CA2079784C - A breathing system for smoke diving and the like - Google Patents
A breathing system for smoke diving and the likeInfo
- Publication number
- CA2079784C CA2079784C CA002079784A CA2079784A CA2079784C CA 2079784 C CA2079784 C CA 2079784C CA 002079784 A CA002079784 A CA 002079784A CA 2079784 A CA2079784 A CA 2079784A CA 2079784 C CA2079784 C CA 2079784C
- Authority
- CA
- Canada
- Prior art keywords
- breathing
- actuator
- valve
- bag
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
- B63C11/00—Equipment for dwelling or working underwater; Means for searching for underwater objects
- B63C11/02—Divers' equipment
- B63C11/18—Air supply
- B63C11/22—Air supply carried by diver
- B63C11/24—Air supply carried by diver in closed circulation
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B7/00—Respiratory apparatus
- A62B7/10—Respiratory apparatus with filter elements
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B9/00—Component parts for respiratory or breathing apparatus
- A62B9/02—Valves
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- Health & Medical Sciences (AREA)
- Pulmonology (AREA)
- General Health & Medical Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Respiratory Apparatuses And Protective Means (AREA)
Abstract
A closed or semi-closed breathing system for smoke diving and the like includes a pneumatically controlled breathing bag communicating in a circulation circuit with a breathing mouthpiece or breathing mask for a user, and with an absorption means for exhaled CO2, a pneumatic actuator arranged for alternating expansion and contraction of the breathing bag in accordance with the breathing pattern of the user, and a pressurized gas source coupled to the breathing bag to supplement the breathing gas therein. The system includes a mode regulator arranged to control the actuator's actuation of the breathing bag while simultaneously maintaining an overpressure in the breathing mask in relation to the surroundings, and a dosing means for the supply of a metered gas quantity to the breathing bag in dependence on its degree of filling.
Description
A BREATHING SYSTEM FOR SMORE DIVING AND THE LIKE
BACKGROUND OF THE lNv~ ION
The present invention relates to a closed or semi-closed breathing system for smoke diving and the like.
There are a number of known embodiments of self-contained breathing systems. Breathing equipment for smoke diving is designed for firefighting operations in which a firefighter dives into an environment containing smoke and toxic gas. Some smoke diving breathing systems in the prior art supply breathing gas through a breathing valve, and "dump"
exhaled gas directly to the surroundings through a one-way valve t"open breathing system"). Alternative types of breathing equipment are based on recovery of exhaled gas in a "closed" or "semi-closed" circulatory system. Exhaled gas is partly or completely purified of CO2 and supplied with oxygen so that it is again suitable as a breathing gas. With closed or semi-closed breathing systems, a long service life is achieved with a moderate gas supply, but they are normally difficult to breathe with because the gas is recirculated by lung force. In comparison, good open breathing systems are easy to breathe with, but have a considerably shorter service life since the weight of the apparatus must be kept low. A
substantial advantage with open breathing systems is that one is able to maintain a safety pressure (weak overpressure) in the breathing mask, so that the ingress of gases which are harmful to the user's health is prevented.
SUMMARY OF THE lNv~NlION
It is an object of the present invention to provide a closed or semi-closed breathing system which, in a preferred embodiment, has a safety overpressure in the breathing mask and utilizes the available breathing gas reservoir optimally.
The invention is also reliable in service, simple to produce, lightweight and has a long service life.
According to the present invention then, there is provided a breathing system, especially for use in an -atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled C02, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag, and to supply breathing gas to said breathing bag, by selectively supplying breathing gas from said pressurized gas source to said actuator, and by venting breathing gas from said actuator to said breathing bag, and dosing means for supplementing the breathing gas supplied to the breathing bag by said mode regulator, by supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag after a user exhalation.
In the present breathing system, a small breathing effort is required because the pressure of the supplied oxygen is used to assist the recirculation of the breathing gas.
Oxygen is supplied through the pneumatic actuator which alternatingly expands and contracts the breathing bag in accordance with the breathing pattern of the user. This is a technique which is already used in a semi-closed breathing system for underwater diving, and reference is made to US
patent No. 4,793,340. The technique has not however been previously used in a closed breathing system.
It is a important preferred feature of the invention that this technique is utilized to establish a "safety pressure" in the breathing mouthpiece or breathing mask of the user, as this prevents the ingress of gases which are harmful to the user's health. This is of great importance from a 207q784 safety point of view, and is, as far as applicant knows, not achieved in any other self-contained closed breathing system.
In the breathing system according to a preferred aspect of the invention, the mode regulator supplies the actuator with compressed oxygen, or alternatively "vents"
supplied oxygen to the breathing bag which thereby controls the recirculation of breathing gas. At the same time it ensures that a small safety overpressure is maintained in the breathing mask during inhalation as well as during exhalation.
The actuator is dimensioned so that the oxygen quantity received and thereafter "vented" to the breathing bag, is somewhat smaller than the quantity absorbed in the respiration. It is therefore necessary to inject a certain oxygen quantity directly into the circulation of the system, to maintain the oxygen level in the breathing gas. The invention achieves this because the dosing means is arranged to discharge a metered quantity of gas into the breathing bag each time when, during exhalation, there is insufficient filling of the breathing bag. Thus, the system is not, like many other closed oxygen apparatus, based on a fixed injection of gas rich in oxygen so it utilizes the available gas reservoir optimally. It has been found to be advantageous to dimension the system so that the maximum driving pressure of the actuator is approximately +/- 15 cm water column. In practice this implies that the actuator is able to compensate for the work which the lungs of the user otherwise would have to carry out in order to overcome restrictions through one-way valves, hoses C02 absorber, etc. in the system.
According to yet another aspect of the present invention, there is also provided a breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, the system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled CO2, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a m~
regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings, and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag, wherein said mode regulator comprises a valve arrangement and a sensing diaphragm cooperating therewith, said sensing diaphragm having first and second sides, said first side being influenced by the surrounding atmospheric pressure and by a spring mechanism for maintaining said overpressure in the breathing piece, said second side being influenced by the gas pressure in said breathing piece;
and movement of said sensing diaphragm from a central position is transferred to said valve arrangement which, in dependence on the movement direction of the diaphragm, either opens to supply pressurized gas to said actuator, or vents the actuator.
An advantageous embodiment of the system according to the invention is characterized in that the circulation circuit of the system includes conduit stretches of which the outer surfaces are covered by a relatively thick porous material which, saturated with water, utilizes the evaporation of the water for cooling down the breathing gas circulating in the circulation circuit during operation.
The breathing system is constructed in such a manner that surrounding gas flows past the surface and causes an efficient evaporation. The evaporation heat is partly taken from the wet surface of the conduit stretches which is cooled down considerably. Further, the wet surfaces of the conduit stretches and other cooled-down surfaces in the system have a good thermal conduction to internal surfaces of the breathing system, so that an efficient cooling of the breathing gas is achieved. Such an arrangement for cooling of the breathing gas is advantageous as compared to traditional breathing systems wherein the temperature of inhaled gas may be well above body temperature. In addition, this solution has the advantage that the evaporation increases with the surrounding temperature, so that the system manages to maintain an acceptable breathing gas temperature even in rather warm surroundings. Another advantage of this solution is that wetting with water is useful in a fire fighting environment.
The system is easily made ready for operation by, e.g. immersion in a container of water. A thick porous material will be able to absorb a considerable quantity of water, and the cooling therefore can take place over a relatively long time without another wetting of the porous material.
According to yet another aspect of the present invention, there is also provided a breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled C02, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a m~
regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative ~,~;
-to the surroundings, and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag, said actuator comprising a cylinder/piston unit coupled to said pressurized gas source through said mode regulator, said mode regulator including a valve arrangement comprising a first valve which is opened for venting said actuator, and a second valve which is opened to supply pressurized gas to the actuator.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described below in connection with an exemplary embodiment with reference to the drawings, wherein:
Fig. 1 shows a schematic view, partly in section, of a preferred embodiment of a breathing system according to the invention;
Fig. 2 shows a sectional view of the mode regulator in Fig. 1 on an enlarged scale, and Fig. 3 shows an enlarged sectional view of the breathing bag in Fig. 1, the Figure showing more detailed sectional views of the elements and units arranged within the breathing bag.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiment shown in Fig. 1 constitutes a closed breathing system wherein a breathing bag 1, a breathing mask 2 and a CO2 absorbing means are connected in series in a closed circulation circuit, said units being interconnected through conduit lengths or tubes 4, 5 and 6. The breathing gas is inhaled from breathing bag 1 through breathing mask 2 which is provided with one-way valves 7 and 8 ensuring that inhaled and exhaled gases are not mixed. Exhaled gas passes via means 3 which consists of a container containing a CO2 absorbing material, into breathing bag 1.
Within breathing bag 1 there is arranged a pneumatic actuator 9 consisting of a cylinder/piston unit (see Fig. 3) which, as shown, is articulated to the side walls of the ~h `
207q784 breathing bag in the central region thereof. The actuator causes alternating expansion and contraction of the breathing bag in accordance with the breathing pattern of the user, as further described below. For control of actuator 9, a mode regulator 10 supplies the actuator with compressed oxygen, or alternatively vents supplied oxygen to the breathing bag, as also further described below. Pressurized oxygen is supplied from a source 11 through a pressure reducing valve 12.
In the illustrated embodiment, actuator 9 is dimensioned such that the oxygen quantity which is received and thereafter vented to the breathing bag is somewhat smaller than the quantity absorbed in the user's respiration. In order to maintain the oxygen level in the breathing gas, it is therefore necessary to inject a certain oxygen quantity directly into the circulation circuit. For this purpose there is a dosing means 13 which discharges a metered oxygen quantity into breathing bag 1 each time when, during exhalation, there is insufficient filling of the breathing bag.
In order to determine the filling degree of the breathing bag in each exhalation (expansion of the breathing bag), there is provided a sensing means 14 in combination with a pair of arms 15, 16 following the movement of the breathing bag, the arms at one of their ends being pivotally connected to each other, and at their other ends being articulated to the side walls of the breathing bag at the same places where actuator 9 is coupled to the breathing bag. The sensing means comprises a holding member 17 fixed to one arm 15 and extending in the direction of and past the other arm 16, a lever 18 pivotally connected to the free end of the holding member, a transverse pin 19 fixed to the arm 16 and cooperating with lever 18, and a valve 20 (see Fig. 3) provided in the holding member and arranged to be actuated by lever 18. This valve is opened when lever 18 is lifted by transverse pin 19 when breathing bag 1 is filled beyond a certain degree. A "blocking signal" is then delivered to dosing means 13, as further described below.
As appears from Fig. 1, the outer surfaces of conduit lengths 4, 5, 6 are covered by a relatively thick layer of a material 21 which is porous and water-absorbing, and which, in operation, is intended to be saturated with water. The water evaporates and cools-down the breathing gas in the circulation circuit. Container 3 is also covered by the water-absorbing material, and those parts of the circulation circuit located downstream of container 3, may be extended in a suitable manner to achieve a large, efficient evaporation surface to the surrounding atmosphere.
The construction of mode regulator 10 is shown in more detail in Fig. 2. It consists of a housing 22 containing a sensing diaphragm 23 dividing the housing into a pair of chambers 24, 25. Chamber 24 communicates with the outer atmosphere through a pair of apertures 26, 27. Chamber 25 communicates with breathing mask 2 through conduit 4 and is supplied with breathing gas from breathing bag 1 through a one-way valve 28. In chamber 24 there is a spring 29 which acts upon sensing diaphragm 23, so that it is affected by a spring force in addition to the atmosphere pressure in chamber 24. In this manner there is an overpressure or safety pressure achieved in the system when the spring is activated.
Spring 29 is arranged in a cap 30 which is screwed into housing 22 and can be screwed in to a greater or lesser extent, for setting of a desired spring prestressing force and thereby a desired overpressure. It is obvious that the diaphragm-influencing means may be carried out in many other ways than the illustrated spring and cap, but it is essential that the means is easily accessible to the user.
Sensing diaphragm 23 is mechanically coupled to a lever 31 for alternative actuation of a first and a second valve 32 and 33. First valve 32 communicates with actuator 9 through a conduit 34, and second valve 33 is coupled to a ' -207~784 conduit 35 communicating with pressurized gas source 11 (through reducing valve 12) as well as with actuator 9, as shown in Fig. 3.
! The construction of actuator 9 and dosing means 13 is shown in more detail in Fig. 3.
As shown, actuator 9 consists of a cylinder 36 and a piston 37 having, as viewed in Fig. 3, an upper pressure surface 37a which is substantially smaller than the lower pressure surface 37b of the piston. The upper cylinder compartment 36a is connected to pressurized gas source 11 through a conduit 38, and the lower cylinder compartment 36b is connected to valves 32, 33 of the mode regulator through a conduit 39 (passing through dosing means 13) and conduit 34.
Thus, the smallest pressure surface 37a of the piston stands under a constant pressure influence from pressurized gas source 11, so that the pressure direction of actuator 9 changes as its lower cylinder compartment 36b is supplied with gas from the pressurized gas source (through mode regulator valve 33) or is vented (through valve 32). As an alternative to connecting the pressurized gas source to the upper cylinder compartment, the upper side of the piston instead might be acted upon by a continuous spring force.
Dosing means 13 includes a small gas reservoir 40 which is filled with oxygen through a first valve or inlet valve 41 which is connected to pressurized gas source 11 through conduit 42 and conduit 38. Dosing means 13 discharges into the breathing bag through a second valve or outlet valve 43. Valves 41 and 43 are arranged to be opened and closed alternatively by an operating means in the form of a spring-loaded lever 44 which, in its initial position, keeps valve41 open. There is a unit connected in the conduit 39 between valves 32, 33 of mode regulator 10 and the lower cylinder compartment of actuator 9. This unit consists of a pair of spring-loaded and oppositely directed one-way valves 45, 46 connected in parallel, and a chamber 47 connected in parallel -to the valves and which is divided in two parts by a control diaphragm 48 as shown in Fig. 3.
When gas is flowing through one of one-way valves 45, 46 in the conduit 39, the pressure drop across the one-way valve concerned causes diaphragm 48 to be pressed in the flow direction of the gas. This is utilized to control dosing means 13, so that it discharges the gas in the reservoir 40 into breathing bag 1 (through the valve 43) each time when, during exhalation, there is insufficient filling of the breathing bag.
For this purpose control diaphragm 48 is coupled to an operating rod 49 which is moved to the right and affects lever 44 when diaphragm 48 is pressed to the right and opens valve 43. This will occur provided that the movement of lS operating rod 49 is not prevented by a 'blocking signal"
delivered from sensing means 14. As mentioned above, this blocking signal is provided from valve 20. This is connected to pressurized gas source 11 through a conduit 50, upper cylinder compartment 36a of actuator cylinder 36 and conduit 38. It is further connected through a conduit S1 to a cylinder/piston unit 52 arranged in dosing means 13 and having a spring-loaded blocking piston 53 and an associated venting valve 54. The blocking signal occurs when blocking piston 53 is pressure-actuated by opening of valve 20 so that the piston is moved to the left and actuates a blocking lever 55 preventing said movement of operating rod 49 even if control diaphragm 48 is pressed to the right. The blocking signal is nullified and reset when control diaphragm 48 is pressed to the left, so that blocking lever 55 is pivoted by actuation from operating rod 49 and opens venting valve 54, so that blocking piston 53 is returned to its initial position by spring influence.
The operation of the breathing system will be further described below.
As soon as the user of the system starts inhalation, .~
the pressure in chamber 25 of mode regulator 10 falls so that sensing diaphragm 23 is pressed towards the chamber and opens valve 32. Venting of gas from lower cylinder compartment 36b of the actuator 9 starts, so that the actuator contracts the side faces of breathing bag 1 and maintains a safety overpressure in breathing mask 2. With exhalation the pressure in the breathing mask rises, and this pressure increase is transferred through a passage 56 to chamber 25 of the mode regulator, so that sensing diaphragm 23 is pressed outwards towards chamber 24. Thereby valve 33 is opened, so that the lower cylinder compartment of actuator 9 is supplied with compressed gas (oxygen) from the pressurized gas source.
The main supply of oxygen to the breathing bag takes place through venting valve 32 of the mode regulator. Since the actuator is dimensioned to supply only part of the necessary oxygen, dosing means 13 injects the metered oxygen quantity from reservoir 40 to breathing bag 1 after each exhalation when the breathing bag is insufficiently filled with breathing gas. The injection of oxygen takes place at the same time as oxygen is vented from the actuator. Control diaphragm 48 is pressed to the right and opens valve 43 by way of operating rod 49 and lever 44 ~ust after the inhalation phase has started. Valve 43 will only open if sensing means 14 has not delivered a "blocking signal", which signal is delivered from valve 20 when lever 18 is lifted by transverse pin 19 on arm 16. As mentioned above, the blocking signal disables control diaphragm 48 from moving the lever 44 to the right and opening valve 43. The blocking signal is nullified and reset automatically when the breathing bag again gets into the exhalation mode and diaphragm 48 is pressed to the left and opens venting valve 54.
In the embodiment described above it has been emphasized that the equipment is to be completely "closed", since this gives advantages with respect to safety in inflammable surroundings. In principle, there is nothing to ., prevent the equipment from being made "semi-closed", for example with a view to sports diving. In that case the oxygen supply through the pneumatic actuator is larger than the consumption, and an automatic means may be constructed which dumps gas each time the breathing bag in exhalation is filled beyond a given level. Further, it is conceivable that the pneumatic assistance could be based on gas supply from one gas reservoir, and that the compensation of oxygen could take place from another one, without changing the structure to a substantial degree.
In cases where the system according to the invention is to be used in a gas filled atmosphere, it is natural, because of weight, size, etc., to build the mode regulator into the breathing bag, as shown and described. In connection with e.g. diving, hydrostatic conditions will make it natural to build the mode regulator into the breathing mouthpiece or breathing mask. The breathing system will be operative as soon as the reducing valve supplies gas to the pneumatics of the system.
It is clear that the arrangement for cooling-down of the breathing gas may be applied for virtually all types of breathing systems used in gas-filled surroundings.
~
BACKGROUND OF THE lNv~ ION
The present invention relates to a closed or semi-closed breathing system for smoke diving and the like.
There are a number of known embodiments of self-contained breathing systems. Breathing equipment for smoke diving is designed for firefighting operations in which a firefighter dives into an environment containing smoke and toxic gas. Some smoke diving breathing systems in the prior art supply breathing gas through a breathing valve, and "dump"
exhaled gas directly to the surroundings through a one-way valve t"open breathing system"). Alternative types of breathing equipment are based on recovery of exhaled gas in a "closed" or "semi-closed" circulatory system. Exhaled gas is partly or completely purified of CO2 and supplied with oxygen so that it is again suitable as a breathing gas. With closed or semi-closed breathing systems, a long service life is achieved with a moderate gas supply, but they are normally difficult to breathe with because the gas is recirculated by lung force. In comparison, good open breathing systems are easy to breathe with, but have a considerably shorter service life since the weight of the apparatus must be kept low. A
substantial advantage with open breathing systems is that one is able to maintain a safety pressure (weak overpressure) in the breathing mask, so that the ingress of gases which are harmful to the user's health is prevented.
SUMMARY OF THE lNv~NlION
It is an object of the present invention to provide a closed or semi-closed breathing system which, in a preferred embodiment, has a safety overpressure in the breathing mask and utilizes the available breathing gas reservoir optimally.
The invention is also reliable in service, simple to produce, lightweight and has a long service life.
According to the present invention then, there is provided a breathing system, especially for use in an -atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled C02, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag, and to supply breathing gas to said breathing bag, by selectively supplying breathing gas from said pressurized gas source to said actuator, and by venting breathing gas from said actuator to said breathing bag, and dosing means for supplementing the breathing gas supplied to the breathing bag by said mode regulator, by supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag after a user exhalation.
In the present breathing system, a small breathing effort is required because the pressure of the supplied oxygen is used to assist the recirculation of the breathing gas.
Oxygen is supplied through the pneumatic actuator which alternatingly expands and contracts the breathing bag in accordance with the breathing pattern of the user. This is a technique which is already used in a semi-closed breathing system for underwater diving, and reference is made to US
patent No. 4,793,340. The technique has not however been previously used in a closed breathing system.
It is a important preferred feature of the invention that this technique is utilized to establish a "safety pressure" in the breathing mouthpiece or breathing mask of the user, as this prevents the ingress of gases which are harmful to the user's health. This is of great importance from a 207q784 safety point of view, and is, as far as applicant knows, not achieved in any other self-contained closed breathing system.
In the breathing system according to a preferred aspect of the invention, the mode regulator supplies the actuator with compressed oxygen, or alternatively "vents"
supplied oxygen to the breathing bag which thereby controls the recirculation of breathing gas. At the same time it ensures that a small safety overpressure is maintained in the breathing mask during inhalation as well as during exhalation.
The actuator is dimensioned so that the oxygen quantity received and thereafter "vented" to the breathing bag, is somewhat smaller than the quantity absorbed in the respiration. It is therefore necessary to inject a certain oxygen quantity directly into the circulation of the system, to maintain the oxygen level in the breathing gas. The invention achieves this because the dosing means is arranged to discharge a metered quantity of gas into the breathing bag each time when, during exhalation, there is insufficient filling of the breathing bag. Thus, the system is not, like many other closed oxygen apparatus, based on a fixed injection of gas rich in oxygen so it utilizes the available gas reservoir optimally. It has been found to be advantageous to dimension the system so that the maximum driving pressure of the actuator is approximately +/- 15 cm water column. In practice this implies that the actuator is able to compensate for the work which the lungs of the user otherwise would have to carry out in order to overcome restrictions through one-way valves, hoses C02 absorber, etc. in the system.
According to yet another aspect of the present invention, there is also provided a breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, the system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled CO2, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a m~
regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings, and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag, wherein said mode regulator comprises a valve arrangement and a sensing diaphragm cooperating therewith, said sensing diaphragm having first and second sides, said first side being influenced by the surrounding atmospheric pressure and by a spring mechanism for maintaining said overpressure in the breathing piece, said second side being influenced by the gas pressure in said breathing piece;
and movement of said sensing diaphragm from a central position is transferred to said valve arrangement which, in dependence on the movement direction of the diaphragm, either opens to supply pressurized gas to said actuator, or vents the actuator.
An advantageous embodiment of the system according to the invention is characterized in that the circulation circuit of the system includes conduit stretches of which the outer surfaces are covered by a relatively thick porous material which, saturated with water, utilizes the evaporation of the water for cooling down the breathing gas circulating in the circulation circuit during operation.
The breathing system is constructed in such a manner that surrounding gas flows past the surface and causes an efficient evaporation. The evaporation heat is partly taken from the wet surface of the conduit stretches which is cooled down considerably. Further, the wet surfaces of the conduit stretches and other cooled-down surfaces in the system have a good thermal conduction to internal surfaces of the breathing system, so that an efficient cooling of the breathing gas is achieved. Such an arrangement for cooling of the breathing gas is advantageous as compared to traditional breathing systems wherein the temperature of inhaled gas may be well above body temperature. In addition, this solution has the advantage that the evaporation increases with the surrounding temperature, so that the system manages to maintain an acceptable breathing gas temperature even in rather warm surroundings. Another advantage of this solution is that wetting with water is useful in a fire fighting environment.
The system is easily made ready for operation by, e.g. immersion in a container of water. A thick porous material will be able to absorb a considerable quantity of water, and the cooling therefore can take place over a relatively long time without another wetting of the porous material.
According to yet another aspect of the present invention, there is also provided a breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising a circulation circuit, a breathing piece for application to the face of a user, absorption means for absorbing exhaled C02, a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means, a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user, a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein, a m~
regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative ~,~;
-to the surroundings, and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag, said actuator comprising a cylinder/piston unit coupled to said pressurized gas source through said mode regulator, said mode regulator including a valve arrangement comprising a first valve which is opened for venting said actuator, and a second valve which is opened to supply pressurized gas to the actuator.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described below in connection with an exemplary embodiment with reference to the drawings, wherein:
Fig. 1 shows a schematic view, partly in section, of a preferred embodiment of a breathing system according to the invention;
Fig. 2 shows a sectional view of the mode regulator in Fig. 1 on an enlarged scale, and Fig. 3 shows an enlarged sectional view of the breathing bag in Fig. 1, the Figure showing more detailed sectional views of the elements and units arranged within the breathing bag.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiment shown in Fig. 1 constitutes a closed breathing system wherein a breathing bag 1, a breathing mask 2 and a CO2 absorbing means are connected in series in a closed circulation circuit, said units being interconnected through conduit lengths or tubes 4, 5 and 6. The breathing gas is inhaled from breathing bag 1 through breathing mask 2 which is provided with one-way valves 7 and 8 ensuring that inhaled and exhaled gases are not mixed. Exhaled gas passes via means 3 which consists of a container containing a CO2 absorbing material, into breathing bag 1.
Within breathing bag 1 there is arranged a pneumatic actuator 9 consisting of a cylinder/piston unit (see Fig. 3) which, as shown, is articulated to the side walls of the ~h `
207q784 breathing bag in the central region thereof. The actuator causes alternating expansion and contraction of the breathing bag in accordance with the breathing pattern of the user, as further described below. For control of actuator 9, a mode regulator 10 supplies the actuator with compressed oxygen, or alternatively vents supplied oxygen to the breathing bag, as also further described below. Pressurized oxygen is supplied from a source 11 through a pressure reducing valve 12.
In the illustrated embodiment, actuator 9 is dimensioned such that the oxygen quantity which is received and thereafter vented to the breathing bag is somewhat smaller than the quantity absorbed in the user's respiration. In order to maintain the oxygen level in the breathing gas, it is therefore necessary to inject a certain oxygen quantity directly into the circulation circuit. For this purpose there is a dosing means 13 which discharges a metered oxygen quantity into breathing bag 1 each time when, during exhalation, there is insufficient filling of the breathing bag.
In order to determine the filling degree of the breathing bag in each exhalation (expansion of the breathing bag), there is provided a sensing means 14 in combination with a pair of arms 15, 16 following the movement of the breathing bag, the arms at one of their ends being pivotally connected to each other, and at their other ends being articulated to the side walls of the breathing bag at the same places where actuator 9 is coupled to the breathing bag. The sensing means comprises a holding member 17 fixed to one arm 15 and extending in the direction of and past the other arm 16, a lever 18 pivotally connected to the free end of the holding member, a transverse pin 19 fixed to the arm 16 and cooperating with lever 18, and a valve 20 (see Fig. 3) provided in the holding member and arranged to be actuated by lever 18. This valve is opened when lever 18 is lifted by transverse pin 19 when breathing bag 1 is filled beyond a certain degree. A "blocking signal" is then delivered to dosing means 13, as further described below.
As appears from Fig. 1, the outer surfaces of conduit lengths 4, 5, 6 are covered by a relatively thick layer of a material 21 which is porous and water-absorbing, and which, in operation, is intended to be saturated with water. The water evaporates and cools-down the breathing gas in the circulation circuit. Container 3 is also covered by the water-absorbing material, and those parts of the circulation circuit located downstream of container 3, may be extended in a suitable manner to achieve a large, efficient evaporation surface to the surrounding atmosphere.
The construction of mode regulator 10 is shown in more detail in Fig. 2. It consists of a housing 22 containing a sensing diaphragm 23 dividing the housing into a pair of chambers 24, 25. Chamber 24 communicates with the outer atmosphere through a pair of apertures 26, 27. Chamber 25 communicates with breathing mask 2 through conduit 4 and is supplied with breathing gas from breathing bag 1 through a one-way valve 28. In chamber 24 there is a spring 29 which acts upon sensing diaphragm 23, so that it is affected by a spring force in addition to the atmosphere pressure in chamber 24. In this manner there is an overpressure or safety pressure achieved in the system when the spring is activated.
Spring 29 is arranged in a cap 30 which is screwed into housing 22 and can be screwed in to a greater or lesser extent, for setting of a desired spring prestressing force and thereby a desired overpressure. It is obvious that the diaphragm-influencing means may be carried out in many other ways than the illustrated spring and cap, but it is essential that the means is easily accessible to the user.
Sensing diaphragm 23 is mechanically coupled to a lever 31 for alternative actuation of a first and a second valve 32 and 33. First valve 32 communicates with actuator 9 through a conduit 34, and second valve 33 is coupled to a ' -207~784 conduit 35 communicating with pressurized gas source 11 (through reducing valve 12) as well as with actuator 9, as shown in Fig. 3.
! The construction of actuator 9 and dosing means 13 is shown in more detail in Fig. 3.
As shown, actuator 9 consists of a cylinder 36 and a piston 37 having, as viewed in Fig. 3, an upper pressure surface 37a which is substantially smaller than the lower pressure surface 37b of the piston. The upper cylinder compartment 36a is connected to pressurized gas source 11 through a conduit 38, and the lower cylinder compartment 36b is connected to valves 32, 33 of the mode regulator through a conduit 39 (passing through dosing means 13) and conduit 34.
Thus, the smallest pressure surface 37a of the piston stands under a constant pressure influence from pressurized gas source 11, so that the pressure direction of actuator 9 changes as its lower cylinder compartment 36b is supplied with gas from the pressurized gas source (through mode regulator valve 33) or is vented (through valve 32). As an alternative to connecting the pressurized gas source to the upper cylinder compartment, the upper side of the piston instead might be acted upon by a continuous spring force.
Dosing means 13 includes a small gas reservoir 40 which is filled with oxygen through a first valve or inlet valve 41 which is connected to pressurized gas source 11 through conduit 42 and conduit 38. Dosing means 13 discharges into the breathing bag through a second valve or outlet valve 43. Valves 41 and 43 are arranged to be opened and closed alternatively by an operating means in the form of a spring-loaded lever 44 which, in its initial position, keeps valve41 open. There is a unit connected in the conduit 39 between valves 32, 33 of mode regulator 10 and the lower cylinder compartment of actuator 9. This unit consists of a pair of spring-loaded and oppositely directed one-way valves 45, 46 connected in parallel, and a chamber 47 connected in parallel -to the valves and which is divided in two parts by a control diaphragm 48 as shown in Fig. 3.
When gas is flowing through one of one-way valves 45, 46 in the conduit 39, the pressure drop across the one-way valve concerned causes diaphragm 48 to be pressed in the flow direction of the gas. This is utilized to control dosing means 13, so that it discharges the gas in the reservoir 40 into breathing bag 1 (through the valve 43) each time when, during exhalation, there is insufficient filling of the breathing bag.
For this purpose control diaphragm 48 is coupled to an operating rod 49 which is moved to the right and affects lever 44 when diaphragm 48 is pressed to the right and opens valve 43. This will occur provided that the movement of lS operating rod 49 is not prevented by a 'blocking signal"
delivered from sensing means 14. As mentioned above, this blocking signal is provided from valve 20. This is connected to pressurized gas source 11 through a conduit 50, upper cylinder compartment 36a of actuator cylinder 36 and conduit 38. It is further connected through a conduit S1 to a cylinder/piston unit 52 arranged in dosing means 13 and having a spring-loaded blocking piston 53 and an associated venting valve 54. The blocking signal occurs when blocking piston 53 is pressure-actuated by opening of valve 20 so that the piston is moved to the left and actuates a blocking lever 55 preventing said movement of operating rod 49 even if control diaphragm 48 is pressed to the right. The blocking signal is nullified and reset when control diaphragm 48 is pressed to the left, so that blocking lever 55 is pivoted by actuation from operating rod 49 and opens venting valve 54, so that blocking piston 53 is returned to its initial position by spring influence.
The operation of the breathing system will be further described below.
As soon as the user of the system starts inhalation, .~
the pressure in chamber 25 of mode regulator 10 falls so that sensing diaphragm 23 is pressed towards the chamber and opens valve 32. Venting of gas from lower cylinder compartment 36b of the actuator 9 starts, so that the actuator contracts the side faces of breathing bag 1 and maintains a safety overpressure in breathing mask 2. With exhalation the pressure in the breathing mask rises, and this pressure increase is transferred through a passage 56 to chamber 25 of the mode regulator, so that sensing diaphragm 23 is pressed outwards towards chamber 24. Thereby valve 33 is opened, so that the lower cylinder compartment of actuator 9 is supplied with compressed gas (oxygen) from the pressurized gas source.
The main supply of oxygen to the breathing bag takes place through venting valve 32 of the mode regulator. Since the actuator is dimensioned to supply only part of the necessary oxygen, dosing means 13 injects the metered oxygen quantity from reservoir 40 to breathing bag 1 after each exhalation when the breathing bag is insufficiently filled with breathing gas. The injection of oxygen takes place at the same time as oxygen is vented from the actuator. Control diaphragm 48 is pressed to the right and opens valve 43 by way of operating rod 49 and lever 44 ~ust after the inhalation phase has started. Valve 43 will only open if sensing means 14 has not delivered a "blocking signal", which signal is delivered from valve 20 when lever 18 is lifted by transverse pin 19 on arm 16. As mentioned above, the blocking signal disables control diaphragm 48 from moving the lever 44 to the right and opening valve 43. The blocking signal is nullified and reset automatically when the breathing bag again gets into the exhalation mode and diaphragm 48 is pressed to the left and opens venting valve 54.
In the embodiment described above it has been emphasized that the equipment is to be completely "closed", since this gives advantages with respect to safety in inflammable surroundings. In principle, there is nothing to ., prevent the equipment from being made "semi-closed", for example with a view to sports diving. In that case the oxygen supply through the pneumatic actuator is larger than the consumption, and an automatic means may be constructed which dumps gas each time the breathing bag in exhalation is filled beyond a given level. Further, it is conceivable that the pneumatic assistance could be based on gas supply from one gas reservoir, and that the compensation of oxygen could take place from another one, without changing the structure to a substantial degree.
In cases where the system according to the invention is to be used in a gas filled atmosphere, it is natural, because of weight, size, etc., to build the mode regulator into the breathing bag, as shown and described. In connection with e.g. diving, hydrostatic conditions will make it natural to build the mode regulator into the breathing mouthpiece or breathing mask. The breathing system will be operative as soon as the reducing valve supplies gas to the pneumatics of the system.
It is clear that the arrangement for cooling-down of the breathing gas may be applied for virtually all types of breathing systems used in gas-filled surroundings.
~
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising:
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag, and to supply breathing gas to said breathing bag, by selectively supplying breathing gas from said pressurized gas source to said actuator, and by venting breathing gas from said actuator to said breathing bag; and dosing means for supplementing the breathing gas supplied to the breathing bag by said mode regulator, by supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag after a user exhalation.
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag, and to supply breathing gas to said breathing bag, by selectively supplying breathing gas from said pressurized gas source to said actuator, and by venting breathing gas from said actuator to said breathing bag; and dosing means for supplementing the breathing gas supplied to the breathing bag by said mode regulator, by supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag after a user exhalation.
2. A breathing system according to claim 1, wherein said circulation circuit comprises lengths of conduit covered by a relatively thick porous material which, when saturated with water, utilizes the evaporation of the water for cooling down the breathing gas circulating in the circulation circuit during operation.
3. A breathing system according to claim 2, wherein said mode regulator comprises a valve arrangement and a sensing diaphragm cooperating therewith, said sensing diaphragm having first and second sides, said first side being influenced by the surrounding atmospheric pressure, said second side being influenced by the gas pressure in said breathing piece; and movement of said sensing diaphragm from a central position is transferred to said valve arrangement which, in dependence on the movement direction of the diaphragm, either opens to supply pressurized gas to said actuator, or vents the actuator.
4. A breathing system according to claim 1, wherein said actuator comprises a cylinder/piston unit coupled to said pressurized gas source through said mode regulator, said mode regulator including a valve arrangement comprising a first valve which is opened for venting of said actuator, and a second valve which is opened to supply pressurized gas to the actuator.
5. A breathing system according to claim 4, wherein the piston of said actuator has opposite pressure surfaces with substantially different areas, the smallest pressure surface being under constant pressure influence from said pressurized gas source, so that a pressure direction of said actuator changes as the opposite surface of said piston is supplied with gas from the pressurized gas source or is vented.
6. A breathing system according to claim 3, wherein the spring force of said spring means is adjustable, for adjustment of the overpressure in the breathing piece.
7. A breathing system according to claim 4, wherein said dosing means comprises a gas reservoir which is connected to said pressurized gas source through a third valve and to the interior of said breathing bag through a fourth valve, said third and fourth valves being arranged to be actuated by a common operating member, and wherein a control diaphragm is arranged in a conduit connection between said valve arrangement of said mode regulator, and said actuator, said diaphragm being coupled to said operating member and serving to open said fourth valve during venting of the actuator through said first valve.
8. A breathing system according to claim 7, including a sensing means for sensing whether there is sufficient gas in the breathing system, and which, in case a chosen degree of filling of said breathing bag is exceeded, is arranged to actuate a blocking means for then preventing said common operating member of said dosing means from opening said fourth valve.
9. A breathing system according to claim 8, wherein said sensing means comprises a fifth valve and said blocking means comprises a pneumatic piston coupled to said pressurized gas source through said fifth valve.
10. A breathing system according to claim 3, wherein said first side of the sensing diaphragm is also influenced by a spring mechanism for maintaining an overpressure in said breathing piece relative to the surroundings.
11. A breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising:
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings; and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag;
wherein:
said mode regulator comprises a valve arrangement and a sensing diaphragm cooperating therewith, said sensing diaphragm having first and second sides, said first side being influenced by the surrounding atmospheric pressure and by a spring mechanism for maintaining said overpressure in the breathing piece, said second side being influenced by the gas pressure in said breathing piece; and movement of said sensing diaphragm from a central position is transferred to said valve arrangement which, in dependence on the movement direction of the diaphragm, either opens to supply pressurized gas to said actuator, or vents the actuator.
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings; and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag;
wherein:
said mode regulator comprises a valve arrangement and a sensing diaphragm cooperating therewith, said sensing diaphragm having first and second sides, said first side being influenced by the surrounding atmospheric pressure and by a spring mechanism for maintaining said overpressure in the breathing piece, said second side being influenced by the gas pressure in said breathing piece; and movement of said sensing diaphragm from a central position is transferred to said valve arrangement which, in dependence on the movement direction of the diaphragm, either opens to supply pressurized gas to said actuator, or vents the actuator.
12. A breathing system according to claim 11, wherein the spring force of said spring mechanism is adjustable, for adjustment of the overpressure in the breathing piece.
13. A breathing system, especially for use in an atmosphere containing toxic gases, wherein exhaled gas is at least partly recirculated, said system comprising:
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings; and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag;
said actuator comprising a cylinder/piston unit coupled to said pressurized gas source through said mode regulator, said mode regulator including a valve arrangement comprising a first valve which is opened for venting said actuator, and a second valve which is opened to supply pressurized gas to the actuator.
a circulation circuit;
a breathing piece for application to the face of a user;
absorption means for absorbing exhaled CO2;
a pneumatically controlled breathing bag communicating in said circulation circuit with said breathing piece and said absorption means;
a pneumatic actuator arranged for alternating expansion and contraction of said breathing bag in accordance with the breathing pattern of the user;
a pressurized gas source coupled to said breathing bag to supplement the breathing gas therein;
a mode regulator arranged to control the actuator's expansion and contraction of the breathing bag while simultaneously maintaining an overpressure in said breathing piece, relative to the surroundings; and dosing means for supplying a metered gas quantity to said breathing bag in dependence on the degree of filling of the bag;
said actuator comprising a cylinder/piston unit coupled to said pressurized gas source through said mode regulator, said mode regulator including a valve arrangement comprising a first valve which is opened for venting said actuator, and a second valve which is opened to supply pressurized gas to the actuator.
14. A breathing system according to claim 13, wherein the piston of the actuator has opposite pressure surfaces with substantially different areas, the smallest pressure surface being under constant pressure influence from said pressurized gas source, so that a pressure direction of said actuator changes as the opposite surface of said piston is supplied with gas from the pressurized gas source or is vented.
15. A breathing system according to claim 13, wherein said dosing means comprises a gas reservoir which is connected to said pressurized gas source through a third valve and to the interior of said breathing bag through a fourth valve, said third and fourth valves being arranged to be actuated by a common operating member, and wherein a control diaphragm is arranged in a conduit connection between said valve arrangement of said mode regulator, and said actuator, said diaphragm being coupled to said operating member and serving to open said fourth valve during venting of the actuator through said first valve.
16. A breathing system according to claim 15, including a sensing means for sensing whether there is sufficient gas in the breathing system in which, in case a chosen degree of filling of said breathing bag is exceeded, is arranged to actuate blocking means for preventing said common operating member of said dosing means from opening said fourth valve.
17. A breathing system according to claim 16, wherein said sensing means comprises a fifth valve and said blocking means comprises a pneumatic piston coupled to said pressurized gas source through said fifth valve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO901521A NO174836C (en) | 1990-04-03 | 1990-04-03 | Breathing system for smoke diving and the like. |
| NO901521 | 1990-04-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2079784C true CA2079784C (en) | 1996-01-09 |
Family
ID=19893049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002079784A Expired - Lifetime CA2079784C (en) | 1990-04-03 | 1991-04-02 | A breathing system for smoke diving and the like |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0524966B1 (en) |
| JP (1) | JP3098538B2 (en) |
| AT (1) | ATE157889T1 (en) |
| AU (1) | AU651968B2 (en) |
| BR (1) | BR9106307A (en) |
| CA (1) | CA2079784C (en) |
| DE (1) | DE69127621T2 (en) |
| ES (1) | ES2109265T3 (en) |
| NO (1) | NO174836C (en) |
| WO (1) | WO1991015265A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2357979B (en) * | 1999-12-07 | 2004-02-18 | Edward Cumming | Breathing apparatus |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE928810C (en) * | 1948-10-19 | 1955-06-10 | Carl Von Hoff | Automatic control of a nutrient gas supply, especially for oxygen breathing apparatus |
| DE3105637C2 (en) * | 1981-02-17 | 1986-09-18 | Interspiro GmbH, 7529 Forst | Circulatory breathing apparatus |
| CA1184472A (en) * | 1982-02-16 | 1985-03-26 | Les Suchy | Breathing protective apparatus |
| US4793340A (en) * | 1985-09-18 | 1988-12-27 | Den Norske Stats Oljeselskap A.S. | Breathing system for divers |
| DE3930362A1 (en) * | 1989-09-12 | 1991-03-21 | Draegerwerk Ag | CIRCUIT BREATH PROTECTOR |
-
1990
- 1990-04-03 NO NO901521A patent/NO174836C/en not_active IP Right Cessation
-
1991
- 1991-04-02 AT AT91906624T patent/ATE157889T1/en not_active IP Right Cessation
- 1991-04-02 DE DE69127621T patent/DE69127621T2/en not_active Expired - Lifetime
- 1991-04-02 EP EP91906624A patent/EP0524966B1/en not_active Expired - Lifetime
- 1991-04-02 AU AU75724/91A patent/AU651968B2/en not_active Expired
- 1991-04-02 WO PCT/NO1991/000052 patent/WO1991015265A1/en active IP Right Grant
- 1991-04-02 BR BR919106307A patent/BR9106307A/en not_active IP Right Cessation
- 1991-04-02 CA CA002079784A patent/CA2079784C/en not_active Expired - Lifetime
- 1991-04-02 ES ES91906624T patent/ES2109265T3/en not_active Expired - Lifetime
- 1991-04-02 JP JP03507035A patent/JP3098538B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ES2109265T3 (en) | 1998-01-16 |
| NO174836C (en) | 1994-07-20 |
| EP0524966B1 (en) | 1997-09-10 |
| JPH05505951A (en) | 1993-09-02 |
| NO901521D0 (en) | 1990-04-03 |
| NO901521L (en) | 1991-10-04 |
| NO174836B (en) | 1994-04-11 |
| DE69127621D1 (en) | 1997-10-16 |
| EP0524966A1 (en) | 1993-02-03 |
| ATE157889T1 (en) | 1997-09-15 |
| AU651968B2 (en) | 1994-08-11 |
| AU7572491A (en) | 1991-10-30 |
| WO1991015265A1 (en) | 1991-10-17 |
| BR9106307A (en) | 1993-04-13 |
| JP3098538B2 (en) | 2000-10-16 |
| DE69127621T2 (en) | 1998-04-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |