Signals and indicators – Alarms – Fluid-pressure variation
Reexamination Certificate
2000-12-26
2002-07-02
Gutierrez, Diego (Department: 2859)
Signals and indicators
Alarms
Fluid-pressure variation
C116S13700R, C116S06700A, C116S1420FP, C116SDIG002
Reexamination Certificate
active
06412435
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a noise producing device responsive to air flow. More specifically, the invention is a reusable filter whistle made reliable through its dustproof design and adjustable in the degree of sensitivity to airflow permitted before whistling and adapted for use with a furnace or an air conditioning assembly in any position.
2. Description of the Related Art
The related art of interest in a crowded art describes various indicator devices, but none discloses the present invention. There is a need for a dependable, ergonomic and inexpensive warning device adjustable in sensitivity to add to a filter to indicate the filter is dirty and requires replacement. The related art will be described in the order of perceived relevance to the present invention. installed in a gridded fiberglass air filter to signal a predetermined 60-70% clogged air filter. The whistle has two circular molded plastic parts which interfit as follows. The upstream part is cup-shaped with a flange for compressing the filter's grid and a tubular lip surrounding the bottom wall of the first part. The bottom wall of the cup has an orifice which is aligned with an orifice in a recessed portion of the downstream whistle part. The flanged portion of the downstream part interfits with the lip of the upstream part. A typical rated flow resistance of a new filter is about 0.02 inch H
2
O. At a pressure drop of 0.23 to 0.25 inch H
2
O, the whistle will emit a soft tone. At 0.5 inch H
2
O, the whistle will emit a loud shrill tone. The viscous throw-away filter is replaced. A dry type reusable filter can be shaken or vacuumed. The whistle device is distinguishable for its two-part construction requiring alignment of the two orifices.
U.S. Pat. No. 2,753,831, issued on Jul. 10, 1956 to Walter B. Davies, describes an air filter clogging warning apparatus comprising a whistle inserted in a filter. The whistle apparatus is configured as a hollow capsule, the whistle, per se, being a double-walled device having aligned holes, the whistle being positioned in a tube with a funnel-shaped entrance between the funnel portion and a tubular neck portion having a diameter two hundred times larger than the holes. The whistle apparatus is distinguishable for its funnel structure with a double-walled whistle.
U.S. Pat. No. 5,352,255, issued on Oct. 4, 1994 to Andrew A. Taft, describes a noise maker for an air filter comprising a permanently coupled rectangular housing with two aligned holes and having a weighted member in resilient relationship over one hole in the housing. The weighted member is slidably mounted on a dowel rod within the housing. A slider plate is provided with a plurality of hole sizes and interposed between one hole and the weighted member. The device is distinguishable for its multiple parts and intricate structure.
U.S. Pat. No. 5,057,821, issued on Oct. 15, 1991 to Gary C. Card, describes a filter sentry apparatus which emits an audible alarm by actuating a switch within a housing. A housing secured to a filter web includes a reciprocating rod directed through the housing. When the filter web becomes plugged, the rod actuates a magnet to track a plurality of contacts of a switch to effect an audible and visual alarm. In addition, an on/off switch is provided. The apparatus is distinguishable for its electrical structure.
U.S. Pat. No. 5,325,809, issued on Jul. 5, 1994 to Theodore B. Mulle, Jr., describes a hair dryer with an alarm notifying the user of a clogged filter. A whistle containing a reed is centered in the air inlet of the hair dryer. The whistle is distinguishable for its required reed structure.
U.S. Pat. No. 5,772,711, issued on Jun. 30, 1998 to Joseph W. Kieffer, describes a filter blockage warning indicator for a portable turbine of a spray paint gun system. A visual indicator comprising a lamp is actuated by a predetermined filter blockage of 75%. An audible indicator in place of the visual indicator is coincidently described, but its structure is not explained.
U.S. Pat. No. 4,747,364, issued on May 31, 1988 to Barry N. Horowitz, describes a flow rate threshold sensor for use with an air filter which channels air flow to energize an audible sound generator upon development of an air pressure differential within the sensor above a settable threshold, resulting from a clogged air filter. The sensor includes a magnetically retained disk, which disk in combination with a cap of the sensor, defines a first chamber having an air pressure commensurate with that of the upstream side of an associated air filter. A second chamber defined by the disk and the base of the sensor is in fluid communication through an aperture in the base with the downstream side of the air filter to establish within the second chamber an air pressure with that present at the downstream side of the disk. Upon development of a sufficient pressure differential between the first and second chambers, the disk will be displaced from the magnet and permit air flow from the first chamber to the second chamber in response to the pressure differential. Air flow response means extend across the aperture in the base and become energized in response to air flow through the aperture to provide an audible tone indicative of the pressure differential threshold being exceeded. Means are provided to alter the degree of magnetic force acting upon the disk and to permit altering the threshold being exceeded. Means are provided to alter the degree of magnetic force acting upon the disk and to permit altering the threshold level. The sensor device is distinguishable for relying on a magnetic response.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a dirty filter indicator solving the aforementioned problems is desired.
SUMMARY OF THE INVENTION
The present invention is an improvement of a reusable filter whistle device, now having a canopy, rendering the whistle device dustproof, the device being adapted for use in an air filter for a furnace, an air conditioning assembly and the like, the filter being positionable in any position, e.g., vertical, horizontal, upside down. As the filter collects dirt and dust, the airflow is restricted, causing more air to flow through the whistle device. This increased air flow through the device audibly alerts the occupants to the need to change the air filter. The whistle has a protective canopy and an adjustable point at which the whistle will occur by checking the degree of dirtiness of the filter and cutting off a portion of the whistle to make the adjustment.
Accordingly, it is a principal object of the invention to provide a device warning occupants of a dwelling that an air filter needs replacement or cleaning.
It is a further object of the invention to provide an audible warning device adjustable in degree to indicate an air filter needs replacement.
Still another object of the invention is to provide a small warning device with a protective canopy which can be placed in the air filter.
Another object of the invention is to provide an air filter monitoring device which emits a whistle when a furnace air filter becomes dirty or clogged, the monitoring device having a canopy to prevent dust or dirt particles from clogging the whistle.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
REFERENCES:
patent: 1863456 (1932-06-01), Smith
patent: 2682250 (1954-06-01), Ulrich
patent: 2753831 (1956-07-01), Davies
patent: 3736900 (1973-06-01), Nowicki
patent: 3740931 (1973-06-01), Nowicki
patent: 4215646 (1980-08-01), Williams
patent: 4321070 (1982-03-01), Bede
patent: 4747364 (1988-05-01), Horowitz
patent: 5057821 (1991-10-01), Card
p
Gutierrez Diego
Litman Richard C.
Reis Travis
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