PRESSURISED CONTAINER

Abstract

A fire suppression apparatus (1000) comprises an enclosed hollow cylinder (1100) for containing a firefighting agent (not shown). The cylinder (1100) has a cylindrical side wall (1110) and upper and lower dome-ends (1120) and (1130), respectively. The lower end (1130) features supporting feet (1132). At the upper end (1120), an outlet valve (1122) is mounted on a neck-ring (1123) of the cylinder. The valve (1122) comprises an inlet connected to a dip-tube 1200 having a venturi device (1300). The valve itself comprises an outlet (1124). A nozzle, or distribution network to nozzle(s), (not shown) may be attached to threaded stub (1126) to direct firefighting agent during discharge.

Claims

1. A container for containing a dischargeable agent under pressure, the container comprising a discharge conduit through which agent is arranged to pass during discharge under the influence of a pressurised gas, wherein part of the dip-tube comprises a venturi device.

2. A container according to claim 1, wherein the container comprises a fire-suppressing apparatus for containing a firefighting agent.

3. A container according to claim 1, wherein the venturi device is located upstream of a valve or adaptor of the apparatus.

4. A container according to claim 1, wherein the venturi device comprises at least a part of a main pathway for the passage of the agent during discharge.

5. A container according to claim 1, wherein at least one aerator duct extends into the discharge conduit from an interior space of the container.

6. A container according to claim 5, wherein the aerator duct extends through a wall of the venturi device to fluidically connect an interior of the venturi device with the interior space of the container.

7. A container according to claim 1, wherein the venturi device defines a flow axis and comprises an entry stage with respect to a flow direction of agent during discharge.

8. A container according to claim 1 wherein the venturi device includes a throat part.

9. A container according to claim 1, wherein the venturi device includes an exit part with respect to a flow direction of agent during discharge.

10. A method of discharging an agent from a container containing the agent under the action of a pressurised expellant gas, the method comprising directing the agent through a discharge conduit comprising a venturi device within the container.

11. A method of discharging an agent from a container according to claim wherein the agent is a firefighting agent.

12. A method according to claim 10, wherein the method comprises aerating the agent as it passes through the venturi device using fluid flowing from an interior of the container into the venturi device through an aerator duct extending from the interior volume of the container into the discharge conduit.

Description

[0024] A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:

[0025] FIG. 1 shows, in part sectional view, a fire suppression apparatus in the form of a cylinder, being in accordance with an embodiment of the present invention;

[0026] FIG. 2 is a more detailed view of part of the apparatus of FIG. 1;

[0027] FIG. 3 shows a fire suppression apparatus in accordance with an alternative embodiment of the present invention; and

[0028] FIG. 4 is a more detailed view of a part of the apparatus of FIG. 3.

[0029] Turning to FIG. 1, this shows, in part sectional view, generally at 1000, a fire suppression apparatus comprising an enclosed hollow cylinder 1100 for containing a firefighting agent (not shown) and an expellant gas under pressure. The cylinder 1100 has a cylindrical side wall 1110 and upper and lower dome-ends 1120 and 1130, respectively. The lower end 1130 features supporting feet 1132. At the upper end 1120, an outlet valve 1122 is mounted on a neck-ring 1123 of the cylinder. The valve 1122 comprises an inlet connected to a dip-tube 1200 having a venturi device 1300. The valve itself comprises an outlet 1124. A nozzle, or distribution network to nozzle(s), (not shown) may be attached to threaded stub 1126 to direct firefighting agent during discharge.

[0030] Inside the cylinder, in fluidic communication with the outlet, the dip tube 1200 extends substantially along a longitudinal axis of the cylinder towards the lower end 1130 thereof. The venturi device 1300 is located close to the upper end 1120, which will be described below with reference to FIG. 2.

[0031] FIG. 2 is an enlarged view of the venturi device 1300 of FIG. 1. The venturi device 1300 comprises a frusto-conical convergent entry stage 1310, a cylindrical throat stage 1320 and a frusto-conical divergent exit stage 1330 all within a machined body 1340. The venturi device 1300 is threadedly connected in-line with the dip tube 1200 between an inlet run portion 1210 and an outlet run portion 1220 thereof.

[0032] Arrow A1 shows the direction of flow of firefighting agent during discharge.

[0033] An aerator duct 1350 extends between the throat stage 1320 and the exterior of the venturi device 1300i.e. into the surrounding volume of the cylinder 1110.

[0034] When the outlet valve is opened, the consequent reduction in pressure in the dip tube causes the expellant gas to force the firefighting agent up the dip tube and ultimately through of the outlet valve. However, due to the Venturi Effect, when the agent flows through the venturi device 1300 the pressure there is further reduced whilst the velocity increases. This assists in drawing up agent from the bottom of the cylinder which might otherwise remain there as the expellant gas becomes exhausted. In this way, the yield of the apparatus is improved.

[0035] Furthermore, the aerator duct 1350 introduces a jet of expellant gas or (if below the fill level of agent) agent directly into the throat stage which disrupts the flow of agent through the venturi device. This is useful in a number of ways:

[0036] Where the agent is a liquid with a foaming component, the aeration jet agitates the liquid to improve the foaming process.

[0037] Where the agent is a liquid or liquified gas having a low vapour pressure, such as a halogenated compound, the aeration jet reduces the concentration of the agent allowing higher ratios of vapour-liquid phases due to the increased mixing with expellant gas reducing the proportion of the agent that becomes a gas prior to it reaching the nozzle. Furthermore, due to the pressure drop as a result of the venturi effect, the device promotes the transition of liquid to vapour.

[0038] Where the agent is a powder, the aeration jet promotes a more homogenous mixture of propellant and agent, whilst also increasing the momentum of the powder.

[0039] FIGS. 3 and 4 show an alternative embodiment of the present invention in which the venturi device 1300 is located partly within the valve assembly 1122, immediately before the valve 1124. In other respects, the device and its effect are substantially the same.

[0040] Embodiments of the invention promote increased yield of firefighting apparatus and can be used either with containers storing pressurised expellant gas therein as well as those using a cartridge to deliver the expellant. There are additional advantages provided by the aerator duct or ducts which improve the combination of expellant gas and agent, and hence the discharge process.

[0041] The venturi device may be used as an in-line component in the dip tube or else may be fittedor designed intothe outlet valve or outlet adaptor. The ratio of the throat stage diameter to the diameter of the entry and/or exit stages of the venturi device and/or to the diameter of the dip tube itself, and indeed the ratio of the inlet and outlet run portions of the dip tube, may be chosen according to the type of agent being discharged. Depending on the characteristics desired, the aerator duct or ducts may be incorporated into the inlet run of the dip tube, the entry, throat or exit stages of the venturi device or the outlet run of the dip tube, or indeed a combination of these.

[0042] The aerator duct may be placed above or below the fill-level of the agent, depending on the desired flow characteristics. The cross-sectional area of the aerator duct may also be varied accordingly. Furthermore, the angle of convergence/divergence of the entry and exit stages of the venturi device may be selected according to desired performance.

[0043] Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the applicant claims protection in respect of any patentable feature or combination of features referred to herein, and/or shown in the drawings, whether or not particular emphasis has been placed thereon.