Thermic infusion system dry tube detector
Inventors
McCoy, James Kevin • Smothermon, Jared A.
Assignees
Publication Number
US-11707580-B2
Publication Date
2023-07-25
Expiration Date
2037-09-08
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
A method for improved controlling of a thermic infusion system having a one tubal segment and a thermal element to heat an infusion fluid carried within the tubal segment, and having at least one sensor positioned within the thermic infusion system comprising regulating energy provided to the sensor for a first period of time to sense a self-heating effect of the at least one sensor due to a dry tube; responsive to detecting a dry tube, preventing energizing the thermal element; responsive to detecting a non-dry tube, regulating energy provided to the sensor for a second period of time to sense a temperature of an infusion fluid carried within the at least one tubal segment.
Core Innovation
The invention provides a thermic infusion system designed to detect when the infusion tube is dry (contains no fluid) and take remedial action to prevent unwanted heating. The system employs one or more thermistor sensors within the tubing, which exhibit a predictable self-heating error. When voltage and current are applied to a thermistor for a longer period, the sensor heats itself, and this self-heating is greater when the tubing is dry, as there is no fluid thermal mass to absorb the heat. The system detects this characteristic increase in sensor temperature to determine the absence of fluid in the tube.
If a dry tube condition is detected, the electronic control unit responds by regulating energy to the thermal element, effectively preventing unwanted energizing or overheating of the heater. Conversely, when fluid is detected in the tubing, voltage and current are applied for a much shorter period, which allows the system to accurately sense the actual fluid temperature with minimal self-heating error. This method utilizes the self-heating error phenomenon in thermistor sensors, traditionally considered undesirable, to reliably discriminate between wet and dry tubing conditions.
The problem addressed by this invention is the risk of accidentally heating an infusion tube when it is not filled with fluid, which can result in wasted battery energy and potential thermal damage to the device or surrounding items. Existing systems do not adequately detect dry tube conditions, especially with transparent infusates, and may inadvertently overheat the tubing. The disclosed invention automatically detects a dry tube state and triggers user alerts and/or disables or reduces heater operation to enhance safety and device reliability.
Claims Coverage
The patent claims cover two main inventive features, each defined in independent claims comprising both a system and a method for dry tube detection and remedial action in a thermic infusion system.
Thermal infusion system with dry tube detection using thermistor self-heating error
A thermic infusion system includes a thermal tubing system with at least one tubal segment, an electronic control unit, and at least one thermistor sensor positioned within the tubing. The thermistor sensor exhibits a predictable self-heating error. The electronic control unit is configured to: - Apply voltage and current to the thermistor sensor for a first period (long enough to produce and sense the self-heating error when the tube contains no fluid thermal mass) - Apply voltage and current for a second, shorter period (to sense temperature without producing self-heating error when the tube contains fluid) - Determine tube dryness based on the sensed self-heating error and temperature - Respond to a dry tube condition by regulating energy to the thermal element to implement at least one remedial action, such as preventing heater energization or issuing user alerts
Method of controlling a thermic infusion system based on thermistor self-heating error analysis
A method of controlling a thermic infusion system comprising: 1. Applying voltage and current to at least one thermistor sensor for a first period, long enough to sense a predictable self-heating error when the tubal segment contains no fluid 2. Applying voltage and current for a second, shorter period to sense the infusion fluid temperature without self-heating error when the tube contains fluid 3. Determining, using the analyzed self-heating error and temperature, whether the tube is dry 4. Regulating, in response to dryness determination, the amount of energy provided to the thermal element to implement at least one remedial action (such as disabling heater power or issuing an alert)
These inventive features cover both the apparatus and method for detecting a dry infusion tube in a thermic infusion system using thermistor self-heating error, and taking responsive actions to enhance safety and functional control.
Stated Advantages
The invention prevents unnecessary or dangerous heating of an infusion tube when no fluid is present, enhancing patient safety and device reliability.
Automatic detection of dry tube conditions avoids wasting battery energy due to unnecessary heating.
The system reliably distinguishes between dry and wet tubing without relying on optical methods, which may not work with transparent infusates, improving effectiveness in varied conditions.
Remedial actions, including alerts and power control, are automatically triggered, reducing the need for user intervention and mitigating operator error.
Documented Applications
Warming intravenous fluids (such as blood, plasma, or resuscitative fluids) to physiological beneficial temperature ranges for trauma patients.
Use in medical applications including dialysis systems, chemotherapy systems, and blood exchange systems to safely heat or cool infusates.
Industrial applications such as petrochemical, chemical processing, pharmaceutical processing, and food processing, using the system to efficiently heat and/or cool flowing fluids or gases.
Interested in licensing this patent?