Abstract:
Embodiments of the present invention relate to apparatuses, systems, and methods for constructing, installing, and using an inflatable hatch sealing device in environmentally sealing a manhole. In particular, the inflatable hatch sealing device has a sealing assembly with a directed inflatable air bladder, and the sealing assembly is rotatable relative to a contact disc.

Description:
BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     Implementations of the present invention relate, generally, to the field of reducing environmental pollution during transport or storage of liquids. More particularly, implementations of the present invention are adapted for use in openings for the filling of large transportation and storage tanks, known as manholes. 
     2. The Relevant Technology 
     The present invention relates to the liquid storage and transportation industry. In particular, implementations of the present invention relate to the sealing of manholes used as access points to large storage and transportation tanks. These tanks are commonly used in the containment of liquids such as gasoline, diesel fuel, heating oil, and other fuels; acids; alkalis; and other liquid chemical products. Many of these liquids are volatile compounds or may otherwise enter the atmosphere. Even those that are not particularly volatile may have negative environmental impacts if spilled from their containers. 
     Environmental pollution concerns from tank filling are similar to pollution concerns from filling an automobile gas tank. On a small scale, the problem can be overcome with a vapor control nozzle, as are commonly used in the automobile fueling industry. However, the challenge is amplified on the scale of a bulk transport tank. A typical tanker trailer can hold up to 11,600 U.S. gallons. Due to the large capacity of the trailers, the filling rates must be large, as well. A common filling method is the discharge of liquids into a large opening in the top of the tank called a manhole. The liquid is delivered to the manhole through a conduit known as a loading boom. Loading booms can deliver liquid at a rate of 50-100 gallons per minute or more. Despite being a seemingly smaller effect than spills, vapors released during the filling process may escape and, in sum, account for a larger release of a compound than from spills of liquid. Therefore, a number of solutions have been proposed aimed at reducing the chance or effect of both sources of pollution from the filling of bulk transport tanks. 
     For instance, one device consists of a filler tube and vapor recovery vent incorporated into a single, cylindrical body that is lowered into place within a manhole. The filler tube allows for the loading boom to discharge liquid into the tank without constraint, and the vapor recovery vent can be connected to a vapor recovery system. Thereby, the filling station can fill the tank at the conventional rate while capturing the vapors generated during the filling process. The body is lowered into place and fixed there with a lockdown bar across the top of the device. The entire device hangs from the lockdown bar affixed the top of the manhole at contact points. The contact points and the lockdown bars allow the device to be secured to the manhole in only two positions that are offset from one another by 180 degrees. 
     The device has a flexible tube stretched around the perimeter of the device between an outer wall of the body of the device and the interior wall of the manhole. The flexible tube can be deployed to create an annular seal around the cylindrical body. However, while expanding radially, and eventually against the interior wall of the manhole, the tube also expands longitudinally. Inflation of the seal is, therefore, imprecise. Mere contact between the tube and the wall does not ensure a robust seal, while increased inflation undesirably expands the tube longitudinally, leading to overinflation and weakening of the tube. 
     Likewise, the device includes a recessed top area that can lead to a number of problems. The recessed top area can act as a well that can accumulate dirt, gravel, ice, water, snow, or any other airborne debris that occurs at filling stations or during storage of the device. This can make the device less reliable or slower to use, as well as shorten the life of the connections housed in the body. 
     Thus, there are a number of problems that can be addressed with manhole sealing devices. 
     BRIEF SUMMARY OF THE INVENTION 
     Implementations of the present invention relate to the environmental sealing of a hatch, commonly referred to as a manhole, during filling of a bulk liquid storage or transportation tank. In particular, implementations of the present invention provide a manhole sealing device that that will quickly and easily seal manholes of various configurations. Further implementations of the present invention provide devices that include a rotatable attachment to the manhole that also allows for optimal alignment of the conduits through the device. 
     In one example embodiment of the present invention, a device for environmentally sealing a manhole during the filling of a liquid transport tank includes a contact disc and a sealing assembly that are rotatably connected to one another. The contact disc may be selectively securable to the manhole. The sealing assembly may comprise an inflatable air bladder that is deployable to seal the manhole. The rotatable connection may provide a single axis of rotation of both the sealing assembly and the contact disc. 
     In another embodiment of the present invention, a device for environmentally sealing a manhole during the filling of a liquid transport tank includes an inflatable air bladder disposed on at least a portion of the outer surface of an annular sidewall. The expansion of the inflatable air bladder may be constrained on three sides by the annular sidewall, a first retention member, and a second retention member. The first and second retention members may extend substantially perpendicular to the annular sidewall. The constraint of the inflatable air bladder may be configured to direct the expansion of the air bladder laterally away from the annular sidewall and toward an inner wall of the manhole. 
     In another embodiment of the present invention, a device for environmentally sealing a manhole during the filling of a liquid transport tank includes a sealing assembly and a contact ring rotatably connected to one another. The sealing assembly may comprise an inflatable air bladder disposed on at least a portion of the outer surface of an annular sidewall. The inflation of the inflatable air bladder may be constrained longitudinally by first and second retention members. The retention members may extend substantially perpendicularly to the annular sidewall and direct the expansion of the inflatable air bladder toward the wall of the manhole. Further, there may be a surface extending over one end of the annulus defined by the annular sidewall. The surface may limit the accumulation of foreign debris within the annulus during storage or operation of the device. 
     These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only illustrated embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a perspective view of an inflatable hatch sealing device according to one implementation of the present invention. 
         FIG. 2  illustrates a perspective view of the inflatable hatch sealing device of  FIG. 1 , depicting a rotation mechanism of a contact disc. 
         FIG. 3  illustrates a bottom perspective view of the inflatable hatch sealing device of  FIG. 1 . 
         FIG. 4  illustrates a cross-section view of the inflatable hatch sealing device of  FIG. 1  with a seal undeployed. 
         FIG. 5  illustrates a cross-section view of the inflatable hatch sealing device of  FIG. 1  with the seal deployed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Implementations of the present invention relate to the environmental sealing of a hatch, commonly referred to as a manhole, during filling of a bulk liquid storage or transportation tank. In particular, implementations of the present invention provide a manhole sealing device that will quickly and easily seal manholes of various configurations. Further implementations of the present invention provide devices that include a rotatable attachment to the manhole that also allows for optimal alignment of conduits through the device. 
     For example, implementations of the present invention provide a sealing assembly with an efficient sealing mechanism. The sealing assembly includes an inflatable air bladder that is disposed on the outside of an annular sidewall of the assembly. The inflatable air bladder is then disposed within the manhole between an outer wall of the annular sidewall and the inner wall of manhole. To make the seal more robust and more efficient, the assembly then further comprises a pair of retention members at either end of the annular sidewall. The retention members extend substantially perpendicularly from the sidewall and flank the inflatable air bladder when the air bladder is undeployed. As air is introduced to the air bladder, the bladder expands. However, because the air bladder begins in contact with or nearly in contact with the annular sidewall and the two retention members, the air bladder can expand in substantially only one direction. Therefore, nearly any increase in pressure in the air bladder causes the air bladder to expand toward and then press against the inner wall of the manhole, creating a robust seal with little volume of air. 
     In another implementation of the present invention, a sealing assembly is mounted to the manhole cover with a rotatable contact disc. The contact disc allows for an operator to optimally align the connections in the assembly with the conduits at a filling station. For example, the manhole on a tank may have one or more bolts or other attachment points on the manhole. However, the particular orientation of those attachment points may not line up conveniently with a loading boom used to deliver the liquid to the tank or vapor recovery system used to collect hazardous vapors during filling. Instead of necessitating a repositioning of the tank or the usage of a non-ideal angle for the loading boom, an operator can simply align the sealing assembly with the loading boom by rotating the contact disc and sealing assembly relative to one another until the contact disc is aligned with the attachment points and the sealing assembly is aligned with the loading boom. 
       FIG. 1  depicts an inflatable hatch sealing device  10  comprising a surface plate  100 , a contact disc  200 , an air bladder  300 , a retention member  400 , and a sidewall  500  (visible in  FIG. 3 ) supporting the air bladder  300 . The surface plate  100 , air bladder  300 , retention member  400 , and sidewall  500 , collectively, form a sealing assembly. 
     The surface plate  100  includes a number of connections and valves to allow transmission of a liquid or a gas through the sealing device  10 . The surface plate  100  may rest substantially flush with the top of a manhole  20  above a tank  30 . The surface plate  100  being flush with the top of the manhole  20  allows the incorporated connections to stand above or at about the same level as the surface of the manhole  20 . Standing above or at about the same level as the surface of the manhole  20  may prevent the accumulation of water, dirt, gravel, or other debris in or around the connections or on the sealing device  10 . This increases the ease of use of the connections and can speed the filling process. In addition, without the accumulation of water, for example, while raining, the sealing device  10  will not increase in weight. A lighter sealing device  10  eases movement of the device before and after the filling process. Furthermore, with less material accumulating on the surface, there is less risk of contamination to the contents of the tank being filled. 
     In the illustrated embodiment, the surface plate  100  comprises a fill pipe  102 , a vapor recovery pipe  104 , a pressure relief valve  106 , an air bladder connector  108 , an air bladder pipe  110 , a level sensor  112 , and at least one handle  114 . The fill pipe  102  may be threaded, include a twist lock, a clamp, or have other connections to affix a loading boom or other conduit to the fill pipe  102 , if desired. 
     The vapor recovery pipe  104  may be connected to a vapor recovery system (not shown) during filling. A vapor recovery system will trap the vapors released by the liquid during filling of the tank  30  and contain the vapor for other handling. Vapors may be expelled during filling due to increased evaporation from the energy imparted to the liquid during the filling process, as well as due to the increased surface area from the agitation of filling. Furthermore, filling the tank  30  with liquid will displace any vapors produced. To assist the air bladder  300  in sealing the manhole  20 , pressure in the tank  30  can be managed by collecting the vapors in a recovery system. 
     If there is a blockage in the vapor recovery system, however, pressures in the tank  30  may increase to unsafe levels. In such a situation, vapors may escape from the tank  30 . Escaping gas under pressure could potentially damage the air bladder  300  or be dangerous to operators. The surface plate  100  may include a pressure relief valve  106  to enable venting of the tank pressure in a controlled manner before the pressure reaches an unsafe level. 
     The surface plate  100  may include an air bladder connector  108  and an air bladder pipe  110 . The air bladder connector  108  may be any appropriate type of connector to enable fluid communication with the air bladder pipe  110 . The air bladder pipe  110  extends from the air bladder connector  108  through the surface plate  100 . As shown in  FIG. 3 , the air bladder pipe  110  connects through the sidewall  500  to the air bladder  300 . The air bladder  300  can, therefore, be inflated and deflated after the sealing device  10  is lowered into the manhole via the air bladder connector  108  and pipe  110 . In addition, the air bladder connection  108  may include a valve for the discharge of air within the air bladder  300  for deflating the air bladder  300 . 
     Further, the surface plate  100  may be configured with a level sensor  112 . Level sensors are needed during the filling process because there may not be any ability to directly visually inspect the liquid levels in the tank  30 , and the loading boom or other conduit may be capable of very high flow rates. The liquid levels can change quickly and with accompanying rapid pressure changes in the tank  30 . As explained in context of the pressure relief valve  106 , rapid pressure changes can be dangerous both to the sealing device  10  and personnel. Pressure changes are most rapid as the fill level reaches the top of the tank  30 , and the level change can accelerate as the fill level approaches the top of the tank  30  because most transport tanks are horizontal cylindrical containers. There are a number of level sensors available in the industry including a vibrating fork level sensor, such as level sensor  112  illustrated in  FIG. 1 , SONAR-based sensors, RADAR-based sensors, and other types of sensors known in the art. 
     The surface plate  100  may include one or more handles  114  to simplify placement and removal of the sealing device  10  from the manhole  20 . One or more handles  114  may be affixed to the surface plate  100  to assist movement of the sealing device  10  and to facilitate rotation of the surface plate  100  relative to the contact disc  200  when affixed to a manhole  20 . Rotation of the surface plate  100  can allow alignment of the connections in the surface plate  100  with the appropriate conduits, which can ease use of the sealing device  10  at filling stations. In addition or in the alternative, one or more handles  114  may be disposed on the contact disc  200 . Locating one or more handles  114  on the contact disc  200  may allow an operator to apply torque to the surface plate  100  more easily and safely. 
     Still referring to  FIG. 1 , the contact disc  200  may be an annular disc that comprises openings  202  to mate with bolts on the manhole. The openings  202  may also be holes, recesses, notches, or similar structures. The sealing device  10  is rotatable relative to the manhole  20 . The manhole  20 , however, may have an array of bolts  22  around the periphery of the opening. The bolts  22  may be a useful fixture point to secure the sealing device  10  to the manhole  20 , but the bolts  22  may not be oriented or arranged conveniently for the various conduits an operator may use. The openings  202 , as well as the shape of the contact disc  200 , generally, may be spaced to facilitate more than one format of manhole. 
     In addition, the contact disc  200  and surface plate  100  may have a freely rotatable connection therebetween. As can be seen in  FIGS. 1 and 2 , the rotatable connection may comprise a plurality of notched posts  204  that may be affixed to the surface plate  100 . The notched posts  204  may be affixed to the surface plate  100  and have an upper portion that overhangs the contact disc  200 . The overhang may allow sufficient tolerance with a thickness of the contact disc  200  such that the contact disc  200  can rotate relative to the surface plate  100  while remaining attached to the surface plate  100 . In the example embodiment illustrated in  FIG. 4 , the surface plate  100  and the contact disc  200  may be selectively locked together by compression of the surface plate  100  between the manhole  20  and the contact disc  200 . The compression force may originate from any compressive connection between the manhole  20  and the contact disc  200 . In the illustrated embodiment, the bolts  22  may provide the compression force in conjunction with nuts  24  (such as those visible in  FIGS. 4 and 5 ). In another embodiment, the contact disc  200  may be in contact with the manhole  20  and the surface plate  100  may not be. In such an embodiment, the sealing assembly may still rotate freely after the contact disc  200  is secured to the manhole  20 . 
     Referring now to  FIG. 3 , in an embodiment, the air bladder  300  may be disposed between the surface plate  100  and the retention member  400 . The air bladder  300  may be disposed around the entire periphery of the sidewall  500  and may contact the sidewall  500  when in an undeployed state. The constraint on three sides of the air bladder  300  may direct expansion of the air bladder  300  primarily laterally and substantially prevent expansion or movement of the air bladder  300  longitudinally with respect to the sidewall  500  and manhole  20 . The constraint of the air bladder  300  may be performed by the sidewall  500  and at least two retention members. In an embodiment, the air bladder  300  may be constrained by the surface plate  100 , retention member  400 , and sidewall  500 , wherein the surface plate  100  performs the function of a second retention member. In another embodiment, the second retention member and the surface plate may be distinct portions of the device. 
     The air bladder  300  may be made of an elastic material to allow expansion of the air bladder  300  with increase in internal pressure. The air bladder  300  may have an air stem  302  to allow connection of the air bladder pipe  110  and the air bladder  300 . The air stem  302  may pass through a bladder connection port  502  in the sidewall  500 . In an embodiment, the bladder connection port  502  is a notch that restrains motion of the air stem with respect to the sidewall  500  in either direction laterally and toward the surface plate  100  longitudinally. A notch configuration also provides the benefit of facilitating replacement of the air bladder  300  if it becomes worn or damaged. The air stem  302  may slide out of the notch when the retention bolts  402  are loosened and the retention member  400  is removed. Alternatively, the bladder connection port  502  may, in addition, restrain motion of the air stem  302  in both directions longitudinally. 
     Referring now to  FIG. 4 , the retention member  400  is connected to the sidewall  500  by the retention bolts  402 . The retention member  400  may extend laterally beyond the sidewall  500  and beyond the air bladder  300  when the air bladder  300  is in a undeployed state, as shown in  FIG. 4 . The retention member  400  has an outer diameter smaller than a diameter of a manhole inner wall  26 . In an embodiment, the retention member  400  may have an outer diameter less than 6″ smaller than the diameter of the manhole inner wall  26 . In another embodiment, the retention member  400  may have an outer diameter of greater than 6″ smaller than the diameter of the manhole inner wall  26 . In yet another embodiment, the retention member  400  may have an outer diameter of about 3″ smaller than the diameter of the manhole inner wall  26 . In yet another embodiment, the retention member  400  may have an outer diameter of about 2″ smaller than the diameter of the manhole inner wall  26 . 
     The outer diameter of the retention member  400  should allow an operator to place the sealing device  10  into the manhole  20  but also extend beyond the air bladder  300  when the air bladder  300  is in an undeployed state. The ratio of the difference between the outer diameter of the retention member  400  and the outer diameter of the annular sidewall  500  and the difference between the outer diameter of the undeployed air bladder  300  and the outer diameter of the annular sidewall  500  is the “undeployed ratio.” In an embodiment, the undeployed ratio is less than about 3:2. In another embodiment, the undeployed ratio is between about 3:2 and about 3:1. In yet another embodiment, the undeployed ratio is greater than about 3:1. 
     The ratio of the difference between the outer diameter of the retention member  400  and the outer diameter of the annular sidewall  500  and the difference between the outer diameter of the deployed air bladder  300  and the outer diameter of the annular sidewall  500  is the “deployed ratio.” In an embodiment, the deployed ratio is less than about 2:3. In another embodiment, the deployed ratio is between about 2:3 and about 1:3. In yet another embodiment, the deployed ratio is greater than about 1:3. The deployed and undeployed ratios may apply as well to the surface plate  100  when the surface plate  100  performs the function of the second retention member, as well. 
     As can be seen in  FIGS. 4 and 5 , the retention member  400  may work in conjunction with the surface plate  100  to direct the expansion of the air bladder  300  laterally with respect to the sidewall  500  and manhole inner wall  26 . In bounding the expansion of the air bladder  300  longitudinally, an increase in volume of the air bladder  300  will result in a substantially lateral expansion of the air bladder  300  toward the manhole inner wall  26 . Bounding the air bladder  300  longitudinally also causes a greater increase in air bladder diameter for the same amount of increase in volume. Therefore, an operator can provide gas to the air bladder  300  through the air bladder connector  108  and pipe  110 , expand the air bladder  300 , and attain a satisfactory seal between the air bladder  300  and the manhole inner wall  26  in a shorter period of time versus an unbounded air bladder. 
     In addition to bounding the expansion of the air bladder  300 , the retention member  400  may also serve to protect the air bladder  300  during use, transportation, and storage of the sealing device  10 . In the absence of a retention member  400  having a larger diameter than the air bladder  300  in an undeployed state, the air bladder  300  could strike the wall of the manhole  20  during installation and removal of the device, potentially causing damage to the air bladder  300 . Furthermore, a device without a retention member having a larger diameter than the air bladder  300  in an undeployed state could be stored on its side when not in use, resting directly upon the air bladder. With the retention member  400  having a larger diameter than the air bladder  300  in an undeployed state, the air bladder  300  is more protected and may perform better and for a longer period of time before needing replacement. 
     As shown in  FIG. 4 , an operator may lift an inflatable hatch sealing device  10  by the handles  114  and place the device  10  on top of and covering a manhole  20  leading into a tank  30 . The operator can align the notches  202  in the contact disc  200  with one or more manhole bolts  22 , and, if necessary, may secure the sealing device  10  with nuts  24 . Once the contact disc  200  is placed upon the manhole  20 , the contact disc  200  can remain stationary, as the rest of the sealing device  10  is rotated using the handles  114  until the operator has aligned any necessary connections with their respective conduits. 
     Next, the operator can connect a source of air, such as an air compressor, compressed air tank, or similar, to the air bladder connector  108 . Once connected, the source of gas is in fluid communication with the air bladder  300  via the air bladder pipe  110 . As seen in  FIG. 5 , the air bladder  300  may expand laterally when filled with air, extending beyond the outer diameter of the retention member  400  and contacting the inner wall  26  of the manhole  20 . With the longitudinal bounding of the air bladder  300  by the surface plate  100  and the retention member  400 , the air bladder  300  may be “deployed” and thereby form a sufficient seal with the manhole wall  26  for environmental protection purposes at a low air pressure in the air bladder  300 . In an embodiment, the air bladder is deployed at between about 5-10 psi. In another embodiment, the air bladder  300  is deployed at between about 10-13 psi. In yet another embodiment, the air bladder is deployed at between about 13-15 psi. 
     Once the air bladder  300  is deployed, the operator may connect a loading boom to the fill pipe  102  and a vapor recovery system to the vapor recovery pipe  104 . Upon completion of the filling process, the operator can remove the loading boom and vapor recovery systems from the fill pipe  102  and vapor recovery pipe  104 , respectively, and then deflate the air bladder  300  via the air bladder connector  108 . Once the air bladder  300  is undeployed, any nuts  24  may be removed from the manhole bolts  22  and the inflatable hatch sealing device  10  may be lifted off of the manhole  20  by the handles  114 . 
     The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.