Valve pin with thermocouple

Abstract

A valve pin for use in a melt channel in an injection molding machine. The valve pin has a valve pin body and at least one thermocouple substantially completely inside the valve pin body.

1. A valve pin for use in a melt channel in  of an injection molding machine  nozzle having a nozzle heater, comprising:
 a valve pin body; and  
 at least one thermocouple positioned substantially completely inside  coupled to said valve pin body for measuring the temperature of melt in said melt channel, wherein the temperature measurement is used in controlling said nozzle heater.  
 
     
     
       2. A valve pin as claimed in  claim 1 , wherein said at least one thermocouple includes a sensing portion and a pair of electrical conduits for connecting said sensing portion to a receiving device. 
     
     
       3. A valve pin as claimed in  claim 2 , wherein said valve pin body has an end that is adapted to be positioned proximate a gate into a mold cavity, and said sensing portion of said at least one thermocouple is positioned in said end. 
     
     
       4. A valve pin as claimed in  claim 3 , wherein said sensing portion of said at least one thermocouple is adapted to be exposed to melt when said valve pin body is positioned in said melt channel. 
     
     
       5. A valve pin as claimed in  claim 4 , wherein said sensing portion of said at least one thermocouple is flush with said end. 
     
     
       6. A valve pin as claimed in  claim 2 , wherein said valve pin includes a first said thermocouple and a second said thermocouple, and said sensing portion of said first thermocouple is spaced from said sensing portion of said second thermocouple. 
     
     
       7. A valve pin as claimed in  claim 6 , wherein said valve pin body has an end that is adapted to be positioned proximate a gate into a mold cavity, and said sensing portion of said first thermocouple is positioned proximate said end. 
     
     
       8. A valve pin as claimed in  claim 1  further comprising an actuator for moving said valve pin body in said melt channel. 
     
     
       9. The valve pin as claimed in  claim 8 , wherein said valve pin body is removably connected to said actuator. 
     
     
       10. A nozzle for an injection molding machine, comprising:
 a nozzle body defining a nozzle melt channel therein, wherein said nozzle melt channel is adapted to transfer melt from a melt source,  to a gate into a mold cavity;  
 a heater connected to said nozzle body, wherein said heater is located on said nozzle body for heating melt passing through said nozzle melt channel; 
 a valve pin positioned at least partially in said nozzle melt channel, said valve pin including a valve pin body and at least one valve pin thermocouple positioned at least partially within said valve pin body for measuring the temperature of the melt in said nozzle melt channel, wherein the temperature measurement is used in controlling said nozzle heater; and  
 an actuator for moving said valve pin in said melt channel.  
 
     
     
       11. A nozzle as claimed in  claim 10 , further comprising:
 a heater connected to said nozzle body, and wherein said heater is located on said nozzle body for heating melt passing through said nozzle melt channel; and 
 a nozzle body thermocouple connected to said nozzle body.  
 
     
     
       12. A nozzle as claimed in  claim 10 , wherein said actuator includes a chamber and a piston that is movable within said chamber, wherein said valve pin is connected to said piston, said piston has two faces, and said piston is adapted to be moved in said chamber by differential pressure of an actuating fluid in said chamber on said two faces of said piston. 
     
     
       13. A nozzle as claimed in  claim 10 , wherein said valve pin is removably connected to said actuator. 
     
     
       14. The valve pin as claimed in  claim 1 , wherein said thermocouple is positioned at least partially within said valve pin body. 
     
     
       15. An injection molding machine comprising:
   a manifold having a manifold melt channel for receiving a melt stream;        a nozzle having a nozzle melt channel for receiving the melt stream from said manifold melt channel and delivering the melt stream to a mold cavity; and        a valve pin slidable within the manifold and nozzle melt channels, said valve pin having a valve pin body with a thermocouple, wherein said valve pin thermocouple is positionable within said manifold melt channel for measuring a temperature of the melt therein.     
     
     
       16. The injection molding machine as claimed in  claim 15 , wherein said valve pin thermocouple is positionable within said nozzle melt channel for measuring a temperature of the melt therein. 
     
     
       17. The injection molding machine as claimed in  claim 16 , wherein the mold cavity receives melt from a plurality of mold gates. 
     
     
       18. An injection molding machine comprising:
   a nozzle having a nozzle melt channel for receiving a melt from a melt source and delivering the melt to a mold cavity via a mold gate;        a valve pin slidable within the nozzle melt channel;        a first thermocouple with a sensing portion coupled proximate a forward end of said valve pin; and        a second thermocouple with a sensing portion coupled to said valve pin and spaced from said sensing portion of said first thermocouple.     
     
     
       19. The injection molding machine as claimed in  claim 18 , wherein the forward end of said valve pin is adapted to be seated in the mold gate and the sensing portion of the first thermocouple measures a temperature of the melt proximate the mold gate. 
     
     
       20. The injection molding machine as claimed in  claim 19 , wherein the sensing portion of the second thermocouple is positioned on a central portion of said valve pin for measuring a temperature of the melt proximate a central portion of said nozzle melt channel.