Abstract:
A supplied air respirator ( 10, 50 ) that includes a clean air source ( 16, 54 ), a facepiece ( 18, 18′ ), a hose ( 12, 52 ), and a hose adjustment mechanism ( 14, 34 ). The clean air source ( 16, 54 ) is designed to be carried by a user of the ( 10, 50 ), and the face piece ( 18, 18′ ) is sized to fit at least over the user&#39;s nose and mouth. The hose ( 12 ) extends from the clean air source ( 16, 54 ) to the facepiece ( 18, 18′ ). The hose adjustment mechanism ( 14, 36 ) enables the hose length to be controlled so that slack is eliminated between the clean air source ( 16, 54 ) and the facepiece ( 18, 18′ ). The supplied air respirator ( 10, 50 ) is beneficial and that it reduces opportunities for the hose ( 12, 52 ) to become inadvertently caught on an article located in the work environment.

Description:
[0001]    The present invention pertains to a supplied air respirator that uses an adjustable length hose as a conduit between the respirator facepiece and the clean air supply source. 
       BACKGROUND 
       [0002]    Supplied air respirators are regularly worn in environments where the surrounding air contains contaminants. Clean air is delivered to the wearer from a supply tank or from a powered air source that drives the ambient air through an air filter. 
         [0003]    Systems that use a powered air source to supply clean air to the wearer are referred to as powered air purifying respirators—known shorthand as “PAPRs”. PAPRs typically have two main parts: a facepiece and a filtering unit. The facepiece is worn at least over the nose and mouth of the user (it also may cover the eyes and ears), and the filtering unit is commonly worn about the user&#39;s waist. The filtering unit often includes filter cartridges, a housing, a fan, and an electric motor that drives the fan. The fan and motor are contained within the housing, and the filter cartridges are attached to the housing body. Ambient air is filtered by being forced through filter elements that are contained within the filter cartridges. This filtered air is then delivered to the facepiece through a fixed length hose. The electrically powered fan drives the air from the filter cartridges, through the hose, and into the facepiece interior. Because the fan does the work required for air movement through the PAPR system, the user is able to comfortably receive a clean supply of air with little effort. Representative examples of known PAPRs are described in the following patents: U.S. Pat. No. 6,796,304 to Odell et al. U.S. Pat. No. 6,575,165 to Cook et al., U.S. Pat. No. 6,666,209 to Bennett et al., and U.S. Pat. No. 6,837,239 to Beizndtsson et al. 
         [0004]    Supplied air respirators that use a pressurized supply tank to provide clean air to the wearer are frequently referred to as self-contained breathing apparatus, or as “SCBAs”. SCBAs also have a hose that delivers clean air to the face piece from the clean air supply source. Examples of SCBAs are shown in the following publications: US 2005/0022817 A1, US 2004/0182395 A1, and US 2003/0111076 A1. 
         [0005]    While known supplied air systems have been very beneficial in supplying clean air to a worker, these known products have had one particular drawback: the hose that is used to deliver the air to the facepiece frequently gets caught on projections that exist in the workplace where the supplied air respirator is used. Supplied air respirators are designed to be used by persons of various sizes. Thus, the hose that extends from the filtering unit to the facepiece is sized to be long enough to accommodate persons that have long torsos. When a person who has a shorter torso, however, uses the same supplied air respirator, there is an extra hose length that dangles away from the user&#39;s body. This extra hose can become caught on articles that project into the area where the worker operates, making the user irritated and perhaps creating unsafe conditions in the work environment. Even more critically, a hose that is caught on an object may cause disengagement of the hose from either the face piece or the clean air supply source, thus compromising the breathing protection furnished by the system. The tangled hose also can cause adjacent objects to be knocked over or may cause the user to lose balance. 
         [0006]    The problem of extra hose length has been dealt with in the art providing the end users with hoses of various lengths. By offering more that one length of hose, the user can select the hose that is most suitable to them. This approach, however, also is disadvantageous because it requires the making and distribution of more than one hose. The need for multiple hoses increases the cost and complexity of the employer&#39;s health and safety program. And even when the users are furnished with more than one length hose, the user still has to chose the one nearest to their requirements, rather than having one of a precise length. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a supplied air respirator that may suitably comprise or consist essentially of: (a) a clean air supply source that is designed to be carried by a user of the supplied air respirator; (b) a face piece that is sized to fit at least over the user&#39;s nose and mouth; (c) a hose that extends from the supply source to the facepiece; and (d) a means for adjusting the length of the hose. 
         [0008]    The present invention differs from known supplied air respirators in that it has a hose length adjustment means. This feature is beneficial in that it allows persons of various heights and sizes to wear the same supplied air respirator without encountering hose entanglement problems. There is no need to have multiple sized hoses available for distribution, and each hose can be tailored to a precise length. A user of the inventive supplied air respirator can fashion the hose length to accommodate the length of their torso and thus preclude extra hose from dangling freely from their body. The inventive supplied air respirator thus provides greater convenience and safety to the end user and to other persons and things in the work environment. 
         [0009]    These and other advantages of the invention are more fully shown and described in the drawings and detailed description of this invention, where like reference numerals are used to represent similar parts. It is to be understood, however, that the drawings and description are for the purposes of illustration only and should not be read in a manner that would unduly limit the scope of this invention. 
       Glossary 
       [0010]    In describing this invention, the following terms are defined as set forth below: 
         [0011]    “adjustable length hose” means a hose that can be adjusted to a desired length; 
         [0012]    “breathing zone” means the portion of an interior gas space were clean air is inhaled by a wearer of a supplied air respirator; 
         [0013]    “clean air” means air (or other oxygen-containing gas) that has been filtered or that has otherwise been made safe to breathe for providing oxygen to a person; 
         [0014]    “clean air supply source” means an apparatus, such as a filtering unit or tank, that is capable of providing a supply of clean air (or oxygen) for person to safely breathe; 
         [0015]    “compliant face contacting member” means the portion of a face piece that is compliantly fashioned for allowing the mask body to be comfortably supported over a person&#39;s nose and mouth; 
         [0016]    “extends or extends from” means that the hose is located somewhere between the clean air supply source and the face piece to assist in allowing fluid communication to occur between such parts (the hose does not need to be directly attached at either end to such parts); 
         [0017]    “exterior gas space” means the ambient atmospheric gas space that surrounds a face piece when worn on a person and that ultimately receives exhaled gas after it exits the interior gas space of a mask; 
         [0018]    “face piece” means a device that is worn by a person over at least the respiratory passages (nose and mouth) of a person to help create an interior gas space separate from and exterior gas space; 
         [0019]    “filter cartridge” means a structure that includes a filter element and that is adapted for connection to or use in a filtering unit; 
         [0020]    “filtering unit” means the portion of a PAPR that is responsible for filtering ambient air and causing powered air movement; 
         [0021]    “hose” means a device that includes a conduit that has a fluid in permeable wall(s) through which air can travel for delivering clean air from a clean air supply source to a face piece; 
         [0022]    “interior gas space” means the space that exists between a mask body and a person&#39;s face when the mask is being worn; 
         [0023]    “mask body” means a structure that can fit at least over the nose and mouth of a person and that can help define an interior gas space separate from an exterior gas space; 
         [0024]    “powered air purifying respirator or PAPR” means a supplied air respirator that uses an external power source to deliver filtered air to the breathing zone of an interior gas space; 
         [0025]    “self-containing breathing apparatus” or SCBA means a supplied air respirator that has a pressurized bottle or tank in which a supply of clean air is stored; and 
         [0026]    “supplied air respirator” means a device that is capable of delivering a supply of clean air to a wearer of the device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is a perspective view of a powered air purifying respirator system  10  in accordance with the present invention; 
           [0028]      FIG. 2  is a plan view of an adjustable length hose  12  in accordance with the present invention, which hose  12  includes a sleeve  14  for fixing the tube length; 
           [0029]      FIG. 3  is a plan view of the adjustable length hose  12  of  FIG. 2 , including sleeves  14 ,  38  for covering the whole tube length; 
           [0030]      FIG. 4  is a plan view of an adjustable length hose  12 ′ that has a first portion  35  that is fixed in length or unextended; and 
           [0031]      FIG. 5  is a perspective on a self-contained breathing apparatus  50  in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    In describing preferred embodiments of the invention, specific terminology is used for the sake of clarity. The invention, however, is not intended to be limited to the specific terms so selected, and it is to be understood that each term so selected includes all technical equivalents that operate similarly. 
         [0033]    In the practice of the present invention, a powered air purifying respirator is provided that not as unwieldy as supplied air respirators heretofore known in the art. Unlike known supplied air respirators, which had hoses of uniform length and which could be too long for smaller users, the present invention furnishes the art with a supplied a respirator that has an adjustable length hose that reduces problems and costs associated with unnecessary hose length. 
         [0034]      FIG. 1  shows a powered air purifying respirator system  10  that includes an adjustable length hose  12  that has a sleeve  14  disposed over a tube  15  ( FIG. 2 ) through which air passes from a filtering unit  16  to a hood  18 . The filtering unit  16  has a fan  20  that is driven by an electric motor  22 . The fan  20  draws air through a filter element  24  and forces that filtered air into the interior gas space defined by the hood  18 . The fan  20  and the electric motor  22  are typically contained within a housing  26 . An electric switch  28  may be included in the circuit  31  to enable the PAPR  10  to be turned on and off The filter element is commonly contained within a filter cartridge housing  24 , which housing  24  is usually removably attached to the PAPR housing  26 . The PAPR housing  26  is commonly worn about the waist of the user and may be supported by a belt like the one shown in U.S. Patent Des. D501,288 to Taylor. Examples of a PAPR systems in which the present invention may be used are shown in U.S. Pat. Nos. 6,796,304 to Odell et al., 6,666,209 to Bennett et al., and 6,575,165 to Cook et al. Filter media that could be used to provide the wearer with a source of clean air include particulate filter media such as a webs of electrically charged fibers, particularly electrically charged microfibers—see U.S. Pat. Nos. 6,783,574 to Angadjivand et al., 6,119,691 to Angadjivand et al., and 5,472,600 to Ellefson et al. Alternatively, gaseous filters such as activated carbon filters can also be used to filter gaseous contaminants—see U.S. Pat. Nos. 6,344,071 B1 to Smith et al., 5,078,132 to Braun et al., and 4,443,354 to Eian. Filter elements that contain combinations of particulate and gaseous filter media may also be used in the filter cartridge(s). Multiple cartridges  24  also may be attached to the filtering unit  16 . The PAPR also could be provided with a sensor that tells the user when the flow rate has dropped below a specified level—see U.S. Pat. No. 6,615,828 to Petherbridge. In addition, a nonvolatile memory device may be associated with the filter element to keep a record of the filter element&#39;s usage—see U.S. Pat. No. 6,186,130 to Hogue. A system of calibrating air flow may also be used—see U.S. Pat. No. 6,666,209 B2 to Bennett et al. Although the PAPR shown in  FIG. 1  uses a hood  18  as a face piece that provides an interior gas space separate from an exterior gas space, a supplied air system in accordance with the present invention also could use a face mask that fits over wearer&#39;s nose and mouth (and optionally the eyes) or it could be a full containment suit—see, for example, U.S. Pat. No. 6,286,144 to Henderson et al. 
         [0035]      FIG. 2  shows a first embodiment of an adjustable length hose  12  in accordance with the present invention. Adjustable length hose  12  includes a first sleeve  14  and a tube  15 . The sleeve  14  is disposed over the tube  15  and has first and second ends  30  and  32 , respectively. The first end  30  is elasticated, that is, it can be resiliently stretched to accommodate and snugly grasp the first end  44  of the tube  15 . The sleeve end  30  also can be enlarged so that the tube  15  can be passed therethrough when assembling the device. The elastic nature of end  30  allows the sleeve  14  to fit snugly and tightly about the tube  15 . Any other method that permits adequate securement (physical, mechanical, or chemical) of the first sleeve end  30  to the first tube end  44  is contemplated under this invention. Besides mechanical gripping, the sleeve and could be, for example, adhered (using an adhesive) welded (using similar plastics) or fastened (using buttons or snaps) to the tube end. 
         [0036]    As  FIG. 2  shows, the opposing end  32  of sleeve  14  has a fastener  34  that allows the size of the sleeve opening at end  32  to be adjusted. The fastener  34  may be of the hook and loop type. The tube  15  may be made from a plastic material that is disposed over a spirally wound cord (see, for example, UK Patent 1,419,841). This kind of tube  15  is flexible and tends to exhibit resistance to axial compression. The tube  15  is formed in such a way that displays a tendency to expand in the axial direction if compressed from its naturally extended state. Conversely, if the tube is extended axially by exerting tension on it, it has a tendency to compress to return to its naturally extended state. The spirally wound cord provides shape and structural integrity to the tube  15  and allows it to be extended or compressed as needed. Alternatively, the tube could be a flexible, molded convoluted hose. The first end  44  of tube  15  can have, for example, a quick release swivel (Q. R. S.) adapter on it so that the hose  12  can be attached to the facepiece  18 . The opposing end  46  of the hose  12  can have a bayonet fitting for being secured to the filtering unit  16  ( FIG. 1 ). Other adapters or fittings may be used as desired. A portion of the tube  15  extends out from the interior of sleeve  14  to achieve the desired length. The fastener  34  is tightened around the tube  15  to preclude additional tube  15  from being extended (or withdrawn) from within the sleeve  14 . The length of the hose  12  is thus set. Because of its spirally-wound or helix, cordlike structure, the tube  15  has a tendency to expand axially to its full unencumbered length. By having the sleeve elastically secured to the tube at end  30  and by having the fastener  34  tightly secured about the tube at end  32 , the natural expansion of the tube  15  to its full-length can be retarded, and thus a desired length can be achieved. Although a mechanical fastener has been illustrated in the drawing, any technique for retarding hose expansion is contemplated under this invention. The sleeve  14 , for instance, can be secured to the tube  15  through use of essentially any gripping device such as an elastic fitting, an adhesive tape, a button, etc. or through the techniques mentioned above with respect to the first sleeve end. 
         [0037]      FIG. 3  shows that the adjustable length hose  12  may include a second sleeve  38  that has first and second ends  40  and  42 . The first end  40  is open and is sized to be sufficiently large to accommodate the first sleeve  14 . The second end  42  is elasticated to fit tightly about the tube  15  ( FIG. 2 ). The second sleeve  38  allows essentially the full length of the tube to be uniform in appearance and fully protected or covered by an outer sleeve member. 
         [0038]    To assemble the adjustable length hose  12  of the first embodiment of the present invention illustrated in  FIGS. 2 and 3 , the user starts by inserting the first end  44  of the tube  15  into the second end  32  of the first sleeve  14 . The tube  15  is drawn through the sleeve  14  until the elasticated end  30  fits tightly about the tube  15  and the first end  44  of the tube  15  projects axially from the sleeve  14 . The tube  15  is compressed within the sleeve  14  until the desired length is achieved. The fastener  34  is secured around the tube  15  at the desired length. The second end  46  of the tube  15  is placed in the open end  40  of the second sleeve  38 . The second end  42  of sleeve  38  is secured snugly about the second end  46  of the tube  15 . This can be achieved by making end  42  of tube  38  elasticated or by providing it with an adjustable fastener such as a hook and loop material. The hose  12  is thus adjusted to the desired length to fit the particular user, and the tube  15  is fully covered by the first and second sleeves  14  and  38 . The inventive adjustable length hose thus precludes excessive hose slack from occurring during use of the device by a smaller user. The annoyance and potential hazard that the slack creates is therefore reduced. To further reduce any opportunity for the hose to become inadvertently caught on an adjacent object, hardware could also be provided on the system, which hardware allows the hose to be held closely to the wearer&#39;s body when in use. 
         [0039]      FIG. 4  shows another method of providing an adjustable length hose  12 ′. In this embodiment, the tube  15 ′ is precluded from achieving its natural expansion through use of a bonding material  36 . Alternatively, the tube could be a molded, convoluted tube that expands axially, not naturally, but in response to tension (or pulling) by the user in the axial direction. The bonding material  36  may be in the form of a bead that extends as a line along the side of the tube  15 ′. The bonding material may extend along the full length of the side of the tube or along the side a distance sufficient to allow for expansion to accommodate users of various sizes. Two or more such bead lines may be disposed on the tube  15 ′ at 180° to each other. If desired, four bead lines could be used at 90° to each other. To achieve a hose  12 ′ of a desired length, the hose  15 ′ can be secured at one end and pulled at the other to break the bead lines  36 . When the hose  15 ′ has been extended to its desired length, the tension on the hose should cease so that the bead lines  36  are not broken further. The extended hose has two portions, a first compressed portion  35  and a second extended portion  37 . The desired length of the hose  12 ′ is thus achieved. 
         [0040]    In addition to the adjustment mechanisms illustrated and described above, other approaches are contemplated in connection with the present invention. Hose length could, for example, be adjusted using one or more the following techniques: (i) molded concertina or corrugations, like in a flexible drinking straw (see, U.S. Pat. Nos. 4,923,083, 4,078,692, and 3,346,187), which corrugations can be extended to a fixed length by pulling on the hose in the axial direction (ii) internal frictionally engaging mechanism that holds the internal structure of the hose in a compressed state or desired length via, for example, a ribbed outer edge that engages the internal structure of the tube material; (iii) internal adjustable length wire that extends through the central portion of the hose to connect opposing ends of the hose together (by varying the length of the wire thus controls the length of the breathing hose); (iv) telescopic device, (like an antenna) that can be adjusted by sliding the structured members to the correct length to suit the user; and (v) recoil hose stored under tension in a housing (the hose can be withdrawn from the housing to the desired length). Additionally, a brace and clip arrangement, which uses a flexible bracing arm, could be fixed on a portion of the compressed flexible hose. The clips would hold the brace in place to engage the hose at a particular corrugation(s) and keep the hose from extending between the braced points. 
         [0041]      FIG. 5  illustrates a SCBA system  50  that includes a facepiece  18 ′, a hose  52 , and a clean air supply source or tank  54 . The hose  52  is attached at its first end  44  to a fitting  58  that is attached to facepiece  18 ′. The second end of the hose  52  is secured to a fitting that is connected to the tank  54 . The tank  54  contains a pressurized supply of clean air for a wearer of the SCBA to breathe. The SCBA can be supported on a wearer&#39;s back through use of a harness  60  that includes straps and  62  and a belt  64 . The facepiece  18 ′ is adapted to fit over the nose, mouth, and eyes of the wearer and includes a harness  66  for supporting the facepiece  18 ′ on the wearer&#39;s head. The facepiece  18 ′ also has a window  68  through which the wearer can see the surrounding environment. The hose  52  can be adjusted in length using any one of the methods or systems described above. 
         [0042]    Although the above discussion describes clean breathable air being supplied by either a PAPR or SCBA, it may also be possible for the clean air to be supplied to the user&#39;s facepiece or headtop through an air regulator that supplies clear air to the user from either low or high pressure systems. In such a device, the user typically wears the regulator on a belt, the connection being made between the regulator and the facepiece/headtop by the hose described above. The regulator receives its air supply through a flexible adjustable length hose from either a lower or high pressure supply where low pressure typically comes from an air pump and where high pressure typically comes from an air compressor. A known regulator product has been marketed under the brand Flowstream™ by 3M, and such products have used wide bore hose (diameter≧about 3 cm, typically about 2 to 5 cm) for the connection between the regulator and the facepiece/headtop. For purposes of this invention, a hose that is connected to a clean air supply source through a regulator or other device is considered to be a hose that “extends from” the clean air supply source to the facepiece. 
         [0043]    Hoses that have been used in the past had a fixed length that would accommodate persons of essentially all sizes. This length is referred to in this document as the “conventional hose length” or “CHL”. The present invention is able to provide a variable or desired hose length “DHL”, which is equivalent to the CHL minus “X” where “X” is the amount of unneeded hose length, which would have created the extra slack in previously known systems. Conventional hose length typically was about 100 centimeters (cm). This hose length was provided to accommodate users of about 150 to 190 cm tall. For the smallest users, the minimum DHL is about 60 cm and therefore X=40 cm. The DHL for each user of the invention thus resides somewhere between the CHL of about 100 cm and about 60 cm. Thus, the hose of the invention is preferably adjustable from about 60 cm in length to 100 cm in length. 
         [0044]    The above discussion has for the most part described the hose adjustment apparatus as being a feature associated with or fitted to the hose itself, but this device may, however, also be associated or fitted to the facepiece. This could be accomplished by fashioning the facepiece with a device that allows for entry of the hose into the facepiece. Such a device could be particularly suitable for facepieces that are in the form of hoods or headtops (helmets). Likewise, the adjustment feature could also be associated with or fitted to the clean air supply source. 
         [0045]    This invention may take on various modifications and alterations without departing from its spirit and scope. This invention, accordingly, is not to be limited to the above described but is to be controlled by the limitations set forth in the following claims and any equivalents thereof. 
         [0046]    This invention also may be suitably practiced in the absence of any element not specifically disclosed herein. 
         [0047]    All patents and patent applications cited above, including those in the Background section, are incorporated by reference into this document in total. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                   
                 Part No. 
                 Item 
               
               
                   
                   
               
               
                   
                 10 
                 Powered air purifying respirator system 
               
               
                   
                 12 
                 Adjustable length hose 
               
               
                   
                 12′ 
                 Adjustable length hose 
               
               
                   
                 14 
                 Sleeve 
               
               
                   
                 15 
                 Tube 
               
               
                   
                 15′ 
                 Tube 
               
               
                   
                 16 
                 Filtering unit 
               
               
                   
                 18 
                 Hood 
               
               
                   
                 20 
                 Fan 
               
               
                   
                 22 
                 Electric motor 
               
               
                   
                 24 
                 Filter cartridge housing 
               
               
                   
                 26 
                 Housing 
               
               
                   
                 28 
                 Switch 
               
               
                   
                 30 
                 Elasticated first end 
               
               
                   
                 31 
                 Circuit 
               
               
                   
                 32 
                 Second end 
               
               
                   
                 34 
                 Fastener 
               
               
                   
                 35 
                 First compressed portion 
               
               
                   
                 36 
                 Bonding material 
               
               
                   
                 37 
                 Second extended portion 
               
               
                   
                 38 
                 Second sleeve 
               
               
                   
                 40 
                 First open end 
               
               
                   
                 42 
                 Second elasticated end 
               
               
                   
                 44 
                 First end of tube 
               
               
                   
                 46 
                 Second end of tube 
               
               
                   
                 50 
                 Breathing apparatus 
               
               
                   
                 52 
                 Hose 
               
               
                   
                 54 
                 Source tank 
               
               
                   
                 56 
               
               
                   
                 58 
                 Fitting 
               
               
                   
                 60 
                 Harness 
               
               
                   
                 62 
                 Straps 
               
               
                   
                 64 
                 Belt 
               
               
                   
                 66 
                 Harness 
               
               
                   
                 68 
                 Window