Systems and methods for sealing food container

Abstract

A system for sealing food containers comprises: a frame, a first sealing tool mounted to the frame at least at a first mounting point so as to be supported by the frame and a second sealing tool. The first and second sealing tools are configured to be pressed together in order to seal a food container positioned therebetween. At least one strain gauge is configured to measure the force transmitted through the frame as the first and second sealing tools are pressed together, the at least one strain gauge being attached to the frame.

1 . A system for sealing food containers, the system comprising:
 a frame;   a first sealing tool mounted to the frame at least at a first mounting point so as to be supported by the frame;   a second sealing tool, the first and second sealing tools being configured to be pressed together in order to seal a food container positioned therebetween;   at least one strain gauge configured to measure the force transmitted through the frame as the first and second sealing tools are pressed together, the at least one strain gauge being attached to the frame.   
     
     
         2 . A system according to  claim 1 , wherein the second sealing tool is mounted to the frame at a second mounting point so as to be supported by the frame. 
     
     
         3 . A system according to  claim 2 , wherein the frame comprises one or more frame elements defining at least a first closed loop, wherein the first and second sealing tools are mounted such that a force is transmitted through the closed loop as the first and second sealing tools are pressed together, and wherein the strain gauge is attached to the frame at a position along the closed loop. 
     
     
         4 . A system according to  claim 3 , wherein the first closed loop defines a plane that is substantially parallel to the direction along which the first and second sealing tools are pressed together. 
     
     
         5 . A system according to  claim 4 , wherein the first and second sealing tools are each mounted to the one or more frame elements defining the first closed loop at different positions around the closed loop, preferably substantially opposite to one another around the closed loop. 
     
     
         6 . A system according to  claim 3 , wherein at least a first of the frame elements that define the first closed loop is detachable from the other frame elements defining the first closed loop, wherein the at least one strain gauge is attached to said first frame element. 
     
     
         7 . A system according to  claim 1 , wherein the at least one strain gauge is attached to a part of the frame extending substantially parallel to the direction along which the first and second sealing tools are configured to be pressed together. 
     
     
         8 . A system according to  claim 1 , wherein the at least one strain gauge is attached to a part of the frame substantially in pure tension as the first and second sealing tools are pressed together. 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . A system according to any of the preceding claims  claim 1 , wherein one of the first and second sealing tools is coupled to an actuator for moving said sealing tool in order to bring the first and second sealing tools together so as to be pressed together. 
     
     
         16 . (canceled) 
     
     
         17 . A system according to  claim 15 , wherein the first or second sealing tool that is coupled to the actuator is mounted to the frame via the actuator, such that the force exerted by the actuator when the first and second sealing tools are pressed together is transmitted to the frame. 
     
     
         18 . A system according to  claim 15 , further comprising a controller configured to control the actuator, wherein the controller is connected to the at least one strain gauge and is configured to control the actuator based on measurements of the at least one strain gauge, wherein preferably the controller is configured to control the actuator such that a peak measurement by the at least one strain gauge falls within a predetermined range or exceeds a predefined target. 
     
     
         19 . A system according to  claim 18 , wherein the actuator comprises a crank driven by a crankshaft for moving the first or second sealing tool, wherein the first and second sealing tools are configured such that the crank does not reach top dead centre when the first and second sealing tools are pressed together. 
     
     
         20 . A system according to  claim 15 , wherein the actuator comprises a motor. 
     
     
         21 . (canceled) 
     
     
         22 . A system according to  claim 20 , wherein the motor comprises a torque sensor configured to measure the motor torque. 
     
     
         23 . A system according to  claim 15 , further comprising an encoder for measuring displacement of the actuator. 
     
     
         24 . A system according to  claim 15 , wherein the first or second sealing tool comprises a tool body and one or more sealing portions movable relative to the tool body, wherein in a first movement phase the actuator is configured to bring the first sealing tool into contact with the second sealing tool, and wherein in a second movement phase the actuator is configured to cause the one or more sealing portions to move relative to the tool body so as to press the one or more sealing portions of said sealing tool against the other of the first and second sealing tools. 
     
     
         25 . A system according to  claim 1 , further comprising a controller, wherein the controller is connected to the at least one strain gauge and is configured to output an indication that the system is defective when a peak measurement by the at least one strain gauge as the first and second sealing tools are pressed together falls above or below a predetermined value, preferably when the peak measurement falls outside of a predetermined. 
     
     
         26 . A system according to  claim 22 , further comprising a controller, wherein the controller is connected to the at least one strain gauge, and is further connected to the torque sensor, and wherein the controller is configured to output an indication that the system is defective based on the measurements of the strain gauge and the measurements of the torque sensor, wherein preferably the controller is configured to output an indication that the system is defective based on a comparison of the measurements of the at least one strain gauge with the measurements of the torque sensor across a plurality of sealing cycles. 
     
     
         27 . A system according to  claim 1 , wherein one of the first and second sealing tools is an upper tool and the other of the first and second sealing tools is a lower tool, wherein the lower tool is configured to receive and hold a container for sealing and the upper tool is configured to seal a lid, preferably a film lid, on the container. 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . A method of sealing food containers comprising:
 providing a food container to be sealed between a first sealing tool and a second sealing tool, the first sealing tool being mounted to a frame at least at a first mounting point so as to be supported by the frame;   pressing the first and second sealing tools together so as to seal the food container positioned therebetween;   measuring a force transmitted through the frame as the first and second sealing tools are pressed together using at least one strain gauge attached to the frame.   
     
     
         32 . (canceled)