MICRO FLOW REGULATOR AND BREATHING HOOD SYSTEM USING SAME

Abstract

A breathing apparatus provides gas within a hood surrounding a user's head from two oxygen tanks which each utilize a regulator. The first tank serves to inflate the hood while the second provides oxygen to the hood at a sufficient amount for human breathing for a longer time than traditionally available for such hoods. The longer life is provided through the use of micro regulators which utilize micro springs or wave washers and micro machining techniques to regulate the flow of oxygen in a way that has not been previously possible.

Claims

1. A breathing apparatus for providing a user with a breathable atmosphere, such breathable atmosphere being generally isolated from a potentially hazardous external environment, said apparatus comprising: a hood capable of surrounding a user's head, said hood having an internal volume therein; a first oxygen source including a first amount of pressurized oxygen to said hood via a first regulator, said first regulator providing a first rate of said first amount of oxygen; and a second oxygen source including a second amount of pressurized oxygen to said hood via a second regulator, said second regulator providing a second rate of said second amount of oxygen; wherein, said first rate is greater than said second rate; wherein, said first amount of oxygen is depleted before said second amount of oxygen; and wherein, said second rate supplies sufficient oxygen from said first tank to allow a human to breathe from said hood for at least 600 seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 provides a basic perspective view of an embodiment of a personal breathing equipment (PBE) suitable for use on an aircraft,

[0023] FIG. 2 provides a side cutaway view of an embodiment of a microregulator using a micro compression spring.

[0024] FIG. 3 provides a side cutaway view of an embodiment of a microregulator using a wave washer array.

[0025] FIG. 4 provides an indication of outlet versus inlet pressure for the regulator of FIG. 2.

[0026] FIG. 5 provides an indication of outlet versus inlet pressure for the regulator of FIG. 3.

[0027] FIG. 6 provides a graph showing the gas pressure within a hood utilizing regulators of the present disclosure versus unregulated flow from the same pressure of cylinders.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] An embodiment of a breathing apparatus (1000) is shown in FIG. 1, and generally comprises a hood (1001) and a housing (2001). The hood (1001) surrounds the user's head and contains a breathable atmosphere. The housing (2001) holds elements that function to provide gas purification and/or oxygen enrichment for the atmosphere within the hood (1001), thereby providing support for the respiration of the user wearing the hood (1001). Such a breathing apparatus (1000) is designed to provide protection from dangerous external environments, such as are presented by, though not limited to, smoke or fire, or chemical, biological, radiological or nuclear hazards, that might otherwise negatively impact any or all of the biological and physiological functions central to a user's head, such as sight and respiration and so many other bodily functions that can be detrimentally impacted by inhaled hazards.

[0029] An aspect of the apparatus (1000) is a hood (1001) that is large enough to surround a person's head. The hood (1001) is constructed at least in part of a transparent or translucent material through which the user can see when wearing the hood (1001). The hood (1001) includes a neck seal subassembly (1003), which provides an opening (1004) through which a user's head is moved when donning the hood (1001). In an embodiment, the neck seal subassembly (1003) functions like an elastomeric membrane allowing the opening (1004) to expand to allow a user's head into the hood (1001) and then to contract to seal snuggly around the user's neck, essentially separating the environment inside the hood (1001)—an internal volume in which resides the user's head—from the environment outside the hood (1001).

[0030] In the embodiment shown in FIG. 1 the hood (1001) is supplied oxygen from two compressed gas cylinders (3004a) and (3004b) which jointly comprise an oxygen source. While in other embodiments, other oxygen sources, such as solid state chemical oxygen generators, are used, the depicted embodiment utilizes two compressed gas cylinders (3004a) and (3004b) which is typical for a PBE. The first cylinder (3004a) will be intended to primarily supply till gas for the hood to bring the hood to an initially selected positive pressure. The second cylinder (3004b) will provide a lower rate of oxygen gas and is primarily intended to supply oxygen at a rate roughly consistent with the expected use rate of a human user using the hood.

[0031] In the depicted embodiment, each of the cylinders (3004a) and (3004b) is attached to an associated micro regulator (3003a) and (3003b) for controlling release of oxygen from the cylinder (3004a) and (3004b) through regulation of the flow rate thereof. To start the flow of oxygen from the cylinders (3004a) and (3004b) prior to donning the hood (1001), a user operates an actuator, which in an embodiment is a spring biased pin that punctures a disk of the cylinders (3004a) and (3004b) to release the compressed gas contained therein into the regulator (3003a) or (3003b).

[0032] In an embodiment, the cylinders (3004a) and (3004b) initially are pressurized to about 3000 psig, and each contains about 18 liters of oxygen gas. The oxygen gas will typically be aviator's grade as compared to other grades of oxygen but that is not required for functionality (but may be required by regulation).

[0033] The hood (1001) may include one or more purification devices, which may include but are not limited to, particulate filtration or chemical purification, such as catalytic oxidation or adsorption. This may comprise a solid chemical substrate that chemically adsorbs or otherwise separates carbon dioxide from the gas drawn from the internal hood (1001) volume. Carbon dioxide may be removed from within the hood (1001) because of the constant enrichment with carbon dioxide of the gas within the internal hood (1001) volume due to the user's respiration. In an embodiment this comprises a form of lithium hydroxide adsorbent such as sheets or granules.

[0034] The two different cylinders (3004a) and (3004b) will typically each be provided with regulators having different flow rates so that they can each meet the requirements of the specific purpose of the cylinder. However, in an alternative embodiment, only the second cylinder (3004b) or first cylinder (3004a) will be supplied with a regulator. Commonly if only one regulator is provided it will be a regulator (3003b) for the second cylinder (3004b).

[0035] The first cylinder (3004a) will typically be designed to provide for rapid inflation of the hood (1001) to operating pressure. As such, the first regulator (3003a) will typically have a relatively high flow rate compared to the second regulator (3003b). In particular, the first regulator (3003a) will typically be designed to fully inflate the hood (1001) in less than 30 seconds. The cylinders (3004a) and (3004b) will typically deliver around 6-9 liters of oxygen to the hood (1001) in the first 20 seconds, therefore the flow rate of the first regulator (3003a) will typically be around 15-27 liters/per minute and often around 20 liters/per minute.

[0036] As indicated above, both cylinders (3004a) and (3004b) will typically have around 18 liters of oxygen which means that not all the oxygen in a single tank is necessary for inflation. However, as the regulator (3003a) will typically not be able to cut back on the rate after the hood (1001) is inflated, increased rate at the beginning will generally be accepted to deal with time for the user to don the breathing apparatus (1000) as inflation will typically begin before the breathing apparatus (1000) is placed over the head to making donning simpler and to avoid concerns of placing the head in the hood prior to inflation (and lack of oxygen therein).

[0037] The second regulator (3003b) will typically supply make up oxygen for the hood (1001) as oxygen is consumed by the user's breathing. In an embodiment, the second regulator (3003b) allows an oxygen flow rate in the range of about two liters per minute to about six liters per minute.

[0038] It should be recognized that the value of the regulator is that the regulators (3003a) and (3003b) allow for the more effective use of oxygen. Specifically, the regulators (3003a) and (3003b) provide increased useful life to the extent that they result in a sufficient reduction of oxygen waste, that the weight of the oxygen loss reduction is greater than the weight of the regulators. That is, the amount of oxygen in the tanks may be reduced by the weight of the regulators, but the regulated flow provides for oxygen supply from that reduced amount for the same or greater time than is provided by the increased weight of oxygen without the regulators being used.

[0039] FIGS. 2 and 3 provide for a number of embodiments of microregulators which can supply for effective regulation with very little weight. FIG. 2 shows a microregulator (100) utilizing a micro compression spring (701) for regulation while FIG. 3 shows a microregulator (200) utilizing a series of wave washers (901) for regulation. Either of microregulator (100) or microregulator (200) may be used as regulator (3003a) and/or regulator (3003b) While the biasing members being different does provide for some different structure, FIGS. 2 and 3 share a number of common parts. In the FIGS, common numbers represent common parts. Specifically, both regulators (100) and (200) each comprise a housing (101) which is generally comprised of two separable components (103) and (105). The back housing (105) is typically designed to interface with the hood (not shown) so that oxygen is supplied from the tank (not shown) and through the exit orifice (517) to enter the hood. This oxygen comes through entrance orifice (303), into channel (301) and the hollow interior (305) of the front housing (103), and exits into the channel (511) and ultimately the exit orifice (517).

[0040] The back housing (105) is attached to the opposing side of the front housing (103) to entrance orifice (303). As such, it effectively closes the hollow interior (305). The back housing (105) includes a hollow stem (501) which is designed to interface with a tube, directly with the hood (not shown), or with another structure where the oxygen flow will be provided to the hood. The channel (511) of the stem (501), therefore, is open on one end (505) to the hollow interior (305) of the back housing (103).

[0041] The opposing end (507) comprises exit orifice (517). The channel (511) in the embodiment of FIGS. 2 and 3 is stepped so that the exit orifice (517) forms the end of the narrowest portion of the channel (511) and comprises the first step. The channel (511) then expands to section (519), expands again to section (513), and expands again to section (515) which includes the open end (505).

[0042] Within the hollow interior (305) of the front housing (103), there is included the valve piston (107) and (109). The specific shape of the valve piston (107) and (109) depends on the embodiment as their shape will generally be altered to correspond to the biasing mechanism (701) or (901) being used. However, the valve pistons (107) and (109) are similar in that they both provide the same function of moving back and forth against a biasing system to regulate the flow of gas from the channel (301) and entrance orifice (303) into the hollow interior (305) and the channel (511). Further, both valve pistons (107) and (109) are of a general “T” shape with a larger piston face (601) facing the back housing (105) and an extended shaft (603) opposing. The larger piston face (601) acting to provide a larger surface for the flowing gas to push against the end of the extended shaft (603) resulting in the regulation action.

[0043] Flow from the entrance orifice (303) will typically be controlled by the movement of the piston (107) and (109) and specifically the extended shaft (603). The extended shaft (603) can move generally linearly (left and right across the page in FIGS. 2 and 3) and will variably contact a seat (307) with the opposing seat (607). When the two seats (307) and (607) are in contact, oxygen flow from the entrance orifice (303) is generally inhibited as the pressure of the oxygen in the channel (511) pushing rightward in FIG. 2 or 3 against the piston face (601) is greater than the pressure in the channel (301) in combination with the force of the biasing mechanism (701) or (901) which will cause the flow to cease.

[0044] As the pressure in the channel (511) decreases from flow exiting the channel (511) via the exit orifice (507), this rightward pressure on the piston face (601) decreases causing the piston (107) or (109) to move leftward allowing additional gas to flow from channel (301). As this flows into channel (511) the corresponding increase in pressure in chamber (515) causes the piston (107) or (109) to again move rightward reducing the flow.

[0045] It should be apparent from the above that the movement of the piston (107) or (109) in conjunction with the pressure of the gas on piston face (601) will essentially result in an equilibrium state where the pressure in chamber (515) and the biasing force of the biasing member (701) or (901) are equaled at a specific flow of gas from the entrance orifice (303). This, in conjunction with elements of the stepped nature of channel (511) sets the pressure of the gas flowing from exit orifice (507)

[0046] The seats (607) in the regulators (100) and (200) will typically be different from seats in the same position on larger regulators. In larger regulators, the seat (607) will typically comprise a plastic or rubber insert so that the seat (607) will form a seal with the flat top and slanted sides of the conical frustum which forms the seat (307). However, in a particularly small regulator (100) and (200) making such an insert (and inserting it) is very difficult. Thus, while it is not required, the seat (607) is typically machined from the same metal as the piston (107) or (109) with no insert. The seat (307) will typically be a conical frustum so the flat face of the seat (307) will form a metal to metal seal against the seat (607). As the regulator (109) and (107) is so small, so long as it is well machined, this surface to surface contact will generally prohibit gas flow when the pressure on surface (601) is sufficiently high.

[0047] As indicated above, regulation is provided via a biasing member (701) or (901) which serves to bias the valve piston (107) or (109) toward an open position. Thus, when gas pressure is present in chamber (515) the pressure will push against the face (601). If the pressure is sufficient, the piston (107) or (109) will move to position the two seats (307) and (309) against each other. However, when the piston (107) or (109) is in this position gas cannot flow to the chamber (515) from the channel (303).

[0048] The biasing member (701) or (901) is typically positioned so as to push against the lower surface (611) of the top of the “T” shape of the piston (601). In FIG. 2, this is against an interior opening to help constrain the narrower spring (701) while in FIG. 3 it is on the wider portion of the “T” as the disk spring (901) is typically wider.

[0049] If the biasing force is sufficient, the piston (107) or (109) will move and open the gas channel (301) by unseating the seats (307) and (607). Once gas enters the hollow interior (305) it will flow to the chamber (515). As the gas in chamber (515) is somewhat slow to leave due to the gradually restricting shape of channel (511), the gas will serve to push the face (601) of piston (107) or (109) back toward the channel (301) and the reseating of (307) and (607). This movement is resisted by the biasing member (701) or (901).

[0050] The equilibrium position will generally result in some gas from entrance orifice (303) arriving in a steady stream as the same pressure (amount) is lost from the chamber (515) through the channel segments (513) and (519) and out the exit orifice (517). The results is that the pressure of the gas in chamber (515), is reduced compared to the pressure that oxygen is supplied via the entrance orifice (301) due to the gas in chamber (515) having a greater surface area to push against compared to gas in the narrow channel (301). The specific pressure of the released gas is typically based on the pressure in the oxygen tank and the biasing force supplied by the biasing member along with the specific size of the various chambers (515), (513), (519) and (301) and orifices (517) and (301).

[0051] In FIG. 2, the biasing member comprises a compression coil micro spring (701). Use of coil springs in regulators has been carried out in larger regulators. However, in larger regulators the spring is generally constrained in a housing between an inner wall (703) surrounding the path through which the extended leg of the piston will travel, and an outer wall contacting the outer surface of the spring coil. The outer wall typically is used to keep the spring from bulging outward when compressed because coil springs are typically quite thin in cross section of the coil. In the embodiment of FIG. 2, there is the inner wall (703) but no outer wall as the position of an outer wall has been replaced by slanted surface (705) arranged at a distance from the coil of spring (701). This is done because machining of an inner and outer wall structure at this size is not commercially feasible using current machining techniques as the coil cross section is too small for desired machining methods. Using a slant wall (705) is relatively easy to machine and has proven functional to support the spring (701).

[0052] In the regulator (200) of FIG. 3, the coiled spring is not present and a disk spring or stack of wave washers (901) is used instead. This is typically preferred as the small size of the regulator (200) is well suited to the small available stroke typically offered by stacked wave washers (901). The location (907) of the wave washers (901) does not need to be as deep as for coil spring (701) and is typically wider. However, as the wave washers may be able to move relative to each other, inclusion of an inner wall (908) and outer wall (909) both in contact with the inner and outer surfaces, respectively, of the washer stack (901) is desirable to retain the washers. However, as the stacked washers are much larger in cross section, machining of these walls is much more feasible than it typically is for the coil spring (701).

[0053] Use of the regulator (100) or (200) will typically connect between the oxygen tanks and the hood. As can be seen in FIGS. 4 and 5, the regulators (100) and (200) can be used with relatively high input pressure to produce desired output pressures in the range of use for such a regulator in a PBE. Typically two different regulators will be used with the oxygen tanks, one will be used with the first oxygen tank to quickly fill and pressurize the hood, the second will be used to provide for a steady stream of gas over time. It is important for a regulator in a PBE, to supply gas in a more efficient manner (based on effective life that the gas in the hood remains breathable) to make up from the loss of gas source to counteract the weight of adding the regulator.

[0054] FIG. 6 provides for a chart showing comparison of a regulated hood filling and supply pattern (1101) compared to an unregulated filling and supply pattern (1103). As can be seen, in the regulated pattern, initial inflation can actually occur quicker, the first tank is exhausted, and the flow rapidly falls off to a relatively constant amount which is maintained for essentially a full ten minutes (600 seconds) giving the hood a good operational life of around 10 minutes. In the unregulated case, the inflation is a little slower, and the fall off rate is more curved. In the area (1105) the unregulated system is effectively providing too much gas and the rate rapidly falls below the regulated amount at around 240 seconds (4 minutes). While gas flow is likely still sufficient after that to maintain inflation, the operational life is likely less than the 10 minutes of the regulated system (1101). Thus, the regulators would appear to provide for increased operational life countering their weight of inclusion.

[0055] The regulated PBE will generally be stored prior to use in a vacuum sealed barrier pouch that is intended to be opened only at the time the PBE will be used, such as when needed to be donned quickly in an emergency. Such sealed storage maintains the cleanliness of the apparatus PBE.

[0056] To use the PBE shown in FIG. 1, a user will generally remove the PBE from the vacuum-sealed barrier pouch by tearing open the vacuum-sealed pouch and removing the PBE. The user operates an actuator which begins the flow of oxygen through the first regulator and into the hood to inflate the hood. The user will generally place both hands inside a neck seal opening and slide the opening over the user's head so the user's head is positioned inside the hood. The user then removes the user's hands from the opening allowing the neck seal to seal securely around the user's neck.

[0057] After it has been donned, the first tank will typically be rapidly depleted of oxygen and the flow will primarily be from the second tank. This is the flat portion of FIG. 6. Because the flow is regulated, this flow is much flatter and therefore more consistent than the flow from an unregulated tank. The user can breathe normally inside the hood. When the second oxygen source is depleted, the hood will start to rapidly deflate (beginning at point (1107) on FIG. 6) as there is basically no more oxygen available. This deflation indicates that the hood needs to be removed.

[0058] While the invention has been disclosed in conjunction with a description of certain embodiments, including those that are currently believed to be useful embodiments, the detailed description is intended to be illustrative and should not be understood to limit the scope of the present disclosure. As would be understood by one of ordinary skill in the art, embodiments other than those described in detail herein are encompassed by the present invention. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention.

[0059] It will further be understood that any of the ranges, values, properties, or characteristics given for any single component of the present disclosure can be used interchangeably with any ranges, values, properties, or characteristics given for any of the other components of the disclosure, where compatible, to form an embodiment having defined values for each of the components, as given herein throughout. Further, ranges provided for a genus or a category can also be applied to species within the genus or members of the category unless otherwise noted.

[0060] The qualifier “generally,” and similar qualifiers as used in the present case, would be understood by one of ordinary skill in the art to accommodate recognizable attempts to conform a device to the qualified term, which may nevertheless fall short of doing so. This is because terms such as “orthogonal” are purely geometric constructs and no real-world component or relationship is truly “orthogonal” in the geometric sense. Variations from geometric and mathematical descriptions are unavoidable due to, among other things, manufacturing tolerances resulting in shape variations, defects and imperfections, non-uniform thermal expansion, and natural wear. Moreover, there exists for every object a level of magnification at which geometric and mathematical descriptors fail due to the nature of matter. One of ordinary skill would thus understand the term “generally” and relationships contemplated herein regardless of the inclusion of such qualifiers to include a range of variations from the literal geometric meaning of the term in view of these and other considerations.