JP2011237240A - Scale detection sensor and scale detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scale detection sensor and a scale detection method which are capable of determining a failure of a sensor correctly with just two water level sensors and which indicate a cause of the failure as adhesion of scale.SOLUTION: A scale detection sensor is provided which detects a generation of scale in a tank 1 with two water level sensors having electrodes. A scale-resistant sensor 2 is provided by coating the electrode of the water level sensor with a conductive resin. The water level sensor whose electrode is not coated with a conductive resin is used as a scale detection sensor 3. The scale-resistant sensor 2 and the scale detection sensor 3 are installed at the same height inside the tank 1. A failure of the water level sensor and a generation of scale are detected with a decrease of electrical conduction of the scale detection sensor 3.

Description

  The present invention mainly relates to a scale detection sensor and a scale detection method capable of detecting a scale attached to a water level sensor or an electrode surface of an electric water heater.

  The water heater is equipped with a number of devices having electrodes, such as a water level sensor for detecting the water level in the hot water tank. When electrodes are installed in water, scale-derived components (ionic silica, hardness components, etc.) generated by the electrolysis action migrate to the (-) electrode, and a part of them is deposited and settled on the electrode. It is known to stick as a scale.

  When this scale adheres to the water level sensor, malfunctions such as malfunctions and abnormal stops of various devices occur, such as the accuracy of water level measurement being reduced. Therefore, conventionally, in order to determine the failure of a water level sensor, a plurality of water level sensors are shifted up and down, and a determination method or apparatus for determining abnormality of each water level sensor based on signals from all the sensors. Has been proposed.

  In the determination method of Patent Document 1, a plurality of water level detection bars are set to have different heights, and when any of the water level detection bars changes in an output signal of ON → OFF or OFF → ON, the water level is detected. If the detection rod is determined to be normal and this normal water level detection rod is used as a reference water level detection rod, and an ON signal is output from a higher water level detection rod than the reference water level detection rod, the upper water level detection rod is abnormal. It is the method of judging.

  Moreover, the confirmation apparatus of patent document 2 is an apparatus which judges that one of the water level detection rods has failed when the output signals of the water level detection rods are inconsistent in three or more water level detection rods. That is, even though the low water level detection rod outputs the OFF signal, the higher water level detection rod outputs the ON signal, and thus it is determined that there is a failure.

Japanese Patent No. 2885086 JP 58-9029 A

  However, since these conventional determination methods and apparatuses require at least three water level sensors, installation and maintenance of the water level sensor require a lot of labor and cost.

  In addition, even if three or more water level sensors are installed, it is assumed that all the water level sensors may fail at the same time if the scale adhesion rate is the same. If all the water level sensors are in failure as described above, some of the water level sensors cannot be determined to be abnormal, so that the failure determination means is not accurate.

  Furthermore, even if a conventional determination method or apparatus can determine whether or not some of the water level sensors have failed, it cannot immediately determine whether the cause of the failure is due to scale adhesion or another cause. . In other words, when the water level sensor fails due to the scale, it is necessary to pay attention to the adhesion of the scale to devices having other electrodes. However, in the conventional determination method and apparatus, since the water level sensor of the same material is used, it is difficult to immediately determine that the cause of the failure is a scale.

  Therefore, the present invention has been created to solve the above-mentioned problems, and it is possible to accurately determine a sensor failure with only two water level sensors, and the cause of the failure is adhesion of scale. Therefore, it is an object of the present invention to provide a scale detection sensor and a scale detection method capable of paying attention to devices having other electrodes.

  In order to achieve the above-mentioned object, the first means in the present invention is a scale detection sensor for detecting the generation of scale in the tank 1 by two water level sensors provided with electrodes, and the electrodes of the water level sensor are electrically conductive. A scale-resistant sensor 2 coated with resin and a scale detection sensor 3 in which a conductive resin is not coated on the electrode of the water level sensor are provided, and the scale-resistant sensor 2 and the scale detection sensor 3 are the same in the tank 1. It is installed at a height so as to detect an abnormality of the water level sensor and generation of scale in the tank 1 due to a decrease in electrical continuity in the sensor 3 for detecting the scale.

  The scale-resistant sensor 2 of the second means has an electrode coated with a fluororesin having conductivity.

  The scale detection method of the third means is a scale detection method for detecting the occurrence of scale in the tank 1 with a water level sensor equipped with an electrode, and is a scale-resistant sensor 2 in which a conductive resin is coated on the electrode of the water level sensor. And a sensor 3 for detecting the scale in which the electrode of the water level sensor is not coated with conductive resin in the tank 1, and an abnormality of the water level sensor and a scale in the tank due to a decrease in conductivity in the sensor 3 for detecting the scale. Detecting the occurrence is a means for solving the problem.

  As in claim 1 of the present invention, the scale detection sensor 3 and the scale-resistant sensor 2 are installed at the same height inside the tank 1, and when the electrical continuity in the scale detection sensor 3 decreases, an abnormality of the water level sensor is detected. It will be done. At this time, since the scale-resistant sensor 2 is coated with conductive resin and suppresses the adhesion of the scale, the scale adheres to the water level sensor of the same material at the same time as in the past. There is no longer a risk of making a decision.

  In addition, the scale-resistant sensor 2 can suppress the adhesion of the scale and extend the life of the water level sensor. From the comparison with the scale-resistant sensor 2, the abnormality of the scale detection sensor 3 is caused by the scale. The probability of that will increase. As a result, it is possible to pay attention to the adhesion of scales to devices having other electrodes.

  Further, as described in claim 2, by using a fluororesin having conductivity as the conductive resin, highly stable conductive performance can be maintained.

  Further, according to the scale detection method of the third aspect, since the scale detection sensor 3 is detected from an abnormality of the scale detection sensor 3 and the scale generation in the tank from the decrease in conductivity in the scale detection sensor 3, It is possible to detect the scale generation time for various devices.

It is the schematic which shows one Example of this invention sensor. It is a flowchart which shows the detection process of this invention sensor.

  According to the present invention, only two water level sensors can accurately determine the failure of the sensor, and it is understood that the cause of the failure is the adhesion of the scale, and attention should be paid to devices having other electrodes. Realized the original purpose of being able to pay.

  An embodiment of the present invention will be described below with reference to the drawings. The sensor of the present invention is used as, for example, a water level sensor installed in a hot water tank of an electric water heater.

  That is, it is a sensor that basically detects the water level in the tank 1 with two water level sensors provided with electrodes. Furthermore, simultaneously with the detection of the water level, the abnormality of the water level sensor and the occurrence of scale in the tank 1 are detected.

  The water level sensor used for the sensor of the present invention is composed of a scale-resistant sensor 2 and a scale detection sensor 3.

  The scale resistant sensor 2 is a scale resistant sensor 2 in which a conductive resin is coated on an electrode of a water level sensor. As this conductive resin, use of a fluororesin having conductivity is highly reliable.

  On the other hand, the scale detection sensor 3 is a scale detection sensor 3 in which the electrode of the water level sensor is not coated with conductive resin. That is, a general water level sensor is used as the scale detection sensor 3.

  These water level sensors may be any type as long as they have electrodes in the tank 1, and the shape and usage of the sensors can be changed depending on the situation.

  The scale-resistant sensor 2 and the scale detection sensor 3 are installed at the same height inside the tank 1 (see FIG. 1). In the illustrated example, a hot water supply tank of an electric water heater is shown. A heater 4 is installed inside the tank 1, and a controller 5 controls the heater 4, the scale-resistant sensor 2, and the scale detection sensor 3.

  When the electrical continuity of the scale detection sensor 3 installed in this way decreases, the controller 5 determines that the water level sensor is abnormal. At the same time, it is detected that scale has occurred in the tank 1.

  FIG. 2 shows a detection process of the scale-resistant sensor 2 and the scale detection sensor 3. That is, when the scale-resistant sensor 2 does not detect the water level, “abnormally low water level detection” occurs, and the controller 5 stops the operation of the water heater. On the other hand, when the scale detection sensor 3 does not detect the water level, “scale detection” occurs and the controller 5 issues an alarm.

  The detection method of the present invention is a method of using the sensor of the present invention, and is a method of detecting abnormality of the water level sensor and generation of scale in the tank from the decrease in conductivity in the sensor 3 for scale detection. Therefore, the installation position of the scale resistant sensor 2 and the scale detection sensor 3 of the sensor of the present invention may be installed at the same height in the tank 1 as in the sensor of the present invention, but the installation position is arbitrarily changed. It is also possible to do. For example, the scale generation can be detected at an early stage by setting the position of the scale detection sensor 3 at a position where the scale is more likely to be generated than the position of the scale-resistant sensor 2. Further, as shown in the drawing, in addition to using a sensor in which the scale-resistant sensor 2 and the scale detection sensor 3 are separately provided, a detection method using a sensor in which these are integrally provided is also possible.

  The temperature control device of the present invention is not limited to the illustrated example, and design changes can be freely made without changing the gist of the present invention.

  According to the present invention, it has been described mainly as a water level sensor installed in a hot water supply tank of an electric water heater, but the type of tank 1 and the use of the water level sensor are not limited to the embodiments, but other uses. It can also be used.

1 Tank 2 Scale Resistance Sensor 3 Scale Detection Sensor 4 Heater 5 Controller

Claims (3)

  A scale detection sensor that detects the occurrence of scale in a tank with two water level sensors equipped with electrodes. The scale level sensor has a conductive resin coated on the electrode of the water level sensor, and a conductive sensor on the electrode of the water level sensor. A scale detection sensor that is not coated with resin is provided, and the scale-resistant sensor and the scale detection sensor are installed at the same height inside the tank. And a scale detection sensor that is provided to detect the occurrence of scale in the tank.   The scale detection sensor according to claim 1, wherein the scale-resistant sensor includes an electrode coated with a fluororesin having conductivity.   A scale detection method for detecting the occurrence of scale in a tank with a water level sensor equipped with an electrode, wherein a scale-resistant sensor in which a conductive resin is coated on the electrode of the water level sensor and a conductive resin on the electrode of the water level sensor. A scale detection method characterized in that an uncoated scale detection sensor is installed in a tank and an abnormality of a water level sensor and generation of scale in the tank are detected from a decrease in conductivity in the scale detection sensor.

Images