A compact powered air-purifying respirator with improved airflow efficiency

Abstract

A compact, mask-mountable powered air-purifying respirator ("PAPR") includes a housing and an impeller driven by a motor that draws air in through an inlet in the housing and directs the air to an outlet at the opposite end of the housing. The impeller consists of S-shaped fan blades that direct air radially outward from the bottom of the impeller. The radial airflow impinges on the S-shaped fins of the flow straightener, redirecting the airflow downward through the outlet of the PAPR housing. The fan blades and flow straightener improve airflow efficiency by driving the airflow directly and efficiently without unnecessary movement of air through the PAPR assembly.

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 324,045, entitled "POWERED AIR PURIFYING RESPIRATOR," filed by the applicant on March 26, 2022, the specification of which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to powered air-purifying respirators, and more particularly to a compact or "micro" sized powered air-purifying respirator configured for removably attachment to a filter canister and a respirator, providing improved airflow efficiency over previously known PAPR configurations. [Background technology]

[0003] Powered air-purifying respirators ("PAPRs") are frequently used by emergency responders, industrial workers, healthcare workers, and others operating in potentially hazardous environments to provide respiratory protection against airborne contaminants. A typical PAPR configuration includes a blower unit that draws air through a filter cartridge attached to the blower inlet, and an outlet that is ultimately in fluid communication with the breathing zone of the user's equipment, such as the breathing zone inside the protective mask, via a hose that is attached to both the blower outlet and the user's protective mask. The challenge in selecting and configuring a PAPR lies in finding one that provides sufficient airflow to ensure adequate respiratory protection while maintaining user comfort and overall mobility.

[0004] The ability of a PAPR to provide such protection depends on the PAPR's airflow efficiency as well as its ability to successfully filter and purify the air before it is delivered to the operator. Unfortunately, previously known PAPR configurations often suffer from inefficient airflow, resulting in poor filter performance, reduced user respiratory function, increased energy consumption, and, at times, increased user discomfort resulting from excessive heat and humidity. For example, previously known PAPR configurations often employ complex or tortuous air flow paths through blower units, resulting in increased pressure loss and power consumption. Additionally, previously known PAPR configurations tend to be bulky and not easily attached directly to the user's respirator, which may impede the user's freedom of movement. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there remains a need in the art for a PAPR that can provide improved airflow efficiency over previously known configurations, and that can provide such improved performance in a compact configuration that can be attached directly to a user's mask to ensure user mobility and comfort. [Means for solving the problem]

[0006] According to an embodiment of one aspect of the present invention, a compact, mask-mountable PAPR is provided that provides improved airflow efficiency over previously known PAPR configurations. The PAPR draws air in through an inlet in an upper housing and delivers air to an outlet in a lower housing, which delivers filtered air to a wearer's breathing zone, such as inside the user's protective mask. A motor-driven impeller rotates to draw air in through an inlet in the housing, and generally S-shaped fan blades on the impeller direct the air radially outward from the bottom of the impeller. The radial airflow immediately strikes the S-shaped fins of a flow straightener, redirecting the airflow downward from the outlet of the housing. The impeller fan blades and flow straightener fins are specifically configured to drive the airflow more immediately and directly downward, without additional air movement through the interior of the PAPR assembly, thereby reducing pressure losses associated with additional air movement through the interior of the PAPR assembly and providing improved airflow efficiency over previously known devices.

[0007] According to certain aspects of embodiments of the invention, the PAPR is compact and mountable directly to a user's protective mask. The improved airflow efficiency of PAPRs constructed in accordance with at least certain aspects of the invention allows for increased performance and respiratory protection while reducing energy consumption, and the compact, mountable design allows for greater freedom of movement for the user.

[0008] Further aspects, features and advantages of the present invention will become readily apparent from the following detailed description, which merely illustrates a number of specific embodiments and implementations, including the best mode contemplated for carrying out the invention. The invention is also capable of other and different embodiments, and its several details can be modified in various obvious respects without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

[0009] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized. The invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a top perspective view of a compact, mask-mountable PAPR according to one aspect of an embodiment of the present invention. [Diagram 2] FIG. 2 is a bottom perspective view of the compact, mask-mountable PAPR of FIG. [Diagram 3] FIG. 3 is a side view of the compact, mask-mountable PAPR of FIG. [Figure 4] 4 is a side cross-sectional view of the compact, mask-mountable PAPR of FIG. 1 taken along section line AA of FIG. [Diagram 5] FIG. 5 is an exploded view of the compact, mask-mountable PAPR of FIG. [Figure 6] FIG. 6 is a side view of the upper housing of the compact, mask-mountable PAPR of FIG. [Figure 7] FIG. 7 is a side cross-sectional view of the upper housing taken along section line BB of FIG. [Figure 8] FIG. 8 is a bottom view of the upper housing of FIG. [Figure 9] FIG. 9 is a side view of the lower housing of the compact, mask-mountable PAPR of FIG. [Figure 10] 10 is a side cross-sectional view of the lower housing taken along section line CC in FIG. [Figure 11] 11 is a top view of the lower housing of FIG. [Figure 12] 12 is a bottom view of the lower housing of FIG. [Figure 13] FIG. 13 is a side view of the impeller of the compact, mask-mountable PAPR of FIG. [Figure 14] FIG. 14 is a side cross-sectional view of the impeller taken along section line DD in FIG. [Figure 15] FIG. 15 is a top view of the impeller of FIG. [Figure 16] FIG. 16 is a bottom view of the impeller of FIG. [Figure 17] FIG. 17 is a top perspective view of the impeller of FIG. [Figure 18] FIG. 18 is a side view of a flow straightener for the compact, mask-mountable PAPR of FIG. [Figure 19] 19 is a side cross-sectional view of the flow straightener taken along section line EE of FIG. [Figure 20] FIG. 20 is a top view of the flow straightener of FIG. [Figure 21] FIG. 21 is a bottom view of the flow straightener of FIG. [Figure 22] 22 is a top perspective view of the flow straightener of FIG. [Figure 23] 23 is a top perspective view of a flow straightener installed in the lower housing of the compact, mask-mountable PAPR of FIG. 1. [Figure 24] FIG. 24 is a top view of a flow straightener installed in the lower housing of the compact, mask-mountable PAPR of FIG. [Diagram 25] FIG. 25 is a detailed side view showing the relative positions of the impeller and the flow straightener. [Figure 26] FIG. 26 is a schematic diagram of airflow through the compact, mask-mountable PAPR of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention can be understood by referring to the following description and the accompanying drawings. To enable embodiments of the present invention to be practiced, the following description of the embodiments is not intended to limit the preferred embodiments, but to serve as specific examples thereof. Those skilled in the art should appreciate that they can readily use the disclosed concepts and specific embodiments as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also appreciate that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form.

[0012] Descriptions of well-known functions and structures are omitted for clarity and brevity. The terms used herein are for the purpose of describing particular embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, the use of the terms a, an, etc. does not denote a limitation of quantity but rather denotes the presence of at least one of the referenced item.

[0013] The use of terms such as "first", "second", etc. does not imply a particular order, but rather is included to identify particular elements. Moreover, the use of terms such as first, second, etc. does not indicate an order of importance, but rather terms such as first, second, etc. are used to distinguish one element from another. It will be further understood that, as used herein, the terms "comprises" and / or "comprising", or "includes" and / or "including" specify the presence of stated features, regions, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0014] Although some features are described with respect to individual exemplary embodiments, aspects need not be limited thereto, and features from one or more exemplary embodiments may be combined with other features from one or more exemplary embodiments.

[0015] Unless otherwise stated, the dimensions shown in the accompanying drawings are exemplary and should not be construed as limiting the scope of the present invention to those specific dimensions.

[0016] In accordance with certain aspects of the exemplary embodiment, and with particular reference to Figures 1 and 2, a powered air-purifying respirator ("PAPR") 100 comprises an upper housing 104 and a lower housing 102 secured together to form a unitary, sealed PAPR body. The upper housing 104 includes an internally threaded inlet opening 105 configured to receive a filter canister, for example, an externally threaded 40 mm filter canister having a configuration well known to those skilled in the art. A centrifugal impeller 106 is rotatably mounted within the PAPR body and extends through the base of the inlet opening 105, such that when a filter canister is mounted to the inlet opening 105 and the impeller 106 is rotating, air is drawn through the filter canister and into the body of the PAPR 100. The air so filtered is directed through the body of the PAPR 100 to and discharged from an externally threaded outlet opening 103 configured for threaded attachment of a respirator, such as an M53 or FM54 respirator, as described in more detail below. The PAPR 100 configured in this manner draws air into the PAPR 100 via the inlet opening 105, and as the impeller 106 rotates, the air is first drawn through a filter canister (not shown) attached to the inlet opening 105, and then directed to the outlet opening 103 and downstream into the interior of a user's respirator (not shown) to allow the user to breathe filtered air.

[0017] Preferably, the bottom surface 102(a) of the lower housing forms a concave surface which allows the PAPR 100 to fit tightly against the outside of the user's protective mask when the exit opening 103 is attached to the inlet of the user's protective mask, thus minimizing visibility obstructions that may be caused by a larger assembly.

[0018] 3-5, the PAPR 100 is powered by a battery 112 disposed within the PAPR 100. In an exemplary configuration, the battery 112 is comprised of a lithium battery, such as, by way of non-limiting example, a CR123 battery, with the PAPR 100 comprising a self-contained power source. A removable battery cover 104a is provided on the upper housing 104 to allow for replacement and / or repair of the battery 112. Similarly, in certain exemplary configurations, a remote battery pack connection port may provide an alternative to an on-board battery power source in the event that the on-board battery 112 is depleted. Similarly, the electronics 114 that control the PAPR are likewise housed within the PAPR 100 and may include power control, selection of operating modes, and other electronic control functions as would occur to one of ordinary skill in the art. A manually operable on / off switch 107 is provided on the exterior of the housing where it is easily accessible to the user and is in electrical communication with the electronics 114 to selectively operate the PAPR 100.

[0019] With particular reference to the cross-sectional view of FIG. 4, the PAPR 100 includes a motor 108 mounted within a motor mount 109 within the lower housing 102. The motor 108 has a motor shaft secured to the impeller 106 for rotating the impeller 106 with power from the motor 108. In an exemplary configuration, the motor 108 is configured as a 4.5V motor, which is sufficient to operate the impeller 106 without significantly increasing the weight of the overall assembly. The shaft of the motor 108 mounts the impeller 106 such that the impeller 106 is adjacent the bottom of the female threaded inlet opening 105. The bottom of such female threaded inlet opening 105 forms an impeller receiver 120 (FIG. 7) having a contour matching the contour of the top surface of the impeller 106, as described in more detail below. Additionally, a flow straightener 110 is secured within the lower housing 102, as described in more detail below. The flow straightener 110 includes fins 140 including outer edges adjacent to and parallel to the outer edges of the fan blades 130 of the impeller 106, such that as the impeller 106 rotates and draws air into an upper portion of the impeller 106 and expels it radially from a lower portion of the impeller 106, such radially expelled airflow immediately impacts the fins 140 of the flow straightener 110, redirecting the airflow downwardly and expelling it through the outlet opening 103 of the lower housing 102.

[0020] 6, 7, and 8 show a side view, a cross-sectional view, and a bottom view, respectively, of the upper housing 104. The upper housing 104 has a generally cylindrical side wall 116 and a convex top wall 117, with the inlet opening 105 extending downwardly from the center into the convex top wall 117. The central portion of the top wall 117 recessed into the inlet opening 105 defines an impeller receiver 120, the contour of which also matches the contour of the upper surface of the centrifugal impeller 106. The impeller receiver 120 defines an outer circumferential notch 118 and an inner circumferential notch 119. The outer circumferential notch 118 matches the contour of the outer, upwardly extending rim 136 of the impeller 106, and the inner circumferential notch 119 matches the contour of the inner, upwardly extending rim 134 of the impeller 106, providing a close but non-contacting fit (i.e., sufficient to allow rotation of the impeller 106) between the upper surface of the impeller 106 and the lower surface of the impeller receiver 120.

[0021] Similarly, Figures 9, 10, 11 and 12 show side, cross-sectional, top and bottom views, respectively, of the lower housing 102. As best shown in Figures 9 and 10, the bottom surface 102(a) of the lower housing 102 defines a convex bottom surface from the outer edge of the lower housing 102 to the centrally located male threaded outlet opening 103. A plurality of radial ribs 122 extend between the motor mount 109 and the inner wall of the outlet opening 103. The upper end of the outlet opening 103 forms a flow straightener receiver 142, which fixedly mounts the flow straightener 110 to the lower housing 102. In certain configurations, the flow straightener 110 may optionally be formed integrally with the lower housing 102. A battery receiver 123 may similarly form a cradle on the upper surface of the lower housing 102 for removably receiving and holding the battery 112.

[0022] 13, 14, 15, 16, and 17, which respectively show a side view, a cross-sectional view, a top view, a bottom view, and a perspective view of the impeller 106. The impeller 106 includes fan blades 130 that direct airflow downward through the impeller 106 and out a radial impeller outlet 132. The upper surface of the impeller 106 includes an upwardly extending inner rim 134, an upwardly extending outer rim 136, and a fan blade circumferential rim 137. As mentioned above, the rims 134 and 136, along with the remaining contour of the top of the impeller 106, match the contour of the impeller receiver 120 on the upper housing 104. This mating configuration of the impeller 106 and impeller receiver 120 makes it more difficult for air passing through the PAPR 100 to recirculate from the outlet opening to the inlet of the impeller 106. The fan blades 130 extend outwardly from a central hub 124 (through which extends a motor mount shaft that is secured to the shaft of the motor 108) to an inner surface of a fan blade peripheral rim 137. Each fan blade 130 has a fan blade upper edge 126 that extends linearly outwardly from the central hub 124 to an edge of the fan blade 130 adjacent the fan blade peripheral rim 137. Similarly, each fan blade 130 has an outer edge that extends downwardly from the upper edge 126 to define an airflow path between adjacent fan blades. An upper outer edge 127 of each fan blade 130 extends downwardly from the fan blade upper edge 126 along a curve, and a lower outer edge 127 of each fan blade 130 extends downwardly from the upper edge 127 along a curve that follows the contour of the underside of the impeller body, the curve of the lower edge 127 being less steep than that of the upper edge 126. With this configuration, each fan blade 130 provides a generally S-shaped configuration in which air drawn into the upper portion of the impeller 106 is directed generally radially outward through radial impeller outlets 132 at the lower portion of the impeller 106. The bottom of each fan blade 130 defines a generally straight fan blade outer edge 129 that is angled to match the angle of the inner straight fin edges 144 on the fins 140 of the flow straightener 110, as will be described in more detail below. As best seen in Figures 14 and 16, the bottom of the impeller 106 defines a solid partial bell-shaped closed bottom wall 131.

[0023] 18, 19, 20, 21, and 22, which respectively show side, cross-sectional, top, bottom, and perspective views of the flow straightener 110. The flow straightener 110 includes a plurality of fins 140, each having a straight inner fin edge 144 and a generally S-shaped curved outer edge 145, which further aid in directing the flow through the PAPR 100. Each of the inner straight fin edges 144 extends outwardly from a central flow straightener hub 143 at an angle that matches the angle of the fan blade outer edge 129 of the impeller 106. As best shown in FIGS. 23 and 24, the flow straightener 110 is fixedly disposed within a flow straightener receiver 142 of the lower housing 102, with the motor 109 extending upwardly through the open interior of the flow straightener 110. As best seen in FIG. 25 (showing the combination of motor 108, flow straightener 110, and centrifugal impeller 106), as motor 108 rotates impeller 106 (while holding flow straightener 110 stationary), centrifugal impeller 106 draws air in through the female-threaded inlet opening 105 at the top of the PAPR 100 (and through an attached cartridge filter) and accelerates the airflow through the top of the impeller 106 toward the radial outlet 132 of the impeller 106. The radially exiting airflow from impeller 106 immediately contacts fins 140 of flow straightener 110, redirecting the airflow downward and forcing the airflow out the bottom of the PAPR 100 through the male-threaded outlet opening 103 (and into the user's respirator). FIG. 26 illustrates a velocity diagram as air is drawn through the PAPR 100 configured as described above during operation, with the radially exiting airflow from the impeller 106 preferably being directed immediately downwardly by the flow straightener 110 to avoid spiraling around the interior of the PAPR 100 as in conventional PAPR designs.

[0024] In an exemplary configuration, a PAPR 100 configured in accordance with at least certain aspects of the present invention described above can operate the PAPR 100 at temperatures between -30°C and 49°C and can have an operating mode of 45-50 liters per minute ("LPM") and a breath rate responsive ("BRR") operating mode controlled by electronics 114 within the PAPR 100, and an operating mode of 25-65 LPM.

[0025] In summary, PAPRs constructed in accordance with at least certain aspects of the present invention provide improved airflow efficiency and reduced bulk compared to previously known PAPR configurations, making them a more practical and comfortable solution for respiratory protection in a variety of operational environments. The unique impeller and flow straightener designs described herein provide a more direct and efficient air movement path, reducing the risk of harmful particulates and gases reaching the user's respiratory system.

[0026] While the preferred embodiments and specific modifications of the concepts underlying the present invention have been fully described above, various other embodiments, as well as specific variations and modifications of the embodiments shown and described herein, will naturally occur to those skilled in the art upon understanding said concepts. It is therefore to be understood that the present invention may be practiced otherwise than as specifically described herein.

Claims

1. a PAPR body having an upper housing having an inlet adapted to be attached to a filter cartridge and a lower housing having an outlet adapted to be attached to a protective mask; an impeller rotatably mounted within the PAPR body, the impeller having an impeller body defining an impeller air inlet aligned with the upper housing inlet and an impeller air outlet configured to radially exit air from the impeller; a flow straightener in the PAPR body disposed adjacent the impeller air outlet and having a plurality of fins corresponding to a shape of the impeller air outlet; The fins are configured to redirect radial airflow from the impeller into an axial airflow through the lower housing outlet.

2. 2. The powered air purifying respirator of claim 1, wherein the lower housing has a concave bottom exterior wall surrounding the outlet.

3. 10. The powered air purifying respirator of claim 1, wherein the impeller further comprises a plurality of S-shaped fan blades.

4. 4. The powered air purifying respirator of claim 3, wherein the fan blades further comprise upper edges extending linearly outwardly from a central hub of the impeller.

5. 4. The powered air purifying respirator of claim 3, wherein the fan blade further comprises an upper outer edge extending downwardly from an upper end of the blade along a first curve.

6. 6. The powered air purifying respirator of claim 5, wherein each of the outer edges of each of the fan blades further comprises a lower outer edge portion extending downwardly from the upper outer edge portion along a second curve that continues to a lower surface of the impeller body.

7. 7. The powered air purifying respirator of claim 6, wherein the second curve is less steep than the first curve.

8. 4. The powered air purifying respirator of claim 3, wherein the impeller further comprises a partial bell-shaped closed base having a central hub.

9. 10. The powered air purifying respirator of claim 8, wherein the PAPR further comprises a motor within the PAPR body, the motor drivingly mounted to a motor bearing in the central hub of the impeller.

10. 4. The powered air purifying respirator of claim 3, wherein the fins of the flow straightener further comprise S-shaped fins.

11. 11. The powered air purifying respirator of claim 10, wherein an outer edge of each of the fins extends at an angle parallel to an angle of an outer edge of each of the fan blades of the impeller.

12. a PAPR body having an upper housing having an inlet configured to attach to a filter cartridge and a lower housing having an outlet configured to direct purified air to a protective mask; a centrifugal impeller rotatably mounted within the PAPR body, the impeller having an impeller body defining an impeller air inlet aligned with the upper housing inlet and a plurality of S-shaped fan blades configured to radially eject air from the impeller; a fixed flow straightener within the PAPR body disposed adjacent each end of the S-shaped fan blades and having a plurality of fins corresponding to the shape of the ends; The fins are configured to redirect radial airflow from the impeller into an axial airflow through the lower housing outlet.

13. 13. The powered air purifying respirator of claim 12, wherein the lower housing has a bottom, concave exterior wall surrounding the outlet.

14. 13. The powered air purifying respirator of claim 12, wherein the impeller further comprises a partial bell-shaped closed bottom wall having a central hub.

15. 15. The powered air purifying respirator of claim 14, wherein the fan blades extend between a closed bottom wall of the partial bell shape and a top of the impeller.

16. 13. The powered air purifying respirator of claim 12, further comprising a motor drivingly attached to said impeller.

17. 13. The powered air purifying respirator of claim 12, wherein the fins of the flow straightener further comprise S-shaped fins.

18. 18. The powered air purifying respirator of claim 17, wherein an outer edge of each of the fins extends at an angle that is parallel to an angle of an outer edge of each of the fan blades of the impeller.

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