GB2196372A - Fuel tank with recess in flat top - Google Patents

Abstract

A fuel tank comprises a generally rectangular casing 10 which has an external recess 9 formed in one of its major surfaces, the remainder 17 of said one major surface being substantially flat so as to be usable as a support surface when the tank is laid with its ends 12, 21 and narrower sides 18, 19 upright. At least one orifice is formed in the base of the recess and is adapted to receive a fitting such as a closure cap, or a pipe fitting for connecting the interior of the tank into a fuel system, or a level sensor. The depth of the recess is sufficient for the fitting not to project through the plane (A Fig. 3) of the support surface when it is fitted to the orifice. <IMAGE>

Description

SPECIFICATION Fuel tank This invention relates to fuel tanks, and more particularly, although not exclusively, to a portable fuel tank which comprises a generally rectangular substantially rigid casing.

Such portable fuel tanks are usually provided with a handle at one end so that they are carried with their longer faces upright. On the other hand they are often laid with their ends and narrower sides upright and that is especially so when they are used as auxiliary fuel tanks in marine craft. Indeed they may be provided with external recesses which are adapted to cooperate with corresponding projections formed on or by structure of the craft. The flat upper surface of such a tank has been found to be a usable support surface on which various items can be stowed when the tank is so laid.

An object of this invention is to provide an improved fuel tank which is provided with an orifice, for example for filling and/or dispensing, in one of its side surfaces.

According to this invention there is provided a fuel tank comprising a generally rectangular substantially rigid casing which has an external recess formed in one of its major surfaces, the remainder of said one major surface being substantially flat so as to be usable as a support surface when the tank is laid with its ends and narrower sides upright, there being an orifice which is formed in the base of the recess and which is adapted to receive a fitting, wherein the depth of the recess is sufficient for the fitting not to project through the plane of said substantially flat support surface when it is fitted to the orifice.

Preferably the area of said substantially flat support surface is at least half the greater cross-sectional area of the interior of the tank.

The recess is preferably shaped so as to have sides partially surrounding the orifice. Conveniently the substantially flat support surface includes two projecting finger portions which extend on either side of the orifice so that the orifice is substantially surrounded by sides of the recess.

The orifice may be located generally centrally of the casing, transversely and/or longitudinally thereof.

The tank may have a second orifice which is formed in the base of the recess and which is adapted to receive a second fitting, wherein the depth of the recess is sufficient for the second fitting not to project through the plane of said substantially flat support surface when it is fitted to the second orifice.

The or each orifice fitting may be a pipe fitting for connecting the interior of the tank into a fuel system, or a closure cap, or another fitting such as a level sensor for providing an indication of the level of fuel in the tank.

Arranging for the depth of the external recess in which the orifice is formed to be sufficient for the plane substantially flat support surface to pass over the fitting when the latter is fitted has the additional advantage that any resistance to discharge of fuel from the tank due to creation of a partial vacuum in the space above the level of fuel within the tank when fuel is withdrawn is minimised because the volume of that space is larger than it would be if the depth of the external recess was not so great, or if the recess was nonexistent.

One form of portable auxiliary fuel tank in which this invention is embodied is now described by way of example with reference to the accompanying drawings, of which: Figure 1 is a perspective view of the tank showing the handle and two orifices, with a level sensor for one orifice and a pipe fitting for the other orifice removed but shown to one side of the tank; Figure 2 is a perspective view of the tank from the opposite side showing external locating recesses; and Figure 3 is a longitudinal sectional elevation taken midway, transversely, of the tank.

The drawings show a generally rectangular portable fuel tank which is designed for use as an auxiliary fuel tank on marine craft. The tank comprises a hollow casing 10 which is formed of a plastics material having a high molecular weight, such as high density polyethylene by blow-moulding.

Figure 1 shows that the casing 10 is formed with an integral bar handle 11 at one, 12, of its ends. One of the larger, or major, side surfaces is stepped to form a recess 9 which extends from the step 14 to the end 12. The step 14 defines a bight which surrounds a generally upwardly facing orifice which is formed in the generally flat surface of the base 13 of the recess 9. Thus the orifice is substantially surrounded, and therefore protected, by sides of the recess which are constituted by the step 14. An integral cylindrical boss 15 extends outwardly from the base 13 of the recess 9 and surrounds the orifice. A screw-thread is formed on the outer surface of the boss 15 whereby the latter is adapted to receive a pipe fitting.The pipe fitting comprises a fuel outlet pipe 30 and an air breather pipe 31 (constituting means for venting the interior of the tank to avoid creation of a partial vacuum as fuel is used or to release excess pressure due to thermal expansion). The pipes 30 and 31 are formed with enlarged end sections 32, 33 for connection as required to further pipes, pipe 30 being connected to the engine fuel system of the marine craft. Both pipes 30, 31 are secured in holes in a circular disc 35 which sits, in use, on the top of the boss 15. An annular cap 40 with an internal screw thread corres- ponding to that on the boss 15 threadedly engages the boss and clamps the disc 35 with the pipes 30, 31 to the boss through the interposition of a resilient sealing ring 41.To provide a means for locating the disc 35 with respect to the boss 15, an annular locating ring 36 arranged to slide within the boss is secured to the disc 35. The ring 36 is only shown in Figure 1 for schematic purposes.

Typically, the pipes 30 and 31, disc 35 and ring 36 would be metallic and secured together by welding.

A second generally upwardly facing orifice is formed in the base 13 of the recess 9 between the boss 15 and the handle 11. This orifice is surrounded by a second boss 43 of plastic welded to the casing 10 and formed with an external thread for engagement by a second annular cap 44. This second orifice is for mounting a level sensor 46, known per se, to the casing for providing a visual indication of the level of the fuel in the tank. The level sensor 46 comprises five translucent probes 47 extending downwardly from an indicator disc 48 to various depths in the tank. The cap 44 clamps the disc 48 with the probes 47 to the boss 43 through the inter-position of a sealing disc 49.It will be appreciated that the ends of the probes in the indicator disc 48 will appear from above (through the sealing disc 49) a colour according to whether or not the lower ends of the probes are immersed in fuel, and thereby give an indication of the level of fuel in the tank.

As an alternative to either or both of the bosses 15, 43, either or both of the orifices may be tapped with an internal thread so as to receive an appropriate fitting.

Both of the orifices are located midway across the casing and the first orifice is generally central longitudinaily.

The remainder 17 of the stepped major side surface is flat. Its area is at least half the greater cross-sectional area of the interior of the casing 10, the greater cross-sectional area being that contained within narrower sides 18 and 19 and the ends 12 and 21 of the casing 10. The bulk of the flat remainder surface 17 extends from the other end 21 that is remote from the handle 11 to the nearest part of the bight that is formed by the step 14, the flat remainder surface 17 also including two finger portions 22 and 23 which extend towards the end 12, one on either side of the boss 15.

The depth of the step 14 is such that the plane A of the flat remainder portion 17 extends over the caps 40, 44 and the pipes 30, 31 when these fittings are fitted onto the bosses 15 and 43 as shown in Figure 3.

Hence anything placed on the flat remainder surface 17, which serves as a support surface on which it is convenient to store various items, can project over the external recess 13 without fouling any of the fittings. It will also be apparent that two or more tanks with fittings attached could be stacked one upon another, again without fouling the fittings.

Figure 2 shows that the other major side surface 24 is formed with a transverse recess 25 which is designed to receive a correspondingly-shaped projecting portion of the structure of the marine craft so that the tank is located relative to the marine craft when stowed therein with the other side surface 24 resting on the structure of the craft and with the ends 12 and 21 and the two narrower sides 18 and 19 upright. The tank is stable when so supported at sea because of its relatively flat form.

The casing is also shown in Figure 2 as being formed with a bottom recess 26 to engage or clear a corresponding abutment of the marine craft structure but in cases where no such abutment is present this recess may be omitted to increase the capacity of the tank.

It will be understood that the narrow sides 18 and 19 and the major sides 13 and 17, and 24 are upright when the tank is carried by its handle 11. In this orientation, the tank can be rested on feet portions 28 of the casing. To refill the tank when its fuel contents have been used, the pipe fitting (30, 31, 35, 36, 40, 41) would typically be removed and replaced by a closure cap similar to cap 40 but having a blank upper surface whereby to close the first orifice, and the tank would then be carried by its handle to a filling point where the closure cap would be removed to allow refilling through the first orifice. The closure cap would then be replaced and the tank transported back to its location in the craft where the closure cap would be replaced by the pipe fitting as shown.

The tank shown might have a typical capacity of 20 or 25 litres.

Claims (7)

1. A fuel tank comprising a generally rectangular substantially rigid casing which has an external recess formed in one of its major surfaces, the remainder of said one major surface being substantially flat so as to be usable as a support surface when the tank is laid with its ends and narrower sides upright, there being an orifice which is formed in the base of the recess and which is adapted to receive a fitting, wherein the depth of the recess is sufficient for the fitting not to project through the plane of said substantially flat support surface when it is fitted to the orifice.

2. A fuel tank as claimed in Claim 1 wherein the area of said substantially flat support surface is at least half the greater crosssectional area of the interior of the tank.

3. A fuel tank as claimed in either Claim 1 or Claim 2 wherein the recess is shaped so as to have sides partially surrounding the orifice.

4. A fuel tank as claimed in Claim 3 wherein the substantially flat support surface includes two projecting finger portions which extend on either side of the orifice so that the orifice is substantially surrounded by sides of the recess.

5. A fuel tank as claimed in any preceding claim wherein the orifice is located generally centrally of the casing, transversely and/or longitudinally thereof.

6. A fuel tank as claimed in any preceding claim further comprising a second orifice which is formed in the base of the recess and which is adapted to receive a second fitting, wherein the depth of the recess is sufficient for the second fitting not to project through the plane of said substantially flat support surface when it is fitted to the second orifice.

7. A fuel tank substantially as hereinbefore described with reference to and as shown in the accompanying drawings.