"MISTING NOZZLE"

DESCRIPTION

The present invention relates to an atomizing nozzle and in particular a nozzle for fire extinguishing systems inside buildings, dwellings, large vessels and closed areas in general.

It is known that the use of jets of finely atomized water (with water droplets having a diameter of less than 200 μιη), known in jargon as "water mist", is preferable to the use of conventional jets of water to extinguish fires inside buildings and especially in houses, hotels or other closed areas containing furnishings and/or valuable objects.

The effect of these very small water droplets is to very rapidly remove, through their evaporation, a large amount of thermal energy from the environment in the area on fire, lowering the temperature drastically.

Through this system it is also possible to reduce the amount of water used with respect to conventional jets, a large part of which evaporates instantly, reducing damages caused directly by the water to items and objects inside rooms not directly affected by the flames.

To generate these jets of atomized water there are known specific atomizing nozzles operating at very high pressures, generally comprised between 100 bar and 200 bar, or even higher.

US 2012/261489 Al shows an atomizing nozzle comprising:

- a body, inside which there is produced an axial duct for the passage of the water;

- a cover that closes one end of the duct and in which there is produced an outlet orifice for the atomized jet;

- a spherical or semi-spherical plug, operated by a spring, housed in the duct to close the passage of the water coming from the supply system; and

- a slider or head, housed in the duct with the ability to slide, adapted to contact the cover at the orifice.

At times the cover is made in two parts, one carrying the outlet orifice, which can be replaced if clogged or worn, and the other carrying the means for connection to the body.

In some cases, the closing plug is not present and the slider is subject only to the pressure of the water inside the duct.

Other similar atomizing nozzles are described in US 2008/0006721 , US 6,666,386, US 2013/0153687 and US 5,857,626.

Operation of these atomizing nozzles is well known to those skilled in the art and will therefore not be described in detail herein.

Typically, between the body and the cover there is provided a sealing gasket to prevent the escape of water due to the very high pressure inside the duct.

A gasket, generally supplied by the manufacturer, is also positioned at the coupling between the body and the water distribution circuit that serves one or more atomizing nozzles.

In prior art nozzles, these gaskets are generally O-ring type gaskets made of elastomeric material.

More specifically, the most commonly used materials are fluorinated polymers and in particular fluorinated terpolymers, such as those marketed by Dupont with the trademark "Viton".

These materials maintain their properties of elasticity at temperatures below around 150°-180°.

Beyond this temperature threshold, these elastomers start to polymerize, losing their elasticity and no longer guaranteeing the hydraulic seal, especially when the water pressure reaches or exceeds values of 300 bar.

An event of this kind can occur when these atomizing nozzles are used in fire extinguishing systems. In fact, the presence of fire can cause a very rapid increase in the temperature in the vicinity of the nozzles, which can become damaged before the fire is extinguished, becoming less efficient or even unusable due to the phenomenon described above.

The plug that closes the passage of the water toward the inner duct of the body is also often made of elastomeric materials such as those cited above.

This component also suffers from the same problems described previously.

In this context, the object of the present invention is to propose an atomizing nozzle that solves the problems of prior art devices.

In particular, the object of the innovation is to produce an atomizing nozzle that ensures greater reliability and better efficacy of action when used in fire extinguishing systems.

More in detail, the object of the invention is to propose an atomizing nozzle that can operate correctly even in environments with high temperatures, for example of over 200°.

The object of the invention is also to produce an atomizing nozzle that has no substantial construction complications with respect to prior art nozzles.

The object of the invention is therefore to provide an atomizing nozzle that is sturdy, simple to produce and inexpensive.

These objects are achieved by an atomizing nozzle comprising:

- a body with a coupling portion for connection of the nozzle to a pressurized water distribution line;

- a chamber produced in the body;

- an inlet duct produced at the coupling portion to allow the passage of the water toward the chamber;

- a cover that closes one end of the chamber, in which there is produced an outlet orifice for the jet of atomized water;

- a movable plug interposed between the inlet duct and the chamber;

- a slider, housed slidingly in the chamber, that carries at one end a diffuser; and - an elastic element, interposed between the plug and the slider, adapted to maintain the diffuser pressed against the cover.

A first sealing gasket is interposed between said body and said cover. At least a second sealing gasket is positioned at the coupling portion.

According to the invention, the first and the second gasket are made of metal. Preferably, said first gasket and said second gasket are made of stainless steel.

In one aspect of the invention, the first gasket comprises an external annular portion defining a first stop face and a second stop face, adapted to respectively contact the body and the cover, when these are clamped.

The first gasket also comprises an inner portion, which projects from the first stop face, defining a first conical flange that can be inserted, at least partially, into the chamber, to maintain the gasket centered.

Preferably, the external annular portion has a constant thickness. Therefore, the stop faces are substantially flat.

In a further aspect of the invention, the body comprises a terminal onto which the cover is fixed. Preferably, according to the invention, the outer diameter of the first flange is coincident with the inner diameter of the edge of the terminal.

In a further aspect of the invention, the first gasket also comprises a second cylindrical flange that projects from the second stop face and extends toward the cover. Therefore, said second flange is at the contact area between the second stop face and the cover.

In another aspect of the invention, at the base of the coupling portion there is produced a groove into which the second gasket is at least partially inserted. This groove, according to the invention, can have two conical surfaces, one inner and one outer, facing each other. In yet another aspect of the invention, the second gasket comprises an external annular portion that defines two contact faces adapted to respectively contact the upper edge of the groove and a connector of the distribution line. Preferably, said external annular portion has a constant thickness. Therefore, the contact faces are substantially flat.

The second gasket also comprises an internal annular portion that defines a first conical flange. The surface of the flange contacts the outer conical surface of the groove when the nozzle is clamped on said connector.

Preferably, the angle of the surface of the flange is of around 64° and the angle of the outer conical surface of the groove is of around 68°. The difference in the angle of the two conical surfaces allows the gasket, during clamping, to deform so that said surfaces are in contact with each other.

The objects set are also achieved by a nozzle in which the diffuser comprises a cylindrical tip with a flat head surface on which there are produced four incisions that define the same number of channels that allow the pressurized water to flow from the chamber toward the orifice.

In a preferred variant, the tip has a diameter of 1.3 mm, and the channels have a width of 0.2 mm, a maximum height of 0.21 mm and a length, measured on the axis, of 0.5 mm.

Further features and advantages of the present invention will now be described with reference to a preferred, but not exclusive, embodiment of an atomizing nozzle as illustrated in the accompanying figures, wherein:

- Fig. 1 is an exploded perspective view of the atomizing nozzle according to the invention;

- Fig. 2 is a sectional view of the atomizing nozzle according to the invention;

- Figs. 3a and 3b are the same number of side views of the gaskets

- Figs. 4a, 4b and 4c are respectively a perspective, front and side view of the slider of the nozzle, according to the invention.

With reference to the accompanying figures, the atomizing nozzle, indicated as a whole with 1, comprises a body 10 inside which a chamber 1 1, preferably cylindrical, is produced. On one side, the body 10 comprises a coupling portion 12 for connecting the nozzle to a high pressure water distribution line. The coupling portion 12 comprises, for example, a threaded cylindrical terminal.

The outer surface of the body 10 is preferably knurled to allow a better grip during clamping and release of the nozzle from a connector of the distribution line.

The chamber 1 1 is placed in communication with the distribution line through a duct 13 that passes through the coupling portion 12 and emerges at one end 10a of the body 10.

A closing element 20 is positioned at the opposite end 10b of the body 10 to close the chamber 1 1. The closing element 20 comprises a cover 21 that closes the end 1 1a of the chamber 1 1 and a ring nut 22, screwed onto a threaded terminal 14 of the body 10, which maintains the cover 21 in position.

In the cover 21 there is produced an orifice 23 from which the jet of atomized water is delivered. The diameter of the orifice 23 is around 0.2 mm.

The body 10 and the closing element 20 are made of steel, preferably stainless steel. A plug 30 is positioned between the duct 13 and the chamber 1 1 to obstruct or free the passage of the pressurized water toward the chamber 1 1. The plug 30 comprises a semi- spherical portion 31 adapted to contact a conical stop 15 produced at one end l ib of the chamber 1 1.

A slider 40 is housed slidingly in the chamber 1 1. The slider 40 comprises a cylindrical central portion 41 , with a slightly smaller diameter than that of the chamber 1 1 , and a diffuser 42 that extends from the central portion 41 toward the cover 21.

An elastic element 32, such as a spring, is interposed between the plug 30 and the slider 40. The spring 32 exerts an elastic force that tends to move the slider 40 and the plug 30 away from each other. The spring then maintains the plug 30 pressed against the stop 15 of the chamber 1 1 and the diffuser 42 against the cover 21.

When the pressurized water is fed into the duct 13, if the pressure exerted by the water on the plug 30 is greater than the pressure exerted on by the spring 32, the plug 32 moves away from the stop 15, allowing the water to flow into the chamber 1 1.

The diffuser 42 comprises a cylindrical tip 43 with a flat head surface 44. On the head surface 44 there are produced incisions defining channels 45 that allow the pressurized water to flow from the chamber 1 1 toward the orifice 23.

Atomization of the water takes place during the passage of the water through the channels 45, which have a decreasing section.

This phenomenon is well known to those skilled in the art and therefore will not be described herein.

Tests performed by the applicant showed that excellent atomization results are obtained with a diffuser with four incisions on the head surface 44, defining the same number of channels 45.

More in detail, these results are achieved with a diffuser with a tip 43 of the diameter D of 1.3 mm and with the channels 45 having a width L of 0.2 mm, a maximum height H of 0.21 mm and a length P, measured on the axis, of 0.5 mm.

These parameters ensure the generation of micro droplets of water almost all of which having the same geometric mean diameter.

Between the cover 21 and the threaded terminal 14 there is interposed a first sealing gasket 50 to prevent pressurized water from leaking from the chamber 1 1. A second sealing gasket 60 is positioned at the coupling portion 12 to prevent the leakage of pressurized water between the body 10 and a connector of the distribution line.

According to the invention the first gasket 50 and the second gasket 60 are made of metal. Preferably the gaskets 50, 60 are made of stainless steel, for example AISI 303 or 304 steel.

Gaskets thus configured can be used at high temperatures (even over 250°) without being subject to substantial deformations and without losing their mechanical properties or hydraulic seal.

In a preferred embodiment the first gasket 50 comprises an external annular portion 51 and an internal annular portion 52.

The external annular portion 51 has, preferably, a constant thickness and defines a first stop face 53 and a second stop face 54. Therefore, said stop faces 53, 54 are preferably substantially flat.

The stop faces 53, 54, respectively contact the body 10 and the cover 21. The hydraulic seal is guaranteed by these surfaces.

More in detail, the stop face 53 is in contact with the edge 14a of the terminal 14.

The internal annular portion 52 projects from the first face 53 defining a first conical flange 55. The first flange 55 extends at least partially into the chamber 1 1 to maintain the gasket centered with respect to the body 10.

For this purpose, the maximum diameter Df of the first flange 55 coincides with the internal diameter db of the edge 14a of the terminal 14. In practice, the lateral wall 55a of the first flange 55 is free from the contact with the terminal 14. The clamping force is discharged only on the flat faces 53, 54 that produce the hydraulic seal.

A second cylindrical flange 56 instead projects from the face 52 of the gasket 50. This second flange 56, which extends toward the cover 21, creates a barrier at the contact area between the surface 52 and the cover 21 contributing to improve the hydraulic seal.

The second gasket 60 is positioned at the base of the coupling portion 12.

In this area there is produced a groove 16 into which the gasket 60 is at least partially inserted. The groove 16 has an outer conical surface 16a and an inner conical surface 16b. The two conical surfaces 16a, 16b are facing each other. The outer surface 16a has the diameter increasing toward the end 10b of the body 10, while the inner surface 16b has the diameter decreasing toward the end 10b of the body 10.

Similarly to the first, also the second gasket 60 comprises an external annular portion 61 and an internal annular portion 62.

The external annular portion has two contact faces 63, 64. Said contact faces are preferably flat and parallel to each other. The first face 63 contacts an upper edge 17 of the groove 16 when the nozzle is clamped on a connector (not shown) of the pressurized water distribution line. The second face 64 contacts a respective part of the connector.

The internal annular portion 62 projects from the face 63 defining a first conical flange 65. The flange 65 is housed fully in the groove 17. The conical surface 65b of the flange 65 contacts the outer conical surface 16a of the groove 16 when the nozzle is clamped on the connector.

According to the invention, the angle of the surface 65b of the flange 65 is less than the angle of the outer conical surface 16a.

According to a preferred variant, the angle a of the surface 65b of the flange 65 is of around 64° while the angle β of the outer conical surface 16a is of around 68°.

During clamping, the gasket 60 deforms so that the surfaces 16a and 65b are in contact. A second conical flange 66, adapted to be inserted into the connector, projects from the opposite face 62.

The surface 65b of this second flange has an angle of approximately 44°.

According to the invention, the plug 30 is also made of metal, and more specifically stainless steel. In this way the nozzle 1 is made entirely of metal material, without parts in plastic or elastomeric materials that could deteriorate if exposed to high temperatures, or in any case exceeding 150°.

In the event of a fire, the nozzle thus conceived is much more reliable than prior art nozzles. Moreover, the nozzle of the invention can be washed or also treated with chemical products without compromising its operation and reliability.

The invention, as described and illustrated, may be subject to various modifications and variants, all of which fall within the scope of the inventive concept; furthermore, all the details may be replaced with other technically equivalent elements.