RU2232041C1 - Device for extinguishing combustible liquid fire into reservoir - Google Patents

Abstract

FIELD: fixed fire-fighting equipment, particularly devices used in automatic combined foam fire-extinguishing systems for combating oil and oil product fires into vertical steel reservoirs with pontoon, floating roof, and into reinforced concrete reservoirs for oil industry.

SUBSTANCE: device has low-expansion foam generator and foam container. Foam generator includes body and nozzle for supplying foam-generation solution into body. Foam generator has orifice for air suction into body. Nozzle is formed as multiple spray nozzle. Foam generator body has mixing chamber with inlet means located opposite to nozzle and outlet means connected with foam container. Foam container has foam outlet for foam entrance into reservoir made at least as two slot-like orifices. One slot-like orifice provides supplying of flat fan-shaped jet to combustible liquid into reservoir. Another slot-like orifice applies flat fan-shaped jet to reservoir wall. Sealing breakable diaphragm, which may be ruptured under the foam pressure action is installed between foam outlet of foam container and mixing chamber. For device testing device has plug locatable between breakable diaphragm and low-expansion foam generator and orifice closed by lid and formed in foam container in front of plug.

EFFECT: increased fire-fighting efficiency due to producing foam with expansion ratio of not less than 8.

2 cl, 2 dwg

Description

The invention relates to stationary equipment for extinguishing fires, in particular to devices used in combined automatic systems for foam fire extinguishing of oil and oil products in vertical steel tanks with a pontoon, with or without a floating roof, and also in reinforced concrete tanks, and can be used in oil industry.

Known devices for extinguishing a combustible liquid in a tank, similar to the claimed and described in the literature (1) and (2). The device (1), as well as the device (2), contains a low-foam generator and a foam tank. The low-foam generator of the device (1) or (2) includes a casing in the form of a pipe, at one end of which a nozzle (nozzle) is installed, and in the casing wall there is a perforated plate for air intake into the casing (1) or several holes made separately in the casing for supplying to the generator of low-level air foam, as described in the literature (2).

Inside the housing is a mixing chamber, one end of which is located opposite the nozzle (nozzle), and the other end is connected to a foam container. The foam container is made in the form of a cylindrical tank and has a foam outlet mounted on top of the side wall of the tank so that it is at a certain (not less than 50 cm) height above the combustible liquid. The foam outlet, which is a foam nozzle, is made in the form of a pipe, one end of which is connected to the foam container, and the other is rounded towards the wall inside the tank. It is assumed that the design of the foam outlet will evenly direct the flow of foam along the tank wall to the surface of the combustible liquid inside the tank without spraying. Between the foam exit from the foam container to the tank and the mixing chamber connected to the foam container, a septum in the form of a glass diaphragm is installed to prevent the flammable vapors of flammable liquid from leaving the tank through the foam container to the low-foam generator and the associated foaming agent supply system and into the environment at a time when the low-foam generator is in its initial non-operational state. In the event of a fire in the tank and the automatic fire extinguishing system triggering, the foaming agent water solution passes through the nozzle (nozzle) of the low-foam foam generator into the mixing chamber, entraining air entering through the perforated plate on the wall of the low-foam foam generator body (1). The device (2) air enters through several separate holes in the wall of the housing of the generator of low-level foam. In the mixing chamber, pricing takes place. The resulting foam fills the cavity of the foam container. The glass diaphragm breaks under burning conditions, and the pressure of the foam allows its broken parts to exit into the tank with a combustible liquid. Foam enters the reservoir through the foam nozzle, which is directed to the wall of the reservoir (1, 2).

The disadvantages of the devices (1) and (2) are the following. Firstly, the required foam ratio of at least 8 according to fire safety standards is unstable. Secondly, the jet emerging from the foam nozzle is erratic and highly fragmented and does not have a clear direction to the wall inside the tank with combustible liquid or to the oil mirror near the wall inside the tank, or to the annular gap between the tank wall and the pontoon or floating roof, which some types of tanks are equipped to reduce the evaporation of the combustible liquid stored in them. That is, a significant part of the foam does not reach its destination, which reduces the effectiveness of fire fighting. Thirdly, parts of the broken glass diaphragm clog the foam chamber and the foam exit from the foam chamber to the reservoir, which reduces the reliability of the device. In addition, fragments of the glass diaphragm can get into the pontoon or floating roof shutter made of elastic material and damage it.

The device (2) was adopted as a prototype.

The objective of the invention is to increase the efficiency of fire extinguishing by the device due to the stable achievement of the foam multiplicity of not lower than 8 according to fire safety standards and the creation of clearly directed fan jets in the desired zone of combustible liquid and on the tank wall, as well as improving the reliability of the device.

This task is achieved by improving the design of the nozzle of the low-foam generator and modifying the output for the foam of the foam container, as well as by changing the material of the sealing partition, and therefore the principle of its destruction.

Like the prototype, a device for extinguishing a combustible liquid in a tank contains a low-foam generator and a foam container, while the low-foam generator is made in the form of a housing with a nozzle for supplying a foaming agent solution to the housing and with an opening for supplying air to the housing, a mixing chamber, the input of which installed in the housing opposite the nozzle, and the output is connected to a foam container having an exit for foam into the tank and a sealing wall between the exit for foam from the foam container to the tank and the mixing chamber with the possibility of fracture during fire fighting.

Unlike the prototype, the nozzle is multi-jet, and the exit for foam from the foam container to the tank is in the form of at least two slit-like openings with the possibility of feeding flat fan jets with one of them on a combustible liquid, and the other on the inner wall of the tank, this sealing wall is made in the form of a membrane, bursting under the action of foam pressure.

For testing the device, the foam container may contain a plug installed between the bursting disc and the low-foam generator, and an opening with a lid located on the foam container before the plug.

The device is shown in figures 1 and 2 with the following notation: 1 - a reservoir with a combustible liquid, 2 - a low-foam generator, 3 - a foam container, 4 - a low-foam generator body, 5 - a nozzle for supplying an aqueous solution of a foaming agent to the body 4, 6 - hole for supplying air to the housing 4, 7 — mixing chamber, 8 — input of the mixing chamber, 9 — output of the mixing chamber, 10 — hole for the exit of foam from the foam container 3 into the tank 1 to the combustible liquid, 11 — hole for the exit of the foam from the foam capacity 3 on the inner wall of the tank 1, 12 - times yvnaya pressure under the action of a foam membrane, 13 - a lining for the membrane 12, 14 - blade 15 - hole 16 - a cover.

A device for extinguishing a combustible liquid in a tank 1 comprises a low-foam foam generator 2 and a foam container 3. A low-foam foam generator 2 includes a housing 4. The nozzle 5 for supplying a foaming agent solution to the housing is multi-jet, that is, it allows to obtain a foaming agent when passing through it two or more jets of this solution. Multi-jetting is achieved, in particular, by making a nozzle in the form of two or more nozzles located next to each other, the dimensions of which make it possible, in the aggregate of the jets created by them, to obtain the desired flow rate for an aqueous solution of a foaming agent in a low-foam foam generator 2. A multi-jet stream of an aqueous solution of a foaming agent nozzles, it better captures air and mixes with it, since the total outer surface of the received jets is larger than the surface of one jet, as in the prototype (2), which contributes to a stable Nome obtaining expansion foam is not less than 8 according to the fire safety requirements.

To supply air to the housing 4 of the generator of low-level foam 2 in the inventive device, an opening 6 is provided.

In a specific embodiment of the device, several openings 6 are arranged in two rows encircling the housing 4.

To mix the foaming solution supplied through the multi-jet nozzle 5 and the air supplied through the hole 6 in the housing 4 of the low-foam foam generator 2, the inventive device comprises a mixing chamber 7. Inlet 8 of the mixing chamber 7, provided for the foaming solution and air to enter the mixing chamber 7 is installed in the housing 4 opposite the multi-jet nozzle 9. And the outlet 8, from which the foam obtained in the mixing chamber 7 exits, is connected to the foam container 2. The foam container 2, in turn, has an exit for foam into the reservoir 1, made in the form of at least two slit-like openings 10 and 11, allowing to create a flat fan-shaped jet. In addition, the hole 10 is configured to supply a flat fan stream to a combustible liquid in the tank 1, for example, into the annular gap between the wall of the tank 1 and the pontoon (floating roof), to the combustible liquid trapped on the pontoon (floating roof), to the mirror of the combustible liquid near the wall inside the tank 1 that does not have a pontoon (floating roof). And the hole 11 is made with the possibility of feeding a flat fan stream to the inner wall of the tank 1. The holes 10 and 11 can be made, for example, in the form of narrow long slots in the wall of the foam container 3, straight along the length or rounded, or any other provided direction, with the edges protruding from the foam container in such a way as to give the necessary direction to the jet exiting the opening 10 or 11 of the foam. Or, the openings 10 and 11 can be made, for example, round, square, rectangular or any other shape, while a cover is imposed on them with a gap so that a gap is formed between the edge of the cover and the edge of the hole, which creates a flat fan-shaped stream and directs this spray on a combustible liquid in the tank 1 (hole 10) or on the wall of the tank 1 (hole 11). The slit-like openings 10 and 11 of the inventive device, compared with the round nozzle of the prototype (2), allow to increase the length of the foam jet perimeter of the reservoir 1. For example, when the slot-like openings in a particular device are 6 meters above the pontoon, the length of the foam jet the perimeter of the tank was 15 m. A similar advantage of slit-like openings reduces the number of fire extinguishing devices installed on the tank 1.

The bursting disc 12 serves to prevent the exit of explosive and flammable vapors of flammable liquid through the foam container into the low-foam foam generator 2, and then into the environment and into the foam blowing agent. Therefore, the bursting membrane is hermetically installed in the foam container between the exit for the foam from the foam tank into the tank 1, that is, the openings 10, 11, and the mixing chamber 7 of the low-foam foam generator 2. The bursting membrane 12 can be made, for example, in the form of a PTFE film, which hermetically installed across the foam container 3 between the holes 10, 11 and the mixing chamber 7 (figure 2). In a particular embodiment, the rupture disc 12 is provided on both sides with gaskets 13 and a knife 14, so that the fluoroplastic film of the rupture disc 12 is pulled onto the knife 14 under the influence of foam entering the foam container 3 during fire fighting and is torn. The gaskets 13 protect the bursting disc 12 from accidental damage and cutting through the knife 14 installed next to it before the fire fighting begins.

The device may include a plug (not shown) installed between the bursting disc 12 and the low-foam generator 2, and an opening 15 with a cover 16 for testing the device. The hole 15 with the cover 16 are located on the foam container 3 to the plugs. The cap, sealing the internal cavity of the tank 3, prevents the exit of the foam through the bursting disc 12 during testing of the device. The hole 15 with the cover 16 removed serves to exit the foam during the testing of the device.

The device operates as follows.

In the event of a fire and the operation of the combined automatic fire extinguishing system, the foaming agent solution is fed through the solution line to the low-foam foam generator 2, namely, into its body through the multi-jet nozzle 5. The multi-jet nozzle 5 forms two or more jets of the foaming agent, depending on the version. Behind the nozzle 5, these jets of the blowing agent solution are fed into the mixing zone with the air entering through the opening 6 into the housing 4. Since the nozzle 5 forms several jets, and not one, as in the prototype, more efficient air capture by the same as in the prototype (2), the volume of the foaming agent solution, which ultimately leads to the stable production of foam of the required multiplicity of at least 8 according to fire safety standards. After passing through the multi-jet nozzle 5 and mixing with the air entering through the hole 6 in the housing 4, the flow of the foaming agent solution takes the form of a semi-submerged, semi-free stream with a clearly defined core and diverging part. The main part of the jet enters the mixing chamber 7, where it is generated into the foam of the required multiplicity not lower than 8. From the low-foam foam generator 2, the foam enters the foam container 3 and fills it up to the bursting membrane 12, which hermetically seals the foam container 3 from the explosion of explosive vapors and flammable vapors of flammable liquid. At the moment when the foam pressure reaches a predetermined value (in a specific embodiment of the device, from 0.01 to 0.1 MPa), the bursting membrane 12 breaks through, and the foam flows further through the foam container 3 to the holes 10 and 11. Through the hole 10, the foam enters in the form a flat fan stream onto a combustible liquid, for example, onto a mirror of a combustible liquid near the wall of the tank 1 or into the annular gap zone between the wall of the tank 1 and the pontoon (floating roof), if the tank is equipped with it (her), or onto a combustible liquid spilled over a sweat (floating the roof). Through the hole 11, the foam enters the wall of the tank 1.

To test the device in the foam chamber 3, a plug is installed between the bursting membrane 12 and the low-foam generator 2, the lid 16 is removed and the hole 15 is opened. From the low-foam foam generator 2, the foam enters the foam container 3, and then into the hole 15.

Thus, the inventive device for extinguishing a combustible liquid in a tank is more effective than the prototype (2), since it allows you to stably obtain the required foam ratio of at least 8 and clearly direct the foam stream to the desired fire extinguishing zone, for example, to the tank wall or the annular gap zone between the tank wall and the pontoon or floating roof, which the tank can be equipped with, or to a flammable liquid spilled over the pontoon (floating roof), or to a mirror of flammable liquid near the wall ervuara. At the same time, the length of the coverage of the perimeter of the tank with a foam jet increases due to the hole design, which also increases the efficiency of fire fighting and reduces the number of fire extinguishing devices installed on the tank.

A bursting membrane made of a bursting material, for example a fluoroplastic film, cannot clog, in contrast to the shattered glass diaphragm of the prototype (2), a fire extinguishing device and prevent foam from escaping from the device, which increases the reliability of the inventive device for extinguishing a combustible liquid in a tank.

LITERATURE

1. The brochure. Low-foam foam generator, stationary, integrated with a foam chamber, for supplying foam from above with STO type complete with SK type foam nozzle, Cassialanza & C, 1999

2. The brochure. Foaming chamber SC model. Foam feeder model VF, company K.S. Anticendendi, 1998

Claims (2)

1. A device for extinguishing a combustible liquid in a tank, comprising a low-foam generator and a foam container, the low-foam generator being made in the form of a housing with a nozzle for supplying a foaming agent solution to the housing and with an opening for supplying an air into the housing of the mixing chamber, the input of which is installed in the housing opposite the nozzle, and the outlet is connected to a foam container having an exit for foam into the reservoir and a sealing wall between the exit for foam from the foam reservoir to the reservoir and a mixing chamber, made with the possible destruction during fire extinguishing, characterized in that the nozzle is multi-jet, and the exit for foam from the foam container into the tank is in the form of at least two slit-like openings with the possibility of feeding a flat fan stream with one of them to a combustible liquid in the tank and the other - on the inner wall of the tank, while the sealing wall is made in the form of a membrane, bursting under the action of foam pressure. 2. The device according to claim 1, characterized in that for testing the device it contains a plug made with the possibility of installing between the bursting disc and the generator of low-level foam, and an opening with a lid located on the foam container to the plug.

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