Patent Publication Number: US-2017360601-A1

Title: Convective system with fixation element

Description:
TECHNICAL FIELD 
     The present disclosure is related to convective devices and components to be used in a convective system for warming or cooling. 
     SUMMARY 
     At least some aspects of the present disclosure feature a tubular convective system, comprising: an inflatable tubular convective device, comprising: a tubular structure comprising a flexible material, wherein at least part of the tubular structure is air permeable; and a fixation element comprising a first ring, wherein the first ring is configured to secure a first part of the tubular convective device. 
     At least some aspects of the present disclosure feature A tubular convective system, comprising: an inflatable tubular convective device, comprising: a tubular structure comprising a flexible material, wherein at least part of the tubular structure is air permeable; and a fixation element comprising a flat element and a flexible element attached to the flat element proximate to a first end of the flexible element, wherein the flexible element is configured to secure a first part of the tubular convective device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, explain the advantages and principles of the invention. In the drawings, 
         FIG. 1A  illustrates a close-up view of one embodiment of a tubular convective device; 
         FIG. 1B  illustrates one embodiment of a convective system; 
         FIG. 2A  illustrates one example of a convective device; 
         FIG. 2B  illustrates the convective device illustrated in  FIG. 2A  bent at one of the air-guide devices; 
         FIGS. 3A and 3B  illustrate examples of convective systems; 
         FIGS. 3C-3F  illustrate some examples of a bundle of convective devices; 
         FIGS. 4A-4D  illustrate some examples of convective devices; 
         FIGS. 5A-5H  illustrate some examples of air-guide devices; 
         FIGS. 6A and 6B  illustrate some examples of tubular convective systems; 
         FIGS. 7A-7G  illustrate some examples of fixation elements; 
         FIGS. 8A-8G  illustrate some examples of hose manifolds; 
         FIG. 9A  illustrates a perspective view of one embodiment of a hose clamp; and 
         FIG. 9B  illustrates a side view of the hose clamp illustrated in  FIG. 9A ; 
         FIG. 9C  illustrates a side view of another embodiment of a hose clamp; 
         FIG. 10A  is a flattened view of a hose clamp toward the inner surface of an encircling element; 
         FIG. 10B  is a perspective view of the hose clamp illustrated in  FIG. 10A ; 
         FIG. 10C  is a side view of the hose clamp illustrated in  FIG. 10A ; 
         FIGS. 10D-10G  illustrate some example configurations of engaging components; 
         FIG. 11  illustrates an example of a convective system; 
         FIG. 12A  illustrates an example flowchart of using a tubular convective device; and 
         FIG. 12B  illustrates an example flowchart of making a tubular convective device. 
     
    
    
     In the drawings, like reference numerals indicate like elements. While the above-identified drawing, which may not be drawn to scale, sets forth various embodiments of the present disclosure, other embodiments are also contemplated, as noted in the Detailed Description. In all cases, this disclosure describes the presently disclosed disclosure by way of representation of exemplary embodiments and not by express limitations. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of this disclosure. 
     DETAILED DESCRIPTION 
     Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. 
     As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     Convective devices generally refer to a device distributing matter in gas state. For example, convective devices can receive a stream of pressurized, warmed air, inflate in response to the pressurized air, distribute the warmed air within a pneumatic structure, and emit the warmed air onto a body to accomplish such objectives as increasing comfort, reducing shivering, and treating or preventing hypothermia. In some embodiments, a convective device is a tubular convective device made from blown film. In such embodiments, the convective device does not use seals to form the pneumatic structure. In some cases, the convective device includes a homogeneous material to form the pneumatic structure. In some cases, at least part of the convective device has apertures of various shapes allowing pressured fluid to go through. In some embodiments, multiple tubular convective devices with or without tear perforations are formed in a roll. 
     In some embodiments, a convective device has a pneumatic structure that is formed by two layers, each layer including one or more sheets, and at least one of the layers is air permeable that allows air distribution. As used herein, “inflatable” refers to a structure which increases in volume when air or other gas is supplied at a pressure greater than atmospheric pressure to the interior of the structure. Typically these structures inflate at relatively low pressures such as pressures less than 100 mmHg, preferably at pressures less than 50 mmHg, more preferably at pressures less than 25 mmHg. In some cases, the volume of the inflatable section can increase by greater than 100%. Typically, the pneumatic structure is kinked or pinched off proximate to the bending area when the two portions are bent. In some cases, the convective device further includes an air-guide device in the pneumatic structure adapted to direct inflating medium to reduce pressure drop of the inflating medium at the bending area. As used herein, “in” is used to describe a spatial relationship of generally in the structure including at the edge of the structure. _For example, the convective device can include the air-guide device to help form one or more crease(s) when it is inflated, proximate to the air-guide device. 
     At least some embodiments of the present disclosure direct to a convective system including a convective device and a fixation element that can be used to facilitate placement of the convective device and/or facilitate form management of the convective device. For example, a fixation element having two ring elements can be used to hold two parts of a tubular convective device next to each other forming a blanket. As another example, a fixation element having an attachment device can be used to attach a convective device to a fixture, such as an operating (OR) bed, a hospital bed, an arm rest, or the like. 
     At least some embodiments of the present disclosure direct to a convective system including a convective device and a hose manifold to connect one hose end to more than one openings of the convective device. In some cases, the hose manifold can be used to connect two ends of a tubular convective device and thereby facilitate shape management. In some cases, the hose manifold provides more than one inputs of pressured inflating medium to allow uniform distribution of the inflating medium. In some cases of distributing heated air, a convective device with two openings connecting with a hose manifold can have a generally uniformed heat distribution. 
     At least some embodiments of the present disclosure direct to a hose clamp designed to be used with a convective device and a hose to improve air-tight connection and prevent slipping. In some embodiments, the hose clamp includes an encircling element matching the diameter of the hose and a grabbing component to facilitate user operation. In some cases, the hose clamp includes an engaging component disposed on the inner surface of the encircling element to improve gripping power of the hose clamp. The engaging component can include, for example, a plurality of engaging elements, bumps, raise-ups, or the like. In some implementations, the engaging elements are disposed in a pattern on the inner surface of the encircling element. In some cases, at least some of the engaging elements are disposed proximate to one end or both ends of the encircling element. 
     At least some embodiments of the present disclosure direct to a nozzle configuration designed to be used with a convective device to prevent slip and/or facilitate insertion into the convective device and a hose connecting to an inflation medium source. In some cases, the nozzle includes a hindrance device configured to prevent over insertion. In some cases, the nozzle has a piercing device configured to allow ease of use of the nozzle with the convective device. 
       FIG. 1  A illustrates a close-up view of one embodiment of a tubular convective device  100 A. The tubular convective device  100 A includes a blown film  110  forming a tube  115  when the blown film is inflated. The blown film  110  has a first portion  112  and a second portion  114 , where the two portions are separated longitudinally. In some cases, a plurality of apertures  130  are disposed only on the first portion  112  of the blown film  110 . In some other cases, a plurality of apertures  130  are disposed both on the first portion  112  and the second portion  114 . The blown film  110  can be made from suitable flexible polymer materials, for example, polyethylene, polyester, polypropylene (PP), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polyamide (PA), or the like. The blown film  110  is typically made from a homogeneous material. 
     In some embodiments, the plurality of apertures  130  cover at least 10% of surface area of the blow film  110 . In some cases, the plurality of apertures  130  cover at least 20% of surface area of the blow film  110 . In some cases, the plurality of apertures  130  cover at least 30% of surface area of the blow film  110 . Aperture density can vary depending on the size of the aperture and the pressure of inflating medium going into the tubular convective device  100 A. It is possible to have the film micro perforated or have large holes. The density of apertures can be associated with the diameter of the tubular convective device  100 A. In some cases, the apertures are disposed in a way such that a defused stream of air are provided to allow convective heat to transfer while minimizing impingement of the air stream on the body. The rate of heat transfer is determined by the air velocity and area of contact with the apertures. In some configurations, the diameter of the tubular conductive device increases, the percent of perforated surface area of the blown film decreases. In some embodiments, each of the plurality of apertures  130  has a same size and same geometry shape. In some cases, the plurality of apertures  130  can include apertures of different sizes. For example, the plurality of apertures  130  can have apertures of smaller sizes in the first portion of the tubular convective device and apertures of bigger sizes in the second portion of the tubular convective device. In some cases, the plurality of apertures  130  can have various shapes, for example, round, rectangular, oval, triangle, or the like. 
     In some embodiments, the first portion  112  and the second portion  114  are each a half portion. In some cases, the plurality of apertures  130  are only disposed on the first portion  112  of the blown film  110 . In some other cases, the plurality of apertures  130  are disposed on both the first portion  112  and the second portion  114  of the blown film  110 . In yet some other cases, the plurality of apertures are disposed on the second portion  114  of the blown film. In some implementations, the tubular convective device  100 A can have apertures of different densities at different parts, for examples, lower density apertures closer to the opening and higher density apertures farther from the opening. 
       FIG. 1B  illustrates one embodiment of a convective system  100 B having tubular convective devices  105  in a roll. In the embodiment illustrated, the convective system  100 B includes a perforation device  140 . The perforation device  140  has a plurality of pins  150  to punch apertures on to a series of connected convective devices  105 . In some cases, the perforation device  140  can have a pin density in the range of 1-20 per inch 2  (1550-31000 per m 2 ). In some cases, the convective devices  105  have existing apertures such that the perforation device  140  is not needed. In some cases, each of the two adjacent convective devices  105  have a separation perforation between adjacent convective devices  105 . In some other cases, no separation perforation exists between adjacent convective devices  105 , and each convective device  105  is cut when it is to be used. In such cases, the convective system  100 B may include a cutter and/or a measurement device for length determination. In some configurations, the tubular convective device can be cut to length, folded and packaged as well. 
       FIG. 2A  illustrates one example of a convective device  200 . The convective device has a first edge  220 , a second edge  230 , an inflatable channel  245 , and an air-guide device  210  configured to direct flow of inflating medium when the convective device is inflated and bent. In some cases, the air-guide device  210  includes a plurality of air-guide elements  212 . In some implementations, the air-guide device  210  is disposed proximate to the first edge  220  and/or the second edge  230 . In some cases, the air-guide elements  212  are disposed proximate one of the edges ( 220 ,  230 ) in a pattern. In some cases, the air-guide elements  212  disposed proximate to an edge ( 220  or  230 ) are disposed in equal spacing.  FIGS. 2B  illustrates the convective device  200  bent proximate to one of the air-guide elements  212 , where the convective device  200  is separated into a first portion  241  and a second portion  242  at the bending location. For example, the first portion  241  is bent along the direction  202  and the second portion  242  is bent along the direction  204 . In some cases, the air-guide device  210  is disposed proximate to the inflatable channel  245  connecting the first portion  241  and the second portion  242  but not disposed on the edge. In some cases, the air-guide device  210  and the air-guide element  212  is configured to facilitate forming creases at the edge of the air-guide device  210  when the convective device  210  is inflated is bent. In some cases, an air-guide element  210  including a guiding seal extending from an edge of the tubular convective device toward the tube structure. 
       FIGS. 3A and 3B  illustrate some examples of convective systems.  FIG. 3A  illustrates a convective system  300 A having a dispenser  310 A and a roll of convective devices  320 A. The convective device can use any configuration of the tubular convective devices described in the present disclosure. In some cases, the convective system  300 A includes a cutting device  330 A. In the example illustrated, the cutting device  330 A is attached to the dispenser  310 A.  FIG. 3B  illustrates another example of a convective system  300 B having a dispenser  310 B and a roll of convective devices  320 B. The dispenser  310 B is in a roller, which allow it to be moved around easily. 
       FIGS. 3C-3F  illustrate some examples of a bundle of convective devices that are connected.  FIG. 3C  illustrates a bundle of convective devices  300 C, where two adjacent convective devices have a line of weakness  310 C in between. The line of weakness  310 C allows the convective device to be separated from the bundle  300 C. In some cases, each of the convective device in the bundle  300 C has the same length. In some other cases, the convective devices in the bundle  300 C may have various length.  FIG. 3D  illustrates a bundle of convective devices  300 D, where two adjacent convective devices have a line of weakness  310 D and a close seal  320 D in between. In the example illustrated, the close seal  320 D is disposed proximate to the line of weakness  310 D. 
       FIG. 3E  illustrates a bundle of convective devices  300 E with an attachment device  330 E. In the example illustrated, the attachment device  330 E includes an adhesive strip running longitudinally across the bundle  300 E. In some cases, the attachment device  330 E is disposed proximate to the middle of the bundle  300 E. In some other cases, the attachment device  330 E may include two or more adhesive strips.  FIG. 3F  illustrates a bundle of convective devices  300 F with an attachment device  330 F. In the example illustrated, the attachment device  330 F includes a plurality of adhesive segments  340 F disposed in a pattern. In some cases, the plurality of adhesive segments  340 F are disposed in a generally equal spacing longitudinally. In some cases, the plurality of adhesive segments  340 F are disposed with different distances between adjacent segments. 
       FIGS. 4A-4D  illustrate some examples of convective devices.  FIG. 4A  illustrates a convective device  400 A made from blown film, where there are no seals at the longitudinal edges. A plurality of apertures  410 A are disposed on a portion or the entire body of the convective device  400 A.  FIG. 4B  illustrates a convective device  400 B including two layers  420 B and  422 B, and the two layers  420 B and  422 B are sealed at longitudinal edges  440 B to form a pneumatic structure. In some cases, one layer  420 B includes a plurality of apertures  410 B, where the apertures  410 B can be disposed before or after the two layers are sealed. In some other cases, one or both layers include apertures or air permeable material.  FIG. 4C  illustrates a convective device  400 C includes one layer  420 C that is sealed at its longitudinal edge  440 C. In some cases, a plurality of apertures  410 C are disposed on a portion or the entire body of the convective device  400 C. Typically, the one or more layers of the convective device are made from flexible materials. 
       FIG. 4D  is a top plane view of one embodiment of a convective device  400 D having more than one inflatable channels. In this embodiment, the convective device  400 D has a flexible first layer  407 D, a flexible second layer (not visible in this view), and two openings  430 D. In some cases, the flexible first layer  407 D has air permeable surface. The flexible second layer joining the first layer by a seal  406 D around a common periphery to form a pneumatic structure  440 D, where the pneumatic structure  440 D has a first edge  441 D and an opposing second edge  442 D. The pneumatic structure  440 D has a first portion  443 D, a second portion  444 D, and an inflatable channel  445 D connecting the first portion  443 D and the second portion  444 D, where the first portion and the second portion are generally extending along a same line, for example. The inflatable channel  445 D can be formed, for example, by seals  408 D. In some cases, the convective device  400 D is an inflatable upper body blanket suitable to cover the upper body of a person with arms extending in a clinical position in its original configuration. 
     In some embodiments, the convective device  400 D includes at least one opening  430 D into the pneumatic structure  440 D. The opening  430 D can be in any form that allows an inflating medium source (not illustrated) to connect and provide inflating medium to inflate the pneumatic structure  440 D, for example, a sleeve opening at the edge as illustrated in  FIG. 4D . As other examples, the opening  430 D can include one or more inlet ports, cuffs, ports with stiff collars, sleeve openings at the edge, or the like. In one embodiment, the two openings  430 D can connect a hose manifold that have two outlet connectors and one hose connector configured to connect to the inflating medium source, which is described in details below. 
     In some embodiments, the convective device  400 D includes an air-guide device  420 D. In some cases, the air-guide device  420 D is disposed proximate to the second edge  442 D of the pneumatic structure  440 D and between the first portion  443 D and the second portion  444 D, which is adapted to direct flow of inflating medium between the two portions, especially when the first portion  443 D and/or the second portion  444 D are bent. In some cases, the air-guide device  420 D is disposed between the first portion  443 D and the second portion  444 D. In some cases, the air-guide device  420 D is configured to facilitate forming creases at the edge of the air-guide device when the configurable convective device  400 D is inflated and at least one of the first portion and the second portion are rearranged such that the inflatable channel  445 D is bent. 
     In some cases, the air-guide device  420 D is disposed at a center portion of the pneumatic structure that has a starting point at a distance of ¼ of the width from one end and an ending point at a distance of ¼ of the width from the other end. In some cases, the air-guide device  420 D is disposed at a center portion of the pneumatic structure that has a starting point at a distance of ⅖ of the width from the one end and an ending point at a distance of ⅖ of the width from the other end. In some cases, the air-guide device  420 D is disposed at the portion of the inflatable channel  445 D that is closer to the second edge  442 D and farther from the first edge  441 D. In some embodiments, the air-guide device  420 D comprises a guiding seal extending from the second edge  442 D and toward the pneumatic structure  440 D. In the embodiment as illustrated, the air-guide device  420 D comprises two guiding seals  421 D and  422 D, each guiding seal extending from the second edge  442 D and toward the pneumatic structure  440 D. In some cases, the two guiding seals ( 421 D,  422 D) are directed to a different portion (the first portion  443 D or the second portion  444 D) of the pneumatic structure  440 D. In some cases, the two guiding seals ( 421 D,  422 D) are generally perpendicular with each other. 
     In some embodiments, each layer of a convective device may include one or more sheets of materials. In some implementations, a layer of a convective device may include an underside sheet formed from a flexible, fibrous, preferably non-woven structure composed of polymeric materials capable of bonding to an upper side sheet of a heat-sealable polymeric material. For example, the underside sheet may be a non-woven, hydroentangled polyester material and the upper side layer may include a polyolefin such as a polypropylene film which is extrusion-coated, thermally laminated, or adhesively laminated onto the polyester layer. Alternatively, the underside sheet may comprise a non-woven, paper-based material to which the upper side layer, including either a polyethylene, polyester, or polypropylene film, has been glue laminated. In one embodiment, the upper side and underside sheets can be made with a stratum of absorbent tissue paper prelaminated with a layer of heat-sealable plastic. In some cases, both the first layer and the second layer can include a same polymer material. 
     In some embodiments, a first layer includes the upper side sheet and the underside sheet, and a second layer comprises the same material as the upper side sheet of the first layer. The second layer thus may include a sheet of plastic bonded to the plastic upper side of the second layer. It is preferably attached by a continuously-running web process including stations that provide an interruptible heat-sealing process. This interruptible heat sealing process can be controlled to form elongated heat seals (e.g.,  408 D in  FIG. 4D ) that define the inflatable channels therebetween. The seals can be formed as continuous air impervious seals or discontinuous air permeable seals. The interruptible heat sealing process can be used to form the continuous seams, one of which is the seam at the peripheral of the first layer and the second layer. In some cases, the interruptible heat sealing process can be used to form the discontinuous heat seals. In some cases, absorbent material can be applied to the convective device, for example, applied as a single material layer. The absorbent material can be bonded to the upper plastic layer by heat processing or by adhesive bonding. 
     In some embodiments, the convective device is enabled to bathe a patient in the thermally controlled inflating medium introduced into the convective device  100 , when inflated, via an air permeable layer. A layer can be air permeable using various materials or mechanical structures, for example, air-permeable materials, apertures, interstices, slits, or the like. In some implementations of an air permeable sheet with apertures, the density of apertures can vary among areas and/or inflatable sections. 
     In some embodiments, one or two layers of a convective device are made from a polyolefin non-woven extrusion coated, each with a coating of polypropylene on one side. In some other embodiments, the one or more layers can be poly lactic acid spunbond with polyolefin based extrusion coat. One of the layers may have holes formed by punching, slitting, or cutting to permit the flow of pressurized inflating medium from the inflated section through the layer. In some cases, the holes can be opened through both layers. In some cases, when the convective device is assembled, the polypropylene-coated side of the first layer is sealed to the polypropylene-coated side of the second layer at the periphery, and at the one or more locations to form the construction. The sealing process can use various techniques, for example, ultrasonic welding, radio frequency welding, heat sealing, or the like. Alternatively, the first layer and second layer may each include a laminate of polypropylene and polyolefin web with holes formed in at least one of the layers to support passage of pressurized air. In yet another embodiment, at least one of the layers can use air permeable material, for example, spunbond-meltblown-spunbond (SMS) nonwoven material, or the like. 
       FIGS. 5A-5H  illustrate some examples of air-guide devices/air-guide elements.  FIG. 5A  illustrates an air-guide device or air-guide element  500 A including two guiding seals  502 A and  504 A, where both seals are extending from a periphery seal  510 A.  FIG. 5B  illustrates an air-guide device or air-guide element  500 B including one guiding seal  502 B extending from a periphery seal  510 B.  FIG. 5C  illustrates an air-guide device or air-guide element  500 C including a continuous seal  502 C, in a curve shape, starting from a first position  511 C on a periphery seal  510 C and ending at a second position  512 C on the periphery seal  510 C different from the first position  511 C. When the convective device is inflated, the air-guide device  500 C can facilitate forming a number of creases proximate to the air-guide device  500 C in the convective device where the convective device is bent.  FIG. 5D  illustrates an air-guide device or air-guide element  500 D including a continuous seal  502 D starting from a first position  511 D on a periphery seal  510 D and ending at a second position  512 D on the periphery seal  510 D different from the first position  511 D. 
       FIG. 5E  illustrates an air-guide device or air-guide element  500 E including three guiding seals  502 E extending from a periphery seal  510 E.  FIG. 5F  illustrates an air-guide device or air-guide element  500 F including one seal  502 F disposed proximate to but not touching a periphery seal  510 F.  FIG. 5G  illustrates an air-guide device or air-guide element  500 G including one continuous seal  502 G in a closed shape or a closed shape seal  502 G disposed proximate to but not touching a periphery seal  510 G. The seal  502 G can be in any closed shapes, for example, such as circle, oval, square, rectangle, polygon, or the like. In some cases, the seal  502 G is no more than one inch (2.54 cm) from the periphery seal  510 G. In some cases, the seal  502 G is no more than two inches (5.08 cm) from the periphery seal  510 G. 
       FIG. 5H  illustrates an example of air-guide device  500 H that is an integrated part of or proximate to a periphery seal  510 H. The air-guide device  500 H includes a zigzag portion  502 H between first and second portions of the pneumatic structure as illustrated in  FIGS. 1A, 2A and 3A , for example, such that the zigzag portion  502 H is adapted to facilitate the generation of a number of distributed creases and direct inflation medium to reduce pressure drop of the inflation medium at the bending area when the configurable convective device is inflated and at least one of the first portion and the second portion are rearranged such that the inflatable channel between the two portions is bent. In some cases, the zigzag portion  502 H is integrated with the periphery seal  510 H. In some cases, the entire periphery seal can be zigzagged. In some cases, the zigzag portion  502 H is in a wavy shape. In some cases, the zigzag portion is a in a curve shape, square saw-tooth, triangular saw-tooth, or similar shape, or combination of shapes. 
     In some embodiments, a convective system may include one or more fixation elements and/or hose manifold, as illustrated in  FIG. 6A . In the example illustrated, a convective system  600 A includes an inflatable tubular convective device  610 , two fixation elements  620 , and a hose manifold  630  configured to connect to a hose  635 . The convective system  600  can be used with a bed  605 . The tubular convective device  610  can be used on a person  606 , for example, over the upper body of the person  606 , over the lower body of the person  606 , over the entire body of the person, or alongside the person  606 . The fixation element  620  can be used to manage the disposition and shape of the convective device  610 . For example, the convective device can be formed into a generally rectangular shape. As another example, the convective device can be formed into a “U” shape to be disposed alongside the person  606 . In some cases, the fixation element  620  includes a first ring, where the first ring is configured to secure a first part of the tubular convective device  610 . In the embodiment illustrated in  FIG. 6A , the fixation element  620  further includes a second ring connected to the first ring, and wherein the second ring is configured to secure a second part of the tubular convective device. 
     In some cases, the convective device  610  can have two openings  612 . In some cases, the hose manifold  630  is rigid. The hose manifold  630  includes a hose connector  633  configured to connect to a hose and two outlet connectors  632  configured to connect to the two openings  612  of the convective device  610  respectively, where the hose connector  633  and the two output connectors  632  are in fluid connection. 
       FIG. 6B  illustrates another example of a convective system  600 B. In the example illustrated, a convective system  600 B includes an inflatable tubular convective device  610 , and a hose manifold  630  configured to connect to a hose (not illustrated). In this embodiment, the hose manifold  630  includes two expandable outlet connectors  632  that can be connected to two openings  612  of the tubular convective device  610  and a hose connector  633  to connect to the hose. 
       FIGS. 7A-7G  illustrate some examples of fixation elements.  FIG. 7A  illustrates a fixation element  700 A includes a first ring  710  and a second ring  720  connected to the first ring  710 .  FIG. 7B  illustrates a fixation element  700 B includes a first ring  710  and a second ring  720  connected to the first ring  710 . In the example as illustrated, the first ring  710  and/or the second ring  720  has an opening  730 . In some cases, the width of the opening  730  is less than the diameter of the corresponding ring. 
       FIG. 7C  illustrates a fixation element  700 C includes a first ring  710  and a second ring  720  connected to the first ring  710 , and one or two generally flat elements  740 , which can be used for placement.  FIG. 7D  illustrates a fixation element  700 C includes a first ring  710  and a second ring  720  connected to the first ring  710 , and an attachment element  750  configured to attach to a fixture, for example, such as an operation bed, an arm rest, a hospital bed, or the like. In the example illustrated, the attachment element  750  includes a generally “L” shape part. 
       FIG. 7E  illustrates a fixation element  700 E including a rigid flat element  710 E and a flexible element  720 E configured to secure a part of a convective device. In some cases, the flexible element  720 E is attached to the flat element  710 E on one end  721 E and the flat element  710 E is configured to releasably attach to the flexible element  720 E proximate to the other end  722 E. For example, the flat element  710 E has a slit  712 E allowing the other end  722 E of the flexible element  720 E to slide in. In some other cases, the flexible element  720 E can be attached to the flat element  710 E on one end  721 E and having a heavy part at the other end  722 E such that the flexible element  720 E can wrap around a convective device. In some cases, the flexible element  720 E can be of any shapes, for example, a tube, a string, a flat string, a strap, or the like. In some implementations, the flat element  710 E can be inserted into an arm rest  770 E of an OR bed. In such implementations, the flat element  710 E can have attachment elements (not shown) for placement, such as adhesive stripes, hook and loop, repositionable adhesives, mechanical reclosable fasteners, or the like. 
       FIG. 7F  illustrates an example of a fixation element  700 F includes a first ring  710  and an attachment element  750  configured to attach to a fixture, for example, such as an operation bed, an arm rest, a hospital bed, or the like. In the example illustrated, the attachment element  750  includes a generally “L” shape part.  FIG. 7G  illustrates an example of a fixation element  700 G having a ring  710 G and a strap  720 G. In some cases, the strap  720 G can have an attachment element  721 G on one end and a mating attachment element  722 G on the other end. For example, the attachment elements ( 721 G,  722 G) can include, for example, hook and loop, adhesive strip, or the like. 
       FIGS. 8A and 8B  illustrate two examples of hose manifolds used with tubular convective devices.  FIG. 8A  illustrates a hose manifold  800 A including two outlet connectors  810 A and  820 A and a hose connector  830 A configured to connect to a hose. As illustrated, the two outlet connectors  810 A and  820 A are generally parallel and open toward generally same directions. Each outlet connector ( 810 A,  820 A) is connected with one end of a tubular convective device  805 .  FIG. 8B  illustrates a hose manifold  800 B including two outlet connectors  810 B and  820 B and a hose connector  830 B configured to connect to a hose. The two outlet connectors  810 B and  820 B open toward generally opposite directions. Each outlet connector ( 810 B,  820 B) is connected with one end of a tubular convective device  805 . In some embodiments, the outlet connectors  810 B and  820 B of a manifold can be connected to two openings of a convective device. 
       FIGS. 8C-8E  illustrate another example of a hose manifold  800 C, where  FIG. 8C  is a perspective view,  FIG. 8D  is a top view, and  FIG. 8E  is a side view. The manifold  800 C includes two outlet connectors  810 C and  820 C and a hose connector  830 C configured to connect to a hose. In some embodiments, the hose manifold  800 C further includes an attachment element  840 C configured to attach to a fixture. In some cases, the attachment element may include a generally “L” shape part. In the example illustrated, the attachment element  840 C can include a “V” or triangle shape component, which can be inserted into a mating component (e.g.,  860 C) on the fixture. The cross-section of outlet connectors  810 C and/or  820 C can have any shapes, for example, a round shape, a triangular shape, an oval shape, a polygon shape, or the like. In some cases, the outlet connectors  810 C and/or  820 C can be slanted along a slope  815 C. In some cases, the slope  815 C is from the longest edge  811 C toward the opposing tip  813 C. In the example illustrated, the generally triangular shape opening and the slanted configuration may allow the connector to be easily inserted. In some embodiments, the connectors  810 C and/or  820 C can include one or more flexible flaps  850 C that can prevent the connector from slipping out. In some cases, the flexible flap  850 C can present leakage. An alternative structure to the flexible flap could also include a ridge or flange of flexible material with encircle the entire circumference of the hose manifold. Suitable materials of construction for the flexible flaps  850 C, or the flexible ridge or flange structure would include soft or rigid thermoplastic elastomers such as polyesters, polyurethanes, polyamides, or polyolefin blends; or thermoset elastomers such as natural and synthetic rubbers such as latex, nitrile, millable polyurethane, silicone, butyl and neoprene. 
       FIGS. 8F and 8G  illustrate another example of a manifold  800 F. The manifold  800 F includes two outlet connectors  810 F and  820 F and a hose connector  830 F configured to connect to a hose. One or both of the outlet connector ( 810 F,  820 F) can include an expandable element  815 F. Expandable element  815 F could be constructed of common thermoplastic or thermoset elastomers materials with an optional metal or rigid plastic coil to protect and reinforce expandable element from kinking or pinching that would close off the flow of inflating medium.  FIG. 8G  illustrates the expandable element  815 F being extended such that the outlet connectors  810 F and  820 F are further apart. In some cases, the expandable element  815 F can be expanded and retain the extension. In some embodiments, the expandable element  815 F can be bent or rotated to an angle. 
     In some cases of using a convective device, a hose clamp may be used to maintain adequate air-tight connection between the hose and the convective device.  FIG. 9A  illustrates a perspective view of one embodiment of a hose clamp  900 ; and  FIG. 9B  illustrates a side view of the hose clamp  900 . In the embodiment illustrated, the hose clamp  900  includes an encircling element  910 , an optional grabbing component  920  extending from the encircling element, and an optional engaging component  930  disposed on or integrated with the encircling element. The encircling element  910  includes having an inner surface  912  and an opposing outer surface  914 . In some cases, the central angle  950  of the encircling element  910  is greater than 180 degree. In some cases, the central angle  950  of the encircling element  910  is smaller than 360 degree. 
     In some embodiments, the engaging component  930  includes a plurality of engaging elements  935 . In some implementations, the engaging component  930  includes a pattern of engaging elements  935 , for example, a pattern of a line, a pattern of a wave, a pattern of higher density proximate to the end, or the like. The encircling element  910  has a first end  941 , a second end  942 , and a middle portion  945 . In some cases, the encircling element  910  can be semi-rigid or rigid. The encircling element  910  can include materials, for example, polycarbonate, polyester, polyethylene, nylon, acrylonitrile butadiene styrene (ABS), polypropylene, polyvinyl chloride (PVC), and/or the like. In some cases, the grabbing component  920  and the engaging component  930  can include the same materials as the encircling element  910 . In some other cases, the grabbing component  920  and the engaging component  930  can include different materials as the encircling element  910 . In some cases, the engaging components can have a material the same as or different from the material used for the encircling element  910 . In some cases, the engaging component  930  can use soft materials, for example, urethane, thermoplastic materials, thermoplastic elastomers (TAE), or the like. The engaging elements  935  can have any shapes, for example, cylinder, half sphere, prism, hexagonal prism, trapezoidal prism, cube, cuboid, cone, pyramid, or the like. 
       FIG. 9C  illustrates a front view of another embodiment of a hose clamp  900 C. The hose clamp  900 C includes an encircling element  910 , an optional grabbing component  920 C extending from the encircling element, and an optional engaging component  930  disposed on or integrated with the encircling element. Components with same labels can have same or similar configurations, compositions, functionality and/or relationships as the corresponding components in  FIGS. 9A and 9B . In the embodiment illustrated, the grabbing component  920 C includes two elements  921  and  922 . 
       FIG. 10A  is a flattened view of a hose clamp  1000  toward the inner surface of an encircling element;  FIG. 10B  is a perspective view of the hose clamp  1000 ; and  FIG. 10C  is a side view of the hose clamp  1000 . The hose clamp  1000  includes an encircling element  1010 , an optional grabbing component  1030  and an optional engaging component  1020 A. The encircling element  1010  has a first end  1012 , a second end  1014 , and a middle portion  1016 . The engaging component  1020 A can include one or more sets of engaging elements  1025 . In one embodiment, the engaging component  1020 A includes a set of engaging elements  1022  disposed proximate to the first end  1012  of the encircling element  1010 . In the example illustrated in  10 A, the set of engaging elements  1022  includes multiple engaging elements  1025  (with three illustrated) disposed in a line, where the engaging elements  1025  are disposed in a line slanted from the first end  1012 . In some embodiments, the engaging component  1020 A includes a set of engaging elements  1024  disposed proximate to the second end  1014  of the encircling element  1010 . In the example illustrated in  FIG. 10A , the set of engaging elements  1024  includes multiple engaging elements  1025  disposed in a line, where the engaging elements  1025  are disposed in a line slanted from the second end  1014 . In some embodiments, the engaging component  1020 A includes a set of engaging elements  1026  disposed in the middle portion  1016 . In some cases, the set of engaging elements  1026  includes at least three engaging elements  1025  disposed in a line. 
       FIGS. 10D-10G  illustrate some example configurations of engaging components.  FIG. 10D  illustrates an engaging component  1020 D includes three elongated engaging elements  1022 D,  1024 D, and  1026 D that are generally parallel with each other and extend proximate the first end  1012  to the second end  1014 .  FIG. 10E  illustrates an engaging component  1020 E includes three sets of engaging elements ( 1022 E,  1024 E, and  1026 E). The set of engaging element  1022 E is proximate to the first end  1012  and is in a line. The set of engaging element  1024 E is proximate to the second end  1014  and is generally in a line. The set of engaging element  1026 E is proximate to the center portion  1016  and is generally parallel to either end. 
       FIG. 10F  illustrates an engaging component  1020 F including three engaging elements ( 1022 F,  1024 F, and  1026 F). The engaging element  1022 F is disposed proximate to the first end  1012 , the engaging element  1024 F is disposed proximate to the second end  1014 , and the engaging element  1026 F is disposed at the center portion  1016 . The three engaging elements  1022 F,  1024 F, and  1026 F, as illustrated, may be disposed at locations with different distances to the edges of the encircling element  1010 .  FIG. 10G  illustrates an engaging component  1020 G including multiple engaging elements  1025 . In one embodiment, the engaging elements  1025  can be disposed discontinuously across the encircling element  1010  from the first end  1012  to the second end  1014 . 
       FIG. 11  illustrates an example of a convective system  1100 . The convective system  1100  includes a tubular convective device  1110 , a hose manifold  1120 , and one or more hose clamps  1130 . The tubular convective device, the hose manifold, and the hose clamp can use any one of the configurations of respective devices and components described in the present disclosure. The tubular connective device  1110  is connected to the hose manifold  1120  and the hose clamp  1130  is applied on top of the connection portion of the tubular connective device  1110  and the hose manifold  1120  to maintain the generally airtight connection. In the example illustrated, the hose manifold  1120  includes two outlet connectors  1135 . 
       FIG. 12A  illustrates an example flowchart of using a tubular convective device. First, open a tubular convective device, or tear off from a roll (step  1210 A). Place a tubular convective device on or around a person (step  1220 A). Next, connect one end of the tubular convective device to a hose or an outlet connector hose manifold (step  1230 A). Optionally, in the case of using a hose manifold, connect another end of the tubular convective device to another outlet connector of the hose manifold (step  1240 A). Optionally, place a hose clamp on the connection portion between the hose or hose manifold and the tubular convective device (step  1250 A). Turn on the inflating medium source (step  1260 A). Optionally, use a fixation element with the tubular convective device (step  1270 A), for example, to keep the tubular convective device close to the person or cover a specific part of the person. 
       FIG. 12B  illustrates an example flowchart of making a tubular convective device. Place a roll of blown film into the machine (step  1210 B). Place an end of the roll into the feeder (step  1220 B). Optionally, start the perforation device (step  1230 B). Perforate the blown film with a predefined configuration (step  1240 B). Optionally, cut the perforated blown film at a predefined length (step  1250 B). In some cases, a measurement device can be used. The measurement device can be, for example, a ruler, one or more markers indicating various length, or the like. In some cases as illustrated in  FIG. 1B , the blown film is laid flat to feed into the machine, such that the perforation is done on the two layers of film. In some cases, the perforation device has a density of at least 1500 pins per square meter. 
     Exemplary Embodiments 
     Item A1. A tubular convective system, comprising:
         an inflatable tubular convective device, comprising:
           a tubular structure comprising a flexible material, wherein at least part of the tubular structure is air permeable;   
           a fixation element comprising a first ring, wherein the first ring is configured to secure a first part of the tubular convective device.       

     Item A2. The tubular convective system of Item A1, wherein the fixation element further comprises a second ring connected to the first ring, and wherein the second ring is configured to secure a second part of the tubular convective device. 
     Item A3. The tubular convective system of Item A1 or A2, wherein the first ring has an opening. 
     Item A4. The tubular convective system of Item A3, wherein a width of the opening is less than a diameter of the first ring. 
     Item A5. The tubular convective system of any one of Item A1-A4, wherein the fixation element further comprises a generally flat element. 
     Item A6. The tubular convective system of any one of Item A1-A5, wherein the fixation element further comprises an attachment element configured to attach to a fixture. 
     Item A7. The tubular convective system of Item A6, wherein the attachment element comprises a generally “L” shape part. 
     Item A8. The tubular convective system of any one of Item A1-A7, wherein the tubular convective device further comprises an air-guide element configured to direct flow of inflating medium when the tubular convective device is bent. 
     Item A9. The tubular convective system of Item A8, wherein the air-guide element comprises a guiding seal extending from an edge of the tubular convective device toward the tube structure. 
     Item A10. The tubular convective system of Item A8, wherein the air-guide element is disposed within the tube structure. 
     Item A11. The tubular convective system of Item A8, wherein the air-guide element is configured to facilitate forming creases at the edge of the air-guide element when the tubular convective device is inflated and bent. 
     Item A12. The tubular convective system of any one of Item A1-A11, wherein the tubular structure comprises a blown film. 
     Item A13. The tubular convective system of Item A12, wherein the tubular structure further comprises a plurality of apertures disposed on the blown film. 
     Item A14. The tubular convective system of Item A13, wherein the tubular structure comprises a first portion and a second portion separated from the first portion longitudinally, and wherein the plurality of apertures are only disposed on the first portion of the tubular structure. 
     Item A15. A tubular convective system, comprising:
         an inflatable tubular convective device, comprising:
           a tubular structure comprising a flexible material, wherein at least part of the tubular structure is air permeable;   
           a fixation element comprising a flat element and a flexible element attached to the flat element proximate to a first end of the flexible element, wherein the flexible element is configured to secure a first part of the tubular convective device.       

     Item A16. The tubular convective system of Item A15, wherein the flat element is configured to releasably attach to the flexible element proximate to a second end of the flexible element. 
     Item A17. The tubular convective system of Item A16, wherein the flat element comprises a slit allowing the flexible element to slide in. 
     Item A18. The tubular convective system of any one of Item A15-A17, wherein the flexible element comprises a heavy component proximate to a second end. 
     Item A19. The tubular convective system of any one of Item A15-A18, wherein the flat element is configured to be secure to a fixture. 
     Item A20. The tubular convective system of any one of Item A15-A19, wherein the flexible element comprises at least one of a tube, a string, and a strap. 
     Item A21. The tubular convective system of any one of Item A15-A20, wherein the tubular convective device further comprises an air-guide element configured to direct flow of inflating medium when the tubular convective device is bent. 
     Item A22. The tubular convective system of Item A21, wherein the air-guide element comprises a guiding seal extending from an edge of the tubular convective device toward the tube structure. 
     Item A23. The tubular convective system of Item A21, wherein the air-guide element is disposed within the tube structure. 
     Item A24. The tubular convective system of Item A21, wherein the air-guide element is configured to facilitate forming creases at the edge of the air-guide element when the tubular convective device is inflated and bent. 
     Item A25. The tubular convective system of any one of Item A15-A24, wherein the tubular structure comprises a blown film. 
     Item A26. The tubular convective system of Item A25, wherein the tubular structure further comprises a plurality of apertures disposed on the blown film. 
     Item A27. The tubular convective system of Item A26, wherein the tubular structure comprises a first portion and a second portion separated from the first portion longitudinally, and wherein the plurality of apertures are only disposed on the first portion of the tubular structure. 
     Item B1. A convective system, comprising:
         an inflatable convective device having a pneumatic structure and two openings into the pneumatic structure, wherein at least part of the convective device is air permeable;   a hose manifold comprising:
           a hose connector configured to connect to a hose,   two outlet connectors configured to connect to the two openings respectively,   wherein the hose connector and the two output connectors are in fluid connection.   
               

     Item B2. The convective system of Item B1, wherein the two outlet connectors open toward generally opposite directions. 
     Item B3. The convective system of Item B1 or B2, wherein the two outlet connectors are generally parallel and open toward generally same directions. 
     Item B4. The convective system of any one of Item B1-B3, wherein the hose manifold further comprises an attachment element configured to attach to a fixture. 
     Item B5. The convective system of Item B1, wherein at least one of the two outlet connectors further comprises a flexible flap configured to prevent slipping. 
     Item B6. The convective system of any one of Item B1-B5, wherein at least one of the two outlet connectors is slanted. 
     Item B7. The convective system of any one of Item B1-B6, wherein at least one of the two outlet connectors comprises a generally triangular opening. 
     Item B8. The convective system of any one of Item B1-B7, wherein at least one of the two outlet connectors comprises a generally round opening. 
     Item B9. The convective system of any one of Item B1-B8, wherein at least one of the two outlet connectors comprises an expandable element. 
     Item B10. The convective system of any one of Item B1-B9, wherein the hose manifold is rigid. 
     Item B11. The convective system of any one of Item B1-B10, wherein the inflatable convective device further comprises an air-guide element configured to direct flow of inflating medium when the inflatable convective device is bent. 
     Item B12. The convective system of Item B11, wherein the air-guide element comprises a guiding seal extending from an edge of the inflatable convective device toward the pneumatic structure. 
     Item B13. The convective system of Item B11, wherein the air-guide element is disposed within the pneumatic structure. 
     Item B14. The convective system of Item B11, wherein the air-guide element is configured to facilitate forming creases at the edge of the air-guide element when the inflatable convective device is inflated and bent. 
     Item B15. The convective system of any one of Item B1-B14, wherein the inflatable convective device is a tubular convective device. 
     Item B16. The convective system of Item B15, wherein the tubular convective device comprises a blown film. 
     Item B17. The convective system of Item B16, wherein the tubular convective device further comprises a plurality of apertures disposed on the blown film. 
     Item B18. The convective system of Item B17, wherein the tubular convective device comprises a first portion and a second portion separated from the first portion longitudinally, and wherein the plurality of apertures are only disposed on the first portion of the tubular structure. 
     Item C1. A tubular convective device, comprising:
         a blown film forming a tube when inflated, the blown film having a first portion and a second portion, wherein the first portion and the second portion are separated longitudinally, and   a plurality of apertures disposed on the first portion of the blown film.       

     Item C2. The tubular convective device of Item C1, wherein the first portion and the second portion are each half portion. 
     Item C3. The tubular convective device of Item C1 or C2, wherein the plurality of apertures are only disposed on the first portion of the blown film. 
     Item C4. The tubular convective device of any one of Item C1-C3, wherein the plurality of apertures are disposed on the second portion of the blown film. 
     Item C5. The tubular convective device of any one of Item C1-C4, further comprises: an air-guide element configured to direct flow of inflating medium when the tubular convective device is bent. 
     Item C6. The tubular convective device of Item C5, wherein the air-guide element comprises a guiding seal extending from an edge of the tubular convective device toward the tube structure. 
     Item C7. The tubular convective device of Item C5, wherein the air-guide element is disposed within the tube structure. 
     Item C8. The tubular convective device of Item C5, wherein the air-guide element is configured to facilitate forming creases at the edge of the air-guide element when the tubular convective device is inflated and bent. 
     Item C9. The tubular convective device of any one of Item C1-C8, wherein the tubular convective device is in a roll. 
     Item C10. A tubular convective system comprising:
         the tubular convective device of Item C1,   a dispenser containing the tubular convective device.       

     Item C11. The tubular convective system of Item C10, wherein a dispenser comprises a cutting device. 
     Item C12. A tubular convective system, comprising:
         a plurality of tubular convective devices, each tubular convective device comprising:   a tubular structure comprising a flexible material, and   a plurality of apertures on the tubular structure,   wherein adjacent two of the plurality of tubular convective devices are connected.       

     Item C13. The tubular convective system of Item C12, further comprises: a line of weakness between two adjacent tubular convective devices of the plurality tubular convective devices. 
     Item C14. The tubular convective system of Item C12 or C13, further comprises: an close seal between two adjacent tubular convective devices of the plurality tubular convective devices. 
     Item C15. The tubular convective system of Item C13, further comprises: an close seal between two adjacent tubular convective devices of the plurality tubular convective devices, wherein the close seal is disposed proximate to the line of weakness. 
     Item C16. The tubular convective system of any one of Item C12-C15, wherein two of the plurality of tubular convective devices have different length from each other. 
     Item C17. The tubular convective system of any one of Item C12-C16, wherein the plurality of tubular convective devices are in a roll. 
     Item C18. The tubular convective system of any one of Item C12-C17, wherein the tubular structure comprises a blown film. 
     Item C19. The tubular convective system of any one of Item C12-C18, wherein the tubular structure comprises a layer of flexible materials sealed at a longitudinal edge. 
     Item C20. The tubular convective system of any one of Item C12-C19, wherein the tubular structure comprises a first flexible layer and a second flexible layer, wherein the first flexible layer and the second flexible layer are sealed at two longitudinal edges. 
     Item C21. The tubular convective system of Item C20, wherein the plurality of apertures are disposed only on the first flexible layer. 
     Item C22. The tubular convective system of any one of Item C12-C21, wherein the tubular structure comprises a first portion and a second portion separated from the first portion longitudinally, and wherein the plurality of apertures are disposed only on the first portion. 
     Item C23. The tubular convective system of any one of Item C12-C22, wherein each tubular convective device comprises an attachment device. 
     Item C24. The tubular convective system of Item C23, wherein the attachment device comprises an adhesive strip. 
     Item C25. The tubular convective system of Item C23, wherein the attachment device comprises a plurality of adhesive segments disposed in a pattern. 
     Item C26. The tubular convective system of Item C25, wherein the plurality of adhesive segments are disposed in a generally equal spacing longitudinally. 
     Item C27. The tubular convective system of Item C23, wherein the attachment device of a tubular convective device is connected to the attachment device of an adjacent tubular convective device. 
     Item C28. A tubular convective system, comprising:
         a tubular convective device comprising:
           a tubular structure comprising a flexible material, and   a plurality of apertures on the tubular structure; and   
           a fixation element configured to secure a first part of the tubular convective device.       

     Item C29. The tubular convective system of Item C28, wherein the fixation element comprises a ring. 
     Item C30. The tubular convective system of Item C28 or C29, wherein the fixation element comprises a flat element and a flexible element attached to the flat element. 
     Item C31. The tubular convective system of any one of Item C28-C30, further comprises:
         a hose manifold comprising: a hose connector configured to connect to a hose, two outlet connectors configured to connect to two ends of the tubular convective device respectively, wherein the hose connector and the two output connectors are in fluid connection.       

     Item C32. A tubular convective system, comprises:
         a tubular convective device comprising: a tubular structure comprising a flexible material, the tubular structure having two ends, and a plurality of apertures on the tubular structure; and   a hose manifold comprising: a hose connector configured to connect to a hose, two outlet connectors configured to connect to the two ends of the tubular structure respectively, wherein the hose connector and the two output connectors are in fluid connection.       

     The present invention should not be considered limited to the particular examples and embodiments described above, as such embodiments are described in detail to facilitate explanation of various aspects of the invention. Rather the present invention should be understood to cover all aspects of the invention, including various modifications, equivalent processes, and alternative devices falling within the spirit and scope of the invention as defined by the appended claims and their equivalents.