Abstract:
A pump and tank lid assembly. The pump is of a low-profile, lightweight design to enable it to cooperate with the lid so that a relatively thin-walled tank can support its weight. In addition, the low-profile design allows the pump to remain attached to the top of the tank, even during shipping and stacking of the tanks. Projections formed either in the tank or on a frame that surrounds the tank extend beyond the dimensions of the pump. The projections allow stacking of fluid material containing tanks so that during tank stacking, adequate clearance is formed between the top of the pump in a lower tank and the bottom of an upper tank.

Description:
[0001]    This application claims the benefit of the filing date of U.S. Provisional Application No. 60/787,075, filed Mar. 29, 2006. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates generally to a pump mounted to the lid of a tank, and more particularly to a low profile pump that cooperates with a tank lid to allow withdrawal of a fluid material in a tank from the top of the tank, as well as the ability to stack tanks without the removal of the pump. 
         [0003]    It is common practice today to ship fluid materials (such as flowable or granular solids, liquids or the like) in 120 to 200 gallon shipping containers known as totes, mini-bulk tanks, or intermediary bulk containers (IBCs), collectively referred to as tanks or containers. The typical tank will have a filling port or lid on top (usually an eight-inch diameter opening), and a two-inch bunghole for mounting apparatus and/or a bottom dispensing port for draining. A pump is typically mounted to either the bunghole or the filling port, and in a typical application, these pumps are used to empty tanks in the field. A significant amount of agricultural liquid-storage containers utilize top-mounted pumps to transport fertilizers, insecticides or the like. Such tanks can also be used in the industrial market to transport other bulk fluids such as soap, oils, bleach, ink or the like. 
         [0004]    Recently, these tanks have been equipped with an external frame; such “bird cage” tank styles provide enhance tank rigidity that facilitates tanks support and shipping. Unfortunately, this style of tank makes it difficult to accept top-mounted pumps. In another recent development, inexpensive and lightweight tanks with thin flexible plastic walls have been introduced to the market. The construction of such tanks makes it difficult and expensive to mount or install a top connected pumping system. In one typical configuration, a pump is mounted on the bottom discharge valve to empty the contained fluid. Bottom withdraw pumps have problems due to their large size, limited floor space and risk of leaking. In addition, having to disconnect the pump and its ancillary equipment in order to stack or move tanks presents a significant inconvenience to the user or operator. 
         [0005]    An alternative is to mount the pumps using a modified tank lid. In one approach, a hole can be cut into the lid, where the pump is held in place on top of the tank with a jam nut or related locking mechanism. This method is limited to tanks only with large enough lids capable of fitting the flange on the pump housing. A second approach is to place a port into the lid (similar to the aforementioned bunghole) and mount the pump using standard piping methods. Both of these mounting approaches have potential problems. First, a high pump profile above the tank frame increases the volume of the tank, thereby reducing stacking efficiency. Second, the mounting allows for an increased number of potential leak paths. Third, the tank must have a large enough lid to accept the pump flange. 
         [0006]    In yet another alternative configuration, multi-walled tanks have been employed, especially for use with tanks for hazardous material storage, transport and dispensing. In such construction, an outer tank can be made to conformally fit around an inner tank to protect the latter from, inter alia, shipping and handling damage. Such features, while useful for their intended purpose, significantly add to the cost, weight and complexity of the tank, which is disadvantageous for totes, mini-bulk tanks or IBCs, especially when such are configured as containers that can be disposed of after one (or only a few) uses. 
         [0007]    Examples of pumps that may be useable in the aforementioned applications are described in detail in other patents owned by the Assignee of the present invention, including U.S. Pat. Nos. 4,557,669 (describing the pump and working mechanism thereof), 4,570,833 (describing a closed system pumping design), 4,685,592 (describing a closed system that has a rinsing device), 5,450,987 (describing a spring-loaded safety valve located in the discharge valve of the pump, a feature that will be utilized in the present invention), and 5,366,351 (describing an automatic shutoff valve for a pump and motor), all hereby incorporated by reference. 
         [0008]    In another entirely different configuration, a pump assembly may include a flange that is mounted to the tank using a tank lid with a large hole cut out. A disadvantage with such design is that the assembly is heavy, making it difficult for the relatively thin tank walls to support its weight. Another disadvantage is that the pump possesses a relatively tall profile, thereby taking up more space than necessary and impeding tank stacking. What is desired is a pump and lid combination that takes up less weight and volume than conventional approaches. 
       SUMMARY OF THE INVENTION 
       [0009]    These desires are met by the present invention, wherein a pump and a method of operating the pump that incorporates the features discussed below is disclosed. According to a first aspect of the invention, a stackable container assembly is disclosed. The assembly includes a tank for containing a fluid material therein and a pump coupled to the tank. The tank includes a bottom section, top section and intermediate section that together make up a fluid material container. The pump is coupled to the tank at the top section, and is sized and shaped such that the pump can easily fit onto an existing lid mount. More particularly, the pump defines a low-profile form such that it occupies a volume that does not extend beyond dimensions defined by tank structure at the upper end of the tank. Together, the assembly formed by the pump and tank coupled together allows the pump to remain attached to the tank, even during container transport and storage. 
         [0010]    Optionally, the pump has an integral housing which has threads that cooperate with complementary threads formed on the top of the tank. Thus, by simple screwing and unscrewing operations, the pump can be easily mounted and dismounted from the tank. In another particular configuration, the pump and the tank are removably connected to one another through simple mounting means (such as wing nuts or other such fasteners that do not require little or no tool use) such that the pump can be easily detached from the tank. In a more particular form, the pump is connected to the tank through one or more screws that can be engaged or disengaged without the use of tools. Ancillary components used to support pump functions (such as power supplies, fluid material conduit or the like) may be configured such that they either do not extend heightwise beyond the dimensions established by the pump or can be readily separated therefrom. 
         [0011]    In one form, the tank is made up of a plastic material. In a particular option, the intermediate section is made up of numerous lateral walls, where the tank can define, for example, a generally rectangular cross-section. In a particular configuration, the top section is formed as a lid that is selectively attachable to the tank intermediate section. Projections (discussed below) formed into or cooperative with the tank may define a volumetric space that extends above or below the fluid material-containing portions of the tank. These projections (as well as complementary recesses configured to accept such projections) may make up stacking members that may include nesting attributes to promote a more secure connection between stacked tanks. The additional space created by the presence of the projections allows a heightwise clearance distance between the top section of the tank (also referred to as a first tank) and a bottom section of a second tank that can be stacked upon the first tank so that the bottom section of the second tank does not form an interference fit with the pump that is situated on the top of the first tank. For example, the pump coupled to the top section defines a heightwise dimension that is less than the heightwise clearance distance between the first and second staked tanks. 
         [0012]    The assembly may also be equipped with a frame disposed substantially about the tank to increase the tank rigidity. Numerous stacking members may be formed into the upper and lower surfaces of the frame such that upon stacking of one of the frames onto another, surface features formed into the upper surface of the lower one of the stacked frames may cooperatively engage the surface features formed into the lower surface of the upper one of the stacked frames. In configurations where no frames are used, such that stacking is between upper and lower tanks directly, the stacking members may be formed directly into the top and bottom sections of the tank. In this way, when the tank is stacked upon another generally similar tank, the stacking members formed into the top section of the lower tank cooperatively engage the stacking members formed into the bottom section of the upper tank. In either form of such an assembly, the stacking members formed into the bottom section may define substantially downward-projecting legs, while the stacking members formed into the top section comprise a plurality of substantially upward-projecting arms. Shaping, tapering or sizing between the arms and legs may contribute to nesting features that can be exploited to facilitate a secure fit between them. In another configuration, either of the top or bottom section may instead include recesses (rather than projections) formed to allow cooperation between adjacently-placed stacked tanks. For example, a first tank may have upwardly-projecting arms extending from the top section so that when a second tank is stacked onto the first tank, the recesses formed in the bottom section of the second tank and the upward-projecting arms of the top section of the first tank may be nested, thereby reducing the tendency of the two tanks to move laterally relative to one another. 
         [0013]    Such a configuration will make it easy to mount the pump to existing tanks, many of which have a standardized lid with a threaded connection. For example, the connection may be formed from a six inch (or other conveniently-sized) diameter. As stated above, the fluid material-containing part of the tank may be made from a thin-walled plastic tank that may or may not be strengthened by a metal frame to improve lifting, transportation and stacking of the tank. 
         [0014]    In one embodiment, the coupling of the pump and the lid is done in such a way that the pump remains with the lid through the life of the container. The container, while capable of being reused, may be disposable. In such case, the pump needs to be inexpensive enough that it too can be thrown away with the tank and lid. The coupling of the pump to the lid can thus be of a permanent or semi-permanent nature, such that the pump and lid form a single component. A key benefit of having the pump and lid as one component is a low profile which does not rise above the tank&#39;s surrounding frame. This allows the ability of stacking one tank on top of another without having to go through the time-consuming process of removing the pump. This is especially valuable where large numbers of containers are being used or stored in a common location, so that floor storage space is best utilized. 
         [0015]    The pump is configured to be removably attached to a discharge port (which may be in the form of an elbow or related bend), a motor used to turn the pump, and a switch used to turn the pump on and off. This allows safe transporting of the tank while maintaining the original low profile of the pump and lid assembly. One or more particular features may be included in the pump. For example, the pump may have an internal valve that closes upon removal of the discharge elbow. This prevents leaks during transportation, especially for situations where the user does not install a secondary rain lid. The pump may also include an integral venting port and cover; these can be removed to allow air to enter the tank as the fluid is removed during pumping off of the fluid, thereby preventing tank collapse. By keeping the pump and lid assembly lightweight, no secondary support during transportation is required. 
         [0016]    According to another aspect of the invention, a stackable tank is disclosed. The tank includes a fluid container portion, a stacking portion, a lid cooperative with the fluid container portion and a pump coupled to the lid. The stacking portion extends a heightwise clearance distance beyond the fluid container portion, and defines a heightwise dimension that is less than the heightwise clearance distance such that upon stacking of two or more of the tanks, the pump on a lower one of the tanks does not interfere with an adjacent surface on an upper one of the tanks. The stacking portion may be made up of stacking members, such as the aforementioned arms, legs and recesses, all of which can be integrally formed into one or more surfaces of the tank. 
         [0017]    According to another aspect of the invention, a method of stacking fluid material containers is disclosed. The method includes securing a pump to a generally upper surface of one or more fluid material containers, providing a stacking portion to the container such that the stacking portion extends a heightwise clearance distance that is greater than a heightwise dimension defined by the pump, and stacking the containers such that an upper container does not form an interference fit with the pump that is part of a lower container. 
         [0018]    Optionally, stacking members are formed on one or both of upper and lower surfaces of the fluid material containers. In this way, the stacking members from the upper surface of the lower stacked container are substantially complementary with the stacking members from the lower surface of the upper stacked container. By placing the stacking members from the lower one of the stacked containers into cooperative arrangement with the stacking members from the upper one of the stacked containers, a more secure fit between the stacked containers is formed. In a particular form, the stacking members make up the stacking portion of the container. In another particular form, the stacking portion is integrally formed (such as by molding or other approaches that would result in a substantial unitary structure) into its corresponding fluid material container. In another form, a frame can be included to enhance the container. In this way, the stacking portion may be formed as part of the frame, or may be formed as part of the container directly and made to extend beyond the frame. In situations where the stacking members form part of a frame that is attachable to or otherwise structurally cooperative with the tank, such stacking members may also include lateral support in the form of webs, ties or other structure that maintains lateral spacing among the legs, arms or other vertically engaging components of the stacking members. 
         [0019]    Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0020]    The following detailed description of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
           [0021]      FIG. 1  is an elevation view of a pump attached to a tank lid according to the prior art; 
           [0022]      FIG. 2  is an elevation view of an embodiment of the pump and lid assembly of the present invention; 
           [0023]      FIG. 3  is a view of the pump of  FIG. 2 , shown removed from the lid of the tank; 
           [0024]      FIG. 4  shows the pump and lid assembly of  FIG. 2  on top of a tank, with a second tank stacked on top of the first; 
           [0025]      FIG. 5  shows a detail view of the low profile nature of the pump and lid assembly of  FIG. 4 , and how it does not interfere with the lower part of the frame of the second tank; 
           [0026]      FIG. 6  shows various views of the pump and lid assembly of  FIG. 2 , now also showing the inclusion of a motor, switch and discharge port; and 
           [0027]      FIG. 7  shows a pair of tanks according to an aspect of the present invention being stacked on top of one another. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring first to  FIG. 1 , an assembly for a pump  10  connected via lid  20  to the top of a tank  50  according to the prior art is shown. The configuration is such that an aperture or port (not shown) in the top of tank  50  allows fluid communication between the pump  10  and the tank  50 . The pump  10  includes a pumping device (not shown) enclosed in a housing  30  and a motor  40 . Suction elbow  60  connects the pump  10  and lid  20 . A frame  70  can be used to provide structural rigidity to tank  50 . As can be seen, the vertical profile of pump  10  is such that it projects above the top of tank  50  so that if multiple tanks  50  were to be stacked one on top of the other, pump  10  would have to be removed to avoid damage to the pump  10 , lid  20  or both. 
         [0029]    Referring next to  FIGS. 2 through 7 , a pump and lid assembly  100  according to an aspect of the present invention is shown. The assembly  100  includes a pump  110  and lid  120 . In the present disclosure, the terms “lid” and “top” are used interchangeably, and any ambiguity will be resolved by reference to the context in which each term is used. As shown, lid  120  is integrally formed into the uppermost part of tank  150  such that it functions as the top thereof. In such configuration, the tank  150  is of one-piece design, and can be manufactured by methods known in the art, such as blow molding, rotational molding or the like. In another form (not shown), the lid  120  may be separately formed from the remainder of the tank  150  such that the two can be attached (through conventional securing means understood by those skilled in the art). Such a separate construction could be especially compatible with configurations where the pump  110  and lid  120  are connected as part of a unitary structure. In this latter configuration, connection or fastening between the lid  120  and the tank  150  can be established by approaches well-known in the art. 
         [0030]    As shown with particularity in  FIGS. 2 and 3 , a threaded connection  117  between the pump  110  and the lid  120  promotes a secure connection between the two, although it will be appreciated by those skilled in the art that other connection schemes may be used. A pump inlet  111  extends downward from the bottom of pump  110  into tank  150 . By eliminating the elbow  60  and reorienting the pump  110 , as well as placing at least a portion thereof below the top of tank  150 , the overall profile of the assembly  100  can be significantly reduced.  FIG. 3  shows the lid  120  removed for clarity to better show the threaded connection  117  formed as an outer flange of pump  110 . 
         [0031]    Referring next to  FIGS. 4 and 7  in conjunction with  FIG. 2 , one benefit of the tank configuration of the present invention is the ability of the tanks  150  (shown individually as a lower tank  150 A and upper tank  150 B) to be stacked, thereby improving storage and shipping efficiency. As can be seen, the pump  110  is sized to fit with the lid  120  such that the pump  110  has a low vertical profile to avoid interference with the surface of an adjacently stacked tank. In addition, the pump  110  is secured to the lid  120  (such as by the threaded connection  117  discussed above) so that when not pumping the fluid material inside the tank  150 , the pump  110  acts as a cap surrogate to prevent spillage of the fluid material from the tank  150 . By having the pump  110  be top-mounted, leakage and storage problems associated with bottom-mounted pumps are avoided. 
         [0032]    Stacking members  175  can be used to align and stackedly couple lower tank  150 A and upper tank  150 B. Stacking members may be formed as part of frame  170 , or may be formed as a separate components that, like a tray, pallet or related support, may be used to effect the stacking between vertically adjacent tanks  150 A,  150 B. The low-profile nature of the pump  110 , coupled with stacking members  175  formed with downwardly-projecting legs  190  and complementary-shaped arms  180  allow nested cooperation and secure stacking of two or more of the tanks  150 A,  150 B. In the construction depicted in  FIGS. 4 and 7 , as well as partially depicted in  FIG. 5 ), the stacking member  175  is placed above, below or both above and below a tank to which it attaches. Nesting components (such as arms  180  and legs  190 ) are either formed separately from and attachable to the frame  170 , or can be made as a part thereof. When made separately from the frame  170 , the stacking member  175  (and its attendant nesting components) can be formed from a single piece of moldable material, such as a plastic. In a separate construction (not shown), where the stacking members are integrally formed into one or both of tank upper and lower surfaces, the downwardly-projecting legs  190  may extend from a lower surface of an upper tank  150 B and complementary-shaped arms  180  may extend from an upper surface of a lower tank  150 A. In such integral formation, the stacking members and tanks may be made from a plastic-based material. 
         [0033]    In one form, the tank  150  and pump  110  are readily separable from one another such that either or both may be reused. Even in situations where the pump  110  can be removed from the tank  150 , the low profile nature of the assembly  100  is such that the pump  110  can be left in place during shipping to reduce the time and complexity associated with transport of both. In an optional form, the tank  150  and pump  110  can be made of low-cost material and manufacturing methods such that the pump  110  may be integrally-formed with the tank  150  or lid  120 , allowing both to be disposed of upon dispensing of the fluid material contained therein. 
         [0034]    Each tank  150  includes numerous lateral (i.e., side) walls  115 , a lid (or top)  120  and bottom  125 . The lid  120  can be integrally formed such that it forms a continuous upward extension of the side walls  115 . As can be seen, the tanks  150 A,  150 B include the stacking members  175  made up of arms  180  and legs  190 . These projections (i.e., the arms and legs  180 ,  190 ) allow complementary engagement that make up the stacking members  175 , and may be separate components (as shown in  FIGS. 4 and 7 ) or molded into or otherwise formed into the appropriate top or bottom of the tank  150  to allow secure placement of one tank into another in stacked relationship, both as discussed above. The arms and legs  180 ,  190  define a stacking portion that extends a distance beyond (either above or below, depending on the orientation of the tank  150 ) the portion of the tank  150  that contains the fluid material. This extension is of sufficient dimension (such as depth) that the uppermost part of pump  110  does not touch an adjacent surface of upper tank  150 B that is stacked on top of the lower tank  150 A. This is beneficial in that the pump  110  need not be removed from tank  150 A while the tanks  150 A,  150 B are stacked. As can be seen with particularity in  FIGS. 4 and 5 , connecting structure (in the form of webs  172 , discussed below) can be used to provide structural coupling between adjacent arms  180  or legs  190 . 
         [0035]    Referring with particularity to  FIG. 7 , tank  150  is relatively thin-walled, and therefore may include a substantially rectangular frame  170  which can be sized and configured such that it forms with or around the tank  150  to promote structural rigidity of the tank  150 , as well as provide the stacking members  175  and other stacking-enhancement features. In the alternate configuration, the arms  180  and legs  190  of the stacking member  175  may be formed as part of the tank  150 . In the configuration where the stacking members  175  are formed as part of frame, the tank  150  can be made of a more conventional shape, such as rectangular, cylindrical or the like. Although not shown, ridges or related protuberances can be formed in the lateral walls  115 , bottom walls  125  or other parts of tank  150  in order to enhance its rigidity. 
         [0036]    As shown with particularity in  FIG. 4 , a lower tank  150 A and upper tank  150 B are in a stacked arrangement, where pump  110  is placed on top of lower tank  150 A. It can be seen that the low profile nature of pump  110  allows it to fit underneath the lower portion of frame  170 B (that is used to provide rigidity to upper tank  150 B) in such a way that the pump  110  does not come in contact with frame  170 B. This promotes stacking and related transport without having to remove pump  150 . Specifically, connecting structure  172 , shown presently as a thin horizontal web that extends between arms  180  (only a tiny vertical portion of which is seen extending out of the bottom of leg  190  with which it is nested), may form part of the stacking member  175  or frame  170 A or  170 B. 
         [0037]    Referring next to  FIGS. 6A through 6C , various views of the pump  110  and lid  120  connected together as an assembly  100  are shown with removable ancillary pump components, including motor  140 , discharge port  160  and switch  180 . As with the connection of the pump  110  to the lid  120 , these components can be secured to the pump and lid assembly  100  with a small number (for example, two) wing nuts  260  or related fasteners, thereby allowing the removable components to be taken off prior to storage or stacking of tank  150 . In a preferable form, such attachment and removal is a tool-less operation. By having readily-detachable features, the motor  140  and other ancillary components can be reused. The cutaway view of  FIG. 6B  highlights some of the internal mechanisms of the pump  110 , including the pump pistons  210  that are cooperative with outlet valves  220  and inlet valves  230 , bypass valve  240  that dispenses into the tank  150 . A tank vent  250  is shown in  FIG. 6C  to allow vapor to escape, thereby preventing an overpressure in the tank  150 . 
         [0038]    Having described the present invention in detail and by reference to the embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention in the following claims.