Patent Publication Number: US-2003228839-A1

Title: Vacuum conduit system for removal of fumes and air borne particulate matter

Description:
FIELD OF THE INVENTION  
       [0001] This invention relates to the field of vacuum systems and in particular to an airborne particulate removal apparatus having a main flexible conduit in fluid communication with a plurality of flexible secondary conduits rotatably mounted to the primary conduit.  
       BACKGROUND OF THE INVENTION  
       [0002] As stated by Parker in U.S. Pat. No. 5,160,292 which issued Nov. 3, 1992 for A Vacuum System for Multiple Work Areas, many industries use equipment which in operation generates atmospheric contaminants, which might be gases or airborne particles. These gases and particles are sometimes a health hazard to the operator, as well as to other employees and the environment in general. This problem is especially acute in industrial operations such as wood-working or painting, where dust and gases that are harmful if inhaled are generated in close proximity to the worker. Additionally, particulates can eventually build up and damage equipment in the work area, and often require regular cleaning of the work area. Government regulations in many instances now strictly regulate the amount of such gases and particles which can be present in or emitted from the work area.  
       [0003] Vacuum systems have been installed to withdraw airborne contaminants generated in such work areas. A single vacuum source is usually provided. A manifold usually communicates between the vacuum source and a number of vacuum conduits, the conduits extending to individual work areas. Vacuum openings in the vacuum conduits are provided at the work areas to permit the withdrawal of air from the work area. The gases and particles in the air are thereby removed, and subsequent filtration or other cleansing operations can be employed downstream to permit subsequent disposal of the contaminants. A hood can be provided in association with each vacuum conduit and vacuum opening to reduce the amount of particles and gases that escape from the work area.  
       [0004] As disclosed in U.S. Pat. No. 6,322,618 which issued Nov. 27, 2001 to Simms et al. for An Adjustable Duct Assembly for Fume and Dust Removal and Filter Cleaner, an adjustable duct assembly for the collection of fumes, dust and the like may include two duct sections connected end-to-end by a duct support system which includes two elongate arms pivotally connected, the arms attached to the adjacent ends of the ducts. Similarly, applicant is aware of U.S. Pat. No. 5,482,505 which issued Jan. 9, 1996 to Hedlund for An Arrangement for Extraction of Harmful Gases from Workplaces in which is disclosed a carrier arm having two arms connected telescopically with each other where the carrier is swivel mounted so that it can be swivelled in a vertical direction between a downward-directed position and an outward-directed for example horizontal position. Similarly also, applicant is aware of U.S. Pat. No. 5,738,148 which issued Apr. 14, 1998 to Coral et al. for a Universal Connector Hose for Joining an Extractor to an Element for Extracting Fumes from a Factory Workplace in which is disclosed a hose having two flexible portions connected respectively to the suction unit and to the fume-conveyor element or hood and a rectilinear portion which is articulated to the suction unit and the hood. Other articulated fume extraction arms of which applicant is aware are described in the following U.S. Pat. Nos.: 4,540,202; 5,427,569; 5,527,217; 5,536,206; 4,860,644; and 5,336,130.  
       [0005] What is neither taught nor suggested in the prior art, and what is one of the objects of the present invention to provide, is a constant diameter modular ducting having a cable suspension system and which is, when compared to the prior art, easy to erect, and which may be a low static compressed air driven fan system providing multiplexing capabilities of, for example, five hose airstreams to one primary hub having a single low pressure source such as a central exhaust fan. The flex hose design of the present invention provides suction outlets which may optimize fume extraction with minimal repositioning and which, at the other end of the flex hoses, are provided with hose-to-main duct fittings which minimize static pressure drop and equalize flow in multiple flex hose arms.  
       SUMMARY OF THE INVENTION  
       [0006] In one embodiment of the present invention, a main or primary flexible duct has alternating flexible sections and rigid sections, providing a duct of substantially constant sixteen inch diameter. Prefabricated hose connection pieces provide for rapid assembly using releasable hose clamps to modularly secure the modular sections of the primary ducting to each other. Advantageously, the primary duct is tubular. The ducting provides maximum versatility in conforming to a round, square or rectangular work space or may be extended in a straight line. Equal exhaust flow from each of a plurality of flexible secondary hoses, that is, the hose arms or legs, which may be four inch diameter hoses, branching from the primary duct is promoted by static pressure optimization of the flow from the secondary hoses through flow optimizing fittings, which may in a preferred embodiment be diffuser fittings having a four to six inch diameter feeding into a sixteen inch primary duct, where the diffuser fittings incline the flow from the secondary hoses in the direction of flow through the primary ducting.  
       [0007] A fan housing has external loops, which permit a cable attachment to the nearby first wall of a building. At the opposite end of the run of primary ducting, an end cap has a bar, which extends outwardly of the cap to allow a cable yoke to be attached. A tensioning/supporting cable is attached to the yoke, passes around pulleys attached to the opposite second end of the building and returns to an anchoring point at the first wall. A tensioning device is provided near the second wall for applying or relieving tension on the tensioning/supporting cable.  
       [0008] The flex sections of the primary ducting are connected to the rigid sections (so-called hard bodied sections) by flexible couplers secured by a pair of annular clamps. One end of the flexible coupler is mounted to the hard body section by a clamp having double annular bead receiving grooves or channels each tensionable by its own latch. By partially releasing one of the latches, for example the latch adjacent to the hard body section, the flexible section is still held securely by the flexible coupler, but the hard body section may be rotated about its longitudinal axis relative to the flexible coupler and then re-clamped into its desired orientation.  
       [0009] A frusto-conical diff-user is mounted to the inclined base of the diffuser fitting and secured by a double bead receiving clamp. The inclined base is mounted over an aperture in the hard body section. A section of secondary hose is mounted to the diffuser by another flexible coupler. A vacuum head may be secured at the anterior end of the secondary hose by a connector such as another flexible connector or coupler.  
       [0010] The removable thirty degree base of the diffuser fitting has a rigid base flange having a resilient under-gasket in contact with the hard body section. It is secured to the hard body section by a clamp passing around the hard body section. Upstream of the aperture in the hard body section is a locking member while downstream is an upstanding gusset, which is aligned with a corresponding slot in base flange of the fitting. The gusset has an aperture, which will accept a clip to retain the fitting snugly in place. The gusset prohibits rotation of the fitting on the hard body section during closure of retaining clamp. The retaining clip also has a ground wire to eliminate static electricity build-up.  
       [0011] The helically wrapped wire in the large diameter flex hose of the flexible section of the primary ducting is exposed near the hard body section. Static electricity build up may be eliminated by bringing the wire in contact with the clamp on the hard body section or by clipping a ground wire to it.  
       [0012] A length of flexible cable joins each hard body section, and is connected between rigid connection bars secured to the inner surface near each of the ends. The cables prohibit over-extension of each flexible section along the vacuum manifold provided by the primary ducting.  
       [0013] For use in localized general ventilation and localized exhaust ventilation, the vacuum conduit system for removal of fumes and air borne particulate matter according to the present invention may be summarized as including a primary duct and a plurality of flexible secondary ducts mounted in fluid cooperation to the primary duct. The primary duct includes hollow rigid conduit sections interspersed between, and in fluid communication with, hollow flexible conduit sections. An upstream end of the primary duct is sealed substantially air-tight. An opposite downstream end of the primary duct cooperates with an air extraction means for extracting air from the primary duct so that the primary duct functions as a vacuum manifold. Secondary ducts may be mounted at their downstream ends to the rigid conduit sections and inclined at an inclined angle relative to the rigid conduit sections so that secondary airflows leaving the downstream ends of the secondary ducts are inclined into an airflow stream in the primary duct so as to be directed in a downstream direction of the airflow stream in the primary duct. It is an object to generally equalize vacuum levels at the downstream ends of the secondary ducts.  
       [0014] The secondary ducts may be short fittings or just localized capture apertures for localized general ventilation, or may include long flexible hoses for localized exhaust ventilation. The primary duct has a constant first diameter and the secondary duct has a second diameter. The first and second diameters preferably form a ratio of greater than two. The ratio may be 16:6 or 16:4, or may be in the range of 16:4 to 16:6. The inclined angle may be substantially thirty degrees.  
       [0015] The rigid section may be cylindrical and the secondary duct may be mounted thereto by means of a generally cylindrical diffuser fitting inclined at the inclined angle in the downstream direction of the airflow stream in the primary duct. The diffuser fitting has a downstream aperture and the rigid section has an aperture in a wall thereof, so that the downstream aperture of the diffuser fitting mates and seals over the aperture in the wall of the rigid section. The diffuser fitting may include a conical frustum mounted at a narrow end thereof to the downstream end of the secondary duct. A cylindrical section of the fitting is mounted to the wider opposite end of the conical frustum. The aperture in the wall of the rigid section may be pyriform so as to have a narrower end and an opposite broader end, wherein the narrower end is upstream of the broader end along the airflow stream in the primary duct. The rigid section may include a rotatable section selectively rotatably mounted by cuff mounting means between adjacent flexible sections so as to be selectively rotatable about a longitudinal axis of the airflow stream in the primary duct. Selectively releasable locking means may be provided for locking the rotatable section on the cuff mounting means relative to the flexible sections in an angular position so as to generally direct a corresponding secondary duct of the plurality of secondary ducts to a desired workspace.  
       [0016] The primary duct may include sections of flexible tube as the flexible conduit sections. Each secondary duct of the plurality of secondary ducts may be a flexible hose. A vacuum head may be mounted at the upstream-most end of each of the secondary ducts. A cable suspension means may be provided for suspending the primary duct under a cable of the cable suspension means, wherein the cable is mountable, and releasably tensionable by tensioning means, between rigid supporting surfaces. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0017]FIG. 1 is, in side elevation view, the vacuum conduit system of the present invention in an embodiment suspended from a cable.  
     [0018]FIG. 2 is, in partially exploded partially cut away perspective view, a hard body section of the vacuum conduit system according to one embodiment of the present invention.  
     [0019]FIG. 2 a  is, in partially cut away partially exploded view, the mounting of the secondary conduit fitting onto the primary conduit hard body section of FIG. 2.  
     [0020]FIG. 3 is, in exploded perspective view, the upstream-most end of the primary duct of the vacuum conduit system according to one embodiment of the present invention.  
     [0021]FIG. 4 is, partially cut away plan view, a vacuum head on a secondary duct of a vacuum conduit system according to one embodiment of the present invention.  
     [0022]FIG. 4 a  is, in front elevation view, an alternative embodiment of the vacuum head of FIG. 4.  
     [0023]FIG. 5 is, in perspective view, the hard body section of FIG. 2 with the secondary conduit fitting removed.  
     [0024]FIG. 6 is, in partially exploded perspective view, the vacuum head and flexible secondary duct of FIG. 4.  
     [0025]FIG. 7 is, in perspective view, an alternative embodiment fitting for mounting the flexible ducting according to the present invention onto existing rigid fixtures.  
     [0026]FIG. 7 a  is, in partially cut away elevation view, the mounting fixture of FIG. 7. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION  
     [0027] As seen in FIG. 1, the ducting system of the present invention includes a primary duct  10  which is modularly constructed of flexible sections  12  of sixteen inch diameter flexible hose, tube or conduit interspersed between hollow rigid sections  14  seen in better detail in FIGS. 2, 2 a  and  2   b.    
     [0028] In the preferred embodiment, both flexible sections  12  and rigid sections  14  are substantially tubular so that, as better describe below, fittings  16  may be rotated about the longitudinal axes A of the rigid sections  14  to which they are releasably mounted.  
     [0029] Fittings  16  mount flexible secondary hoses  18  to the rigid sections  14  so as to dispose the longitudinal axes of symmetry B of fittings  16  to intersect longitudinal axis A to form an included angle α of substantially thirty degrees. Each secondary hose  18  may be in the order of twenty to twenty-five feet long and may have mounted at its distal or upstream end a vacuum head  20  as better seen in FIGS. 4 and 6 and described below.  
     [0030] Primary duct  10  may be suspended, for example, between two walls  22  by a cable  24  tensioned between anchors  26  mounted to walls  22 . Cable  24  extends around pulley blocks  27  and is tensioned, releasably, by ratchet hoist  28 . Suspension cables  30  may be mounted in spaced apart array along cable  24 , each of suspension cables  30  mounted at one end to cable  24  and at their opposite ends to, for example, either end of adjacent rigid sections  14  so as to suspend primary duct  10  along the horizontal length of cable  24  extending, for example, parallel to cable  24 .  
     [0031] The upstream-most end of primary duct  10  may be sealed off for example by means of an end cap  32  as better seen in FIG. 3. Cap  32  may be mounted either to a flexible section  12  or a rigid section  14 . A cable yoke  34  may be mounted to a bar  35  on end cap  32  so as to provide for releasably mounting end cap  32  onto one end of cable  24 . A double-bead receiving hose clamp  36  may be used to mount to a single annular bead on end cap  32  and to one of a pair of parallel annular beads on flexible coupler  37 . A single-bead receiving hose clamp  36 ′ mates onto the other annular bead on flexible coupler  37  so as to clamp thereon one end of, for example, a shorter first section  12 ′ of flexible sections  12 . The annular bead-receiving grooves on the hose clamp mate with the corresponding beads on the ends of the flexible couplers or rigid sections of duct.  
     [0032] Adjacent lengths of flexible sections  12  extending between adjacent rigid sections  14  may be of longer lengths. For example, adjacent longer sections  12  may be approximately twenty feet long as primary duct  10  spans the horizontal distance along cable  24 . Thus in the illustrated embodiment, a single primary duct  10  has five rigid sections  14  supporting therefrom five corresponding secondary hoses  18  and sandwiching interposed therebetween four longer flexible sections  12 . Extending downstream from the downstream-most rigid section  14  is a shorter section  12 ″ of flexible sections  12 . A compressed air fan  38 , for example a 5100 CFM capacity fan may be mounted to the downstream-most end of shorter flexible section  12 ″ so as to draw a flow of, for example, particulate laden air in through vacuum heads  20 , and through the corresponding secondary hoses  18  and fittings  16  so as to be drawn into and along primary duct  10  in direction C, wherein each of the secondary hoses may account for approximately 300 CFM.  
     [0033] The downstream ends of each secondary hose  18  is mounted by means of a single-bead receiving hose clamp  40  onto one of a pair of parallel beads on flexible couple  41 . One bead-receiving groove on a double-bead receiving hose clamp  40 ′ clamps onto the other bead on flexible coupler  41 . The remaining bead-receiving groove on hose clamp  40 ′ mounts to the narrower end of a frusto-conical diffuser fitting section  16   a . The downstream end of coupler  41  may fit into the upstream end of section  16   a  is an overlapping fit to streamline flow. Diffuser fitting section  16   a  diffuses the flow leaving secondary hose  18  in direction D into a wider diameter cylindrical fitting section  16   b  which may have an inside diameter of six and one quarter inches. Section  16   a  may be mounted to section  16   b  by double-bead receiving hose clamp  40 ″. As better seen in FIG. 5, the downstream end of fitting  16  mates onto an elliptical or egg-shaped or pear-shaped (collectively referred to herein as pyriform) aperture  42  formed in the wall of rigid section  14  so as to align the long axis of aperture  42  parallel to longitudinal axis A. Fitting  16  has a circumferential flange  16   c  mounted around or formed on section  16   b  so as to extend from the downstream-most end of fitting section  16   b . Flange  16   c  is shaped so as to conformally snugly mate onto the rim  14   a  surrounding aperture  42  so as to sandwich a resilient gasket  17  therebetween. Flange  16   c  has a tongue  44  extending along rigid section  14  in the upstream direction of rigid section  14  when fitting  16  is mounted over aperture  42  so as to mate tongue  44  under curved locking member  46  mounted adjacent aperture  42  to the wall of rigid section  14 .  
     [0034] With tongue  44  releasably inserted between locking member  46  and the wall of rigid section  14 , the opposite end of flange  16   c  may be releasably locked by locking a means so as to flush mount flange  16   c  against and around circumferential edge  14   a . The locking means may for example be an upstanding gusset  48  on section  14  which aligns with a corresponding slot in flange  16   c . The gusset has a hole in it sized to accept a clip. With the gusset slid through the slot so as to expose the hole, a clip may be used to lock the fitting into place. A releasable retaining band  49  secures the sides of flange  16   c  down onto rigid section  14 . A ground wire  48   a  on clip  48  is used to ground static electricity build-up. The helically wrapped wire in the large diameter flex hose is exposed near the hard body. Static electricity build up may be eliminated by bringing the wire in contact with the clamp on the hard body or by clipping a ground wire to it.  
     [0035] As seen in FIG. 2, a clevis mounting member  50  is mounted across each end of a rigid section  14  so as to position a mounting aperture  52  centered along each member  50  on longitudinal axis A. Cables  56  extend between adjacent rigid sections  14  to prevent over-extension of flexible sections  12  when ducting  10  is tensioned. The cable is mounted to rigid sections  14  by swivelling clevis&#39;s  54 . Clevis&#39;s  54  are looped through looped ends of the cable and bolted to apertures  52 . The tension of cables  56  is adjusted to substantially remove the accordion corrugations in the flexible sections so as to reduce static pressure losses.  
     [0036] Double-bead receiving hose clamps  58  releasably secure the ends of flexible couplers  13  onto the ends of rigid sections  14 . In particular, first bead receiving grooves  58   a  mate onto beads  14   a  and are tensioned thereon by latches  58   b . Second bead receiving grooves  58   c  mate onto beads  13   a  and are tensioned thereon by latches  58   d . Single-bead receiving clamps  59  mate onto beads  13   b  to clamp the end of flexible sections  12  thereon. By partially releasing one of the clamps, latches  58   b  or  58   d  to release tension on, for example, the clamping of grooves  58   a  onto beads  14   a  on the hard body sections, the ducting flexible sections  12  may still held securely but the hard body sections may be rotated about their longitudinal axes in direction E to provide for convenient orienting of fittings  16  and hoses  18 .  
     [0037] Similarly, as seen in FIG. 6, annular hose clamps  60  and  60 ′ releasably mount, respectively, the rigid collar  20   a  of vacuum head  20  to one end of flexible coupler  61  and the other end of the flexible coupler to the upstream end of secondary hoses  18 . A truncated-wedge shaped conduit  20   b  forms a venturi entryway into collar  20   a  from the upstream rectangular intake  20   c . A magnet  63  may be mounted adjacent head  20  for releasable mounting the head to metal fixtures As seen in FIG. 4, a handle  62  which may be flexible, for example of rope, may be mounted to vacuum head  20  to provide for ease of positioning of the vacuum head on the distal upstream-most edge of flexible hoses  18 .  
     [0038] As seen in FIGS. 7 and 7 a , a pair of clamps  58  may be welded to a bar. A further clamp  65  is mounted to the bar opposite clamps  58 . This arrangement provides for mounting a flexible section or hard body section to a structural component of a building.  
     [0039] As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention pi without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.