Patent Description:
Static type gas meters which do not have moving parts are known and widespread today. Such known gas meters generally comprise:.

The detection module includes, inside, one or more sensors able to detect one or more quantities useful for direct or indirect measurement, or by processing the detected data, of the gas flow. Conveniently, a communication module is also provided for transmitting the detected data, preferably via wireless, to an electronic control unit located outside the measurement unit.

Nowadays, in the gas meters sector the need is increasingly felt to have solutions in which the fouling of the sensor, or sensors, which operate inside the flow detection module, is reduced to a minimum and preferably eliminated, in order to keep the detection error curve within the limits required by the regulations in force throughout the life of the meter.

Gas meters are known today which, in order to retain the dust contained in the gas flow coming from the network, are provided with filtration means which are generally based on the principle of static electricity and / or on the principle of mechanical retention.

In these filtration media, the dust contained in the gas is retained by a cloth, before the gas flow enters the detection module in which the measurement is carried out.

However, this solution has an intrinsic limitation. In fact, once the upper layer of the cloth has been completely saturated with powders, dust retention is no longer guaranteed.

In these known filtration means, the path of the gas entering the gas meter provides that the gas flow enters from an inlet fitting, is deflected by <NUM>° and breaks against a flow diverter barrier, consisting of a cloth which traps the debris contained in the gas; meanwhile, the larger and heavier particles settle on the bottom of the box-like body of the gas meter, while the main gas flow, consisting of the lighter particles, is diverted in such a way as to leave the diverter barrier through a passage between it and the bottom of the box-like body of the gas meter, to then enter the controlled volume of the detection module.

When the diverter barrier cloth is no longer able to retain the dust suspended in the gas flow, these dust remain in the gas flow, thus dirtying the detection module which, inside the box-like body, is placed at downstream of the filtration media.

Furthermore, the gas flow, diverted so as to flow through a passage so as to lick the bottom of the box-shaped body, risks carrying with it part of the heavier particles which have deposited by gravity on the bottom of the box-shaped body.

Another limitation of known gas meters is constituted by the fact that the shut-off valve, generally defined by a solenoid valve, if present, is often positioned in correspondence with the meter inlet; in this position the solenoid valve is therefore subject to the flow of dust contained in the gas coming from the network.

Before the valve there may be a mechanical filter, for example of the metal mesh type, configured to retain the powders of larger dimensions but, once this filter is saturated, even partially, the finer powders still descend by gravity to the inside the solenoid valve, jeopardizing its long-term operation.

Furthermore, as the filter becomes saturated, its resistance to the flow of gas increases and, consequently, the pressure difference between the distribution network upstream of the meter and the outlet of the same increases, with consequent undesired modification of the fluid dynamic conditions inside the gas meter.

Furthermore, the powders are not collected in a limited volume and are continuously invested by the main gas flow before it enters the solenoid valve which, therefore, ends up collecting the majority of it.

The need is also increasingly felt in the sector to make gas meters safe against tampering attempts.

In particular, gas meters are known today which comprise a box-like body having an inlet and an outlet, both facing upwards with respect to a normal use of the gas meter. More in detail, generally, inside the box-shaped body there may be present - in the order in which the gas flow is crossed - a mechanical filter, in correspondence with the inlet, a flow shut-off solenoid valve and a detection module one or more parameters for determining the gas flow rate.

In such known gas meters, the detection module is mechanically and fluidically connected directly to the outlet fitting and is arranged contiguously with this outlet fitting. This mounting position of the measuring module inside the box-like body lends itself to easy tampering with the detection module, since it is not currently required by the standards that the outlet fitting is sealed. Even in the presence of a protective mesh filter between the detection module and the outlet fitting, this solution does not appear effective in the event of tampering attempts such as for example the release of the detection module, the obfuscation of one or more sensors present. in the detection module, the damage of the latter with compressed air, and the like.

<CIT> discloses a gas meter comprising a containment body with a mouth for the entry of the gas inside the containment body and a mouth for the exit of the gas from the containment body; inside the containment body there are housed a measuring device suitable for detecting one or more parameters for determining the gas flow rate, and a filter suitable for filtering the gas flow. In particular, the filter comprises a chamber for depositing the dust present in the incoming gas, and in which the dust depositing chamber is in communication with the inlet port of the containment body and comprises a dust collection base and a wall filter outlet equipped with through openings.

The object of the invention is to propose a gas meter which allows to overcome, at least in part, the drawbacks and limitations of traditional solutions.

Another object of the invention is to propose a gas meter in which various types of detection modules can be used, even those already available on the market, and this without compromising the metrological performance of the meter itself over time.

Another object of the invention is to propose a gas meter which effectively separates the dust contained in the gas before they enter the detection module and / or the shut-off valve housed inside the meter.

Another object of the invention is to propose a gas meter in which the detection module and the shut-off valve are more protected from the dust contained in the mains gas which enters the meter itself.

Another object of the invention is to propose a gas meter that is safer with respect to the risks of tampering.

Another object of the invention is to propose a gas meter with a performance that is not inferior to known gas meters.

Another object of the invention is to propose a gas meter which is easy and quick to maintain, as well as inexpensive.

Another object of the invention is to propose a gas meter which can be obtained simply, quickly and with low costs.

Another object of the invention is to propose a gas meter which is in line with the regulations in force in the sector.

Another object of the invention is to propose a gas meter which allows a precise and reliable measurement, even over time, of the gas that passes through it.

Another object of the invention is to propose a gas meter which is highly safe and reliable.

Another object of the invention is to propose a gas meter which is an improvement and / or alternative to the traditional ones.

Another object of the invention is to propose a gas meter which presents an alternative characterization, both in constructive and functional terms, with respect to the traditional ones.

The gas meter according to the invention is defined in appended independent claim <NUM>.

The present invention is further clarified hereinafter in some of its preferred embodiments reported for purely illustrative and non-limiting purposes with reference to the attached drawings, in which:.

With reference to the cited figures, the present invention relates to a gas meter which is indicated as a whole with the number <NUM>.

Conveniently, the inlet <NUM> and outlet <NUM> are obtained on the containment casing <NUM>.

Conveniently, the containment casing <NUM> is watertight to prevent the escape of gas to the outside. Preferably, the containment casing <NUM> is formed by two or more parts <NUM>' and <NUM>" joined together so as to ensure the hermetic sealing of the entire envelope. Preferably, the containment casing <NUM> is made of metal, in particular of metal sheet.

Inside the containment casing <NUM> of the meter <NUM> there is a module <NUM> for detecting one or more parameters of the gas, in particular for detecting one or more parameters for determining the flow rate of the gas that enters / passes through the meter.

Conveniently, inside the containment casing <NUM> of the meter <NUM> there is also housed an shut-off valve <NUM> of the gas flow that passes through the meter <NUM>. Preferably, the shut-off valve <NUM> is a solenoid valve. Preferably, as shown in the figures, the shut-off valve <NUM> is positioned in correspondence with the outlet port <NUM>. Conveniently, the shut-off valve <NUM> is mounted at the inlet and / or outlet and / or is crossed by an outlet duct.

Conveniently, the gas meter <NUM> comprises, at its inlet <NUM>, an inlet fitting <NUM>. Conveniently, the inlet fitting <NUM> is fixed (if it is made in a separate piece) and / or integrated (if it is made in a single piece with the corresponding part <NUM>' ) to the casing <NUM> in correspondence with the inlet <NUM> of the casing itself. Preferably, in a possible embodiment, the inlet fitting <NUM> is provided with an externally threaded portion to thus allow its screwing into a corresponding internal thread provided at the inlet <NUM> of the containment casing <NUM>.

Conveniently, the gas meter <NUM> comprises, at its outlet <NUM>, an outlet fitting <NUM>. Conveniently, the outlet fitting <NUM> is fixed (if it is made in a separate piece) and / or integrated (if it is made in a separate piece) single piece with the corresponding part <NUM>' ) to the casing <NUM> at the outlet <NUM> of the casing itself. Preferably, the outlet fitting <NUM> is provided with an externally threaded portion to thus allow its screwing into a corresponding internal thread provided at the outlet port <NUM> of the containment casing <NUM>.

Conveniently, inside the containment casing <NUM> of the meter <NUM> also houses filtration means <NUM> for the flow of gas.

The meter <NUM> comprises a first zone <NUM> and a second zone <NUM> which are entirely defined inside the containment casing <NUM>. Conveniently, the flow of gas entering the meter <NUM> first passes through the first zone <NUM> and subsequently the second zone <NUM> and therefore, considering the gas flow inside the meter, the second zone <NUM> is defined downstream with respect to the first zone <NUM>.

Conveniently, the first zone <NUM> and the second zone <NUM> are defined inside the containment casing <NUM> so that:.

and in such a way that the fluidic connection between said first zone <NUM> and said second zone <NUM> occurs exclusively through a passage <NUM> comprising filtration means <NUM>.

Conveniently, inside'containment casing <NUM> separation means are provided which separate the first zone <NUM> and the second zone <NUM> from each other.

Conveniently, in a possible embodiment (see <FIG>), the separation means may comprise a separation structure <NUM> with a protruding body <NUM>, box-shaped, and with a frame <NUM> which is configured to mechanically engage in mod or removable, preferably by interlocking or snapping, on the protruding body <NUM>.

Conveniently, the filtration means <NUM> comprise at least one filter element <NUM> which is mounted on said separation means which separate the first zone <NUM> and the second zone <NUM>.

Conveniently, said at least one filter element <NUM> is mounted on said separation means and is made of a different material than that with which said separation means are made.

Conveniently, the separation means comprise at least two mounting elements - for example defined by the separation element <NUM> with the lower frame <NUM>, or by the protruding body <NUM> with the frame <NUM> - which are configured to be mechanically constrained to each other in a removable way. Furthermore, said filter element <NUM> is a filter mat which is positioned and / or retained, preferably in a removable way, between said at least two mounting elements - for example defined by the separation element <NUM> and the lower frame <NUM>, or by the frame <NUM> and from the protruding body <NUM> - when they are mechanically linked together.

Preferably, in a possible embodiment, the entire internal volume of the containment casing <NUM> is divided into a first zone <NUM> and a second zone <NUM> by a separation element <NUM> on which filtration means <NUM> are mounted and / or obtained.

Preferably, the separation element <NUM> is interposed between two opposite walls <NUM> and <NUM> of the containment casing <NUM>. Preferably, the first zone <NUM> and the second zone <NUM> are superimposed and are separated from each other by an separation element <NUM> on which at least one filter element <NUM> is mounted. More in detail, the first zone <NUM> can be delimited by the separation element <NUM>, by the bottom wall <NUM> of the casing <NUM> and by the side walls of the containment casing <NUM> defined between the separation element <NUM> and the bottom wall <NUM> of the casing; the second zone <NUM> can be delimited by the separation element <NUM>, by the upper wall <NUM> (ie the opposite wall with respect to the bottom one <NUM>) of the casing <NUM> and by the side walls of the containment casing <NUM> defined between the separation element <NUM> and the upper wall of the casing <NUM>.

Conveniently, the separation element <NUM> can be mounted and / or supported at the junction area between the two parts <NUM>' and <NUM>" which, once mutually joined at the flanged edges, define the containment casing <NUM>. Preferably, the separation element <NUM> is mounted by means of sealing means (such as for example a sealing substance and / or a gasket) at the junction area <NUM> between the two parts <NUM>' and <NUM>" which define the containment casing <NUM>.

Conveniently, the two parts <NUM>' and <NUM>" define two shells of different height but configured to be in contact with each other at the respective flanged edges <NUM>' and <NUM>". Conveniently, the flanged edges can be fixed to each other by welding and / or by means of an adhesive and / or by folding one over the other and / or by means of screws <NUM>. Conveniently, between the flanged edges <NUM>' and <NUM>", respectively of the parts <NUM>' and <NUM>", a gasket element <NUM> can be interposed.

Preferably, the inlet port <NUM> is formed on the upper wall <NUM> of the casing <NUM>.

Conveniently, it is understood that the inlet <NUM> and the outlet <NUM> can both be made on another same wall other than the upper wall <NUM>. It is to be understood that the inlet <NUM> and the outlet <NUM> can each be made on a respective wall of the containment casing <NUM>, different from the wall on which the other mouth is made.

Preferably, in a possible embodiment, the first zone <NUM> is defined inside the casing <NUM> on the opposite side to that in which the inlet <NUM> and / or outlet <NUM> are formed.

Conveniently, the first zone <NUM> is in fluid communication with the inlet fitting <NUM> by means of an inlet duct <NUM>. Conveniently, the inlet duct <NUM> passes through - at least in part - the second zone <NUM>.

The second zone <NUM> communicates with the first zone <NUM> only by means of at least one passage <NUM> comprising filtration means <NUM>. In particular, the first zone <NUM> is configured in such a way that the gas flow enters it only through the inlet duct <NUM> and from here exits towards the second zone <NUM> only through at least one passage <NUM> which is provided with filtration means <NUM>.

The inlet of the detection module <NUM> is in fluid communication with the second zone <NUM>. The detection module <NUM> and the shut-off valve <NUM> are housed inside the second zone <NUM>.

As mentioned, the gas meter <NUM> comprises an inlet duct <NUM> which is also housed entirely inside the casing <NUM>. Conveniently, the inlet duct <NUM> is configured to be fluidically sealed, preferably by means of the inlet fitting <NUM>, with a gas inlet duct (not shown) external to the meter <NUM>. Conveniently, the inlet duct <NUM> is configured to receive and be traversed by all the gas which is intended to enter inside the containment casing <NUM>.

In particular, the inlet duct <NUM> extends longitudinally along a direction X.

The inlet duct <NUM> is configured to pass through the inlet <NUM> and to fit tightly inside the inlet fitting <NUM>. In particular, the inlet duct <NUM> passes through the inlet port <NUM> and extends towards an opposite wall, ie the bottom wall <NUM>, of the containment casing <NUM>.

In particular, the inlet duct <NUM> comprises an inlet section <NUM> which fits tightly within the inlet fitting <NUM>. Conveniently, the inlet section <NUM> is configured to engage in shape relationship within the inlet fitting <NUM> Advantageously, moreover, on the external walls of the inlet section <NUM> there is mounted a gasket <NUM>, preferably an O-ring, which is intended to be compressed by the internal walls of the inlet fitting <NUM> when the inlet section <NUM> is inserted inside. of the fitting itself. Conveniently, for this purpose, a seat, for example a circumferential groove, and / or a circumferential flange, can be provided on the external walls of the inlet section <NUM> to keep the gasket <NUM> in position.

Advantageously, in correspondence with the inlet section <NUM>, the inlet duct <NUM> can be provided, underneath the gasket <NUM>, with a flange <NUM> to ensure a block in the event of a possible release of the inlet duct from the inlet fitting <NUM> and, moreover, it advantageously acts as a reference for the assembly of the inlet duct in the inlet fitting <NUM> to prevent the first from entering too much inside the second.

The inlet duct <NUM> also comprises an outlet section <NUM> - which is opposite to the inlet section <NUM> - which enters the first zone <NUM> through a hole 26a defined on a separation element <NUM> which divides the first zone <NUM> from the second zone <NUM>. Conveniently, the outlet section <NUM> protrudes, at least in part, inside the first zone <NUM>.

Conveniently, the inlet section <NUM> and the outlet section <NUM> are defined at two opposite ends of the inlet duct <NUM>, in particular of two ends which are opposite each other along the longitudinal extension X of the inlet duct <NUM>.

Therefore, suitably, the inlet duct <NUM> is in fluidic connection, in correspondence with its inlet section <NUM>, with the inlet of the gas inside the meter <NUM> and, in correspondence with its outlet section <NUM>, is in direct or indirect communication (ie through a further chamber <NUM>, as described below). with the first zone <NUM>.

Conveniently, the inlet duct <NUM> comprises an elongated body which is internally hollow to thus allow the gas to pass through. Preferably, the inlet duct <NUM> is made in a single piece. Conveniently, the inlet duct <NUM> is made of polymeric material, preferably by molding.

Conveniently, the inlet duct <NUM> has a cross section that varies in terms of shape and size along its longitudinal extension X, in particular the cross section provided at the inlet section <NUM> is different from that of the central section and / or of the outlet section <NUM> of the duct itself.

Conveniently, the cross section of the inlet section <NUM> of the inlet duct <NUM> is circular or substantially circular.

Conveniently, the cross section of the outlet section <NUM> of the inlet duct <NUM> is semicircular or substantially semi-circular (for example, slightly elongated semicircular).

In a possible embodiment, the cross section of the inlet section <NUM> of the inlet duct <NUM> can define a passage area greater than that of the cross section of the outlet section <NUM> of the duct itself.

Conveniently, in another possible embodiment, the section of the inlet section <NUM> of the inlet duct <NUM> can define a passage area that is smaller than that of the section of the outlet section <NUM> of the duct itself. Advantageously, the inlet duct <NUM> can have a substantially flared longitudinal development that goes from the inlet section <NUM> towards the outlet section <NUM>.

Conveniently, mechanical engagement means, preferably snap-fit or snap-fit, are provided in correspondence with the outlet section <NUM>, with the edges of the hole 26a of a separation element <NUM> which, in fact, separates the first zone <NUM> and the second zone <NUM> from each other defined inside the containment casing <NUM>.

The inlet duct <NUM> comprises inside at least one gas passage channel <NUM> with at least one bottom <NUM> which is closed / blind so that the dust of the gas entering said channel is deposited on the bottom <NUM> of said channel. Conveniently, the outlet of the channel <NUM> faces or is angled / lateral with respect to the bottom <NUM> so that the outgoing gas flow is diverted from the bottom itself.

Preferably, each channel <NUM> defined inside the inlet duct <NUM> is configured so that the gas flow exiting the channel is deviated from the bottom <NUM> of the channel itself by an angle equal to or less than about <NUM>°, with respect to the direction of the flow. of incoming gas, to thus generate a movement of the gas flow in countercurrent inside the duct itself.

Conveniently, the longitudinal development direction of the channel <NUM> is substantially corresponding to / parallel to the longitudinal development direction X of the inlet duct <NUM> and, therefore, the gas flow entering and passing through the channel <NUM> is parallel to the gas flow entering and passes through the remaining part of the inlet duct <NUM>.

Conveniently, the inlet duct <NUM> comprises inside at least one dividing element <NUM>, preferably a wall, to thus laterally delimit, at least in part, the channel <NUM>. Preferably, the dividing element <NUM> of each channel <NUM> is integrated with external walls <NUM> in the inlet duct <NUM> and are molded in a single piece. Preferably, the dividing elements <NUM> are defined by extension walls which develop substantially parallel to the longitudinal development direction of the inlet duct <NUM>.

Preferably, the bottom <NUM> of each channel <NUM> is defined by a solid base (ie without openings or through holes ) which is arranged angled inside the inlet duct <NUM>, ie defines an angle of about <NUM>-<NUM>° with respect to the longitudinal development direction X of the inlet duct <NUM>. Preferably, the bottom <NUM> of each channel <NUM> is integrated with the external walls <NUM> of the inlet duct <NUM> and are molded in one piece. Preferably, the bottom <NUM> can be defined by recesses in the external walls <NUM> of the inlet duct <NUM> and / or by transverse extensions of the dividing elements <NUM>.

Conveniently, in a possible embodiment (see Fig. 9c), the channel <NUM> comprises inside it one or more shoulders <NUM> placed at a lower depth / height than the bottom <NUM> of the same channel.

Preferably, the dividing element <NUM> and the bottom <NUM> of each channel <NUM> are integrated with the external walls <NUM> of the inlet duct <NUM> and are molded in a single piece.

Conveniently, at least one channel <NUM> can be delimited below by the bottom <NUM> and laterally by the dividing element <NUM> and also by the external walls <NUM> of the inlet duct <NUM>. Conveniently, in a possible variant embodiment, at least one channel <NUM> can be delimited below by the bottom <NUM> and laterally only by a dividing element <NUM>.

Preferably, the opening <NUM> for the gas inlet into the channel <NUM> (hereinafter defined as "inlet opening <NUM>") faces the bottom <NUM>.

Conveniently, in a possible form of embodiment, the opening <NUM> for the gas outlet from channel <NUM> (hereinafter defined as "outlet opening <NUM>") is also facing or aligned with the bottom <NUM> and, preferably, coincides with the inlet opening <NUM>.

Conveniently, in a possible embodiment, the outlet opening <NUM> is made on a side wall that delimits the channel <NUM>. Preferably, the outlet opening <NUM> is positioned along the longitudinal development of the channel <NUM>, between the inlet opening <NUM> and the bottom <NUM>.

Advantageously, in a possible embodiment (cf. <FIG>, <FIG>), a single dust deposit channel <NUM> can be provided inside the inlet duct <NUM>. Preferably, the dust deposit channel <NUM> is defined in correspondence with the inlet section <NUM> and, in particular, the inlet opening <NUM> of the channel <NUM> is defined in correspondence with the inlet end of the duct <NUM>. Conveniently, the outlet opening <NUM> of channel <NUM> coincides with the inlet opening <NUM> of the channel itself. More in detail, in this embodiment, a dividing element <NUM> is provided in correspondence with the inlet section <NUM> which thus divides the lumen of the inlet section <NUM> into a dust deposit channel <NUM> and into a further passage <NUM>. Preferably, the The dividing element <NUM> is a wall which extends along the diameter of the inlet section <NUM> of the inlet duct <NUM>.

Therefore, the flow of gas entering the inlet duct <NUM> conveniently enters partly into the dust deposit channel <NUM> and into part enters directly / immediately in the further passage <NUM>. Therefore, the dust present in the part of the gas flow entering the channel <NUM> accumulates on the bottom <NUM> of the channel itself and, furthermore, the trajectory of the gas flow entering the channel <NUM> is deflected - preferably substantially <NUM>° - towards the inlet end of the inlet duct <NUM>, to then re-enter the further passage <NUM>.

Conveniently, said further passage <NUM> can define a straight and free path (i.e. without further deviations) towards the outlet section <NUM> (cf. <FIG>, <FIG> and <FIG>, <FIG> and <NUM>) or said further passage <NUM> can define a further channel <NUM> for depositing the powders (see <FIG>). More in detail, in the latter case, the dust present in the part of the gas flow entering said further channel <NUM> accumulates on the corresponding bottom <NUM> of the channel itself and, moreover, the trajectory of the gas flow entering the channel <NUM> is diverted towards the outlet opening <NUM> which is formed laterally with respect to the bottom <NUM>, to thus enter an area of the inlet duct <NUM> which is then in fluid communication (direct or through a powder deposit chamber <NUM>) with the first zone <NUM>.

Advantageously, therefore, in a possible embodiment, two or more dust deposit channels <NUM> can be defined inside the inlet duct <NUM>. Conveniently, the dust deposit channels <NUM> cause one or more deviations of the gas flow that passes through the inlet duct <NUM>, preferably thus forcing the gas flow - which is diverted from the blind / closed bottom <NUM> of each channel - to rise, at least in part, towards the direction of entry of the flow into the channel itself. Preferably, two or more dust deposit channels <NUM> can be provided inside the inlet duct <NUM> so that the flow of gas that crosses the duct crosses a path that is not linear and free, but has one or more bends and / or elbows.

In essence, therefore, the gas flow that crosses the inlet duct <NUM> enters - at least in part - inside the channel <NUM>, defined inside the duct itself and, advantageously, the dust present in the gas flow is deposited and thus accumulate by gravity on the closed / blind bottom <NUM>; moreover, the direction of the gas flow entering the channel <NUM>, defined inside the inlet duct <NUM>, is advantageously deviated from the closed / blind bottom <NUM>, thus causing an initial accumulation of the dust present in the gas flow, entering the meter <NUM>, in correspondence with an area which is far from / distanced from the measuring module <NUM>.

Conveniently, in the embodiment shown here, the outlet section <NUM> of the inlet duct <NUM> opens fluidically directly inside the first zone <NUM> and, therefore, the gas dusts are deposited on the bottom wall <NUM> of the containment casing <NUM>.

Advantageously, in a possible embodiment not shown here, the meter <NUM> also comprises a dust deposit chamber which is in fluidic communication with the inlet duct, in particular, is in fluid communication with the outlet section <NUM> of said duct. Conveniently, in one embodiment, the chamber is defined inside a cup-shaped body which is mechanically engaged, preferably by interlocking or snapping, to the outlet portion of the inlet duct <NUM>, preferably so as to hang from the duct same. Advantageously, the cup-shaped body can be configured so that the chamber is closed at the bottom while in correspondence with its side walls it has filtering means, preferably a plurality of through openings configured to obstruct the passage of the powder.

Advantageously, therefore, the flow of gas which exits from the inlet duct <NUM> in a substantially vertical direction from top to bottom, enters the chamber provided in the first zone <NUM> and there its trajectory is diverted from the bottom of the chamber itself, towards the filtration means <NUM>. Therefore, the flow of gas which then passes from the first zone <NUM> into the second zone <NUM> is forced to pass through the passages <NUM> comprising said filtration means <NUM>.

Therefore, the gas flow that reaches the second zone <NUM> and then enters the detection module <NUM> is suitably filtered and cleaned of dust. In fact, a first stage for the removal of dust from the incoming gas is envisaged through each channel <NUM> with blind / closed bottom <NUM> provided inside the inlet duct <NUM>, then a (possible) second deposition stage (by gravity) of the dust on the bottom of zone <NUM> or on the bottom of a dedicated chamber, and a further (third) stage of dust removal is also provided through the filtration means <NUM> provided / defined at the passages <NUM> between the first zone <NUM> and the second zone <NUM> which is in direct fluid communication with the detection module <NUM>.

A detection module <NUM> of one or more parameters is housed inside the containment casing <NUM>, preferably for determining the gas flow rate; also this detection module <NUM> has an inlet opening 19a and an outlet opening 19b.

A shut-off valve <NUM> for the flow of gas through the gas meter structure <NUM> can be housed inside the containment casing <NUM>; this shut-off valve <NUM> having an inlet opening 18a and an outlet opening 18b.

The gas meter <NUM> also comprises an outlet duct <NUM>, extending from the outlet <NUM> towards an opposite wall <NUM> of the containment casing <NUM>.

Advantageously, the detection module <NUM> is positioned inside the second zone <NUM> between the inlet duct <NUM> and the outlet duct <NUM>.

Advantageously, the shut-off valve <NUM> is mounted in correspondence with the outlet duct <NUM>.

As said, in correspondence with the passages <NUM> between the first zone <NUM> (which is fluidic communication with the inlet duct <NUM>) and the second zone <NUM> (which is in fluidic communication with the inlet of the detection module <NUM>) filtration means <NUM> are provided. Conveniently, in a possible embodiment, the filtration means <NUM> are mounted / associated with a separation element <NUM> between the first zone <NUM> and the second zone <NUM>.

In a possible and preferred embodiment, the separation element <NUM> is made of rigid plastic material, for example in polypropylene or similar materials.

Advantageously, the inlet duct <NUM>, with its outlet section <NUM>, passes through an hole 26a which is defined on the separation element <NUM>. Preferably, in correspondence with the outlet section <NUM>, the inlet duct <NUM> comprises a flange which is configured to abut the edges delimiting the hole 26a.

As mentioned, the first zone <NUM> is configured in such a way that the gas flow coming from the inlet duct can exit from said first zone <NUM> only by passing through the filtration means <NUM> mounted on the separation element <NUM>.

Conveniently, the meter <NUM> it also comprises a support element <NUM> on which the detection module <NUM> is mounted. Conveniently, the outlet duct <NUM>, on which the shut-off valve <NUM> is preferably mounted, is also mounted on the same support element <NUM> on which it is mounted the detection module <NUM>.

In the embodiment of the invention described here, by way of non-limiting example of the invention, the support element <NUM> comprises a base portion <NUM>, suitably shaped, which is positioned inside the containment casing element <NUM>.

Preferably, in a possible embodiment in which the support element <NUM> also defines the separation element <NUM> between the two zones <NUM> and <NUM> (cf. <FIG>), the base portion <NUM> is configured (in terms of shape and size) in imitation of the internal cross-sectional profile of the containment casing <NUM>, i.e. so that the perimeter edges of this base portion <NUM> are arranged in proximity to or in contact with the internal surface of the containment casing <NUM>.

Preferably, the base portion <NUM> comprises a perimeter flange <NUM> configured to be arranged and sealed at the junction area <NUM> between the two parts <NUM>' and <NUM>" which define the containment containment casing <NUM>. In particular, the perimeter flange <NUM> is intended to rest and / or be clamped between the corresponding flanged edges <NUM>' and <NUM>" of the parts <NUM>' and <NUM>" respectively of the containment casing <NUM>.

Advantageously, a tank <NUM> is also mounted on the base portion <NUM>. Preferably, the base portion <NUM> is constituted by a single piece of rigid plastic material and the tank <NUM> is also constituted by ta from a single piece of rigid plastic material. Preferably, the edges of the tank <NUM> are sealed together, for example by thermal welding, or with other similar and equivalent sealing joining methods, to the base portion <NUM>. Conveniently, the tank <NUM> is housed inside the first zone <NUM> while being fluidly separated from the latter.

Preferably, the base portion <NUM> and the tank <NUM> are made of rigid plastic material, for example of polypropylene or similar materials.

Conveniently, in a possible and preferred embodiment, the support element <NUM> is defined by and within the separation element <NUM> (see <FIG>). Preferably, in this case, the base portion <NUM> comprises the support element <NUM> for mounting the detection module <NUM> and the outlet duct <NUM> and also, again on the base portion <NUM>, the hole 26a is formed within the which engages the outlet section <NUM> of the inlet duct <NUM> and, moreover, comprises the filtration means <NUM> which are defined by a filter element <NUM> which is associated with the separation element itself. Conveniently, therefore, in this case, the detection module <NUM> is mounted on the separation element <NUM>. Conveniently, the outlet duct <NUM> with the shut-off valve <NUM> is also mounted on the separation element.

In another possible embodiment (see fig. <NUM>-<NUM>), in which said separation element <NUM> is not provided between the two zones <NUM> and <NUM>, the support element <NUM> is defined by a dedicated element which it only acts as a support for said detection module <NUM> and for the outlet duct <NUM>.

Conveniently, the detection module <NUM> is connected tightly to the support element <NUM> and also the outlet duct <NUM> is connected tightly to the same support element <NUM>.

As mentioned, the detection module <NUM> and the outlet duct <NUM>, on which the shut-off valve <NUM> is preferably mounted, are conveniently placed side by side and parallel to each other.

Inside the containment casing <NUM> there are means <NUM> configured for the deviation of the flow of gas exiting from the outlet opening 19b of the detection module <NUM> towards the inlet opening 40a of the outlet duct <NUM>.

Conveniently , the means <NUM> for diverting the flow comprise a tank <NUM> configured to define a "U" curvature of the gas flow leaving the detection module <NUM> to make it enter the outlet duct <NUM>.

Advantageously, the tank <NUM> also defines a tank for the collection of any powders which have passed through the detection module and which thus settle on the bottom of the tank <NUM>.

Conveniently, the tank <NUM> is associated with the support element <NUM> and, in particular, is tightly fixed to the support element <NUM> in correspondence with the face of the latter which is opposite to that in correspondence with which the detection module <NUM> and the outlet duct are connected. Advantageously, therefore, the detection module <NUM>, the support element <NUM>, the tank <NUM>, the outlet duct <NUM> - on which the shut-off valve <NUM> is preferably mounted - define a gas-tight unit which is fluidically inlet connected with the second zone <NUM> defined inside the casing <NUM> and at the outlet it is fluidically connected with an outlet pipe to the meter <NUM>. Preferably, the terminal portion <NUM> of the outlet duct <NUM> is sealedly connected with the outlet port <NUM>.

Conveniently, the terminal portion <NUM> of the outlet duct <NUM> is configured to engage in a proportional relationship within the outlet fitting <NUM>. Advantageously, moreover, a gasket <NUM>, preferably an O-ring, is mounted on the outer walls of the terminal portion <NUM>, which is intended to be compressed by the internal walls of the outlet fitting <NUM> when the terminal portion <NUM> is inserted inside the fitting itself. Conveniently, for this purpose, a seat, for example a circumferential groove, and / or a circumferential flange, can be provided on the outer walls of the terminal portion <NUM> to keep the gasket <NUM> in position.

Conveniently, another gasket <NUM>, preferably an O-ring, is also mounted on the outlet duct <NUM>, for the sealing connection with the inlet portion 40b.

In more detail, moreover, the support element <NUM> comprises:.

Both the junction collar <NUM> and the inlet portion 40b are open and in fluid communication with the tank <NUM>.

As mentioned, inside the containment casing <NUM> are means <NUM> are present configured for the deviation - preferably by an angle of <NUM>° -<NUM>° and, even more preferably, by an angle of approximately <NUM>° - of the gas flow leaving the outlet opening 19b of the detection module <NUM> towards the inlet 40a of the outlet duct <NUM>.

Advantageously, the detection module <NUM> is positioned, as mentioned above, in the middle between the outlet duct <NUM> and the inlet duct <NUM>, flanked both by the outlet duct <NUM> than to the inlet duct <NUM>. In this intermediate position, and thanks to the means <NUM> for diverting the gas flow out of the outlet opening 19b of the detection module <NUM> towards the inlet opening of the outlet duct <NUM>, the detection module <NUM> is substantially unreachable from any attempt at tampering that is carried out either through the outlet <NUM>, or possibly through the inlet <NUM> of the containment casing <NUM>. In fact, the presence on one side of the inlet duct <NUM> and of the separation element <NUM>, on the other side of the shut-off valve <NUM> and of the flow diversion means <NUM>, causes the detection module <NUM> to be substantially placed in the center of a labyrinthine path that cannot be traveled with the burglary instruments known today.

The detection module <NUM> is, for example, a static type flow detector. Preferably, the detection module <NUM> is of the ultrasonic type. Conveniently, the detection module <NUM> can be thermomassic.

This detection module <NUM> comprises a transit tube <NUM> for the flow of gas, of which the inlet 19a and outlet 19b openings are part, and inside which the actual sensors are present.

In a variant embodiment of the invention, the detection module <NUM> comprises an electronic unit <NUM> external to the transit tube <NUM>. Conveniently, the electronic unit <NUM> is configured to power and control the sensors, to perform the reception of the detection signals emitted. from sensors and for the transmission of signals and / or data to an external control unit.

Conveniently, the longitudinal development direction of the transit tube <NUM> and of the outlet duct <NUM> are substantially parallel to the longitudinal development direction X of the inlet duct <NUM>. Preferably, the detection module <NUM> is positioned with the inlet opening 19a which is in direct fluidic communication with the second zone <NUM> and which is located near the upper wall <NUM> of the containment casing <NUM>.

Advantageously, the detection module <NUM> is positioned so that its electronic unit <NUM> is arranged beyond above the filter element <NUM>; in this way, thanks to the specific position of the filter element <NUM> placed, on said flat portion, between the inlet hole 26a and the junction collar <NUM> for the connection of the detection module <NUM>, the casing of the electronic unit <NUM> cooperates in the deviation of the gas flow and therefore in the filtration of the gas flow, since this casing of the electronic interface unit accumulates on its surface any residual dust present in the gas flow.

Conveniently, the separation element <NUM> is interposed between the bottom wall <NUM> and the inlet opening 19a of the detection module <NUM>.

In the form of the invention described here, by way of non-limiting example of the invention itself, the means <NUM>, configured for the deviation of the gas flow exiting from the outlet opening 19b of the detection module <NUM> towards the inlet opening 40a of the outlet duct <NUM>, comprise the base portion <NUM> inside which a diversion chamber <NUM>.

The detection module <NUM>, the means <NUM> for deviating the gas flow and the outlet duct <NUM>, in correspondence with which the shut-off valve <NUM> is preferably mounted, are connected together so as to define a sealed path configured to prevent the gas flow already counted by the detection module <NUM> from escaping. Conveniently, the outlet opening 19b of the detection module <NUM> and the junction collar <NUM> of the base portion body <NUM> are tightly connected. Conveniently, the inlet portion 40b and the inlet of the shut-off valve <NUM> are connected tightly. Conveniently, the outlet of the shut-off valve <NUM> is sealedly connected to the outlet duct <NUM> which is then sealedly connected to the outlet fitting <NUM>.

In a possible variant embodiment not shown, the shut-off valve <NUM> is not present or it could be mounted upstream of the inlet duct <NUM>.

The filtration means <NUM> provided in correspondence with said at least one passage <NUM> between the first zone <NUM> and the second zone <NUM> are defined by a filter element <NUM> which is made of a different material compared to that with which the separation element <NUM> is made.

Conveniently, the filter element <NUM> defines a substantially flat or at most slightly curved filtering wall / septum, delimiting said first zone <NUM> and said second zone <NUM>.

Preferably, the casing <NUM> internally comprises an intermediate chamber, fluidically interposed between the first zone <NUM> and the second zone <NUM>, and in which it is housed - preferably to measure - the filter element <NUM>. In accordance with the embodiment illustrated in the attached <FIG>, the intermediate chamber is defined by the separation element <NUM> and the lower frame <NUM>, when they are mechanically connected to each other in a removable way. In accordance with the embodiment illustrated in the attached <FIG>, the intermediate chamber is defined inside the separation structure <NUM> and is defined by the frame <NUM> with the protruding body <NUM>, when they are mechanically constrained to each other in a removable way. Advantageously, the filter element <NUM> housed in the intermediate chamber which mechanically and fluidically separates the first zone <NUM> from the second zone <NUM>. Advantageously, moreover, the intermediate chamber houses the filter element <NUM> to size, preventing deformation of the latter as the temperature varies. pressure of the gas passing through it.

Conveniently, the filter element <NUM> is mounted so that the first zone <NUM> and the second zone <NUM> are separated from each other by and / or along the thickness S of the filter element itself.

Conveniently, the filter element <NUM> is a filter mat. Conveniently, the filter element <NUM> is shaped like a filter mat. Conveniently, the filter element is not of the pocket type, and in particular it is not shaped like a bag, envelope or bag with an open end.

Conveniently, each filter element <NUM> has a configuration in which the development along the thickness S is lower - in particular much lower - than that in the other two dimensions that define the surface extension of the filter. Conveniently, the shape and dimensions of the surface extension of the filter element <NUM> correspond and / or are slightly oversized with respect to the corresponding section of the passage <NUM> to be covered.

Conveniently, each filter element <NUM> has a stable and well-defined three-dimensional shape. Preferably, the filter element <NUM> is configured to have a surface extension that is flat or substantially flat.

Preferably, the filter element <NUM> is housed / positioned entirely, or in any case for the most part, inside - and in particular within the overall dimensions - of the separation means - for example defined by the separation element <NUM> with the lower frame <NUM>, or from the protruding body <NUM> with the frame <NUM> - on which the filter element <NUM> is mounted, thus optimizing its overall dimensions inside the casing <NUM>.

Conveniently, each filter element <NUM> is configured so as to have a surface extension which is substantially flat and which is substantially coplanar or parallel, for its entire surface development, to the cross section of said at least one passage <NUM> in correspondence with which the filter element itself is installed.

Conveniently, each filter element <NUM> is configured and / or mounted in such a way as to have a thickness S which remains substantially constant along its entire surface extension.

Conveniently, each filter element <NUM> is configured and mounted so as to be and remain coplanar for its entire surface development.

Conveniently, in a possible embodiment (see <FIG>), the interior of the casing <NUM> is divided by the separation element <NUM> into a first zone <NUM> which is in fluid communication with the inlet duct <NUM> and in a second zone <NUM> which is in fluid communication with the detection module <NUM>. The two zones <NUM> and <NUM> are in fluid communication with each other only in correspondence with one or more passages <NUM> which are completely covered and affected by a filter element <NUM> which is made of a material different from that of which said separation.

Preferably, the separation element <NUM> is made of rigid polymeric material, preferably polypropylene.

Conveniently, the filter element <NUM> is made of a fabric of polymeric fibers, preferably of a non-woven fabric of polymeric fibers, for example of heat-sealed elastic polyolefin fibers.

Preferably, the filter element <NUM> has a density of the fiber layers which increases from the inlet surface towards the outlet surface.

Preferably, the filter element <NUM> has a thickness S of about <NUM> - <NUM>.

Preferably, the filter element <NUM> has filtration class G2, G3 or G4 according to the classification of the CEN EN <NUM> standard.

Preferably, the separation element <NUM> comprises a or more perforated portions, which thus define the passages <NUM>, in correspondence with which one or more filter elements <NUM> are mounted so as to completely cover the passages themselves.

Preferably, the outlet section <NUM> of the inlet duct <NUM>, which has passed through the hole 26a of the base portion <NUM>, then engages by interference within the through hole 90a of the filter element <NUM>.

Conveniently, the filter element <NUM> can be mounted on the separation element <NUM> and, preferably, is mounted on a folded edge of the base portion <NUM> which defines the separation element <NUM>.

Advantageously, a lower frame <NUM> can be provided which is configured to mechanically engage in a removable manner, preferably interlocking or snap-on, on the separation element <NUM> (preferably on the base portion <NUM> of the separation element <NUM>), below the filter element <NUM>, to thus further support the latter. Preferably, the lower frame <NUM> allows a more stable and correct locking of the filter element <NUM> to the separation element <NUM>. Preferably, the lower frame <NUM> comprises an internal grid zone 60c and an external frame 60a with elastic hooking fins 60b to the base portion <NUM> (see <FIG>).

Conveniently, in a possible embodiment (see <FIG>), the separation means comprise a separation structure <NUM> which delimits said first zone <NUM> internally while said second zone <NUM> is defined outside said structure <NUM>. Said at least one filter element <NUM> being mounted on said separation structure <NUM>. Preferably, in this case, said at least one passage <NUM> comprising the filtering means <NUM> is defined in a separation structure <NUM> which is mounted, integrated and / or supported by the inlet duct <NUM> so that the interior of said structure is in direct fluid communication with the interior of the inlet duct <NUM>. In particular, as said, the first zone <NUM> is defined within a separation structure <NUM>, preferably box-shaped, which is mounted on or supported in a suspended condition by said inlet duct <NUM>, preferably in correspondence with the central portion of the inlet duct <NUM>. Conveniently, the first zone <NUM> defined inside the separation structure <NUM> is in direct fluid communication with the inlet duct <NUM> and is in fluid communication with the second zone <NUM> defined inside the casing <NUM>, only by passing through the filter element <NUM> which is mounted on the separation structure <NUM>, preferably inside the latter. Conveniently, also in this embodiment, the filtration means <NUM> are defined by said at least one filter element <NUM>.

Conveniently, therefore, the assembly formed by the inlet duct <NUM> and the separation structure <NUM> with the filter element <NUM>, thus define a filtration device <NUM>.

More in detail, the separation structure <NUM> can comprise a protruding body <NUM>, box-shaped, which is integrated on the inlet duct <NUM>, preferably in correspondence with the central portion of said inlet duct <NUM>. Conveniently, in this case, the end of the inlet duct <NUM> which is opposite to the inlet one has a blind / closed bottom. Conveniently, the interior of the protruding body <NUM> is in fluid communication with the inlet duct <NUM>, is closed laterally and is open on a face delimited by an edge <NUM>. Furthermore, the separation structure <NUM> comprises a frame <NUM> provided with through openings <NUM>, entirely covered by the filter element <NUM>, and by means <NUM>, preferably snap-fit, to the protruding body <NUM>. More in detail, in a possible embodiment of the frame <NUM>, the latter comprises a frame <NUM> inside which the through openings <NUM> are defined and on which the hooking means <NUM> are provided, which are preferably defined by tabs for elastic attachment to the protruding edge <NUM> of the box-like body <NUM>.

Preferably, the filter element <NUM> is mounted on the frame <NUM> and is held by the latter in such a way as to be kept resting on internal partitions <NUM> of the protruding body <NUM>.

Conveniently, in this embodiment, the frame <NUM> on which the filter element <NUM> substantially acts as a separation element between the first zone <NUM> (which is defined within the separation structure <NUM> and in fluid communication with the inlet duct) and the second zone <NUM> (which is in fluid communication with the entrance of the detection module <NUM> and is defined by the space, which is external to the separation structure <NUM> and which is delimited by the internal walls of the casing <NUM>).

Preferably, the protruding body <NUM> is formed in a single piece with the inlet duct <NUM>.

Conveniently, the first zone <NUM> provided with the filter element <NUM> is associated with the inlet duct <NUM> above the bottom of the duct itself, to thus oblige the gas flow to rise, at least in part, in countercurrent. Preferably, for this purpose, the protruding body <NUM> is connected to the inlet duct <NUM> at a central portion of the latter.

Preferably, the inlet duct <NUM> is mounted inside the casing <NUM> so that its bottom comes into contact with the bottom wall <NUM> of the casing <NUM>, or in any case is in proximity to the latter.

Preferably, one side of the separation structure <NUM> is in contact with the bottom wall <NUM>, or in any case is in proximity to the latter.

Conveniently, the filter element <NUM> is arranged substantially parallel to the longitudinal development direction of the inlet duct <NUM> and, preferably, is perpendicular to the bottom wall <NUM> of the casing <NUM>.

Advantageously, according to the invention, the filter element <NUM> is removably mounted on the respective elements or elements that support it, whether / these are defined by the separation element <NUM> and / or by the lower frame <NUM> and / or by the frame <NUM> and / or by the protruding body <NUM>), thus allowing its removal and possible reuse after proper cleaning.

Conveniently, in the various embodiments, the filter element <NUM> is made of a different material with respect to the more rigid polymeric materials with which the mounting elements are made (ie the separation element <NUM> and / or the lower frame <NUM> and / or the frame <NUM> and / or the protruding body <NUM>) which support it.

Preferably, at least two mounting elements are provided, which - in the examples illustrated and described - are defined by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM>, configured so as to interact operatively with each other and also in such a way as to act in correspondence of at least a part of the opposite faces and / or edges of a corresponding filter element <NUM>.

Preferably, in the various embodiments, the filter element <NUM> is held / clamped by two mounting elements , which are defined in the illustrated examples and described by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM> which interact operatively with each other so as to support the filter element <NUM> by acting in correspondence, of at least one part, of the opposite faces and / or edges of the filter element <NUM>.

Advantageously, the two mounting elements - which are defined in the the examples illustrated and described by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM> - can be configured in such a way as to hold and / or sandwich between them the filter element <NUM>.

Advantageously, the two mounting elements - which are defined in the illustrated examples and described by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM> - are configured to be releasably connected to each other, preferably by means of engagement mechanical interlocking and / or snap action.

Advantageously, the two mounting elements - which are defined in the illustrated examples and described by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM> - can be configured to define a support structure for said filter element <NUM>.

Advantageously, the two mounting elements - which are defined in the illustrated examples and described by the separation element <NUM> with the lower frame <NUM> or by the frame <NUM> with the protruding body <NUM> - can be configured to define a support structure for said filter element <NUM> which, at least in part, is of a cage or lattice, for example in correspondence with the internal grid zone 60c of the lower frame <NUM> or in correspondence with the through openings <NUM> of the frame <NUM>.

Conveniently, in a possible embodiment (cf. <FIG>), the filter element <NUM> is arranged substantially parallel to the direction in which the gas flow passes through or the inlet duct <NUM>.

Conveniently, in a possible embodiment (cf. <FIG>), the filter element <NUM> is mounted substantially angled, and preferably perpendicularly, to the direction in which the gas flow through the inlet duct <NUM>.

In practice it has been found that the invention achieves the intended aim and objects.

Unlike <CIT>, in the solution according to the present invention the filter element is a filter mat (thus allowing to obtain a higher filtering degree) and is positioned and / or retained - preferably in a removable way - between two mounting elements, forming part of the separation means between the first zone and the second zone, which are configured to be mechanically linked together in a removable way. This is particularly advantageous as it allows to obtain and maintain, in correspondence with the separation means, a stable positioning / holding of the mattress filter element (which allows a greater filtering of the dust present in the gas) and, at the same time, allows an assembly quick and safe during the meter production process. Furthermore, the removability of the filter mat inside the chamber defined between the two mounting elements that can be removably linked together allows advantageously to select the mat filter element with filtering capacity that is more suitable each time to the specific needs of the various applications. of use and / or required by sector regulations, as well as allowing easy removal and / or replacement of the mattress filter element when it is saturated, and this without also having to replace the separation means.

Advantageously, the meter according to the present invention thus conforms to the sector regulations, in particular, for example, it conforms to the European standard EN <NUM>: <NUM>.

Furthermore, advantageously, thanks to the channel or channels <NUM> defined inside the inlet duct <NUM> various channels for depositing the powders present in the incoming gas flow are defined, and this in addition to the filtration means <NUM> associated with the separation wall <NUM> Conveniently, in this way, the powders present in the gas flow are not transported by the main gas flow towards the detection module <NUM>, much less towards the possible shut-off valve <NUM>; in this way, the metrological and operating performance of the meter is guaranteed and constant over time.

The present invention has been illustrated and described in a preferred embodiment thereof, but it is understood that executive variations may be applied to it in practice, without however departing from the scope of the invention as defined in the appended claims.

Claim 1:
Gas meter (<NUM>), comprising:
- a containment casing (<NUM>) in which a gas inlet (<NUM>) is defined inside the containment casing (<NUM>) and an outlet (<NUM>) for the exit of the gas from the containment casing (<NUM>),
- a detection module (<NUM>) which is housed inside the containment casing (<NUM>) and which is configured to detect one or more parameters relating to the gas entering the containment casing itself,
- a first zone (<NUM>) and a second zone (<NUM>), both defined inside the casing (<NUM>), said first zone (<NUM>) being in fluid communication with the inlet (<NUM>), said second zone (<NUM> ) being in fluid communication with the inlet of the detection module (<NUM>), the fluidic connection between said first zone (<NUM>) and said second zone (<NUM>) occurring exclusively through at least one passage (<NUM>) comprising filtration means (<NUM>) ,
- said filtration means (<NUM>) comprising at least one filter element (<NUM>) which is mounted on separation means which separate said first (<NUM>) and said second zone (<NUM>) and by the fact that said filter element (<NUM>) is made of material different from that with which said separation means are made,
- said separation means comprising at least two mounting elements (<NUM>, <NUM>, <NUM>, <NUM>) which are configured to be mechanically bonded to each other in a removable manner,
and also characterized by the fact that:
- said filter element (<NUM>) is a filter mat which is positioned and / or retained, preferably in a removable way, between said at least two mounting elements (<NUM>, <NUM>, <NUM>, <NUM>) when they are mechanically linked together.