and lowering the T-shape member  207  within the slot  213  of the support  202 . 
     The housing to receive the unit  101  is formed by a spacing plate  205  supported by screws  206  from the top surface of the cover  203  and the cover  203  for example. 
     Once thus assembled, the positioning device  200  may be used to adjust the height of the unit  101 , by rotation of the bolt  209 , thereby lifting or lowering the cover  203 , and the unit  101  within the housing, from and to the base plate  201 , in relation to the surface  103  to be monitored as illustrated in  FIG. 5 , thereby setting the detection threshold. 
     Alternatively, a reference gauge, such as a plate of a thickness corresponding to the threshold height (h) of accumulated dust to be detected, may be used for precise positioning of the unit  101  relative to the surface  103 . The reference gauge is positioned directly on the surface to be monitored surface  103 , and the unit  101  is positioned in relation to the gauge at the minimum height above the surface to be monitored surface  103  at which the beam  102  starts to be reflected back by hitting the gauge wall; then, the gauge is removed from the surface to be monitored surface  103 . When accumulation  104  on the surface  103  reaches a height corresponding to the gauge, part of the beam  102  emitted by the unit  101  is then reflected back and an alarm is triggered. 
     Alternatively, the unit  101  may be positioned at a fixed location in relation to a movable test surface, and the vertical distance between the top of the test surface and the beam emitted by the unit  101  is adjusted to the predetermined threshold height (h) of accumulated dust to be detected by moving the test surface vertically (see for instance  FIG. 8  discussed hereinbelow). 
     Calibration parameters of the unit  101  may need to be adjusted, depending of the nature of the accumulated matter. For example the index of reflection of the dust may vary according to the nature of the product contained in the dust, wood such as maple having a reflection index of 0.55 to 0.65 while concrete may have a reflection index of 0.4 to 0.5 for instance. Thus, the unit  101  is selected or adjusted in sensitivity depending on the nature of matter under monitoring so that the alarm is indeed triggered when accumulation thereof reaches the predetermined height h. 
     The calibration of the beam emitted above the surface to be monitored allows to adjust the capture distance of the unit  101 , i. e the propagation distance of the emitted beam, i.e. the sensing range of the unit  101  so as to avoid false alarm by detection of the presence of nearby objects, such as a beam fin the environment for example. 
       FIG. 6  shows a system according to another embodiment of an aspect of the present disclosure. The system  400  comprises a positioning device  200  as described hereinabove in relation to  FIG. 3  for example, positioning the unit  101  on the base plate  201  in relation with a test surface  103 ′. In the same way as described in relation to  FIG. 2  for example, the surface that accumulates matter is the test surface  103 ′ and when the accumulation height on the test surface  103 ′ reaches the height (h) of the beam emitted by the unit  101  above the test surface  103 ′, the unit  101  receives a reflected beam  105  and sends a signal to a wireless emitter (not shown) that is located within a housing below the test surface  103 ′, which in turn may send a remote signal via a router and an alert may be sent by internet for example. 
     The detecting light beam source and the detector of reflected beam may be a same device as described hereinabove or separate devices located at the same height (h) relative to the surface relative to the surface to be monitored. Still alternatively, the light beam source and the light beam detector may be separate devices, arranged in a facing relationship on opposite edges of the surface to be monitored for example, at the height (h) relative to the surface; in this case, when the accumulation of matter on the surface to be monitored reaches the predetermined threshold height (h), the beam emitted by the light beam source on a first side is blocked by the matter accumulated above the height (h) on the surface being monitored and thus the detector on the opposite side stops receiving a signal, thereby triggering an accumulation signal. 
     As schematically illustrated in  FIG. 7 , a monitoring system  500  according to an embodiment of an aspect of the present disclosure comprises the system  400  connected to a router  501  allowing data collection and transfer via an internet network. 
       FIG. 8  shows a system  600  comprising a turntable  601  pivotally mounted on a top surface of a casing housing a wireless emitter (not shown) as described in relation to  FIG. 6  for example using a nut and threaded rod combination  602  according to an embodiment of an aspect of the present disclosure. The turntable  601  is adjustable in height above the top surface of the emitter  401  in order to calibrate the position of the unit  101 , the support  603  being fixed and maintaining the unit  101  at a fixed height. In this embodiment, the top surface of the turntable  601  is the test surface on which dust accumulation is monitored. 
     In an embodiment illustrated in  FIGS. 9-11 , a system is shown with a positioning clamp  701  according to an embodiment of an aspect of the present disclosure. As described hereinbefore, the unit  101  is referenced in height relative to the test surface  103 ′. 
     The clamp  701  may be fastened to the base plate  201  by a wing nut  702  and bolt  703  arrangement for example ( FIGS. 9, 10 ) and used to position the system in the environment as illustrated for example in  FIG. 11 . 
     As detailed in  FIG. 10 , the base plate  201  may comprise an extension at the base  709  thereof, for connection of the clamp  701  by a hinge joint  709 / 710  via a bolt  708  which passes through cavities  709 / 710  of the joint and is held by a clamping nut  711 , for example. 
     The clamp  701  may be further secured using the bolt  703  passing through a half-cylinder  704  through a cavity  705  of the extension of the base  709  of the box of the emitter  401  and through the joint  709 / 710  down a cavity  706  in the clamp  701  not shown, where it engages a locking ball  707  held in position by the wingnut  702 . The clip  701  may be disconnected from the system base plate  201  and thus from the unit  101  and the test surface  103 ′ in cases the system does not require anchoring. In addition the clip ( 701 ) may be of different size to accommodate the fixation under different conditions. 
       FIG. 11  illustrates the system  700  held in position relative to a I-beam  801  in an environment to be monitored by the clamp  701 . 
     A method according to an embodiment of an aspect of the present disclosure comprises positioning a light beam source in relation to a target threshold height (h) of matter accumulation on a surface, emitting a flat or line beam parallelly at the height (h) above the surface, detecting a reflected beam at the position of the light beam source or absence of a transmitted beam at a position opposite the light beam source across the surface being monitored; and in return causing an alarm to be sent. 
     The word dust used herein may encompass particles of different sizes, contaminants, or matter accumulating on a surface. The present system and method may be applied to accumulation of a solid or a viscous matter such as a viscous liquid on a surface, or a gas provided it may reflect the beam emitted by the unit  101 . 
     There is thus provided a system comprising an emitter directing a flat detection beam parallel to an accumulation surface, at a predetermined height (h) from the surface as set by a positioning device, and a receiver positioned at the predetermined height from the surface and receiving a reflected or a transmitted beam, indicative of a height (h) of matter being accumulated on the surface. 
     There is thus provided a system comprising a dust accumulation detector and an alarm signaling when a preset accumulation threshold is reached, allowing an autonomous monitoring of dust accumulation in industrial or commercial buildings, setting the threshold height according to regulations, such as a 3 mm allowance (⅛ inches) for example when dealing with insurance companies. The alarm may be any one of an audio or visual signal, or a combination thereof, for example. 
     The scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.