WO2016071869A1

WO2016071869A1 - Valve for mist spray heads

Info

Publication number: WO2016071869A1
Application number: PCT/IB2015/058573
Authority: WO
Inventors: Maurizio Grande
Original assignee: Maurizio Grande
Priority date: 2014-11-07
Filing date: 2015-11-06
Publication date: 2016-05-12

Abstract

The invention relates to a valve for atomizing heads comprising a body (10), a chamber (11) produced in the body (10), at least one inlet duct (13), at least one outlet duct (14), in communication with said chamber (11), to supply the pressurized liquid toward atomizing means, a plug (30), movable along a direction of movement (X), interposed between the inlet duct (13) and the chamber (11) and a heat sensitive release device (40), wherein said plug (30) comprises at least one gasket (32) in contact with a sealing surface (16) of the chamber (11), where said gasket (32) has at least one of thrust surface (34) facing the inlet duct (13) so that the force exerted by the pressurized liquid on said thrust surface (34) maintains said gasket (32) pressed against said sealing surface.

Description

TITLE

"VALVE FOR MIST SPRAY HEADS"

DESCRIPTION

The present invention relates to a valve for an atomizing head and more in particular for an atomizing head used in a fire extinguishing system. More in detail, the invention relates to an atomizing head for fire extinguishing systems of buildings, dwellings, large vessels and closed areas in general.

It is known that the use of jets of finely atomized water (with 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 parts and objects inside rooms not directly affected by the flames.

To generate these jets of atomized water there are known atomizing nozzles operating at very high pressures, generally comprised between 100 bar and 200 bar, or even higher. An atomizing head, used for extinguishing fires, generally comprises a body connectable to a water supply network of the fire fighting system, on which there are mounted one or more atomizing nozzles.

Based on their structure, these heads are mainly classified in two categories: open type and closed type, known in jargon as "sprinklers".

The former are generally used in "deluge" fire fighting systems. These systems are provided with a certain number of heads connected to a same branch of the water supply network of the system, which remains empty until it starts to operate.

Open-type atomizing heads are described, for example, in US 5,433,383 (A), US 6,315,219 (Bl) and WO 2008/036298 (A2).

In the deluge system, an alarm sensor is connected to a pump that, in the event of a fire, supplies a water flow rate along the aforesaid branch causing simultaneous discharge from all the heads connected thereto, including heads positioned in areas not yet involved by the fire.

However, this type of system, efficacious in high risk areas, such as factories, industrial and other sheds or the like, is not suitable inside closed rooms of civil buildings, such as apartment blocks or hotels, or large vessels.

Specifically, in these contexts, the discharge of water also in rooms not directly communicating with those in which the fire has been detected (for example in different hotel rooms or ship cabins) can cause damage to clothing, furnishings and objects and may cause inconvenience to or even endanger the occupants, without determining the need. Therefore, for these environments it is preferable to use "wet pipe" systems, which are provided with closed type atomizing heads or sprinklers.

An example of a wet pipe system is described in WO 92/15370 (Al).

Unlike the first type, the pipes of these systems are maintained filled with pressurized water that reaches all the heads of the system.

Each head is generally provided with an internal valve, controlled by a heat-sensitive release device, which supplies all the nozzles mounted on the body thereof.

In wet pipe systems, the pressure of the water in the pipes is generally maintained at an intermediate value lower than the operating pressure, i.e. the pressure value when the system is in alarm mode.

In the event of a fire in a room or area of the building, the heat sensitive element of the head closest to the origin of the fire breaks, allowing the valve to open and water to .flow from the atomizing nozzles.

Following this, a sensor detects a reduction in pressure in the pipes of the system, due to the flow of water from the first head, and activates a pump that pressurizes the water to the correct operating value (typically 100-150 bar).

In these conditions, it is important for the heads in rooms or areas far from the fire, or not yet involved by it, to remain closed, maintaining the hydraulic seal.

In general, the valve that controls opening of the head comprises a sliding plug that opens or closes the passage of the water toward the nozzles. The opening travel of the plug is prevented by the heat sensitive release device. Typically, this device consists of a glass bulb filled with a liquid that, with the increase in temperature, expands until the bulb explodes at a given predetermined temperature.

When the pressure of the system exceeds a certain threshold (for example of over 10 - 20 bar), the force exerted by the water on the plug could cause breakage of the release device.

To avoid this, some prior art heads are structured so as to at least partially offset or reduce the thrust exerted by the water on said release element.

WO 92/15370 (Al) illustrates an atomizing head in which the plug is provided with a shoulder that defines an annular chamber separated from the pressurized supply line. A hole produced in the body of the plug places said annular chamber in communication with the pressurized duct. In this way, the pressure of the water in the chamber generates a thrust opposite to the opening direction of the head.

A spring is provided to open the plug when the heat sensitive release device is broken. WO 96/08291 (Al) illustrates an atomizing head in which the plug has a central duct and an upper end that, in the closed position, couples with a pad that prevents the passage of the water in the central duct. The pressurized supply duct is arranged so that in the closed position, the pressure of the water is exerted on the lateral surface of the plug and therefore does not generate a thrust on the heat sensitive element. A spring inside the central duct pushes the plug toward the open position when the heat sensitive release device is broken.

WO 95/31252 (Al) illustrates an atomizing head similar to that of WO 96/08291 (Al) in which the spring is interposed between the head of the plug and the body of the head. The prior art heads described above have some disadvantages and limitations.

Principally, these prior art atomizing heads have an excessively complicated construction.

In fact, they comprise a large number of parts to be assembled together. Moreover, these parts have complex forms that require numerous machining operations using machine tools.

All this has repercussions on production costs, which inevitably make these objects rather costly for the end customer.

Moreover, these heads are equipped with numerous gaskets to guarantee hydraulic seal in the closed position.

The gaskets used on prior art heads are generally of O-ring type and are made of rubber or plastic materials. This type of gasket is therefore subject to gradual wear that, over time, can cause a reduction of their hydraulic seal, causing leaks even when the fire fighting system is not in operation. In general, this deterioration occurs much more rapidly when the conditions of the environment in which the head is positioned are unfavourable. For example, high temperatures, dry environments and the presence of dusts in the air can have a negative effect on the duration and on the performance of the gaskets.

For correct operation, the heads therefore require periodic inspection, even if they have never been operated.

In addition to this, even before the gaskets become worn, they can still cause leaks when subjected to very high pressures, for example 200 bar or over. In this context, the object of the present invention is to propose a valve for an atomizing head that solves the problems of prior art devices.

In particular, the object of the invention is to propose a valve for an atomizing head that allows a reduction in the force exerted by the pressure of the water on the heat sensitive release device.

The object of the invention is also to produce a valve for atomizing heads with a simple construction and that is less costly with respect to those of prior art heads.

In particular, the object of the invention is to produce a valve for atomizing heads with parts that require fewer machining operations with machine tools and fewer assembly operations, with respect to those of the prior art.

A further object of the invention is to produce a valve for atomizing heads that guarantees hydraulic seal also in the presence of very high pressures, for example of over 200 bar.

Another object of the invention is to provide a valve for atomizing heads that is reliable and does not require frequent maintenance operations.

Moreover, the object of the invention is to produce a valve for atomizing heads that can also function correctly in high temperature environments, for example of over 250° C.

Finally, the object of the invention is also to propose a valve that can be integrated into the body of an atomizing head or connected to one or more open heads of a fire fighting system.

These objects are achieved by a valve for atomizing heads comprising:

a chamber produced in a body;

a coupling portion for connection of said body to a pressurized liquid distribution line; at least one inlet duct produced at the coupling portion to allow the passage of the pressurized liquid toward the chamber;

at least one outlet duct, in communication with said chamber, to feed the pressurized liquid toward atomizing means;

a plug, movable along a direction of movement, interposed between the inlet duct and the chamber;

a heat sensitive release device, in contact with the plug when the valve is in closed position.

The plug comprises at least one gasket that, when the valve is in closed position, is in contact with a sealing surface of the chamber. Said gasket has at least one thrust surface facing the inlet duct. In this way, when the thrust surface is in contact with the pressurized liquid, the force exerted by the pressurized liquid on said thrust surface maintains said gasket pressed against said sealing surface.

The friction that is created between the gasket and the sealing surface generates a friction force opposite to that exerted by the pressurized liquid. This friction force reduces the force transmitted from the plug to the heat sensitive release element, protecting it from unwanted breakage or yielding, in the valve closed temperature range.

In particular, this solution allows bulb-type heat sensitive elements, typically made of glass, to be used also in the presence of very high pressures.

In an aspect of the invention, the gasket comprises a lip, adapted to contact the sealing surface of the chamber when the valve is in closed position. The thrust surface is produced on an inner side of said lip.

In another aspect of the invention, the thrust surface develops cylindrically or in the shape of a truncated cone. The angle a, between the generatrix of the thrust surface and the direction of movement, is preferably between 3° and 15°.

This arrangement of the thrust surface allows transmission of the pressure force of the liquid along a radial direction with respect to the sealing surface.

In this way, the surface perpendicular to the direction of movement is also reduced, reducing the pressure force that acts in the direction of opening of the valve. In another aspect of the invention, the outer surface of the lip develops in the shape of a truncated cone with the diameter increasing toward an end edge.

The diameter of the end edge is preferably greater than the maximum diameter of the sealing surface. Therefore, when the gasket is disposed at the sealing surface, it is deformed. This deformation contributes to increase the thrust that the gasket exerts on the sealing surface.

Moreover, when deformed, most or all of the outer surface of the gasket adheres to said sealing surface.

The angle β, between the generatrix of the outer surface of the lip and the direction of movement, is preferably between 3° and 1 1°.

In yet another aspect of the invention, the gasket is made of a metal, preferably selected from steel, copper or aluminum.

The metal, which has a high modulus of elasticity, after deformation of the gasket allows a considerable thrust to be created on the sealing surface.

The sealing surface can also develop substantially cylindrically or in the shape of a truncated cone. The angle γ, between the generatrix of the sealing surface and the direction of movement, is preferably between 0° and 5°.

In yet another aspect of the invention, the gasket is positioned at one end of the plug. Moreover, the plug is preferably provided with an annular protrusion, positioned against the gasket, adapted to limit deformations caused by the thrust of the pressurized liquid on said gasket.

In a variant of the invention, the outlet duct develops transversely with respect to the direction of movement of the plug and emerges on the outside of the body. The valve thus configured can be connected to liquid dispensing or atomizing means, of known type. In another variant, the valve is included in an atomizing head that comprises one or more atomizing nozzles. The chamber is in communication with said nozzles through one or more outlet ducts.

Further features and advantages of the present invention will now be described with reference to a preferred, but not exclusive, example of embodiment of a valve for atomizing heads as shown in the accompanying figures, wherein:

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

- Fig. 2 is a sectional view of the valve, in closed position, according to the invention;

- Fig. 3 is a sectional view of the valve, in open position, according to the invention;

- Fig. 4 is a sectional view of the plug of the valve according to the invention;

- Fig. 5 is a perspective view of a portion of a fire fighting system provided with a valve according to the invention.

With reference to the accompanying figures, the valve, indicated as a whole with 1 , comprises a body 10.

In the variant shown, the body 10 has an elongated cylindrical shape. However, the external shape of the body 10 is not binding for its operation and can therefore be selected as a function of aesthetic or production requirements.

On one side, the body 10 comprises a coupling portion 12. The coupling portion allows connection of the valve to a distribution line 101 of a pressurized liquid, typically a fire fighting system 100 (Fig. 5). The coupling portion 12 comprises, for example, a cylindrical terminal with internal or external thread.

Inside the body 10 there is produced a chamber 1 1.

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

At least a second outlet duct 14, in communication with the chamber 1 1 , passes through the body 10 to feed the pressurized liquid toward dispensing means. Said dispensing means are typically atomizing means of the liquid. The coupling portion 12, the inlet duct 13 and the outlet duct 14 can be included in the body 10, as in the variant shown, or removably connected thereto.

In the variant shown, the outlet duct 14 emerges from the body 10 toward the outside, preferably from the lateral surface. A connector 14a can be produced at the final section of the outlet duct 14. The connector can be, for example, a threaded connector or a quick connector of known type.

According to this variant, the valve is connectable, for example, to one or more atomizing heads of a fire fighting system.

Fig. 5 schematically shows a section of a fire fighting system 100 in which a valve 1 according to the invention supplies an atomizing head 102 through a connection duct 103, in turn connected to the outlet duct 14 of the valve.

In a further variant, not shown, the valve can be included in a closed type atomizing head or sprinkler. According to this variant, one or more atomizing nozzles are mounted on the body 10. One or more outlet ducts 14 place the chamber 1 1 in communication with said atomizing nozzles.

In a variant of the invention, 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 at least one cover 21 , which closes an opening 1 1a of the chamber 1 1. The connection between the closing element 20 and the end 10b of the body 10 is preferably produced by means of a threaded joint. A gasket 22, preferably metal, is interposed between the closing element 20 and the body 10.

Alternatively, the closing element 20 can be an integral part of the body 10.

According to the invention, a plug 30 is positioned between the inlet duct 13 and the chamber 1 1 to obstruct or free the passage of the pressurized liquid toward the chamber 1 1. The plug 30 is movable with respect to the body 10, preferably, along a direction of movement X. Movement of the plug 30 along this direction therefore causes fluid communication of the inlet duct 13 and of the outlet duct 14 through the chamber 1 1.

In a preferred variant, the plug 30 comprises a stem 31 housed slidingly in the body 10. For this purpose, in the body 10 there is produced a through opening 23 from which a portion of the plug 20 projects outward. The stem 31 and the opening 15 preferably have a cylindrical section.

In the variant shown, the opening 23 is produced in the closing element 20.

Moreover, the valve comprises a heat sensitive release device 40 that, when the valve is in closed position (Fig. 2) is in contact with the plug 30.

Said heat sensitive element 40 can comprise a glass vial, filled with a liquid, that explodes at a given temperature or a bar made of a material fusible at a given temperature.

Heat sensitive release elements thus structured are well known to those skilled in the art and therefore will not be described in greater detail.

The heat sensitive release element 40 (hereinafter "release element 40") is partially housed in a support 24 connected to the closing element 20.

When the valve is in closed position, the support 24 maintains the release element 40 in contact with the end 3 lb of the stem of the plug 30 that projects beyond the body 10.

The release element 40 prevents the plug 30 from translating along the direction of movement X toward an open position of the valve.

According to the invention, the plug 30 comprises at least one gasket 32. Said gasket 32, in the valve closed position, contacts a sealing surface 16 of the chamber 1 1. The purpose of the gasket 32 is to guarantee hydraulic seal between the inlet duct 13 and the chamber 1 1. The purpose of the gasket 32 is also to generate a friction force between itself and the sealing surface 16.

The purpose of this friction force is to oppose a large part of the pressure force exerted by the pressurized liquid located in the inlet duct 13 and that tends to thrust the plug toward an open position of the valve.

In this way, the force transmitted from the plug 30 to the release element 40 is considerably reduced.

In a preferred variant of the invention, the gasket 32 is provided with a lip 33 that, in the valve closed position, contacts the sealing surface 16.

According to the invention, said lip has at least one thrust surface 34 subject to the action of the pressurized liquid. The thrust surface 34 is arranged so that the pressure of the liquid exerts thereon a thrust that contributes to maintain the gasket pressed against the sealing surface 16.

For this purpose, the thrust surface 34 is produced on an inner side of the lip 33 that remains in contact with the pressurized liquid when the valve is closed.

In this way when the pressure of the liquid in the inlet duct 13 increases, the friction force between the gasket 32 and the sealing surface 16 also increases.

The thrust surface 34 preferably develops substantially cylindrically or in the shape of a truncated cone. In this way, the resultant of the pressure force has a prevalently radial force component with respect to the sealing surface 16. This radial force component maintains the gasket 32 in contact with the sealing surface 16.

The angle a between the generatrix of the thrust surface and the direction of movement X is preferably between 3° and 15°. More preferably, said angle a is between 5° and 9°. An ideal angle a is of around 7°.

According to a preferred embodiment, the sealing surface 16 develops substantially cylindrically.

However, the sealing surface 16 can have a diameter increasing from the chamber 1 1 toward the inlet duct 13. The sealing surface 16 can therefore be slightly truncated cone shaped.

For example, the angle β between the generatrix of the sealing surface and the direction of movement X, is preferably between 0° and 5° and more preferably between 0° and 3°.

Similarly, also the lip 33 of the gasket 32 has a circular profile preferably developing in the shape of a truncated cone in which the diameter increases toward an end edge 33b.

The angle δ between the generatrix of the outer surface 33a of the lip 33 and the direction of movement X is preferably between 3° and 1 1 °. More preferably, said angle δ is between 5° and 9°. An ideal angle δ is of around 7°.

Typically, the maximum diameter of the lip 33, at the end edge 33b, is greater than the maximum diameter of the sealing surface 16.

This means that the gasket, in the valve closed position, is deformed to be able to be placed at the sealing surface 16.

Advantageously, the gasket can be made of metal. Suitable metals are, for example, steel, copper, aluminum or the like.

Preferable metals are stainless steel, such as AISI 303 or AISI 304 steel.

The thickness of the lip 33 is such as to allow the gasket to become elastically deformed to be housed at the sealing surface.

At the same time, the deformation of the lip 33 must generate a thrust against the sealing surface 16 that guarantees both hydraulic seal and the creation of a friction force to oppose the thrust of the pressurized liquid.

The gasket 32 thus produced is able to guarantee hydraulic seal at very high pressures (even over 200 bar) and at the same time reduce the thrust transmitted to the release element 40.

Therefore, the valve can be equipped with conventional release elements, for example made of glass or fusible metals, and therefore with low mechanical strength, without the risk of them yielding under the force transmitted by the plug.

In practice, the aim of the release element is to resist the force resulting between the force exerted by the pressure of the liquid in the chamber 1 1 and the resistance force transmitted by the gasket 32.

Moreover, the truncated cone shape of the lip 33 contributes to further increase the friction force that maintains the plug in the closed position.

In a variant of the invention, the gasket is positioned at one end of the plug 30.

The gasket is preferably connected to the plug by means of a screw 35 or the like.

More in detail, the gasket 32 has an annular shape with an inner lip 36. The inner lip 36 is positioned against a pin 37 projecting from the end 3 la of the stem 31.

In a variant, the plug 30 has an annular protrusion 38 positioned against the gasket 32. More in detail, the annular protrusion 38 is arranged under the gasket 32. This annular protrusion 38 supports the gasket 32 limiting the deformations caused by the thrust of the pressurized liquid in the inlet duct.

The end 31b of the stem 31 is provided with a seat 39b to house a part of the release element 40. Preferably, the seat 39b is produced on a tip 39 resting on the stem 31. When the valve opens, the tip 39 exits completely from the opening 23 produced in the closing element 20 detaching from the valve. This ensures that the plug 30 travels as far as required, along the direction of movement X, to reach the open position.

Operation of the valve according to the invention is described below.

When the valve is installed in a fire fighting system 100, the distribution line 101 feeds a pressurized liquid, typically an extinguishing liquid, into the inlet duct 14.

When the valve is closed (Fig. 2), the passage of the liquid in the chamber 1 1 is prevented by the plug 30.

Due to the friction between the gasket 32 and the sealing surface 16, the stem 31 of the plug 30 only transmits a part of the pressure force generated by the pressurized liquid to the release element 40.

The force transmitted to the release element is calibrated so that it cannot break or become deformed at ordinary temperatures (typically below 45°-50°C). When a fire develops in the vicinity of the valve, the increase in temperature causes the release element 40 to break or yield.

At this point, the resultant between the pressure force of the liquid and the friction force of the gasket 32 thrusts the plug 30 toward the valve open position (Fig. 3).

In this position, the pressurized liquid can reach the chamber 1 1 and flow through the outlet duct 14 to reach the atomizing means.

In the system illustrated in Fig. 5, the liquid passes through the connection duct 103 to supply the atomizing nozzles 104 of the heads 102.

In a variant not shown, an elastic element is arranged in the body 10 so as to exert a thrust that tends to maintain the plug 30 in closed position.

Said elastic element can, for example, comprise a spring housed in the chamber 1 1 that acts on the annular protrusion 38 of the stem 31.

The elastic constant of the elastic element can be selected as a function of the strength of the release element 40. In this way, the elastic element allows the valve to be calibrated so that the resultant between the pressure force of the liquid and the friction force does not exceed a predetermined threshold to preserve the release element 40.

The invention has been described purely for illustrative and non-limiting purposes, according to some preferred embodiments. Those skilled in the art may find numerous other embodiments and variants, all falling within the scope of protection of the claims below.

Claims

1. A valve for atomizing heads comprising:

a chamber (1 1) produced in a body ( 10) ;

a coupling portion (12) for connection of said body (10) to a distribution line of a pressurized liquid;

at least one inlet duct (13) produced at the coupling portion (12) to allow the passage of the pressurized liquid toward the chamber (1 1);

at least one outlet duct (14), in communication with said chamber (1 1), to feed the pressurized liquid toward atomizing means;

- a plug (30), movable along a direction of movement (X), interposed between the inlet duct (13) and the chamber (1 1);

a heat sensitive release device (40), in contact with the plug (30) when the valve is in closed position;

said plug (30) comprising at least one gasket (32) that, when the valve is in closed position, is in contact with a sealing surface (16) of the chamber (1 1), said gasket (32) having at least one thrust surface (34) facing the inlet duct (13) so that when the thrust surface (34) is in contact with the pressurized liquid, the force exerted by the pressurized liquid on said thrust surface (34) maintains said gasket (32) pressed against said sealing surface.

2. The valve according to claim 1, wherein said gasket (32) comprises a lip (33), adapted to contact the sealing surface (16) of the chamber (1 1) when the valve is in closed position, said thrust surface (34) being produced on an inner side of said lip (33).

3. The valve according to claim 2, wherein said lip (33) has an outer surface (33a) developing in the shape of a truncated cone with the diameter increasing toward an end edge (33b), the maximum diameter of said outer surface (33a) being greater than the maximum diameter of the sealing surface (16) so that the gasket (32), when disposed at the sealing surface (16), is deformed.

4. The valve according to claim 2 or 3, wherein the angle (δ), between the generatrix of the outer surface (33a) and the direction of movement (X) of the plug (30), is between 3° and 1 1°.

5. The valve according to any one of claims 2 to 4, wherein the thrust surface develops cylindrically or in the shape of a truncated cone where the angle (a), between the generatrix of the thrust surface (34) and the direction of movement (X) of the plug (30), is between 3° and 15°.

6. The valve according to any one of the preceding claims, wherein said gasket (32) is made of a metal selected from steel, copper, aluminum or alloys thereof.

7. The valve according to any one of the preceding claims, wherein the sealing surface (16) develops substantially cylindrically or in the shape of a truncated cone where the angle (β), between the generatrix of the sealing surface (16) and the direction of movement (X), is between 0° and 5°.

8. The valve according to any one of the preceding claims, wherein the gasket (32) is positioned at one end of the plug (30).

9. The valve according to any one of the preceding claims, wherein the plug (30) is provided with an annular protrusion (38) positioned against the gasket (32) adapted to limit the deformations caused by the thrust of the pressurized liquid on said gasket (32).

10. The valve according to any one of the preceding claims, wherein said outlet duct (14) develops transversely with respect to the direction of movement (X) of the plug (30) and emerges on the outside of the body (10).

11. An atomizing head comprising at least one atomizing nozzle and a valve according to one of the preceding claims from 1 to 9, where said atomizing nozzle is in connection with the chamber (1 1) through at least one outlet duct (14).