Pressure Gas Ventilated Protective Suit and Method of Operating the Suit

This invention relates in general to protective suits and in particular to a new and useful pressure gas ventilated suit which includes a body portion which is under separate pressure and which is connected through a breathing space of a head portion through an inhaling valve.

Protection against contaminated gases or gases with concentrations which lead to skin injuries, can only be effected with protective suits which seal the body hermetically from the ambient atmosphere. Protection against radioactive gases, as they appear, e.g. in nuclear reactors, nuclear power plants and isotope laboratories, requires protective suits which prevent the body of the protective suit wearer from coming in contact with radioactive dusts or gases or radiation. It cannot be prevented that radioactive particles will be deposited on the outer surface of the suit. The radiation hazard for the wearer decreases with the distance of the suit material from body surface. The protective suit should therefore not bear tightly on the body, but the distance between the suit wearer and the suit cover should be as great as possible.

A known protective suit seals at the arms and legs or on the gloves and boots by elastic cuffs. The hood seals a gas mask.

The user carries on his back a compressed air tank apparatus. The breathing air is supplied over the usual dosing device through an inhaling hose to the gas mask, and thus to the wearer. The exhaled air is introduced into the protective suit from the mask through a hose into which a water separator is connected. It flushes the protective suit and leaves it again through leaks provided for this purpose. These leaks can be special check valves.

The resulting slight excess pressure inflates the suit only incompletely. This is particularly undefined in movements of the suit wearer and underpressures are not possible. A disadvantage is also the high temperature of 37.degree. C. of the exhaled air. The compressed tank apparatus, the breathing air lines, and the water separator outside the suit are extremely annoying and are exposed directly to contamination (German Utility Model No. 17 44 688).

Another known protective suit ventilated with pressure gas also covers the compressed air respirator. But the protective suit can also be supplied directly from the outside through a compressed air hose. In both cases the compressed air is split into a first partial current flowing through an accordion hose to the oxygen mask, and into a second partial current to a jet pump.

The first partial current is inhaled as breathing air, controlled over a lung demand valve and exhaled again through an exhaling valve on the mask into the protective suit. The second partial current drives the jet pump, which takes in its supply air over a dry cartridge from the interior of the suit, hence also the exhaled air, and distributes through lines in the protective suit. Outlet valves in the protective suit conduct an amount of flushed air corresponding to the amount of exhaled air constantly to the outside. The temperature of the air exhaled into the suit increases the inside temperature on the protective suit. The compressed air used for the operation of the jet pump is lost for breathing. It shortens the possible time of use in an operation with compressed air cylinders. (German Pat. No. 12 41 713).

The invention provides a protective suit with a respirator, which can be inflated up to a selected pressure, uses no additional breathing air for ventilation under optimum climatic conditions for the wearer, and has a simple mechanical design.

The inventive pressure suit provides a suit which is adapted to cover a person and includes a head portion with a face encompassing part which defines a breathing space in front of the face of the wearer and a body portion which defines a pressure space separate from the breathing space. A connection is provided between the breathing space and the pressure space and a check valve in this connection permits flow of air from the pressure space into the breathing space during inhaling of the wearer can also discharge air back into the breathing space and out through an exhaling valve.

The protective suit according to the invention contains an air supply from the compressed air apparatus of the respirator, or directly from a coupled compressed air line of a central supply. The air enters the free space of the protective suit over the pressure regulating valve, practically a positive pressure demand valve, and inflates the suit up to the desired excess pressures. The inhaling air is taken by the wearer from an inflated free space in the suit through a check valve between the suit body and a head mask position. Hot exhaled air from the user is conducted directly into the atmosphere. The pressure regulating valve controls the air until it is adapted again to the provided excess pressure. Breathing air which is withdrawn is cooled by expansion and in this way conducted over the body surface. With the increased breathing air throughput under heavy stresses of the wearer, the cooling is automatically improved. The air guiding system leads to a very favorable use of the breathing air supply. The protective suit, hence the free space in the suit body only has to be filled once. Subsequently only so much is used for breathing as would correspond to direct withdrawal from a pressure tank of oxygen. At the end of the use, the free space can be breathed out until the excess pressure in the suit is reduced to the normal pressure. The breathing air supply is thus fully utilized.

Accordingly, it is an object of the invention to provide an improved pressure gas ventilated pressure suit which includes a separate head and body portion, the head portion defining a breathing space in front of the wearer and the body portion defined a pressure space which is maintained under pressure by gas from a pressure gas source associated with the suit and which further includes a connection between the pressure space and the breathing space to permit air to flow from the pressure space into the breathing space during inhaling by the wearer.

A further object of the invention is to provide a method of operating a protective suit which comprises pressurizing a body portion of the suit so that it is maintained in a slightly inflated condition and directly a portion of the air from the pressure portion of the suit into a breathing space in a head portion in front of the wearer's face so that the wearer may inhale this air.

A further object of the invention is to provide a pressure gas ventilated pressure suit which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.

In the Drawings:

FIG. 1 is a schematic partial sectional view of a wearer having a protective suit constructed in accordance with the invention; and

FIG. 2 is an enlarged detailed view of another embodiment of a positive pressure demand valve for use with the suit shown in FIG. 1.

Referring to the drawings in particular, the invention embodied therein comprises a pressure gas ventilated pressure suit generally designated 1 adapted to cover a person or a wearer 50 and which includes a head portion generally designated 2 which defines a breathing space 18 in front of the face of the wearer and a body portion which defines a pressure space 4 separate from the breathing space and around the body of a wearer including a portion of the head portion in the embodiment shown. A connection 54 is provided between the pressure space 4 and the breathing space 18 and check valve means 3 are located in this connection which permits flow from the pressure space to the breathing space upon there being a predetermined pressure differential between these two spaces. This permits normal inhaling by the wearer from the air in the breathing space and drawing in of additional air from the pressure space. Air is exhaled from the breathing space through an exhaling valve 5.

The protective suit 1 used by the wearer 50 is provided with a full oxygen head mask 2. The full oxygen head mask 2 has breathing space 18 which is connected through an inhaling valve 3 with a pressure space or free space 4 remaining around the wearer's body of a body portion 52 of the suit 1. The valve 3 permits the withdrawal of inhaling air from the free space 4 into a breathing air space 18 in the head mask 2. The exhaled air is conducted from the wearer 50 to the outside over an exhaling valve 5, with which the full head mask 2 is likewise equipped. The wearer 50 carries respirator 6, a compressed air respirator, inside protective suit 1 on his back. The breathing air is conducted from a pressure reducer 7 and a hose line 8 with a coupling 9 to a pressure regulating valve 10 arranged in a wall of the suit 52. The pressure regulating valve 10 corresponds in its design to the known positive pressure demand valves of known respirator apparatus. An essential part is a diaphragm 11, which is loaded by a spring 12. Spring space 13 is in communication with the ambient atmosphere.

With compressed air tank 14 open, an excess pressure builds up in free space 4 which counterbalances the pressure of spring 12 on diaphragm 11, which can be adjusted through a spring cover 15. The control is effected by a control lever 16 of a compressed air valve 17 moved by diaphragm 11.

Inhaling valve 3 and exhaling valve 5 are together so spring-loaded that they counterbalance at least the excess pressure in the suit building up over pressure regulating valve 10. Preferably, however, exhaling valve 5 opens only at a pressure of 4 mbar in the free space 4. The higher pressure prevents flow-off losses when free space 4 is temporarily reduced in size by movement of the wearer. The inhaling volume is taken from free space 4 through the inhaling valve 3. The reduction of the excess pressure in the suit resulting from the withdrawal of breathing gas is compensated by the pressure regulating valve 10 supplied with air from compressed air tank 14. The expanding air is cool and has a corresponding refreshing effect in the interior of the suit.

During the following exhalation, inhaling valve 3 closes and the hot exhaled air is led off directly to the outside through exhaling valve 5. The increased opening pressure of exhaling valve 5 is hardly noticed by the wearer because the excess pressure in the suit propagates over the slightly spring loaded "(in direction of the arrow)" inhaling valve 3 practically into mask space 18 after the inhaling phase is completed. The wearer only has to overcome during the exhalation phase the pressure difference formed between the excess suit pressure in free space 4 and mask space 18.

With a greater spring load on inhaling valve 3, the excess suit pressure cannot propagate from free space 4 into mask air space 18. In this case a simple check valve suffices as an exhaling valve 5, so that the wearer does not have to overcome an additional exhaling resistance.

Spring cover 15, in addition to changing the force of spring 12, can also act as a switch with which the action of spring 12 on diaphragm 11 is cancelled. The excess pressure in free space 4 is thus completely eliminated. This is of advantage when putting on and taking off protective suit 1, when the wearer must pass through narrow cross sections. This is not possible with an inflated suit.

From pressure regulating valve 10, distributor lines 19 and 19' extend into the respective arms and legs of protective suit 1. The expanding air flows then from there over the entire body to inhaling valve 3, cooling it on its way.

FIG. 2 shows in a cuff 20 of the suit 1 the use of a normal positive pressure demand valve 21 instead of pressure regulating valve 10 (of FIG. 1). Valve 21 is mounted on the suit with a switching device 22 provided outside the suit. Mask connection 24 of positive pressure demand valve 21 extends in free space 4 of the suit. The connection of the hose line 8 from the pressure reducer 7 (which is shown in FIG. 1) is effected at the mask connection 24. The connection of distributor line 19 to the valve 21 is made at a mask connection 23. In this way, a positive pressure demand valve can be used instead of pressure regulating valve 10 for ventilating the suit and for keeping the pressure therein constant.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.