CN115427115B - Device for producing a gas-liquid mixture for fire-fighting purposes - Google Patents
Device for producing a gas-liquid mixture for fire-fighting purposes Download PDFInfo
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- CN115427115B CN115427115B CN202180028587.5A CN202180028587A CN115427115B CN 115427115 B CN115427115 B CN 115427115B CN 202180028587 A CN202180028587 A CN 202180028587A CN 115427115 B CN115427115 B CN 115427115B
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- mixing
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- gas
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- 239000007788 liquid Substances 0.000 title claims abstract description 133
- 239000000203 mixture Substances 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 claims abstract description 18
- 239000012530 fluid Substances 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 3
- 239000006260 foam Substances 0.000 description 21
- 239000003570 air Substances 0.000 description 9
- 239000012080 ambient air Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000004088 foaming agent Substances 0.000 description 4
- 239000004604 Blowing Agent Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 2
- 239000004480 active ingredient Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000003380 propellant Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C5/00—Making of fire-extinguishing materials immediately before use
- A62C5/02—Making of fire-extinguishing materials immediately before use of foam
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C13/00—Portable extinguishers which are permanently pressurised or pressurised immediately before use
- A62C13/66—Portable extinguishers which are permanently pressurised or pressurised immediately before use with extinguishing material and pressure gas being stored in separate containers
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C35/00—Permanently-installed equipment
- A62C35/02—Permanently-installed equipment with containers for delivering the extinguishing substance
- A62C35/023—Permanently-installed equipment with containers for delivering the extinguishing substance the extinguishing material being expelled by compressed gas, taken from storage tanks, or by generating a pressure gas
Landscapes
- Health & Medical Sciences (AREA)
- Public Health (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Nozzles (AREA)
- Accessories For Mixers (AREA)
Abstract
An apparatus configured to produce a gas-liquid mixture for fire fighting purposes is disclosed. The apparatus includes a mixing vessel configured to receive a liquid medium and a pressurized gaseous medium, wherein the mixing vessel has an outlet for a gas-liquid mixture and a mixing conduit disposed within the mixing vessel and configured to direct the gas-liquid mixture toward the vessel outlet. The mixing conduit includes a wall having a mixing channel configured to introduce a gaseous medium into the liquid medium from outside the mixing conduit as the liquid medium is directed within the mixing conduit toward the container outlet. The mixing channel has a first cross-sectional area and the portion of the mixing conduit downstream of the mixing channel or the portion of the discharge line downstream of the mixing conduit has a second cross-sectional area. The ratio of the first cross-sectional area to the second cross-sectional area is between 1:4 and 1:25. A fire protection method using the apparatus presented herein is also disclosed.
Description
Technical Field
The present disclosure relates generally to the field of fire protection. In particular, an apparatus for producing a gas-liquid mixture for fire fighting purposes is proposed, wherein the gas-liquid mixture is a mixture of a liquid medium and a pressurized gaseous medium.
Background
In the fire-fighting field, different fire-fighting techniques are used depending on the source and intensity of the fire. Since the 90 s of the 20 th century, compressed Air Foam System (CAFS) technology has been increasingly used.
Conventional (non-compressed) air foam systems use ambient air to create fire fighting foam. For this purpose, ambient air is sucked into the jet pump of the fire-fighting equipment and supplied to the mixture of water and foaming agent. CAFS, on the other hand, does not use ambient air to create fire fighting foam. Alternatively, pressurized air is introduced into the liquid medium (i.e., the water/blowing agent mixture). The advantage of using pressurized air is that energy losses due to sucking ambient air into the jet pump and mixing the ambient air into the liquid medium are avoided. As a result, CAFS generally has a longer jet range than systems that use ambient air to generate fire fighting foam.
CAFS may be utilized in different configurations. They may be mounted in a fixed manner, for example in a building, or permanently mounted on a fire engine, or they may be used as portable fire protection equipment. In the case of fixed and permanently installed CAFSs, the system can become very complex. Such systems typically can adjust operating parameters such as the mixing ratio of pressurized air to liquid medium and the air pressure during actuation. Portable CAFSs, on the other hand, typically have fixed operating parameters, which enable quick and untrained use.
In portable CAFS with fixed operating parameters, the design of the system in terms of geometrical and operating parameters is decisive for its application area and the extinguishing effect of the fire fighting foam produced. As such, system design may become challenging in view of the partially different requirements.
The usual method of mixing pressurized air with a liquid medium utilizes special mixing equipment, such as a dedicated pump arrangement or mixing chamber. Pressurized air and a liquid medium, typically a mixture of water and a foaming agent, are introduced into the mixing device via two separate ports and mixed therein. In this regard, US 6,543,547B2 discloses a portable fire fighting device that utilizes a mixing chamber that is arranged directly in front of a fire extinguisher gun that acts as a nozzle. A double hose or two separate hoses are used to introduce the pressurized gas and the extinguishing medium into the mixing chamber, respectively.
The known CAFS with mixing chambers have the disadvantage of complex design, high material and maintenance costs.
US 5,992,530A discloses an arrangement for extinguishing a fire in a space. The arrangement comprises a spray head of a type which is capable of producing a finely divided extinguishing medium in the form of a liquid mist, while at the same time producing suction in the vicinity of the spray head.
WO 98/09683A1 discloses a fire fighting equipment comprising a hydraulic accumulator. The hydraulic accumulator comprises at least one pressure vessel having a space for a fire extinguishing liquid, a space for a propellant gas and a riser arranged within the pressure vessel. The riser pipe is provided with at least one side opening and has a feed opening in the lower part of the pressure vessel for feeding extinguishing liquid to the riser pipe and further to the at least one nozzle. The riser pipe also has a throttle valve in the region below the uppermost opening. The one or more side openings are located in the riser such that in an initial fire fighting situation, only liquid flows through the riser until the liquid sinks to a level below the side openings, after which the gas starts to mix into the liquid.
DE 20 2014 010 053 U1 discloses a device for producing fire-fighting foam or active ingredient foam. The apparatus includes a pressure vessel for receiving a liquid. The pressure vessel includes a vessel bottom, a vessel top, and vessel walls extending between the vessel bottom and the vessel top. The apparatus also includes a transfer conduit extending between the vessel base and the vessel top of the pressure vessel. When this arrangement is used as intended, the transfer tube transfers the liquid provided in the pressure vessel from a region near the bottom of the vessel to the outlet opening at the top of the vessel by pressurizing the region of the pressure vessel arranged above the liquid level with a pressurized gas. There are gas supply means for supplying or injecting pressurized gas into the transfer conduit from a region of the pressure vessel arranged above the liquid level during transfer of the liquid through the transfer conduit.
Disclosure of Invention
There is a need for an apparatus for producing a gas-liquid mixture for fire fighting purposes that has a simple and cost effective design while providing preferred fire fighting characteristics.
An apparatus configured to produce a gas-liquid mixture for fire fighting purposes is provided. The apparatus includes a mixing vessel configured to receive a liquid medium and a pressurized gaseous medium, wherein the mixing vessel has an outlet for a gas-liquid mixture and a mixing conduit disposed within the mixing vessel and configured to direct the gas-liquid mixture toward the vessel outlet. The mixing duct includes a wall having a mixing channel configured to introduce a gaseous medium into the liquid medium from outside the mixing duct as the liquid medium is directed within the mixing duct toward the container outlet, wherein the mixing channel has a first cross-sectional area and a portion of the mixing duct downstream of the mixing channel or a portion of the discharge line downstream of the mixing duct has a second cross-sectional area. The ratio of the first cross-sectional area to the second cross-sectional area is between 1:4 and 1:25.
According to one implementation, the mixing channel is defined by one or more mixing holes. The mixing holes may be arranged linearly one after the other along the longitudinal axis of the container. The first cross-sectional area may be defined by the total cross-sectional area of the one or more mixing holes. The mixing holes may have different shapes (circular, rectangular, etc.). For example, the mixing holes may be internal holes drilled into the mixing pipe.
The first cross-sectional area of the mixing channel may be at least one of greater than 3mm 2 and less than 13mm 2. The first cross-sectional area may in particular be at least one of greater than 4.5mm 2 and less than 9.1mm 2. Further, the first cross-sectional area of the channel may be at least one of greater than 5.1mm 2 and less than 7.1mm 2. The use of different sized first cross-sectional areas results in different mixing ratios of pressurized gaseous medium to liquid medium when the device is actuated at the same pressure.
The mixing vessel may include a vessel bottom opposite the vessel outlet and defining a longitudinal extension from the vessel bottom to the vessel outlet. The total height of the mixing vessel may be between 200mm and 800mm, in particular between 300 and 600 mm. The mixing vessel may be substantially cylindrical along the longitudinal extension. The cross-sectional area of the mixing vessel at the longitudinal extension may have a diameter of between 100mm and 300mm, in particular between 150mm and 200 mm. The first distance between the mixing channel and the bottom of the container along the longitudinal extension may be at least 5 times, in particular at least 8 times (e.g. more than 10 times) the second distance between the mixing channel and the outlet of the container along the longitudinal extension. The first distance may be up to 30 times, in particular up to 20 times (e.g. up to 15 times), the second distance. Placing the mixing channel near the outlet of the container, rather than near the bottom of the container, ensures that the mixing channel is located above the level of the liquid medium so that the pressurized gaseous medium can flow properly through the mixing channel.
The second cross-sectional area may be the smallest cross-sectional area of a fluid passage of a mixture of liquid medium and pressurized gaseous medium from the mixing passage to a portion of the mixing conduit downstream of the mixing passage or to a portion of the discharge line downstream of the mixing conduit. In particular, the second cross-sectional area may be a cross-sectional area immediately downstream of the mixing channel end (e.g., a point adjacent to the mixing aperture closest to the container outlet). In this way, the mixture of pressurized gaseous medium and liquid medium will not be restricted in the section downstream of the mixing channel and a constant and stable flow of the mixture can be established. According to one embodiment, the second cross-sectional area is at least one of greater than 28mm 2 (e.g., greater than 40mm 2) and less than 133mm 2 (e.g., less than 60mm 2). The mixing duct may have a diameter greater than 3mm (e.g., greater than 6 mm) and less than 13mm (e.g., less than 10 mm).
The mixing duct may have a third cross-sectional area in the region of the mixing channel. In particular, the third cross-sectional area is defined by the cross-sectional area of the mixing conduit at the point in the mixing conduit where the pressurized gaseous medium is first introduced into the liquid medium (e.g., at the beginning of the first bore through which the liquid medium passes as the liquid medium flows within the mixing conduit toward the outlet of the container). The ratio between the first cross-sectional area and the third cross-sectional area may be greater than or equal to the ratio between the first cross-sectional area and the second cross-sectional area. In this way, the flow of liquid medium towards the mixing vessel outlet will not be restricted at the mixing channel and the mixing ratio of the two media can be kept constant during actuation of the device.
The mixing duct may have a straight extension from a first end located near the container outlet to a second end located near the bottom of the container opposite the container outlet. The length of the straight extension may be between 150mm and 750mm, in particular between 300mm and 600mm (e.g. between 400mm and 500 mm). The second end may have a different shape. For example, it may be curved or pointed in order to ensure that the liquid medium can flow into the mixing duct in an unobstructed manner. When the second end portion is bent, it may have a concave portion formed in a semicircle. The diameter of the semicircle may be related to the inner diameter of the mixing pipe. The diameter may be between 1mm and 12mm, in particular between 4mm and 9 mm. The inner diameter of the mixing pipe may be between 5mm and 25mm, in particular between 10mm and 20 mm.
The volume of the mixing vessel may be between 3 liters and 500 liters (e.g., between 8 liters and 30 liters). The mixing vessel can withstand pressures up to between at least 3 bar and 15 bar (e.g., up to between at least 3 bar and 30 bar). The working temperature of the mixing vessel may be between-40 ℃ and 80 ℃, in particular between-35 ℃ and 70 ℃.
The apparatus may also include a nozzle configured to discharge the gas-liquid mixture from the apparatus. The nozzle may be a conventional nozzle known in the fire protection art and may allow for controlled and untrained use of the device. The apparatus may also include a control valve configured to control the discharge of the gas-liquid mixture. A control valve may be located between the discharge line and the mixing conduit to control the pressure on the discharge line.
The apparatus may include a pressure tank configured to store a pressurized gaseous medium and a pressure line extending from the pressure tank to the mixing vessel. In this way, the pressure tank may act as a source of pressurized gaseous medium. The pressure tank may be (e.g., detachably) connected to the container. The pressure tank is capable of withstanding pressures up to between at least 200 bar and 450 bar. The volume of the pressure tank may be between 0.5 and 10 litres, in particular between 1 and 3 litres. The pressure tank may include a tank bottom opposite the tank outlet and define a longitudinal extension from the tank bottom to the tank outlet. The total height of the pressure tank may be between 200mm and 800mm, in particular between 300mm and 400 mm. The pressure tank may be substantially cylindrical along the longitudinal extension. The cross-sectional area of the mixing vessel at the longitudinal extension may have a diameter of between 40mm and 200mm, in particular between 60mm and 100 mm. The total height of the pressure tank may be between 100mm and 600mm, in particular between 250mm and 450 mm. Furthermore, the apparatus may include at least one restrictor valve located between the pressure line and the outlet of the pressure tank and configured to controllably release the pressurized gaseous medium from the pressure tank into the mixing vessel. As a result, the pressure within the mixing vessel may remain constant during actuation of the device. For example, during actuation of the device, the pressure within the mixing vessel may be adjusted to a range between 7 bar and 10 bar (e.g., to about 8.5 bar).
The gas-liquid mixture may be a foam, especially when the liquid medium stored in the mixing vessel is a mixture of water and a foaming agent. The fire fighting characteristics of the foam produced by mixing a pressurized gaseous medium with a liquid medium may depend on the bubble size of the foam produced, for example, because different bubble sizes result in different ranges of fire fighting jets. With this device, the bubble size of the generated foam can be controlled via the mixing ratio of the pressurized gaseous medium to the liquid medium and the pressure of the discharge mixture.
The pressure tank may be located outside the mixing vessel. For example, the pressure tank may be located near the mixing vessel. The pressure tank may be attached to the mixing vessel (e.g., in a detachable manner).
At least 70%, in particular at least 80% (e.g. 90% or more) of the volume defined by the mixing vessel may be filled with liquid medium. The mixing channel may be located in a wall of the mixing conduit such that the mixing channel (e.g. each or one or more mixing holes) is located above the level of the liquid medium when at least 70%, in particular at least 80% (e.g. 90% or more) of the volume defined by the mixing vessel is filled with the liquid medium.
A fire method using an apparatus having a first cross-sectional area with the geometric design parameters set forth herein, for example, between 3mm 2 and 13mm 2, is also provided. The method may use any of the operating parameters set forth herein, such as maintaining a pressure within the mixing vessel in a range between 7 bar and 10 bar.
The method aims to produce a gas-liquid mixture for fire fighting purposes with the device presented herein, wherein a liquid medium is received in a mixing vessel of the device. The method comprises introducing a pressurized gaseous medium into the mixing vessel, introducing the pressurized gaseous medium into the liquid medium from outside the mixing conduit via a mixing channel comprised by the wall of the mixing conduit, and directing the gas-liquid mixture from the mixing channel towards the vessel outlet, as the liquid medium is directed in the mixing conduit towards the vessel outlet.
The method may include discharging the gas-liquid mixture from a nozzle of the apparatus.
The method may include providing pressurized gaseous medium from a pressure tank to a mixing vessel.
The pressure in the mixing vessel may remain substantially constant during actuation of the apparatus to produce the gas-liquid mixture. By maintaining a constant pressure within the mixing vessel during actuation of the device, in some variations, the mixing ratio of gaseous medium to liquid medium may be maintained substantially constant during actuation of the device, particularly when the mixing channel is maintained above the fluid level throughout actuation. The mixing ratio of the pressurized gaseous medium to the liquid medium may be between 30:1 and 70:1 parts by volume, in particular between 40:1 and 60:1 parts by volume (for example, about 50:1 parts by volume).
Drawings
Further features and advantages of the device presented herein are described below with reference to the attached drawings, wherein:
FIG. 1 illustrates a schematic view of a first embodiment of an apparatus configured to produce a gas-liquid mixture for fire fighting purposes, the apparatus including a mixing vessel and a mixing conduit;
FIG. 2 illustrates a schematic view of a closure assembly including the mixing conduit, control valve, and closure for the mixing vessel outlet of FIG. 1;
FIG. 3 illustrates a schematic view of a fully operational fire fighting apparatus including the apparatus of FIG. 1, the closure assembly of FIG. 2, and further including a discharge line and a nozzle;
FIG. 4 illustrates a schematic view of a second embodiment of an apparatus configured to produce a gas-liquid mixture for fire fighting purposes, the apparatus including an inlet for a pressurized gaseous medium;
FIG. 5 illustrates a schematic view of an alternative closure assembly for the mixing vessel of FIG. 4;
FIG. 6 illustrates a schematic view of the combination of the apparatus of FIG. 4, the closure assembly of FIG. 5, and a pressure tank;
FIG. 7 illustrates a schematic view of a second fully operational fire apparatus including the assembly of FIG. 6, a discharge line, and a nozzle; and
Fig. 8 illustrates a flow chart of a method of producing a gas-liquid mixture for fire fighting purposes using the apparatus presented herein.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent to one skilled in the art that the present disclosure may be practiced in other embodiments that depart from these specific details.
Fig. 1 illustrates a schematic view of an embodiment of an apparatus 50 configured to produce a gas-liquid mixture for fire fighting purposes. The device 50 is suitable for use as a CAFS. As such, compressed air may be used as a pressurized gaseous medium that is introduced into a liquid medium to produce a gas-liquid mixture. The liquid medium may be a mixture of water and a foaming agent, commonly used for fire fighting purposes.
The apparatus 50 includes a mixing vessel 100, the mixing vessel 100 configured to receive a liquid medium and a pressurized gaseous medium. The mixing vessel 100 has an outlet 110 for the gas-liquid mixture, the outlet 110 being located at the top end of the vessel 100.
Mixing vessel 100 also includes a vessel bottom 112 opposite vessel outlet 110. A longitudinal extension of the container 100 is defined from the container bottom 112 to the container outlet 110. The mixing vessel 100 in this embodiment has a volume of about 4 liters to 15 liters (e.g., about 6 liters). In different embodiments, the mixing vessel 100 may have different sizes and thus may have different volumes, for example between 3 and 500 liters. The mixing vessel 100 is capable of withstanding pressures up to at least 3 bar. Depending on its size and weight, the device 50 may be a portable device or a stationary device and may be combined with a trolley or fire truck (not shown in fig. 1).
The apparatus 50 illustrated in fig. 1 further includes a mixing conduit 120, the mixing conduit 120 being shown disposed within the mixing vessel 100. The mixing conduit 120 extends straight from a first end 122 at the vessel outlet 110 to a second end 124 near the vessel bottom 112 opposite the vessel outlet 110 and is configured to direct the gas-liquid mixture toward the vessel outlet 110. The second end 124 illustrated in fig. 1 is pointed so that the liquid medium may flow into the mixing tube 120 in an unobstructed manner.
The mixing duct 120 comprises a wall with a mixing channel 130. The mixing channel 130 is configured to introduce a gaseous medium into the liquid medium from outside the mixing conduit 120 as the liquid medium is directed within the mixing conduit 120 towards the vessel outlet 110, thereby generating a gas-liquid mixture. The first distance d1 along the longitudinal extension between the mixing channel 130 and the container bottom 112 is greater than the second distance d2 along the longitudinal extension between the mixing channel 130 and the container outlet 100. For example, the first distance d1 may be at least 5 times, in particular at least 8 times, the second distance d2. The mixing channel 130 is placed near the vessel outlet 110 instead of near the vessel bottom 112 to ensure that the mixing channel 130 is above the level of the liquid medium so that the pressurized gaseous medium can flow properly through the mixing channel 130.
The mixing channel 130 exemplarily illustrated in fig. 1 is defined by a single mixing hole 130. Additional mixing holes are optional and are indicated by dashed circles in fig. 1. In fig. 1, the mixing holes 130 are disposed between two optional holes located along the longitudinal extension of the mixing duct 120. Thus, the three holes are arranged linearly one after the other. Additionally or alternatively, as shown in fig. 1, two or more mixing holes may be arranged in the circumferential direction of the mixing duct 120. The mixing channel 130 has a first cross-sectional area a 1 and the portion of the mixing duct 120 downstream of the mixing channel 130 or the portion of the optional discharge line 140 (see fig. 2) downstream of the mixing duct 120 has a second cross-sectional area a 2. The ratio between the first cross-sectional area a 1 and the second cross-sectional area a 2 is between 1:4 and 1:25, in particular between 1:7 and 1:11. In this example, the first cross-sectional area a 1 is defined by the cross-sectional area of the single mixing hole 130.
If there are a plurality of mixing holes, the first cross-sectional area A 1 is defined by the total cross-sectional area of the plurality of mixing holes. The mixing holes may have different forms and shapes as long as the above-described ratio between the first cross-sectional area a 1 and the second cross-sectional area a 2 is satisfied. In one example, the mixing holes are internal holes disposed in the mixing conduit.
Fig. 2 illustrates a schematic diagram of a closure assembly including a mixing conduit 120 (similar to the mixing conduit in fig. 1), a control valve 150, and a closure for the mixing vessel outlet 110.
In the embodiment of fig. 2, the mixing channel 130 of the mixing duct 120 is defined by a single mixing hole 130 having a diameter of about 2.7 mm. Thus, the first cross-sectional area a 1 is about 5.7mm 2. The diameter of the portion of the discharge line 140 shown in fig. 2 is about 8mm. Thus, the second cross-sectional area A2 is about 50.3mm2. Thus, the ratio of the first cross-sectional area to the second cross-sectional area A2 illustrated in FIG. 2 is about 1:9. When other operating parameters, such as the pressure of the gaseous medium in the mixing vessel 100, are kept unchanged, a change in this ratio will lead to different results when discharging a mixture of pressurized gaseous medium and liquid medium. For example, a reduction in the size of the first cross-sectional area a 1 to 1.8mm 2 (corresponding to a single mixing hole 130 of 1.5mm diameter) would result in a ratio between the first cross-sectional area a 1 and the second cross-sectional area a 2 of approximately 1:28. This ratio variation results in a higher concentration of liquid medium in the mixture, which may further result in that not all of the blowing agent included in the liquid medium is used to generate foam and is therefore wasted.
In other embodiments, the first cross-sectional area a 1 of the mixing channel is between 3mm 2 and 13mm 2. In particular, the first cross-sectional area a 1 is between 4.5mm 2 and 9.1mm 2. In another embodiment, the first cross-sectional area a 1 of the channel is between 5.1mm 2 and 7.1mm 2. According to these examples, the second cross-sectional area a 2 is between 28mm 2 and 133mm 2 so as to provide a ratio of the first to second cross-sectional areas a 1:A2 between 1:4 and 1:25.
The mixing duct 120 has a third cross-sectional area a 3 in the region of the mixing channel 130. The ratio between the first cross-sectional area a 1 and the third cross-sectional area a 3 is greater than or equal to the ratio between the first cross-sectional area a 1 and the second cross-sectional area a 2. Thus, the flow of liquid medium towards the outlet 110 of the mixing vessel 100 will not be restricted at the mixing channel 130.
The control valve 150 illustrated in fig. 2 is configured to control the discharge of the gas-liquid mixture. The control valve 150 may be a conventional controllable check valve that, when actuated, allows the discharge of the mixture, otherwise prevents the discharge of the mixture.
Fig. 3 illustrates a schematic diagram of a fully operational fire apparatus 300. The fire apparatus 300 combines the features discussed above with reference to fig. 1 and 2, and further includes the discharge line 140 and the nozzle 160.
In the embodiment of fig. 3, the discharge line 140 is located downstream of the mixing duct 120, and the control valve 150 is located between the discharge line 140 and the mixing discharge duct 120. When the control valve 150 is not actuated, the drain line 140 is not under pressure. This extends the life of the discharge line 140 and increases the overall safety, as a damaged discharge line 140 does not automatically lead to a discharge of the mixture of pressurized gaseous medium and liquid medium. Furthermore, since the mixing of the pressurized gaseous medium with the liquid medium takes place upstream of the outlet 110 of the mixing vessel 100, the discharge line 140 may for example be a simple hose commonly used with fire extinguishers. Such a complex and more expensive structure as a double hose is not required.
The nozzle 160 is configured to operate as a check valve, similar to the control valve 150, and to discharge the gas-liquid mixture from the fire apparatus 300 upon actuation of the nozzle 160. The nozzle 160 may be a nozzle well known in the fire fighting arts. Due to the combination of the control valve 150 and the nozzle 160, actuation of the control valve 150 results in the mixture of pressurized gaseous medium and liquid medium flowing into the discharge line 140. The nozzle 160 is then actuated causing the mixture to be discharged from the nozzle 160. Thus, actuation of both control valve 150 and nozzle 160 results in a constant discharge of the mixture from nozzle 160 at the actuation time until the liquid medium is completely discharged or until the gaseous medium initially stored in mixing vessel 100 is no longer sufficiently pressurized.
With respect to the flow path of the fluid mixture represented by the arrows in fig. 3, the second cross-sectional area a 2 is the smallest cross-sectional area of the flow path from the mixing path 130 to the portion of the mixing duct 120 downstream of the mixing path 130 and the portion of the discharge line 140 downstream of the mixing duct 120. Thus, the mixture of pressurized gaseous medium and liquid medium will not be restricted in the section downstream of the mixing channel 130 and a constant and stable flow of the mixture may be established.
Fig. 4 illustrates a schematic diagram of a second embodiment of an apparatus 50 configured to produce a gas-liquid mixture for fire fighting purposes.
In the embodiment of fig. 4, the apparatus 50 includes a mixing vessel 100, a mixing conduit 120, and an inlet 170 for gas. The mixing vessel 100 and mixing tube 120 have the same features as illustrated in fig. 1. The inlet 170 for pressurized gaseous medium is configured such that a source of pressurized gaseous medium may be fluidly coupled to the inlet 170. When a pressurized gaseous medium source is coupled to inlet 170, the pressure within mixing vessel 100 may remain constant during actuation of device 50. This results in foam generated during actuation of the device 50 having consistent fire characteristics. The source may be a portable source such as a well known portable gas container. The source may also be a fixed mounted source, such as a source that may be mounted in a building or on a fire truck.
Fig. 5 illustrates a schematic view of an alternative closure for the mixing container 100 of fig. 4. Here, a possible flow of pressurized gaseous medium is indicated by arrows.
Fig. 6 illustrates a schematic view of the combination of the apparatus 50 of fig. 4, the closure assembly of fig. 5, and the pressure tank 200.
In the embodiment of fig. 6, pressure tank 200 is configured to store pressurized gaseous medium. A pressure line 210 extends from the pressure tank 200 to the mixing vessel 100. In addition, a restrictor valve 220 is located between the pressure line and an outlet 230 of the pressure tank 200. The restrictor valve 220 is configured to controllably release pressurized gaseous medium from the pressure tank 200 into the mixing vessel 100. The restrictor valve 220 may be a conventional controllable check valve. In this example, pressure tank 200 is configured as a source of pressurized gaseous medium and can withstand pressures up to between at least 200 and 450 bar. Accordingly, the pressure tank 200 is configured to have a smaller volume as compared to the mixing tank 100. As a result, the illustrated combination of mixing vessel 100 and pressure tank 200 may still be configured to be portable.
Fig. 7 illustrates a schematic view of a second fully operational fire apparatus 350, the fire apparatus 350 including the assembly of fig. 6, the discharge line and the nozzle. The device 350 incorporates all of the features described above with reference to fig. 4-6.
Actuation of restrictor valve 220 causes pressurized gaseous medium to flow from pressure tank 200 through pressure line 210 to mixing vessel 100. Additional actuation of the control valve 150 causes gaseous medium to flow into the liquid medium through the mixing channel 130 and causes the liquid medium to flow toward the outlet 110 of the mixing vessel 100. The pressure of the gaseous medium in the mixing vessel 100 may be maintained at about 8.5 bar. The mixture of pressurized gaseous medium and liquid medium flows into discharge line 140 and to nozzle 160. Additional actuation of the nozzle 160 then also results in a constant and stable discharge of the generated foam with consistent fire characteristics over the actuation time or prior to discharge of the liquid medium. Forming a mixture of pressurized gaseous medium and liquid medium at a constant mixing ratio during actuation enables reliable fire protection.
The fire fighting characteristics of the foam produced by utilizing one of the fully operational fire fighting devices 300, 350 of fig. 3 and 7 may be controlled via the mixing ratio of the pressurized gaseous medium to the liquid medium and via the pressure of the discharge mixture. Thus, with respect to one type of blowing agent, the combination of the cross-sectional area and the pressure of the pressurized gaseous medium within the mixing vessel 100 determines the characteristics of the foam produced. For example, if the ratio of the first cross-sectional area a 1 to the second cross-sectional area a 2 is high (e.g., 1:3 or higher), the discharged mixture will contain so much pressurized gaseous medium that the resulting jet of discharged medium will be discontinuous. For example, if the ratio of the first cross-sectional area a 1 to the second cross-sectional area a 2 is low (e.g., 1:28 and lower), the discharged mixture will contain so much liquid medium that the resulting foam is not uniform. Furthermore, the pressure of the gaseous medium within the mixing vessel 100 affects the size of the foam bubbles and the extent of the resulting jet. In general, higher pressures result in smaller bubbles and a longer range of the resulting jet. At the same time, higher pressures increase the likelihood of turbulence in the resulting jet. Turbulence can result in uncontrolled jets. Thus, finding a pressure that produces the longest range of controllable jets without turbulence may be regarded as an optimization problem. The ratio of the first and second cross-sectional areas a 1:A2 is between 1:4 and 1:25, in particular between 1:7 and 1:11, in combination with the gaseous medium pressure within the mixing vessel 100 between 3 bar and 15 bar, in particular between 8 bar and 9 bar, results in a constant discharge of uniform foam, and a high range of the resulting jet.
In the embodiments discussed above, by directing the gas-liquid mixture within the mixing conduit 120 disposed within the mixing vessel 100 toward the vessel outlet 110, a constant discharge of uniform foam is produced, with the resulting jet having a high extent. To produce a gas-liquid mixture, pressurized gaseous medium is introduced into the liquid medium from outside the mixing conduit 120 via mixing channels 130 comprised by the walls of the mixing conduit 120 as the liquid medium is directed within the mixing conduit 120 towards the vessel outlet 110. The mixing channel 130 has a first cross-sectional area A1. The portion of the mixing conduit 120 downstream of the mixing channel 130 or the portion of the discharge line 140 downstream of the mixing conduit 120 has a second cross-sectional area A2. The ratio of the first and second cross-sectional areas A1 to A2 is between 1:4 and 1:25, in particular between 1:7 and 1:11. The pressure of the gaseous medium inside the mixing vessel 100 is between 3 and 15bar, in particular between 7 and 10 bar (for example between 8 and 9 bar).
Fig. 8 shows a flow chart 400 of a method of producing a gas-liquid mixture for fire fighting purposes using the apparatus 50 described above, wherein a liquid medium is received in the mixing vessel 100 of the apparatus 50. In one embodiment, the mixing vessel 100 has been filled with an amount of liquid medium such that at least 70% of the volume defined by the mixing vessel 100 is filled with liquid medium. The mixing channel 130 is located in the wall of the mixing conduit 120 such that during normal use of the device 50, the mixing channel 130 is located above the level of the liquid medium within the mixing vessel 100 during the overall actuation of the device 50.
In step 410, pressurized gaseous medium is introduced from pressure tank 200 into mixing vessel 100. The introduction of the gaseous medium into the mixing vessel 100 may be accomplished in a controlled manner, for example, by adjusting the restrictor valve 220 accordingly, as described above in connection with fig. 6 and 7.
In step 420, a pressurized gaseous medium is introduced into the liquid medium via the mixing channel 130. The geometrical design parameters of the apparatus 50, such as the first cross-sectional area between 3mm 2 and 13mm 2, and the operating parameters, such as maintaining the pressure within the mixing vessel in the range between 7 bar and 10 bar, may be selected such that the mixing ratio of the pressurized gaseous medium to the liquid medium is between 30:1 and 70:1 parts by volume, in particular between 40:1 and 60:1 parts by volume (e.g. about 50:1 parts by volume).
In step 430, the gas-liquid mixture is directed within mixing conduit 120 toward vessel outlet 110.
In other words, the liquid medium enters the mixing duct at the second end 124 of the mixing duct 120 near the bottom 112 of the container and flows upward toward the mixing channel 130. The pressurized gaseous medium is introduced into the liquid medium via the mixing channel 130, and the resulting mixture is then directed towards the container outlet 110.
In some variations, the combination of geometric design parameters of the apparatus 50 can allow for the discharge of a continuous jet of a uniform mixture of liquid medium and pressurized gaseous medium from the apparatus 50. In particular, by (i) defining a mixing channel 130 above the liquid level and having a first cross-sectional area a 1, (ii) defining a portion of the mixing conduit 120 downstream of the mixing channel 130 or a portion of the discharge line 140 downstream of the mixing conduit 120 having a second cross-sectional area a 2, and (iii) defining a ratio between the first cross-sectional area a 1 and the second cross-sectional area a 2 of between 1:4 and 1:25, a continuous jet of a homogeneous mixture of liquid medium and pressurized gaseous medium can be allowed to drain from the apparatus 50.
Claims (22)
1. An apparatus (50) configured to produce a gas-liquid mixture for fire fighting purposes, the apparatus (50) comprising:
-a mixing vessel (100), the mixing vessel (100) being configured to receive a liquid medium and a pressurized gaseous medium, wherein the mixing vessel (100) has a vessel outlet (110) for the gas-liquid mixture;
a mixing conduit (120), the mixing conduit (120) being arranged within the mixing vessel (100) and configured to direct the gas-liquid mixture towards the vessel outlet (110),
-Wherein the mixing duct (120) comprises a wall with a mixing channel (130), the mixing channel (130) being configured to introduce the pressurized gaseous medium into the liquid medium from outside the mixing duct (120) when the liquid medium is directed within the mixing duct (120) towards the container outlet (110), and wherein the mixing channel (130) has a first cross-sectional area (a 1), and wherein (i) the part of the mixing duct (120) downstream of the mixing channel (130) has a second cross-sectional area (a 2) or (ii) the part of the discharge line (140) downstream of the mixing duct (120) has a second cross-sectional area (a 2), and wherein the ratio between the first cross-sectional area (a 1) and the second cross-sectional area (a 2) is between 1:4 and 1:25,
Wherein the mixing vessel (100) comprises a vessel bottom (112) opposite the vessel outlet (110) and defines a longitudinal extension from the vessel bottom (112) to the vessel outlet (110), and wherein a first distance between the mixing channel (130) and the vessel bottom (112) along the longitudinal extension is at least 5 times a second distance between the mixing channel (130) and the vessel outlet (110) along the longitudinal extension.
2. The apparatus (50) of claim 1, wherein a first distance along the longitudinal extension between the mixing channel (130) and the container bottom (112) is at least 8 times a second distance along the longitudinal extension between the mixing channel (130) and the container outlet (110).
3. The apparatus (50) of claim 1, wherein,
The mixing channel (130) is defined by one or more mixing holes, and wherein the first cross-sectional area (a 1) is defined by the total cross-sectional area of the one or more mixing holes.
4. The device (50) according to any one of claims 1-3, wherein,
The first cross-sectional area (a 1) of the mixing channel is at least one of greater than 3mm 2 and less than 13mm 2.
5. The apparatus (50) of claim 4, wherein the first cross-sectional area (a 1) is at least one of greater than 4.5mm 2 and less than 9.1mm 2.
6. The apparatus (50) of claim 4, wherein,
The first cross-sectional area (a 1) of the mixing channel is at least one of greater than 5.1mm 2 and less than 7.1mm 2.
7. The device (50) according to any one of claims 1-3, wherein,
The second cross-sectional area (a 2) is a minimum cross-sectional area of a fluid passage of a mixture of the liquid medium and the pressurized gaseous medium from the mixing channel (130) to (i) the portion of the mixing pipe (120) downstream of the mixing channel (130) or (ii) the portion of the discharge line (140) downstream of the mixing pipe (120).
8. The device (50) according to any one of claims 1-3, wherein,
The second cross-sectional area (a 2) is at least one of greater than 28mm 2 and less than 133mm 2.
9. The device (50) according to any one of claims 1-3, wherein,
The mixing duct (120) has a third cross-sectional area (a 3) in the region of the mixing channel (130), wherein the ratio between the first cross-sectional area (a 1) and the third cross-sectional area (a 3) is greater than or equal to the ratio between the first cross-sectional area (a 1) and the second cross-sectional area (a 2).
10. The device (50) according to any one of claims 1-3, wherein,
The mixing duct (120) has a straight extension from a first end (122) located near the container outlet (110) to a second end (124) located near a container bottom (112) opposite the container outlet (110).
11. The device (50) according to any one of claims 1-3, wherein,
The volume of the mixing vessel (100) is between 3 liters and 500 liters.
12. The device (50) according to any one of claims 1-3, wherein,
The mixing vessel (100) is resistant to pressures up to between 3 bar and 15 bar.
13. The apparatus (50) of any one of claims 1-3, further comprising a nozzle (160) configured to discharge the gas-liquid mixture from the apparatus (50).
14. The apparatus (50) of any of claims 1-3, further comprising a control valve (150) configured to control the discharge of the gas-liquid mixture.
15. The apparatus of claim 14, wherein,
The control valve (150) is located between the discharge line (140) and the mixing conduit (120).
16. The device (50) according to any one of claims 1-3, further comprising:
a pressure tank (200), the pressure tank (200) being configured to store a pressurized gaseous medium; and
-A pressure line (210), the pressure line (210) extending from the pressure tank (200) to the mixing vessel (100).
17. The apparatus according to any one of claim 1 to 3, wherein,
At least 70% of the volume defined by the mixing vessel (100) is filled with the liquid medium, and wherein
The mixing channel (130) is located in a wall of the mixing conduit (120) such that the mixing channel (130) is located above a level of the liquid medium when at least 70% of a volume defined by the mixing vessel (100) is filled with the liquid medium.
18. A method of producing a gas-liquid mixture for fire fighting purposes with an apparatus (50) according to any one of claims 1 to 17, wherein a liquid medium is received in the mixing vessel (100) of the apparatus, the method comprising:
introducing a pressurized gaseous medium into the mixing vessel (100);
Introducing a pressurized gaseous medium into the liquid medium from outside the mixing conduit (120) via the mixing channel (130) comprised by the wall of the mixing conduit (120) when the liquid medium is directed within the mixing conduit (120) towards the vessel outlet (110); and
Directing the gas-liquid mixture toward the vessel outlet (110).
19. The method of claim 18, wherein the method further comprises:
-discharging the gas-liquid mixture from the apparatus (50) via a nozzle (160).
20. The method of claim 18 or 19, wherein:
The pressure within the mixing vessel (100) remains constant during actuation of the apparatus (50) to produce the gas-liquid mixture.
21. The method according to claim 18 or 19, wherein,
The mixing ratio of gaseous medium to liquid medium is between 30:1 and 70:1 parts by volume.
22. The method of claim 21, wherein the mixing ratio of gaseous medium to liquid medium is between 40:1 and 60:1 parts by volume.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP20162046.5 | 2020-03-10 | ||
| EP20162046.5A EP3878524A1 (en) | 2020-03-10 | 2020-03-10 | Device for producing a gas-liquid mixture for firefighting purposes |
| PCT/EP2021/056017 WO2021180773A1 (en) | 2020-03-10 | 2021-03-10 | Device for producing a gas-liquid mixture for firefighting purposes |
Publications (2)
| Publication Number | Publication Date |
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| CN115427115A CN115427115A (en) | 2022-12-02 |
| CN115427115B true CN115427115B (en) | 2024-07-05 |
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| CN202180028587.5A Active CN115427115B (en) | 2020-03-10 | 2021-03-10 | Device for producing a gas-liquid mixture for fire-fighting purposes |
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| Country | Link |
|---|---|
| EP (1) | EP3878524A1 (en) |
| CN (1) | CN115427115B (en) |
| WO (1) | WO2021180773A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998009683A1 (en) * | 1996-09-05 | 1998-03-12 | Sundholm Goeran | Installation for fighting fire |
| CN1200045A (en) * | 1996-09-05 | 1998-11-25 | 戈兰·桑德霍姆 | Installation for fighting fire |
| WO2016086321A1 (en) * | 2014-12-05 | 2016-06-09 | Jp Sicherheitstechnik Gmbh | Arrangement for producing an extinguishing-agent foam or active-substance foam |
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| GB734853A (en) * | 1951-09-05 | 1955-08-10 | Minimax Ag | Air foam fire extinguisher with foam improving device |
| RU2112572C1 (en) * | 1997-02-12 | 1998-06-10 | Душкин Андрей Леонидович | Pulverized liquid fire-extinguishing module |
| DE10109922A1 (en) | 2000-10-10 | 2002-05-08 | Anton Neumeir | Portable or rollable foam extinguisher with compressed gas foam consolidation |
| FR2888124B1 (en) * | 2005-07-07 | 2007-10-26 | Eurofeu Soc Par Actions Simpli | LIQUID FOG EXTINGUISHER AND USE THEREOF |
| CN201799038U (en) * | 2010-09-03 | 2011-04-20 | 中国石油化工股份有限公司 | Positive-pressure foam fire extinguisher |
| CN203620129U (en) * | 2013-11-22 | 2014-06-04 | 大连保税区荣昌消防设备工程有限公司 | Gas-storage foam fire extinguishing spray gun |
| DE202014010053U1 (en) * | 2014-12-05 | 2015-04-01 | Jp Sicherheitstechnik Gmbh | Arrangement for producing an extinguishing agent or active agent foam |
| KR101571003B1 (en) * | 2015-02-23 | 2015-11-23 | 주식회사 엠티케이방재시스템 | Compressed air foam extinguisher |
| CN205287325U (en) * | 2016-01-04 | 2016-06-08 | 福建水力消防成套设备有限公司 | Portable foam extinguishing device's improved generation structure |
| CN207384656U (en) * | 2017-09-12 | 2018-05-22 | 武汉迪克坦科技有限公司 | One kind is based on the pouring-in non-premixed type compressed air foam fire-extinguishing apparatus of positive pressure |
-
2020
- 2020-03-10 EP EP20162046.5A patent/EP3878524A1/en active Pending
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2021
- 2021-03-10 CN CN202180028587.5A patent/CN115427115B/en active Active
- 2021-03-10 WO PCT/EP2021/056017 patent/WO2021180773A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998009683A1 (en) * | 1996-09-05 | 1998-03-12 | Sundholm Goeran | Installation for fighting fire |
| CN1200045A (en) * | 1996-09-05 | 1998-11-25 | 戈兰·桑德霍姆 | Installation for fighting fire |
| WO2016086321A1 (en) * | 2014-12-05 | 2016-06-09 | Jp Sicherheitstechnik Gmbh | Arrangement for producing an extinguishing-agent foam or active-substance foam |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2021180773A1 (en) | 2021-09-16 |
| EP3878524A1 (en) | 2021-09-15 |
| CN115427115A (en) | 2022-12-02 |
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