GB2087369A

GB2087369A - Fuel tank

Info

Publication number: GB2087369A
Application number: GB8036699A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-11-14
Filing date: 1980-11-14
Publication date: 1982-05-26

Abstract

A tank, which may be for fuel, includes means for ensuring that an air space (17) always remains at the top of the tank after filling. The means may comprise a curved inlet pipe (5) provided with an air bleed hole (13), which extends into the tank (1) from the filler opening and which forms an airtight seal with the lip (9) of the opening. <IMAGE>

Description

SPECIFICATION Fuel tank This invention relates to tanks for storing liquids, and in particular to fuel tanks for motor vehicles etc.

It is common for fuel tanks for motor vehicles to be filled to the level of the filler opening, despite advice to the contrary from motor vehicle manufacturers. A consequence is that when the vehicle is moved, or the surrounding temperature increases, large amounts of fuel may be lost through the filler opening.

The present invention provides means whereby overfilling of tanks, even deliberate overfilling, may be prevented.

According to the present invention there is provided a tank for liquids, comprising a body portion provided with a filler opening, and an inlet pipe extending into the body portion and being sealingly connected to the filler opening, the arrangement being such that when sufficient liquid is present in the tank, the surface of the liquid defines the lower boundary of an airtight space.

The inlet pipe may be provided with one or more air bleed holes so that the tank may be filled to a level above the level of the inner end of the inlet pipe.

Preferably, the inlet pipe is curved and terminates in the vicinity of a wall of the tank at a height not more than two pipe diameters below the maximum level of liquid in the tank.

The tank may be used for storing fuel, for example in motor vehicles and boats.

Also provided by the present invention is a pipe for insertion into the filler opening of a tank, said pipe having associated therewith means for sealably connecting the pipe to the filler opening and thereby providing an arrangement such that when sufficient liquid is present in the tank, the surface of the liquid defines the lower boundary of an air-tight space.

The present invention is now described by way of example, with reference to the accompanying drawing, which is a schematic section through a fuel tank.

Referring to the drawing, a tank comprises a body portion 1, provided with a filler neck 3. Lying concentrically within the filler neck is an inlet pipe 5 which extends arcuately into the body portion, terminating in the vicinity of a wall of the body portion and at a height which is preferably less than two pipe diameters below the maximum desired level of fuel in the tank.

It is, of course, important that the body portion 1 and the inlet pipe 5 are made of materials which are resistant to corrosion by the liquid which is to be stored in the tank. In the case where the tank is to be used for petrol, for example, the body portion and inlet pipe are preferably made of steei.

The outer end 7 of the inlet pipe is in the form of a flange which is seated on the lip 9 of the filler neck 3. A ring 11, which may be made of neoprene, is provided around the inlet pipe 5 to ensure an air-tight seal between the outer surface of the inlet pipe and the inner surface of the filler neck 3.

The inlet pipe is provided with an air bleed hole 1 3 at the level which is desired to be the maximum level of fuel in the tank.

In use, fuel is introduced into the tank through the inlet pipe 5. Even after the level has risen to cover the inner end 1 5 of the inlet pipe 5, displaced air continues to be vented by means of the air bleed hole 1 3.

However, when the level of fuel in the tank is sufficiently high to cover the air bleed hole, an air-tight space 1 7 is created. Should the tank continue to be filled, the additional fuel fills only the inlet pipe 5 rather than the body portion 1. This indicates to the user that the tank is filled to the maximum level.

After filling, the inlet pipe is closed by a conventional filler cap, which must, of course, be vented to allow air to replace fuel as it is consumed.

Small movements of the filled tank and its contents will uncover the air bleed hole 13, so allowing air from the space 1 7 to escape into the inlet pipe 5 and permitting the fuel trapped in the upper portion of the inlet pipe to run into the body portion 1.

Should the fuel become heated, the expansion of air and fuel vapour in the air space 1 7 will force a certain amount of fuel back up the inlet pipe. As the level of fuel in the body portion 1 is lowered correspondingly, the air bleed hole 1 3 is again uncovered, allowing escape of air up the inlet pipe.

When the tank is rolled, or a vehicle containing the tank is cornered, only a small amount of fuel can be lost, owing to the positioning of the inner end 1 5 of the inlet pipe relative to the maximum level of fuel. As fuel is displaced towards the filler neck 3, the end 1 5 of the inlet pipe soon becomes uncovered. The loss of fuel is therefore limited to the contents of the inlet pipe.

It is, of course, not necessary for the performance of the invention to provide an air bleed hole in the inlet pipe. The same effect would be obtained with an inlet pipe which terminates at the same height as the air bleed hole.

It is, however, found that an inlet pipe of the form shown in the drawing results in a smoother filling operation as a result of the reduced turbulence in the vicinity of the air bleed hole 1 3.

The present invention is applicable to the building of new fuel tanks or to conversion of old fuel tanks. In the latter case, all that is required is to insert an inlet pipe through the filler neck of the tank and to effect an air-tight seal between the inlet pipe and the filler opening of the tank. This seal may be in the form of a neoprene ring, such as that in the illustrated embodiment, or it may be of any other form. For example, it would be possible to provide a sealing gasket or even an adhesive between the lip 9 of the filler neck 3 and the flange 7 of the inlet pipe.

The invention therefore provides in one of its aspects inexpensive means for modifying existing tanks for liquids so as to effect considerable savings in liquid lost through spillage. This application of the invention could be of great value, particularly to the owners of large fleets of vehicles who would thus be able to derive the benefits of the invention without the cost incurred in a complete replacement of the vehicles' fuel tanks.

Claims

1. A tank for liquids, comprising a body portion provided with a filler opening, and an inlet pipe extending into the body portion and being sealingly connected to the filler opening, the arrangement being such that when sufficient liquid is present in the tank, the surface of the liquid defines the lower boundary of an airtight space.

2. A tank according to claim 1, wherein the inlet pipe is provided with one or more air bleed apertures.

3. A tank according to claim 1 or claim 2, wherein the inlet pipe is curved.

4. A tank according to any preceding claim, wherein the inlet pipe terminates at a height which is not more than two pipe diameters below the maximum level of liquid in the tank.

5. A tank according to any preceding claim, wherein the filler opening is disposed at one end of a filler neck, the inlet pipe extends into the body portion through the filler neck, and wherein the inlet pipe is sealingly connected to the filler opening by a resilient sealing ring surrounding the inlet pipe and abutting the inner surface of the filler neck.

6. A tank according to claim 5 wherein the sealing ring is made of neoprene.

7. A fuel tank substantially as hereinbefore described with reference to the drawing.

8. A pipe for insertion into the filler opening of a tank to form therewith a tank according to any preceding claim, the pipe having associated therewith means for sealably connecting the pipe to the filler opening.