DE102012004680A1 - Apparatus and method for providing a foam - Google Patents

Abstract

The inventive device (12) for providing a foam, comprising a foaming chamber (1), having - at least one mixing port (2) for supplying a mixture of water and foaming agent, - at least one gas port (3) for supplying pressurized gas and - At least one hose connection (5) for discharging the foam; is characterized in that the foaming chamber (1) further comprises at least one water connection (4) for supplying water. The device (12) for providing a foam can preferably be used to provide extinguishing foam. The further water connection (4) for introducing water directly into the foaming chamber (1) can influence the foam quality, in particular with regard to the foaming number and the flowability of the foam. As a result, the device (12) can be used in a wide variety of situations.

Description

The subject of the present invention is an apparatus and a method for providing a foam. The device according to the invention and the method according to the invention can be used in particular in the provision of fire-extinguishing foam.

In particular, in industrial companies, it is necessary and mandatory to provide fire-extinguishing equipment at potentially fire-endangered points such as corresponding machines. Foaming devices are often used here, via which a foam such as fire-fighting foam for fire fighting can be generated. Fire-extinguishing foam usually consists of a filling gas, such as air or nitrogen, water and a foaming agent. For this purpose, the foaming agent is usually kept ready with appropriate equipment at the necessary locations, where there is a water connection and optionally a compressed gas connection for the use of these devices. Should a use be necessary, a foaming chamber is supplied with foaming agent, water and compressed air, whereby a foam is produced. This extinguishing foam can be used for fire fighting on site or transported to the source of fire, for example, by appropriate hose lines. For example, it may be necessary in case of fire in a machine to enter the extinguishing foam at a designated opening in the machine and to flood them with the extinguishing foam.

The previously known solutions, especially small, compact and mobile solutions for providing foam have unsatisfactory performance data. In particular, it is possible - if at all - only with quality losses of the extinguishing foam to vary the flowability of the extinguishing foam, so as to adapt, for example, the transportability by lines or to allow adjustment to the type of fire or the volume to be foamed. Often, no foam with defined properties or parameters can be generated.

On this basis, the present invention has the object, at least partially overcome the known from the prior art disadvantages.

These objects are achieved by the features of the independent claims. The respective dependent claims are directed to advantageous developments.

• – mindestens einen Mischungsanschluss zum Zuführen einer Mischung von Wasser und Schaummittel,
• – mindestens einen Gasanschluss zur Zuführung von unter Druck stehendem Gas und
• – mindestens einen Schlauchanschluss zum Abführen des Schaumes.

Die Verschäumungskammer umfasst weiterhin mindestens einen Wasseranschluss zur Zuführung von Wasser.The device according to the invention for providing a foam comprises a foaming chamber. The foaming chamber comprises

• At least one mixing port for supplying a mixture of water and foaming agent,
• - At least one gas connection for supplying pressurized gas and
• - At least one hose connection for discharging the foam.

The foaming chamber further comprises at least one water connection for supplying water.

The term foam is understood here in particular an extinguishing foam or fire-extinguishing foam. The term water is understood here in particular normal tap water, city water or process water. The term foaming agent is understood to mean, in particular, a foaming agent which is suitable for obtaining extinguishing foam and for which, where appropriate, official or official approvals are available. With the device according to the invention, all conventional foaming agents, including, for example, commercially available rinsing agent, can be processed for the production of extinguishing foam. Under a pressurized gas is understood to mean a gas whose pressure is higher than the ambient pressure. Preference is given to a process procedure in which a relaxation occurs on entering the expansion chamber and / or on exiting the expansion chamber and / or on exiting from a hose connected to the hose connection. In particular, the pressurized gas used is air, a gas comprising nitrogen and / or nitrogen. Preferably, the gas is at a pressure of at least 2 bar absolute, in particular at a pressure of 3 bar, more preferably from about 4 bar to about 6 bar absolute.

Due to the design of the water connection, it is possible to introduce water into the expansion chamber in addition to the mixture of water and foam. This makes it possible to vary the Verschäumungszahl the resulting foam. The expansion number is defined as the ratio of the amount of foam produced to the sum of the volume of water used to generate the foam and foaming agent. A foaming factor of 70 means that when using one liter of water and foaming agent, a foam volume of 70 liters is produced. Depending on the foaming number, the properties of the foam produced vary. If additional water is fed directly into the foaming chamber during operation through the water connection, the water sinks Foaming number, the resulting foam is heavier and more flowable at the same time. If no additional water is supplied during operation through the water connection, so only the foaming of the mixture of water and foaming agent by the compressed air in the Verschäumungskammer, so the foam is lighter, drier, but less flowable than with the addition of additional water to Verschäumungskammer.

Due to the design of the additional water connection for the direct supply of water into the foaming chamber, it is thus possible to use the corresponding device more variable, since it has been shown that different fire situations require different foams to extinguish. Depending on the local training, it may be necessary to transport the resulting foam over longer distances than in other cases. For example, it may be necessary for a machine, such as a screw conveyor, to be penetrated by the extinguishing foam in order to be able to extinguish an internal source of fire. In this case, it is more advantageous to use more fluid foam than in cases where, for example, a silo for storing material has to be covered with foam from above in order to extinguish a fire that exists there. The device according to the invention thus makes it possible to provide extinguishing foam for a different fire situation with a single device.

According to an advantageous embodiment of the device, a mixer for mixing water and foaming agent is formed, via which the mixture can be delivered to the mixing port, wherein the mixer comprises at least one Venturi nozzle.

Consequently, therefore, the mixer with the mixing port is connectable, for example via a corresponding line. A venturi nozzle is understood to mean, in particular, an element having a pipe section which can be traversed in a throughflow direction and in which the cross section initially narrows in the flow direction up to a region of the smallest cross section and then increases again. In this area of the smallest diameter, another line meets the pipe section, through which the second component is added during operation. In the present invention, water flows through a narrowing tube in operation, in the region of the smallest cross section, the foaming agent is supplied. With a venturi nozzle, the dynamic pressure in the region of the narrowest cross section is maximum and the static pressure is minimal. This results in a suction of the foaming agent and a good mixing of the water and the foaming agent.

According to a further advantageous embodiment of the device, the foaming chamber comprises a sieve element through which at least the mixture passes during operation.

An embodiment is preferred in which the sieve element covers an entire cross section of the foaming chamber, so that in operation it is absolutely necessary for at least the mixture to pass through the sieve element. In addition to the mixture, it is preferable if the gas entering the foaming chamber also passes through the sieve element, as well as any additional water to be supplied. This means that the sieve element is formed at a location and a size at which at least the passage of the mixture through the sieve element is ensured, preferably at a location and in a size that also the gas passing through the gas port and / or the Any water passing through the water connection must pass or pass through the sieve element. Preferably, the sieve element is designed so that it is fully acted upon in operation, but at least at least 80% or even at least 90% of its surface, and / or the mixture is evenly distributed when passing through the sieve.

A sieve element is understood to mean an element which has openings through which a fluid can pass. The sieve element may have a flat, convex or concave surface. A preferred embodiment is one in which the sieve element has a concave surface. With a concave surface of the screen element, it is advantageously possible to wet it with a nozzle substantially completely with the mixture to be foamed. In this case, the nozzle is in particular designed and aligned in such a way that the concave surface of the screen element can be virtually wetted from the inside. The opening angle of the nozzle or the angle of the nozzle, which includes the liquid passing through the nozzle during operation and the distance of the nozzle to the concave surface of the screen element are preferably chosen so that this as evenly as possible and at least 80% of the surface of the screen element by the mixture , Preferably at least 90% of the surface of the screen element is acted upon.

• – mindestens einem Mischungsanschluss zum Zuführen einer Mischung von Wasser und Schaummittel,
• – mindestens einem Gasanschluss zur Zuführung von unter Druck stehendem Gas und
• – mindestens einem Schlauchanschluss zum Abführen des Schaumes;

die sich dadurch auszeichnet, dass ein Mischer zur Mischung von Wasser und Schaummittel ausgebildet ist, über den die Mischung an den Mischungsanschluss abgebbar ist, wobei der Mischer mindestens eine Venturi-Düse umfasst und dass die Verschäumungskammer ein Siebelement umfasst, durch welches zumindest die Mischung im Betrieb hindurchtritt.According to a further aspect, an apparatus for providing a foam is proposed, comprising a foaming chamber

• At least one mixing port for supplying a mixture of water and foaming agent,
• - At least one gas port for supplying pressurized gas and
• - At least one hose connection for discharging the foam;

characterized in that a mixer for mixing water and foaming agent is formed, via which the mixture is deliverable to the mixing port, wherein the mixer comprises at least one Venturi nozzle and in that the foaming chamber comprises a sieve element through which at least the mixture in Operation passes.

According to an advantageous embodiment, the expansion chamber further comprises at least one water connection for supplying water.

The disclosed preferred embodiments can be combined with both described devices.

Preferred is an embodiment in which the sieve element has a mesh size of 0.1 millimeters to 5 millimeters. This mesh size has proved to be particularly advantageous, since on the one hand the pressure increase is justified by such a sieve and on the other hand, a good foaming is achieved.

In principle, it is preferred that the mixing connection comprises a nozzle which is designed so that at least 80% of the surface of the sieve element is subjected to the mixture during operation.

By applying the mixture as much as possible to the sieving element, good foaming of the mixture takes place with a relatively high foaming rate. Further preferred is an embodiment in which the nozzle has a uniform spray pattern, ie in particular the mass density per angle element of the spray pattern fluctuates at most by +/- 10% in operation.

• – der mindestens eine Gasanschluss; und
• – mindestens ein Wasseranschluss zum Zuführen von Wasser in die Verschäumungskammer

so abdeckt, dass im Betrieb ein durch das Element tretendes Medium durch das Vlieselement tritt.According to a further advantageous embodiment, a nonwoven element is formed, which at least one of the following elements

• - the at least one gas connection; and
• - At least one water connection for supplying water into the Verschäumungskammer

covers so that in operation a passing through the element medium passes through the nonwoven member.

By carrying out pressurized gas such as compressed air through a nonwoven member it comes to an equalization of the gas flow, so that it comes to a more uniform mixing of the gas with the mixture and thus to a further improvement of the foaming. The same applies to water, which passes through a water connection for supplying water into the Verschäumungskammer, this also can be made uniform by the passage in its flow and dissolved into small drops, which lead to a good foaming of the mixture with a change in the Verschäumungszahl. A nonwoven element is understood to be an element which is formed from a fleece, that is to say in particular has a porous structure, it being possible for media or fluids to pass into and through the pores of the fleece.

• – Bereitstellen von Wasser;
• – Bereitstellen von Schaummittel;
• – Mischen von Wasser und Schaummittel zu einer Mischung durch Einsatz einer Venturi-Düse;
• – Einbringen der Mischung in eine Verschäumungskammer;
• – Verschäumen der Mischung durch Einbringen eines unter Druck stehenden Gases in die Verschäumungskammer zu dem Schaum;
• – Entnahme des Schaumes aus der Verschäumungskammer,

wobei zumindest die Mischung ein Siebelement passiert.According to a further aspect of the present invention, a method for providing a foam is proposed which comprises the following steps:

• - Providing water;
• - Providing foaming agent;
• Mixing water and foaming agent into a mixture by using a Venturi nozzle;
• - introducing the mixture into a foaming chamber;
• Foaming the mixture by introducing a pressurized gas into the foaming chamber to the foam;
• Removal of the foam from the foaming chamber,

wherein at least the mixture passes through a sieve element.

Preferably, the method according to the invention can be used in the device according to the invention. The combination of using a Venturi nozzle to produce the mixture of water and foaming agent and passing at least the mixture through a sieve has been found to be particularly advantageous. As a result, high Verschäumungszahlen can be achieved with evenly produced foam and foam quality.

According to an advantageous development, water is additionally introduced into the foaming chamber. This can be done for example by a separate water connection in the Verschäumungskammer, it is also possible to bypass the mixer in which are mixed in a Venturi nozzle water and foaming agent into a mixture by a bypass, so that in addition to the introduced water in the mixer also water in the expansion chamber can be given. By entering additional water in the Verschäumungskammer the Verschäumungszahl can be varied. In particular, this affects the flowability of the resulting foam.

• – des unter Druck stehenden Gases und
• – des zusätzlichen Wassers

in die Verschäumungskammer durch ein Vlieselement.According to a further advantageous embodiment, the introduction of at least one of the following fluids takes place:

• - of the pressurized gas and
• - additional water

in the Verschäumungskammer by a nonwoven element.

According to a further embodiment, the mixture is sprayed onto the screen element, which is acted upon at least 80% of the surface of the screen element with the mixture.

The features listed individually in the claims can be combined with one another in any technologically meaningful manner and can be supplemented by explanatory facts from the description and details from the figures, wherein further embodiments of the invention are shown.

The invention and the technical environment are explained in more detail below with reference to the attached figures, without the invention being restricted to the exemplary embodiments and details shown there. They show schematically:

1 a foaming chamber;

2 an air supply; and

3 a device for providing a foam.

1 schematically shows a foaming chamber 1 in longitudinal section. This includes a mixing port 2 for supplying a mixture of water and foaming agent, several gas connections 3 for supplying pressurized gas, here compressed air at a pressure of at least 3 bar absolute with a mass flow of at least 900 liters per minute, and a water connection 4 for supplying water into the foaming chamber 1 ,

The foaming chamber 1 also has a hose connection 5 on, through which the resulting foam is discharged. To the hose connection 5 a corresponding hose, not shown, can be connected, through which the resulting foam can be made, for example as a fire-fighting foam to a fire. The foaming chamber 1 has a mixing room 6 on. Through the mixing connection 2 During operation, a mixture of water and foaming agent enters the mixing chamber 6 , Preferred is an embodiment in which the mass fraction of foaming agent can be predetermined, for example to a value between 2.5 or 3.5 mass%, in particular to a range of about 3 mass%. The mixing room 6 is in the flow direction of the mixture from the mixing port 2 seen before the mix connection 2 with a nonwoven element 7 provided, which is fixed on an unspecified carrier element, preferably a perforated carrier made of metal. Upstream of the nonwoven element 7 are the gas connections 3 and the water connection 4 , Now passes through the gas connections during operation 3 Compressed air, so the corresponding air flow through the nonwoven element 7 pressed and thus evened.

Downstream is the mixing room 6 through a sieve element 8th limited. The mixing connection 2 has a nozzle 9 on. This nozzle 9 is designed so that it occupies an area of at least 80% of the surface of the sieve element 8th charged with the mixture of water and foaming agent. Particularly preferred is an embodiment in which the nozzle 9 is designed as a full cone nozzle having a uniform filled spray cone. Due to the design of a concave sieve element 8th and the design of the nozzle 9 so that these are the entire inner surface 17 of the concave sieve element 8th applied to the mixture, a particularly good foaming result can be achieved.

In operation, the out of the nozzle 9 exiting mixture of water and foaming agent through the through the nonwoven member 7 incoming compressed air entrained and through the sieve 8th pressed and foamed. Optionally, through the water connection 4 Water in the foaming chamber 1 are entered, this reduces the expansion rate and the resulting foam becomes more fluid. The flow properties of this foam are therefore improved compared to a process procedure in which no additional water in the Verschäumungskammer 1 is introduced. This is particularly advantageous when the foam has to be transported a certain distance, for example when the fire is inside an apparatus.

2 schematically shows an air supply 10 , About fittings 11 can the air supply 10 with the corresponding mixing connections 2 the foaming chamber 1 get connected.

3 schematically shows a device 12 to provide a foam. This has the Verschäumungskammer 1 on. The mixing connection 2 is with a mixer 13 formed for mixing water and foaming agent. The mixer 13 is via a water supply 14 with water, in particular Löschwassser, supplied. Preferred is an operation in which the water in the water supply 14 with a pressure of at least 4 bar, preferably at least 6 bar. About a foam agent supply line 15 a foaming agent is added. For this purpose, the water supply 14 with a corresponding water network and the foam supply line 15 associated with a supply of foaming agent, for example a corresponding canister or container. The mixer 13 includes a venturi nozzle. In the area of the smallest diameter foaming agent is added here, so that this on the Schaummittelzuleitung 15 is sucked in automatically by the prevailing pressure conditions in the Venturi nozzle. There is a thorough mixing of water and foam, this is distributed substantially uniformly in the water. The corresponding mixture is then passed through the mixing port 2 in the foaming chamber 1 entered. The device 12 also has a bypass 16 on. By means of this bypass 16 can be a part of through the water supply 14 pouring water around the mixer 13 around directly into the foaming chamber 1 be guided. As a result, the Verschäumungszahl of the Verschäumungskammer 1 leaving foam and the foam flow.

The device 12 to provide a foam may preferably be used to provide extinguishing foam. The for the device 12 disclosed details and advantages can be applied to the corresponding method and apply and vice versa. Through the further water connection 4 for introducing water directly into the foaming chamber 1 the foam quality can be influenced in particular with regard to the foaming factor and the flowability of the foam. This is the device 12 can be used in a wide variety of situations.

LIST OF REFERENCE NUMBERS

1

foaming chamber

2

mix connection

3

gas connection

4

mains water supply

5

hose connection

6

mixing room

7

nonwoven member

8th

sieve

9

jet

10

air supply

11

connector

12

Device for providing a foam

13

mixer

14

water supply

15

Foam concentrate supply line

16

bypass

17

palm

Claims (12)

Contraption ( 12 ) for providing a foam, comprising a foaming chamber ( 1 ), with - at least one mixing port ( 2 ) for supplying a mixture of water and foaming agent, - at least one gas connection ( 3 ) for supplying pressurized gas and - at least one hose connection ( 5 ) for discharging the foam; characterized in that the foaming chamber ( 1 ) at least one water connection ( 4 ) for supplying water. Contraption ( 12 ) according to claim 1, wherein a mixer ( 13 ) is formed for mixing water and foaming agent, via which the mixture to the mixing port ( 2 ) is deliverable, wherein the mixer ( 13 ) comprises at least one venturi nozzle. Contraption ( 12 ) according to one of the preceding claims, in which the foaming chamber ( 1 ) a sieve element ( 8th ) through which at least the mixture passes during operation. Contraption ( 12 ) for providing a foam, comprising a foaming chamber ( 1 ), with - at least one mixing port ( 2 ) for supplying a mixture of water and foaming agent, - at least one gas connection ( 3 ) for supplying pressurized gas and - at least one hose connection ( 5 ) for discharging the foam; characterized in that a mixer ( 13 ) is formed to mix water and foaming agent over which the mixture is deliverable to the mixing port, wherein the mixer ( 13 ) comprises at least one Venturi nozzle and that the Verschäumungskammer ( 1 ) a sieve element ( 8th ) through which at least the mixture passes during operation. Contraption ( 12 ) according to claim 4, wherein the foaming chamber ( 1 ) at least one water connection ( 4 ) for supplying water. Contraption ( 12 ) according to claims 3 to 5, wherein the sieve element ( 8th ) has a concave surface. Contraption ( 12 ) according to claims 3 to 6, wherein the mixing port ( 2 ) a nozzle ( 9 ), which is designed so that at least 80% of the surface of the sieve element ( 8th ) are charged with the mixture. Contraption ( 12 ) according to one of the preceding claims, in which a nonwoven element ( 7 ) is formed, which at least one of the following elements - the at least one gas connection ( 3 ); and / or - at least one water connection ( 4 ) for supplying water into the foaming chamber ( 1 ) in such a way that in operation a medium passing through the element passes through the nonwoven element ( 7 ) occurs. A method of providing a foam, comprising the following steps - providing water; - Providing foaming agent; Mixing water and foaming agent into a mixture by using a Venturi nozzle; - introducing the mixture into a foaming chamber ( 1 ); Foaming the mixture by introducing a pressurized gas into the foaming chamber ( 1 ) to the foam; Removal of the foam from the expansion chamber ( 1 ), wherein at least the mixture is a sieve element ( 8th ) happens. Process according to claim 9, in which water is additionally introduced into the foaming chamber ( 1 ) is introduced. Method according to one of claims 9 or 10, wherein the introduction of at least one of the following fluids: - the pressurized gas and - the additional water in the Verschäumungskammer ( 1 ) by a nonwoven element ( 7 ) he follows. Method according to one of Claims 9 to 11, in which the mixture is applied to the sieve element ( 8th ) is sprayed so that at least 80% of the surface of the sieve element ( 8th ) are charged with the mixture.

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