Abstract:
A sample encapsulation system includes a base, a chamber having an inlet and a chamber housing in which the chamber is housed. The chamber is fixedly mounted at least in part within the housing and the housing is movably mounted to the base. The system includes a cap, a first ram operably mounted to the cap for engaging the chamber inlet and a second ram positioned in the chamber opposite the inlet. The second ram is movable toward and away from the first ram. The chamber and housing are movable toward the cap for engaging the first ram with the chamber inlet during an encapsulation cycle and away from the cap, disengaging the first ram from the chamber inlet following an encapsulation cycle. The system includes heating and cooling assemblies and a temperature sensor located remotely from the chamber interior to automatically isolate cooling water to the system.

Description:
RELATED APPLICATIONS 
     The present application is a National Phase of International Application Number PCT/US2013/050703 filed Jul. 16, 2013 and claims priority of U.S. Provisional Application No. 61/672,527 filed Jul. 17, 2012. 
    
    
     BACKGROUND 
     The examination of samples, such as by metallographic examination, requires a number of preparatory steps. For example, a sample may need to be cut or sectioned to a specific size, mounted or encapsulated in a supporting material and ground and/or polished for examination. Such samples are mounted to facilitate handling and to maintain the ability to distinguish between the sample and the material in which the sample is mounted. Mounting materials are typically resins, such as thermoset or thermoplastic resins, including phenolics, phthalates, epoxies, methacrylates and the like. Such materials are commercially available from Buehler, an ITW Company, of Lake Bluff, Ill. 
     Mounting can be carried out in a number of ways. One way in which to mount a sample is a compression mounting process. In a compression mounting process, the sample is placed in a chamber or mold along with the mounting compound. The sample and compound are heated under pressure for example, by use of heating coils and a hydraulic ram. After a predetermined period of time at a set temperature and pressure, the heat source is isolated from the mold, and a cooling fluid is circulated around the mold to cool the encapsulated sample. After a predetermined period of time, the pressure is released and the sample is removed from the mold. 
     If the encapsulated sample (i.e., the sample and the molding compound) is not sufficiently cooled prior to releasing pressure and removal from the mold, the molding compound may change shape or shrink (for example, pull away from the sample). This can result in abrasive rounding the edges of the sample during later sample preparation steps, such as grinding, which may compromise the later metallographic examination. In addition, it may be difficult to handle the encapsulated sample if it is not sufficiently cooled. 
     To prevent premature removal of the sample, in a typical operation, the cooling system is operated for a set period of time. This time is used regardless of whether the sample has already reached a desired final temperature. As such, and as often occurs, the cooling system is run too long and the cooling liquid, usually water from a municipal water system, is wasted. 
     In a compression mold system, the mold that is used, as stated above, is maintained under high pressure at a high temperature. It is not unusual for the mold to reach pressures as high as 4000 psi. within the mold or pressure chamber. In a conventional system, the sample and material are positioned in the mold and a cap is positioned on an upper end of the mold. A hydraulic ram is moved into the chamber to exert a force on the sample and material, and heating coils are actuated to heat the chamber with the material and sample. The chamber is a straight-walled cylindrical chamber and the cap includes a plug that, once the cap is locked in place, inserts into the top of the chamber. The plug fits tightly into the chamber to assure that the pressure boundary within the chamber is maintained. 
     One drawback to this configuration is that the plug that inserts into the top of the chamber can be difficult to insert due to the tight tolerances, and the cap may be difficult to secure or lock onto the chamber. It may also be difficult to loosen and remove the cap as the plug fits tightly in the chamber top. 
     In that such systems operate at high temperatures and pressures, the closure systems, that is the caps that fit onto the mold or pressure chamber are quite heavy, as they are typically fabricated from steel. In addition, the caps are mounted to the system so as to remain attached to the system. As such, the caps can be difficult to maneuver and can require considerable force (or user strength) to manipulate. 
     Accordingly, there is a need for a sample preparation or encapsulation system having a mold chamber that readily permits closing and locking as well as unlocking and opening the chamber cap without undue exertion by an operator. Desirably, such a system also includes cap assembly that permits readily opening and closing the system without undue force or user strength. More desirably still, such a system includes an automated cooling system that terminates water flow at a specified time, once the sample has been determined to have reached a desired final temperature. 
     SUMMARY 
     A sample encapsulation system includes a base, a chamber having an inlet and a chamber housing in which the chamber is housed. The chamber is fixedly mounted at least in part within the chamber housing and the chamber housing is movably mounted to the base. 
     The system includes a cap, a first ram operably mounted to the cap for engaging the chamber inlet and a second ram positioned in the chamber opposite the inlet. The second ram is movable toward and away from the first ram. 
     The chamber and housing are movable toward the cap for engaging the first ram with the chamber inlet during an encapsulation cycle and away from the cap, disengaging the first ram from the chamber inlet following an encapsulation cycle. 
     In an embodiment, the cap can be formed as part of a cap assembly, in which the cap assembly includes a mounting plate, and the cap secures to mounting plate. The mounting plate is stationary relative to the housing and chamber. When the cap is secured to the mounting plate, the chamber and housing are movable toward the mounting plate for the first ram to engage the chamber inlet. The chamber and housing are movable away from the mounting plate to disengage the first ram from the chamber inlet. 
     The chamber can have a tapered wall section at about the inlet that expands outwardly toward the inlet. In such an arrangement, the first ram has a tapered profile for mating with the chamber inlet tapered wall. In an embodiment, the chamber inlet can be configured with a two-step tapered wall section. A first tapered wall section at the inlet transitions to a relatively straight-walled section that transitions to a second tapered wall section. The first ram can have a tapered wall for mating with the chamber second tapered wall section during the encapsulation cycle and for disengaging from the second tapered wall section following the encapsulation cycle. 
     In an embodiment, the chamber and/or chamber housing includes an inwardly oriented lip at a lower end thereof. The second ram engages the inwardly oriented lip following the encapsulation cycle to move the chamber and chamber housing away from the cap and to disengage the chamber inlet from the first ram. Disengaging the second ram from the inwardly oriented lip permits movement of the chamber housing and chamber toward the cap for engaging the chamber inlet with the first ram. 
     The cap can be movable toward and away from the mounting plate and can be locked to the mounting plate when in the encapsulation cycle. The cap is movable toward and away from the mounting plate along a post. A constant force spring can be operably connected to the cap for moving the cap toward and away from the mounting plate. 
     In an embodiment, the sample encapsulation system includes a base, a chamber and a chamber housing in which the chamber is housed. The chamber is fixedly mounted at least in part within the chamber housing and the chamber housing is movably mounted to the base. The system includes a cap. 
     A heating assembly and a cooling assembly are disposed about the chamber and a temperature sensor is mounted remotely from an interior of the chamber. The temperature sensor can be mounted to the chamber housing remote from an encapsulated sample within the chamber. The remote sensed temperature is used to continue or stop operation of the cooling system following a predetermined period of time after the remote sensed temperature reaches a set point temperature based upon a predicted temperature of the encapsulated sample as determined by the remote sensed temperature. 
     The system can include means for determining the predetermined period of time of cooling system operation. One such predetermined period of time is a time lag (Δt). For an encapsulated sample having a predetermined diameter Δt is determined according to the formula Δt=A+BT+Ct, where T is a hold temperature of the encapsulated sample in degrees C., t is a hold time in seconds at the hold temperature of the encapsulated sample and where A, B and C are experimentally determined factors based upon the set point temperature. 
     In one embodiment, for an encapsulated sample having a 1.0 to 1.25 inch diameter and a set point temperature of 40 degrees C., A is 6.73, B is 0.0783 and C is −0.0115 or at a set point temperature of 55 degrees C. A is −8.12, B is 0.130 and C is 0.00625t, or for an encapsulated sample having a 1.5 inch diameter and a set point temperature of 40 degrees C., A is 1.8, B is 0.320 and C is 0.604, or at a set point temperature of 55 degrees C., A is −29.0, C B is 0.367 and C is +0.0688t, or for an encapsulated sample having a 2.0 inch diameter and a set point temperature 40 degrees C., A is 1.125, B is 0.430T and C is 0.156t, or at a set point temperature of 55 degrees C., A is −52.9, B is 0.543 and C is 0.162. 
     The system can further include means for establishing the set point temperature, means for determining the lag time (Δt) for cooling fluid flow and means for stopping fluid cooling flow after the set point temperature has been reached and the lag time has expired. One such means for determining the lag time (Δt) for cooling fluid flow is based, at least in part, on a size of the sample and the set point temperature. One such means for determining the lag time (Δt) for cooling fluid flow is based, at least in part, on a diameter of the sample. 
     These and other features and advantages of the present disclosure will be apparent from the following detailed description, in conjunction with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying and drawings, wherein: 
         FIG. 1  is a perspective illustration of a sample preparation system with the chamber cap handle rotated to the open position and shown, in phantom in the locked position; 
         FIG. 2  is a front view illustration of the chamber portion of the system; 
         FIG. 3  is a partially cut-away view of the chamber portion; 
         FIG. 4  is a partial cross-sectional view of the chamber shown in the locked position; 
         FIG. 4A  is a partial sectional view of the plug when the chamber is locked; 
         FIG. 5  is a partial cross-sectional view of the chamber shown in the unlocked position; 
         FIG. 5A  is a partial sectional view of the plug when the chamber is unlocked; 
         FIG. 6  illustrates the lower part of the chamber when the chamber is in the unlocked position, showing no gap between the lower portion and spacers at the base; 
         FIG. 7  is an illustration similar to  FIG. 6 , showing the lower part of the chamber when the chamber is in the locked position, showing the gap between the lower portion and spacers at the base; 
         FIG. 8  is an illustration of the chamber cap mounting to the base; 
         FIG. 9  is an illustration of the lower part of the chamber housing showing the lower ram and various electrical and fluid connections to the housing; 
         FIG. 10  is a perspective illustration of the housing, chamber cap and constant force spring mounting of the cap to the base; 
         FIG. 11  is a cross-sectional view of the housing, chamber cap and constant force spring mounting of the cap to the base; and 
         FIG. 12  is a flow diagram showing one embodiment of a control scheme for the cooling system for the sample encapsulation system. 
     
    
    
     DETAILED DESCRIPTION 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the device and is not intended to be limited to the specific embodiment illustrated. 
     Referring now to the figures and in particular, to  FIGS. 1-3 , there is shown generally a sample preparation or encapsulation system  10 . The system  10  includes, generally, a base  12  having a chamber housing  14  with a chamber  16 , a chamber cap assembly  18  and a control system  20 . 
     The base  12  is a mounting system for the chamber housing  14 , chamber  16 , cap assembly  18  and control system  20 , and encloses these components. A control panel  22  is mounted on the base  12 . Electrical  24  and fluid  26  connectors extend into the base  12  and connect to the various components within the base  12 . 
     The chamber  16  is fixedly mounted within the chamber housing  14 . The housing  14  is mounted to the base  12  by columns or posts  28  and is moveable along the posts  28  toward and away from the base  12 . As such, as the housing  14  moves toward and away from the base  12 , the chamber  16  likewise moves toward and away from the base  12 . A biasing element  30 , such as the illustrated wave springs (Belleville washers) bias the chamber housing  14  away from the base  12 . A stop  32 , such as the illustrated shoulder screw, permits setting the distance from which the housing  14  can move away from the base  12 . The shoulder screw  32  height (distance from the base  12 ) can be adjustable. 
     The chamber  16  has a tapered or angled inlet as indicated at  34  (see  FIGS. 4A and 5A ). In a present embodiment, the inlet  34  has a two-step taper. A first or outer tapered wall section  36  at the immediate inlet  34  transitions to a straight-walled section  38 , which transitions to a second or inner tapered wall section  40 , which then transitions to another straight walled section  42  that defines the mold cavity  44 . In a present embodiment, the walls  36 ,  40  are tapered at an angle of about 7 degrees. An opposite end  46  of the chamber  16  includes an inwardly directed lip  48 . A fill guide  50  (see,  FIG. 3 ) is positioned at about the chamber inlet  34  to assist filling the chamber  16  with resin or other encapsulating material, which may be provided in granulated or powdered form. 
     The chamber housing  14  includes both a cooling system  52  and a heating system  54 . The heating system  54  includes one or more heating coils  56  within the chamber housing  14 , surrounding the chamber  16 . In a present embodiment, the heating coils, are electric heating coils, that are positioned around the chamber  16 . Contacts or connectors  58  provide for connecting power to the heating coils  56 . The cooling system  52  includes cooling coils  60 , such as liquid cooled coils that are positioned around within chamber housing  14 , surrounding the chamber  16 . One or more inlets and outlets  62  are positioned about the chamber housing  14  for supplying liquid to and carrying liquid from the coils  60 . A present system uses a water cooled system. 
     One or more temperature sensors  64  are positioned on the chamber housing  14 , outside of the pressure boundary, that is outside of the chamber  16 , to sense the temperature of the housing  14 . 
     The cap assembly  18  includes a cap mounting plate  66  disposed at an end of the chamber  16  opposite the base  12 . The mounting plate  66  can be mounted to, for example, an upper end of the posts  28 . The mounting plate  66  is fixed relative to the base  12 . In this configuration, the chamber housing  14  (and chamber  16 ) move toward and away from the mounting plate  66  or move between the base  12  and the mounting plate  66 . 
     The mounting plate  66  includes a securing assembly  68 , such as the illustrated bayonet mount, to secure a cap  70  to the mounting plate  66 . The cap  70  includes a cooperating securing assembly  72 , such as the illustrated mating bayonet, to secure the cap  70  to the mounting plate  66 . It will be understood that in this configuration, the cap  70  remains fixed to the mounting plate  66  which is stationary relative to the moving chamber housing  14  and chamber  16 . It will also be understood that any type of mount can be used to secure the cap  70  to the mounting plate  66  and that the bayonet mount is illustrative of one type of mount that can be used. 
     The cap  70  includes a first or upper ram  74  mounted thereto. The upper ram  74  is configured for insertion into the chamber  16  at the inlet  34  to establish a pressure boundary and forms one side or end of the mold cavity  44 . The upper ram  74  is mounted to the cap  70  by an adjustable element  76 , such as the illustrated threaded rod to allow for properly adjusting the seating of the upper ram  74  in the chamber  16 . 
     The upper ram  74  has a tapered wall  78  that mates with the chamber second tapered wall section  40 . Accordingly, in a present embodiment, the upper ram tapered wall  78  has a taper of about 7 degrees. 
     Referring to  FIGS. 8, 10 and 11 , the cap  70  is mounted to the base  12  by a post  80  that rides in a linear bearing  82  that, when the cap  70  is in the unlocked position, allows the cap  70  to be lowered and raised toward and away from the mounting plate  66 . The post  80  includes a cam lock arrangement  84  which permits the cap  70  to be held or maintained in the open position when fully retracted. In a present system, the cam lock  84  is configured as a pin  86  that engages a shoulder  88  on the housing  12 . In this manner, the cap  70  can be unlocked from the mounting plate  66  and raised, away from the plate  66 , to allow access to the chamber  16 . By rotating the cap  70  and post  80 , the cap  70  can be held in place in the open position with the pin  86  resting on the shoulder  88 . By rotating the cap  70  and post  80  in the opposite direction (so as to align with the chamber  16 ), the pin  86  can be disengaged from the shoulder  88  and the cap  70  lowered onto the plate  66 . A constant force spring  90 , such as the illustrated wound steel spring, facilitates raising and lowering the cap  70  with minimal force. The spring  90  has a force about equal to the weight of the cap  70 . 
     The system  10  includes a lower ram  92  disposed in the chamber  16 , opposite the upper ram  74 . In a present embodiment, the lower ram  92  is a hydraulic ram that is driven by a cylinder  94 , and moves upward toward the upper ram  74  when in the molding or encapsulation cycle, and downward, away from the upper ram  74  for loading the chamber  16  and when releasing an encapsulated sample. 
     In use, the cap  70  is opened and fully retracted. The cap  70  is then rotated with the post  80  so that the cap  70  is held open by the pin  86  resting on the shoulder  88 . At this point in time, the lower ram  92  is in the withdrawn position. When in the withdrawn position, the lower ram  92  engages the lip  48  at the bottom of the chamber  16  and draws the chamber  16  and chamber housing  14  downward, away from the cap mounting plate  66  and toward the base  12 . 
     A sample and encapsulating material are introduced into the chamber  16 . The cap  70  and post  80  are then rotated to disengage the pin  86  from the shoulder  88  and the cap  70  is lowered onto the mounting plate  66 . The cap  70  is then locked to the mounting plate  66  by rotating the handle  96  to engage the mating bayonet elements  68 ,  72 . The upper ram  74  is positioned in, but not fully engaged with the chamber inlet end  34  (see  FIG. 5A ). 
     The encapsulation cycle commences with the cylinder  94  actuating and the lower ram  92  moving up. As the lower ram  92  comes off of the lip  48 , the spring  30  that engages the chamber  16  and housing  14  urges the chamber housing  14  upward and moves the chamber inlet  34  fully into engagement with the upper ram  74  (see  FIG. 4A ). The upper ram taper  78  and the chamber second or inner tapered wall section  40  seal the ram  74  in the chamber  16 . Force up to about 12,000 pounds is exerted by the lower ram  92  moving into the chamber  16 , toward the upper ram  74 . 
     Heat is then applied to the chamber  16  by the heating system  54 , and the heat and pressure exerted by the lower ram  92  against the sample and encapsulation material, over a predetermined period of time, fuses the encapsulation material and the sample to form the encapsulated sample. 
     Following expiration of the predetermined period of time, the heating system  54  isolates and the cooling system  52  commences cooling of the sample. After reaching a predetermined temperature, the lower ram  92  withdraws or retracts. As the ram  92  retracts, it engages the lip  48 , which pulls or urges the chamber  16  and chamber housing  14  downward, toward the base  12  and away from the upper ram  74 . As the chamber  16  moves away from the upper ram  74 , the gap G formed between the upper ram  74  and the chamber second tapered wall section  40  facilitates more easily loosening the cap  70  from the mounting plate  66 . That is, by moving the upper ram  74  out of contact with the inner wall of the chamber inlet  34 , the cap  70  is readily removed from the chamber  16  and the cap  70  can be opened and the encapsulated sample removed. 
     As set forth above, the sample must be sufficiently cooled to permit handling, to ensure edge retention and to minimize any shrinking that may otherwise occur, so as to maintain the integrity of the sample. Prior known sample preparation systems use a timed system to cool the sample. That is, cooling water was run through the system for a predetermined period of time regardless of whether the desired temperature was reached. It will be appreciated that it is difficult, at best, to directly monitor or measure the temperature of the sample during the cooling step. Thus, if the desired temperature was not achieved and the sample was too hot, it may lack integrity and may be difficult to handle. Conversely, if the cooling system ran too long, then cooling water was wasted. 
     The present sample encapsulation system  10  uses a novel system in which a remotely measured temperature is sensed and, based upon the measured temperature, the time at which the encapsulated sample will reach a desired temperature is determined. This provides a higher degree of assurance that the sample has been cooled to a temperature that allows comfortable handling and provides a high degree of encapsulated sample integrity. 
     In a present system, cooling liquid flow, in the present embodiment, cooling water flow, is controlled based upon the remotely measured temperature in conjunction with empirically derived relations. The temperature of the housing  14 , outside the pressure boundary or chamber  16 , is measured by a temperature sensing device  64 , such as a thermocouple, a thermistor, a resistance temperature detector (RTD), an infrared sensor or the like. A present system uses a RTD that is mounted to the chamber housing  14  to measure the temperature of the outer surface of the chamber housing. 
     Testing was conducted to determine the time profiles to a comfortable handling temperature for various samples of encapsulated samples, after the housing temperature had reached a predetermined temperature. Four different sizes (diameters) of samples were tested: 1.0 inch, 1.25 inches, 1.5 inches and 2.0 inches. The samples all consisted of ½ inch diameter steel balls encapsulated in resin. Each of the samples was heated to a predetermined temperature (T in degrees C.) and held at that temperature for a predetermined period of time (t in seconds). The time lag (Δt in seconds) between when the housing reached a target temperature T t  of 40 degrees C. (104° F.) and the sample reached the target temperature T t  of 40 degrees C. was then measured. The data is provided in Table 1, below. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 TEST DATE FOR VARIOUS SAMPLE SIZES AT VARYING 
               
               
                 HOLD TEMPERATURES AND HOLD TIMES AND SAMPLE 
               
               
                 TO HOUSING COOLING LAG TIMES 
               
             
          
           
               
                 Sample 
                 Mold size 
                 Hold Temp 
                 Hold Time 
                 Time Diff - 
               
               
                 No. 
                 (in.) 
                 (° C.) 
                 (sec) 
                 Δt (sec) 
               
               
                   
               
             
          
           
               
                 1 
                 1.00 
                 100 (212° F.) 
                 60 
                 12 
               
               
                 2 
                 1.00 
                 100 
                 180 
                 15 
               
               
                 3 
                 1.00 
                 100 
                 300 
                 12 
               
               
                 4 
                 1.00 
                 200 (392° F.) 
                 60 
                 27 
               
               
                 5 
                 1.00 
                 200 
                 180 
                 25 
               
               
                 6 
                 1.00 
                 200 
                 300 
                 18 
               
               
                 7 
                 1.25 
                 100 
                 60 
                 9 
               
               
                 8 
                 1.25 
                 100 
                 180 
                 12 
               
               
                 9 
                 1.25 
                 100 
                 300 
                 15 
               
               
                 10 
                 1.25 
                 200 
                 60 
                 21 
               
               
                 11 
                 1.25 
                 200 
                 180 
                 18 
               
               
                 12 
                 1.25 
                 200 
                 300 
                 13 
               
               
                 13 
                 1.50 
                 100 
                 60 
                 49 
               
               
                 14 
                 1.50 
                 100 
                 180 
                 39 
               
               
                 15 
                 1.50 
                 100 
                 300 
                 46 
               
               
                 16 
                 1.50 
                 200 
                 60 
                 58 
               
               
                 17 
                 1.50 
                 200 
                 180 
                 82 
               
               
                 18 
                 1.50 
                 200 
                 300 
                 90 
               
               
                 19 
                 2.00 
                 100 
                 60 
                 40 
               
               
                 20 
                 2.00 
                 100 
                 180 
                 73 
               
               
                 21 
                 2.00 
                 100 
                 300 
                 88 
               
               
                 22 
                 2.00 
                 200 
                 60 
                 97 
               
               
                 23 
                 2.00 
                 200 
                 180 
                 109 
               
               
                 24 
                 2.00 
                 200 
                 300 
                 133 
               
               
                   
               
             
          
         
       
     
     In testing, it was found that changes in coolant (water) flow rate did not significantly impact Δt, so long as the flow rate was between about 0.8 liters per minute (0.8 l/min or 0.21 gal/min) and 1.9 l/min (0.50 gal/min). In addition, it was also found that changes in coolant inlet temperature did not significantly impact Δt, so long as coolant inlet temperature was between about 17 degrees C. (62.6° F.) and 25 degrees C. (77° F.). 
     The data was then plotted and algorithms were developed for each of the sample sizes (diameters). It was found that the algorithms for the 1.00 inch and 1.25 inch samples were the same (Eq. 1). The algorithms for the 1.50 and 2.00 inch diameter samples were different from the small sample algorithm and from each other (Eq. 2—1.50 inch sample; Eq. 3—2.00 inch sample). 
     For the 1.00 and 1.25 inch diameter samples, it was found that the time lag or Δt between when the housing reached a target temperature T t  of 40 degrees C. (104° F.) and the sample reached the target temperature T t  of 40 degrees C. is defined by:
 
Δ t= 6.73+0.0783 T− 0.0115 t,   (Eq. 1)
 
Where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample.
 
     For the 1.50 inch diameter sample, it was found that the time lag or Δt between when the housing reached a target temperature T t  of 40 degrees C. and the sample reached he target temperature T t  of 40 degrees C. is defined by:
 
Δ t= 1.8+0.320 T+ 0.604 t,   (Eq. 2)
 
Again, where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample.
 
     For the 2.00 inch diameter sample, it was found that the time lag or Δt between when the housing reached a target temperature T t  of 40 degrees C. and the sample reached the target temperature T t  of 40 degrees C. is defined by:
 
 Δt= 1.125+0.430 T+ 0.156 t,   (Eq. 3)
 
Once again, where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample.
 
     It has also been found that a target temperature T t  of 55 degrees C. (131° F.) is acceptable for both sample integrity and comfortable sample handling. Accordingly, testing was carried out to determine the time lag or Δt between when the housing reached a target temperature T t  of 55 degrees C. (131° F.) and the sample reached the target temperature T t  of 55 degrees C. The lime lag or Δt was found to be defined by:
 
Δ t =(−8.12)+0.130 T+ 0.00625 t,   (Eq. 4)
 
where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample for 1.00 inch and 1.25 inch diameter encapsulated samples; and
 
 Δt =(−29.0)+0.367 T+ 0.0688 t,   (Eq. 5)
 
where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample for a 1.50 inch diameter encapsulated sample; and
 
 Δt =(−52.9)+0.5430 T+ 0.162 t,   (Eq. 6)
 
where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C. and t is the hold time in seconds at temperature T of the sample for a 2.0 inch diameter sample.
 
     Accordingly, it has been found that for any target temperature T t , the time lag or Δt between when the housing reaches the target temperature T t  and when the sample reaches the target temperature T t  can be determined experimentally by:
 
Δ t=A+BT+Ct,   (Eq. 7)
 
where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C., t is the hold time in seconds at temperature T of the sample, and A, B and C are experimentally determined factors.
 
     A method for making an encapsulated sample using an encapsulation system  10  in which a sample is encapsulated in a medium includes introducing a sample to be encapsulated and the encapsulating medium into a chamber  16 . A temperature external of the chamber  16  is monitored by a sensor  64 . In a present method, the temperature of the outer surface of the chamber housing  14  is monitored. 
     The sample and medium are then subjected to heat and pressure at a predetermined temperature and pressure for a predetermined period of time, the time being a hold time. Following the hold time, the encapsulated sample is cooled using a cooling fluid. In a present method, the cooling fluid is water that is circulated around the outer surface of the chamber, between the chamber and the chamber housing, and the temperature at an outer surface of the housing is monitored. 
     Upon reaching a predetermined temperature, the target temperature T t , as monitored external of the chamber  16 , a time lag (Δt) is established for a period of time to continue cooling fluid flow to cool the encapsulated sample. The time lag (Δt) is determined according to the formula:
         Δt=A+BT+Ct, where Δt is the lag time in seconds, T is the hold temperature of the sample in degrees C., t is the hold time in seconds at temperature T of the sample, and A, B and C are experimentally determined factors.       

     For 1.00 inch and 1.25 inch diameter encapsulated samples and a target temperature T t  of 40 degrees C., the time lag (Δt) is determined according to the equation Δt=6.73+0.0783T−0.0115t; for a 1.50 inch diameter encapsulated sample and a target temperature of 40 degrees C., the time lag (Δt) is determined according to the equation Δt=1.8+0.320T+0.604t; and for a 2.00 inch diameter encapsulated sample and a target temperature 40 degrees C., the time lag (Δt) is determined according to the equation Δt=1.125+0.430T+0.156t. 
     For 1.00 inch and 1.25 inch diameter encapsulated samples for a target temperature T t  of 55 degrees C., the time lag (Δt) is determined according to the equation Δt=(−8.12)+0.130T+0.00625t; for a 1.50 inch diameter encapsulated sample and a target temperature T t  of 55 degrees C., the time lag (Δt) is determined according to the equation Δt=(−29.0)+0.367T+0.0688t; and for a 2.00 inch diameter encapsulated sample and a target temperature T t  of 55 degrees C., the time lag (Δt) is determined according to the equation Δt=(−52.9)+0.5430T+0.162t. 
     Thus, by knowing the size of the encapsulated sample, the temperature T at which it is held and time period t over which it is held at that temperature, and by remotely monitoring the temperature of the system  10 , for example, at an outer surface of the chamber housing  14 , and by applying certain parameters, the time Δt at which the encapsulated sample will reach a target temperature T t  equal to the temperature of the outer surface of the housing, and at which the sample can be removed from the system  10  so as to maintain its integrity and to be comfortably handled can be determined. 
     Referring to  FIG. 12 , there is shown an embodiment of a cooling system operating scheme  102  for the sample encapsulation system. The operation of the cooling system  52  is integrated into the overall encapsulating system operating scheme and is controlled by the controller  20 . The size of the encapsulated sample is input to the system through the control panel  22 —again, this is done in conjunction with the overall operating scheme. 
     Following the encapsulation cycle, at block  104  the temperature at the remote location, presently at the outside of the chamber housing  16  is monitored. If the temperature is greater than the target temperature T t  in degrees C., Δt is calculated by use of equation 7, based on the size of the encapsulated sample and the target temperature T t , a countdown timer (equal to Δt) is set, and the cooling system is set to run for 180 seconds at blocks  106  and  108 . 
     The temperature continues to be monitored at block  110  and if it is greater than the target temperature T t , cooling continues. Once the temperature is monitored at less than the target temperature T t , the countdown timer starts at block  113 . If the countdown timer (Δt) has not expired, the cooling system continues to operate (line at  114 ). Once the countdown timer has expired (as block  112 ), cooling is complete and the cooling system stops at block  116 . 
     Those skilled in the art will recognize the programming necessary to effectuate operation of the control system, and will appreciate the numerous other ways in which the system controls can operate. 
     All patents and patent applications referred to herein, are incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
     In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
     From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present disclosure. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover all such modifications as fall within its scope.