Drug Heating Cycle Limiter For Injection Device

Abstract

An injection assembly includes a dispensing chamber housing, a temperature control device, a thermal sensor, a switch, and a controller. The dispensing chamber housing has an inner surface and an outer surface. The inner surface partially defines a dispensing chamber for receiving a quantity of a substance. The temperature control device at least partially surrounds the dispensing chamber housing and alters a temperature of a substance in the dispensing chamber. The thermal sensor is located near the temperature control device and reads a temperature near the temperature control device. The switch is coupled to the temperature control device. The controller controls the temperature control device and the switch such that a first voltage is applied to the temperature control device until the temperature control device reaches a desired temperature, and a second voltage is applied to the temperature control device thereafter to maintain the temperature control device at the desired temperature.

1 . A dispensing assembly comprising:
 a dispensing chamber housing having an inner surface and an outer surface, the inner surface partially defining a dispensing chamber for receiving a quantity of a substance;   a temperature control device at least partially surrounding the dispensing chamber housing, the temperature control device for altering a temperature of a substance in the dispensing chamber;   a thermal sensor located near the temperature control device, the thermal sensor for reading a temperature near the temperature control device; and   a controller for controlling the temperature control device such that the substance in the dispensing chamber is not exposed to elevated temperature nor overexposed to heat.   
   
   
       2 . The assembly of  claim 1  wherein the controller counts a number of times the temperature control device is activated. 
   
   
       3 . The assembly of  claim 2  wherein the controller disables a tip segment if the number of times the temperature control device is activated exceeds a set number. 
   
   
       4 . The assembly of  claim 1  wherein the controller times a period when the temperature control device is activated. 
   
   
       5 . The assembly of  claim 4  wherein the controller shuts off the temperature control device when the period when the temperature control device is activated exceeds a set period. 
   
   
       6 . The assembly of  claim 1  further comprising:
 a switch coupled to the temperature control device.   
   
   
       7 . The assembly of  claim 6  wherein the controller controls the switch such that a first voltage is applied to the temperature control device until the temperature control device reaches a desired temperature, and a second voltage is applied to the temperature control device thereafter to maintain the temperature control device at the desired temperature. 
   
   
       8 . The assembly of  claim 1  wherein the temperature control device is a heater comprising a resistive element. 
   
   
       9 . An injection assembly comprising:
 a dispensing chamber housing having an inner surface and an outer surface, the inner surface partially defining a dispensing chamber for receiving a quantity of a substance;   a temperature control device at least partially surrounding the dispensing chamber housing, the temperature control device for altering a temperature of a substance in the dispensing chamber;   a thermal sensor located near the temperature control device, the thermal sensor for reading a temperature near the temperature control device;   a switch coupled to the temperature control device; and   a controller for controlling the temperature control device;   wherein the controller controls the switch such that a first voltage is applied to the temperature control device until the temperature control device reaches a desired temperature, and a second voltage is applied to the temperature control device thereafter to maintain the temperature control device at the desired temperature.   
   
   
       10 . The assembly of  claim 9  wherein the controller counts a number of times the temperature control device is activated. 
   
   
       11 . The assembly of  claim 10  wherein the controller disables a tip segment if the number of times the temperature control device is activated exceeds a set number. 
   
   
       12 . The assembly of  claim 9  wherein the controller times a period when the temperature control device is activated. 
   
   
       13 . The assembly of  claim 12  wherein the controller shuts off the temperature control device when the period when the temperature control device is activated exceeds a set period. 
   
   
       14 . The assembly of  claim 9  wherein the temperature control device is a heater comprising a resistive element. 
   
   
       15 . A method of operating a dispensing assembly comprising:
 checking a count of a number of times a temperature control device has been activated;   if the count does not exceed a preset number, incrementing a counter;   applying a first voltage across a temperature control device to bring the temperature control device to a desired temperature;   after the temperature control device reaches the desired temperature, applying a second voltage across the temperature control device to maintain the temperature control device at the desired temperature;   starting a timer to count the amount of time that the temperature control device is activated; and   if the amount of time that the temperature control device is activated exceeds a preset amount of time, turning off the temperature control device.   
   
   
       16 . The method of  claim 15  further comprising:
 if the count exceeds a preset number, then disabling a tip segment so that an injection cannot be performed.   
   
   
       17 . The method of  claim 15  wherein applying a first voltage across a temperature control device to bring the temperature control device to a desired temperature further comprises controlling a switch to apply the first voltage. 
   
   
       18 . The method of  claim 17  wherein applying a second voltage across a temperature control device to bring the temperature control device to a desired temperature further comprises controlling a switch to apply the second voltage. 
   
   
       19 . The method of  claim 18  wherein starting a timer to count the amount of time that the temperature control device is activated further comprises starting the timer when the switch is controlled to apply the second voltage. 
   
   
       20 . The method of  claim 15  wherein starting a timer to count the amount of time that the temperature control device is activated further comprises starting the timer after the temperature control device has reached the desired temperature.