EP0488880A1 - Protective isolation suit - Google Patents

Abstract

The equipment, which can be used for combating fires, comprises an isolation suit consisting of a flexible and sealed garment (10) and of a helmet (12) having a transparent visor, fitted with a tank of liquefied respiratory gas supplying a respiratory circuit which emerges into the helmet. The respiratory circuit is supplied by the tank via the primary circuit of a heat exchanger. A compressed-air motor is interposed between the heat exchanger (28) and the respiratory circuit and is attached to a fan (34) for circulating air for cooling the garment (10) in a closed circuit passing via the exchanger (28). <IMAGE>

Description

The present invention relates to personal protective equipment in a hostile atmosphere, in particular in an atmosphere containing toxic or corrosive products, comprising a diving suit provided with an autonomous supply of respiratory gas and means of ventilation of the diving suit.

Equipment of this type is already known having a spacesuit consisting of a flexible and waterproof garment and a helmet with transparent visor, connectable to a gas reserve constituted by a supply cylinder of compressed respiratory gas.

During interventions in such an atmosphere, the protective equipment must supply respiratory gas in quantity and appropriate quality and also ventilate the body to evacuate the heat and to avoid condensation.

In general, the gas coming from the bottle feeds an ejector intended to suck in air coming from the spacesuit and to put it in circulation for ventilation. The atmosphere breathed by the wearer of the suit is made up of a mixture of the supplied breathing gas and the suit's gas. The supply of gas from the bottle is compensated by an exhaust through valves fitted to the spacesuit.

These known devices have a number of drawbacks. The ventilation circuit can be considered to be open, which results in wasted respiratory gas. The exhaled gases coming to dilute in the whole atmosphere of the spacesuit, the CO₂ content of these gases increases quickly and can reach a dangerous value.

Such equipment consequently has only a reduced autonomy, owing to the fact that the volume and the weight of the compressed gas cylinders used for respiration and ventilation must remain within acceptable limits.

The pure and simple substitution of a tank of liquid gas for a supply cylinder of compressed respiratory gas leaves most of the above drawbacks to remain.

The invention aims to solve the problem of the protection of personnel having to intervene on the scene of accidents and for this to have equipment which allows physical activity, therefore a high metabolism, for a long period without dangerous increase in the content. CO₂ inspired gases.

To solve this problem, the invention proposes in particular individual protective equipment in which the reserve of respiratory gas consists of a tank of liquefied gas (liquid air, liquid oxygen or liquefied mixture containing helium and / or hydrogen in addition to oxygen and nitrogen) feeding a respiratory circuit opening into the helmet, generally through a regulating valve, which can be of conventional constitution; the equipment is characterized in that the respiratory circuit is supplied by the reservoir through the primary circuit of a heat exchanger and a pneumatic motor interposed between the heat exchanger and the respiratory circuit and is coupled to a circulation fan ventilation air of the garment in a closed circuit passing through the exchanger. In the exchanger, the ventilation gas is cooled and dried before feeding the spacesuit.

The return of the ventilation gas to the spacesuit can be carried out by distribution pipes opening out at the ends of the members, according to an already known arrangement, for example that described in document EP-A-0 317 415. The ventilation circuit can be closed or simply semi-closed, with evacuation of a gas flow, in the case of equipment intended to be used in the atmosphere.

In a particular embodiment of the invention, the face is separated from the atmosphere around the body by a seal (facial seal or more frequently neck seal) and the helmet is provided with an exhalation valve. This creates a simple separation between an open respiratory circuit which passes through the helmet to the atmosphere and the closed ventilation circuit through the garment. The expiration takes place directly outside the spacesuit and it avoids keeping the expired water vapor and carbon dioxide inside the spacesuit.

In another particular embodiment of the invention, only a fraction of the flow of respiratory gas coming from the primary circuit of the exchanger is sent to the pneumatic motor, the rest of the flow of gas supplying the helmet or a respiratory mask by the through an on-demand regulator.

In all cases, an economizer bag, which may have a constitution and a function similar to that of the bags provided on the emergency oxygen masks intended for passengers on commercial aircraft, may be interposed between the outlet of the pneumatic engine and the intake into helmet.

Whichever of these embodiments is adopted, the invention makes it possible to use not only the breathable nature of the reserve gas but also its physical state, the liquefied gas constituting a source of frigories and the pressure of the vaporized gas. providing the energy needed for ventilation.

• la figure 1 montre schématiquement la constitution générale d'un équipement individuel de protection suivant un mode particulier de mise en oeuvre de l'invention, particulièrement simple ;
• la figure 2 montre une constitution possible de l'ensemble turbine-ventilateur incorporé dans l'équipement de la figure 1 ;
• la figure 3 est une vue en coupe schématique d'un moteur pneumatique à palettes pouvant constituer le moteur de la figure 1 ;
• la figure 4, similaire à une fraction de la figure 1, montre une variante de réalisation ;
• la figure 5, similaire à une fraction de la figure 1, montre une autre variante encore de réalisation, permettant un fonctionnement en secours, en cas de défaillance du moteur.

The invention will be better understood on reading the following description of particular embodiments, given by way of nonlimiting examples. The description refers to the accompanying drawings, in which:

• Figure 1 schematically shows the general constitution of an individual protective equipment according to a particular mode of implementation of the invention, particularly simple;
• Figure 2 shows a possible constitution of the turbine-fan assembly incorporated in the equipment of Figure 1;
• Figure 3 is a schematic sectional view of a pneumatic vane motor which can constitute the motor of Figure 1;
• Figure 4, similar to a fraction of Figure 1, shows an alternative embodiment;
• Figure 5, similar to a fraction of Figure 1, shows yet another alternative embodiment, allowing emergency operation in the event of engine failure.

The respiratory equipment shown diagrammatically in FIG. 1 comprises a suit having a garment 10 and a helmet 12 provided with a transparent visor 14. The helmet is provided with an exhalation valve 15 provided to maintain an overpressure of a few around the head. millibars compared to the ambient atmosphere. A neck seal 16 which is applied against the skin separates the space surrounding the head from the space surrounding the rest of the body. This neck seal 16 can be replaced by a facial seal or an oro-nasal mask. The garment is equipped with a network of pipes to organize the circulation of ventilation gas along the limbs and torso. In the embodiment given by way of simple example, this network of pipes includes a distributor 18 between pipes 20 for supplying gas to the ends of the members, the return being effected by circulation along the members towards the space surrounding the torso. The garment is equipped with a calibrated valve or more, 22 maintaining an overpressure in the spacesuit. This overpressure will often be around 2 millibars in the case of use of the spacesuit in an atmosphere under normal atmospheric pressure. It is sufficient to prevent the flooding of the suit with toxic or corrosive products from outside.

In a pocket adjacent to the garment 10, or even inside this garment, is placed a reserve of respiratory gas constituted by a reservoir 24 of liquefied breathable gas. This tank belongs to a converter whose general constitution is similar to that of the converters currently used in military aircraft to supply the crew with respiratory gas. It is fitted with a conventional pressure regulator, at 5 bars for example (not shown), and supplies the coil 26 constituting the primary circuit of a heat exchanger 28.

In the embodiment shown in FIG. 1, the output of the coil 26 feeds a rotary pneumatic motor 30, the output of which is connected to a pipe 32 which opens into the helmet 12. An economizer bag 46 (in dashes in FIG. 1) can be connected to line 12. The respiratory gas which reaches the helmet cannot therefore in any case mix with the gas occupying the interior of the garment. The motor 30 is coupled to a fan 34 intended to take gas from the garment 10 and to circulate it in the exchanger 28, where this withdrawn gas cools and dries out. For this, the heat exchanger 28 may comprise a casing 36 for guiding the gas, provided at its base with means for discharging the condensates, which can be reduced to a tube 38 of small section.

In this case, the upper part of the envelope 36 can be simply opened widely above the fan 34, so as to collect gas in the garment 10. The lower part of the envelope 36 feeds a sheath 40 which opens into the distributor 18. The collected gas passes through the fan 34, scans the coil 26, passes through the distributor 18 and from there is sent to the ends of the members.

The motor 30 and the fan 34 can have very diverse constitutions. FIG. 2 shows a motor 30 constituted by a turbine whose output shaft carries a fan propeller 34. The diameter of the turbine can be much smaller than that of the fan propeller, since the flow rate passing through the turbine is much lower than that which must pass through the secondary circuit of the exchanger. For example, for a flow of 8 to 15 l / min through the turbine, the flow of the fan will generally be between 150 and 200 l / min. On the other hand, the supply pressure of the motor can be several bars while a few millibars are enough to overcome the pressure losses of the ventilation circuit. The air supply to the fan can therefore take place through an annular space formed around the turbine. The supply of respiratory gas to the turbine and the departure of gas can be carried out by small diameter pipes.

The motor 30 can have other constitutions: in particular, it can be constituted not by an expansion turbine, but by a volumetric machine, such as for example the pneumatic vane motor shown in FIG. 3. The rotor 42 which carries the pallets 44 is still coupled to the fan 34.

In the alternative embodiment shown in FIG. 4 (where the members already represented in FIG. 1 are designated by the same reference number) only a fraction of the respiratory gas vaporized in the coil 26 of the exchanger 28 passes through the turbine 30. This solution in particular allows the turbine 30 to pass through at a rate which varies little; the exceptional calls for respiratory flow in the event of effort pass through a demand regulator, which can be conventional, mounted in bypass.

More precisely, the output of the coil of the exchanger 28 is connected to two circuits opening into the helmet.

The first circuit is similar to that which is mounted in FIG. 1, but comprises a flexible economiser bag 46, contained in the garment and having a volume of the order of a liter when it is inflated. This bag 46, placed upstream of the outlet in the helmet 12 and downstream of the motor 30, adapts the continuous flow of the pneumatic motor 30 at the alternating flow of respiration, without increasing consumption.

The second circuit includes a demand regulator 48 having a reference pressure tap in the helmet to control the flow. It feeds a diffuser 50 for demisting the visor 14, opening into the helmet.

Thanks to this arrangement, the expiration is normally done directly towards the environment, out of the spacesuit, which avoids conserving the expired water vapor and carbon dioxide.

Intermediate solutions, repeating only part of the arrangements shown in FIG. 4, are also possible.

The variant embodiment shown in FIG. 5 differs from the previous one by selection means making it possible to supply the secondary circuit of the exchanger 28 either through the fan 34 (normal operation) or through a suction ejector 58 air in the garment.

These selection means comprise a three-way valve 60, with manual control or with automatic control in the event of a malfunction of the motor-vacuum cleaner assembly. In a first position, the valve 60 sends a fraction of the gas leaving the primary circuit of the exchanger to the pneumatic motor 30. In its second position, it sends this fraction of the gas to the ejector 58.

To avoid that, in the second case, the mixture sucked by the ejector does not escape through the fan 34, a non-return valve 62 is interposed on the air intake to the fan. Another valve 64 is interposed on the inlet to the ejector.

The invention is not limited to the particular embodiments which have been shown and described by way of examples and it should be understood that the scope of the present patent extends to all variants remaining within the framework of equivalences.

Claims (6)

Personal protective equipment in a hostile atmosphere, comprising a spacesuit consisting of a flexible and waterproof garment (10) and a helmet (12) with transparent visor, provided with a tank of liquefied respiratory gas supplying a respiratory circuit opening into the helmet, characterized in that the respiratory circuit is supplied by the reservoir through the primary circuit of a heat exchanger and in that a pneumatic motor is interposed between the heat exchanger (28) and the respiratory circuit and is coupled to a garment ventilation air circulation fan (34) in a closed circuit passing through the secondary circuit of the exchanger (28). Equipment according to claim 1, characterized in that the helmet (12) is provided with means for isolating the respiratory tract from the wearer and is provided with an exhalation valve (15) calibrated to maintain an overpressure in the part which covers the face and receives the outlet of the respiratory circuit. Equipment according to claim 2, characterized in that said isolation means consist of a neck seal, a face seal or an oro-nasal mask. Equipment according to claim 1, characterized in that the helmet is provided with means, such as a neck seal (16), for isolating the face of the wearer and in that only a fraction of the flow of respiratory gas coming from the circuit primary (26) of the exchanger (28) passes into the pneumatic motor (30), the rest of the gas flow supplying the part of the helmet (12) covering the face or a respiratory mask via a regulator the request (48) for adaptation to the wearer's breathing. Equipment according to any one of the preceding claims, characterized by an economiser bag (46) placed in the garment and interposed on the circuit supply of the helmet with respiratory gas. Equipment according to any one of the preceding claims, characterized by selection means making it possible to supply the secondary circuit of the exchanger 28 either through the fan 34 (normal operation), or through an ejector 58 for suction from air in the garment.

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