Clogged filter detector
First Claim
1. A clogged filter detector for determining a level of obscuration of a flat filter disposed in an air conditioning system, said filter having a body and a peripheral frame and said system comprising a filter receptacle carried in a duct or plenum thereof, said receptacle including a plurality of rigid plates having surfaces generally parallel to a direction of air flow and defining outer walls of a structure into which a said filter may be removably inserted and retaining ledges connected to said plates and disposed perpendicular thereto, said plates and said ledges being adapted to come into contact with a said frame upon insertion of a said filter, said detector comprising:
- an optical transmitter positioned to transmit a beam of light through a said filter,a receiver including a sensor disposed to be contacted by said light beam after passing through said filter and further including means to provide an electrical signal representative of optical transmittance through said filter, said receiver and said filter aligned off-set from one another and said light beam non-parallel to air flow direction, andsupport means for holding said transmitter and said receiver in an aligned position with respect to a selected area of said filter, said support means including a bracket comprising at least a first strip connectable to a said receptacle plate and said first strip being disposed for placement between a said plate and an edge portion edge of said filter upon insertion of the filter, and a first arm connected to said first strip and extending to a position opposing a face of said filter.
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Accused Products
Abstract
A clogged filter detection system has an optical transmitter (32) aligned to pass light through an air filter (14) of an HVAC air flow plenum, a receiver (34) including a sensor and positioned to receive the transmitted light (48) directly or from a reflector (42), a processing assembly (35) receiving signals from the sensor and communicating a visual (104) or audible (106) indication when an accumulated level of obscuration exceeds a predetermined level and a component support structure. The support structure uses a “U” or “L” shaped bracket (60,63) attached to peripheral structure of a filter receptacle frame (12) and one or more side plates (24,26) of the bracket are connected to an arm (74,76) on which components are carried. The transmitter (32) and receiver (34) may be located on opposite sides of the filter (14) or on the same side, with a retroreflector (46) on the other side. The processing assembly includes a microprocessor (94) and related devices. Measures are also provided for counteracting the presence of fluffy material near the filter, for sensitivity control of sensors and for an aural signal device activated at a predetermined time after a visual indication.
59 Citations
23 Claims
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1. A clogged filter detector for determining a level of obscuration of a flat filter disposed in an air conditioning system, said filter having a body and a peripheral frame and said system comprising a filter receptacle carried in a duct or plenum thereof, said receptacle including a plurality of rigid plates having surfaces generally parallel to a direction of air flow and defining outer walls of a structure into which a said filter may be removably inserted and retaining ledges connected to said plates and disposed perpendicular thereto, said plates and said ledges being adapted to come into contact with a said frame upon insertion of a said filter, said detector comprising:
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an optical transmitter positioned to transmit a beam of light through a said filter, a receiver including a sensor disposed to be contacted by said light beam after passing through said filter and further including means to provide an electrical signal representative of optical transmittance through said filter, said receiver and said filter aligned off-set from one another and said light beam non-parallel to air flow direction, and support means for holding said transmitter and said receiver in an aligned position with respect to a selected area of said filter, said support means including a bracket comprising at least a first strip connectable to a said receptacle plate and said first strip being disposed for placement between a said plate and an edge portion edge of said filter upon insertion of the filter, and a first arm connected to said first strip and extending to a position opposing a face of said filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 21)
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15. A clogged filter detector for determining a level of obscuration of a filter in an air circulation system and providing a perceptible indication when said level exceeds a predetermined level, said filter having a body and a peripheral frame and said system comprising a filter receptacle carried in a duct or plenum thereof, said receptacle including a plurality of rigid plates having surfaces generally parallel to a direction of air flow and defining outer walls of a structure into which a said filter may be removably inserted and retaining ledges connected to said plates and disposed perpendicular thereto, said plates and said ledges being adapted to come into contact with a said frame upon insertion of a said filter, said detector comprising:
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an optical transmitter positioned to transmit a beam of light through a said filter, a receiver including a sensor disposed to be contacted by said light beam after passing through said filter, a processing assembly further comprising a microprocessor having a digital memory in which a predetermined level of obscuration has been entered, means for converting a detected optical signal to electrical form, digitizing the resulting electrical signal and comparing the detected signal level with said predetermined level and for providing perceptible indication when said detection signal level drops below said predetermined level, and support means for holding said transmitter and said receiver in an aligned position with respect to a selected area of said filter, said support means including a bracket comprising a first strip conforming to a said receptacle plate and at least one side strip connected to a said ledge and said first strip being disposed between a said plate and a side edge of a said filter upon insertion of the filter, and a first arm connected to said side strip and extending to a position opposing a face of said filter. - View Dependent Claims (16, 17, 18, 19, 22, 23)
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20. A clogged filter detector for determining a level of obscuration of a filter disposed in an air conditioning system, said filter having a body and a peripheral frame and said system comprising a filter receptacle carried in a duct or plenum thereof, said receptacle including a plurality of rigid plates having surfaces generally parallel to a direction of air flow and defining outer walls of a structure into which a said filter may be removably inserted and retaining ledges connected to said plates and disposed perpendicular thereto, said plates and said ledges being adapted to come into contact with a said frame upon insertion of a said filter, said detector comprising:
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an optical transmitter positioned to transmit a beam of light through a said filter, a receiver including a sensor disposed to be contacted by said light beam after passing through said filter and further including means to provide an electrical signal representative of optical transmittance through said filter, and support means for holding said transmitter and said receiver in an aligned position with respect to a selected area of said filter, said support means including a first arm attached to a said retaining ledge and at least one side strip connected to a said rigid plate and a second arm attached to said side strip and upon insertion of the filter, movable into aligned position with respect to said transmitter and said receiver.
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Specification