Drug Heating Cycle Limiter For Injection Device
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.