RU2247584C2 - Method for fire curtain creation and screen device - Google Patents

Abstract

FIELD: fire-protection equipment, particularly means for deflection and absorption of radiant fire energy.

SUBSTANCE: method involves moving fire protection curtain from any screen side with provision of specific cooling agent flow rate of 3-4 l/min per one screen meter. Screen is made of hygroscopic material. Device includes screen made as frame and web of hygroscopic material, namely gauze, pulled on frame. Installed above screen is nozzle mounted on pipeline with the use of flexible connection so that protective curtain may be fed as film flow from any screen side if necessary. Screen is placed perpendicular to heat flow. After establishing stable heat flow from emitter protective curtain in the form of film flow of cooling agent is fed from nozzle so that film flow passes over any screen side.

EFFECT: creation of continuous film flow having no gaps with low flow rates of cooling agent due to forming screen of hygroscopic material; creation of waves on curtain surface, which results in curving curtain surface and in increasing of infrared radiation deflection.

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Description

The invention relates to the field of fire fighting equipment and is intended to create shielding devices for the purpose of reflection and absorption of radiant energy arising from a fire.

Known methods for creating fire curtains using screens (M.Ya. Roitman, Fire regulation in construction. M., Stroyizdat, 1985, p.253-257), which consist of installing stationary or mobile screens in the protected volume. Screens without thermal resistance are used, reflecting only radiant energy, and heat-removing screens, which mainly absorb heat themselves or cool heated surfaces with a water curtain.

A known method of creating a fireproof translucent chain (mesh) curtains of wire, cooled by water. The protective effect of wire curtains made of metal wire lies in the fact that the grid localizes convective flows and, consequently, heat transfer by convection (M.Ya. Roitman, Fire regulation in construction, M., Stroyizdat, p.260).

To create water curtains, it is recommended to use sprinkler or deluge heads intended for fragmentation of the jet. Moreover, these heads are located at a distance of 2.5 m from the calculation of the flow rate of 0.5 l / s per 1 square. meter irrigated plane. The use of aerodispersed curtains is provided only after additional constructive study and extreme testing. Moreover, the operation of these devices depends to a greater extent on the quality of the water supplied to create the curtain (the same, p. 261).

However, based on the fact that the total water flow required to create a curtain reaches large values, the use of this method as part of other automatic fire extinguishing installations can create a problem of uninterrupted water supply with an existing water supply system at the facility (E.N. Ivanov, Fire protection of open installations. M., Chemistry, 1986, p. 83-95).

Known anti-smoke fire system, which provides for the creation of a fire non-flammable curtains, cutting off a certain part of the room from the place of fire. At the same time, the curtain is poured on both sides by jets of water discharged from fire hydrants (Japanese application No. 670991, class A 62 from 2/06 of 03/15/1994).

However, the use of fire hydrants leads to significant consumption of water used to cool the curtains and does not allow the formation of the most efficient continuous film flow for cooling.

A known method of creating a fire curtain, including the installation of a mesh screen and the supply of a protective cooling curtain to it from the side opposite to the direction of the heat flux (UK application No. 2266051, class A 62 C 2/00, publ. 20.10.1993).

However, in this case, a protective cooling curtain is supplied to the mesh screen in the form of a droplet flow, which leads to the dynamic interaction of the latter with the mesh coating. As a result, discontinuities in the resulting film flow occur and uneven filling of the mesh coating cells. In addition, the basic principle of creating this fire curtain is based on the formation of a vapor curtain, and not on the reflection of infrared radiation on the curved surface of the film, which, as was said earlier, as a result of filling mesh cells with the cooling agent.

The closest analogue adopted for the prototype of the proposed method and device is a method of creating a fire curtain, including installing a screen and supplying a protective curtain along it in the form of a film stream from a nozzle mounted above the screen (application of the Russian Federation No. 99114862, class A 62 C 2 / 08, published September 27, 2000, Bull. No. 27).

This invention improves the efficiency of the shielding device at low flow rates of the cooling agent.

To this end, in a method of creating a fire curtain, including installing a screen and supplying a protective curtain along it in the form of a film stream from a nozzle mounted above the screen, a protective curtain is fed from either side of the screen with a specific coolant flow rate of 3 to 4 l / min per meter the latter, and in a shielding device containing a screen made in the form of a frame on which a web is stretched, and means for supplying a cooling agent to the screen, the web is made of hygroscopic material, for example, gauze.

An advantage of the claimed invention is the use of wave flows of thin layers of viscous liquid, which occur when a cooling agent is supplied from either side of the screen with a specific flow rate of 3 to 4 l / min per linear meter of the latter (for water - 25? Re?? 75).

The boundary of wave formation (Re _w ) is determined by the formula of P.L. , 1948):

where Fi is the Kapitza number,

where Fi = σ ³ / gy ⁴ ρ ³ ,

where σ is the coefficient of surface tension of the liquid;

ν is the kinematic viscosity of the liquid:

ρ is the fluid density;

g is the acceleration of gravity.

The manufacture of a web of hygroscopic material, for example, gauze, allows one to obtain a continuous film flow without discontinuities at low cooling agent costs, and the creation of surface waves leads to an additional curvature of the surface of the film flow and, accordingly, to a more intense reflection of infrared radiation. Moreover, as the tests showed, the temperature of the film stream at the inlet from the screen did not rise above 60 ° C.

In the case of the manufacture of a fabric of practically non-hygroscopic material, for example in the form of a metal mesh (application of the Russian Federation No. 99114862, class A 62 C 2/08, publ. 09/27/2000. Bull. No. 27), leads to the formation of discontinuities in the film flow the above costs of the cooling agent, and the formation of surface waves in this case is not observed.

The drawing shows a General view of a shielding device that implements the inventive method.

The device 1 consists of a shielding device 2, made in the form of a frame, on which a web made of hygroscopic material, such as gauze, is stretched. The nozzles 3 mounted on the pipeline 4 are mounted above the shielding device. Moreover, the nozzles 3 are mounted on the pipeline 4 by means of a flexible connection so that, if necessary, the protective curtain is supplied in the form of a film stream 7 from either side along the screen with a specific flow rate of cooling agent from 3 to 4 l / min per linear meter of the latter. The shielding device 2 itself was placed perpendicular to the heat flux. To measure heat fluxes, special heat radiation sensors 5 and 6 were installed. Sensor 5 was mounted in front of the shielding device 2, covered with a film stream 7 of the cooling agent, and sensor 6 was installed behind the specified shielding device. In both cases, the heat radiation sensors 5 and 6 were located before the film stream 7 of the cooling agent, which was supplied from one side of the shielding device 2. The electrical signal from the sensors 5 and 6 was output to the processing unit 8.

The device operates as follows.

After establishing a stable heat flux emanating from the emitter, a protective curtain is supplied from the nozzle 3 in the form of a film stream 7 of a cooling agent, which washes along the screen of the shielding device 2 from either side. The specific consumption of the cooling agent ranged from 3 to 4 l / min per linear meter of the shielding device. Moreover, the manufacture of the screening device web 2 from a hygroscopic material, such as gauze, allows one to obtain a continuous film flow without discontinuities at low, as previously indicated, coolant costs, and the creation of surface waves leads to an additional curvature of the surface of the film stream and, accordingly, to more intense reflection of infrared radiation.

Sensors 5 and 6 recorded the intensity of the corresponding heat fluxes.

The efficiency of the device was evaluated by the degree of attenuation of the heat flux. The attenuation coefficient of the heat flux was determined by the formula:

K = I ₀ / I ₁ ,

where I ₀ - the intensity of the heat flux to the shielding device, kW / m ² ;

I ₁ - the intensity of the heat flux after the shielding device, kW / m ² .

The installation is reliable in operation and convenient in operation.

Claims (2)

1. A method of creating a fire curtain, including installing a screen and supplying a protective curtain along it in the form of a film stream from a nozzle mounted above the screen, characterized in that the protective curtain is supplied from either side of the screen with a specific coolant flow rate of 3 to 4 l / min per linear meter of the latter. 2. A shielding device comprising a screen made in the form of a frame on which the web is stretched, and means for supplying a cooling agent to the screen, characterized in that the web is made of hygroscopic material, for example, gauze.