EP3943165A1 - Method for the production of a liquid working foam and foam preparation apparatus - Google Patents

Abstract

A method for providing a liquid working foam agent (19) takes place with the following steps:
- Providing a viscous starting foaming agent in a reservoir (20),
- Entry of energy into the reservoir (20) for liquefying the starting foaming agent to obtain a working foaming agent (19) that is more fluid than the starting foaming agent and has a lower viscosity than the starting foaming agent.

Description

The invention relates to a method for providing a liquid working foam composition and a foam preparation device.

Processes for providing liquid working foam agents and associated foam preparation devices have long been known, particularly in the field of firefighting. Relevant here is the standard DIN EN 16327.

The mentioned foam preparation devices are typically installed in a fire fighting vehicle to improve the extinguishing efficiency. Chemical solutions or foam concentrates are added to the extinguishing water before or after the fire extinguishing centrifugal pump. Compressed air can be injected for final foam formation.

The foam preparation devices may be in the form of pressure proportioning systems (DP) which use a foam concentrate pump to inject the foam concentrate into the water stream at a pressure greater than the water pressure. Once a water-foaming agent solution would be made, the final foam is created by adding air to the Extinguishing jet pipe is initiated as "jet pipe foaming".

An alternative to "jet pipe foaming" is a so-called compressed air foam system (DLS), in which the foaming agent and air are continuously fed to the fire-fighting water after a fire-fighting centrifugal pump under pressure.

Alternatively, it is possible to provide foam admixture on the intake side.

In the development of foaming agents, foam concentrates with a relatively high viscosity are increasingly being used. However, such foam concentrates or foaming agents make suction by foam delivery pumps more difficult or even make this impossible.

The object of the invention is therefore to provide a method for providing a liquid working foam agent and a foam preparation device with which foam agents with a relatively high viscosity can also be used reliably and safely.

This object is achieved by a method for providing a liquid working foaming agent having the features of independent claim 1 and a foam preparation device having the features of independent claim 11. Further developments of the invention are presented in the dependent claims.

• Bereitstellen eines viskosen Ausgangs-Schaummittels in einem Vorratsbehälter,
• Eintrag von Energie in den Vorratsbehälter zur Verflüssigung des Ausgangs-Schaummittels zum Erhalt eines im Vergleich zum Ausgangs-Schaummittel fließfähigeren Arbeits-Schaummittels mit gegenüber dem Ausgangs-Schaummittel geringeren Viskosität.

The method according to the invention for providing a liquid working foam concentrate takes place with the following steps:

• providing a starting viscous foaming agent in a reservoir,
• Entry of energy into the reservoir for liquefying the starting foaming agent to obtain a working foaming agent that is more fluid than the starting foaming agent and has a lower viscosity than the starting foaming agent.

The introduction of energy into the reservoir thus results in a liquefaction of the viscous starting foaming agent, in particular this causes shear liquefaction. The resulting working foam agent is more flowable and can in particular be sucked in by means of a foam feed pump, as a result of which the flowable working foam agent can be used, for example, in a pressure proportioning system or a compressed air foam system.

In a further development of the invention, the energy is introduced by increasing the internal pressure of the reservoir.

The internal pressure can be increased, for example, by feeding a pressurized fluid, in particular compressed air, into the reservoir. Since compressed air is already available in a compressed air foam system for injection into a foaming agent-water mixture or foaming agent solution, there is not a great deal of design work to be done here.

As an alternative or in addition to the energy input by increasing the internal pressure, the energy input can also take place by increasing the temperature of the starting foaming agent.

In a further development of the invention, the working foam agent is discharged from the reservoir at least partly due to the energy input into the reservoir. In the case of energy input by increasing the internal pressure, the resulting flowable working foam agent can be at least partially pressed out of the reservoir.

In a development of the invention, a foam pump, for example in the form of a foam proportioning pump, or an inductor, in particular a Venturi inductor, is used to convey the working foam agent.

In a development of the invention, the reservoir is a pressure tank.

It is possible that the starting/working foam concentrate is a shear thinning or thixotropic fluid.

Alternatively, it is also conceivable that the starting/working foam agent is a Bingham fluid.

In a further development of the invention, water and pressurized fluid are fed to the working foam compound to produce a foam compound solution/air mixture.

The foam preparation device according to the invention has a foaming agent supply device for preparing a liquid working foaming agent, which has a storage container for storing a viscous starting foaming agent and an energy input device for introducing energy to liquefy the starting foaming agent to obtain a working fluid that is more flowable than the starting foaming agent. Having foaming agent, and with a mixing device for mixing the working foam concentrate with water to form a foam concentrate solution.

The energy input device thus provides for the energy input that is available for the liquefaction of the viscous starting foaming agent.

In a development of the invention, the energy input device is designed as a pressure fluid supply device for supplying pressure fluid, in particular compressed air, into the reservoir. The pressurized fluid supply device has in particular a compressor, in particular a compressed air compressor. Particularly preferably, the pressurized fluid supply device has at least one valve, which is expediently connected in the supply line from the compressor to the reservoir, in order to selectively enable or shut off a pressurized fluid supply to the reservoir. The valve can be designed, for example, as a 2/2 or 3/2 valve, with the latter being able to vent the pressurized reservoir.

In a development of the invention, a conveying device for conveying the working foam agent into the mixing device is provided between the storage container and the mixing device.

In a particularly preferred manner, the conveying device has a foam pump or an inductor.

In a development of the invention, a pressurized fluid supply device is provided for supplying compressed air to produce a foam agent solution/air mixture. It is possible that this is one of the pressurized fluid supply device for liquefying the starting foaming agent separate pressurized fluid supply device or, alternatively, it can also be the pressurized fluid supply device that is already used to liquefy the starting foaming agent. It is thus possible, for example, for the compressor, which is available anyway for injecting the compressed air for producing the foaming agent solution/air mixture, to also provide the compressed air for liquefying the starting foaming agent. Alternatively, a separate compressor can also be used, which only provides the compressed air for the liquefaction of the starting foam compound.

Figur 1

ein schematisches Anlagendiagramm eines bevorzugten Ausführungsbeispiels der erfindungsgemäßen Schaumzubereitungsvorrichtung und

Figur 2

eine schematische vergrößerte Darstellung der Einzelheit X aus Figur 1.

A preferred embodiment of the invention is shown in the drawing and is explained in more detail below. Show in the drawing:

figure 1

a schematic plant diagram of a preferred embodiment of the foam preparation device according to the invention and

figure 2

a schematic enlarged representation of the detail X from figure 1 .

the figure 1 shows a schematic system diagram of a preferred exemplary embodiment of the foam preparation device 11 according to the invention. The foam preparation device 11 according to the invention is described below by way of example as a system installed in a fire engine. In the example described, the foam preparation device 11 is designed as a compressed air foam system (DLS).

As in particular in figure 1 shown includes the foam preparation device 11, a fire-fighting water pump 12, in particular in the form of a fire-fighting centrifugal pump through the Vehicle drive or a separate drive, such as an electric auxiliary drive, is driven.

The fire-fighting water pump 12 is able to suck in fire-fighting water via suction lines 13, of which only one is shown in the system diagram, and discharge it on the pressure side via pressure lines 14a, 14b.

In the example shown, one of the pressure lines 14a is connected to a jet pipe 15 via a suitable fire hose. The other pressure line 14b leads to another component of the foam preparation device 11, namely a mixing device 16. The mixing device 16 has an associated extinguishing water input 17, via which the extinguishing water pumped by the extinguishing water pump can be supplied.

As in particular in figure 1 shown, the foam preparation device 11 comprises a foam preparation device 18 for preparing a liquid working foam preparation 19. The foam preparation device 11 in turn comprises several components, of which a reservoir 20 for storing a viscous starting foam preparation belongs to it. The reservoir 20 is designed as a pressure tank in the example.

Another important component of the foaming agent supply device 18 is an energy input device 21 for the input of energy to liquefy the viscous starting foaming agent to obtain a working foaming agent 19 that is more fluid than the starting foaming agent.

The energy input device 21 is designed in the example described as a pressure fluid supply device, so that the energy input in the form of the supply of pressure fluid, in particular compressed air, takes place. In the following, the pressure fluid supply is described as a compressed air supply in the example case.

As in particular in figure 1 shown, the reservoir 20 has for this purpose a compressed air inlet 22, via which compressed air can be introduced into the interior of the reservoir 20, and a foaming agent outlet 23, via which liquefied working foaming agent 19 can be discharged from the reservoir 20.

The energy input device 21 in the form of the compressed air supply device includes a compressed air compressor 24 for generating the required compressed air.

According to a first variant, the compressed air compressor is a separate compressor 24a and in the second variant it is a compressed air compressor 24b, which is already present in the foam preparation device in the form of the compressed air foam system, as described in more detail below. According to the first embodiment, compressed air is fed via a compressed air line 25a to a valve 26, via which the compressed air feed into the reservoir 20 can be controlled.

According to the second embodiment variant, compressed air is also supplied to the valve 26 via another compressed air line 25b from the associated compressed air compressor 24b.

The valve can be a 2/2-way valve with which the compressed air supply to the reservoir can be opened or blocked in the other position of the valve. Alternatively, a 3/2-way valve can also be used, which has a venting function as an additional function pressurized reservoir 20 has a separate vent line.

Another important component of the foam agent supply device 18 in the example shown is a foam pump 27, via which the liquefied working foam agent 19 is sucked in from the reservoir 20 via the foam agent outlet 23 and via a foam agent suction line 28 and discharged via a foam agent pressure line 29. The foaming agent pressure line 29 opens into the mixing device 16 via a foaming agent inlet 30.

Another important component of the foam preparation device 11 is the already mentioned compressed air compressor 24a, which supplies compressed air to the mixing device 16 via an injection line 31 . Compressed air reaches the mixing device 16 via a compressed air inlet 32.

the figure 2 shows an enlarged view of the reservoir with the associated valve 26, the working foam agent 19 already liquefied therein and the foam agent outlet 23, in particular at the sump of the reservoir 20.

The foam is prepared using the foam preparation device 11 according to the invention in the form of the compressed air foam system as follows:
First, liquid working foam 19 is provided.

This is done by providing viscous, in particular highly viscous, starting foaming agent in the reservoir 20 . This viscous starting foaming agent, which is in particular a pseudoplastic or thixotropic Fluid is, is poorly flowable, making suction by means of the foam pump 27 is made difficult or impossible. Therefore, the viscous starting foam concentrate is liquefied by the input of energy in the form of compressed air. For this purpose, compressed air provided either by the external compressed air compressor 24a or by the injection compressed air compressor 24b is introduced into the reservoir 20 via the associated compressed air lines 25a, 25b and the valve 26 switched on in the compressed air lines. The internal pressure in the reservoir 20 then increases, as a result of which the viscous starting foaming agent liquefies to form a working foaming agent 19 which is more flowable and can therefore be conveyed by the foam pump 27 .

The foaming agent is withdrawn from the reservoir 20 at the foaming agent outlet 23 and fed to the mixing device 16 via the foaming agent pressure line 29 . At the same time, extinguishing water is sucked in by the extinguishing water pump 12 in the form of the fire extinguishing centrifugal pump via the suction line 13 and is also supplied to the mixing device 16 via the pressure line 14a via the extinguishing water inlet 17 .

In the mixing device 16, water and working foam compound are mixed to form a foam compound solution. In addition, compressed air is also fed to the mixing device 16 via the injection compressed air compressor 24b via the injection line 31 and the compressed air inlet 32, so that the foam agent solution present in the mixing device 16 is additionally injected with compressed air. This creates a foam compound solution/air mixture. The foaming agent-air mixture is then fed via an outlet line 33 to associated jet pipes 34a, 34b.

The foam compound solution/air mixture can then be used for firefighting via the nozzles.

Claims (15)

Method for providing a liquid working foam concentrate (19), the method with the following steps: - Providing a viscous starting foaming agent in a reservoir (20), - Entry of energy into the reservoir (20) for liquefying the starting foaming agent to obtain a working foaming agent (19) which is more fluid than the starting foaming agent and has a lower viscosity than the starting foaming agent. Method according to Claim 1, characterized in that the energy is introduced by increasing the internal pressure of the storage container (20). Method according to Claim 1 or 2, characterized in that the internal pressure is increased by supplying a pressure fluid, in particular compressed air. Method according to one of the preceding claims, characterized in that the energy input takes place by increasing the temperature of the starting foaming agent. Method according to one of the preceding claims, characterized in that the application of the working foam (19) from the storage container (12) at least partially due to the energy input into the reservoir (20). Method according to one of the preceding claims, characterized in that a foam pump (27) or an inductor, in particular a Venturi inductor, is used to convey the working foam agent (19). Method according to one of the preceding claims, characterized in that the storage container (20) is a pressure tank. Method according to one of the preceding claims, characterized in that the starting/working foaming agent is a pseudoplastic or thixotropic fluid. A method according to any one of claims 1 to 7 characterized in that the starting/working foaming agent is Bingham fluid. Method according to one of the preceding claims, characterized in that the working foam agent (19) is supplied with water and pressurized fluid to produce a foam agent solution/pressurized fluid mixture. Foam preparation device, with a foaming agent supply device (18) for providing a liquid working foaming agent (19), which has a storage container (20) for storing a viscous starting foaming agent and an energy input device (21) for the input of energy for liquefying the starting foaming agent to obtain it a working foaming agent (19) that is more flowable than the starting foaming agent, with a relative to the starting foaming agent having lower viscosity, and with a mixing device (16) for mixing the working foam agent (19) with water to form a foam agent solution. Foam preparation device according to Claim 11, characterized in that the energy input device (21) is designed as a pressurized fluid supply device for supplying pressurized fluid, in particular compressed air, into the reservoir (20), the pressurized fluid supply device preferably having a compressor, in particular a compressed air compressor (24a, 24b). . Foam preparation device according to one of Claims 11 or 12, characterized by a conveying device connected between the storage container (20) and the mixing device (16) for conveying the working foam agent (19) into the mixing device (16). Foam preparation device according to Claim 13, characterized in that the conveying device has a foam pump (27) or an inductor. Foam preparation device according to one of Claims 11 to 14, characterized by a pressurized fluid supply device for supplying compressed air to produce a foaming agent solution/pressurized fluid mixture, the pressurized fluid supplying device for preparing the foaming agent solution/pressurized fluid mixture preferably being the same as that used to liquefy the starting foaming agent .

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