WO2020012517A1

WO2020012517A1 - Anti-flooding duct with safety valve for supplying water

Info

Publication number: WO2020012517A1
Application number: PCT/IT2019/050164
Authority: WO
Inventors: Roberto ZORZI
Original assignee: Seprio Plast Zn S.R.L.
Priority date: 2018-07-12
Filing date: 2019-07-11
Publication date: 2020-01-16
Also published as: EP3821071A1; EP3821071B1

Abstract

An anti-flooding duct with safety valve comprises an internal pressurised water intake hose; an external safety hose (8) coaxial to the internal hose for the entire length of this internal hose from the safety valve connected to the water distribution hose (11) to the outlet end (7) and watertight with respect to the external environment; and has, amidst the connection point of the water distribution hose (11), a valve body (5, 32) of the safety valve (1), a permanent magnet (16) which is slidable outside the valve body in a direction parallel to the duct (12) of the valve body, i.e., parallel to the sliding axis (C) of a shutter body made of a ferromagnetic material and slidable within a first part (13) of the duct (12), the shutter body is positioned with the magnetic interaction in the said first part; the opening position of the safety valve (1) is made by factory default and maintained by a member which is sensitive to the flooding of the external safety hose (8) which includes at least one water-sensitive sponge (21, 22) to undoubtedly define the said opening position of the safety valve (1), using the magnetic action of the permanent magnet (16), acting on the shutter body, and kept away by a sealing ring (27) inserted at the end of said first part (13) of the duct (12) inside the valve body (5, 32); the valve body being made of a non- ferromagnetic material; the coaxial space between said internal intake hose and the external safety hose (8) is in hydraulic connection with an interstice (26) for housing the said sponge. Different constructive forms of the internal mechanisms of the safety valve are described.

Description

ANTI-FLOODING DUCT WITH SAFETY VALVE FOR SUPPLYING WATER

Field of application

The present invention relates to an anti-flooding duct with safety valve for supplying water, i.e. , a hose provided with a mechanical safety valve to prevent the water from flowing out in water supply hoses, generally in household appliances such as a washing machine and a dishwasher, if the apparatus is constantly connected to the water supply system with pressurised water supply: the duct, as is known, comprises an internal water intake hose and an external one for collecting any leakage from the previous one and a valve for the conditioned block of the water supply in the event of a flood in the external hose.

Prior art

The background art comprises anti-flooding ducts with safety valve for supplying water in which a mechanically operated valve is provided in order to block the flow of water in the internal supply hose in the event of a water leakage which floods the external safety hose.

From the document IT 1192008 B valves for shutting off the water supply to the inner tube are known, wherein the flooding sensitive member is a swellable sponge which, in the presence of water, considerably increases its volume and, by compressing a spring, actuates for closure a shutter for closing the valve supplying water to the internal hose. Furthermore, in this document, a safety valve is also described, in which the flooding sensitive member is a yielding sponge: after having been wetted by the flooding of the external tube, the sponge yields and is compressed under the action of a spring, thereby releasing the shutter of the safety valve; the water pressure closes the safety valve preventing the further flow of water in the internal supply hose.

The prior art also comprises the document IT 1312179 B in which the shutter of the safety valve is paired to a first permanent magnet which, when opposite to a corresponding second permanent magnet with inverse polar arrangement, is kept open. The second magnet is associated with a movable member in the base of the safety valve which, in turn, is displaced from the assembly position after the flooding of the external hose: the moving force of the movable member is obtained with a swellable sponge which, obviously, in the event of flooding, moves the movable member so as to cause the opposing magnetic fields of the two magnets to be out of alignment. The effect is to free the position of the two magnets and, also due to the rotation of the second magnet when the movable member moves, the first magnet is no longer hindered in moving; on the contrary, the rotated magnetic field of the second magnet attracts it and releases the shutter of the safety valve which closes, due to the water pressure in the supply duct, blocking the flooding.

The prior art also includes the document EP 609842 A1 , wherein the shutter of the safety valve of a pressurised water intake hose is paired to a first permanent magnet; a second external tube wraps the first tube with pressurised water throughout the length of the first tube. A second permanent magnet, with inverse polar arrangement, is opposite and aligned correspondingly to the first magnet, but kept at a sufficient distance to avoid the mutual interference of the magnetic action. The second magnet is associated with a movable member in the base of the safety valve which, in turn, is displaced from the assembly position after the flooding of the external hose: the moving force of the movable member is allowed by an yielding dry sponge which, obviously, in the event of flooding and by means of a spring kept compressed, allows the movable member to move, so as to bring the opposing magnetic fields of the two magnets closer. The effect is to bias the first magnet, connected with the shutter, to move to close the shutter of the safety valve, which closes, against the water pressure in the supply duct, blocking the flooding.

Part of the prior art is also the document US 2014/0158226 A1 , wherein the safety valve is made with a shutter kept open by means of a pin for stopping the sliding of the shutter itself which prevents its closure. The said pin is associated and kept in the position taken by a member which is sensitive to the flooding of the external hose, when the pressurised water supply internal hose is leaking; the sensitive member, indeed, is a membrane connected and concentric to said pin and which causes the axial movement of the pin in the event of flooding of the external safety hose, to which it is hydraulically connected only on one side of the membrane: by changing the humidity on the wet side of the membrane, flooding acts by deforming it and moving the pin axially from the locking position of the shutter of the safety valve which closes, stopping the water supply and therefore the flooding. The movement directions of the said pin and of the shutter are necessarily right-angled

Furthermore, in the prior art, there are anti-flooding ducts with safety valve for supplying water in which the valve is controlled by electrical logic and shutter actuating relay, thus they do not fall within the specific art of the present invention relating to purely mechanical valves.

Moreover, the said mechanical valves in which the opposition to the movement of the shutter of the safety valve is achieved with a spring, the deformable members, i.e. , the water swellable sponges, must also act against the reaction of the contrast spring, thus requiring abundant sizing of the sponge that must implement both the force to move the pin or the shutter and the force to overcome the compression of the countering spring, as well. Otherwise, the yielding sponges carry out the actuation by means of a spring which compresses them by moving the pin to release the shutter of the safety valve. Such arrangement achieves a minimum sizing only with the actuation of the pin which is right-angled with respect to the shutter of the valve.

Likewise, the mechanical safety valves in which the two magnets mounted with opposing magnetic fields are present have operating instability and significant overall dimensions in a radial direction with respect to the water supply hose. The internal movement of the movable member which carries the second magnet develops in a perpendicular direction with respect to the shuttering movement direction of the valve, performed by the first magnet, so as to create outward radial overall dimensions with respect to the casing of the safety valve. Furthermore, the movement generated by the thrust of the sponge expandable with the flooding may be anticipated in the safety valves built according to the document IT 1312179 B due to the rotation of the second magnet, even in the event of an abrupt movement in the assembly of the hose to the current-using apparatus, so as to make the hose itself useless since the resulting misalignment of the magnets causes the early clogging of the valve. Finally, a further limitation of the prior art may also be found in the safety valves built according to the document US 2014/0158226 A1 , since the operation of the release pin of the shutter in the mechanical safety valve must take place with the horizontally movable shutter always requiring the construction of the movement axis of the release pin in a direction perpendicular to the movement axis of the shutter of the safety valve resulting, in each different constructive version illustrated in the document, in significant radial overall dimensions with respect to the external safety hose.

This background art is susceptible of considerable improvements with regard to the possibility of manufacturing an anti-flooding duct with safety valve for supplying water, which overcomes the aforementioned limits of the prior art.

The technical problem underlying the present invention is therefore to provide an anti-flooding duct with safety valve for supplying water, which makes it possible to reduce the overall dimensions of the external casing of the supply hose as a whole, i.e., including also the external safety hose.

Furthermore, it is necessary to improve the prior art to provide the safety valve in which a minimum number of parts is able to provide the valve locking operation by moving in a direction parallel to the axis of the internal supply hose and to the external safety hose, so as to achieve the minimum radial overall dimensions with respect to the coaxial hoses.

An object inherent in the above technical problem is to achieve the control of the actuation of the shutter of the safety valve in a direct and limited manner and with moving parts parallel to the axis of the water supply hose.

A further and not least object of the present invention is to provide a mechanical safety valve sensitive to the flooding of the external safety hose, but at the same time insensitive to the position where the valve is mounted on the pressurised water intake hose of the home water system.

Summary of the Invention

This problem is solved, according to the present invention, by an anti-flooding duct with safety valve for supplying water comprising: an internal pressurised water intake hose; an external safety hose coaxial to the internal hose for the entire length of this internal hose from the safety valve connected to the water distribution hose to the outlet end and watertight with respect to the external environment; characterized in that, amidst the connection point of the water distribution hose, a valve body of the safety valve comprises a permanent magnet which is slidable outside the valve body in a direction parallel to the duct of the valve body, i.e. , parallel to the sliding axis of a shutter body made of ferromagnetic material and slidable within a first part of the duct; the shutter body is positioned with the magnetic interaction in the said first part; the opening position of the safety valve is made by factory default and maintained by a member which is sensitive to the flooding of the external safety hose which includes at least one water-sensitive sponge to undoubtedly define the said opening position of the safety valve, using the magnetic action of the permanent magnet, acting on the shutter body, and kept away by a sealing ring inserted at the end of said first part of the duct inside the valve body; the valve body being made of a non- ferromagnetic material; the coaxial space between said internal inlet hose and the external safety hose is in hydraulic connection with an interstice for housing the said sponge.

In a further constructive form, the permanent magnet - the first magnet - is housed in a slider lateral with respect to the valve body and made slidable thereon using guiding means connected to the valve body.

Besides, in an improved constructive form, at least one yielding sponge is inserted between the first permanent magnet and a second fixed abutment of the valve body to counter at least the hydraulic thrust of the water flowing within the valve body before flooding.

Moreover, in a further variant of the above constructive forms, at least one swellable sponge is inserted between the first permanent magnet and a first fixed abutment of the valve body, to overcome, upon flooding, the resistances to the parallel sliding of the first magnet with respect to the valve body.

Besides, in a specific improved implementation, the first permanent magnet is housed within a seat in the slider which is provided with a partition abutment for contacting the said yielding and/or swellable water-sensitive sponge.

Furthermore, in a preferred constructive variant, the shutter body is comprised of a shutter ball, and the shutter body or the shutter ball is made with a permanent magnet, the second magnet.

Finally, the implementation of a preferred constructive form has the radial overall dimensions of the valve body, determined by half-shells closing it, being equal to or slightly greater than the external diameter of the external safety hose.

Further features and the advantages of the present invention, in providing an anti-flooding duct with safety valve for supplying water, will be manifest by the following description of a constructive form and embodiment, given by way of non-limiting example, with reference to the five attached drawing tables.

Brief description of the drawings

Figure 1 shows a perspective and schematic view of an open external casing of a mechanical safety valve against the flooding of the external safety hose inserted within this casing;

- Figure 2 shows a perspective and schematic view of a pressurised water supply hose mounted on the pipeline of the home water system;

- Figure 3 shows a schematic longitudinal section of the safety valve inserted in the water supply hose in preceding Figures, so as to show the position of the valve with the ball shutter, which is free, yet controlled, inside the valve body, in the opening position;

- Figure 4 shows the schematic longitudinal section as in Figure 3, which represents the position of the mechanism when the yielding sponge yields and the swellable sponge swells following the flooding of the external safety hose; the ball shutter is housed in the section for the flow of water in the valve body against the seal to close the passage therefor;

- Figure 5 shows a schematic longitudinal view as shown in Figure 3, seen from the outside of the valve body, wherein the position of the movable slider with the safety valve kept open by the position of the first magnet, integral with the movable slider, defined by the aforementioned sponges, is highlighted;

- Figure 6 shows a schematic view as in Figure 5, but with the mechanism of the safety valve operated by the water leakage, i.e. , with the movement of the movable slider with the first magnet and, consequently, of the second ball magnet, acting as a shutter, inside the valve body and not visible herein, for obstructing the flow of pressurised water;

- Figure 7 shows a schematic and exploded perspective view of the components of the mechanism of the safety valve according to the invention in the constructive form without a casing outside the valve, i.e., the movable slider for leading the first magnet contained only by the external safety hose;

- Figure 8 shows a schematic and exploded perspective view of the components of the mechanism of the safety valve in a second constructive form, wherein the guidance of the movable slider is performed by means of an arched cover for containing the movable slider on the valve body thereof.

Detailed description of some embodiments

In Figure 1 it may be seen a safety valve 1 , according to the invention, housed upstream of the inlet end 2 of a supply hose 3 with mechanical safety visible in Figure 2, considered as a whole. The supply hose comprises an internal hose, not shown and connected to a gripping spout 4 of the valve body 5 and terminates with an outlet end 7, possibly curved as a pipette, connected to a nut 6, clamped to the apparatus to be supplied with constantly pressurised water. An advantageously corrugated external safety hose 8 is externally and coaxially associated with the said internal hose, for wrapping the internal hose, and connected to the valve body 5, with wraparound and watertight semi-shells 9 made during the assembly; in the outlet end 7 both the internal hose and the external safety tube are clamped to the end connection 10, shown here with a pipette and nut 6. At the inlet end 2, it is connected with the valve body 5 to the water distribution hose 11 of the home system by means of a typical threaded nut 6.

In Figures 3 to 6 the valve body is internally drilled by a duct 12 whose first part 13 houses a filter 14 and a longitudinal guide seat 15 of a ball shutter 17; the shutter ball consists of a permanent magnet - the second permanent magnet - kept in the position as in Figure 3, open, due to the magnetic attraction generated by a first permanent magnet 16, housed outside the valve body 5, but in a sliding side 18 formed parallel to the said internal duct 12 of the valve body 5 and close to the sliding axis C of the ball 17 - the second permanent magnet and valve shutter - in the guide seat 15.

Moreover, the first permanent magnet 16 is housed in a slider 19, slidable on the side 18 and connected, in the part opposite to the position of the seat 20 of the first magnet, to swellable sponges 21 and a yielding sponge 22 arranged as opposed to the partition abutment 23 in said opposite part of the slider 19; the housing seat of the sponges is delimited by fixed abutments in the side of the valve body 5: a first fixed abutment 24 determines the holding point of the swellable sponges 21 , and a second fixed abutment 25 determines the holding point of the yielding sponge 22.

Figures 3 and 5 show the open position of the safety valve 1 , while Figures 4 and 6 show the closed position of the safety valve, following an actuation of the closing mechanism of the ball shutter 17 as a result of the flooding of the interstice 26 between the two hoses: the internal hose and the external safety hose 8. The aforementioned sponges are affected by the effect of water, so as to compress the yielding sponge 22 and cause the swellable sponge(s) 21 to swell. The effect is a movement of the partition abutment 23 which drives the slidable slider 19 along the sliding side 18 of the permanent magnet, the first magnet 16; the action of the magnetic field generated by the magnet passes through the wall of the valve body 5, advantageously made of plastic material, and draws the ball 17 - the second magnet and shutter of the safety valve 1 - along the guide seat 15 against a sealing ring 27, thus closing the passage, in the supply direction D, and stopping the water leakage.

Similarly, Figures 7 and 8 show two different constructive forms of the safety valve 1. In Figure 7, on the valve body 5 there is a typical gasket 28 in the connection with the water distribution hose 11 ; moreover, the slider 19 is provided with guides 29 which are inserted, during the assembly, in slots 30 in the valve body to keep the slider within the guide without further members associated with the said valve body 5; for the sake of completeness, the sealing ring 27 is shown herein as a V-ring 31.

Furthermore, in Figure 8, the valve body 32, of a modified constructive form, has a different arrangement of the slider 33, kept in contact with the sliding side 18, by means of an arched cover 34, in turn inserted on the valve body with teeth 35 into slots 36; moreover, in order to make accessible to flooding, from the interstice 26, the yielding 22 and the swellable 21 sponges, the second fixed abutment 25 has a truncation 37. Moreover, the sealing ring 27 is shown herein by an O-ring 38 and, for the sake of completeness, a pre-filter 39 is placed upstream of the filter 14, when it is required to filter more the supply water.

The use of the anti-flooding duct described earlier is implemented by mounting the supply hose 3, considered as a whole, onto the water distribution hose 11 of the home installation and the other end, the end connection 10, to the household appliance which needs to be supplied with constantly pressurised water. The safety valve 1 , housed within the connection upstream of the supply hose 3, is by factory default in the opening condition, i.e., as depicted in Figures 3 and 5. The ball shutter 17 - the second magnet - is kept in the opening position depicted by the magnetic field generated by this second magnet and by the first magnet 16, which is housed within the seat 20 of the slider 5 or 33. The depicted position, which keeps the shutter ball 17 away from the sealing ring 27, is achieved by the two magnet fields of the permanent magnets attracting each other. The first permanent magnet 16 has a unidirectional magnetic field with a fixed direction, while the second magnet 17 - the shutter ball - can rotate in the guide seat 15 positioning itself with its magnetic field for the attraction with the magnetic field of the first magnet 16. The force generated by the attraction overcomes the actions of gravity or impacts to which the shutter ball 17 - the second magnet - due to its mass, can be subjected, and prevails over the dragging thrust due to the supply of pressurised water, typical of the non-return ball valves. The position of the slider 19 or 32, being defined by the wetting state of the sponges, the yielding 22 one and the swellable 21 one, is a definite position, since the dry sponges behave as rigid members with fixed size which, given the limited masses involved of the slider 19 or 32, of the first magnet 16 and of the second magnet 17 - the shutter ball - allow with certainty the fixed definition of the opening state that overcomes the action of the force of gravity and of possible impacts or shaking to which the safety valve 1 may be subjected before the implementation in the connection of the household appliance for which it is intended.

As a result, the described mechanism for controlling the opening/closing of the safety valve 1 is insensitive to the position of the supply hose 3, thus also being usable with the supply direction D contrary to gravity; moreover, the aforementioned mechanism is kept open by the force of magnetic attraction even against the typical tendentially closing force of a non-return ball valve, whose shutter ball - the second magnet 17 - is an embodiment thereof, against the sealing ring 27 to which the supply D of the pressurised water, during the flow of water, biases said shutter ball regardless of the arrangement of the valve body 5 or 32.

The safety valve 1 , as described earlier, has few movable parts: the slider 19 or 33, outside the valve body 5 or 32, and the second permanent magnet 16; they are housed at the end connected to the supply hose 11 parallel to the internal hose and to the external safety hose 8, coaxial to each other, which together form the supply hose 3. The overall dimensions of these parts outside the valve body turn out to be minimal, even as for the single movable part inside the valve body 5 or 32, i.e. , the shutter ball 17 - the second permanent magnet - which is inside the valve body 5 or 32 itself: for the actuation of the shutter ball 17 no further means are required, since the very strong magnetic attraction generated from the simultaneous presence of two permanent magnets attracting each other is sufficient. Finally, to ensure a strong attraction, both the first magnet 16 and the second magnet 17 - the shutter ball - are made of neodymium. For the sake of completeness, and considering the duration needed by the safety valve 1 , the shutter ball 17 is protected by a coating which prevents its oxidation, being constantly immersed in water, advantageously of the epoxy type.

The advantages in the use of an anti-flooding duct with safety valve for supplying water described herein are manifest, considering that the anti- flooding duct described earlier does not have sections other than the external radial size of the safety hose 8, even in the position for inserting the safety valve 1 , therefore the supply hose 3, considered as a whole, does not have impediments in the assembly, or cumbersome overall dimensions, i.e. , it proves to have minimum space requirement.

The arrangement of the safety valve 1 and its constitution make it insensitive to impacts and shaking, as described earlier, and finally the control mechanism for opening the safety valve 1 is insensitive to the position with respect to the force of gravity and is made so as to oppose the closing thrust, well known in the non-return ball valves, which insists on the shutter ball 17 - the second magnet - so as to ensure the constant opening of the valve except in the event of a flood in the interstice 26 formed between the two coaxial hoses: the internal hose and the external safety hose 8.

Obviously, a person skilled in the art, in order to satisfy specific and contingent requirements, may make numerous modifications to an anti- flooding duct with safety valve for supplying water, as previously described, all nevertheless falling within the scope of protection of the present invention as defined by the following claims.

Although less conveniently, the member sensitive to the flooding of the external safety hose 8 can be reduced to a single sponge, both of the yielding 22 type and of the swellable 21 type, possibly countered by a spring which defines the required thrust on the slider 19 or 33. The thrust required when adopting only a yielding sponge 22 uses the spring as a propulsive force in the sliding action of the slider upon the intervention of the water flow block; on the contrary, the thrust required when adopting only a swellable sponge 21 uses the spring as a force for positioning the slider and, therefore, the shutter ball 17 - the second magnet - for keeping the safety valve 1 open.

A possible assembly of a slider only with a yielding sponge must be carried out at the factory by suitably loading the spring, which replaces the swellable sponge, to compress the sponge that yields to flooding; alternatively, a slider only with a swellable sponge must be made at the factory by suitably loading the spring which replaces the yielding sponge to support the hydraulic thrusts on the shutter body, transmitted by magnetic action to the slider, before flooding: upon flooding, the swellable sponge will compress the spring and move the slider to the closing position.

In a simplified and less advantageous variant, it occurs with a possible assembly with only a yielding sponge 22, without the opposition of a spring, and wherein the first permanent magnet 16 has a suitable magnetic field to avoid the hydraulic dragging action due to the flow of water and closing of the non- return valve, constituting the safety valve 1 , which is possible even without the thrust spring which replaces the swellable sponge and with a ferromagnetic shutter body.

Furthermore, the first permanent magnet 16 may be made slidable laterally with respect to the duct and to its first part 13 without using a slider, as described, but in any way guided parallel to the duct of the valve body and subject to the yielding of a yielding sponge 22 or to the thrust of a swellable sponge 21.

Finally, the shutter ball 17 - the second magnet - can also be made of a ferrous and, therefore, not magnetized material, so as to exploit only one magnetic field generated by the first permanent magnet 16 housed, fixedly on the slidable slider 19 or 33, outside the valve body 5 or 32. Moreover, the shutter ball can be replaced by a non-spherical shutter made of a ferromagnetic material, but still guided within the first part 13 of the duct 12 of the valve body by the magnetic interaction of the first permanent magnet.

Claims

1. Anti-flooding duct with safety valve for supplying water, comprising an internal pressurised water intake hose; an external safety hose (8) coaxial to the internal hose for the entire length of this internal hose from the safety valve connected to the water distribution hose (11 ) to the outlet end (7) and watertight with respect to the external environment; characterized in that amidst the connection point of the water distribution hose (11 ), a valve body (5, 32) of the safety valve (1 ) comprises a permanent magnet (16) which is slidable outside the valve body in a direction parallel to the duct (12) of the valve body, i.e. , parallel to the sliding axis (C) of a shutter body made of a ferromagnetic material and slidable within a first part (13) of the duct (12); the shutter body is positioned with the magnetic interaction in the said first part; the opening position of the safety valve (1 ) is made by factory default and maintained by a member which is sensitive to the flooding of the external safety hose (8) which includes at least one water- sensitive sponge (21 , 22) to undoubtedly define said opening position of the safety valve (1 ), using the magnetic action of the permanent magnet (16), acting on the shutter body, and kept away by a sealing ring (27) inserted at the end of said first part (13) of the duct (12) inside the valve body (5, 32); the valve body being made of a non-ferromagnetic material; the coaxial space between said internal intake hose and the external safety hose (8) is in hydraulic connection with an interstice (26) for housing the said sponge.

2. Anti-flooding duct with safety valve, according to claim 1 , wherein the permanent magnet - the first magnet (16) - is housed in a slider (19, 33) lateral with respect to the valve body (5, 32) and made slidable thereon using guiding means (29, 30; 34) connected to the valve body.

3. Anti-flooding duct with safety valve, according to claim 1 or 2, wherein at least one yielding sponge (22) is inserted between the first permanent magnet and a second fixed abutment (25) of the valve body to counter at least the hydraulic thrust of the water flowing within the valve body before flooding.

4. Anti-flooding duct with safety valve, according to claim 1 or 2, wherein at least one swellable sponge (21 ) is inserted between the first permanent magnet and a first fixed abutment (24) of the valve body, to overcome, upon flooding, the resistances to the parallel sliding of the first magnet with respect to the valve body.

5. Anti-flooding duct with safety valve, according to claim 2, 3 or 4, wherein the first permanent magnet (16) is housed within a seat (20) in the slider which is provided with a partition abutment (23) for contacting the said yielding (22) and/or swellable (21 ) water-sensitive sponge.

6. Anti-flooding duct with safety valve, according to one of the preceding claims, wherein the shutter body is comprised of a shutter ball (17).

7. Anti-flooding duct with safety valve, according to one of the preceding claims, wherein the shutter body or the shutter ball (17) is made with a permanent magnet, the second magnet.

8. Anti-flooding duct with safety valve, according to claim 7, wherein one or both of the permanent magnets - the first and/or second magnets - is/are made of neodymium.

9. Anti-flooding duct with safety valve wherein the shutter body or shutter ball is made according to one of the preceding claims and has a protective coating against oxidation.

10. Anti-flooding duct with safety valve, according to one of claims 1 to 8, wherein the radial overall dimensions of the valve body (5, 32), determined by the half-shells (9) closing it, are equal to or slightly greater than the outer diameter of the external safety hose (8).