Abstract:
A safety apparatus protects against human injury and loss of life by suppressing flow of fluid and broken pieces from a ruptured high-pressure conduit and provides pressure relief for escaping fluid. The safety apparatus includes a knitted fabric sleeve that encircles the high-pressure conduit. The sleeve may be secured to a coupling associated with the conduit by an attachment feature. The sleeve generally reduces the fluid velocity of the escaping fluid.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present disclosure relates generally to apparatus and methods for protecting against human injury and loss of life due to catastrophic failures in the form of bursts or pin-hole failures in high-pressure fluid conduits such as hoses and tubes, and more particularly to a safety apparatus and methods for enclosing a length of a high-pressure conduit. 
         [0003]    2. Related Art 
         [0004]    As is well known within the hydraulics industry, injury resulting from hose bursts and pin-hole leaks can occur in a matter of milliseconds. Hydraulic systems may operate at very high pressures and fluid conduits can and have burst under these conditions, which can cause severe injury to nearby equipment and people. Sleeves are sometimes used to suppress the burst or pin-hole failures of the fluid conduits. 
       SUMMARY 
       [0005]    Embodiments of the disclosure may include a safety apparatus for a fluid conduit. The safety apparatus may include a knitted fabric sleeve disposed about the fluid conduit. The sleeve may define an interstitial space between the knitted fabric sleeve and the fluid conduit. The knitted fabric sleeve may be more stretchable in a radial direction than in an axial direction. 
         [0006]    In some embodiments, the knitted fabric sleeve includes ribbing extending longitudinally in the axial direction of the knitted fabric sleeve. The knitted fabric sleeve may be substantially impervious to fluid in the fluid conduit. The knitted fabric sleeve may include liquid crystal polyester fibers. The knitted fabric sleeve may include multiple layers attached together only at opposing ends of the sleeve. The knitted fabric sleeve may include an outer layer and one or more inner layers. The outer layer may have a smaller diameter than the one or more inner layers. The safety apparatus may include an adjustable attachment feature that secures the knitted fabric sleeve to a coupling at an end of the fluid conduit. 
         [0007]    Embodiments of the present disclosure may include a method. The method may include disposing a knitted fabric sleeve over a fluid conduit, the knitted fabric sleeve being more stretchable in a radial direction than in an axial direction. The method also may include establishing an interstitial space between the knitted fabric sleeve and the fluid conduit, and securing ends of the knitted fabric sleeve to ends of the fluid conduit. Securing the ends of the knitted fabric sleeve to ends of the fluid conduit may comprise adjusting one or more adjustment elements attached to the knitted fabric sleeve around couplings attached to ends of the fluid conduit. 
         [0008]    In some embodiments, the knitted fabric sleeve includes ribbing extending longitudinally in the axial direction of the sleeve. The knitted fabric sleeve may be substantially impervious to fluid in the fluid conduit. The knitted fabric sleeve may include liquid crystal polyester fibers. The knitted fabric sleeve may include an outer layer and one or more inner layers. The outer layer may have a smaller diameter than the one or more inner layers. 
         [0009]    Embodiments of the present disclosure may include a hose system. The hose system may include a high pressure hose, a knitted fabric sleeve disposed over the hose and defining an interstitial space between the knitted fabric sleeve and the hose, a coupling attached to each end of the hose, and an attachment feature attached to an end of the knitted fabric sleeve. The knitted fabric sleeve may be more stretchable in a radial direction than in an axial direction. The attachment feature may be adjustable. 
         [0010]    In some embodiments, the knitted fabric sleeve includes ribbing extending longitudinally in the axial direction of the sleeve. The knitted fabric sleeve may be substantially impervious to fluid in the high pressure hose. The knitted fabric sleeve may include liquid crystal polyester fibers. The knitted fabric sleeve may include multiple layers attached together only at opposing ends of the knitted fabric sleeve. The knitted fabric sleeve may include an outer layer and one or more inner layers. The outer layer may have a smaller diameter than the one or more inner layers. 
         [0011]    This summary of the disclosure is given to aid understanding, and one of skill in the art will understand that each of the various aspects and features of the disclosure may advantageously be used separately in some instances, or in combination with other aspects and features of the disclosure in other instances. Accordingly, while the disclosure is presented in terms of embodiments, it should be appreciated that individual aspects of any embodiment can be claimed separately or in combination with aspects and features of that embodiment or any other embodiment. 
         [0012]    This summary is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. The present disclosure is set forth in various levels of detail in this application and no limitation as to the scope of the claimed subject matter is intended by either the inclusion or non-inclusion of elements, components, or the like in this summary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The accompanying drawings, which are incorporated in and form part of the specification in which like numerals designate like parts, illustrate examples of the present disclosure and together with the description, serve to explain the principles of the disclosure. 
           [0014]      FIG. 1  is an isometric view of a fluid conduit system in accordance with some embodiments of the present disclosure. 
           [0015]      FIG. 2  is an isometric view of a safety apparatus in accordance with some embodiments of the present disclosure. 
           [0016]      FIG. 3  is an elevation view of the safety apparatus of  FIG. 2  in accordance with some embodiments of the present disclosure. 
           [0017]      FIG. 4  is an enlarged, fragmentary view of an end of the safety apparatus of  FIG. 2  in accordance with some embodiments of the present disclosure. 
           [0018]      FIG. 5  is an enlarged, fragmentary view of an end of the fluid conduit system of  FIG. 1  in accordance with some embodiments of the present disclosure. 
           [0019]      FIG. 6  is a fragmentary, longitudinal cross-section view of an end of the safety apparatus of  FIG. 2  in accordance with some embodiments of the present disclosure. 
           [0020]      FIG. 7  is a plan view of an attachment element of the safety apparatus of  FIG. 2  in accordance with some embodiments of the present disclosure. 
           [0021]      FIG. 8  is an elevation view of the attachment element of  FIG. 7  in accordance with some embodiments of the present disclosure. 
           [0022]      FIG. 9A  is an enlarged, fragmentary view of a knitted fabric sleeve of the safety apparatus of  FIG. 2  in accordance with some embodiments of the present disclosure. 
           [0023]      FIG. 9B  is an enlarged, fragmentary view of a knit pattern of the knitted fabric sleeve of  FIG. 9A  in accordance with some embodiments of the present disclosure. 
           [0024]      FIG. 10  is a transverse cross-section view of the fluid conduit system of  FIG. 1  in accordance with some embodiments of the present disclosure. 
           [0025]      FIG. 11  is a schematic diagram of the fabric sleeve of  FIG. 9A  coupled to a tensile test apparatus for testing the fabric stretch of the sleeve in accordance with some embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The present disclosure is directed to apparatus and methods that provide protection to nearby equipment and persons after a high-pressure conduit has incurred damage in the form of a burst, pin-hole failure, or other damage. ISO 3457, EN474-1, and similar so called “line of sight” protection standards or guidelines state that for hoses carrying material (a fluid) at a pressure of 725 pounds per square inch (psi) or higher, wherein the hose assembly is located within one meter of an operator, or if the material carried within the hose exceeds 50 degrees Celsius, protection is required. A hose can unpredictably burst or develop a pin-hole at any location along its length, making protection very challenging. It would be beneficial to suppress fluid or shrapnel from a hose burst or pin-hole failure so that nearby equipment and persons are entirely protected from danger. 
         [0027]    An example of a safety apparatus that provides protection of equipment and persons nearby a high pressure fluid conduit can be seen in embodiments of the present disclosure. The safety apparatus may include a sleeve disposed about a fluid conduit. The sleeve may be more stretchable in a radial direction than in an axial direction to decrease the velocity and pressure of fluid escaping from the fluid conduit. The safety apparatus may include an attachment feature that reliably and fixedly secures the safety apparatus to the fluid conduit. The various embodiments of the present disclosure are low-cost, simple to manufacture and implement at time of manufacture or as a retrofit, and are lightweight, elegant, and effective. 
         [0028]    In some embodiments, a method of slidably disposing a sleeve over a fluid conduit may include establishing an interstitial space between the sleeve and the fluid conduit and securing ends of the sleeve to ends of the fluid conduit. The sleeve may be more stretchable in a radial direction than in an axial direction to decrease the velocity and pressure of fluid escaping from the fluid conduit. 
         [0029]    In some embodiments, a hose system decreases the velocity and pressure of fluid escaping from a damaged conduit. The hose system may include a high pressure hose, with a sleeve disposed over the hose. The hose system may define an interstitial space between the sleeve and the hose. The sleeve is preferably more stretchable in a radial direction than in an axial direction to reduce the velocity and pressure of streams of high pressure fluid resulting from a pinhole puncture of the hose, and/or capable of containing or suppressing bursting of the hose, at a pressure above a rated pressure of the hose. Typically, a coupling or the like is disposed in each end of the hose, and an attachment feature secures each end of the sleeve to the coupling. 
         [0030]      FIG. 1  shows a fluid conduit system  100  in accordance with some embodiments of the present disclosure. The fluid conduit system  100  may include a high-pressure fluid conduit  102 , couplings  104  attached to opposing ends of the fluid conduit  102 , and a safety apparatus  106  disposed around the fluid conduit  102  and attached to the couplings  104 . In various embodiments, the high pressure conduit  102  may comprise hydraulic fluid conduits, such as hydraulic hose, line, or pipe. In typical hydraulic conduit construction, the couplings  104  include a stem that is insertable into an end of the conduit  102  and an interface feature such as a flange with bolt apertures allows other components to be attached to the conduit  102  to close a hydraulic circuit. To secure the stem in the conduit  102 , a ferrule  108  (see  FIG. 5 ) may be concentrically affixed about the conduit  102 , typically by crimping, rolling, swaging, or other compression methods. The ferrule  108  may comprise carbon steel, stainless steel, Monel, cast iron, titanium, nano materials, aluminum, brass, and other machinable alloys as well as certain plastics such as resin polymer material. 
         [0031]    Referring to  FIG. 1 , the safety apparatus  106  surrounds the fluid conduit  102 . It should be understood the safety apparatus  106  may be used in conjunction with conduits or bundles of conduits of virtually any type or size including conduits in the farming, heavy duty equipment, aerospace, power, medical, oil, automotive, and other industries. In various embodiments, high pressure fluid in the form of a liquid may be carried by the conduit  102 . However, it should be understood that the safety apparatus  106  can be applied to conduits carrying any type of material, including high pressure hydraulic fluids such as synthetic compounds, mineral oil, water, water-based mixtures, or any other material. 
         [0032]    Referring still to  FIG. 1 , the safety apparatus  106  may include a sleeve  110  positioned around the fluid conduit  102 . The sleeve  110  may comprise a full-length, but preferably otherwise slightly oversized, sleeve, which may encircle the entire circumference of the conduit  102 . The sleeve  110  may define an interstitial space between the conduit  102  and the inner surface of sleeve  110 . The sleeve  110  may extend along the entire length of conduit  102 , so that a burst, pin-hole failure, or other form of damage to the conduit  102  is surrounded by the sleeve  110 . 
         [0033]    The sleeve  110  may be affixed to the conduit  102  by an attachment feature  112 . The attachment feature  112  may be tightened snugly and concentrically around the sleeve  110  to attach the sleeve  110  to the conduit  102 . The attachment feature  112  may be disposed near an end of the sleeve  110  and disposed around the ferrule  108  (see  FIG. 5 ) to secure the sleeve  110  to the coupling  104 . It should be understood by one of ordinary skill that the attachment feature  112  may be affixed to the conduit  102 , the coupling  104 , and/or the protective sleeve  110  before or after the sleeve  110  has been placed around the conduit  102 . 
         [0034]    The attachment feature  112  may be disposed around an end of the sleeve  110  and an associated coupling  104  to secure the sleeve to the conduit  102 . The attachment feature  112  may secure the end of the sleeve between the attachment feature  112  and the coupling  104 . The attachment feature  112  may be disposed over a ferrule  108  that secures the coupling  104  to an end of the fluid conduit  102 . The attachment feature  112  may secure the end of the sleeve  110  between the attachment feature  112  and the ferrule  108 . 
         [0035]      FIGS. 2 and 3  show different views of the safety apparatus  106  in accordance with some embodiments of the present disclosure. The safety apparatus  106  generally includes a pair of attachment features  112  attached to opposing ends of the sleeve  110 . The sleeve  110  may be formed as an elongate tube. The length of the sleeve  110  is determined by the length of the fluid conduit  102  to cover. In some embodiments, the length of the sleeve  110  is greater than the length of the fluid conduit  102  to ensure the sleeve  110  surrounds the entire length of the conduit  102 . The diameter of the sleeve  110  is determined by the diameter and pressure rating of the fluid conduit  102 . The sleeve  110  has a larger inner diameter than an outer diameter of the fluid conduit  102  to define an interstitial space between the sleeve  110  and the fluid conduit  102 . The sleeve  110  may be oversized relative to the fluid conduit  102  to ease installation of the sleeve  110  over the fluid conduit  102 . 
         [0036]      FIG. 4  shows an enlarged, fragmentary view of an end of the safety apparatus  106  in accordance with some embodiments of the present disclosure. The sleeve  110  may include multiple layers attached to one another at their ends (see  FIG. 6 ). In some embodiments, the layers of the sleeve  110  are attached to one another by a circumferentially-extending line of stitching  114 . The layers of the sleeve  110  extending along the length of the sleeve  110  are not attached to one another between the lines of stitching  114  to allow the layers to independently expand in a radial direction during conduit failure and reduce the velocity and pressure of the fluid escaping from the conduit  102 . 
         [0037]    Referring to  FIGS. 4-6 , the attachment feature  112  may be attached to a respective end of the sleeve  110 . The attachment feature  112  may include multiple attachment elements, such as straps or webbing, for securing the sleeve  110  to the coupling  104 . The attachment elements may include two adjustable straps  116 ,  118  spaced longitudinally apart from one another along a length dimension of the sleeve  110 . The adjustable straps  116 ,  118  may be formed in a loop and may be adjustable to increase or decrease the inner dimension of the straps  116 ,  118  to loosen or tighten the straps  116 ,  118  around the sleeve  110 . The first adjustable strap  116  may extend around the circumference of the sleeve  110  and may be tightened around the sleeve  110  to secure the sleeve  110  around an end of the fluid conduit  102 . The second adjustable strap  118  may extend around the circumference of the coupling  104  and may be tightened around the coupling  104  to secure the sleeve  110  to the coupling  104 . The straps  116 ,  118  may be identical or substantially identical to one another. Each strap  116 ,  118  may include a connector  119  for retaining the ends of the straps  116 ,  118  and forming the straps  116 ,  118  in an adjustable loop. 
         [0038]    The straps  116 ,  118  may be attached to one another to prevent movement of the sleeve  110  relative to the coupling  104 . In some embodiments, the adjustment feature  112  includes multiple longitudinally-extending connector straps  120 ,  122 ,  124  spaced equally around the sleeve  110 . The connector straps  120 ,  122 ,  124  may be attached at one end to the first adjustable strap  116  and at an opposing end to the second adjustable strap  118 . The length of the connector straps  120 ,  122 ,  124  may set the maximum longitudinal distance between the first and second adjustable straps  116 ,  118 . The connector straps  120 ,  122 ,  124  may be fixedly attached to the end of the sleeve  110  by stitching  126 , for example. It should be understood by one of ordinary skill that although three connector straps  120 ,  122 ,  124  are described, the attachment feature  112  may include more or less than three connector straps  120 ,  122 ,  124 . 
         [0039]    Referring to  FIG. 6 , each connector strap  120 ,  122 ,  124  may include closed loops  128 ,  130  formed at opposing ends of the straps  120 ,  122 ,  124 . A first closed loop  128  may be formed at a first end of the connector straps  120 ,  122 ,  124  and may define receiving spaces for receiving the first adjustable strap  116 . The first adjustable strap  116  may be routed through the receiving spaces of the first closed loops  128  of the connector straps  120 ,  122 ,  124  and may be tightened around the sleeve  110  to secure the sleeve  110  to the coupling  104 . A second closed loop  130  may be formed at a second end of the connector straps  120 ,  122 ,  124  and may define receiving spaces for receiving the second adjustable strap  118 . The second adjustable strap  118  may be routed through the receiving spaces of the second closed loops  130  of the connector straps  120 ,  122 ,  124  and may be tightened around the coupling  104  to secure the sleeve  110  at a second location along the coupling  104 . As shown in  FIG. 5 , the second adjustable strap  118  may be securely tightened around a reduced outer diameter portion  132  of the coupling  104  to ensure the sleeve  110  does not move longitudinally along the conduit  102  and uncover an end of the conduit  102  during failure of the conduit  102 . 
         [0040]      FIGS. 7 and 8  show different views of an attachment element  134  in accordance with some embodiments of the present disclosure. The attachment element  134  may include an adjustment strap, such as adjustment straps  116  or  118 , and a connector  119  attached to a first end of the adjustment strap  116 ,  118 . The adjustment strap  116 ,  118  may be formed into a loop around the sleeve  110  and a second end of the adjustment strap  116 ,  118  may be adjustably attached to the connector  119  by routing the second end around a transverse rail of the connector  119 . The strap  116 ,  118  may then be tightened around the sleeve  110  and ferrule  108  of the coupling  104  (see  FIG. 5 ). The attachment element  134  may include one or more fastening elements  136  for interfacing with the connector straps  120 ,  122 ,  124 . The fastening elements  136  may be equally distributed along the length of the adjustable straps  116 ,  118  and may secure the connector straps  120 ,  122 ,  124  to the adjustable straps  116 ,  118 . In some embodiments, the fastening elements  136  comprise one of a hook and loop fastener, and the other of the hook and loop fastener is secured to the connector strap  120 ,  122 ,  124  within the closed loops  128 ,  130  (see  FIG. 6 ) to attach the connector straps  120 ,  122 ,  124  to the adjustable straps  116 ,  118  and set the circumferential position of the connector straps  120 ,  122 ,  124  relative to the adjustable straps  116 ,  118 . 
         [0041]    The sleeve  110  may be constructed of one or more layers of knitted fabric.  FIG. 9A  shows a portion of the knitted fabric sleeve  110 . The knitted fabric sleeve  110  includes vertical columns of ribs  137  resulting from alternating knit stitches  138  and purl stitches  140 . Within each horizontal row of the knitted fabric sleeve  110 , a knit stitch  138  alternates with a purl stitch  140 . The knit stitches  138  form ribs  137  on one side of the knitted fabric sleeve  110 , and the purl stitches  140  form ribs on the opposite side of the knitted fabric sleeve  110 . The ribs  137  are oriented longitudinally (running in direction  142 ) along the length of the knitted fabric sleeve  110 , resulting in more stretch in the width or radial direction (direction  144 ) of the sleeve  110 . Referring to  FIG. 9B , an enlarged, fragmentary knit pattern of the knitted fabric sleeve  110  is provided. As shown in  FIG. 9B , the knit stitches  138  and the purl stitches  140  may intermesh alternately on the face and the back of the knitted fabric sleeve  110 . 
         [0042]    Referring to  FIGS. 9A and 9B , the knitted fabric sleeve  110  may include an even ribbing combination. That is, the number of columns of knit stitching  138  is the same as the number of columns of purl stitching  140 .  FIGS. 9A and 9B  show the knitted fabric sleeve  110  with 1×1 ribbing. That is, single knit stitches  138  alternate with single purl stitches  140 , creating narrow ribs  137 . The ribs  137  extend the full length of the knitted fabric sleeve  110 . Other patterns of ribbing  137  may be used. In some embodiments, the knitted fabric sleeve  110  includes 2×2 ribbing having two knit stitches alternating with 2 purl stitches. 
         [0043]    The knitted fabric sleeve  110  may be substantially impervious in that it may slow the velocity of a high velocity and/or high-temperature stream or burst of escaping material from a location of damage along the length of conduit. Preferably, the sleeve  110  is impermeable to a point that it only allows suppressed fluid to seep or weep through the sleeve  110 , with little, or no, discernible energy. The knitted fabric sleeve  110  may be constructed of a substantially impervious material which will stop the stream of fluid produced by a pin-hole puncture or other breach in the conduit  102  at an elevated pressure, such as at twice the rated pressure of the conduit  102 . 
         [0044]    The knitted fabric sleeve  110  may be reinforced with fibers. The fibers may be incorporated in the rib stitches  138  and may extend lengthwise along the full length of the knitted fabric sleeve  110 . In some embodiments, the fibers are comprised of synthetic high-performance fibers, such as poly(p-phenylene-2,6-benzobisoxazole), polyester, polyamide, polyolefins, including ultra-high-molecular-weight polyethylene, or aramid. In some embodiments, the knitted fabric sleeve  110  is reinforced with aromatic polyester and/or liquid crystal polymer, which are offered under the trademark Vectran®. These fibers have thermal stability at high temperatures, high strength and modulus, low creep, and good chemical stability. These fibers also are moisture resistant and generally stable in hostile environments. These fibers may be used in combination with a polyester or polyurethane coating around a Vectran® core to improve abrasion resistance and act as a water barrier. These fibers also have a high resistance to ultraviolet radiation for extended use in the field. 
         [0045]    Referring still to  FIG. 9 , the knitted fabric sleeve  110  may have different stretch properties in different directions. The knitted fabric sleeve  110  may include reinforcing fibers extending lengthwise along a length direction  142  of the sleeve  110  to reduce the stretch capability but increase the strength of the sleeve  110  in a lengthwise direction. The reduced stretch of the sleeve  110  in the length direction  142  may facilitate retention of the sleeve  110  around the couplings  104 . The knitted fabric sleeve  110  may be more stretchable in a radial or width direction  144  than in a length direction  142 . Referring to  FIG. 9 , the radial or width direction  144  of the knitted fabric sleeve  110  may extend perpendicular to the ribs  137  and may be defined by the circular knitting direction or courses. The length direction  142  may extend parallel to the ribs  137  or wales of the knitted fabric sleeve  110 . During failure of the fluid conduit  102 , the sleeve  110  may expand in the radial or width direction  144  to increase the diameter of the sleeve  110  and absorb the energy of the escaping fluid. 
         [0046]    The sleeve  110  may have a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of less than 20%. In some embodiments, the sleeve  110  has a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of less than 10%. In some embodiments, the sleeve  110  has a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of between about 5% and about 10%. In some embodiments, the sleeve  110  has a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of about 8%. 
         [0047]    The sleeve  110  may have a fabric stretch in the radial or width direction  144  per ASTM D2594-99a (with a 5 pound-force load) of greater than 50%. In some embodiments, the sleeve  110  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 50% and about 100%. In some embodiments, the sleeve  110  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 60% and about 90%. In some embodiments, the sleeve  110  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of about 75%. 
         [0048]    The knitted fabric sleeve  110  may include one layer or multiple layers of similar or different materials depending on the performance needs of the sleeve  110 . The size, thickness, strength, and the like of the sleeve  110  can be selected to suit a particular fluid conduit  102  application.  FIG. 10  shows a transverse cross-section view of a fluid conduit system  100  taken along a length of the sleeve  110  between the attachment features  112  in accordance with some embodiments of the present disclosure. The sleeve  110  surrounds the fluid conduit  102  to protect nearby equipment and persons. The sleeve  110  may have a larger inner diameter than an outer diameter of the fluid conduit  102  to define an annular or interstitial space  145  between the sleeve  110  and the fluid conduit  102 . The interstitial space  145  may provide space for fluid to accumulate during failure of the fluid conduit  102 . The interstitial space  145  may grow in volume during failure as the knitted fabric sleeve  110  radially expands during failure of the fluid conduit  102  under the pressure of the escaping fluid. As shown in  FIGS. 6 and 10 , the sleeve  110  may include multiple layers attached together only at opposing ends of the sleeve  110 . In some embodiments, the layers are attached together with lines of stitching  114 , but only at the ends. In some embodiments, the multiple knit layers are not in any way restricted radially by any other non-expansive or less-expansive material, strap, fabric, or stitching, or attached to each other except at the ends as shown and described. 
         [0049]    Referring to  FIG. 10 , the knitted fabric sleeve  110  may include an outer layer  146  and one or more inner layers  148 . In  FIG. 10 , the sleeve  110  includes four inner layers  148   a ,  148   b ,  148   c ,  148   d , collectively referred to as inner layers  148 . It should be understood by one of ordinary skill the number of layers may change depending on the performance requirements of the sleeve  110 , which may be determined by the pressure and volume of fluid in the fluid conduit  102 . In one particular application, the sleeve  110  includes one outer layer  146  and seven inner layers  148  for protecting against injury resulting from failure of a 3.5 inch high-pressure hose. 
         [0050]    The outer layer  146  and the inner layers  148  may have different diameters. In some embodiments, the outer layer  146  has a smaller outer diameter than the one or more inner layers  148 . The smaller outer diameter of the outer layer  146  may slightly restrain the expansion of the inner layers  148  during failure of the fluid conduit  102 . The inner layers  148  may have the same outer diameters. In one particular application for a 3.5 inch high-pressure hose, the outer layer  146  is 7.75 inches tubular or 15.5 inches open width, and the inner layers  148  are 8.375 inches tubular or 16.75 inches open width. 
         [0051]    The outer layer  146  and the inner layers  148  may be constructed of the same or substantially the same knit pattern. In some embodiments, the outer layer  146  and the inner layers  148  include 1×1 ribbing extending lengthwise along the length of the sleeve  110 . In some embodiments, the outer layer  146  has slightly different courses and wales per inch than the inner layers  148 . In some embodiments, the outer layer  146  has fewer courses per inch and fewer wales per inch than the inner layers  148 . In some embodiments, the inner and outer layers are substantially of the same knit construction and dimensions, within normal knitting tolerances. In one particular application for a 3.5 inch high pressure hose, the outer layer  146  may have 19.5 courses per inch (plus or minus 3 courses per inch), and the inner layers  146  may have 19 courses per inch (plus or minus 3 courses per inch). In this particular application, the outer layer  146  may have 15.52 wales per inch (plus or minus 3 wales per inch) and the inner layers may have 16.59 wales per inch (plus or minus 3 wales per inch). It should be understood by one of ordinary skill in the art the number of courses per inch and wales per inch may vary depending on the performance requirements of the sleeve  110 . 
         [0052]    The outer layer  146  and the inner layers  148  may be constructed of the same material. In some embodiments, the outer layer  146  and the inner layers  148  are constructed of yarns reinforced with (or comprising or even consisting of) liquid crystal polymer fibers, such as those sold under the trademark Vectran®. The outer layer  146  and the inner layers  148  may have the same linear mass density. In some embodiments, the outer layer  146  and the inner layers  148  are 800 denier. It should be understood by one of ordinary skill the denier may vary depending on the particular fluid conduit  102  application. The outer layer  146  and the inner layers  148  may include a durable water repellant finish. 
         [0053]    The outer layer  146  and the inner layers  148  may have substantially the same fabric stretch characteristics in the length or longitudinal direction  142 . In some embodiments, the outer layer  146  and the inner layers  148  each have a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of less than 20%. In some embodiments, the outer layer  146  and the inner layers  148  each have a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of less than 10%. In some embodiments, the outer layer  146  and the inner layers  148  each have a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of between about 5% and about 10%. In some embodiments, the outer layer  146  and the inner layers  148  each have a fabric stretch in the length or longitudinal direction  142  per ASTM D2594-99a (with a 5 pound-force load) of about 8%. 
         [0054]    The outer layer  146  and the inner layers  148  may have substantially the same, similar, or different fabric stretch characteristics in the width or radial direction  144 . The outer layer  146  may have a fabric stretch in the radial or width direction  144  per ASTM D2594-99a (with a 5 pound-force load) of greater than 50%. In some embodiments, the outer layer  146  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 50% and about 90%. In some embodiments, the outer layer  146  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 60% and about 80%. In some embodiments, the outer layer  146  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of about 70%. Each inner layer  148  may have a fabric stretch in the radial or width direction  144  per ASTM D2594-99a (with a 5 pound-force load) of greater than 50%. In some embodiments, each inner layer  148  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 70% and about 100%. In some embodiments, each inner layer  148  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of between about 80% and about 90%. In some embodiments, each inner layer  148  has a fabric stretch in the radial direction  144  per ASTM D2594-99a (with a 5 pound-force load) of about 85%. 
         [0055]      FIG. 11  is a schematic diagram of the fabric sleeve of  FIG. 9A  coupled to a tensile test apparatus in accordance with some embodiments of the present disclosure. The tensile test apparatus is schematically represented as a hanger assembly  150  including an upper hanger  152 , a lower hanger  154 , an upper hanger rod  156  attached to the upper hanger  152 , a lower hanger rod  158  attached to the lower hanger  154 , and a support  160  coupled to the upper hanger  152 . The sleeve  110  is represented as being formed in a tube that is disposed around the upper and lower hanger rods  156 ,  158  of the upper and lower hangers  152 ,  154 , respectively. A force F is schematically represented as being applied to the lower hanger  154  to stretch the sleeve  110  between the upper and lower hangers  152 ,  154 . The actual test was conducted using a tensile tester manufactured by Instron. 
         [0056]    To test the fabric stretch of the sleeve  110  in the radial direction  144  (see  FIG. 9A ), a radial test specimen was formed by obtaining an approximately five-inch long section of the tubular sleeve  110 , and positioning the sleeve  110  around the hanger rods  156 ,  158  such that the ribs  137  were oriented parallel to the hanger rods  156 ,  158 . To test the fabric stretch of the sleeve  110  in the longitudinal direction  142  (see  FIG. 9A ), an approximately 15.5 inch piece of the tubular sleeve  110  of  FIG. 9A  was cut lengthwise parallel to the ribs  137 , folded and stitched into a loop such that each rib  137  formed a continuous ring, and the loop was positioned around the hanger rods  156 ,  158  such that radial direction  144  of the sleeve  110  of  FIG. 9A  was oriented parallel to the hanger rods  156 ,  158 . An upper mark  162   a  and a lower mark  162   b  (collectively referred to as the marks  162 ) were formed on an outer surface of the sleeve  110  parallel to the hanger rods  156 ,  158  and were located at a known distance D apart from one another. 
         [0057]    Each test specimen was stretch tested by first cycling the applied force F four times between 0 and 5 lbf, allowing four to six seconds to complete each cycle. Then, a fifth cycle was started, and the applied force F was held at 5 lbf for five to ten seconds. During the holding time period, the distance D between the marks  162  was measured. The fabric stretch was calculated by subtracting the original distance (distance D between the marks  162  measured prior to applying force F) from the tensioned distance (distance D between the marks  162  measured while the tension force F was being applied to the specimen), dividing that net distance by the original distance, and multiplying the resulting number by 100. 
         [0058]    As an Example of an embodiment of the invention, a single outer layer  146  and a single inner layer  148  of the sleeve  110 , 1×1 circular rib knit of Vectran® liquid crystal polymer 800-denier yarn, approximately 19 courses per inch and 16 wales per inch (˜250 wales in circumference), were independently stretch tested in the longitudinal direction  142  and the radial direction  144  (see  FIGS. 9A and 10 ) pursuant to ASTM D2594-99a with a five pound-force load. The outer layer was black-colored Vectran® and the inner layer was natural-colored. The outer layer  146  had a fabric stretch in the longitudinal direction  142  of 8.2% and a fabric stretch in the radial direction  144  of 68.4%. The inner layer  148  had a fabric stretch in the longitudinal direction  142  of 8.4% and a fabric stretch in the radial direction  144  of 84.4%. The fabric stretch of the sleeve  110  may be altered by changing the material, dimensions, weave pattern, or other suitable characteristics of the outer layer  146 , one or more of the inner layers  148 , or any combination thereof to tailor the stretch properties of the sleeve  110  to a particular application. 
         [0059]    An Example safety apparatus having seven inner layers of the above circular knit and one outer layer was constructed according to an embodiment of the invention. The Example included stitching  114  to hold the eight layers together only at opposite ends. Attachment features  112  were fixedly attached only at opposite ends. The knit layers were not otherwise restricted or attached to each other except at the ends as described. The sleeve was applied to a length of 3½-inch, grade-D, steel-cable-reinforced, high-pressure hose. The attachment features were secured to couplings at either end of the hose assembly. The hose, having been scored into the outer cable layer in order to induce a controlled burst, was then pressurized at a rate of about 3 bars/s. Burst occurred at approximately 10,000 psi (˜700±100 bars). The test was repeated on two Example specimens, resulting in only one or two inner layers, respectively, of knit fabric receiving any damage, and the ruptured hose being entirely contained. 
         [0060]    As a first comparative example, the same construction as the Example was made but with additional reinforcing straps  116  attached circumferentially thereto at intermediate locations approximately every foot of hose length, i.e., not only restricted at the respective ends. The first comparative sleeve failed to contain the rupture. 
         [0061]    As a second comparative example, a similar construction as the Example was made but with a tightly square-woven Kevlar® ballistic cloth used as the innermost and outer layers, with six layers of the Vectran® circular knit from the Example there between. The stitching, attachment features, and testing were carried out as in the Example. The second comparative example failed to contain the burst, which ripped through all eight layers of fabric. 
         [0062]    Referring back to  FIGS. 1-5 , to assemble the fluid conduit system  100 , one or more layers of the sleeve  110  may be fixedly attached to one another only along their respective ends. In some embodiments, the one or more layers of the sleeve  110  are stitched together along circumferentially-extending lines of stitching  114 . Attachment features  112  may be fixedly secured to ends of the sleeve  110 . In some embodiments, connector straps  120 ,  122 ,  124  are attached to ends of the sleeve  110 . The connector straps  120 ,  122 ,  124  may be spaced evenly around a periphery of the sleeve  110  and may be fixedly secured to the sleeve  110  by stitching, for example. 
         [0063]    The connector straps  120 ,  122 ,  124  may extend lengthwise along a length of the end of the sleeve  110  and may include a portion extending beyond the end of the sleeve  110 . A first adjustable strap  116  may be routed through loops  128  formed in ends of the connector straps  120 ,  122 ,  124 . A second adjustable strap  118  may be routed through loops  130  formed in opposing ends of the connector straps  120 ,  122 ,  124  that are cantilevered from the end of the sleeve  110 . The sleeve  110  may be disposed over a fluid conduit  102  and may be oversized relative to the fluid conduit  102  so as to define an interstitial space between the sleeve  110  and the fluid conduit  102 . The first adjustable strap  116  may be tightened around a ferrule  108  disposed around an end of the fluid conduit  102 , and the second adjustable strap  118  may be tightened around a coupling  104  attached to the end of the fluid conduit  102 . The first and second adjustable straps  116 ,  118  may secure the ends of the sleeve  110  around the ends of the fluid conduit  102  to ensure fluid or broken conduit pieces escaping from a failure of the fluid conduit  102  is suppressed by the sleeve  110  to prevent damage to nearby equipment or persons. The attachment features  112  are attached only at ends of the sleeve  110  to permit radial expansion of the sleeve  110  during failure of the fluid conduit  102 . The safety and well-being of persons standing nearby and/or operating or maintaining the hydraulic system, commonly known as line of sight protection, is achieved at least in part by providing a secure means of attachment of the sleeve  110  to the conduit  102 . 
         [0064]    In summary, many industries can take advantage of the embodiments of the present safety apparatus and methods for high pressure conduits. The safety apparatus may be applied to any high pressure conduit in a retrofit manner or during production. The resultant protection is effective for conduits carrying even very high pressure fluids. The safety apparatus preferably prevents injury to the operator and/or damage to the associated equipment. The safety apparatus may include a knitted fabric sleeve, which may have two-directional stretch properties. In some embodiments, the knitted fabric sleeve expands or stretches more radially than longitudinally. The knitted fabric sleeve may be formed as a tubular fabric or as an open-width fabric including longitudinally-extending edges that are secured together to form a tubular construction. The knitted fabric sleeve may include one or more layers that are attached together at their ends. Each layer may be slipped into a next consecutive layer and stitched together at their ends. The layers may be portions of a single knit tube slipped into or over itself. Attachment features may be attached to each end of the sleeve to secure the sleeve to the fluid conduit. In some embodiments, the sleeve does not include a ballistic cover for abrasion resistance because the ballistic cover overly restricts the radial expansion or stretching of the knitted fabric sleeve. In some embodiments, the sleeve has features, such as stitching, that may restrict the natural radial stretchiness of the sleeve only at the ends of the sleeve. The sleeve may be used in high-pressure applications with, but not limited to, 3-4″ hose, which may include rubber or plastic and may include reinforcing cables, wires, or yarns. 
         [0065]    The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more aspects, embodiments, or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain aspects, embodiments, or configurations of the disclosure may be combined in alternate aspects, embodiments, or configurations. Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate embodiment of the present disclosure. 
         [0066]    All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for identification purposes to aid the reader&#39;s understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of this disclosure. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority, but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary.