Patent Publication Number: US-2022220682-A1

Title: Dry filtration system

Description:
In accordance with 37 C.F.R. 1.76, a claim of priority is included in an Application Data Sheet filed concurrently herewith. Accordingly, the present invention claims priority to U.S. Provisional Patent Application No. 62/154,079, entitled “DRY FILTRATION SYSTEM”, filed Feb. 26, 2021. The contents of the above referenced application is incorporated herein by reference in its entirety. 
    
    
     FIELD OF INVENTION 
     The present invention relates to debris removal and, more particularly, to a dry filtration system for removal of airborne particulate matter. 
     BACKGROUND INFORMATION 
     Road surface maintenance includes the removal and replacement of guidance markings. Thermoplastic material has become one of the most common types of guidance markings based on its balance between cost and performance longevity. Thermoplastic is durable, easy to apply, and can be used for markings such as yellow caution lines, white edge lines, turn signal lines, reflective markers, and so forth. When the markings need to be replaced, a common method is the use of a grinder vehicle that quickly removes the marking in preparation of a replacement marking. 
     Another type of surface preparation consists of rumble strips, which are a series of troughs ground into the asphalt roadway. Rumble strips can be used to warn of hazards of not staying within a specific lane, and can create a strong vibration and sound to alert vehicle drivers. 
     When surface markings are to be replaced, rumble strips ground, or the like maintenance, the use of a vehicle having a grinder head can be employed. A grinder head is capable of deep impact cuts into the road surface to form rumble or grooving strips, or for use in minimal surface impact for removal of thermoplastic markings without damaging the road surface. 
     The removal of surface markings and asphalt will result in the creation of fine airborne particulates. The particulates, including airborne silica dust, can be hazardous to the equipment operators, as well as the equipment. 
     Dry filtration techniques are known in the industry, consisting of filtering dust out of the air and then cleaning the filters in the dry filtration process. A conventional method for inline cleaning consist of a short pulse of air from a tank of compressed air, which does very little to actively restore air flow. A minimal amount of particles will pop off the surface, but then quickly return to almost the same location when normal air flow resumes. This method does not provide enough time for dust to fall out. 
     What is needed in the art is an improved dry filtration system that allows for efficient removal of airborne particulates and continuous cleaning of the filters. 
     SUMMARY OF THE INVENTION 
     Disclosed is a mobile vehicle mounted dry filtration system for removal of dust and debris. The system is in support of a grinder system used for removal of markings or creating rumble strips. Rotary lobe blowers powered by hydraulic motors used to create a vacuum for drawing debris and dust from the grinder system into a debris bin. Large debris is removed from the vacuum draw and remains in the bin for later disposal. Small particles and dust are drawn into parallel positioned filter cyclones having cyclonic separation followed by flexible bag filters. The flexible filters are cleaned using vibrating diaphragms mounted on the top of the filter cyclones, subject to a reverse air flow by the blowers using slide valves. A polishing tank containing water receives the exhaust from the filter cyclones for removal of airborne particles and sound suppression. 
     An objective of the invention is to provide a dry filtration system using sonic vibration for on-line continuous cleaning of inexpensive bag filters. 
     Another objective of the invention is to provide a dry filtration system for use in reduction of airborne silica. 
     Still another objective of the invention is to provide a system for off loading captured debris into an adjoining dump truck. 
     Still another objective of the invention is to provide a sonic vibration system using slide valves to allow instant and momentary high volume reverse air flow for cleaning of bag filters. 
     Still another objective of the invention is to teach the use of filter cyclones having a dust box and a debris bin which can be raised using a scissors jack, allowing the dust and debris to be placed into a dump truck. 
     Still another objective of the invention is to reduce the airborne dust while dumping by use of atomizing water with the correct charge, positive or negative, through nozzles arranged around the opening of the dust box or debris tank. 
     Yet still another objective of the invention is to teach the use of filter cyclones having a dust box adjoining a debris tank that can be lifted together, but doors opened independently to manage dust and debris disposal. 
     Yet still another objective of the invention is to provide a reduction of noise through a water polishing chamber. All exhaust air is pumped through water; water absorbs sound energy and collects dust particles as efficiently as a HEPA filter. Water is drained regularly and clean water is added. 
     Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification, include exemplary embodiments of the present invention, and illustrate various objects and features thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of a mobile vehicle with the dry filtration system of the instant invention mounted thereto. 
         FIG. 2  is a side view thereof; 
         FIG. 3  is a top view thereof; 
         FIG. 4  is a perspective view of the debris bin and filter cyclones; 
         FIG. 5  is a perspective view of the filter cyclones with open lids; 
         FIG. 6  is a cross-sectional view of a filter cyclone; 
         FIG. 7  is a plane view of a 3-way, 2-position slider in a normal position; 
         FIG. 8  is a plane view of the 3-way, 2-position slider in a reverse air position; 
         FIG. 9  is a side view thereof; 
         FIG. 10  is a plane view of a 3-way, 3-position slider in a normal position; 
         FIG. 11  is a plane view of the 3-way, 3-position slider in position to clean one filter cyclone; 
         FIG. 12  is a side view thereof; 
         FIG. 13  is a plane view of the 3-way, 3-position slider in position to clean a second filter cyclone; 
         FIG. 14  is a perspective view of a finishing chamber; and 
         FIG. 15  is a cross-sectional view thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred and alternative embodiments with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     Referring to Figures, illustrated is the mobile vehicle  10  of the instant invention. The vehicle includes an operator&#39;s station  12  with a chassis  14  for support of a grinder system. The grinder system has controllable grinders  16  and  18  used for removal of markings or creating rumble strips, resulting in the creation of debris and the associated dust. Rotary lobe high vacuum blowers  20  powered by a hydraulic motor are used in creating a vacuum for drawing debris and dust into a debris bin  50 . Large debris is removed from the vacuum draw and remains in the bin  50  for later disposal. When the debris is to be dumped, airborne dust is removed by use of atomizing water with the correct charge, positive or negative, through nozzles arranged around the opening of the dust box or debris tank. With the debris held in the bin  50 , small particles and dust are drawn into parallel positioned filter cyclones  100  and  102 . The filter cyclones, explained later in this specification, capture small particles through a cyclonic separation and the dust is removed by bag filters  130 . The bag filters  130  are cleaned using vibrating diaphragms  124  mounted on the top of the filter cyclones  100  and  102  and a reverse air flow provided by the blowers using a 3-way, 2-position slide valve  150  and a 3-way, 3-position slide valve  170 . A polishing tank  200  is half full of water and receives the exhaust from the filter cyclones for removal of airborne particles and sound suppression. 
     Referring to Figures, debris created by the grinders  16 ,  18  is first drawn through the debris bin  50 ; the debris bin  50  having sufficient volume to allow debris to separate from the flow caused by the blowers and remain in the bin  50  for subsequent disposal. When the debris bin  50  is to be emptied, a chute  52  is rotated into an open position along hinges  54 ,  56  as illustrated. A side door  58  of the bin  50  can be opened upwardly using a hinged upper edge by operation of the hydraulic rams  62 ,  64 , which rotates a lower edge  66  of the door  58  into a raised position. During a bin emptying cycle, a platform  70  holding the debris bin  50  and filter cyclones  100 ,  102  can be raised by a jack mechanism  72  to place the platform  70  above an edge of an adjoining dump truck, not shown. The platform  70  can further be tilted in the raised position, wherein the debris held in the bin  50  can easily be transferred to the adjoining dump truck. Similarly, as will be further explained herein, a dust door  104  can be raised by a hydraulic ram  106  to expel collected dust from a collection box positioned beneath the filer cyclones  100 ,  102 . The debris bin side door  58  and the dust door  104  open independently, wherein dust can be expelled first into a dump truck followed by the debris. In this manner, the dust is less likely to be lost during transit by the dump truck, as the debris operates as a cover for the dust. 
     The filter cyclones  100 ,  102  are both pressure and vacuum rated. The tanks are placed in parallel for handling a typically work environment. Smaller volumes may use a single tank; larger volumes may use additional tanks. For ease of explanation, a single filter cyclone  100  will be described. The filter cyclone tank  100  includes a hinged lid  110  having an outer edge  112  that is secured to an upper edge  114  by a plurality of clamps  116 . An inner circumference  120  of the hinged lid  110  employs a suspension material consisting of a fiber embedded rubber sheet for supporting a diaphragm  122  and a centrally disposed vibrator  124 . Positioned within the tank  100  is a plurality of filter bags  130  providing about 500 sq ft surface area coverage. The filter bags  130  are placed in a housing  132  that is spaced apart from the inner surface  134  of the tank to allow a cyclonic air flow therebetween. The vibrator  124  is used to drive the diaphragm  122  up and down to produce both positive and negative pressure waves in the clean air stream that&#39;s inside the filter bags  130 . The positive and negative pressure waves cause the filter bags walls to pulsate inward and outward, which dislodges the dust particles from the filter bags  130 . The dislodged dust particles drop into the dust collection box  108  positioned beneath the filter bags  130 . In combination with the vibrator  124 , high volume clean air is introduced to the filter cyclones  100 ,  102 , as will be explained further in this specification. 
     The unfiltered dusty air is drawn from the debris bin through unfiltered inlets  140 . The dusty air is drawn between the filter housing  132  and the inner surface  134  of the tank wall  100 , forming the cyclonic air flow which is capable of separating heavier dust from the remaining dust material which is drawn through the filters  130 . Clean air that is drawn through the filters  130  is pulled through the filter outlets  142  positioned along the upper edge  114  of the tanks. A second set of inlets  144  positioned adjacent to the filter outlets  142  allow a high volume of clean air to be reversed into the filters  130  to supplement the sonic vibration produced by the vibrating diaphragms  124  and their diaphragms  122  for the purpose of dislodging dust from the filter bags  130 . 
     The high volume of clean air is provided by the use of slide valves. This is contrary to the conventional method of cleaning a filter by a short blast of compressed air. Referring to  FIGS. 7-9 , illustrated is a high speed 3-way 2-position slide valve  150  that is controlled by a PLC to perform cleaning functions as the operator selects. The slide valve  150  is formed from a base  152  and sliding plate  154  that is moved by actuators  156  and  158 . A slide ring seal  163  is positioned between the base  152  and the sliding plate  154 . In  FIG. 7 , the slide valve  150  is illustrated in the normal position with a first aperture  160  fluidly coupled to the vacuum side tube of a blower  20  and a second aperture  162  fluidly coupled to the compressed air side of the blower  20 . In this position, air is being vacuumed from the filter cyclone  100  and directed to a polishing filter  200 . As illustrated in  FIG. 9 , the slide valve  150  is in a reverse air flow position wherein the vacuum hose  162  of the cyclone filter is moved to the clean compressed air side of the blower, allowing a high volume of compressed air to flow back to the cyclone filter to supplement cleaning of the filters with the vibrating diaphragms. The hose coupled to the compressed side  162  is moved to a position open to the atmosphere, which discontinues air flow to the polishing chamber  200 . The lower aperture  164  is on the vacuum side, providing clean ambient air to the blower. The slide position is moved by the actuators  156 ,  158 . 
       FIGS. 10-13  illustrate the 3-way, 3-position splitter high speed slide valve  170 .  FIG. 10  illustrates the valve  170  in the normal position, which is the non-cleaning mode. The slide valve  170  has a base  172  and slide plate  174  using 3-position actuators  176  and  178 . In this figure, the actuators  176  and  178  are placed in a partially extended position with the vacuum air hose to the first cyclone tank attached to an upper aperture  180  and the vacuum air hose to the second cyclone tank attached to the lower aperture  182 . The vacuum inlet  184  is drawing air from both the first and second cyclone tank  100 ,  102 . Referring to  FIGS. 11 and 12 , the slide valve  170  is shown in a position for cleaning the second cyclone, wherein 3-position actuators  176 ,  178  are placed in a retracted position with the first filter cyclone inlet  182  receiving full vacuum air flow from the blower inlet  184 , while the second cyclone tank is being cleaned. The second filter cyclone aperture  182  is shut off because it is under pressure while it is being cleaned. 
       FIG. 13  depicts the slide valve  170  in a position for cleaning the first filter cyclone. A slide ring seal  185  is positioned between the base  172  and the sliding plate  174 . In this illustration, 3-position actuators  176  and  178  are placed in an extended position with the second filter cyclone receiving full vacuum air flow from the blower aperture  180 , while the first cyclone tank is being cleaned. The aperture for the first filter cyclone is shut off because it is under pressure while it is being cleaned. 
     Referring to  FIGS. 14 and 15 , the polishing chamber  200  is used to reduce the dust and noise for the dry filtration process. The polishing chamber consists of a substantially rectangular tank  202  that is half filled with water  205 . Exhaust air is received through inlets  204 ,  206  from the debris bin  50  while the filters  130  are in use. Exhaust air enters the polishing tank  200  through the inlets  204 ,  206  and is directed through piping  208 ,  210  having outlets  212 ,  214  immersed in the water  205 . A lower perforated plate  218  and an upper perforated plate  220  are constructed and arranged to control aeration, mixology and splash with the exhaust air expelled into the water. The water  205  absorbs sound energy in a manner similar to outboard motor exhaust placement used in the marine industry. The water collects dust particles, providing particle efficiency in removal. The water is drained regularly through a drain connection  222  and clean water is added through a fill valve  224 . The exhaust exits a flap lid  226  on the top  228  of the tank  202 . The exhaust at this stage is substantially free of particles, and the noise level greatly reduced as the water operates as a muffler. Exhaust air is directed through inlets  230 ,  232  while the filters are being used, exhaust air is directed through inlets when filters are being cleaned. 
     All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. 
     It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification. 
     The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically. The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more” or “at least one.” The term “about” means, in general, the stated value plus or minus 5%. The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternative are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” 
     The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises,” “has,” “includes” or “contains” one or more steps or elements, possesses those one or more steps or elements, but is not limited to possessing only those one or more elements. Likewise, a step of a method or an element of a device that “comprises,” “has,” “includes” or “contains” one or more features, possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed. 
     One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Any compounds, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary, and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.