Method and device for controlling the temperature of the gas flow in medical devices
Inventors
Menzel, Felix • Zeyßig, Andreas • KOERNER, Johannes
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12023446-B2
Publication Date
2024-07-02
Expiration Date
Abstract
A method is provided for controlling the gas temperature in medical devices by means of a state observer, e.g., in the field of laparoscopy or respiration, and to devices for carrying-out said method.
Core Innovation
The invention relates to a method for measuring and controlling gas temperature in an insufflator for laparoscopy. A gas is supplied by a gas supply device through a supply line to a patient, and the gas volume flow is controllable between 0 and 50 l/min. The gas is heated from room temperature to a desired temperature of 32-42° C within the gas supply hose.
When changing the gas volume flow, a time span until the desired temperature is reached is a maximum of 100 s. Heating occurs by a heating wire, and temperature measurement is made by measuring a resistance of the heating wire such that the heating wire used for heating and for performing the temperature measure are a single element. The heating power of the heating wire is electrically controlled.
The resistance of the heating wire is used as an input variable of a mathematical estimation system that describes a state space. The mathematical estimation system estimates the actual temperature at the exit of the hose and controls the heating power of the heating wire by means of this estimated value. The mathematical estimation system is configured as a Luenberger observer.
Claims Coverage
The independent claim identifies a method, with several dependent claims narrowing the gas type, providing an example target temperature, specifying a form of electrical control, and extending the method to an insufflator apparatus implemented by electronics including a microprocessor, memory, and software. The inventive features are organized around: using a heating wire for both heating and resistance-based temperature measurement, using a state-space mathematical estimation system implemented as a Luenberger observer to estimate exit temperature, and using the estimated exit temperature to control heating power within specified hose heating and flow conditions.
Heating within the gas supply hose to 32-42° C
Gas is supplied to a patient by a gas supply device via a supply line with controllable gas volume flow between 0 and 50 l/min, and the gas is heated from room temperature to a desired temperature of 32-42° C within the gas supply hose.
Single-element temperature measurement using heating wire resistance
Heating occurs by a heating wire, and temperature measurement is made by measuring a resistance of the heating wire such that the heating wire used for heating and for performing the temperature measure are a single element.
State-space temperature estimation with Luenberger observer
The resistance of the heating wire is an input variable of a mathematical estimation system that mathematically describes a state space, estimates the actual temperature at the exit of the hose, and is configured as a Luenberger observer.
Heating power control based on estimated hose exit temperature
The heating power of the heating wire is electrically controlled, and the heating power is controlled by means of the estimated value of the actual temperature at the exit of the hose produced by the mathematical estimation system.
Across the independent claim, the core coverage centers on using the heating wire as both heater and resistance sensor, estimating the actual gas exit temperature with a state-space mathematical estimation system configured as a Luenberger observer, and controlling the heating power based on the estimated exit temperature while heating the gas in the supply hose to 32-42° C under specified gas flow and heating time constraints.
Stated Advantages
Achieving exit-temperature precision without an additional temperature sensor by using the heating wire resistance as a single-element measurement while controlling heating power based on an estimated exit temperature.
Providing faster control versus conventional pre-control, as reflected in the stated maximum time span until the desired temperature is reached (maximum of 100 s) when changing gas volume flow.
Documented Applications
An insufflator for laparoscopy that supplies gases to a patient with a gas supply hose containing a heating wire, configured to measure and control gas temperature according to the method.
Interested in licensing this patent?