Method for determining the liquid level in a boiler
First Claim
1. A method of determining a level of a liquid in a boiler of an apparatus having a temperature sensor for sensing a temperature (T) which is indicative of a temperature of the liquid inside the boiler, comprising the acts of:
- inducing a temporary deflection of the temperature (T) sensed by the temperature sensor;
determining an evaluation temperature (Tev) sensed by the temperature sensor directly after inducing the deflection, wherein the evaluation temperature (Tev) is one of a maximum temperature (Tmax) of the liquid inside the boiler after turning off a heating device including a temperature overshoot and a temperature decrease after reaching the maximum temperature (Tmax) depending on the level of the liquid inside the boiler and a minimum temperature (Tmin) of the liquid inside the boiler after filling the boiler including a temperature undershoot and a temperature increase after reaching the minimum temperature (Tmin) depending on the level of the liquid inside the boiler; and
determining the level of the liquid inside the boiler from at least the evaluation temperature (Tev),wherein the inducing act includes an act of turning on the heating device for heating the liquid to induce the temporary deflection of the temperature (T), wherein the temporary deflection is an increase in the temperature T),wherein the act of determining an evaluation temperature (Tev) includes the acts of;
monitoring the increase in the temperature (T) by the temperature sensor;
turning off the heating device when the temperature is greater that a first threshold temperature (Tth1); and
saving the maximum temperature (Tmax) of the liquid inside the boiler as the evaluation temperature (Tev) when the temperature (T) decreases after the act of turning off the heating device, andwherein the act of determining the level of the liquid includes one of the acts of;
determining the level of the liquid to be low when the evaluation temperature (Tev) is greater than a first low level threshold (Tlow1); and
determining the level of the liquid to be low when a difference between the evaluation temperature (Tev) and the first threshold temperature (Tth1) is greater than or equal to a second low level threshold (Tlow2), andwherein the method further comprises the act of pumping water into the boiler when the act of determining the level of the liquid indicates that the level of the liquid inside the boiler is low.
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Abstract
A method for determining a liquid level in a boiler of an apparatus having a temperature sensor for sensing a temperature which is indicative of a temperature of the liquid inside the boiler, includes inducing a temporary deflection of the temperature sensed by the temperature sensor; determining an evaluation temperature sensed by the temperature sensor after inducing the deflection; and determining the liquid level from at least the evaluation temperature. The evaluation temperature is determined by monitoring the deflection and by defining an extreme value of the deflection as the evaluation temperature.
38 Citations
12 Claims
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1. A method of determining a level of a liquid in a boiler of an apparatus having a temperature sensor for sensing a temperature (T) which is indicative of a temperature of the liquid inside the boiler, comprising the acts of:
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inducing a temporary deflection of the temperature (T) sensed by the temperature sensor; determining an evaluation temperature (Tev) sensed by the temperature sensor directly after inducing the deflection, wherein the evaluation temperature (Tev) is one of a maximum temperature (Tmax) of the liquid inside the boiler after turning off a heating device including a temperature overshoot and a temperature decrease after reaching the maximum temperature (Tmax) depending on the level of the liquid inside the boiler and a minimum temperature (Tmin) of the liquid inside the boiler after filling the boiler including a temperature undershoot and a temperature increase after reaching the minimum temperature (Tmin) depending on the level of the liquid inside the boiler; and determining the level of the liquid inside the boiler from at least the evaluation temperature (Tev), wherein the inducing act includes an act of turning on the heating device for heating the liquid to induce the temporary deflection of the temperature (T), wherein the temporary deflection is an increase in the temperature T), wherein the act of determining an evaluation temperature (Tev) includes the acts of; monitoring the increase in the temperature (T) by the temperature sensor; turning off the heating device when the temperature is greater that a first threshold temperature (Tth1); and saving the maximum temperature (Tmax) of the liquid inside the boiler as the evaluation temperature (Tev) when the temperature (T) decreases after the act of turning off the heating device, and wherein the act of determining the level of the liquid includes one of the acts of; determining the level of the liquid to be low when the evaluation temperature (Tev) is greater than a first low level threshold (Tlow1); and determining the level of the liquid to be low when a difference between the evaluation temperature (Tev) and the first threshold temperature (Tth1) is greater than or equal to a second low level threshold (Tlow2), and wherein the method further comprises the act of pumping water into the boiler when the act of determining the level of the liquid indicates that the level of the liquid inside the boiler is low. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification