The present invention relates generally to tanks for containing liquids and more particularly to a septic tank for containing waste water having an internal strut/brace for increased structural integrity.
Molded plastic septic tanks for holding and processing wastewater are well known and have been used in place of traditional concrete septic tanks. These plastic septic tanks, which may be made by blow molding or rotational molding, generally have a cylindrical shape and may have a rectangular or round cross section. Typically, these plastic septic tanks are made of polyethylene and have thicknesses that range from one-quarter to three-eighths of an inch. Additionally, they often include heavily ribbed or corrugated sections for increased strength to resist the unique forces applied to the tank structure when buried in soil. The volume capacity for a typical domestic septic system is in the range of 1000-1500 gallons and septic tanks must have access ports with closures, to permit maintenance. Moreover, most septic tanks have at least one baffle to limit the lengthwise flow within the tank and to divide the tank into an input end portion and an output end portion. Furthermore, because septic tanks are buried beneath soil, they must also resist the weight of overlying soils and possible vehicles or other weighted objects that may be placed on the soil surface in proximity to the tank.
It should be appreciated that molded plastic septic tanks include some advantages to concrete tanks, such as light weight construction, better resistance to impact damage and corrosion, and improved resistance to thermal damage in the event of freezing. Unfortunately however, molded plastic septic tanks also include some disadvantages, such as being lightweight (which makes them buoyant) and as such, the tanks tend to rise out of the soil under which they are buried. Moreover, another disadvantage involves the limited structural rigidity of the tank as a result of its lightweight construction. This limited structural rigidity can result in distortion during installation and use. In the past few years, some state regulatory agencies have required that septic tanks pass certain tests which measure the propensity of the tank to distort during installation or use. In one kind of test, a two-piece septic tank is subjected to a partial vacuum, e.g., a pressure of about 5.8 inches of Hg less than standard atmospheric pressure, which tends to pull the walls of the tank inwardly. Such a vacuum is meant to simulate the pressure on an emptied tank when it is buried in soil, particularly in wet or non-cohesive soil.
One way the above issues with prior art plastic septic tanks have been addressed involve including structural corrugations and other features for resisting the foregoing kinds of loads. However, in making these septic tanks, the weight and cost of the plastic materials are a major consideration. Therefore, one design objective may be to maximize the volume to surface area ratio, while another consideration may be to limit the size of excavation which is required to install the tank. One approach may include having oblong cross section tanks, e.g., where the cross section approximates a rectangle or square. Unfortunately however, such shapes can present relatively large, lightly curved or nearly flat surfaces. Accordingly, septic tanks of such shape will most likely need more strengthening in certain areas than does a nearly circular cross section tank.
Furthermore, septic tanks which have generally circumferential corrugations, with any cross section, can be susceptible to lengthwise contraction when subjected to interior vacuum or to soil forces which apply similar forces. This lengthwise contraction, sometimes referred to as “accordioning”, is undesirable, because if the tank shrinks in length when installed, or if it otherwise deforms, the soil in response moves inwardly to occupy the space that was formerly occupied by the uncontracted tank. Thus, there can be an undesirable reduction in the nominal volume of the tank. Another factor which can affect the tank involves heating by the sun or atmosphere prior to installation. This heating can lower the stiffness of the plastic material thereby reducing the structural strength of the tank making it more susceptible to distortion during handling or initial installation. Accordingly, more strengthening may be needed for tanks than would appear from an analysis of the forces which result from being buried in soil.
A septic tank is provided and includes a tank top section having tank top side walls and tank top end walls which define a tank top cavity, wherein the tank top section includes a tank top opening surrounded by a top opening edge and communicated with the tank top cavity. The septic tank also includes a tank bottom section having tank bottom side walls and tank bottom end walls which define a tank bottom cavity, wherein the tank bottom section includes a tank bottom opening surrounded by a bottom opening edge and communicated with the tank bottom cavity, wherein the top opening edge and bottom opening edge are configured to be connected together to form the septic tank such that the tank top cavity is adjacent to the tank bottom cavity to form the tank interior cavity.
Additionally, the septic tank includes at least one of, at least one end wall pocket located on an interior surface of the tank top end walls and tank bottom end walls, at least one side wall pocket located on an interior surface of the tank top side walls and tank bottom side walls and at least one internal support, wherein the internal support includes a first internal support end located within the at least one end wall pocket and a second internal support end located within the at least one side wall pocket. Moreover, the septic tank also includes a top channel structure that defines a top channel on an interior surface of the tank top section, wherein the top channel structure includes a top channel latch that extends into the top channel to define a top brace pocket, a bottom channel structure that defines a bottom channel on an interior surface of the tank bottom section, wherein the bottom channel structure includes a bottom channel latch that extends into the bottom channel to define a bottom brace pocket and a supporting brace having a first brace end and a second brace end, wherein the first brace end is configured to be located within the top brace pocket and the second brace end is configured to be located within the bottom brace pocket.
A septic tank is provided and includes a tank top, a tank bottom, a plurality of tank side walls and a plurality of tank end walls, wherein the tank top, tank bottom, plurality of tank side walls and plurality of tank end walls define a tank interior cavity. The septic tank also includes at least one end wall pocket located on an interior surface of at least one tank end wall, at least one side wall pocket located on an interior surface of at least one tank side wall and at least one supporting member having a first supporting member end located within at least one end wall pocket and a second supporting member end located within at least one side wall pocket. Moreover, the septic tank includes at least one supporting member being strong enough to limit distortion of the tank to a range of about 0.5% to 5% when a vacuum within a range of about 3 to 7 inches of Hg is applied to the tank interior.
A tank is provided and includes a tank top, a tank bottom and a tank side wall, wherein the tank top, tank bottom and tank side wall define a tank interior. Additionally, the tank includes a top channel structure that defines a top channel on an interior surface of the tank top, wherein the top channel structure includes a top channel latch that defines a top brace pocket and a bottom channel structure that defines a bottom channel on an interior surface of the tank bottom, wherein the bottom channel structure includes a bottom channel latch that defines a bottom brace pocket. The tank also includes a supporting brace having a first brace end and a second brace end, wherein the first brace end is configured to be located within the top brace pocket and the second brace end is configured to be located within the bottom brace pocket.
The foregoing and other features and advantages of the present invention should be more fully understood from the accompanying detailed description of illustrative embodiments taken in conjunction with the following Figures in which like elements are numbered alike in the several Figures:
d is a top-down side isometric view of one end of a tank bottom with the first, second and third internal supports of
In accordance with one embodiment of the present invention, an internal support for a two-piece (may include single or multi-piece as well) injection molded plastic septic tank is disclosed where the internal support is configured to increase the structural strength of the tank structure to better resist contraction/compression of the tank structure due to positive and/or negative pressure while buried within soil and/or while under vacuum test. As discussed further herein, these two-piece tanks typically include a tank bottom section and a tank top section that are configured to mate together to form a tank chamber for containing liquids (and other matter) therein. The tank may further include a mid-seam gasket that is located at the mating portion of the tank bottom section and tank top section to be between the tank bottom section and tank top section seal the tank chamber such that the tank chamber can contain liquids without leaking.
Referring to
It should be appreciated that when the tank bottom section 102 and the tank top section 104 are mated together the tank bottom section opening 108 and tank top section opening 114 are adjacent each other such that the tank bottom section interior cavity 106 and tank top section interior cavity 112 define a septic tank interior cavity 118. The tank top section 104 is mated to the tank bottom section 102 by locating the tank top section interface edge 116 onto the tank bottom section interface edge 110 such that they are aligned. A mid-seam gasket may be located at the interface of the tank top section interface edge 116 and the tank bottom section interface edge 110 to be located between the tank top section interface edge 116 and the tank bottom section interface edge 110. This advantageously seals the septic tank interior cavity 118 from the external environment and prevents the contents of the septic tank interior cavity 118 from leaking out of the tank 100. The tank bottom section 102 and tank top section 104 may be secured together via any method or device suitable to the desired end purpose, such as clips, pins, bolts, welding, etc.
Referring to
The tank bottom section 202 is illustrated and includes tank end walls 212 located on each end of the tank bottom section 202 and tank side walls 214 located on each side of the tank bottom section 202. The tank bottom section 202 is configured to mate with a tank top section (not shown) that may be identical to the tank bottom section 202 to define a septic tank interior cavity 206. On each end of the tank bottom section 202, the tank end walls 212 include a first end wall pocket 216 and a second end wall pocket 218 and the tank side walls include a first side wall pocket 220 and a second side wall pocket 222, where the first side wall pocket 220 is located on one side wall 214 and the second side wall pocket 222 is located on the other side wall 214. The first end wall pocket 216 is configured to be aligned with the first side wall pocket 220 and the second end wall pocket 218 is configured to be aligned with the second side wall pocket 222. A first internal support 224 is provided and is positioned such that one end of the first internal support 224 is located within the first end wall pocket 216 and the other end of the first internal support 224 is located within the first side wall pocket 220. Similarly, a second internal support 226 is provided and is positioned such that one end of the second internal support 226 is located within the second end wall pocket 218 and the other end of the second internal support 226 is located within the second side wall pocket 222
The first and second end wall pockets 216, 218 and first and second side wall pockets 220, 222 (only one side shown) are shown in more detail in
In accordance with the invention, the internal supports 224, 226 are preferably constructed from a rigid material capable of withstanding forces (compressive) on the tank end walls 212 and/or tank side walls 214 to limit distortion of the tank structure to between about 0.5% to 5% distortion (preferably to a 2% maximum distortion). For example, in one embodiment the first internal support 224 and second internal support 226 may be configured (located/arranged) and/or constructed from a rigid material capable of preventing the tank from distorting more than a maximum of about 2% when a vacuum of about 5.8 inches of Hg (range of 3″ to 7″ of Hg) is applied to the septic tank interior cavity 206. The first internal support 224 may be associated with the tank bottom section 202 by locating one end of the first internal support 224 in the first end wall pocket 216 and the other end of the first internal support 224 in the first side wall pocket 220. Similarly, the second internal support 226 may be associated with the tank bottom section 202 by locating one end of the second internal support 226 in the second end wall pocket 218 and the other end of the second internal support 226 in the second side wall pocket 222. It should be appreciated that, if desired, the first internal support 224 may be associated with the tank top section 204 by locating one end of the first internal support 224 in the first end wall pocket 216 and the other end of the first internal support 224 in the first side wall pocket 220. Similarly, the second internal support 226 may be associated with the tank top section 204 by locating one end of the second internal support 226 in the second end wall pocket 218 and the other end of the second internal support 226 in the second side wall pocket 222.
Additionally, it is contemplated that the end portions of the internal supports 224, 226 may rest within the end wall pockets 216, 218 and/or side wall pockets 220, 222 or the ends of the internal supports 224, 226 may be secured within the end wall pockets 216, 218 and/or side wall pockets 220, 222. For example, in one embodiment, the end portions of the internal supports 224, 226 may be secured within the end wall pockets 216, 218 and/or side wall pockets 220, 222 via a securing means, such as a clip, a screw, a bolt, an adhesive, etc. In another embodiment, the end wall pockets 216, 218 and/or side wall pockets 220, 222 may be configured to frictionally contain (such as via press fit) the end portions of the internal supports 224, 226. One way this press fit may be accomplished may include the walls of the end wall pockets 216, 218 and/or side wall pockets 220, 222 may have protruding portions (not shown) where the end portions of the internal supports 224, 226 would be ‘pressed’ into and snugly held within the pockets by the protruding portions. In still yet another embodiment, the end wall pockets 216, 218 and/or side wall pockets 220, 222 may be partially enclosed and the end portions of the internal supports 224, 226 may be inserted into the partially enclosed end wall pockets 216, 218 and/or side wall pockets 220, 222. In this case, the length of the internal supports 224, 226 may (or may not) be telescoping to be expandable/retractable, where the length of the internal supports 224, 226 could then be secured via a dowel/pin.
Referring to
Furthermore, as disclosed hereinabove and referring to
In still yet another embodiment and referring to
In addition, it is contemplated that the tank top section 204 which mates with the tank bottom section 202 to enclose the tank interior 206 may be identical to the tank bottom section 202 such that the tank top section 204 also may include the first internal support 224, the second internal support 226 and/or the third internal support 234 as briefly discussed hereinbefore. Moreover, in an additional embodiment the first internal support 224, the second internal support 226 and/or third internal support 234 may be sized to extend above the edges of the tank bottom section 202 (or tank top section 204) such that when the tank bottom section 202 and tank top section 204 are mated together the internal supports 224, 226, 234 are partially contained in the end wall pockets and/or side wall pockets of both the tank bottom section 202 and tank top section 203 to provide increased strength to the tank bottom section 202 and tank top section 204.
In still yet another embodiment, the internal supports 224, 226 and/or internal supports 224, 226, 234 may be constructed as a single article as shown in
In accordance with an additional embodiment of the invention and referring to
The method 700 further includes positioning the tank top section 204 onto the tank bottom section 202, such that the tank top section interface edge 116 is aligned with the tank bottom section interface edge 110, as shown in operational block 710. If desired, a mid-seam gasket may be located between the tank top section interface edge 116 and the tank bottom section interface edge 110 to seal the seam formed interface edges 110, 116. The top tank section 204 and the bottom tank section 202 are then securely connected together to form the septic tank 200, as shown in operational block 712.
It should be appreciated that as described above, the internal supports 224, 226, 234 may be assembled prior to connecting the tank top section 204 and the tank bottom section 202. Or in another embodiment, (such as where the internal supports 224, 226, 234 are expandable/retractable), they may be assembled after connecting the tank top section 204 and the tank bottom section 202 by accessing the tank interior portion 206 via a tank access port. Additionally, although the internal supports 224, 226, 234 and the method of assembling the internal supports 224, 226, 234, are discussed herein with regards to a two-piece tank, the invention may be adapted to single or multi-piece (i.e. more than two-piece) tanks.
In accordance with still yet another embodiment of the present invention, a septic tank 500 having one or more vertical braces or struts and a method for installing the vertical braces or struts in the septic tank is disclosed, wherein the septic tank may be a single-piece construction or a multi-piece construction and includes a tank top portion and a tank bottom portion. As discussed further hereinafter, the tank 500 includes a top pocket located on the tank top portion and a bottom pocket located on the tank bottom portion, where the tank top portion also includes a top channel which leads to the top pocket and/or the tank bottom portion includes a bottom channel which leads to the bottom pocket. The top pocket (and/or bottom pocket) is configured to receive and contain the vertical brace and the bottom channel (and/or top channel) includes a compressibly resilient member or latch whose natural configuration is to extend into the bottom channel (and/or top channel) where one edge of the compressibly resilient member or latch forms one wall of the bottom pocket (or top pocket). It should be appreciated that the pocket may be formed by complete walls or it may be formed by partial walls as disclosed hereinafter.
In one embodiment and as discussed further hereinafter, to install the vertical brace, one end of the vertical brace, which may be rectangular (square), round (cylindrical), triangular, or any other shape suitable to the desired end purpose, is located within the top pocket (or bottom pocket as the case may be) and the other end of the vertical brace is located in the bottom channel (or top channel as the case may be) such that the vertical brace is on an angle. The end of the vertical brace that is located in the bottom channel (or top channel) is then slid along the bottom channel (or top channel) toward the bottom pocket (or top pocket). As the end of the vertical brace encounters the compressibly resilient member or latch, the compressibly resilient member or latch is compressed to allow the end of the vertical brace to slide over (or passed) the compressibly resilient member or latch and into the bottom pocket (or top pocket) such that the vertical brace is substantially straight (i.e. not on an angle). Once the end of the vertical brace slides completely over the compressibly resilient member or latch, the compressibly resilient member or latch returns to its natural position, thereby forming one wall (or a partial wall) of the bottom pocket (or top pocket) and securely retaining the end of the vertical brace within the bottom pocket (or top pocket).
Referring to
As the brace 516 is moved along the channel 503, the brace 516 forces the latch 510, 512 to compress allowing the brace 516 to pass into the pocket 514. The compressed latch 510, 512 then decompresses back to original location thereby extending into the channel and preventing the brace 516 from being removed from the pocket 514. It should be appreciated that the latches 510, 512 are configured so that they only compress when the brace is located outside of the pocket 514 and moved toward the pocket 514. For example, referring again to
Referring to
As the brace 616 is moved along the channel 602, the brace 616 slides along the channel base 608 and forces the latch 610, 612 to compress allowing the brace 616 to pass over the latch 610, 612 and into the pocket 614. The latch 610, 612 then decompresses such that the brace 616 is prevented from moving along the channel 602 and capturing the brace 616 within the pocket 614 and preventing the brace 616 from being removed from the pocket 614. It should be appreciated that the latches 610, 612 are configured so that they only compress when the brace is outside of the pocket 614 and moved toward the pocket 614. For example, in one embodiment as shown in
It should be further appreciated that in an additional embodiment, the brace 516, 616 may be expandable/retractable as discussed hereinabove with regards to the internal supports 224, 226, 234 where a dowel or pin 525, 625 may be used to keep the brace 516, 616 expanded. Accordingly, in this case one end of the brace 516, 616 may be located in a top pocket (or bottom pocket) and telescopingly expanded until the other end of the brace 516, 616 is located in the bottom pocket (or top pocket), where a dowel or pin would be used to lock the brace in the expanded configuration (See
In accordance with an additional embodiment of the invention, referring to
It should be further appreciated that the function of the plurality of latches 510, 512, 610, 612 may also be accomplished by the natural flex of the plastic material used to construct the channel 502, 602. Moreover, the internal supports 224, 226, 234 and/or braces 516, 616 may be constructed from any material suitable to the desired end purpose, such as a fiberglass, metal, a composite material and/or a thermoplastic material, such as polypropylene or high density polyethylene or non-thermoplastic material. Moreover, the internal supports 224, 226, 234 and/or braces 516, 616 may be sized as desired or for a particularly sized tank. For example, in one embodiment the internal supports 224, 226, 234 and/or braces 516, 616 may be square shaped with a width W of about 1 inch, a depth D of about 1 inch and a length that is dependent of the size of the tank. Additionally, in another embodiment the internal supports 224, 226, 234 and/or braces 516, 616 may be square shaped with a width W of about 2 inches, a depth D of about 2 inches and a length that is dependent of the size of the septic tank. In still yet another embodiment, the internal supports 224, 226, 234 and/or braces 516, 616 may be rectangular shaped with a width W of about 2 inches, a depth D of about 1 inch and a length that is dependent of the size of the septic tank.
Additionally, the septic tank may be made of a thermoplastic such as a polypropylene or high density polyethylene. In generality of the invention, the septic tank may be made a multi-piece construction (i.e. two half tanks) or a single-piece construction and/or by means other than injection molding and they may be made of a non-thermoplastic resin, as well.
While the invention has been described with reference to an exemplary embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Moreover, the embodiments or parts of the embodiments may be combined in whole or in part without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.
This application claims priority to and benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/666,496, filed Jun. 29, 2012, the contents of which are incorporated by reference herein in its entirety.
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Number | Date | Country | |
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61666496 | Jun 2012 | US |