Abstract:
A thermal manikin has a closed perforated rigid frame covered by a breathable fabric extending over the frame and forming arms and legs. Water passages and a pump inside the manikin direct water around the manikin to simulate natural blood flow. The manikin is provided with a controller and sensor for measuring conditions inside and outside the manikin that enables simultaneous determination of Clo (thermal resistance of clothing placed on the manikin) and Im (the permeability index of the clothing).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to thermal manikins. 
     2. Description of Prior Art 
     Thermal comfort of clothing systems can be evaluated subjectively by wearer trials but such trials can expose the wearer to danger in extreme conditions testing. Objective testing can also be carried out using flat plates and cylindrical methods to evaluate thermal properties of simple clothing, but practically applying results of such test in evaluating thermal comfort of clothing is not normally very useful. Thermal manikins have therefore been developed for providing more useful results. 
     Thermal comfort of clothing is mainly determined by the heat and moisture transferring through the clothing system. In order to optimize the clothing system so as to achieve maximum thermal comfort, considerable research has been carried out on the heat and moisture transfer through clothing systems over many years. The best simulation of a human body wearing clothing is achieved by testing clothing systems on thermal manikins. Presently thermal manikins can comprise these types. The first type are standing and non-perspiring. The second type are movable but non-perspiring. 
     The first or second types have been made perspiring by wetting such that the perspiration is supplied, in effect, from outside to the ‘skin’ using sprinklers or pipes. 
     Such methods of simulating perspiring tend to be poor in reproducibly Although manikins are useful tools for evaluating thermal comfort of overall clothing systems. 
     The third type of manikins are standing and perspiring. They are not widely used because of their relatively high cost. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to overcome or at least to reduce this problem. 
     According to one aspect of the invention there is provided a thermal manikin having a rigid perforated main frame, a closed breathable fabric skin extending over the frame and forming arms and legs of the manikin, a heater mounted inside the frame, water passages inside the manikin to direct water towards extremities of the arm and legs, and a pump to circulate water around the manikin to simulate a natural blood flow of a human body. 
     The heater is preferably mounted in a chest of the manikin. 
     The arms and legs may be arranged so that they can be swung backwards and forwards to simulate walking. 
     An externally mounted topping-up gauge may be provided to enable measurable quantities of water to be added to the inside of the manikin to provide accurate determinations of how much water has used during a testing period. 
     According to another aspect of the invention there is provided a method of measuring thermal comfort of clothes which comprises clothing a thermal manikin, in which the manikin has a rigid perforated main frame, a closed breathable fabric skin extending over the frame and forming arms and legs of the manikin, a heater mounted inside the frame, water passages inside the manikin to direct water towards extremities of the arms and legs, and a pump to circulate water around the manikin to simulate a natural blood flow of a human body, and simultaneously determining Clo (thermal resistance of the clothing) and Im (the permeability index of the clothing). 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A thermal manikin according to the invention will now be described by way of example with reference to the accompanying drawings in which: 
     FIG. 1 is a front schematic view of the manikin; 
     FIG. 2 is front external view of the manikin; and 
     FIG. 3 is a schematic diagram of a control and measurement system for the manikin. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, in FIG. 1 the manikin  10  is made in size and configuration to replicate a typical man. The manikin is 1.7 meters in height and has an outer surface area of approximately 1.5 meters. The outer surface, or skin, has a soft feel and the body is flexible. The manikin has a perforated rigid plastic main frame  11  forming a trunk and head. The main frame  11  is covered by a breathable sealed skin  12 , that also forms arms  13  and legs  14 , which in use is filled with water. The manikin is shown in FIG. 2 with a piece of skin ‘torn away’ to show part of the main frame  11 . The skin  12  is made of three layers, an outer layer of nylon, an inner layer of knitted fabric and a central layer of microporous polytetrafluoroethylene. Suitable materials are already known and used for specialist sports clothing, such materials are available and sold as GORETEX (trade mark) material. 
     A water heater  15  is inside the frame  11 , approximately where a human heart would be situated, and is connected to a supply pipe  16 . The pipe  16  provides a hanging support for the manikin. Water passages inside the manikin are provided by a network of pipes  17  that lead from the heater  15  to extremities of the arms and legs. A pump  18  is used to pump water along the pipes  17  to provide a flow of water (see arrows in FIG. 1) around the inside of the manikin to simulate a natural blood flow of a human body. A topping-up gauge  19  is connected by a manually operable valve  20  to allow the manikin to be re-filled to a top up line with measured quantities of water, as required from time to time. This enables the amount of water used to readily determined after each testing period. 
     When the manikin is supported by the pipe  16 , as described above, the arms and legs are generally free to swing backwards and forwards. Swivellable joints  21  and  22  allow suitable relative movement between the pipes  17 . Thus for simulating walking suitable mechanical ‘pushers’ (not shown) are positioned to pull and push the arms and legs, as required. 
     In use, the manikin&#39;s core temperature is controlled to be 37° C. Normally the manikin is suspended inside a box frame, that may have outer walls to form a cabinet surrounding the manikin. The manikin can produce gaseons ‘perspiration’ to simulate human sweating which will vary according to the amount and type of clothing that is worn. 
     In FIG. 3, the manikin  10  is provided with a number of sensors (known per se) for supplying a computer  23  with information for determining operating conditions during testing. The computer is programmed to control a power supply to the heater  15 , while responding to a temperature sensor  24  inside the manikin, to maintain water temperature inside the manikin at 37° C.; typically the normal body temperature of a human body. In use, the manikin produces heavy gaseous ‘perspiration’. The insensible perspiration of a human body is around 30 g/h, and when sweating can reach 1000 g/h. The perspiration of the manikin varies with the amount and type of clothing worn and can operate over a range of normal human perspiration. It is possible, by providing additional separately controllable pumps or adjustable-valves (not shown) for the pipes  17 , to vary the skin temperature distribution at the surface of the skin  12  where required. As the manikin is supported by the pipe  16  and hangs below the pipe, clothing can be easily put on and taken off the manikin. As already mentioned, the limbs of the manikin can by arranged to be mechanically moved to simulate walking. 
     The computer is programmed to simultaneously determine Clo (thermal resistance) and Im (permeability index):        Clo   =         K   ·   Δ                   T       W                 t                              
     Where k is a constant of proportionality, ΔT is the temperature difference between the skin and surrounding environment, and W t  is the dry heat loss. W T  is the dry heat loss calculated from the total heat loss minus the heat loss due to perspiration. 
     The Im value is determined by the following equation:        W   =       K   Clo          (       Δ                 T     +         I   m     ·   S   ·   Δ                   P       )                              
     Where C is a constant and equals 22° C./mmHg, ΔP is the vapour pressure difference between the skin at its temperature and the environment, and W is the total heat loss. 
     The quantity of water that evaporates during each testing cycles, as explained above, is determined by ‘topping up’ the water inside the manikin using the topping up gauge  19  after each testing cycle. 
     The Table below shows typical test results for the described manikin: 
     
       
         
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Clothing 
                 Ts 
                 Te 
                 Hs 
                 He 
                 W 
                 Q 
                 Clo 
                 Clo DV 
                 Im 
                 Im DV 
               
               
                   
               
             
             
               
                 Nude 
                 35.3 
                 28.6 
                 86.0 
                 67.3 
                 360.5 
                 410 
                 0.64 
                 0.03 
                 0.43 
                 0.02 
               
               
                   
                 35.3 
                 28.6 
                 85.8 
                 66.4 
                 351.0 
                 400 
                 0.66 
                   
                 0.43 
               
               
                   
                 35.3 
                 28.7 
                 85.5 
                 66.5 
                 345.0 
                 395 
                 0.66 
                   
                 0.44 
               
               
                   
                 35.2 
                 28.8 
                 86.4 
                 66.8 
                 344.8 
                 405 
                 0.71 
                   
                 0.47 
               
               
                   
                 35.1 
                 28.5 
                 86.7 
                 67.0 
                 344.4 
                 400 
                 0.70 
                   
                 0.46 
               
               
                 Underwear 
                 35.8 
                 28.1 
                 82.7 
                 63.1 
                 298.2 
                 340 
                 0.88 
                 0.05 
                 0.47 
                 0.04 
               
               
                   
                 35.9 
                 28.1 
                 83.1 
                 63.2 
                 296.0 
                 320 
                 0.78 
                   
                 0.39 
               
               
                   
                 36.0 
                 28.1 
                 83.0 
                 64.2 
                 293.1 
                 310 
                 0.76 
                   
                 0.37 
               
               
                   
                 36.0 
                 27.8 
                 82.6 
                 59.6 
                 294.0 
                 320 
                 0.84 
                   
                 0.39 
               
               
                   
                 35.8 
                 27.5 
                 82.6 
                 60.3 
                 296.3 
                 315 
                 0.81 
                   
                 0.37 
               
               
                 Underwear + 
                 36.4 
                 28.3 
                 87.3 
                 57.8 
                 279.2 
                 310 
                 0.91 
                 0.03 
                 0.36 
                 0.02 
               
               
                 shirt 
                 36.3 
                 27.8 
                 87.1 
                 57.1 
                 278.2 
                 300 
                 0.89 
                   
                 0.34 
               
               
                   
                 36.3 
                 27.8 
                 87.0 
                 57.5 
                 278.9 
                 300 
                 0.89 
                   
                 0.34 
               
               
                   
                 36.2 
                 27.8 
                 87.3 
                 57.2 
                 281.4 
                 295 
                 0.83 
                   
                 0.31 
               
               
                   
                 36.2 
                 27.5 
                 87.5 
                 57.4 
                 281.5 
                 295 
                 0.86 
                   
                 0.32 
               
               
                 Underwear + 
                 36.7 
                 27.0 
                 92.9 
                 59.4 
                 196.4 
                 195 
                 1.16 
                 0.11 
                 0.25 
                 0.03 
               
               
                 shirt + 
                 36.6 
                 27.0 
                 92.7 
                 61.4 
                 195.3 
                 205 
                 1.27 
                   
                 0.30 
               
               
                 suit 
                 36.5 
                 26.8 
                 92.7 
                 61.5 
                 197.8 
                 200 
                 1.20 
                   
                 0.27 
               
               
                   
                 36.4 
                 26.7 
                 92.4 
                 61.1 
                 204.4 
                 200 
                 1.11 
                   
                 0.25 
               
               
                   
                 36.5 
                 26.7 
                 92.7 
                 60.5 
                 212.2 
                 195 
                 0.98 
                   
                 0.22 
               
               
                   
               
             
          
         
       
     
     Where T e  is the mean “skin” temperature, T e  the mean ambient temperature, Hs the mean “skin” humidity, He the mean ambient humidity, W the total heat loss, Q the total water loss due to perspiration, Clo DV the standard deviation of Clo value, Im DV the standard deviation of Im value.