Fluid delivery system for fire-fighting apparatus

Abstract

 The invention provides a fluid delivery system (10) for a fire-fighting apparatus (100) comprising: first pump means (1) for connection to a first liquid supply for pumping a first liquid to a discharge outlet; and second pump means (2) for connection to a second liquid supply for pumping a second liquid to the discharge outlet. The fluid delivery system (10) is adapted to combine the first and second liquids downstream of said first and second pump means to produce a fire-extinguishing agent which, upon exiting the discharge outlet, is a mixture of said first and second liquids. Each of the first and second pump means (1, 2) is typically a positive displacement pump, preferably a membrane pump. A common drive means (3) is advantageously provided for driving both the first pump means (1) and the second pump means (2) simultaneously. The drive means includes a rotary drive shaft and both the first and second pump means are driven by that rotary drive shaft.

Description

[0001] The present invention relates to a fluid delivery system, and in particular to a fluid delivery system for a fire-fighting apparatus. The present invention also relates to a fire-fighting apparatus incorporating such a fluid delivery system.

[0002] The use of foam-type fire-extinguishing agents is well known in the field fire-fighting. Foam-type extinguishing agents are usually formed from aqueous solutions, making them suitable for class A type fires of general combustible materials. Foam-type fire-extinguishing agents, however, are particularly suitable for use on class B type fires involving burning liquids or grease, because the foam essentially floats on top of the burning liquid to exclude oxygen and thereby smother the flames. Foam-type fire-extinguishing agents are also naturally much less dense than normal liquids, so they tend not to impart much momentum to a burning liquid when they make contact, thereby reducing the risk of spreading the burning liquid around.

[0003] Most foam type fire-extinguishing agents are formed from a mixture of two substances, namely a foaming agent in combination with an aqueous liquid or water. Many known types of fire-fighting equipment that employ foam type extinguishing agents, such as hand-held extinguisher cylinders, contain the extinguishing agent as a liquid under pressure in a pre-mixed state. The foam is then generated upon discharge of the liquid. Other types of fire-fighting equipment may involve the separate storage of a foaming agent and water, with the two only being combined when the equipment is used.

[0004] The present invention aims to provide an improved fluid delivery system for a fire-fighting apparatus, and in particular for a fire-fighting apparatus adapted for use with foam-type fire-extinguishing agents.

[0005] Broadly, the present invention provides a fluid delivery system having the features recited in claim 1. Preferred features of the fluid delivery system are recited in the dependent claims 2 to 14.

[0006] Thus, the present invention provides a fluid delivery system for a fire-fighting apparatus, comprising: first pump means for connection to a first liquid supply for pumping a first liquid to a discharge outlet, and second pump means for connection to a second liquid supply for pumping a second liquid to the discharge outlet; wherein the fluid delivery system is adapted to combine the first and second liquids downstream of the first and second pump means to produce a fire-extinguishing agent which, upon exiting the discharge outlet, is a mixture of said first and second liquids.

[0007] Accordingly, the fluid delivery system of the invention enables two separately stored liquids in a fire-fighting apparatus to be separately pumped and subsequently combined to generate the fire-extinguishing agent. One of the two liquids may comprise water or some suitable aqueous solution, and the other may comprise a foaming agent, such that the combination of the two liquids downstream of the first and second pump means then produces a fire-extinguishing foam. The pressure generated by the first pump means and the second pump means should preferably ensure that the fire-extinguishing agent may exit the discharge outlet in a manner suitable for direct application to a fire. In this regard, the pressure generated by the second pump means may augment the pressure generated by the first pump means to provide an advantageously enhanced pressure at the discharge outlet.

[0008] In a preferred form of the invention, the fluid delivery system comprises a common drive means for driving both the first pump means and the second pump means simultaneously. The drive means preferably comprises a motor that is operable to rotate a drive shaft, with the drive shaft arranged such that rotation thereof simultaneously actuates the first and second pump means. The first and second pump means are preferably located spaced apart from one another along a rotational axis of the drive shaft. Particular advantages of employing a common drive means for the first and second pump means include economy of operation, an economy of space and weight for the system, and uniformity in the operation of the two separate pump means.

[0009] Although the motor of the drive means could be an electric motor, it is preferred that the motor be a combustion engine to enable the fluid delivery system of the invention to be more easily deployed in remote regions where no electrical power source may be readily available. Accordingly, a combustion motor having its own fuel supply enables fully independent operation of the system.

[0010] In a preferred form of the invention, the first pump means and the second pump means are both positive displacement pumps. More preferably, they are both membrane pumps. A significant advantage of employing positive displacement pumps in the fluid delivery system of the present invention is that the relative amounts of the first and second liquids delivered are essentially regulated by the operation of the pumps. In other words, because each of the two pumps has a particular volumetric displacement or capacity, this ultimately dictates the respective volumes of the first and second liquids conveyed by the pumps in any given time period. Accordingly, the metering of the first and second liquids is essentially effected by the pumps themselves, and sophisticated dosing equipment is therefore not required to ensure the correct proportions of the two liquids. In this regard, for foam-type fire-extinguishing agents, a relatively smaller volume of a liquid foaming agent is typically required compared to the volume of the aqueous solution or water to be mixed with it. Thus, the first positive displacement pump for pumping the aqueous solution or water preferably has a larger capacity than the second positive displacement pump for pumping the foaming agent.

[0011] In a preferred form, the fluid delivery system of the invention further comprises a delivery line downstream of, and in fluid connection with, the first and second pump means for conveying the first and second liquids and/or said fire-extinguishing agent, respectively, to the discharge outlet. The delivery line is preferably in the form of a flexible hose and the discharge outlet is preferably formed by a nozzle at a distal end of the flexible hose.

[0012] Furthermore, in a preferred form of the invention, the fluid delivery system further comprises a mixing device downstream of the first pump and the second pump for effecting a suitable mixing of the first and second liquids to produce the foam type fire-extinguishing agent. The mixing device may be installed in the fluid delivery line just mentioned.

[0013] According to another broad aspect, the present invention provides a fire-fighting apparatus comprising a first liquid supply, a second liquid supply, and a fluid delivery system according to the invention as described above.

[0014] In a preferred form, the fire-fighting apparatus of the invention further comprises a rigid frame, with the first liquid supply, the second liquid supply and the fluid delivery system all mounted on the frame. The fire-fighting apparatus of the invention is preferably embodied as a portable unit, with the frame designed to give the unit structural support and integrity. For example, the fire-fighting apparatus of the invention may be suitable for transport on a trailer, or on the back of a utility vehicle or pick-up truck.

[0015] In a preferred form of the invention, the first liquid supply comprises at least one first container for mounting on the frame and the second liquid supply comprises at least one second container for mounting on the frame. The first liquid supply may, however, comprise two or more first containers, and the second liquid supply may likewise comprise two or more second containers.

[0016] For a more complete understanding of the present invention, and without limiting the generality of the preceding description, a preferred embodiment of the fluid delivery system of the invention and a fire-fighting apparatus incorporating same is hereafter described with reference to the accompanying drawings. In the drawings, like reference characters designate like features throughout the several views, and:

Fig. 1 is a perspective view of a fluid delivery system according to a preferred embodiment of the invention;

Fig. 2 is a top view of the fluid delivery system of Fig. 1;

Fig. 3 is an end view of the fluid delivery system shown in Fig. 1;

Fig. 4 is an end view of a fire-fighting apparatus incorporating a fluid delivery system as shown in Fig. 1; and

Fig. 5 is a perspective view of the fire-fighting apparatus shown in Fig. 4.

[0017] Referring firstly to Figs. 1 to 3, a preferred embodiment of a fluid delivery system 10 for a fire-fighting apparatus is illustrated. The fluid delivery system 10 includes a first positive displacement pump 1 for connection to a first liquid supply containing a first liquid (not shown), and second positive displacement pump 2 for connection to a second liquid supply containing a second liquid (not shown). The fluid delivery system 10 further includes a motor 3 in the form of a petrol combustion engine, e.g. a single cylinder two-stroke engine, which serves as a common drive means for the first and second positive displacement pumps 1, 2. The motor 3 has a fuel tank 4 mounted thereon to ensure reliable and independent operation of the system despite potential deployment in remote locations. An exhaust unit 5 can also be seen mounted above a cylinder housing 6 of the combustion motor 3.

[0018] The motor 3 has an associated rotary drive shaft enclosed in a shaft housing 7 and the first and second positive displacement pumps 1, 2 are spaced apart from one another in the direction of the rotational axis of the drive shaft. Importantly, both of the first and second pumps 1, 2 are simultaneously actuated by the rotary drive shaft. By embodying the first and second pumps 1, 2 as membrane pumps, a simultaneous actuation with the common drive shaft can be achieved with a relatively straight-forward mechanism. For example, eccentrics or cam devices operatively connected to the shaft and associated followers may generate the necessary travel or lateral displacement for the pump membranes. A mounting adapter 8 is provided between the first pump 1 and the second pump 2.

[0019] Furthermore, as is quite evident from the drawings, the first pump 1 and the second pumps 2 have different sizes so that the first liquid and the second liquid are delivered by the pumps to a discharge outlet at different rates. This is particularly advantageous as it enables the first and second liquids to be automatically metered by the operation of the two pumps. In particular, since the first and second pumps 1, 2 are positive displacement pumps that are driven simultaneously by a common drive shaft, the relative flow rates of the two liquids are predetermined by the capacity of each pump, and remain essentially constant during operation of the system 10. In this way, the need for complicated dosing equipment and/or for pre-mixing of the two liquids in fixed or predetermined proportions can be avoided. The first and second pumps 1, 2 themselves and/or the mechanism with which the pumps are operatively couple to the drive shaft preferably allow some adjustment to vary the stroke or volumetric capacity of each of the pumps. This, in turn, allows some flexibility to alter the relative proportions and/or flow rates of the first and second liquids conveyed by the fluid delivery system 10.

[0020] Although not immediately apparent from the illustrations in Figs. 1 to 3, the first and second pumps 1, 2 of the fluid delivery system 10 are adapted to pump the first and liquids, respectively, to a discharge outlet. Downstream of the first and second pump means 1, 2, the fluid delivery system 10 is adapted to combine the first and second liquids to produce a fire-extinguishing agent which may then exit the discharge outlet as a mixture of said first and second liquids. This configuration of the fluid delivery system 10 will be clearer from Figs. 4 and 5, which more fully illustrate the preferred embodiment of the fluid delivery system 10 mounted within a fire-fighting apparatus 100. Indeed, as can be seen in Figs. 1 and 3 of the drawings, a footing 9 is provided at a base of an engine casing 11 and a footing 12 is provided on a base of the first pump 1. These footings 9, 12 are adapted for securely mounting the fluid delivery system 10 on a frame 20 of the fire-fighting apparatus 100.

[0021] With reference then to Fig. 4, the fluid delivery system 10 of the invention is shown mounted on a horizontal frame member 21 of the fire-fighting apparatus 100 supported by its footings 9, 12. A fluid delivery line 13 of the system 10 extends from a pipe junction 14, which is in fluid connection with both the first pump 1 and the second pump 2 at the downstream sides thereof. Accordingly, the first and second liquids pumped by the first pump 1 and the second pump 2, respectively, combine and mix in the delivery line 13 and/or at the pipe junction 14 to produce an extinguishing agent, which is then conveyed under the pressure generated by the pumps to the discharge outlet of the system.

[0022] The delivery line 13 is embodied here as a flexible hose, which is stored coiled on a hose reel 15. The discharge outlet is formed by a hand-held nozzle 16 provided at an end thereof. Accordingly, the user can draw the desired length of hose from its storage reel 15 mounted under the pumps 1, 2 to manually direct the fire-extinguishing agent to the point of desired application. The nozzle 16 may also incorporate a valve for selectively starting and stopping the flow of the fire-extinguishing agent. A manually operable handle 17 is also provided for re-coiling the flexible hose 13 onto the reel 15 after use.

[0023] Referring now to Fig. 5 of the drawings, the fire-fighting apparatus 100 includes multiple containers mounted on the frame 20. Two of the containers 31 form a first liquid supply and contain a first liquid, such as water. The other container 32 forms a separate liquid supply and contains a second liquid, such as a foaming agent. Accordingly, the first pump 1 is in connection with the first two containers 31 and the second pump 2 is in connection with the other container 32. In a particularly preferred embodiment of the invention, the sizes of the containers may be varied to ensure that the optimum quantity of the two liquids is provided in view of the relative amounts of each liquid delivered by the pumps 1, 2. In the present case, the first and second pumps would optimally combine the water and the foaming agent in a ratio of 2:1- that way both of the first and second liquid supplies 31, 32 would be exhausted at approximately the same time. The arrangement of the containers could be modified, however, to account for any change in the pumping ratio.

[0024] Thus, the fluid delivery system 10 of the present invention enables two separately stored liquids in a fire-fighting apparatus 100 to be separately pumped and subsequently combined to generate a desired fire-extinguishing agent. It may be possible, however, to nevertheless use the fluid delivery system 10 of the invention with a single liquid. That is, the same liquid may be contained in both of the first and second liquid supplies 31, 32. Alternatively, it may be possible to selectively shut down or disconnect one of the first and second pumps 1, 2 so that liquid is pumped from only one or the other of the liquid supplies.

[0025] It will be appreciated by persons skilled in the art that the various modifications and/or additions may be made to the particular construction and arrangement of the parts described above with reference to the drawings without departing from the scope of the present invention as defined in the appended claims.

Claims

1. Fluid delivery system for a fire-fighting apparatus, comprising:

first pump means for connection to a first liquid supply for pumping a first liquid to a discharge outlet; and

second pump means for connection to a second liquid supply for pumping a second liquid to said discharge outlet;

wherein the fluid delivery system is adapted to combine the first and second liquids downstream of said first and second pump means to produce a fire-extinguishing agent which, upon exiting the discharge outlet, is a mixture of said first and second liquids.

2. Fluid delivery system according to claim 1, wherein pressure generated by the first pump means and the second pump means ensures that the fire-extinguishing agent may exit the discharge outlet in a manner suitable for application to a fire.

3. Fluid delivery system according to claim 1 or claim 2, further comprising a common drive means for driving both the first pump means and the second pump means simultaneously.

4. Fluid delivery system according to claim 3, wherein the drive means includes a rotary drive shaft and wherein both the first and second pump means are driven by said rotary drive shaft.

5. Fluid delivery system according to claim 4, wherein the first and second pump means are located spaced apart from one another along a rotational axis of said drive shaft.

6. Fluid delivery system according to claim 4 or claim 5, wherein the drive means comprises a motor operatively coupled to the drive shaft for rotation of same, said motor preferably comprising a combustion engine.

7. Fluid delivery system according to any one of claims 1 to 6, wherein each of the first pump means and the second pump means is a positive displacement pump.

8. Fluid delivery system according to claim 7, wherein the first pump means and the second pump means are both membrane pumps.

9. Fluid delivery system according to claim 7 or claim 8, wherein the first pump means has a larger capacity than the second pump means.

10. Fluid delivery system according to any one of claims 1 to 9, further comprising a delivery line downstream of, and in fluid connection with, said first and second pump means for conveying the first and second liquids or said fire-extinguishing agent, respectively, to the discharge outlet, wherein said discharge outlet is at a distal end of said delivery line.

11. Fluid delivery system according to claim 10, wherein said delivery line is a flexible hose and the discharge outlet is formed by a nozzle at the distal end of said flexible hose.

12. Fluid delivery system according to any one of claims 1 to 11, further comprising a mixing device downstream of the first pump means and the second pump means for combining the first and second liquids to produce said fire-extinguishing agent.

13. Fluid delivery system according to claim 12, wherein the mixing device is provided in the delivery line.

14. Fluid delivery system according to claim 12 or claim 13, wherein the mixing device is adapted to generate a foam-type fire-extinguishing agent.

15. Fire-fighting apparatus comprising a first liquid supply, a second liquid supply, and a fluid delivery system according to any one of claims 1 to 14.

16. Fire-fighting apparatus according to claim 15, further comprising a substantially rigid frame, wherein the first liquid supply, the second liquid supply and the fluid delivery system are all mounted on said frame.

17. Fire-fighting apparatus according to claim 16, wherein the first liquid supply comprises at least one first container and the second liquid supply comprises at least one second container.

Drawing