Expandable-Volume Liner for a Collapsible Liquid Holding Tank

This application claims priority to U.S. application Ser. No. 17/134,980, filed Dec. 28, 2020, which claims priority to U.S. application Ser. No. 15/927,700, filed Mar. 21, 2018, which claims priority to U.S. application Ser. No. 14/629,138 filed Feb. 23, 2015, which claims priority to and benefit of U.S. Provisional Application No. 62/113,202 which was filed Feb. 6, 2015.

This invention relates generally to collapsible portable tanks for storing liquids and more particularly concerns the pliant, impermeable liners used with such tanks.

Portable tanks for storing liquids typically consist of a frame of rigid top and bottom rails spaced by rigid vertical struts. The corners of the tank and the midpoints of two opposite top and bottom rails are hinged. The opposed hinged rails can be V-folded toward the center of the tank until the other rails come together in parallel. My earlier U.S. Pat. No. 8,746,478 describes one type of collapsible tank frame in detail, noting that such tanks are usually about 30″ high, from 6′ to 18′ on each side and capable of holding from 500 to 5,000 gallons of water.

Whatever the size of the tank and the nature of the collapsible hardware, the frame generally unfolds into a predetermined and invariable square or rectangular footprint. More recently, frames have been designed with multiple hinges in opposite side rails allowing the same frame to be unfolded into one of two such footprints.

The tanks are often necessary in firefighting scenarios in which water is not readily accessible at the site. In practice, the folded tank is stored on, and transported by, a fire truck dispatched to the site of the fire. On site, the tank frame is unloaded, unfolded and filled with water carried by a tanker truck to the site. The tanker truck may be the transporting fire truck. As the water is being exhausted from the tank by the firefighters, the tanker truck travels to and from a water supply station to refill the tank.

Folded tanks are usually stored on the rack of a transporting fire truck and, in common practice, only one tank is stored on the truck. The possibility of storing multiple tanks on the same truck is an expensive, space eating and deployment-time increasing luxury rarely used in firefighting applications. But the tank to be used in a given application must take into account the demands of the fire and the distance from the deployed tank to a remote water supply for refilling the tank. So two competing criteria, volume and footprint, have a major impact on the decision as to the size of the tank to be stored on the transporting truck. On one hand, in order to accommodate a wider range of possible storage capacity requirements, a larger tank is preferred. On the other hand, because of unique site features, such as irregular terrain or immovable obstacles, the largest site footprint available may be quite restricted. Therefore, in order to accommodate a wider range of footprint alternatives, a smaller tank is preferred.

It is, therefore, an object of the invention to provide a liquid storing collapsible portable tank having a footprint changeable to comply with a footprint presented by the site at which the tank will be used. And it is a further object of this invention to provide a liquid storing collapsible portable tank of expandable maximum volume.

In accordance with the invention, a liner is provided for a collapsible, portable, liquid holding tank frame having top and bottom rails spaced apart by vertical struts. The liner has pliant impervious side walls and a pliant impervious floor panel. At least one opening through the pliant impervious side walls is sized to be surrounded by the top and bottom rails and two adjacent struts of the frame. At least one pliant impervious collapsible bag, one for each opening, has a mouth welded to its corresponding opening. Each bag is extendable from its mouth between its respective surrounding top and bottom rails and adjacent struts and outwardly from the side walls to its closed end. Each mouth has at least one strap connectable at one of its ends to the top or bottom rail and at its other end to the bottom or top rail, respectively. Each strap extends between its corresponding adjacent struts so that its corresponding bag, when folded from its closed end to its mouth into a stored condition, can be secured in the stored condition by its at least one strap.

While the invention will be described in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment or to the details of the construction or arrangement of parts illustrated in the accompanying drawings.

Looking at, a collapsible, portable, liquid-holding tank frameis seen in an empty condition. The frameshown has top and bottom railsandspaced apart by vertical strutsand hinged at the four corners and mid-points of two opposite sides of the frame. The framesupports a linerformed by pliant, impervious side wallsand a pliant, impervious floor panel. As shown, the upper edges of the sidewallsare fitted with grommetsand are secured by lacingto the top rails.

At least one opening, and as shown four openings, are provided through the liner side walls. Each openingis surrounded by two proximal adjacent strutsof the frameand the portions of the top and bottom railsandof the framelying between its two proximal adjacent struts. As shown, each of the four top and bottom railsandof the tank frameare spaced by six struts, so each side wallappears in five side wall segments. However, any number of strutsat any desired spacing could be used.

For the tank shown, at least one of the segments is adapted to provide a drain passagefor evacuation of liquid from the linerafter use. Thus, the linershown has nineteen wall segments, five in each of three side wallsand four in the other side wall, through which openingscould be provided. However, in the illustrated application, only four of the segments have openings. As best seen in, when the lineris filled with liquid, the drain passagewill have been folded over the top railand secured to the inside face of its side wall.

Returning to, at least one pliant, impervious, collapsible bagis provided, one for each openingthrough the side walls. The mouthof each bagis welded or otherwise sealed along its perimeter to the perimeter of its corresponding openingthrough the side walls. As shown, each bagcan be independently and optionally extended from its mouthoutwardly from its respective liner side wall.

Continuing to look at, for storage, each bagcan be, and one of the bagshas been, folded from its closed endto its mouth. The folded bagmay then be secured in the folded condition against the tank side wall by strapsor other types of fasteners. At least one and, as shown two, strapscan be used between the corresponding adjacent strutsof their respective bags. As best seen in, the lower end of each strapis connectable to the bottom railor to the tank linerproximate the bottom rail, as shown by wrapping the lower end of the straparound the lower railand fastening it to itself with hook-and-loop fasteners. The strapis then extendable upwardly across the folded bagand over top railand connectable at its upper end to the inside of the tank wallbetween the corresponding adjacent struts, perhaps by snaps, buckles or, as shown, mating segments of hook-and-loop material. The strapsmay be narrow, as shown, or wide enough to extend fully across their respective bagsin the stored condition. The four segments having openings are preferably, and as shown, in hinged mid-point wallsof the tank so that, when the tank is collapsed, the folded bagsare interior to the collapsed liner.

Returning to, in deploying a tank on a site, the tank frameis oriented on the site in a manner which will permit the liner floor paneland any bagsintended to be extended from the tank to lie within the site footprint. The frameand linerare unfolded and secured in their orthogonal use configuration. The strapsor other mechanisms used to secure the bagsin the stored condition are then disconnected and the bagsextended outwardly from the tank between their respective vertical struts. Any number of bagssuited to the site footprint and needed for increased tank volume can be extended. For the embodiment as shown, the tank includes and extends four bags.

Turning now to, the deployed tank has been filled with liquid which, for many applications and particularly for firefighting applications, will be water W. The linerand the extended bagswill be simultaneously filled with water W as the liquid level rises in the tank. Thus, the collapsible bagsincrease the storage capacity of the tank while simultaneously allowing the linerto fit within the standard frame dimensions for the desired size of tank. For example, by extending one 500 gallon bagfrom an otherwise 2,000 gallon linerassociated with a 2,000 gallon frame, a tank capacity of 2,500 gallons of water W is possible using the 2,000 gallon frame. The extension of two bagswould afford a tank capacity of 3,000 gallons of water W using the same frame.

Looking at, gripsare shown fixed to the floor panelof the linerfor use in manipulating the linerto aid in discharging the liquid from the linerand/or to collapse the tank after use. Similarly, one or more gripsmay also be fixed to the collapsible bagsto aid in discharging liquid from the extended bagsand/or to fold the extended bagsafter use.

The increase in storage capacity without any corresponding increase in frame size minimizes the costs and the deployment time, and simplifies the transportation and storage, of the tank. Furthermore, a collapsible bag linercan be deployed in an existing standard-liner frame, thereby increasing storage capacity while totally eliminating the cost of acquiring a new frame. And, by selection of appropriate bagsfor extension, the footprint of the expanded volume tank can be tailored to suit the footprint presented by the site.

Thus, it is apparent that there has been provided, in accordance with the invention, an expandable-volume liner for a collapsible liquid holding tank has been provided that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with a specific embodiment thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.