GB2208643A

GB2208643A - Liquid-carrying tubes

Info

Publication number: GB2208643A
Application number: GB8818769A
Authority: GB
Inventors: Richard Barton
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-08-17
Filing date: 1988-08-08
Publication date: 1989-04-12
Anticipated expiration: 2008-08-08
Also published as: GB2208643B; GB8818769D0; GB8719411D0

Abstract

A tube (3a) for the passage of liquid such as derv into a tank comprises a grill (5) positioned within the tube. The grill extends throughout the cross-section of the tube, and has a number of apertures (9). The sizes of the apertures are such that when liquids are fed through the tube at working pressures they are emitted from the grill in the form of jets (11). This reduces the tendency of the liquid to foam or atomise as it passes through thr grill, and the grill prevents the passage of foreign bodies through the tube. The radial dimension of an aperture may be 4mm. <IMAGE>

Description

IMPROVEMENTS RELATING TO LIQUID CARRYING TUBES I have previously designed and sold an anti-syphon fuel guard for mounting within the inlet or outlet tubes to storage vessels. This guard comprises a grill filling the cross-section of the tube. The grill allows liquids such as fuel to pass through the tube but the presence of the grill cross members is intended to prevent tubes or hoses from being inserted into the storage vessel for the purposes of syphoning or pumping the liquid out of the storage vessel.

One of the problems with these known grills is that the apertures are relatively large and skilled people can insert hoses through the grill. One method for preventing this would be to replace the grill with a wire mesh or the like but this leads to particular problems with liquids such as Derv which foam or atomise when discharged through the wire mesh. This is further aggravated when there is air already in the storage vessel which is being filled and which is displaced via the same opening.

In accordance with one aspect of the present invention, I provide a tube for the passage of liquid; and a grill positioned within the tube and extending throughout the cross-section of the tube, the grill having a number of apertures of a size such that liquids fed through the tube at working pressures are caused to be emitted from the grill in the form of jets.

I have discovered that by causing the liquid to form jets as it is emitted from the grill, this tends to form a vortex which carries any extraneous air in the vicinity away from the grill and reduces the tendency of the liquid to foam or atomise. The grill has the additional advantage that the apertures needed to cause the formation of jets are smaller than the apertures used in the conventional anti-syphon guards and thus also substantially prevent the possibilit of syphon or pump hoses being inserted through the grill.

Although the grill apertures may be of any suitable shape and size to generate jets, in the preferred example the grill apertures extend in a circumferential direction about the centre of the grill. Preferably the apertures are spaced apart in one or both of the radial and circumferential directions about the centre of the grill.

The tube which would typically have a circular cross-section may form an integral part of a storage vessel (such as the inlet or outlet tube) or could be a separate item which can be fixed to an inlet or outlet aperture of a storage vessel. Furthermore, the tube could be rigid or flexible.

Preferably, the grill also has a central aperture.

I also provide, in accordance with a second aspect of the present invention, a storage vessel having a combination of a tube and grill according to the one aspect of the present invention and at least one vent for air displaced from the storage vessel as it is filled through the tube with liquid. The at least one vent may be provided in or on the vessel itself separate from the tube but could also be provided in the grill.

It is important that the vent or vents communicate with an escape path of dimensions sufficient to avoid back pressures.

An example of the invention will now be described with reference to the accompanying drawings, in which: Figures la-ld are schematic drawings of a part of a storage vessel showing four examples of the invention; and Figure 2 is a plan of one example of a grill.

Figure la illustrates part of a storage vessel 1 such as a fuel tank. The storage vessel 1 may be located on boats, ships, aircraft, mobile or fixed plant, agricultural equipment or self propelled vehicles or could be provided as a self-contained fixed/static structure. The storage vessel 1 has a vertically opening inlet aperture 2 communicating with an inlet tube 3 integrally formed with the vessel 1. An inner tube 3a is supported within the inlet tube 3 by bolts 10, with a cylindrical air vent 4 extending between the tubes 3, 3a.

An anti-syphonl antifoaming grill 5 is provided within the tube 3a.

The grill 5 is shown in more detail in Figure 2 and comprises a series of concentric, radially spaced rings 6 coupled together in this example by six equl-angularly circumferentially spaced and radially outwardly extending ribs 7. In other examples a different number of ribs could be used. The grill has a central aperture 8.

Typically, the grill 5 may be formed from a steel plate which has been cut using a laser although other means could be used. The outer ends of the ribs 7 are welded to the inner surface of the metal inlet tube 3.

In use, a liquid such as Derv is supplied under pressure through the aperture 2 and into the inlet tube 3. The liquid will then pass through the apertures 9 defined between the rings 6 of the grill and between the grill and the tube 3. The size of these apertures has been chosen so that the liquid will form jets on the downstream side of the grill 5 as indicated by arrows 11 in Figure la. The liquid jets then pass into the storage vessel 1. Air displaced by this entry of liquid is vented through the air vent 4.

It will be noted in Figure 2 that the rings 6 are positioned relatively closely together defining narrow apertures 9 through which it would be very difficult to pass hoses or pipes for the purposes of phoning or pumping the liquid out of the vessel 1 through the tube 3.

In one eagle, the apertures 9 have a dimension in the radial direction of about 4mm.

Figure lb illustrates a second example in which air vents 4 are provided by apertures 12 in the side of the inner tube 3a, the apertures 12 being situated just below the main wall of the storage vessel 1. In this example, the inner tube 3a fits closely within the inlet tube 3.

In the Figure Ic example, the air vent 4 is provided separatel from the inlet system.

In Figure ld, air is vented via separate tubes 20,21 which are connected by a rubber hose '3. In this example the inlet tube comprises two sections 3b,3c. The tubes 20,21 communicate with the two sections 3b,3c respectively of the inlet tube via apertures 14, 15 positioned on opposite sides of the inner tube 3a. The inner tube 3a with the filter 5 is held between the two sections 3b,3c of the inlet tube b a second rubber hose 22.

Claims

1. A tube for the passage of liquid; and a grill positioned within the tube and extending throughout the cross section of the tube, the grill having a number of apertures of a size such that liquids fed through the tube at working pressures are caused to be emitted from the grill in the form of jets.

2. A tube according to claim 1, wherein the apertures extend in a circumferential direction about the centre of the grill.

3. A tube according to claim 1 or claim 2, wherein the apertures are spaced apart in one or both of the radial and circumferential directions about the centre of the grill.

4. A tube according to any of the preceding claims, wherein the grill has a central aperture.

5. A tube according to any of the preceding claims, wherein the tube is rigid.

6. A storage vessel comprising a tube and a grill according to any of the preceding claims; and further comprising at least one vent for air displaced from the storage vessel as it is filled through the tube with a liquid.

7. A storage vessel according to claim 6, wherein the at least one vent is in the vessel and is separate from the tube.

8. A storage vessel according to claim 6, or claim 7 wherein the at least one vent forms part of the grill.

9. A storage vessel according to any of claims 6 to 8, wherein the at least one vent is sufficient to avoid back pressures.