Temperature control method and apparatus

Abstract

The invention relates to a method of cooling machines. Typically, the method of cooling is useful in the cooling of dies used in the moulding of plastics or metals. The method relies upon taking advantage of the latent heat of vaporisation of a cooling liquid. A liquid is maintained in a closed chamber in a die such that the liquid is in contact with the surfaces to be cooled and a space above the liquid surface is available. The pressure in the space is adjusted, typically by vacuum equipment, such that the boiling point of the liquid is adjusted to a level which enables the principle cooling process to involve latent heat.

1 . A temperature control apparatus configured to uniformly cool a molding surface of a mold or die comprising:
 a molding surface;   at least one completely closed chamber having air substantially removed therefrom;   a single quantity of liquid in said at least one completely closed chamber wherein said single quantity of liquid extends to cover at least one area adjacent to and on an opposite side of the molding surface of said mold;   wherein said molding surface comprises a separating wall or walls having a uniform thickness through all of the wall or walls through which cooling is effected;   wherein a level of the liquid is sufficient to cover all of said at least one area including said separating wall or walls of the at least one completely closed chamber from which heat is to be taken and wherein each of said at least one completely closed chamber is integrated within the mold;   a space above the single quantity of liquid and within the at least one completely closed chamber in which pressure within the space is caused to be set at a level which enables the single quantity of liquid to boil into a vapor at a selected temperature, said selected temperature being at a level such that the selected temperature is below a temperature of the at least one area adjacent to the molding surface; and,   a condenser configured to cool the vapor to a selected cooling temperature, wherein condensation of the vapor returns condensed vapor to the single quantity of liquid.   
     
     
         2 . The apparatus as claimed in  claim 1  wherein the single quantity of liquid is water. 
     
     
         3 . The apparatus as claimed in  claim 1  further comprising:
 at least one heating element located within the at least one completely closed chamber and within the single quantity of liquid such that during standby time, temperature of the mold or die is kept within a selected temperature range. 
 
     
     
         4 . A temperature control apparatus configured to uniformly cool a molding surface of a mold or die comprising:
 a molding surface;   at least one completely closed chamber having air substantially removed therefrom;   a single quantity of liquid in said at least one completely closed chamber wherein said single quantity of liquid extends to cover at least one area adjacent to and on an opposite side of the molding surface of said mold;   wherein said molding surface comprises a separating wall or walls having a uniform thickness through all of the wall or walls through which cooling is effected;   wherein a level of the liquid is sufficient to cover all of said at least one area including said separating wall or walls of the at least one completely closed chamber from which heat is to be taken and wherein each of said at least one completely closed chamber is integrated within the mold;   wherein said at least one completely closed chamber is configured such that if there is a temperature differential between any two locations within the at least one completely closed chamber, the single quantity of fluid boils at a location with a higher temperature and a resultant vapor condenses at a location with a lower temperature, in order to maintain a uniform temperature throughout the at least one completely closed chamber; and,   a space above the single quantity of liquid and within the at least one completely closed chamber in which pressure within the space is caused to be set at a level which enables the single quantity of liquid to boil into the vapor at a selected temperature, said selected temperature being at a level such that the selected temperature is below a temperature of the at least one area adjacent to the molding surface.   
     
     
         5 . The apparatus as claimed in  claim 4  further comprising:
 a condenser configured to cool the vapor to a selected cooling temperature, wherein condensation of the vapor returns condensed vapor to the single quantity of liquid. 
 
     
     
         6 . A temperature control apparatus configured to uniformly cool a molding surface of a mold or die comprising:
 at least one adjacent closed chamber adjacent to the molding cavity;   a separating wall or walls between the molding cavity and the at least one adjacent closed chamber having a uniform thickness through all of the wall or walls through which cooling is effected;   wherein said at least one adjacent closed chamber comprises a liquid to an extent to effect substantial exclusion of any other fluid, so that there is both a liquid portion and a saturated vapor portion of the said liquid within the at least one adjacent closed chamber and only this liquid;   wherein a level of the liquid is sufficient to cover all of at least one area including said wall or walls of the chamber from which heat is to be taken; and,   a condenser coupled with the at least one adjacent closed chamber.   
     
     
         7 . The apparatus as claimed in  claim 6 , wherein the fluid is a single selected fluid. 
     
     
         8 . The apparatus as claimed in  claim 6  wherein said mold or die comprises two molds or dies configured to fit together and hold an item to be formed. 
     
     
         9 . The apparatus as claimed in  claim 6 , wherein said at least one adjacent closed chamber adjacent to the molding cavity is within the mold. 
     
     
         10 . The apparatus as claimed in  claim 8 , wherein said at least one adjacent closed chamber adjacent to the molding cavity is within the mold. 
     
     
         11 . The apparatus as claimed in  claim 8 , wherein the level of the liquid portion is sufficient to cover an area or areas of the said wall or walls of the chamber from which heat is to be taken, and within the space above the liquid portion of the fluid, such space containing substantially only the vapor of the fluid, the pressure in the space thereby being substantially equal to the vapor pressure of the fluid which results in, upon there being a temperature differential between any portion of the surface of the wall or walls and a cooler portion of the surface of the wall or walls within the space, some liquid of the fluid boiling at the said higher temperature location and effecting thereby removal of heat as latent heat of vaporization from the higher temperature location through a phase conversion of the fluid to a vapor and thereafter effecting, by condensation of the vapor which effects release of its latent heat of vaporization at said lower temperature location in the space above the said liquid to reduce said temperature differential and, by condensation of vapor at the condenser which is cooled from time to time so as to control the temperature of the fluid to be within a selected range. 
     
     
         12 . The apparatus as claimed in  claim 10 , wherein the level of the liquid portion is sufficient to cover an area or areas of the said wall or walls of the chamber from which heat is to be taken, and within the space above the liquid portion of the fluid, such space containing substantially only the vapor of the fluid, the pressure in the space thereby being substantially equal to the vapor pressure of the fluid which results in, upon there being a temperature differential between any portion of the surface of the wall or walls and a cooler portion of the surface of the wall or walls within the space, some liquid of the fluid boiling at the said higher temperature location and effecting thereby removal of heat as latent heat of vaporization from the higher temperature location through a phase conversion of the fluid to a vapor and thereafter effecting, by condensation of the vapor which effects release of its latent heat of vaporization at said lower temperature location in the space above the said liquid to reduce said temperature differential and, by condensation of vapor at a condenser which is cooled from time to time so as to control the temperature of the fluid to be within a selected range. 
     
     
         13 . The apparatus as claimed in  claim 6 , wherein the level of the liquid portion is sufficient to cover an area or areas of the said wall or walls of the chamber from which heat is to be taken, and within the space above the liquid portion of the fluid, such space containing substantially only the vapor of the fluid, the pressure in the space thereby being substantially equal to the vapor pressure of the fluid which results in, upon there being a temperature differential between any portion of the surface of the wall or walls and a cooler portion of the surface of the wall or walls within the space, some liquid of the fluid boiling at the said higher temperature location and effecting thereby removal of heat as latent heat of vaporization from the higher temperature location through a phase conversion of the fluid to a vapor and thereafter effecting, by condensation of the vapor which effects release of its latent heat of vaporization at said lower temperature location in the space above the said liquid to reduce said temperature differential and, by condensation of vapor at a condenser which is cooled from time to time so as to control the temperature of the fluid to be within a selected range. 
     
     
         14 . The apparatus as claimed in  claim 13 , further comprising an element configured to control a passage of coolant through the condenser so as to maintain the temperature of the fluid within a selected range.