GB2203065A

GB2203065A - Foam dispensing nozzle

Info

Publication number: GB2203065A
Application number: GB08708741A
Authority: GB
Inventors: Robert Alan Whiteley
Original assignee: Wormald Ansul UK Ltd
Current assignee: Tyco Fire and Integrated Solutions UK Ltd
Priority date: 1987-04-11
Filing date: 1987-04-11
Publication date: 1988-10-12
Also published as: GB8708741D0

Abstract

A nozzle for use in fire fighting comprises a barrel (1) defining an inlet (4) for the supply of a pressurised fluid to the nozzle, a port (9) for the supply of a foam concentrate to the nozzle, and an outlet for the egress of a foam solution from the nozzle. A primary venturi inductor (8) is provided adjacent said port to enable the foam concentrate to be drawn into the barrel. A deflector (12) is located adjacent the outlet to mix the pressurised fluid in the barrel with the concentrate in order to create a spray of foam solution egressing from the nozzle. The deflector is provided with a plurality of passageways (17) defining a secondary venturi inductor and through which a proportion of the pressurised fluid can pass to create a venturi induction effect and thereby increase the suction power of the nozzle. <IMAGE>

Description

A FOAM NOZZLE The present invention relates to a foam nozzle and particularly to a foam nozzle for use in fire fighting.

Conventional fire fighting foam nozzles are designed to create a foam stream by mixing a foam concentrate with a fluid jet, usually a water jet, and to enable an operator to direct the resulting stream towards a fire. In a typical nozzle, foam concentrate is drawn into the nozzle by a venturi effect created by the passage of pressurised water through a constriction formed within the nozzle. It is an object of the present invention to provide a foam nozzle with an increased suction power over conventional nozzles so that foam concentrate can be drawn in from a supply located further away from the nozzle than hitherto has been possible. In this way the operator's job in locating the foam concentrate supply in a convenient position relative to the nozzle and the pressurized fluid supply is eased, particularly in difficult fire fighting situations.

According to the present invention there is provided a foam nozzle comprising a barrel defining an inlet for the supply of a pressurised fluid to the nozzle, a port for the supply of a foam concentrate to the nozzle, and an outlet for the egress of a foam solution from the nozzle, means adjacent said port to enable the foam concentrate to be drawn into the barrel, and a deflector located adjacent the outlet to mix the pressurised fluid in the barrel with the concentrate in order to create a spray of foam solution egressing from the nozzle, the head being provided with a plurality of passageways therethrough through which a proportion of the pressurised fluid can pass to create a venturi induction effect and thereby increase the suction power of the nozzle.

Preferably, said means comprise a primary venturi inductor formed within the barrel adjacent the port and said passageways through the deflector comprise a secondary venturi inductor.

Preferably also, the passageways are spaced radially around the deflector.

Preferably also, the longitudinal axis of each passageway is angled outwardly of the longitudinal axis of the barrel with respect to the direction of flow through the barrel.

An example of the present invention will now be described with reference to the accompanying drawings which shows a longitudinal cross-section through a foam nozzle.

The nozzle comprises a barrel 1 defining a major outer passageway 2 and an inner central passageway 3. At one end of the barrel 1 is a screw threaded inlet port 4 to allow the nozzle to be attached to a hose supplying pressurised water or other fluid to the passageways 2 and 3.

The barrel 1 is provided with an outer sleeve 5, which can be moved longitudinally and circumferentially with respect to the barrel 1 to the position shown in dotted lines in the drawing by movement of an internal projection 6 along a spiral groove 7 formed on the outer surface of the barrel 1.

Located within the outer passageway 2 and attached to the barrel 1 is a venturi inductor tube 8, which feeds into the inner passageway 3. The longitudinal axes of the tube 8 and the nozzle coincide and, as can be seen in the drawing, a proportion of the fluid entering the inlet 4 will enter the tube 8 and thence passageway 3 although the major portion will pass through passageway 2.

Adjacent the tube 8 and formed radially in the barrel is an inlet port 9 for the supply of a foam concentrate to the nozzle. The inlet port 9 is also screw threaded as at 10 so that a supply hose can be attached thereto.

At the end of the nozzle opposite the inlet 4, the barrel 1 is formed with an annular projection 11 so that the radial width of the outer passageway 2 is reduced. In addition, the portion of the barrel 1 defining the inner passageway 3 flares outwardly at its end to define a mushroom-shaped deflector 12, which additionally constricts the width of the passageway 2. Screwed to the deflector 12 is a deflector plate 13, which is spaced from the deflector by spacer washers 14. The deflector plate 13 completely covers the open end of the inner passageway 3 so that fluid egressing therefrom is forced radially outwards into an annular passageway 15. In addition, the shape of the projection 11 and the deflector 12 together also define an outwardly flaring passageway 16 for the egress of fluid from the outer passageway 3 of the barrel 1.

Formed within the deflector 12 is a plurality of passageways 17, which communicate the outwardly flaring passageway 16 with the annular passageway 15 between the deflector 12 and the plate 13. The passageways 17 are spaced radially around the deflector 12 and their longitudinal axes are angled outwardly of the longitudinal axis of the nozzle with respect to the direction of fluid flow therethrough.

In use, water or other pressurised fluid enters the nozzle through the inlet 4 and a proportion will enter the venturi inductor tube 8 whilst the majority will flow through the passageway 2 in the barrel 1.

The fluid entering the venturi tube 8 is accelerated and creates suction conditions which draws in foam concentrate through the port 9. A rich foam mixture is thus formed within the inner passageway 3.

At the end of the barrel 1, the rich foam mixture within the passageway 3 impinges on the deflector plate 13 and is forced outwardly into the passageway 15 to meet the main fluid flow egressing from the passageway 16. However, the main fluid flow is forced past the projection 11 into the constricted passageway 16 and a proportion thereof flows into the radial passageways 17 formed in the deflector 12.

The flow of fluid through the passageways 17 creates a second venturi inductor effect which draws the rich foam mixture out of the passageway 3 and increases the suction power of the nozzle.

By means of the second venturi inductor, the deflector 12 and the plate 13, the rich foam mixture and the fluid egressing from the passageways 15 and 16 are mixed together and form a foam solution, which can be directed as required. The sleeve 5 can be screwed along the barrel 1 from a first position, as shown in heavy lines in the drawing, to permit a wide angle spray of foam solution to egress from the nozzle, to a final position, as shown in dashed lines, to direct the flow into a straighter jet stream.

It has been found that using water to supply the nozzle from a standard mains supply, that the provision of the second venturi effect within the nozzle enables foam concentrate to be drawn from a supply up to five metres below the level of the nozzle. This compares favourably with conventional nozzles of this type, which typically can only draw up the foam concentrate for a distance of two metres, and thus facilitates the supply of foam concentrate particularly in difficult fire fighting situations.

Claims

CLAIMS:

1. A foam nozzle comprising a barrel defining an inlet for the supply of a pressurised fluid to the nozzle, a port for the supply of a foam concentrate to the nozzle, and an outlet for the egress of a foam solution from the nozzle, means adjacent said port to enable the foam concentrate to be drawn into the barrel, and a deflector located adjacent the outlet to mix the pressurised fluid in the barrel with the concentratr in order to 'reace a spray of foam solution egressing from the nozzle, the deflector being provided with a plurality of passageways theret.hrniiah thhrough which nrcn r the pressurised fluid can pass to create a venturi suction effect and thereby increase the suction power of the nozzle.

2. A foam ..czzle t lid in claim 1, in which the means for drawing the foam concentrate into the barrel comprises a primary venturi inductor formed within the barrel adjacent the port, the passageways through the deflector defining a secondary venturi inductor.

3. A foam nozzle as claimed in claim 1 or 2, in which the passageways are spaced radially around the deflector.

4. A foam nozzle as claimed in any one of claims 1 to 3, in which the longitudinal axis of each passageway is angled outwardly of the longitudinal axis of the barrel with respect to the direction of flow through the barrel.

5. A foam nozzle, substantially as hereinbefore described with reference to the accompanying drawing.