DESCRIPTION

The present invention concerns an odorizer device suited to odorize the gas, for example natural gas or a similar gas, that flows along a gas distribution network.

It is known that, for safety reasons, natural gas is mixed with an odorizing substance before being distributed to the utilities.

Typically, the odorizing substance is a liquid and is let evaporate in the gas. The presence of the above mentioned odorizing substance allows users and operators to perceive and become aware of any gas leakages from the gas distribution network.

According to a known technique, which can be defined as "capillarity-based", gas is odorized by means of a wick having one end arranged in the duct in which the gas flows and the other end immersed in a reservoir that contains the odorizing substance.

The odorizing substance is absorbed by the wick and owing to capillarity proceeds towards the end positioned in the duct, where it evaporates due to the effect of the gas flow that comes into contact with the wick.

The above mentioned known technique poses the drawback that it does not ensure a reliable dosing of the odorizing substance.

In fact, for a given wick and for a given gas, the dosing of the odorizing substance essentially depends on the area of the wick exposed to the gas flow, on the position of the wick in the duct and on the gas speed.

In practice, neither the length of the wick portion introduced in the duct nor the position assumed by the wick in the gas flow can be controlled with precision. Consequently, the drawback arises that the percentage of odorizing substance mixed with the gas can oscillate considerably, even to the point of lying outside the range of values established by the applicable safety rules.

A further drawback posed by the above mentioned technique is represented by the fact that it does not allow the flow rate of the odorizing substance evaporating from the wick to be adjusted in an easy and reliable manner.

Said adjustment is necessary in particular in the case of variations in the flow rate of the gas flowing in the duct, due for example to the normal seasonal oscillations in gas consumption.

In fact, for a predefined area of the wick exposed to the gas flow, the flow rate of the odorizing substance evaporating from the wick is not proportional to the flow rate of the gas flowing in the duct.

In practice, the flow rate of the odorizing substance evaporating from the wick increases less than proportionally to the flow rate of the gas itself, leading to a corresponding reduction in the concentration of odorizing substance mixed with the gas.

In the attempt to solve the drawbacks described above, a known variant embodiment of the odorizer device described above has been developed, in which it is possible to adjust the length of the portion of the wick which is exposed inside the duct.

Even in this embodiment, however, the flow rate of the odorizing substance cannot be adjusted with precision, in fact it is only possible to control the length of the exposed wick portion, but not its position.

Therefore, the wick will tend to assume different positions inside the duct, depending on the length of said exposed portion and on the gas speed, so that the relation between the flow rate of the evaporated odorizing substance and the exposed area of the wick changes in a manner that cannot be foreseen.

The present invention intends to overcome all the drawbacks of the known art that have been described above.

In particular, it is one of the first objects of the present invention to provide an odorizer device of the capillarity-based type, which makes it possible to adjust the flow rate of the odorizing substance evaporating in the gas flow in a reliable manner.

It is also the object of the invention to provide an odorizer device in which said adjustment can be carried out in a simple and rapid manner, with no need to disassemble the device and release an undesirable gas odour in the environment.

It is another and not less important object of the invention to provide an odorizer device that is simple to construct.

The objects mentioned above are achieved by an odorizer device carried out according to the main claim.

Further characteristics and details of the odorizer device that is the subject of the invention are illustrated in the corresponding dependent claims.

Advantageously, the possibility to adjust the device in a simple and reliable manner makes it easier to maintain the concentration of odorizing substance in the gas within a limited range of values, even in case of variations in the gas flow rate.

Still advantageously, the simple and quick adjustment of the device makes it possible to reduce adjustment times and, therefore, labour costs.

Said objects and advantages, together with others that are described here below, are highlighted in the description of a preferred embodiment of the invention which is provided by way of non-limiting example with reference to the attached drawings, wherein:

- Figure 1 shows an axonometric view of the odorizer device that is the subject of the invention;

- Figure 2 shows a side sectional view of the odorizer device of Figure 1 ;

- Figure 3 shows an enlarged detail of Figure 2;

- Figure 4 shows the odorizer device of the invention in an operating configuration.

The odorizer device of the invention, indicated as a whole by 1 in Figure 4, is particularly suited to be used to odorize natural gas or a similar gas flowing in a duct 29 of a distribution network.

As can be observed in Figures 1 and 2, the device 1 comprises a tubular jacket 10 developed according to a longitudinal axis X.

The device 1 furthermore comprises a containment element 2 sliding in the tubular jacket 10 according to the longitudinal axis X between a first position, in which an end portion 8 of the containment element 2 is arranged so that it is extracted from the tubular jacket 10, and a second position, in which the end portion is arranged so that it is retracted into the tubular jacket 10.

The tubular jacket 10 can be connected to the duct 29 in a stable manner through coupling means 13, in such a way that the end portion 8 faces towards the inside of the duct 29, as can be observed in Figure 4.

The containment element 2 defines a cavity 2a that develops according to the direction of the longitudinal axis X between an inlet mouth 3, opposing said end portion 8, and a plurality of separate outlet mouths 7 defined on the external surface of the end portion 8 and arranged at the level of respective distinct positions according to the longitudinal axis X.

In particular, the outlet mouths 7 are arranged in such a way that they can all be placed inside the tubular jacket 10 following the complete retraction of the end portion 8, so that they are all closed. Preferably but not necessarily, each outlet mouth 7 is a hole with cylindrical cross section.

According to a variant embodiment of the invention, not illustrated in the drawings, one or more outlet mouths 7 are in the shape of corresponding slits mainly developed according to the direction of the longitudinal axis X.

In a further variant embodiment of the invention there is only one outlet mouth 7 in the shape of a slit.

According to further variant embodiments of the invention, not illustrated in the drawings, outlet mouths 7 can be provided which are carried out as a combination of the embodiments just described above.

In any case, the outlet mouths 7 overally extend over a section of the longitudinal axis X having a length exceeding the maximum width of the outlet mouths 7 in a direction that is orthogonal to the longitudinal axis X.

Furthermore, the outlet mouths 7 are configured in such a way that they are closed by the tubular jacket 10 when the containment element 2 is arranged in said second position.

Said configuration is such that the overall stroke of the containment element 2 that is required to uncover the outlet mouths 7 completely exceeds the width of the latter, so as to allow their progressive opening.

The device 1 comprises also a feeding element 9 suited to absorb an odorizing substance 28, said feeding element being housed in the cavity 2a with an end 9a projecting from the inlet mouth 3 and the opposite end arranged inside the cavity 2a itself.

Preferably but not necessarily, the feeding element 9 is a wick, even if in variant embodiments of the invention it can be constituted by any element suited to absorb the odorizing substance 28 and let it out through evaporation.

Preferably, the feeding element 9 is blocked axially with respect to the containment element 2 through fixing means that are not illustrated in the drawings but are known per se.

Gas tight means 11 suited to prevent the gas that flows in the duct 29 from leaking outside through the device 1 are interposed between the tubular jacket

10 and the containment element 2.

Said gas-tight means 11 preferably comprise two sealing rings arranged in corresponding housings obtained in the side of the tubular jacket 10 facing the containment element 2. Clearly, according to variant embodiments of the invention, said gas- tight means 11 can be present in a different number and/or can have a different shape than described above, provided that they are suited to prevent any gas leakage between the tubular jacket 10 and the containment element 2.

The device 1 comprises also adjusting means 12 that maintain the containment element 2 in axial position with respect to the tubular jacket 10 but that can be operated in such a way as to cause the containment element 2 to slide in the tubular jacket 10 so as to modify said axial position.

In particular, said sliding movement is such as to allow the end portion 8 to be retracted in the tubular jacket 10 and to be extracted from the same.

In the configuration shown in the figures, the end portion 8 is completely extracted and, therefore, the outlet mouths 7 are all exposed to the gas flowing in the duct 29.

In this way, the odorizing substance 28 can evaporate from the cavity 2a through the entire cross section of the outlet mouths 7, so as to odorize the gas.

Starting from the configuration mentioned above and acting on the adjusting means 12, it is possible to retract the end portion 8 of the containment element 2 into the tubular jacket 10, in such a way as to obtain the more or less partial obstruction of the outlet mouths 7 and, consequently, to adjust the passage area for the odorizing substance 28.

Obviously, said adjustment takes place in an analogous way in all the variant embodiments of the device 1 described above.

It can be understood that, for a given configuration of the outlet mouths 7, said passage area is independent of the gas speed and depends only on the position of the containment element 2 with respect to the tubular jacket 10.

In particular, as the feeding element 9 does not project through the outlet mouths 7, it maintains its position independently of the gas speed.

Consequently it is possible, for example through laboratory tests, to establish a relation between the speed of the gas that comes into contact with the end portion 8 and the area of the outlet mouths 7 which has to remain exposed as a whole in order to maintain the concentration of the odorizing substance 28 in the gas within the pre-established limits.

Therefore, the invention achieves the object to make the adjustment of the flow rate of the odorizing substance 28 simpler and more reliable. In the variant in which the outlet mouths 7 are a plurality of distinct openings, the adjustment takes place through discrete variations that depend on the number of openings exposed to the flow.

Therefore, said variant offers the additional advantage that it does not require high precision in the positioning of the containment element 2 with respect to the tubular jacket 10, thus further increasing the ease of adjustment of the device 1.

Preferably, the feeding element 9 is arranged in the cavity 2a in such a way that it faces all the outlet mouths 7 over their entire length.

Advantageously, said layout ensures the efficient evaporation of the odorizing substance 28 through all of the outlet mouths 7 and, therefore, increases the reliability of the adjustment operation.

Preferably, the outlet mouths 7 constitute the only ways of communication towards the outside of the cavity 2a through the end portion 8.

Advantageously, said configuration ensures that the evaporation of the odorizing substance 28 in the duct 29 takes place exclusively through the outlet mouths 7, in such a way as to make it possible to interrupt the distribution of the odorizing substance 28.

Preferably, the condition described above is obtained by means of a sealing ring 18 belonging to the end portion 8 and configured in such a way that it can be arranged against a reference surface 19 defined on the tubular jacket 10 so as to prevent the outflow of the odorizing substance 28 through the outlet mouths 7.

Advantageously, said sealing ring 18 makes it possible to completely close the odorizer device 1 towards the duct 29, which is useful, for example, during maintenance operations or when it is necessary to interrupt the distribution of gas.

The sealing ring 18 may belong to a plug 5 connected to the end portion 8, for example through a screwing action.

As regards the shape of the outlet mouths 7, preferably their width in the direction perpendicular to the longitudinal axis X generally decreases as their distance from the inlet mouth 3 increases.

The applicant of the present invention has observed that said variation in the cross section of the outlet mouths 7 makes it possible to establish a substantially proportional relation between the gas flow rate and the overall length of the outlet mouths 7 which are extracted, in order to obtain the predetermined concentration of odorizing substance 28.

In the case where the outlet mouths 7 are constituted by a plurality of holes arranged in different positions along the longitudinal axis X, the condition described above is obtained by defining for said holes diameters that decrease as their distance from the inlet mouth 3 increases.

If, instead, there is just one outlet mouth 7 in the shape of a slit, said requisite can be met by making the slit with decreasing cross section towards the end opposite the inlet mouth 3.

If there are outlet mouths 7 in the shape of holes, these are preferably arranged at regular intervals along the longitudinal axis X, in such a way that the number of holes which are extracted is proportional to the length over which the containment element 2 slides in the tubular jacket 10.

As regards the adjusting means 12, they preferably comprise screw means that connect the containment element 2 to the tubular jacket 10, are suited to maintain the mutual axial position of the two elements and at the same time can be rotated in such a way as to adjust said mutual axial position.

Preferably and as shown in Figure 3, said screw means comprise a first sleeve 14 provided with a first inner thread 15 that is coupled with a corresponding outer thread 16 belonging to the tubular jacket 10 and with a second inner thread 15a that is coupled with a corresponding outer thread 17 belonging to the coupling element 2 and having opposite direction with respect to the outer thread 16.

Obviously, by rotating the first sleeve 14 and maintaining the relative angular position between the containment element 2 and the tubular jacket 10 unchanged, it is possible to obtain opposing sliding movements of the two components with respect to the first sleeve 14 according to the longitudinal axis X, thus allowing an easy and quick adjustment of the device 1.

In order to maintain a fixed relative angular position between the containment element 2 and the tubular jacket 10, one or both of the components are preferably provided with corresponding notches, not illustrated in the drawings, which allow the operator to check the angular position of the two components. According to a variant embodiment of the invention, not illustrated in the drawings, the first sleeve 14 is axially constrained to the containment element 2 or to the tubular jacket 10 and is coupled only to the other one of said two components through screw means.

Preferably, the odorizer device 1 comprises reference notches, not illustrated in the drawings, on the first sleeve 14 and/or on the containment element 2 and/or on the tubular jacket 10, said reference notches being suited to indicate to the operator the length of the portion of the outlet mouths 7 facing towards the outside of the tubular jacket 10 during the adjustment of the device 1.

Said notches can be arranged in different positions according to the longitudinal axis X at the level of those surfaces of the containment element 2 and/or of the tubular jacket 10 that are progressively uncovered by the first sleeve 14 during the adjustment.

Preferably but not necessarily, the adjusting means 12 comprise also locking means, not illustrated herein but known per se, which can be activated at the end of the adjustment operation in order to prevent any further accidental rotation of the first sleeve 14 due, for example, to vibrations or other causes. Said locking means may comprise, for example, a fixing dowel.

As regards the coupling means 13 suited to connect the odorizer device 1 to the duct 29, these preferably comprise a second sleeve 20 provided with connection means for stable connection to the tubular jacket 10.

Preferably, said stable connection means comprise a stop surface 21 suited to be arranged against a corresponding reference surface 22 belonging to the tubular jacket 10, sealing means 23 being provided that prevent the passage of gas between the second sleeve 20 and the tubular jacket 10 and that preferably comprise an annular gasket.

Preferably, said stable connection is obtained by screwing the second sleeve 20, provided with an inner thread 24, to the tubular jacket 10, provided with a corresponding outer thread 25, until the stop surface 21 comes to be positioned against the reference surface 22.

Said second sleeve 20 is associated with the duct 29 through a welding operation or using any other equivalent connections means of the known type. Preferably and as shown in Figure 4, the odorizing substance 28 is contained in a reservoir 26 provided with a mouth 27.

The odorizer device 1 comprises joining means 6 for the tight coupling of the containment element 2 with said mouth 27, in such a way that the inlet mouth 3 of the cavity 2a is in communication with the inside of the reservoir 26.

Preferably, said joining means 6 comprise an outer thread 6a belonging to the containment element 2 and screwed to a corresponding inner thread belonging to said mouth 27 of the reservoir 26.

Preferably, the feeding element 9 has its end 9a that projects beyond the inlet mouth 3, so that the latter can be arranged inside the reservoir 26 in such a way as to effectively absorb the odorizing substance 28 independently of the position of the reservoir 26 with respect to the odorizer device 1.

Operatively, the odorizer device 1 described above can be used after fixing the second sleeve 20 to the duct 29 in which the gas flows, for example through a welding operation, as shown in Figure 3.

Thus, the reservoir 26 is screwed to the odorizer device 1 by proceeding as described above, after which the tubular jacket 10 is screwed to the second sleeve 20, in such a way as to arrange the containment element 2 with its end portion 8 facing the inside of the duct 29.

At this point, it is possible to adjust the odorizer device 1 by acting on the first sleeve 14, as described above.

Advantageously, the odorizer device 1 described above can be easily removed for maintenance purposes or when it is necessary to fill the reservoir 26 with odorizing substance 28.

According to the above description, it can be understood that the odorizer device that is the subject of the invention achieves all of the set objects.

In particular, the position of the feeding element inside the containment element and the configuration of the outlet mouths facilitate the adjustment of the odorizer device, making it a quick and reliable operation.