GB2069835A

GB2069835A - Foam cannons

Info

Publication number: GB2069835A
Application number: GB7937127A
Authority: GB
Original assignee: STREBOR FIRE PROTECTION Ltd
Current assignee: STREBOR FIRE PROTECTION Ltd
Priority date: 1979-10-25
Filing date: 1979-10-25
Publication date: 1981-09-03
Also published as: GB2069835B

Abstract

A foam cannon comprises a water inlet (12) and a barrel (14), each connected to an enclosure (10). A water nozzle (36), and a foam induction head (38) are mounted on a plate (28) within the enclosure (10). The plato (28) is slidable between a first position, in which the water nozzle (36) is aligned with the water inlet (12) and barrel (14), and a second position in which the foam induction head (38) is aligned with the water inlet (12) and barrel (14). In the first position, the cannon acts as a water cannon: water from the inlet (12) passes through the nozzle (36) and out through the barrel (14). In the second position the foam induction head (38) draws in foam compound via pipes (40, 42) and air is drawn in through holes (24), which are uncovered by movement of a slide (44) as the plate (28) is moved to the second position. The water, foam compound and air mix to form foam, whereby the cannon acts as a foam cannon in the second position. Thus, simply by moving the plate (28), manually (by means of a handle (32)) and/or by remote control, the cannon can dispense either water or foam. <IMAGE>

Description

SPECIFICATION Foam cannons This invention relates to foam cannons.

Foam cannons (also known as branchpipes) are used to produce foam for fire-fighting. In a typical foam cannon, water is fed under pressure through the cannon to a foam induction head in which the flow of water induces a foam compound to flow into the water stream. Air is also induced to flow via air intakes into the water stream. The three constituents (water, foam compound and air) are mixed and expand, forming bubbles which float and blanket the surface of a burning substance, for instance an inflammable liquid such as oil.

It is often desirable for a foam cannon also to act as a water cannon. One known form of cannon usable either as a foam cannon or as a water cannon incorporates separate foam and water barrels or pipes and an arrangement of shut-off valves to enable switching between the two. The use of dual pipes and shut-off valves renders the equipment expensive and produces a high weight loading on a head of a water inlet pipe. Further, it is necessary to introduce bends into the system, which adversely affects fluid flow. In another known dual-purpose cannon the need to have dual pipes has been overcome by the expedient of dividing the cannon at its centre to separate foam making and water sections thereof. In this other known proposal, it is necessary to employ shut-off and diversion valves, again at the cost of expense and weight.Furthermore, the division of the cannon at its centre is undesirable in that operation of the valves to accomplish this can only be effected manually, whereby the equipment can only offer the dual function when it is readily accessible.

According to the present invention there is provided a foam cannon comprising a water inlet, a barrel, and a water nozzle and a foam induction head movably mounted in such a manner that either one of them can be positioned so that water entering the water inlet is directed through it and thence to the barrel.

Such a cannon can act as a foam cannon or as a water cannon without the need for valves and without the need for dividing the barrel manually. The water nozzle and foam induction head may be movable manually, or by remote control, which makes the cannon ideally suited to applications where it is inconvenient or unsafe for an operator to be in attendance.

Preferably, the water nozzle and foam induction head are mounted on a member which is slidable between two positions in which the water nozzle and the foam induction head, respectively, are positioned to receive water from the water inlet. The sliding movement maybetranslational and in any direction with respect to the horizontal. Preferably, however, the member is slidable in a generally horizontal direction, whereby the effects of gravity tend not to move the member from the selected position.

The sliding movement may instead by rotary.

The invention will now be further described, by way of illustrative and non-limiting example, with reference to the accompanying drawing, in which: Figure lisa top plan view of a foam cannon embodying the invention; Figure 2 is a perspective view of the cannon shown in Figure 1; and Figure 3 is a perspective view, on an enlarged scale, of a water nozzle and foam induction head slidably mounted within an enclosure of the cannon of Figures 1 and 2.

The illustrated cannon comprises a generally boxlike enclosure 10 having fitted thereto a water inlet 12 and a barrel 14, the water inlet and barrel being mutually aligned. The arrangement as illustrated in Figures 1 and 2 is preferably so mounted as to constitute a monitor, of any of the varieties thereof known in the art, whereby the barrel 14 can be pointed in any direction and its angle of elevation can be varied, the longer axis of the enclosure 10 remaining generally horizontal in any such position.

The enclosure 10 comprises a parallelepipepal portion 18 and a pyramidal portion 20, the barrel 14 extending from the apex of the pyramid.

The upper wall 22 of the enclosure portion 18 has a group of air intake holes 24 therein, the holes being positioned halfway along the wall 22 and near the edge of the wall 22 adjacent the other enclosure position 20. A like group of air intakes holes 24 is similarly positioned in the bottom wall (not shown) of the enclosure portion 18.

The water inlet 12 communicates with a hole (not shown) in the rear wall 26 of the enclosure portion 18.

Referring to Figures 1 and 3, a plate 28 is mounted within the closure portion 18, so as to be slidable along the inside of the rear wall 26 thereof, by means of a pair of members 30 secured to the wall 26 to define a slideway. A handle 32 (Figures 1 and 2) is secured to the member 28 and extends out of holes in the end wall 34 of the enclosure portion 18to enable the member 28 to be slid along the slideway.

A water nozzle 36 and a foam induction head 38 are mounted around respective holes (not shown) in the member 28 whereby, by pushing or pulling on the handle 32, either of them may be aligned with the water inlet 12.

A tube 40 extends from the foam induction head 38 out through a hole in the end wall 34 of the enclosure portion 18 and is telescopically received in a tube 42 (Figure 1) which, in use, is connected to a source of a foam compound.

A slide 44 is movable with the member 28 so as to close the air intake holes 24 when the water nozzle 36 is aligned with the water inlet. The slide 44 is schematically shown in Figure 1 as being connected to the member 28 by a member 46, though it may instead be connected to the nozzle 36. A like slide (not shown) is arranged to close the air intake holes in the lower wall (not shown) of the enclosure portion 18 when the water nozzle 36 is aligned with the water inlet 12.

To use the cannon as a foam cannon, assuming that the member 28 is in the intermediate position shown in Figures 1 and 3, the handle 32 is pushed to move the member 28 so that the foam induction head 38 is aligned with the water inlet 12 and so that the slides (such as 44) do not close the air intake holes (such as 24). Water is fed to the inlet 12 under pressure, passes through the head 38 and from there to the barrel 14. The flow of water through the head 38 induces foam compound to flow via the pipes 42, 40 into the water stream. The flow of water between the head 38 and barrel 14 induces air to flow in via the air intake holes (such as 24) and become entrained with the water stream. The water, foam compound and air become mixed whereby foam is ejected from the barrel 14.

To use the cannon as a water cannon, the handle 32 is then pulled to move the member 28 so that the water nozzle 36 is aligned with the water inlet 12 and so that the slides (such as 44) close the air intake holes (such as 24). Foam compound does not enter the enclosure 10 because there is no water flowing through the foam induction head 38to cause it to do so. Substantially no air enters the enclosure 10 because the air intake voles (such as 24) are closed. Water under pressure entering the inlet 12 passes through the nozzle 38 and from there to the barrel 14.

The invention can, of course, be performed in other ways than that described above by way of example. For example, the pyramidal portion 20 of the enclosure 10 can be removed and replaced by a flat front wall for the portion 18, and the nozzle 36 can be lengthened to be nearly flush with such wall and modified so that its outlet cross-section is greater than or at least equal to that of the adjacent end of the barrel 14. In this case, when the nozzle 36 is aligned with the water inlet 12 the water stream in the enclosure 10 is substantially enclosed by the nozzle 36, whereby the slides such as 44 can be omitted since little air will be able to become entrained with the water stream.

In addition to or instead of the handle 32, means may be provided to cause the member 28 to slide between its two positions under remote control The outlet end of the barrel 14 may be provided with a sliding arrangement enabling either a spreaderforfoam laying (when the cannon is used as a foam cannon) or a water spray head (when the cannon is used as a water cannon) to be aligned with the outlet of the barrel. Such a sliding arrangement may be operated manually or under remote control.

Claims

1. A foam cannon comprising a water inlet, a bar rel, and a water nozzle and a foam induction head movably mounted in such a manner that either one of them can be positioned so that water entering the water inlet is directed through it and thence to the barrel.

2. A foam cannon according to claim 1, wherein the water nozzle and foam induction head are mov able manually.

3. A foam cannon according to claim 1 or claim 2, including means to move the water nozzle and foam induction head in response to remote control.

4. A foam cannon according to claim 1, claim 2 or claim 3, wherein the water nozzle and foam induc tion head are mounted on a member which is slid able between two positions in which the water nozzle and the foam induction head, respectively, are positioned to receive water from the water inlet.

5. A foam cannon according to claim 4, wherein the sliding movement is translational.

6. Afoam cannon according to claim 5, wherein the member is slidable in a generally horizontal direction.

7. A foam cannon according to claim 4, wherein the sliding movement is rotary.

8. Afoam cannon substantially as herein described with reference to the accompanying drawing.

New claims or amendments to claims filed on 6/2/81 New or amended claims: Claim 8,9 and 10.

8. A foam cannon according to any one of claims 4 to 7, including slide means movable with said member and operative to close or open an air inlet when the water nozzle or the foam induction head, respectively, is positioned to receive water from the water inlet.

9. Afoam cannon according to any one of the preceding claims, wherein the water inlet and the barrel are mutually aligned.

10. A foam cannon according to any one of the preceding claims, wherein the nozzle and foam induction head are movable within an enclosure to which the water inlet and barrel are fitted.