Abstract:
The vent structure comprises a durable material wherein a tortious pathway is provided for gas to flow into and out of a storage tank. The tortious pathway is defined by a plurality of baffles that depend or extend from the inner surface of the vent structure. Further protection of the storage tank contents is provided by employing mesh screen covers over the openings to the vent structure and to the storage tank. Unauthorized disassembly of the vent structure is assisted by using support columns that extend from the cover to the bottom of the vent structure. A terminal portion of each support column may be adapted to pass through a portion of the vent structure and receive a lock. Thereby, an intruder resistant vent structure deters unauthorized access to a storage tank which is particularly useful for protecting a water storage tank.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The present invention relates to vents for water-storage tanks. More particularly, the invention relates to an intruder resistant vent structure for application onto water storage tanks.  
         [0003]     2. Description of Related Art  
         [0004]     Storage tanks are often provided with a vent to allow the gas pressure within the tank to equalize to the ambient atmospheric pressure. Particular to water storage tanks for drinking water, it is desirable to prevent any unwanted matter or persons from gaining entry into the storage tank through the vent opening in the storage tank. When water storage tank vents are not properly protected or their protection device fails, insects, birds, other small animals, and trash may gain entry into the drinking water within the storage tank creating a potential health hazard. To prevent this, vent covers are employed over the vent openings.  
         [0005]     Common vent covers employed with water storage tanks are known to have an enlarged upper cover having a gradually sloping top to drain water away from entry into the tank. This allows air to enter into and from the storage tank vent opening. A mesh screen is often attached with support elements around the vent cover&#39;s opening to prevent the entry of insects into the tank interior. The difficulty with this type of vent cover is that the screens and other components of prior art vent covers are known to fail due to the corrosive environment often found within water storage tanks. Also, animals such as birds or rodents may be able to penetrate screen coverings, especially those that have been weakened due to corrosion. When screen coverings are compromised, unwanted intruders gain access into the interior of the water storage tank.  
         [0006]     Another serious concern with protecting drinking water is from the threat of terrorism. Few prior art vent covers, if any, provide little protection from determined individuals wishing to gain access to the interior of a water storage tank. Therefore, a vent cover that can provide protection from all types of unwanted intruders, including people, is desired Further, the desired vent cover should be designed to include a multiplicity of deterrents to protect the contents of a storage tank.  
       SUMMARY OF THE INVENTION  
       [0007]     A vent structure according to the present invention deters unauthorized access to a storage tank preferably for water. With water storage tanks, a vent is provided so that atmosphere within the storage tank can communicate with the ambient atmosphere surrounding the storage tank to substantially prevent gas in the void volume of the tank from being compressed or expanded. However, providing a vent to the water storage tank also provides an access point into the tank for unwanted intruders. With the vent structure described herein, the vent opening into a storage tank can be protected.  
         [0008]     The vent structure is formed with a bottom plate having a centrally disposed tank opening for attachment to a vent of a storage tank. In a preferred arrangement, a flange may first be affixed to a protruding vent of the storage tank to which the bottom plate may then be attached to the flange. The tank opening allows gaseous flow between an atmosphere in the water storage tank and an atmosphere within the vent structure when connected to the water storage tank. A cover is then affixed above and to the bottom plate to form the vent structure housing. A vent opening formed through the bottom plate allows gaseous flow between the atmosphere of the vent structure and the ambient atmosphere surrounding the water storage tank. A tortuous pathway is disposed within the vent structure between the vent opening and the tank opening to allow gaseous communication between the water storage tank atmosphere and the ambient atmosphere surrounding the storage tank. Further, the tortuous pathway is formed with a plurality of baffles having at least one baffle that extends upward from the bottom plate toward the cover and at least one baffle that depends downward from the cover toward the bottom plate. As additional protection, a mesh screen covering may be affixed to the openings to the tank and to the vent structure.  
         [0009]     To provide further support, the vent structure may include one or more support columns positioned within the vent structure between the vent opening and the tank opening. Each support column extends between the cover and the bottom plate. Preferably, each support column depends from the cover and extends down and through to the bottom plate. At least one of support columns, preferably at least two, has a terminal end that is received and passed through a receptacle in the vent structure. The terminal end then protrudes through the receptacle to an exterior portion of the vent structure whereby a locking mechanism such as a key or combination lock may be affixed to the protruding terminal end. To further protect against unauthorized access, a guard for protecting the locking mechanism extends outward from the bottom plate to form a barrier around the locking mechanism.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:  
         [0011]      FIG. 1  is an exploded perspective view of an intruder resistant vent structure for use on a water storage tank;  
         [0012]      FIG. 2  is a side cross sectional view of the vent structure of  FIG. 1  shown affixed to a water storage tank;  
         [0013]      FIG. 3  is a bottom perspective view of the cover of the vent structure of  FIG. 1 ;  
         [0014]      FIG. 4  is a top planar view of the base of the vent structure of  FIG. 1 ; and  
         [0015]      FIG. 5  is a bottom perspective view of the flange of the vent structure of  FIG. 1 .  
     
    
     DETAILED DESCRIPTION  
       [0016]     Referring to  FIGS. 1 and 2 , a vent structure  10  shown in accordance with a preferred embodiment of the present invention is constructed to prevent unauthorized access by intruders, which may include rain, animals, leaves, trash, people, and other foreign matter, into a container to which vent structure  10  has been affixed. Particularly, vent structure  10  is designed to be employed with water storage tanks such as water tank  60 . However, other containers such as chemical storage tanks, transport vessels, and other storage devices requiring venting may employ the vent structure of the present invention. With water storage tanks, venting is provided to allow the open volume or air space within the tank to change without affecting its internal air pressure. Thereby, the flow of water into and out of the tank is not impeded by a contained mass of air within the tank.  
         [0017]     Vent structure  10  generally comprises a cover  20 , a bottom plate  30 , and a flange  50 . When assembled, vent structure  10  has a tortuous venting path formed with the use of baffles  26 ,  32 , and  34 , which does not substantially impede the flow of gases into or out of a tank. However, this tortuous venting path does deter the entry of undesired matter. Vent structure  10  is cylindrically shaped with one end sealed and the other end partially open for venting and for engaging a storage tank. While shown having a generally cylindrical shape, vent structure  10  may comprise other shapes such as, for example, a box.  
         [0018]     The components of vent structure  10  may be comprised of any material that is corrosion resistant and durable such as aluminum, stainless steel, steel, and fiberglass. In a preferred embodiment described herein, cover  20 , bottom plate  30 , and their depending parts comprise, unless noted otherwise, aircraft aluminum that has a corrosion resistant coating applied thereto. Coated aircraft aluminum is preferred because of its resistance to corrosion, durability, and cost.  
         [0019]      FIG. 3  shows an additional view of cover  20  having a top  28  and a peripheral edge  29 . As cover  20  is constructed to engage bottom plate  30 , one or more support columns  22  are provided within an interior portion of vent structure  10  to assist in supporting cover  20 . Each support column  22  has an opening  23  located at about its terminal end. Support columns  22  depend from top  28  toward bottom plate  30  wherein columns slots  33  are provided within bottom plate  30  for receiving the terminal ends of support columns  22 . Once assembled, openings  23  pass through columns slots  33  and extend beyond the external underside of bottom plate  30  to provide for the application of one or more locks  38  if desired. For additional security, an optional guard cover  36  is provided on the underside of bottom plate  30  around the periphery of each column slot  33 . Guard cover  36  extends outward from the underside of bottom plate  30  and protects any locking mechanism such as locks  38  that are subsequently attached to opening  23 . While the terminal ends of support columns  22  are shown having openings  23 , an alternative design of the terminal ends may employ flattened ends for engaging the internal top side of bottom plate  30 . In another alternative embodiment not shown, the support columns may stem upward from bottom plate  30  toward top  28 .  
         [0020]     In addition to support columns  22  and locks  38 , one or more bolts  24  may be used to secure cover  20  to bottom plate  30 . In application, each bolt  24  is inserted through a cover bolt hole  25  and is received by bottom plate bolt hole  27  located on bottom plate peripheral edge  31 . To retain bolt  24  in position after insertion through holes  25  and  27 , a nut (not shown) is applied to the end of bolt  24 . In addition to or in replacement of bolts  24 , other fasteners, such as rivets, adhesives, or welding may be employed.  
         [0021]     Bottom plate  30  has at least one vent opening  40  for allowing air to pass into or out of vent structure  10 . As shown in further detail in  FIG. 4 , a plurality of vent openings  40  are provided in a preferred embodiment. Each opening  40  is disposed between edge  31  and bottom cover outer baffle  32 . Vent opening screen  46  is affixed to the vent opening screen frame  42  to provide a first deterrent to prevent any unwanted foreign matter from entering into vent structure  10  and, subsequently, water tank  60 . Screen  46  is preferably comprised of a fine mesh and is comprised of stainless steel for its strength and corrosion resistance. Frame  42  is also preferably comprised of stainless steel for its strength and corrosion resistance. With the placement of vent openings  40  on the underside of vent structure  10 , the opening into vent structure  10  is less likely to become obstructed with debris such as leaves and trash.  
         [0022]     Securing frame  42  and vent opening screen  46  to the top portion of bottom plate  30  are one or more bolts  44 . Therein, each bolt  44  is inserted through an optional washer  45 , then through one of the screen bolt holes  47  located along vent opening frame  42 . The bolt  44  is then subsequently inserted through a corresponding screen bolt hole  48  in bottom plate  30 . Once in position, each bolt  44  is secured into position with the preferable use of a screen bolt nut  49  affixed to the terminal end of each bolt  44 . Furthermore, a plurality of bolts applied about the circumference of frame  42  is preferably used to retain screen  46  in position upon bottom plate  30  to provide increased intruder protection. Bolts  44 , washers  45 , and nuts  49  are preferably comprised of stainless steel for strength and durability. In addition to or in replacement of bolts  44  and associated hardware, other fasteners, such as rivets, adhesives, or welding, may be employed to secure frame  42  and vent opening screen  46  to bottom plate  30 .  
         [0023]     To affix the vent structure  10  to a water tank, a flange  50 , as shown in further detail in  FIGS. 2 and 5 , is mounted onto a tank vent opening such as tank vent  62 . Flange  50  is preferably comprised of cast iron and has an optional screen  56 , which is preferably comprised of stainless steel for strength and durability. Screen  56  is affixed to inner peripheral edge  52  of flange  50  so that screen  56  is in about the same plane as the top of bottom plate  30 . As shown in  FIGS. 1, 4 , and  5 , screen  56  provides an additional intruder barrier between vent structure  10  and water tank  60 . Thereby, opening  37  is covered by screen  56  upon attaching bottom plate  30  to flange  50 . For robust attachment of flange  50  to tank vent neck  64 , inner peripheral edge  52  extends beyond planar flange edge  57  toward water tank  60 . Flange  50  is then attached to tank vent neck  64  with welding, adhesives, and/or other fasteners to form a seal. Preferably, an essentially complete seal of edge  52  to tank vent neck  64  is desired to prevent intruders from bypassing vent structure  10  to obtain access to the interior of water tank  60 .  
         [0024]     Flange  50  is adapted for mating with the underside of bottom plate  30  at about the bottom plate tank opening  37 , which is disposed centrally in bottom plate  30 . To retain bottom plate  30  to flange  50 , one or more flange bolts  51  are provided for insertion through flange bolt holes  54  and then through a corresponding bottom plate flange bolt hole  58 . Flange bolt holes  54  are formed radially through and along the planar flange edge  57  for alignment with bottom plate flange bolt holes  58 , which are disposed radially about opening  37 . To render the attachment of bottom plate  30  to flange  50  robust, a plurality of flange bolt holes  54  and bottom plate flange bolt holes  58  are provided around the circumference of opening  37  for the placement of flange bolts  51  therethrough. In application, each flange bolt  51  is inserted through a flange bolt washer  53 , flange bolt hole  54 , bottom plate flange bolt hole  58 , and then another flange bolt washer  53 . A flange bolt nut  55  is applied to the terminal end of each flange bolt  51  to retain it in the desired position. Bolts  51 , washers  53 , and nuts  55  are preferably comprised of stainless steel for strength and durability. In addition to or in replacement of bolts  51  and associated hardware, other fasteners, such as rivets, adhesives, or welding, may be employed to secure bottom plate  30  to flange  50 .  
         [0025]     Once assembled and positioned atop water tank  60 , venting may proceed as shown in  FIG. 2 . For the occurrence of atmospheric air venting into water tank  60 , a current of air passes through vent opening  40  and vent opening screen  46  up toward cover top  28 . The current of air then passes down toward bottom plate  30  passing over baffle  32 . Thereafter, the current of air passes up between baffles  26  and  34  toward cover top  28 . Finally, the current of air passes down toward and through flange screen  56  for entrance into water tank  60  via water tank vent  62 . For the occurrence of air venting out from water tank  60  into the atmosphere, the venting process described above is reversed.  
         [0026]     With the use of a vent cover made in accordance with the present invention such as vent structure  10 , a water tank can be adequately ventilated while restricting access to the interior of the tank. Unlike prior art vent covers for water tanks, the durable and robust venting structure  10  provides sufficient airflow into and out of the tank while providing improved security.  
         [0027]     Particularly with the public&#39;s concern and need for safe and adequate sources of water, a protective device such as the present invention is of significant importance. This is because vent structures made in accordance with the present invention provide resistance to intruders whether they are naturally occurring or not. For naturally occurring intruders such as rain, animals, leaves, and other foreign matter, the screens, tortuous air path, and other features of the present invention will prevent their entrance into the interior of the water tank via the protected tank vent.  
         [0028]     For intruders such as terrorists, vandals, or other unwanted trespassers, the screens, tortuous air path, locks, robustness and durability of the construction materials, and others features of the present invention, will prevent or at least deter trespassers from introducing unwanted matter into the water tank protected by the vent structure. If, for example, a trespasser wanted to introduce a harmful chemical into the water tank via a hose, a vent opening screen  46  would prevent entry of the hose into vent structure  10 . If the trespasser attempted to spray up into the vent structure through a vent opening screen  46 , the tortuous path would prevent entry into water tank  60 . Because vent structure  10  significantly increases the difficulty of introducing an unwanted substance into water tank  60  by a trespasser, a trespasser may be inclined to apply more extreme measures with the use of, for example, a blow torch, explosives, or other destructive instruments. These however are impractical and are likely to draw the attention of law enforcement or other security forces.  
         [0029]     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.