The present invention relates to a personal respiratory protective equipment provided with alarm system.

In workplaces, in the military field (for protection against the so-called CBRN - Chemical, Biological, Radiological and Nuclear-events) or in the law enforcement field and, in general, in any other application where it is necessary to individually protect the airways, mainly two protection methods are used. The first and most common method consists in filtering, while the second method consists in feeding breathable or "insulating" gas.

The filtration of harmful gases is normally carried out using a personal protection equipment in which the air breathed by the user is passed through a bed of active carbons, or suitable catalysts, in order to retain the gas or transform it into another, nontoxic gas. The filtering mass and the respective container make up what is commonly called the filter of the personal protective equipment. Various types of filters are defined for example by the European standard UNI EN 14387.

The filter can be applied both to a mask provided with a full "face-mask", that is to say, provided with a screen arranged to completely cover the user's face, and to a so-called half-mask, which covers only the user's nose, mouth and chin. The filter can also be applied to a mouthpiece which is retained between the user's teeth. All of this personal respiratory protective equipment is regulated by the European standards UNI EN 136 and UNI EN 149. For example, in a filtering mask, the depression caused by the user's lungs in the face-mask makes the air, before reaching the lungs themselves, pass through the filtering mass contained in the filter, thus being purified.

The main problems that afflict the filtering masks and, more generally, the personal respiratory protective equipment, relate to the duration of the filter in terms of use and the need to know the exact moment when the filter needs to be replaced. These problems are closely related to some external variables, including the nature of the gas that is to be filtered, its concentration, humidity and air temperature, as well as the user's respiratory capacity (in liters per minute) .

None of the above variables is known a priori, so one tends to change the filter whenever the smell of a potentially harmful gas is perceived. In fact, in the great majority of cases the olfactory threshold, although individually variable, is lower than the danger threshold of the gas {"threshold limit value", or TLV) . Examples of these gases may be hydrogen sulphide (¾S) or ammonia (NH ₃ ) .

However, there are also odorless harmful gases, such as carbon monoxide (CO) , or with olfactory thresholds higher than the TLV, such as formaldehyde (CH ₂ O) . In these cases, the tip of replacing the filter when perceiving the gas appears totally inadequate and resort must therefore be made to preventive scheduled replacements, as dictated by common sense. It is therefore clear that this strategy, in addition to the intrinsic risk, leads to an increased consumption of filters, since they cannot be used to full capacity, with a clear economic damage.

Another problem which afflicts facial masks is the so-called inward leakage. In fact, the adaptation of a face-mask to the user's face may not be perfect, since the physical conformation of the face-mask is fixed, being obtained from a mold, while that of the face is variable from person to person. Moreover, in one person this conformation may change over time due to slimming or fattening, to sweating and to the possible presence of a beard, sideburns or hair that interfere with the sealing edge of the face-mask.

In addition, the inward leakage is influenced by the exhalation valves of the mask, from which the exhaled air escapes into the environment, which in the closing step may have a small reflux. The sum of all these factors determines the total inward leakage (TIL) defined in the European Standard UNI EN 13274-1. The industry standards, such as UNI EN 136 or UNI EN 149, define the maximum admissible limit of TIL.

If the personal respiratory protective equipment consists of an insulating system of any kind (open- circuit air, closed-circuit oxygen, air fed from the line, both upon request and flow-through self- breathing) , of course the problem of exhaustion of the filter does not exist. However, in some cases one may want to know whether there is an inward leakage such as to expose the operator to hazards (see in this regard the European standard UNI EN 137) .

To check the good fit of the face-mask to the user's face, prior checking methods are spreading called fit tests, periodically carried out on the operators. However, these checking methods are carried out "off-line", that is, in a simulated environment and with specially adapted masks.

In environments where the personal respiratory protective equipment is used, it is frequent to use personal portable monitors to check the environmental conditions, in particular the concentration of gas or gases present, to warn when the danger threshold (TLV) or in any case, a predetermined concentration level, is reached. When this happens, the operator must immediately wear the suitable protective equipment. Monitors are normally also provided with a sensor for oxygen, since the breathing filters can be used only in the presence of at least 17% O2 in a percentage volume/volume (% v/v) concentration. This parameter must be taken into account to decide whether to use a filter or an insulating system and must be kept under control, like the concentration of the toxic gas, throughout the operation.

Personal electronic monitors, with regard to the sampling system, are of two types: diffusion and with pump. Diffusion monitors are carried by applying them to garments and they check the presence of gas only locally, since the gas diffuses naturally inside the sensor with which these monitors are provided. Monitors provided with pump are normally used to check from the outside, before the operation, the presence of gas in confined spaces such as tanks, sewers, basements, etc.

Colorimetric tubes are also available which perform tasks similar to those of the electronic monitors described above. However, if on the one hand all the control instruments described above allow the identification of which type of protective equipment must be used and when the breathing device must be worn, on the other hand they leave unresolved the problems of deciding when to change the filter and how to check whether there is inward leakage.

The general object of the present invention therefore is to provide a personal respiratory protective equipment which is capable of solving the above drawbacks of the prior art in an extremely simple, cost-effective and particularly functional manner .

In detail, it is an object of the present invention to provide a personal respiratory protective equipment which is capable of accurately warning the user when it is necessary to change the filter of the equipment itself.

Another object of the invention to provide a personal respiratory protective equipment which is capable of accurately warning the user about any malfunctions of the equipment itself, such as the occurrence of the so-called inward leakage.

These and other objects according to the present invention are achieved by a personal respiratory protective equipment as described in claim 1.

Further features of the invention are highlighted in the dependent claims, which are an integral part of the present description.

The features and the advantages of a personal respiratory protective equipment according to the present invention will become apparent from the following exemplary and non-limiting description, made with reference to the accompanying schematic drawings, in which:

figure 1 is a perspective view of a first exemplary embodiment of the personal respiratory protective equipment according to the present invention;

figure 2 is a perspective view of the equipment in figure 1, shown in a disassembled configuration;

figure 3 is a perspective view of a second exemplary embodiment of the personal respiratory protective equipment according to the present invention;

figure 4 is a perspective view of the equipment of figure 3, shown in a disassembled configuration;

figure 5 is a perspective view of a third exemplary embodiment of the personal respiratory protective equipment according to the present invention;

figure 6 is a perspective view of the equipment of figure 5, shown in a disassembled configuration; and figure 7 is a perspective view of a fourth exemplary embodiment of the personal respiratory protective equipment according to the present invention, shown in a disassembled configuration.

Figure 8 is another perspective view of the device of Figure 7, associated to an external control unit.

It is noted that, in the accompanying figures and in the description that follows, numerous components of the personal respiratory protective equipment will not be mentioned and/or illustrated in that they are components well known to a person skilled in the art.

With reference to the figures, some preferred embodiments of the personal respiratory protective equipment according to the present invention, wholly indicated by the reference numeral 10, are shown. Equipment 10 comprises a filtering assembly 12 operatively connected to a breathing element 14 and configured to feed filtered air to such a breathing element 14. To this end, the filtering assembly 12 is internally provided with at least one filtering element (not shown) through which the external air passes to be then conveyed towards the breathing element 14.

The breathing element 14 is configured to be applied on a user's face. The breathing element 14 may therefore consist, for example, of a helmet of turbo- ventilated filtering system or a mask provided with a full face-mask, that is to say, a screen arranged to completely cover the user's face, of a half-mask, which only covers the user's nose, mouth and chin, or of a mouthpiece. In the case of a helmet or a mask provided with a full face-mask, the breathing element 14 may conveniently be provided with sealing means against the user's face.

As shown in figures 3 and 4, between the filtering assembly 12 and the breathing element 14 at least one connection component 16 may be interposed, configured to mutually connect the filtering assembly 12 and the breathing element 14 and for conveying the filtered air towards such a breathing element 14. The connection component 16 may for example consist of a nipple.

On a predefined portion of equipment 10, located downstream of the filtering element with reference to the air flow flowing within the equipment 10 itself, at least one connection duct 18 is obtained, placed in fluid connection with at least a control apparatus 20. The control apparatus 20 is arranged to analyze the filtered air exiting from the filtering element and to generate at least one visual and/or sound alarm signal in a condition in which such a filtered air does not comply with certain predefined parameters, such as a concentration of harmful gases higher than a predefined threshold .

The control apparatus 20 may for example consist of an electronic monitor provided with at least one suction pump and one or more sensors configured to analyze in real time the filtered air exiting from the filtering element. The control apparatus 20 may not be provided with a suction pump, as it will be better described below. The data related to the filtered air can then be made available on the monitor for immediate display by the user of equipment 10. The sensors of the control apparatus 20 may be calibrated according to the risk assessment document (RAD) of the specific environment in which one wants to work wearing equipment 10.

At least one probe pipe 22, of predefined length, and preferably of the flexible type, may be interposed between the connection duct 18 and the control apparatus 20. The probe pipe 22 allows the control apparatus 20 to be kept separate with respect to equipment 10 and to be easily handled by the user according to requirements.

Both the control apparatus 20, and the respective probe pipe 22, when provided, may be removable with respect to equipment 10. To this end, the connection duct 18 can be provided with a sealably closing element (not shown) configured to close such a connection duct 18 when the control apparatus 20 and/or the respective probe pipe 22 are not operatively connected to equipment 10 itself.

With reference to the embodiment in figures 1 and

2, the connection duct 18 is obtained on the filtering assembly 12, of course downstream of the filtering element. With reference to the embodiment in figures 3 and 4, on the other hand, the connection duct 18 is obtained on the connection component 16 interposed between the filtering assembly 12 and the breathing element 14.

With reference to the embodiment in figures 5 and 6, the connection duct 18 is obtained on the breathing element 14. While in the two embodiment in figures 1-4 the control apparatus 20 is able to signal the exhaustion of the filtering element only, in this third embodiment of equipment 10 it is also possible to check whether the face-mask of the breathing element 14 has a sufficient seal on the user's face. However, any alarm signal generated by the control apparatus 20 is not able to distinguish where the gas has penetrated from, but is only able to warn the user that there is a situation of danger.

During expiration, in the breathing element 14 (if such a breathing element 14 consists of a helmet or a full face-mask and sealing means on the user's face are therefore provided) , a positive pressure is generated, while in the inspiratory steps, the pressure will be negative. The UNI EN 136 standard, for example, indicates a maximum value of 3 mbar for expiration. UNI EN 137 standard indicates a maximum value of 10 mbar in the case of positive-pressure systems. In any case, it can be deemed that the internal pressure of the breathing element 14, especially in the second case mentioned, is sufficient to bring a suitable gas flow to the sensors of the control apparatus 20 through the connection duct 18. Therefore, the control apparatus 20 may also be not provided with integrated pump, with the advantage of increasing the battery life and/or lightening the control apparatus 20 itself.

Finally, with reference to the embodiment in figure 7, equipment 10 may be provided with an integrated control apparatus 20 in the breathing element 14. In this case, the connection duct 18 is eliminated, since the control apparatus 20 is of the diffusion type, i.e. without pump.

The control apparatus 20 may be accommodated inside the breathing element 14 and may be provided with one or more containers 24 enclosing sensors and/or batteries. Alternatively, the control apparatus 20 can be applied externally to the breathing element 14 and can be provided with one or more sensors "facing" the breathing zone, that is, arranged into the breathing element 14.

The control apparatus 20, when integrated into the breathing element 14, can be designed to generate light (LED) and/or sound alarms set at the levels corresponding to the TLV of the substance from which one must be protected, or to predetermined levels anyway. Two or more threshold levels may be provided. Alternatively, it a "Head Up Di splay" (HUD) may be provided which projects the concentration data on a screen of the breathing element 14 to have an instant reading .

The control apparatus 20, when integrated into the breathing element 14, can be autonomous in all functions, but it could also provide for a wireless communication system with a control unit 26 external to equipment 10. Such an external control unit 26 may be provided with an integrated display for reading the gas concentrations detected and the setting parameters. Such an external control unit 26 may also be used independently, i.e. separately from the control equipment 20 integrated in the breathing element 14 to analyze the work environment. Such an external control unit 26 may therefore also consist of a smartphone, a tablet or a remote PC provided to the person responsible for the activity carried out by the user of equipment 10.

Also in the fourth embodiment of equipment 10, it may checked whether the face-mask of the breathing element 14 has a sufficient seal on the user's face. Obviously with the third and fourth embodiments of equipment 10, if referring for example to a situation of seal loss of the face-mask of the breathing element 14, there will be no precise information on the instant in which it is necessary to replace the filtering element, but the object of preventing the user's exposure to a gas concentration higher than acceptable will still be achieved. The third and fourth embodiments of equipment 10 are also usable with insulating systems and also in this case, their function is to forewarn the user in case of potential infiltrations of toxic gas into the protective system, wherever they occur. It has thus been seen that the personal respiratory protective equipment according to the present invention achieves the objects described above.

The personal respiratory protective equipment according to the present invention therefore allows solving the question about the actual duration of the filtering element or the seal loss of the face-mask in a simple and cost-effective manner, since all the components of the equipment itself are normally available in the workplace, as well as in a continuous manner and in real time.

The personal respiratory protective equipment of the present invention thus conceived can in any case be subjected to numerous modifications and variants, all falling within the same inventive concept; moreover, all details may be replaced with technically equivalent elements. In the practice, the materials used as well as shapes and sizes, may be any, according to the technical requirements.

The scope of protection of the invention is therefore defined by the accompanying claims.