A liquid level control method for a ceramic liquid level sensor

Abstract

The present invention provides a liquid level control method of a ceramic liquid level sensor, which can be used for monitoring the liquid level and is not affected by the water quality and conductivity of the liquid. The method comprises the following steps: manufacturing a liquid level sensor, firstly processing a ceramic core, wherein a heating element is provided inside the ceramic core to form a heating end of the ceramic core, wherein the heating element is made of a metal material with a positive temperature coefficient, wherein the heating element is connected to the pin end of the ceramic core, wherein the pin end is connected to a power supply and a controller through a wiring harness, wherein the controller can read the current value in the heating element, and the liquid level can be determined by determining the magnitude of the current and the set current during monitoring.

Description

Technical Field

[0001] The invention relates to the technical field of liquid level detection, and in particular to a liquid level control method of a ceramic liquid level sensor. Background Art

[0002] The liquid level sensor can be used to monitor the liquid level in the container, so that the liquid replenishment device can be adjusted according to the liquid level for replenishment. At present, household appliances involving automatic liquid replenishment control mainly rely on mechanical float sensors to detect the height of the liquid level in the corresponding container or device. Specifically, when the liquid level in the controller is lower than the lower limit, the float falls to trigger the lower liquid level detection circuit, which is fed back to the controller to start replenishing liquid into the container or device; when the liquid level in the controller is higher than the upper limit, the float rises to trigger the upper liquid level detection circuit, which is fed back to the controller, and the water tank stops replenishing liquid into the container or device. When the float is in the middle position, the upper and lower liquid level detection circuits are open, and the liquid level controller does not work. The working principle of the float type liquid level detection component is simple, but it has extremely high requirements for water quality. If there are impurities in the liquid or as the working years increase, the impurities will slowly accumulate, resulting in the float being blocked from floating up and down, thereby affecting the accuracy of liquid level height control, causing the corresponding equipment to fail to work. There are also sensors that use the conductive principle of liquid to determine the liquid level (two electrodes are placed in a container, and when the liquid level rises, the electrodes conduct and it is determined that the liquid level has reached a specified position). However, the use scenarios of this type of sensor are limited by the conductivity of the liquid. Taking water as an example, if there are relatively more impurities, the water level can be determined. However, for cleaner water quality (such as ultrapure water), conduction cannot be achieved, and misjudgment will occur.

[0003] In order to prevent the liquid level sensor from being affected by water quality and liquid conductivity, the applicant's earlier patent application with application number 2022228568862 introduced a liquid level sensor, in which a heating element made of a metal material with a positive temperature coefficient is wrapped by a ceramic material to isolate the liquid. At the same time, the temperature changes with the contact with the liquid affect the resistance of the heating element, so that the liquid level can be monitored according to the current value. However, it does not record how to control the liquid replenishing device through the liquid level sensor. Summary of the invention

[0004] In view of the problem that traditional liquid level sensors are easily affected by water quality and liquid conductivity, the present invention provides a ceramic liquid level sensor liquid level control method, which can be used for liquid level monitoring. It can adjust the liquid replenishing device according to the liquid level sensor, and the liquid level sensor is not affected by the water quality and conductivity of the liquid.

[0005] The technical scheme is as follows: a liquid level control method of a ceramic liquid level sensor, characterized in that it includes the following steps: manufacturing a liquid level sensor, first processing a ceramic core, the ceramic core has a heating element inside to form a heating end of the ceramic core, the heating element is made of a metal material with a positive temperature coefficient, the heating element is connected to the pin end of the ceramic core, the pin end is connected to a power supply and a controller through a wiring harness, and the controller can read the current value in the heating element;

[0006] Before liquid level monitoring, install the liquid level sensor 1 for monitoring the lower limit liquid level and the liquid level sensor 2 for monitoring the upper limit liquid level in the container whose liquid level needs to be monitored respectively, heat the ceramic core by loading the rated voltage U on the pin end and make its temperature higher than the liquid temperature, adjust the liquid level to the lower limit liquid level and ensure that the bottom end of the heating end of the ceramic core of the liquid level sensor 1 is located below the lower limit liquid level. When the current value is stable, record the current value at this time as I down, adjust the liquid level to the upper limit liquid level and ensure that the top end of the heating end of the ceramic core of the liquid level sensor 2 is located above the upper limit liquid level. When the current value is stable, record the current value at this time as I up;

[0007] During liquid level monitoring, the rated voltage U is applied to the liquid level sensor 1 and the liquid level sensor 2 respectively, and the current values ​​in the heating elements of the liquid level sensor 1 and the liquid level sensor 2 are respectively monitored by the controller and recorded as I1 and I2;

[0008] When I1 is less than I down and I2 is less than I up, it is determined that the liquid level is below the lower limit liquid level, and the controller controls the liquid replenishing device to replenish liquid at a speed of V1;

[0009] When I1 is greater than or equal to I lower and I2 is less than I upper, it is determined that the liquid level is above the lower limit liquid level and below the upper limit liquid level, and the controller controls the liquid replenishing device to replenish liquid at a speed V2, and the speed V2 is less than the speed V1;

[0010] When I1 is greater than I lower and I2 is greater than or equal to I upper, it is determined that the liquid level is above the upper limit liquid level, and the controller stops the liquid replenishing device from replenishing liquid.

[0011] It is further characterized by:

[0012] The liquid level sensor also includes a hollow shell, the ceramic core is installed in the shell, a slot is opened on the side of the shell, the uppermost end of the slot is at a certain distance from the top of the shell, the part above the slot in the shell is sealed, the pin end of the ceramic core is located above the slot, the pin end is connected to the power supply and the controller through a wiring harness passing through the shell, and the heating end of the ceramic core extends to the slot or extends to below the slot.

[0013] Beneficial effect: Since the length of time the heating end is immersed in the liquid will change the temperature of the ceramic core, thereby causing the resistance of the heating element to change, the liquid level can be monitored by monitoring the output current through the controller. At the same time, the opening and closing of the liquid replenishing device or the liquid replenishing speed can be adjusted according to different liquid levels, and the function of automatic liquid replenishment can be realized, which is not affected by the water quality and conductivity of the liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the pin position of the ceramic chip core;

[0015] Figure 2 is a schematic diagram of the location of the heating element;

[0016] Figure 3 This is a schematic diagram of the installation of the liquid level sensor;

[0017] Figure 4 This is a schematic diagram of the installation positions of the liquid level sensor 1 and the liquid level sensor 2;

[0018] Figure 5 This is the workflow diagram for controlling fluid replacement. DETAILED DESCRIPTION

[0019] A liquid level control method for a ceramic liquid level sensor comprises the following steps: manufacturing a liquid level sensor, firstly processing a liquid level sensor through a multilayer ceramic processing process, Figure 1 , Figure 2 The ceramic core 1 shown has a heating element 2 inside to form the heating end of the ceramic core 1. The heating element 2 is made of a metal material with a positive temperature coefficient (the resistance increases with increasing temperature, such as platinum). The heating element 2 is formed by printing a slurry (such as platinum slurry) on the ceramic core 1 and then sintering them together. The heating element 2 is connected to the pin end 3 of the ceramic core 1 (formed by printing a conductive slurry on the ceramic core and sintering it). The ceramic core is placed in a shell to form a liquid level sensor 4. The pin end 3 is connected to a power supply and a controller (such as a PLC controller) through a wiring harness 6, and the controller can read the current value in the heating element.

[0020] Combination Figure 3 As shown, the ceramic core 1 is vertically loaded into a hollow cylindrical shell 8, the ceramic core 1 is installed in the shell 8, a slot 9 is opened on the side of the shell 8, the upper end of the slot 9 is at a certain distance from the top 8 of the shell, the part above the slot 9 in the shell 8 is sealed, the pin end 3 of the ceramic core 1 is located above the slot 9, the pin end 3 is connected to the power supply and the controller through the wiring harness 6 passing through the shell 8, and the heating end of the ceramic core 1 extends to the slot 9 or extends to below the slot 9. In this way, when the liquid level rises, due to the liquid sealing principle, the highest liquid level in the shell will only be located at the upper end of the slot 9, thereby avoiding the pin end 3 from contacting the liquid and protecting the pin end 3.

[0021] like Figure 4 As shown, before liquid level monitoring, the liquid level sensor 10 for monitoring the lower limit liquid level and the liquid level sensor 2 11 for monitoring the upper limit liquid level are respectively installed vertically in the container whose liquid level needs to be monitored through the limit sealing device 7 (various fixed installation modes: thread, lock, latch, etc.), and the ceramic core 1 is heated by loading the rated voltage U on the pin end 3 to make its temperature higher than the liquid temperature, and the liquid level is adjusted to the lower limit liquid level and ensure that the bottom end of the heating end of the ceramic core of the liquid level sensor 10 is located below the lower limit liquid level. When the current value is stable, the current value at this time is recorded as I down, and the liquid level is adjusted to the upper limit liquid level and ensure that the top end of the heating end of the ceramic core of the liquid level sensor 2 11 is located above the upper limit liquid level. When the current value is stable, the current value at this time is recorded as I up.

[0022] During liquid level monitoring, the rated voltage U is applied to the liquid level sensor 10 and the liquid level sensor 2 11 respectively, and the current values ​​in the heating elements of the liquid level sensor 10 and the liquid level sensor 2 11 are respectively monitored by the controller and recorded as I1 and I2.

[0023] Combination Figure 5 As shown, the controller first determines the relationship between the current values ​​I1 and Idown, and I2 and Iupper. When I1 is less than Idown and I2 is less than Iupper, it is determined that the liquid level is below the lower limit level, and the controller controls the liquid replenishing device to replenish the liquid at a faster speed V1. As the liquid level rises, the liquid will gradually approach the chip core inside the sensor. The liquid will immerse the chip core in a few seconds and reduce the temperature of the heating end, thereby reducing the resistance of the heating element and gradually increasing the current. The current value I1 of the lower limit sensor is higher than the threshold within a few seconds. The control circuit determines that the liquid level is above the lower limit and below the upper limit, and then sends a work instruction to the system. At the same time, the storage device will replenish the liquid into the working device at a slower speed V2.

[0024] If I1 is greater than or equal to Ilower and I2 is less than Iupper, it is determined that the liquid level is above the lower limit liquid level and below the upper limit liquid level. The controller controls the liquid replenishing device to directly replenish liquid at a speed of V2. At this time, it can work normally and a work instruction can be issued through the controller. The speed V2 is less than the speed V1. The speed V2 is slightly faster than the liquid consumption speed during work, ensuring that the work does not stop due to the liquid level being too low.

[0025] If I1 is greater than I lower and I2 is greater than or equal to I upper, it is determined that the liquid level is above the upper limit liquid level. The controller stops the liquid replenishing device from replenishing liquid and issues a work instruction at the same time. As the liquid level drops until I2 is less than I upper, the liquid is replenished at a slower speed V2.

[0026] When replenishing fluid and working at the speed V2 at the same time, if it is monitored that I1 is less than I down, replenish fluid at the speed V1 again. If it is monitored that I2 is greater than or equal to I up, replenish fluid. Overall, the replenishment speed is flexibly adjusted according to the relationship between I1 and I down, and I2 and I up.

[0027] Through the above method, automatic circulation and refilling can be achieved by monitoring the liquid level. When the power supply provides the rated voltage, the chip heating resistor provides heat energy to the sensor. The sensor can work normally in the temperature range of room temperature to 400℃. The external ceramic core can protect the heating element, and the liquid level sensor will not be affected by the water quality and conductivity of the liquid.

[0028] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by anyone familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A liquid level control method for a ceramic liquid level sensor, characterized in that: It includes the following steps: To make a liquid level sensor, a ceramic core is first processed. A heating element is provided inside the ceramic core to form a heating end of the ceramic core. The heating element is made of a metal material with a positive temperature coefficient. The heating element is connected to the pin end of the ceramic core. The pin end is connected to a power supply and a controller through a wiring harness. The controller can read the current value in the heating element. Before liquid level monitoring, install the liquid level sensor 1 for monitoring the lower limit liquid level and the liquid level sensor 2 for monitoring the upper limit liquid level in the container where the liquid level needs to be monitored. Heat the ceramic core by applying the rated voltage U to the pin end and make its temperature higher than the liquid temperature. Adjust the liquid level to the lower limit liquid level and ensure that the bottom of the heating end of the ceramic core of the liquid level sensor 1 is below the lower limit liquid level. When the current value is stable, record the current value at this time as I 下 , adjust the liquid level to the upper limit and ensure that the top of the heating end of the ceramic core of the second liquid level sensor is above the upper limit. When the current value stabilizes, record the current value at this time as I 上 ; During liquid level monitoring, the rated voltage U is applied to the liquid level sensor 1 and the liquid level sensor 2 respectively, and the current values ​​in the heating elements of the liquid level sensor 1 and the liquid level sensor 2 are respectively monitored by the controller and recorded as I1 and I2; When I1 is less than I 下 , I2 is less than I 上 When the liquid level is determined to be below the lower limit liquid level, the controller controls the liquid replenishing device to replenish liquid at a speed of V1; When I1 is greater than or equal to I 下 , I2 is less than I 上 When the liquid level is determined to be above the lower limit liquid level and below the upper limit liquid level, the controller controls the liquid replenishing device to replenish liquid at a speed V2, and the speed V2 is less than the speed V1; When I1 is greater than I 下 , I2 is greater than or equal to I 上 When the liquid level is determined to be above the upper limit liquid level, the controller stops the liquid replenishing device from replenishing liquid.

2. A liquid level control method of a ceramic liquid level sensor according to claim 1, characterized in that: The liquid level sensor also includes a hollow shell, the ceramic core is installed in the shell, a slot is opened on the side of the shell, the uppermost end of the slot is at a certain distance from the top of the shell, the part above the slot in the shell is sealed, the pin end of the ceramic core is located above the slot, the pin end is connected to the power supply and the controller through a wiring harness passing through the shell, and the heating end of the ceramic core extends to the slot or extends to below the slot.

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