Background

Airborne dust particles are a significant problem in many workplaces. Whenever people inhale airborne dust at work, they are at risk of occupational disease. Overexposure to dusts causes disease, temporary and permanent disabilities and deaths. Dusts in the workplace may also contaminate or reduce the quality of products, be the cause of fire and explosion, and damage the environment. Limiting the work area of dusts are extremely important for the health of employees and as well as the quality of work. There are several dust collectors currently available that are used at the point of dust creation however dust particles are still emitted into the air. There are other airborne dust collectors on the market as well, however they require daily or weekly maintenance to keep them working properly and they do not circulate a sufficient amount of air. What is presented is a self-maintaining airborne dust collector that addresses these problems.

Summary

A self-maintaining air filtration device comprises an enclosure having at least one open face and at least one air channel. A perforated screen covers each open face of the enclosure. A filter roll mounted to the enclosure comprises a length of filter media. A drive tube is mounted to the enclosure on the opposite side from the filter roll. A portion of the length of the filter media is pulled from the filter roll, over the perforated screen, and attached to the drive tube. When the drive tube is actuated, it pulls a new portion of the length of the filter media from the filter roll over the perforated screen. An air current inducer inside the enclosure draws air l through the air channel, such that air is drawn into or expelled out of the enclosure through the perforated screen and is filtered by the filter media that covers the perforated screen.

Each actuation of the drive tube covers the perforated screen with a new portion of the length of the filter media from the filter roll. The drive tube could be actuated manually or with a timer. The drive tube is driven by a stepper motor, servo motor, or a DC motor with a rotary encoder. The enclosure could have a plurality of open faces covered by the perforated screen. The air current inducer could be a fan, an air multiplier, or an air pump. A pressure sensor could be located inside the enclosure for actuating the drive tube when the pressure inside the enclosure surpasses a preset threshold. A misting system could also be incorporated to spray liquid onto filter media to improve filter performance and optionally to sanitize the air flowing through the system.

What is also presented is self-maintaining air filtration system for a building having at least one room. An air intake duct extending through each room of the building with a plurality of input vents distributed along the intake duct. Each input vent comprises a perforated screen that covers the input vent, a filter roll mounted to one side of each input vent comprising a length of filter media, and a drive tube mounted on the opposite side from the filter roll such that a portion of the length of the filter media is pulled from the filter roll over the perforated screen and attached to the drive tube. When the drive tube is actuated, it pulls a new portion of the length of the filter media from the filter roll over the perforated screen. A centralized HVAC unit creates negative pressure in the air intake duct such that air is drawn in through each input vent and filtered through each filter media that covers each perforated screen.

The actuation of any of the drive tube covers the perforated screen with a new portion of the length of the filter media from the filter roll. The drive tubes could be actuated manually or with a timer. The drive tubes could be driven by stepper motors, servo motors, or DC motor with a rotary encoder. Pressure sensors could be located inside each input vent for actuating the associated drive tube when the pressure inside the input vent surpasses a preset threshold. A misting system could also be incorporated to spray liquid onto filter media to improve filter performance and optionally to sanitize the air flowing through the system.

Those skilled in the art will realize that this invention is capable of embodiments that are different from those shown and that details of the devices and methods can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and descriptions are to be regarded as including such equivalent embodiments as do not depart from the spirit and scope of this invention.

Brief Description of Drawings

For a more complete understanding and appreciation of this invention, and its many advantages, reference will be made to the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 shows a perspective view of a partially disassembled self-maintaining air filtration device showing the installation of a perforated screen onto the enclosure;

FIG. 2 shows a perspective view of the self-maintaining air filtration device of FIG. 1 showing the filter media being pulled over the perforated screen;

FIG. 3 shows a perspective view of the self-maintaining air filtration device of FIG. 1 showing the filter media installed over the perforated screen;

FIG. 4 shows a perspective view of the self-maintaining air filtration device of FIG. 1 showing the installation of filter media onto the drive tube;

FIG. 5 shows a cut out view of the bottom view the self-maintaining air filtration device showing the air flow through the device with the fans exhausting air out through the vents; FIG. 6 is a side cut out view of the self-maintaining air filtration device of FIG. 5;

FIG. 7 shows a cut out view of the bottom view the self-maintaining air filtration device showing the air flow through the device with the fans pulling air in through the vents;

FIG. 8 is a side cut out view of the self-maintaining air filtration device of FIG. 7;

FIG. 9 shows an embodiment of self-maintaining air filtration device that incorporates a misting system;

FIG. 10 shows a side view of an intake duct installed in rooms of a building illustrating the operation of the self-maintaining air filtration system;

FIG. 11 shows a perspective view of an air intake duct that has a plurality of input vents without the filter media installed over the input vents;

FIG. 12 shows the air intake duct of FIG. 11 showing the installation of the filter media across the input vents; and

FIG. 13 shows the air intake duct of FIG. 11 showing the installation of the filter media to the drive tubes.

Detailed Description

Referring to the drawings, some of the reference numerals are used to designate the same or corresponding parts through several of the embodiments and figures shown and described. Corresponding parts are denoted in different embodiments with the addition of lowercase letters. Variations of corresponding parts in form or function that are depicted in the figures are described. It will be understood that variations in the embodiments can generally be interchanged without deviating from the invention.

As best understood by comparing FIGs. 1 through 4 the self-maintaining air filtration device 10 comprising an enclosure 12 through which air is filtered. The entire air filtration device 10 is made of PVC plastic sheets having overall dimensions of 49.5 inches of length, 22.5 inches of height and 23.5 inches of width. The enclosure comprises at least one open face 14 and at least one air channel 18 through which air is draw into the air filtration device 10. In this embodiment, the enclosure 12 shown has three open faces 14 and two air channels 18. A perforated screen 20 covers each open face of the enclosure 12. A filter roll 22 is mounted on one side of the enclosure 12 on bearings (not shown).

The filer roll 22 comprises a long length of filter media 26 that is rolled onto the filter roll 22. The bearings allow the free rotation of the filer roll 22 that allows for easy dispensing of the filter media 26. The filter roll 22 may be mounted to the enclosure 12 with any other means that allows its free rotation, such as spindles, rods, or other devices. The filter roll 22 is installed on spring-loaded plungers that allow for easy installation and removal of the filter roll 22 from the enclosure 12. The filter media 26 may be any air filter media that is dispensable on filter rolls 22. UNIPRO 150 woven polypropylene fabric has been shown to be an acceptable material, but HEPA filters and other filters may also be used.

A drive tube 28 is mounted to the enclosure 12 on the opposite side from the filter roll 22. The drive tube 28 is installed on spring-loaded plungers that allow for easy installation and removal of the drive tube 28 from the enclosure 12. As shown in FIGs. 2, 3, and 4, a portion of the length of the filter media 26 is pulled from the filter roll 22, over the perforated screen 20, and attached to the drive tube 28 in any manner that allows the filter media 26 to be rolled onto the drive tube 28. The free end of the filter media 26 is coated with an adhesive that adheres to the drive tube 28 but it may be secured to the drive tube 28 by other means such as pins, slots, tacks, etc. The drive tube 28 is mounted to a drive motor 30 on the enclosure 12 that actuates and rotates the drive tube 28 to pull the filter media 28 and unroll it from the filter roll 22. As the drive motor 30 is actuated, a new portion of the length of the filter media 26 from the filter roll 22 is pulled over the perforated screen 20. The drive motor 30 may be a stepper motor, servo motor, a DC motor with a rotary encoder, or any other device that is able to rotate the drive tube 28 and pull the filter media 26 over the enclosure 12.

The perforated screen 20 is what the filter media 26 rests against. It provides support and structure the filter media 26 against the air flowing through the air filtration device 10. This is a critical part of the air filtration device 10 because it determines how much air flows through the system. The size and spacing of the openings determine the amount of air flow, allowing for the most particles possible to be captured on the filter media 26 before it is advanced.

Air current inducers 32 inside the enclosure 12 are used to expel air through the air channels 28, creating negative pressure in the enclosure 12 such that air is drawn into the enclosure 12 and filtered by the filter media 26 that covers the perforated screen 20. The air current inducers 32 shown in the figures are fans 34 mounted to each air channel 18 powered by a fan motor 36 that, in the embodiment shown, is a ¼ horsepower motor, requiring 115 volts. The fans 34 are rated at 1,500 cfm. The size of the fan motors 36 and the fans 34 may be varied as needed. Other devices such as air multipliers, air pumps, or any other device may be used. The end faces of these air channels 18 are protected by metal meshes 38 to prevent access to the fans 34.

These air channels 18 are used to control air flow. As shown in FIGs. 5 and 6, the air channels 18 allow the fans 34 to draw in dust particles evenly from three sides of the air filtration device 10 through the perforated screen 20 and filtered by the filter media 26 that covers the perforated screen 20 and blow clean air out the air channels 18. As shown in FIGs. 7 and 8, the air filtration device 10 could be run in the opposite direction with air being drawing into the air channels 18 through the meshes 38 and expelled from through the perforated screen perforated screen 20 and filtered by the filter media 26 that covers the perforated screen 20. In this mode, the air filtration device 10 could operate as a smoke collector with the only change being that the filter media 26 would be HEPA filters and/or other smoke and particulate filters.

While a control box 16 houses a circuit board with control circuitry that operates the various components of the air filtration device 10, the drive tube 28 may be actuated manually or with a timer. The control box 16 has four main functions: to turn the air filtration device 10 on and off; to run the air current inducers 32; to manually actuate the filter media 26 advancement cycle; and to set the timer for automatic filter media 26 advancement cycles. As the filter media 26 filters the air passing through the air filtration device 10, particle build up on the filter will reduce airflow through it. A pressure sensor 40 may be incorporated inside the enclosure 12 to initiate actuation of the drive tube 28 when the pressure inside the enclosure 12 surpasses a preset threshold. In general, each actuation of the drive tube 28 covers the perforated screen 20 with a new portion of the length of the filter media 26 from the filter roll 22. The timing system to control the drive tube 28 could be mechanical rather than through software controls. A counting tool or clicker could be used to measure the length of filter media 26 as it advances on the drive tube 28 and stop the drive motor 30 when the required length of filter media 26 has crossed over the perforated screen 20. The control box 16 could also incorporate remote controls through handheld portable devices or remote connections to smartphones, computers, or remote HVAC control systems.

The drive motor 30 is set up on a timer: once the pressure sensor 40 activates the drive motor 30, it will begin turning and timing, providing the required length of new filter media 26 over the perforated screen 20 each time. The air current inducers 32 will be shut off at this time to prevent the filter media 26 from catching against the perforated screen 20 and will turn back on when the drive motor 30 has completed its actuation cycle. As the filter media 26 is used up over time, more and more of it will be transferred from the filter roll 22 to the drive tube 28. As the filter media 26 builds up on the drive tube, it creates a larger rotation, meaning it takes fewer rotations for the filter media to advance to the correct length than before. The circuit board in the control box 16 tracks filter media 26 advancement and adjusts the actuation of the drive motor 30 for the correct amount of time to move the required amount of new filter media 26 across the perforated screen 20.

The air filtration device 10 is self-maintaining. This means that when the filter media 26 that is becomes filled with particles, the drive motor 30 will actuate the drive tube 28 to advance the filter media 26 over the perforated screen 20, providing a clean filter media 26 surface in seconds. When the filter roll 22 is exhausted of unused filter media 26, the drive tube 28 with the used filter media 26 and the now empty filter roll 22 are removed from the air filtration device 10 and disposed. A new filter roll 22 with unused filter media 26 and a new drive tube 28 are installed.

The air filtration device 10 has several advantages over the prior art. Over 60% of the surface of the air filtration device 10 is filter media 26 material. Drawing in dust particles from many angles rather than just one. The air filtration device 10 is typically hung from the ceiling completely out of the way. A pulley assembly (not shown) could be built into the ends of the air filtration device 10 to make it easy to raise and lower the air filtration device 10 to a selected height.

It will be understood that variations of the air filtration device 10 are easy to extrapolate from the base design shown. For example, the air filtration device 10 could be built to a smaller scale to be portable. It could also have a single air channel 18 and mounted vertically. This would be idea for small shops to place dust collectors on floors or tables. FIG. 9 shows a variation of the air filtration device 10a that comprises a misting system

42a to periodically sprays liquid 44a onto the filter media 26a. The liquid 44a is stored in reservoirs 46a and the misting timing and quantity would be controlled by the control circuity in the control box 16a. Wetting the surface of the filter media 26a improves its ability to trap dust. The liquid could be antiseptic and could be used to disinfect the air passing through the air filtration device 10a.

FIG. 10 shows how the concept of self-maintaining air filtration systems 10b can also be incorporated into large scale HVAC systems for buildings 54b. In such systems, at least one air intake duct 48b would extend through each room of the building. A plurality of input vents 50b would be distributed along the intake duct(s) 48b as needed. As best shown in FIG. 11, each input vent 50b further comprising a perforated screen 20b that covers the input vent 50b. A filter roll 22b is mounted to one side of each input vent 50b comprising a length of filter media 26b. A drive tube 38b is mounted on the opposite side from the filter roll 22b. As best shown in FIGs. 12 and 13, a portion of the length of the filter media 26b is pulled from the filter roll 22b over the perforated screen 20b and attached to the drive tube 28b in any manner that allows the filter media 26a to be rolled onto the drive tube 28a. The free end of the filter media 26a is coated with an adhesive that adheres to the drive tube 28a but it may be secured to the drive tube 28a by other means such as pins, slots, tacks, etc. The drive tube 28a is mounted to a drive motor 30a on the input vent 50b that actuates and rotates the drive tube 28a to pull the filter media 26a and unroll it from the filter roll 22a. As the drive motor 30a is actuated, a new portion of the length of the filter media 26a from the filter roll 22a is pulled over the perforated screen 20a. The drive motor 30a may be a stepper motor, servo motor, a DC motor with a rotary encoder, or any other device that is able to rotate the drive tube 28a and pull the filter media

28a over the input vent 50b. The intake ducts 48b are connected to centralized HVAC unit (not shown) that creates negative pressure in the air intake duct 48b such that air is drawn in through each input vent 50b and filtered through each filter media 26b that covers each perforated screen 20b. Each input vent 50b could have individual control boxes with control circuity to control the actuation of drive motor 30b in any manner described with earlier embodiments or all the components could be controlled by a centralized control system that controls each component as needed. Any of the variations discussed above could be applied to each input vent 50b.

This invention has been described with reference to several preferred embodiments. Many modifications and alterations will occur to others upon reading and understanding the preceding specification. It is intended that the invention be construed as including all such alterations and modifications in so far as they come within the scope of the appended claims or the equivalents of these claims.