Abstract:
A system for measuring a thermal property of a garment includes a mannequin having a form similar to at least a portion of a mammalian body and adapted to wear the garment. Fluid is circulatable through at least a portion of the mannequin. An outer surface temperature sensor is affixed to the mannequin, and a fluid pressure regulator and temperature controller are located exterior of the mannequin. A meter monitors the energy usage of the controller, which is indicative of the thermal property of the garment. Environmental conditions are controllable, including variable wind speeds and induced mannequin motion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from provisional application 60/225,606, “Inflatable Mannequin, System, and Associated Methods,” filed Aug. 15, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to devices, systems, and methods for measuring thermal properties of clothing, and, more particularly, to such devices, systems, and methods for simulating a shape, size, and temperature of a human body. 
     2. Description of Related Art 
     Exposing a human being or other mammal to an extreme temperature environment, such as high heat levels, places it at risk for disorders and/or illnesses if the exposure exceeds their tolerance. The American Conference of Governmental Industrial Hygienists (ACGIH) has proposed a threshold limit value (TLV) for heat stress and strain, including safe tolerance limits for work in hot environments, which varies according to work intensity and thermal insulation of clothing. Clothing insulation is also an important factor in protection against cold. In addition, other thermal properties of clothing such as vapor permeability and ventilation also affect human heat tolerance. 
     At present there are two direct methods available for the measurement of the thermal properties of clothing such as insulation and ventilation. One method requires the use of an electronically instrumented mannequin, made of metal or plastic, that is placed inside a climatically controlled chamber, the cost of which is known at present to be approximately $1 million. 
     A second method requires human subjects to be exposed to high heat stress conditions inside a climatic chamberwhile exercising and carrying physiological monitoring equipment, including a rectal thermometer. This approach exposes test subjects to heat stress, discomfort, and health risks. Furthermore, because of individual variability, at least 12 test subjects are needed to provide sufficient statistics for such heat stress tests. 
     Ventilation of garments and breathability of the garment&#39;s material are key factors that allow metabolic heat to dissipate from a body. When garment ventilation is high, the insulation values of the protective clothing are of less significance. When the garment ventilation is low, however, the insulation value becomes very important. 
     Few countries around the world are believed to have laboratories where the testing of the thermal properties of protective garments can be performed using such sophisticated and expensive mannequins and instruments (Holmer and Ingar;  Thermal Manikins in Research and Standards ; Proceeding of the Third International Meeting of Thermal Manikin Testing, Oct. 12-13, 1999, the contents of which are incorporated herein by reference). 
     Among references known in the art, Green (U.S. Pat. No. 2,693,088) teaches an apparatus for conditioning compressed air to a flight suit, which regulates the circulating air to a desired temperature. The suit of Palma (U.S. Pat. No. 3,507,321) also provides temperature-regulated heating and/or cooling to all or part of a body. The space suit of Starr (U.S. Pat. No. 3,648,765) has a system for mixing warm and cold liquid to achieve temperature regulation. Chambers et al. (U.S. Pat. No. 3,736,764) disclose a fluid-cooled garment. The temperature of the coolant is based upon an evaporative water loss rate of the wearer. The hospital garment of Hardy (U.S. Pat. No. 3,738,367) has small-diameter tubes for conveying temperature-regulated fluid adjacent the body. Laxo (U.S. Pat. No. 3,743,012) teaches the use of counter-flow heat exchange to maintain an equal temperature distribution along the inner surface of a garment for use by, for example, a diver. The garment of Chuan-Chih (U.S. Pat. No. 4,747,408) provides the wearer with a portable sauna by alternately delivering hot air and cooled water to the garment. Inoshiri et al. (U.S. Pat. No. 5,805,718), in the process of determining an amount of clothing being worn by a subject, calculate the heat discharged out of the clothing and the thermal resistance of the clothing. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a device, system, and method for measuring the thermal properties of clothing. 
     It is an additional object to provide such an invention that is significantly less costly than previous devices and systems. 
     It is a further object to provide such an invention that simulates a plurality of properties of a mammalian body. 
     It is another object to provide a system and method for measuring clothing insulation. 
     It is yet an additional object to provide such a system and method for measuring vapor permeability of a garment. 
     It is yet a further object to provide such a system and method for measuring the ventilation of the garment and the breathability of a garment&#39;s material. 
     It is yet another object to provide a device, system, and method for improving the safety of mammals exposed to high temperatures. 
     A specific object is to provide such an invention for improving worker safety in high-temperature environments. 
     These objects and others are attained by the present invention, one aspect of which comprises a device for measuring a thermal property of a garment. The device comprises a mannequin having a form similar to at least a portion of a mammalian body. The mannequin is adapted to wear a garment for which it is desired to have a thermal property measured. 
     The device further comprises fluid circulating means for receiving a fluid therethrough having an inlet and an outlet. The fluid circulating means is positioned to travel through at least a portion of the mannequin. Means for sensing a temperature and for maintaining a desired temperature of the fluid are located at at least one location exterior of the mannequin. The desired temperature is preferably similar to that of the skin of the mammalian body being simulated. 
     Throughout the present application, the word fluid is not intended as a limitation, and is used to signify any medium that satisfies a requirement for heat transfer as well as allowing the system to maintain constant pressure, including fluids such as water, gases such as nitrogen, mixtures of gases such as air, or combinations or suspensions such as fine particulates in air. 
     The system for measuring a thermal property of a garment comprises a mannequin as above. Means are provided for circulating a fluid through at least a portion of the mannequin, for controlling a temperature of the fluid being circulated for simulating a skin temperature of the mammalian body, for sensing a temperature at at least one location exterior of the mannequin beneath the garment, and for monitoring an energy usage required to control the fluid temperature. The energy usage is indicative of the thermal property of the garment. 
     A method for measuring a thermal property of a garment comprises the steps of placing a mannequin as above in a desired environment and channeling a fluid through at least a portion of the mannequin and establishing a control value. Next a garment for which it is desired to have a thermal property measured is placed onto the mannequin, and a change in the electrical energy is determined. 
     The features that characterize the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description used in conjunction with the accompanying drawing. It is to be expressly understood that the drawing is for the purpose of illustration and description and is not intended as a definition of the limits of the invention. These and other objects attained, and advantages offered, by the present invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates the garment thermal property measurement system of the present invention. 
     FIG. 2 illustrates the suspension system for the mannequin. 
     FIG. 3 illustrates the system for measuring air-flow effect on clothing ventilation. 
     FIG. 4 illustrates an alternate embodiment of a garment thermal property measurement system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description of the preferred embodiments of the present invention will now be presented with reference to FIGS. 1-4. 
     An exemplary system  10  of the present invention (FIG. 1) comprises a device, which in a preferred embodiment comprises a light-weight, flexible, inflatable, and fluid-tight mannequin  20  adapted to resemble a medium-sized adult male or female human body without a head. In a most preferred embodiment, the mannequin  20  further has no hands or feet (or, in the case of another mammal, equivalent coverings for analogous body parts such as paws or tail). This embodiment is not intended as a limitation, however, as it may be conceived by one of skill in the art that other body forms may be included within the scope of the invention, such as a child or an animal, or a body with head, hands, feet, or any combination thereof. 
     The mannequin  20  is substantially hollow in a preferred embodiment, although this is not intended as a limitation, and a unit having solid portions may also be contemplated. The mannequin  20  has a pair of arms  21 , a pair of legs  22 , and an opening  23  at the neck  24 . Testing includes placing the mannequin  20  within a desired environment, first unclad and then clad with a garment  90  desired to be tested for at least one thermal property. Such a garment  90  may include, for example, clothing designed for use in ranges of environments, such as temperatures, ranges of wind speeds, ranges of humidity, ranges of pressures, ranges of irradiance, and any other combination of environmental conditions. The garment  90  may also be contemplated for use in normal ranges of environmental conditions, but wherein the simulated body is undergoing a stressor on its internal conditions, such as exercise or a fever. Likewise a person of skill in the art will recognize that combinations of these conditions may be simulated, and the invention is not intended to be limited to any particular condition or testing regime. 
     The mannequin  20  may comprise any suitable material known in the art durable in the range of temperatures desired to be tested. Some factors, individually or in various combinations, that can be considered in selecting suitable materials are flexibility, tolerance of environmental testing conditions, light weight, heat resistance, and ability to maintain a seal. A person of skill in the art will recognize that materials such as plastics and rubber can be used. In a particular embodiment, the mannequin  20  may comprise a disposable material such as some type of plastic or a combination of material, although this is not intended as a limitation. 
     The fluid circulation means in this embodiment comprises an insulated introducing tube  25  that enters through the neck opening  23 , which is otherwise hermetically sealed, and has a plurality of openings  26  along a portion inside the mannequin  20  for introducing fluid, here air, therewithin. A plurality of return tubes  27 , here four, extend inside the mannequin  20 , one along each limb  21 , 22 . Each return tube  27  has an opening at a distal end  28 , so that air entering through the introducing tube  25  circulates through the mannequin&#39;s interior and exits by entering the return tubes&#39; distal ends  28 . Preferably the arms  21 , legs  22 , and neck  24  have attached thereto detachable airtight closures  50 , 51 , 52 , respectively, at their distal ends  211 , 221 , 241 , to facilitate installation and maintenance of the tubing system (FIG.  2 ). 
     Each return tube&#39;s proximal end  29  joins a manifold  30  outside the mannequin  20 , an insulated exterior return tube  31  leading from which enters a temperature and pressure control unit  32 , from which in turn exits air to join the introducing tube  25 . The control unit  32  comprises a substantially hollow enclosure having an inlet  33  for joining with the exterior return tube&#39;s proximal end  34  and an outlet  35  for joining with the introducing tube&#39;s proximal end  36 . The temperature and pressure control unit  32  in system  10  is preferably housed in a thermally insulated enclosure 
     Inside the control unit  32  is housed a fan  37 . Between the inlet  33  and the fan  37  is an opening  38  in fluid communication with a fluid pressure regulator, here, an air pressure regulator  39 , which is adapted to maintain the pressure within the mannequin  20  and control unit  32  at a desired substantially constant value. Preferably the pressure should be maintained sufficiently high to preserve a desired shape of the mannequin  20  after addition of the garment  90 . 
     Between the fan  37  and the outlet  35  is positioned a heating coil  40 , which is in electrical communication with a watt meter  41  and is under control of a thermostat controller  42 . The thermostat controller  42  is responsive to a signal from a surface temperature sensor integrator  43 , which in turn receives input from a plurality of sensors  44  affixed exterior of, here, against the outside of, the mannequin  20 . In a preferred embodiment there are 15 sensors  44  positioned at 15 locations, in accordance with the ASTM standard, or other locations necessary to determine the mean surface temperature, although these numbers are not intended as limitations. 
     The fluid/air temperature of the system  10  is regulated by an interplay between the sensing and control components: The sensors  44  determine a temperature of the mannequin&#39;s surface, which is relayed to the integrator  43 , which in turn determines a mean surface temperature. This then signals the thermostat controller  42  to regulate the heating level of the heating coil  40  to thereby control the temperature of the air exiting the control unit  32 . 
     The watt meter  41  is adapted to measure the electrical energy consumed by the heating coil  40 , which reflects the magnitude of the garment&#39;s insulation when compared against control values of a mannequin  20  without a garment  90 . 
     An exemplary support system for retaining the mannequin&#39;s shape in a desired orientation (FIG. 2) comprises a frame  53  adapted for placement within the mannequin  20  at the shoulders  54 . The frame  53 , not unlike a clothing hanger in this embodiment, has a hook  55  attached thereto extending out of the neck opening  23  to permit hanging the mannequin  20  therefrom. Other types of framing may also be contemplated, whether in addition to or instead of the foregoing. 
     The support system further comprises a semirigid waistband  56  affixed generally around the mannequin&#39;s waist, which permits the donning of belts and/or waistbands for pants and skirts without substantially altering the shape of the mannequin  20 . Other types of support may also be contemplated, whether in addition to or instead of the foregoing. 
     In a first embodiment of a method of using the system  10  the mannequin  20  is placed into a room or enclosure wherein the air temperature, air movement, and humidity are maintained at a substantially constant level. It is to be understood by one of skill in the art that the room or enclosure utilized in the present invention does not need to comprise a climate control chamber such as is known in the art, permitting a substantially reduced cost of operation for the present invention. The heating system is activated when the mannequin  20  is unclothed, and the average surface temperature of the mannequin  20  is adjusted to simulate that of human (or other homeothermic mammal) skin and is maintained at this level automatically throughout the measurement period, while collecting watt meter  41  data. 
     The garment  90  to be tested is then put on the mannequin  20  and the watt readings recorded with the watt meter  41 . The differences between the unclothed and clothed conditions provide quantitative information on the garment&#39;s insulation properties. The breathability of the garment&#39;s fabric can also be determined separately by first closing the ventilation openings of the garment, such as at the arms, the legs, and the neck. 
     Tests may be conducted under a plurality of conditions, such as under varying wind speed (FIG. 3) to determine ventilation characteristics. Arm  21  and leg  22  motion can be added to measure the effects of walking on garment insulation and ventilation. In addition, the mannequin&#39;s surface could be wetted to determine the effects of garment vapor permeability and insulation on sweat evaporation or under precipitation conditions. 
     The method of using the system  10  of the present invention (FIG. 3) to simulate walking includes attaching a bracket  57  to the distal ends of each arm  21  and leg  22 . The bracket  57  is adapted to have affixed thereto a push-pull rod  58  or wire for moving the arms  21  and legs  22  backwards and forwards to simulate a walking motion with the use of an effector. The method to simulate wind may comprise introducing air flow using an air fan  59  under speed control by controller  60 , which permits measurement of the ventilation properties of the garment  90  at different air velocities. 
     An alternate embodiment (FIG. 4) of the system  10 ′ comprises an alternate mannequin  20 ′, here having a complete set of extremities, including head  61 , hands  62 , and feet  63 . It will be understood that the mannequin also may contain only some of these parts. The control, sensing, and fluid circulation systems are contemplated as remaining substantially the same as those of FIG. 1, although this is not intended as a limitation. A plurality of subsystems can also be utilized. For example, different parts of the mannequin, such as the hands or other extremities, can be connected to separate circulation or control systems. The opening  23 ′ for passing tubes  25  and  27  therethrough is illustrated here as in the shoulder region, although this is not intended as a limitation, and one of skill in the art will appreciate that such an opening  23 ′ may be placed in any convenient location. 
     This system  10 ′ is amenable for testing an all-encompassing garment, such as a body suit, jump suit, uniform, or a space suit, a plurality of garments, such as a hat  91 , gloves  92 , socks  93 , or footwear  94 , or an unfinished garment or fabric, in similar fashion to the embodiment of FIG.  1 . Here the distal ends  28 ′ of the return tubes  27 ′ are preferably located adjacent distal ends of the extremities. Airtight closures  50 ′, 51 ′, 52 ′ may also be provided, here shown being used to affix the hands  62 , feet  63 , and head  61 , to the body, although other affixing methods may be contemplated. 
     It may be appreciated by one skilled in the art that additional embodiments may be contemplated, including various shapes of mannequins for simulating different animals, mannequins having only a part of a body, such as a torso only, head only, limb only, or any combination thereof, and the use of different circulating fluids and fluid circulation and control systems. One of skill in the art will also appreciate that different control systems, such as for pumping and heating, are required for different chosen circulating media. 
     In the foregoing description, certain terms have been used for brevity, clarity, and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for description purposes herein and are intended to be broadly construed. Moreover, the embodiments of the apparatus illustrated and described herein are by way of example, and the scope of the invention is not limited to the exact details of construction.