Abstract
A tank for transporting, storing, and dispensing viscous materials is disclosed having a cylindrical body, and spherical ends. The tank further comprises an ellipsoidal follower device used to force the viscous material through the tank, the follower device having an upper half, and lower half, and a centerline. A plurality of stabilizing fins are rigidly connected to the ellipsoidal follower device at the centerline and extending axially along the tank's inner wall, the stabilizing fins disposed between a periphery of the ellipsoidal follower device and an inner wall of the cylindrical body. The fins serve as an anti-tipping device to maintain the follower in the proper orientation even upon rested in a horizontal position.
Claims
1. A tank for transporting, storing, and dispensing viscous materials having a cylindrical body, and spherical ends, the tank further comprising: an ellipsoidal follower device having an upper half, and lower half, and a centerline; a plurality of stabilizing fins rigidly connected to the ellipsoidal follower device at the centerline and extending axially, the stabilizing fins disposed between a periphery of the ellipsoidal follower device and an inner wall of the cylindrical body; whereby a length of the stabilizing fins is equal to a height of the upper half and quarter depth of the lower half of the ellipsoidal follower device.
2. The tank of claim 1, wherein the stabilizing fins number four and are equally spaced around a perimeter of the ellipsoidal follower device.
3. The tank of claim 2, wherein the stabilizing fins have a depth that is four times less than a width.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view, partially in shadow, of a prior art system;
[0014] FIG. 2 is a side view, partially in shadow, of a prior art system;
[0015] FIG. 3 is a side view, partially in shadow, of the present invention;
[0016] FIG. 4 is a top view of the follower device of FIG. 3;
[0017] FIG. 5 is an enlarged, side view of the follower device of FIG. 3; and
[0018] FIG. 6 is a bottom view of the follower device of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] FIG. 3 illustrates a tank 10 designed to store, transport, and dispense viscous materials, having a tank body 100 that rests upon a stand or base 102. The tank has semi-spherical upper and lower ends 104,106 that are joined to the cylindrical body 100 by annular rings 108. A material ingress/egress port 110 is located at the bottom of the tank 10, and a cap 112 and pressure valve 114 are located on the spherical upper end 104.
[0020] FIG. 3 further illustrates an improved ellipsoidal follower device in a grease tank 10 having stabilizing fins 20 that extend longitudinally away from a centerline joining the upper body 30 from the lower body 40 of the follower device 50. The stabilizing fins 20 extend both above and below the centerline 25, although in a preferred embodiment they extend substantially to a height of the upper body 30, but extend only one fourth of that distance below the centerline 25. The presence of the stabilizing fins 20 prevent the follower device 50 from tipping when the tank is laid sideways because the fins 20 keep in contact with the inside wall 60 of the tank 10 and maintain a parallel relationship with the inside wall at all times, no matter what position or angle the tank 10 is placed. There is a critical length L of the stabilizing fin 20 that is related to the distance between the diameter D.sub.D of the follower device 50 and the diameter D.sub.T of the tank 10, whereby the angle that the follower device 50 may lean given the tolerance before it will not return to its original position is a function of the weight of the follower device 50, the number of fins 20, the surface roughness R.sub.S of the inner wall 60 of the tank 10, and the internal pressure P.sub.i in the tank. However, it has been found that in most cases a length L that extends to the height of the upper body 30 and twenty five percent (25%) of the depth of the lower body 40 will preserve the orientation of the follower device 50 in virtually all cases and prevent the condition where tipping leads to a non-operational condition.
[0021] As shown in FIGS. 5 and 6, the stabilizing fins 20 are thin blade like members (i.e., a depth four times less than a width) that do not interfere with the follower device's function of forcing the material through the tank 10, and further operate as spacers that keep the follower device 50 centered within the tank 10 to protect the tank from marring and damage due to contact with the follower device. The number of stabilizing fins 20 can be increased from four to further stabilize the follower device, although it has been found that four will meet the conditions for stability required in most applications. The fins 20 can be attached by welding in a preferred embodiment, but a small bracket can also be used to fasten the fins 20 to the follower device's centerline 25. It is important that the attachment of the stabilizing fins 20 result in a rigid connection, as any flexure can lead back to the original problem where the follower device tilts excessively and cannot return to its intended orientation. For that reason, the connection of the fins 20 to the follower device 50 must maintain the fins 20 in a tangential relationship with sufficient rigidity to resist bending. To this end, the thickness of the fins must also be of a value to prevent appreciable bending as the tank is laid horizontal, to prevent the follower device from tilting or tipping from the parallel relationship with the longitudinal axis of the tank.
[0022] While a preferred embodiment has been described and depicted in the drawings, it is to be understood that the scope of the present invention is not to be limited to the description of the preferred embodiments or the depictions in the drawings. One of ordinary skill in the art would readily appreciate that modifications and substitutions would be available to such described embodiments, and the invention in intended to incorporate and include all such modifications and substitutions. Accordingly, nothing in this specification should be taken as limiting the invention to anything characterized herein unless expressly stated.
