WO2007001212A2

WO2007001212A2 - Mixer and fire-extinguishing apparatus

Info

Publication number: WO2007001212A2
Application number: PCT/RU2006/000331
Authority: WO
Inventors: Valeriy Nikolaevich Bordakov; Andrey Leonidovich Dushkin; Alexander Vladimirovich Karpyshev; Nikolai Nikolaevich Ryazanczev
Original assignee: Valeriy Nikolaevich Bordakov; Andrey Leonidovich Dushkin; Karpyshev Alexander Vladimirov; Nikolai Nikolaevich Ryazanczev
Priority date: 2005-06-29
Filing date: 2006-06-26
Publication date: 2007-01-04
Also published as: WO2007001212A3; RU2304993C2

Abstract

A mixer comprises a hermetically sealed casing (1) with a cavity to be filled with a liquid, and an ejector (4) located within the casing (1). The ejector (4) includes a flow-through channel (6) serving as a mixing chamber for liquids, an inlet part (5) with at least one ejection aperture (14) which communicates the flow-through channel (6) with the cavity of the casing (1), and an outlet part (7) equipped with at least one aperture (15) for communicating the cavity of the mixing chamber with the cavity of the casing. A fire-extinguishing apparatus comprises a water supply system equipped with a mixer whose cavity is to be filled with a foaming agent. The invention allows the efficiency of mixing the liquids to be increased at different spatial positions of the mixer and at variations in the liquid pressure and flow velocities.

Description

MIXER AND FIRE-EXTINGUISHING APPARATUS

Field of the invention

The invention relates to the units adapted for mixing liquids, which may be used as part of various kinds of equipment, particularly, in fire-extinguishing apparatuses. The invention may be implemented in various production processes wherein continuous mixing of different liquid components is carried out in predetermined weight or volume ratios.

Background of the invention Various types of mixers are presently known, which are utilized for mixing liquid components. For example, it is known from the description to Patent JP 11028478 (IPC C02F 1/68, published 02.02.1999) a mixer for liquids, said mixer being intended for mineralization of water carried out by providing flow circulation in a closed reservoir. A tank filled with a liquid solution of medicinal means is extending axially of the reservoir. Liquid circulation orifices are provided in the upper and lower parts of this tank. An axial pipe located within the tank is adapted for feeding air delivered by a compressor.

The apparatus operates in the following manner. The air is fed from the compressor through the axial pipe into the tank filled with a liquid solution of medicinal means. The liquid entrained from the tank by the air escaping from the pipe is then forced out via the upper orifices formed in the tank into the cavity of the reservoir. The forced out liquid in its turn ejects water from the reservoir through the lower orifices of the tank to draw the water into a circular motion. The water circulates until it is mineralized or homogeneously mixed to the desired extents.

However, during operation of the prior art apparatus an extended period of time is needed in order to achieve the desired extent of mixing the components with the result that additional electric power consumption is needed for air pumping.

It is known from the description to the Patent RU 2146556 (IPC BOlJ 19/24, published 20.03.2000) a mixer comprising a casing, a transverse partition wall with an inlet orifice, and a mixing chamber formed as a coaxially located pipe with a blanked-off end portion. In the upper part of the pipe equipped with the blanked-off end portion there are provided apertures.

During operation of the apparatus the liquid and gas are fed to an inlet orifice formed through the transverse partition wall. On passage thereof through the orifice provided in the partition wall, a submerged gas-and-liquid stream is generated, wherein a gaseous phase is broken by turbulent liquid pulses. The mixed stream is delivered into the mixing chamber, wherein a velocity field is equalized due to braking of the stream, and the pressure is partly recovered. The stream is divided after passage through the perforated walls of the mixing chamber. The main part of the stream circulates through an annular gap defined between the casing and the mixing chamber toward the lower part of the mixing chamber, and the stream portion equal in volume to the total flow rate of the components to be fed is supplied into the space above the upper end of the mixing chamber and discharged from a reactor. An internal circulation contour is thereby formed. The recirculating stream becomes enriched in a gaseous phase to a maximum gas content, at which gas content the penetration of a share of gaseous phase into the through-flow stream is initiated, said share corresponding to the balance equilibrium. The prior art apparatus has high capacity, however it does not permit adjustment of the ratio of components to be mixed.

The closest prior art to the claimed mixer is an apparatus disclosed in the Author's certificate SU 253476 (IPC B62D, published 30.09.1969). The mixer is made in the form of a horizontal hermetically sealed casing filled with a liquid. An ejector located in an axially symmetrically position within the casing consists of an inlet part formed as a nozzle with apertures, a mixing chamber, and a diffuser with a circular orifice for creating a circulating stream of the liquids to be mixed. The inlet part of the ejector is located in an axially symmetrically position within a conical socket equipped with openings. The mixing chamber is formed as a flow-through channel disposed within the cavity of the mixer casing. The prior art embodiment is aimed at improving the heat-exchanging process between the liquids to be mixed. The hermetically sealed casing of the mixer is filled with a liquid, and the main stream of the liquid to be mixed is fed through a pipe connection into the ejector nozzle to eject the liquid through the conical socket openings for filling the casing, and is mixed therewith within the mixing chamber of the ejector. One portion of the mixed stream is then recirculates into the casing through a slot-shaped aperture of the diffuser while other portion of the stream is fed through a discharge branch pipe to a take-up apparatus.

The prior art apparatus is formed large-sized in order to provide formation of a gas cavity above the surface of liquid which fills the hermetically sealed casing. Because of this, said apparatus may not be employed when the casing is arranged in a vertical position. Also known are fire-extinguishing apparatuses fitted with ejector-type mixers. For example, an apparatus described in the Author's certificate SU 1683784 Al (IPC A 62 C 35/00, published 15.10.1991) may be referred to such apparatuses. The known prior art fire-extinguishing apparatus comprises a water main, a pressure source for imparting flow velocity to the liquid, an ejector-type mixer, a fire hose, a device furnished with a head for applying a fire-extinguishing composition onto the surface of the fire site.

During operation of the apparatus, the liquid is fed under pressure into the ejector-type mixer. This causes creation in the mixer casing of a reduced pressure forcing the air into the mixing chamber, where it is mixed with the liquid. The resulted gas-and-liquid mixture is fed through a conduit and the fire hose into a liquid feeding device and is further discharged in the form of an atomized spray through the head to the outside and applied onto the fire site.

The prior art apparatus is formed large-sized and heavy-weight and has an increased power consumption. It is known from the description to the Author's certificate SU 183798 (IPC

B61C 17/00, published 01.01.1966) an apparatus including a reservoir containing a complete foaming mixture, a mixer, an air duct, hoses, valves, and reducers.

On opening of a valve, the air is delivered from the air duct through the reducers into a tank with the foaming mixture and further into the mixer. The foaming mixture is forced out by the air pressure from the tank via pipes into the mixer. On opening of the mixer valve, the foaming mixture and the pressurized air are simultaneously drawn into the mixer. The mixture is broken by means of a mesh located in the mixer and also by the pressurized air. This results in the generation of a high-expansion foam at the outlet end of the mixer socket, said foam being applied to the ignition site. The apparatus is of a complicated design and is made large-sized which is due to the utilization of the tank containing a preliminarily prepared aqueous solution of a foaming agent. Moreover, during operation of the apparatus large amounts of electric power are consumed due to the need for preliminary preparing of the aqueous solution of the foaming agent.

The closest prior art to the claimed fire-extinguishing apparatus furnished with a mixer is an apparatus disclosed in the description to the Author's certificate SU 286503 (IPC A62C 5/16, published 10.11.1970). The prior art fire-extinguishing apparatus comprises a water supply system (water main), a pressure regulator, a tank containing a foaming agent, a discharge conduit, a fire gun for feeding a foam-like stream, and an ejector-type mixer intended for mixing the foaming agent with water. The ejector-type mixer includes an inlet part and a flow-through channel serving as a chamber for mixing water with the foaming agent.

The water is fed from the external reservoir by means of a pump through the conduit into the ejector nozzle. At the instant a maximum amount of water flows through the pressure regulator mounted on the water main, the flow-through section in a suction branch pipe of the ejector-type mixer is immediately opened. The foaming agent is ejected to be further mixed with the main water flow within the mixing chamber of the ejector and delivered to the pump inlet. The aqueous solution of the foaming agent is fed by means of the pump into the fire gun to be further applied to the ignition site. The prior art apparatus is also of a complicated design which is connected with the presence of the tank with the foaming agent, regulators, a dosing device, and the pump. Also, the pump of the apparatus consumes rather large amounts of power for pumping of the liquid through a branched pipe system.

Disclosure of the invention

It is an objective of the claimed invention to create a compact apparatus simple in maintenance and allowing mixing of liquid components to be carried out not only in a horizontal but also in a vertical position, and also providing putting of a mixer into operating mode for reduced period of time. Another objective of the invention is to stabilize the ratio of the flow velocities of a foaming agent and a main stream (ejection coefficient) at various volumetric flow velocities of the components to be mixed. The mixer is supposed to operate in a wide range of pressures for feeding the main stream. Such a task is conditioned by the fact that upon connection of the mixer to a water supply system a substantial pressure deviation ranging between 3 and 10 bar is observed depending on the height of a building and the intensity of water consumption from a water-supply pipeline network. The solution of the above-mentioned problems allows the mixer to be effectively utilized in fire-fighting equipment.

The achievable technical result includes an increase in the operating efficiency of a mixer when the cavity of the casing is completely filled without forming an air space therein. In that instance the mixer can operate in different spatial positions: in a horizontal position as well as in a vertical position. The achievable technical result also includes a reduction in a period of time during which the mixer is put into an operating mode, and provision for a desired ratio of flow velocities of a foaming agent and a main stream regardless of a flow velocity and pressure of an external circulation flow. With regard to a fire-extinguishing apparatus, the achievable technical result includes an increase in the fire-extinguishing efficiency due to a reduced period of time for putting it into operating mode, and maintaining the flow velocity of the mixture of foaming agent at a desired level during the entire fire-extinguishing process. The invention is also aimed at reducing the weight and sizes of the fire-extinguishing apparatus, as well as at providing a suitable positioning of the apparatus in dwelling and commercial rooms under restricted space conditions.

The above technical results are provided by utilizing a mixer including a hermetically sealed casing whose cavity is to be filled with a liquid, and an ejector located within the hermetically sealed casing. The ejector includes a flow-through channel serving as a liquid mixing chamber, an inlet part with at least one ejection aperture which communicates the flow-through channel with the cavity of the casing, and an outlet part equipped with at least one aperture for communicating the flow-through channel with the cavity of the casing.

According to the present invention, a cross-sectional area SE of the aperture or apertures provided through the ejector outlet part is chosen on the condition:

S_E = (θ,01 ÷ 0,l)S_CH , where S_CH is a minimum cross-sectional area of the flow-through channel of the ejector.

In the case when a number of equally sized apertures are formed through the outlet part of the ejector, the cross-sectional area SE of the equally sized apertures formed through the outlet part of the ejector is defined from the ratio: S_E ⁼nS_» where n is a number of apertures, Sj is a cross-sectional area of each of the apertures provided through the outlet part of the ejector.

The invention is based on the following physical principles. The ejection of an additional component such as a foaming agent into the main stream of the liquid flowing via the flow-through channel results in the creation of a reduced pressure in the cavity of the hermetically sealed casing. It is obvious that after a lapse of a certain period of time the ejector will be set to a maximum operating mode with regard to the residual pressure value. The pressure of the additional liquid component in the cavity of the mixer casing will decrease to a predetermined level and, thereafter, the ejection of the liquid component into the main stream will be ceased. In order to provide for a continuous operating mode of the mixer, a reduced pressure tending to occur in the chamber containing the additional liquid component should be continuously compensated. To this end, at least one side aperture is formed in the outlet part of the ejector, said side aperture having a sufficiently small cross-sectional area. A portion of the mixed stream is delivered from the flow-through channel of the ejector through the given aperture into the cavity of the mixer casing. The cross-sectional area of such an aperture or apertures is chosen so as to ensure maintaining a predetermined flow velocity of the liquid to thereby provide a complete compensation of the pressure drop within the cavity of the hermetically sealed casing of the mixer. By changing the diameter of the side apertures serving for recirculation of the mixed stream, the ratio of volumetric flow velocities of the liquid components under the mixing process may be varied. The apertures formed through the outlet part of the ejector are advantageously formed equal in diameter. The range of cross-sectional areas of the apertures provided through the outlet part of the ejector is chosen depending on the cross-sectional area of the flow-through channel of the ejector. Fulfillment of the established dependence between the cross-sectional area of the apertures provided through the outlet part of the ejector and the cross-sectional area of the flow-through channel ensures a stable ratio of flow velocities of the main stream and the ejected liquid stream and mixing thereof regardless of variations in the flow velocities and the delivery pressure of the main stream.

The minimum value of the given range is conditioned by the fact that with the cross- sectional area S_E < 0,015c_# of the aperture, the hydraulic resistance of the passage, via which the flow-through channel of the ejector is communicating with the cavity of the mixer casing and wherein the liquid stream recirculates, is substantially high. This will essentially hinder the recirculation of liquid through such an aperture. As a consequence, the pressure drop within the mixer casing will be compensated rather slowly.

As for the upper limit to the range of the cross-sectional area SE ≤ 0,1 S_CH of the aperture, the given condition defines the possibility of dosed feeding of the additional liquid component into the main liquid stream supplied under pressure via the flow-through channel of the ejector and also the feasibility of regulating the ratio of components to be mixed through changing the sizes of the apertures.

For the purpose of effective utilization of the entire volume of the ejector where the liquid components are to be mixed, each of the apertures formed through the outlet part of the ejector is provided at a distance of from 1 to 10 mm from the internal surface of the adjacent end part of the mixer casing.

In order to ensure a desired intensity and homogeneity of mixing the components, the internal diameter dc_H of the flow-through channel is chosen on the condition: d_CH = (l .5 ÷2.6)d₀ , where d₀ is an internal diameter of the passage of the inlet part of the ejector. The inlet part of the passage of the inlet part of the ejector is formed as an axial cylindrical passageway. Choosing the diameter of the flow-through channel from the indicated range of diameters provides not only ejection of the additional liquid component stream from the cavity of the casing, but also high-intensity mixing of the liquid components. In case the internal diameter of the flow-through channel exceeds 2.6d₀, the difference in the flow velocities of the main stream and the ejected stream at the leading portion of the flow-through channel will be increased with the result that the mixing homogeneity may be deteriorated due to the essential differences in the distribution of flow velocities across section of the flow-through channel (mixing chamber). On the other hand, a reduction in the diameter of the flow-through channel to the value less than 1.5d₀ results in a decrease in the intensity and homogeneity of mixing the liquid components.

The inlet part of the mixer ejector may be formed as a circular nozzle converging in the course of flow of the liquid via the flow-through channel, said circular nozzle being equipped with a coaxial axial cylindrical passageway provided through the internal part thereof, with the ejection apertures for communicating the flow-through channel with the cavity of the casing being provided through the external part of the circular nozzle.

In the preferred version of embodiment of the mixer, four equally sized ejection apertures are provided through the external part of the circular nozzle, said ejection apertures being arranged symmetrically about an axis of symmetry of the axial cylindrical passage.

The equally sized ejection apertures may be differently configured, for example of round or rectangular cross-section. The shape and number of ejection apertures are defined in accordance with the desired ejection (dosing) coefficient and depend upon the process used for manufacturing the ejector. The experiments performed have shown that in order to ensure an effective ejection of an additional liquid component and to create a circular flow with a constantly maintained component ratio regardless of the flow velocity and pressure of the main stream it is advisable that the area Sc of the equally sized ejection apertures provided through the external part of the circular nozzle be chosen on the condition: S_c = kS_Cl = {l÷3)S_Q, where k is a number of ejection apertures, Sci is a cross-sectional area of each of the ejection apertures, S₀ is a cross- sectional area of the flow-through passage of the ejector inlet part.

If the cross-sectional area Sc of the ejection apertures is smaller than the cross-sectional area So of the inlet part of the ejector flow-through channel, it will result in a decreased ejection coefficient and, accordingly, an increased flow velocity of the main liquid component in comparison with a predetermined flow velocity.

It should be also pointed out that in case the mixer is used as part of the fire-extinguishing apparatus, when the area Sc of the ejection apertures deviates from a predetermined ratio, an uncontrolled reduction in the expansion degree of the foam generated during mixing of water with a foaming agent will occur. On the other hand, if the area Sc of the ejection apertures exceeds 3 S₀, the flow velocity of the foaming agent will be essentially increased.

In a preferred version of embodiment, the circular nozzle passage is defined by conical surfaces, with an inclination angle of the conical surface generatrices relative to an axis of symmetry of the flow-through channel being chosen within the range of from 5° to 20°.

The above technical results are also reached with the use of a fire-extinguishing apparatus comprising a water supply system, a discharge conduit connected to a fire gun intended for applying of a foam-like stream onto an ignition site, a tank to be filled with a foaming agent, and a mixer comprising an ejector. The ejector includes as part an inlet part, a flow-through channel serving as a mixing chamber for water and a foaming agent, and an outlet part.

According to the present invention, the mixer is equipped with a hermetically sealed casing whose cavity defines a volume to be filled with a foaming agent. The ejector is mounted within the hermetically sealed casing. The inlet part of the ejector is provided with at least one ejection aperture which communicates the flow-through channel with the cavity of the casing. The outlet part of the ejector is provided with at least one aperture for communicating the flow-through channel with the cavity of the casing. The cross-sectional area SE of the aperture or apertures provided through the outlet part of the ejector is chosen on the condition: S_E = (θ,Ol ÷O,l)S_CH , where S_CH is a minimum cross-sectional area of the flow- through channel of the ejector. The invention allows both horizontal and vertical arrangement of the mixer casing because there is practically no gas cavity in the hermetically sealed casing of the mixer during operation thereof. The pressure drop in the mixer casing is compensated automatically by recirculation of the components under mixing process.

Owing to the automatic pressure regulation in the hermetically sealed casing of the mixer, the claimed fire-extinguishing apparatus may be connected to any of the liquid supply systems, including a stationary water main wherein liquid pressure and flow rate fluctuations are probable.

In case the outlet part of the ejector is provided with a number of equally sized apertures, the cross-sectional area S_E of the apertures is determined from the condition: S_E =«£/, where n is a number of apertures, Sj is a cross-sectional area of each of the apertures formed through the outlet part of the ejector. The following additions are possible in various versions of embodiment of the fire- extinguishing apparatus: each of the apertures formed through the outlet part of the ejector is provided at a distance of from 1 to 10 mm from the internal surface of an adjacent end part of the casing; - the internal diameter dc_H of the flow-through channel is chosen on the condition: d_CH = (l.5 ÷2.6)d_Q , where d₀ is an internal diameter of the passage in the inlet part of the ejector; the inlet part of the mixer ejector is made in the form of a circular nozzle converging in the course of flow of the liquid via the flow-through channel, said nozzle being provided with a coaxial axial cylindrical passageway formed through the internal part thereof, while the ejection apertures for communicating the flow-through channel with the casing cavity are provided through the external part of the circular nozzle; four equally sized ejection apertures are formed through the external part of the circular nozzle, said ejection apertures being arranged symmetrically about an axis of symmetry of the circular nozzle, at that the ejection apertures may have circular or rectangular cross section; the area Sc of the ejection apertures provided through the external part of the circular nozzle is chosen on the condition: S_c = kS_a = (l÷3)S₀, where k a number of ejection apertures, Sci is a cross sectional area of each of the ejection apertures, S₀ is a cross sectional area of the flow-through passage of the ejector inlet part; - the circular nozzle passage may be defined by conical surfaces, with an inclination angle of the conical surface generatrices relative to an axis of symmetry of the mixer being preferably chosen within the range of from 5° to 20°; the water supply system may include as parts a filter, a back valve, and an inlet valve, said parts being arranged in series, said inlet valve being connected to the mixer inlet, and the discharge conduit being connected to the fire gun through a cutoff device; the fire gun of the fire-extinguishing apparatus may be furnished with a spray atomizer; the cutoff device of the water supply system may be formed as a valve, a back valve or a destructible membrane.

Brief description of drawings

The invention is further explained by the examples of specific embodiments with references to the exemplifying drawings. A mixer designed for generation of a fire- extinguishing composition, wherein a foaming agent is added to a main water stream, is considered as an example of embodiment of the invention. The exemplifying drawings illustrate the following: Fig. 1 is a longitudinal section of a mixer taken in a 1 :2 scale; Fig. 2 is a schematic diagram of a fire-extinguishing apparatus; Fig. 3 is a view of a fire-extinguishing apparatus taken in a 1 :4 scale.

Preferable example of embodiment of the invention

A mixer illustrated in Fig. 1 structurally represents on the whole a liquid-to-liquid ejector wherein a stream of main liquid, particularly water, ejects a foaming agent from a conduit by the action of a hydrodynamic effect. The design of the mixer is illustrated in Fig. 1. The mixer is adapted for generation of a fire-extinguishing mixture of water and a foaming agent.

The mixer comprises a hermetically sealed casing 1, inlet and outlet connection pipes 2 and 3, respectively. An ejector 4 is mounted within the casing. The ejector 4 includes as part an inlet part 5, a flow-through channel 6 serving as a mixing chamber, and an outlet part 7. The inlet connection pipe 2 is used for connecting the mixer to a delivery water pipeline and feeding the water to the ejector 4. The outlet connection pipe 3 is used for feeding a fire- extinguishing composition generated within the flow-through channel 6 of the ejector 4 into a discharge conduit coupled through a valve to a fire hose.

The casing 1 is hermetically closed at its ends with flat covers 8 and 9, wherein the inlet connection pipe 2 and the outlet connection pipe 3 are set in axially symmetrical relationship, respectively. A connection pipe 10 with a hermetically sealing plug fitting 11 is mounted on the cover 9 for filling the cavity of the casing 1 with a foaming agent. The inlet part 5 of the ejector is formed as a circular nozzle 12 converging in the course of flow of the liquid via the flow-through channel. The passage of the circular nozzle 12 is defined by conical surfaces.

A coaxial axial cylindrical passageway 13 is formed within the internal part of the circular nozzle 12. Ejection apertures 14 formed in the external part of the circular nozzle 12 are used for creating an ejection zone in the main liquid stream. The flow-through channel 6 of the ejector functions as a mixing chamber and is adapted for producing a mixture of water and a foaming agent.

In the example under consideration, the outlet part 7 of the ejector is formed as a diffuser whose outlet part is connected in sealing relationship with the outlet connection pipe 3. An aperture 15 is provided through the outlet part 7 of the ejector, said aperture being spaced by a distance of 6 mm from the internal surface of the adjacent end part of the casing 1 (the surface of the cover 9) and serving for compensating the reduced pressure created in the casing 1 after ejection of the foaming agent into the main water stream. The diameter d_ex of the aperture 15 is chosen in accordance with an essential condition of the invention: S_E = (O.Ol÷ O.l)-?^ and is equal to 1.5 mm. The cross-sectional area S_E of the

aperture 15 is mm 2. The minimum cross sectional area S_E of the flow-

through channel 6 of the ejector is 113 mm 2. In the example of embodiment of the mixer under consideration (see Fig. 1) four ejection apertures 14 of rectangular section are provided in the external part of the circular nozzle. The total cross-sectional area Sc of the ejection apertures 14 is 132 mm² to comply with the condition: S_c = kS_Q = (l ÷ 3)S₀ , where k=4 is a number of ejection apertures; Sci=33 mm² is a cross-sectional area of each of the ejection apertures 14;

?2

S₀ = — = 50 mm² is a cross-sectional area of a discharge opening of an ejector nozzle;

d_o=8 mm is an internal diameter of the flow-through passage of the ejector inlet part (a diameter of the axial cylindrical passageway 13).

In the example under consideration, the inclination angle α of the generatrices of the conical surfaces defining the circular passage relative to the axis of symmetry of the flow- thorough channel (see Fig. 1) makes 17° to comply with the chosen range of from 5° to 20°.

The internal diameter dcπ of the flow-through channel 6 of the ejector is chosen in compliance with the condition: d_CH = (l .5 ÷ 2.6)d₀ , and makes 12 mm.

The internal volume of the casing 1 of the mixer 20 (see Fig.2) is chosen depending on the desired service time for the fire-extinguishing apparatus operating in the mode of mixing water with a predetermined amount of the foaming agent (generally 40-60 s for extinguishing ignition sites in the rooms).

The fire-extinguishing apparatus whose schematic diagram is illustrated in Fig. 2 comprises as parts a water supply system including a filter 16 connected to a water main section 17, a back valve 18, and an inlet valve 19 connected to the inlet of the mixer 20, said parts of said water supply system being arranged in series.

A discharge conduit of the mixer 20 is coupled to a fire gun 21 designed for applying a foam-like stream onto an ignition site through a cutoff device, with a valve 22 being used as a cutoff device in the example under consideration. The fire gun 21 is provided with an atomizer 23 for effective spraying of the foam-like stream over a maximum area of the ignition site. In the example under consideration the fire gun 21 with the atomizer 23 are structurally integrated to a controllable hydraulic valve providing for an adjustable feeding of the foam- like fire-extinguishing stream. The given integral structural unit is communicated with an outlet of the valve 22 through a flexible fire hose 24. In specific examples of embodiment of the invention, a back valve or a destructible membrane may be used as a cutoff device.

The fire-extinguishing apparatus illustrated in Fig. 3 provides for a directional applying of a foam-like fire-extinguishing stream preliminarily generated in the mixer 20 through the fire gun 21 with the atomizer 23. The controllable hydraulic valve includes a lever 25 which is used by an operator for regulated applying of the fire-extinguishing composition onto the ignition site.

The integral structural unit including the hydraulic valve and the fire gun 21 with the spray atomizer is connected to the flexible fire hose 24 by means of collars 26. The hose 24 is connected at its opposite side to the cutoff valve 22 by means of collars 27. The valve 22 is communicating through a conduit section 28 to the outlet of the mixer 20 whose inlet is connected to the water main section 17.

The fire-extinguishing apparatus and the mixer as part thereof operate as follows. The internal volume of the casing 1 of the mixer 20 is preliminarily filled with a foaming agent through the connection pipe 10. After the cavity of the casing 1 is completely filled with the foaming agent, the connection pipe 10 is closed by means of the hermetically sealing plug fitting 11. In the given example of embodiment of the invention, the mixer is set in a horizontal position according to the apparatus mounting conditions.

Upon occurrence of an ignition site, the valves open a tap (not shown in the drawing) mounted on the water main. The inlet valve 19 and the valve 22 are then moved to an open position. The water is thereafter delivered into the section 17 of the water main. The tap water is passed through the filter 16 to be cleaned from solid contaminants. The back valve 18 prevents penetration of the foaming agent into the water main. The water free from solid contaminants is then fed through the opened inlet valve 19 into the inlet connection pipe 2 to flow further into the flow-through channel 6 of the ejector via the axial cylindrical passageway 13 of the circular nozzle 12.

As a result of the ejection effect produced during flowing of the liquid stream through the converging circular nozzle, the foaming agent is fed in dosed portions from the cavity of the casing 1 through the ejection apertures 14 and the circular passage defined by the external and internal parts of the circular nozzle 12. The flow velocity of the foaming agent depends not only on the size of the ejection apertures 14, but also on the pressure within the cavity _.of the casing 1. The foaming agent is uniformly ejected circumferentially of the cross section of the main liquid stream due to the utilization of the ejection apertures having equal section, said apertures being arranged in equally spaced relation circumferentially of the external part of the circular nozzle 12.

The ejected stream of the foaming agent is delivered in conjunction with the main water stream into the flow-through channel 6 of the ejector 4, wherein the liquid components are intensively mixed. In the given apparatus, the flow-through channel 6 functions as a mixing chamber. The efficiency of mixing the components depends on the ratio of sectional sizes of the flow-through channel 6 of the ejector 4 to the axial cylindrical passageway 13 of the circular nozzle 12.

The maximum effective mixing of the liquid components is observed when the following condition is fulfilled: d_CH = (l.5 ÷2.6)<i₀ , where dcH is an internal diameter of the flow- through channel of the ejector; do is an internal diameter of the passage of the ejector inlet part (diameter of the axial cylindrical passageway 13).

Ejection of the foaming agent from the casing 1 into the flow-through channel 6 results in the creation of a reduced pressure within the cavity of the casing 1. On flowing of water and the foaming agent via the flow-through channel 6, the foaming agent and water are mixed. Braking of the mixture within the outlet part of the ejector causes an increase in the pressure of stream within the outlet connection pipe 3. As a result, a portion of the mixed stream begins to flow through the aperture 15 provided through the outlet part 7 of the ejector into the internal volume of the casing 1 from which the foaming agent is taken out. Recirculation of the mixture through the aperture 15 formed through the outlet part of the ejector provides for a compensation of the reduced pressure within the internal volume of the casing 1. The pressure compensation is provided at a minimum flow velocity of the fire-extinguishing composition delivered through the aperture 15 into the cavity of the casing 1. As a result, the concentration of the foaming agent filling the cavity of the casing 1 is maintained at a desired level throughout the entire process of applying the foam-like fire extinguishing stream onto the ignition site. The dosed adding of the foaming agent into the main liquid stream carried out simultaneously with the automatic compensation of the reduced pressure within the cavity of the casing 1 is defined by a predetermined ratio between the cross-sectional area S_E of the aperture 15 and the cross sectional area SCH of the flow-through channel 6 of the ejector 4: S_£ = (0.01÷ 0.l)S ^J _cCH The foam-like fire-extinguishing composition mixed within the flow-through channel 6 of the ejector is delivered through the outlet connection pipe 3, which is joined by a conduit section 28 with the opened valve 22, into the flexible fire hose 24. The fire hose 24 is unwound up to the ignition site. Upon filling the entire volume of the fire hose 24, the operator directs the fire gun 21 to the ignition site and depresses the lever 25 of the hydraulic valve. Thereafter, the fire-extinguishing composition is fed through the fire gun 21 into the atomizer 23. An atomized foam- like stream of the fire-extinguishing composition generated at the outlet of the atomizer 23 is applied onto the ignition site.

Utilization of the claimed invention for extinguishing the ignition sites with the use of foam-like streams of fire-extinguishing composition allows the time for putting the apparatus into an operating mode for the generation of fire-extinguishing composition to be decreased and dosed adding of the foaming agent to the liquid stream to be provided upon variations in the liquid pressure and flow velocity values at the inlet end of the apparatus. As a consequence, the fire-extinguishing apparatus comprising the mixer allows the ignition sites to be effectively suppressed and localized before the fire-fighting service subdivision arrives.

Industrial application of the invention

The fire-extinguishing apparatus may be employed in fire-fighting equipment for suppressing the ignition sites on various objects, such as dwelling and office rooms, hospital, library and museum premises.

The claimed mixer may be employed in various processing apparatuses as an individual unit for continuous mixing of liquid components used in a predetermined ratio.

The above examples of embodiment of the invention are considered advantageous, however these examples do not exhaust any other possible versions of embodiment of the invention, provided that said versions are based on the claims of the invention, and may be implemented with the use of the means and technologies known to those skilled in the art.

Claims

1. A mixer comprising a hermetically sealed casing (1) with a cavity to be filled with a liquid, an ejector (4) located within the hermetically sealed casing (1) and including a flow- through channel (6) serving as a chamber for mixing the liquids, an inlet part (5) with at least one ejection aperture (14) which communicates the flow-through channel (6) with the cavity of the casing (1), and an outlet part (7) provided with at least one aperture (15), through which aperture the flow-through channel (6) is communicating with the cavity of the casing (1), is characterized in that the cross-sectional area S_E of the aperture or apertures (15) formed through the outlet part (7) of the ejector (4) is chosen on the condition: S_E = (θ.Ol÷O.l)5_CT , where S_CH is a minimum cross-sectional area of the flow-through channel (6) of the ejector

(4).

2. The mixer according to the claim 1 is characterized in that the cross-sectional area of the equally sized apertures (15) formed through the outlet part (7) of the ejector (4) is defined from the condition: Sβ-nSu where n is a number of apertures (15), Si is a cross-sectional area of each of the apertures (15) formed through the outlet part (7) of the ejector (4).

3. The mixer according to the claim 1 is characterized in that each of the apertures (15) formed through the outlet part (7) of the ejector (4) is provided at a distance of from 1 to 10 mm from the internal surface of the adjacent end part of the casing (1).

4. The mixer according to the claim 1 is characterized in that the internal diameter dc_H of the flow-through channel (6) of the ejector (4) is chosen on the condition: d_CH = (l.5 ÷2.6)d₀ , where d₀ is an internal diameter of the passage of the inlet part (5) of the ejector (4).

5. The mixer according to the claim 1 is characterized in that the inlet part (5) of the mixer ejector (4) is formed as a circular nozzle (12) converging in the course of flow of the liquid via the flow-through channel (6), said circular nozzle being provided with a coaxial axial cylindrical passageway (13) formed though the internal part of the circular nozzle (12), the ejection apertures (14) for communicating the flow-through channel (6) with the cavity of the casing (1) being provided through the external part of the circular nozzle (12).

6. The mixer according to the claim 5 is characterized in that four equally sized ejection apertures (14) are formed through the external part of the circular nozzle (12), said ejection apertures being arranged symmetrically about the axis of symmetry of the circular nozzle (12).

7. The mixer according to the claim 5 is characterized in that the cross-sectional area Sc of the equally sized ejection apertures (14) formed through the external part of the circular nozzle (12), is chosen on the condition: S_c = kS_a = (l÷3)iSO, where £ is a number of ejection apertures (14), Sci is a cross-sectional area of each of the ejection apertures (14), S₀ is a cross- sectional area of the flow-through passage provided through the inlet part (5) of the ejector (4).

8. The mixer according to the claim 5 is characterized in that the passage of the circular nozzle (12) is defined by conical surfaces, with an inclination angle of generatrices of the conical surfaces relative to the axis of symmetry of the flow-through channel (6) making from 5° to 20°.

9. A fire-extinguishing apparatus comprising a water supply system, a discharge conduit connected to a fire gun (21) adapted for applying a foam-like stream onto an ignition site, a tank to be filled with a foaming agent, and a mixer (20) comprising an ejector (4) including an inlet part (5), a flow-through channel (6) serving as a mixing chamber for water and a foaming agent, and an outlet part (7), is characterized in that the mixer (20) is provided with a hermetically sealed casing (1) whose internal cavity defines a tank to be filled with a foaming agent, the ejector (4) being located within the hermetically sealed casing (1), the inlet part (5) of the ejector (4) being provided with at least one ejection aperture (14) which communicates the flow-through channel (6) with the cavity of the casing (1), the outlet part (7) being provided with at least one aperture (15) for communicating the flow-through channel (6) with the cavity of the casing (1), and the cross-sectional area S_E of the aperture (15) or apertures (15) formed through the outlet part (7) of the ejector (4) being chosen on the condition: S_E = (θ.Ol ÷ O. l)S_CH , where S_CH is a minimum cross-sectional area of the flow-through channel (6) of the ejector (4).

10. The apparatus according to the claim 9 is characterized in that the cross-sectional area of the equally sized apertures (15) formed through the outlet part (7) of the ejector (4) is defined from the condition: S_E-ΠS_I, where n is a number of apertures (15), Sj is a cross- sectional area of each of the apertures (15) formed through the outlet part (7) of the ejector (4).

11. The apparatus according to the claim 9 is characterized in that each of the apertures provided through the outlet part (7) of the ejector (4) is located at a distance of 1 to 10 mm from the internal surface of the adjacent end part of the casing (1).

12. The apparatus according to the claim 9 is characterized in that the internal diameter dcH of the flow-through channel (6) of the ejector (4) is chosen on the condition: d_CH = (l.5 ÷2.6)d₀ , where do is an internal diameter of the passage of the inlet part (5) of the ejector (4).

13. The apparatus according to the claim 9 is characterized in that the inlet part (5) of the ejector (4) of the mixer (20) is formed as a circular nozzle (12) converging in the course of flow of the liquid via the flow-through channel (6), said circular nozzle being equipped with a coaxial axial cylindrical passageway (13) provided within the internal part of the circular nozzle (12), with the ejection apertures (14) for communicating the flow-through channel (6) with the cavity of the casing (1) being provided through the external part of the circular nozzle (12).

14. The apparatus according to the claim 13 is characterized in that four equally sized ejection apertures (14) are formed through the external part of the circular nozzle (12), said ejection apertures being arranged symmetrically about the axis of symmetry of the circular nozzle (12).

15. The apparatus according to the claim 13 is characterized in that the cross-sectional area Sc of the equally sized ejection apertures (14) provided through the external part of the circular nozzle (12) is chosen on the condition: S_c = kS_Cl = (l÷3)S₀, where A: is a number of the ejection apertures (14), Sa is a cross-sectional area of each of the ejection apertures (14), So is a cross-sectional area of the flow-through passage of the inlet part (5) of the ejector (4).

16. The apparatus according to the claim 13 is characterized in that the passage of the circular nozzle (12) is defined by conical surfaces, with an inclination angle of the conical surface generatrices relative to the axis of symmetry of said circular nozzle (12) constituting from 5° to 20°.

17. The apparatus according to the claim 9 is characterized in that the water supply system comprises as parts a filter (16), a back valve (18), and an inlet valve (19), said parts of said system being arranged in series, said inlet valve (19) being connected to an inlet of the mixer (20), and the discharge conduit being connected to the fire gun (21) through a cutoff device.

18. The apparatus according to the claim 17 is characterized in that said cutoff device is formed as a valve (22).

19. The apparatus according to the claim 17 is characterized in that said cutoff device is formed as a back valve.

20. The apparatus according to the claim 17 is characterized in that said cutoff device is formed as a destructible membrane.

21. The apparatus according to the claim 9 is characterized in that said fire gun (21) is equipped with an atomizer (23).