System for monitoring liquid temperature and liquid level

Abstract

The invention provides a system for monitoring a liquid temperature and a liquid level. The system comprises a main pipeline, a liquid level detection module, a partition board, and a pressure transmission pipe, wherein the front end of the pressure transmission pipe is immersed into a water tank and the pressure transmission pipe is connected with the partition board in a sealed manner; the liquid level detection module comprises a shell and the shell is internally provided with a deformation membrane, a guide piston and a capacitance assembly; the deformation membrane covers the back open end of a corrugated pipe and the front open end of the corrugated pipe is fixed to the main pipeline; a pressure cavity for sensing liquid level pressure is defined by the partition board, the corrugated pipe and the deformation membrane; the back end of the pressure transmission pipe is inserted into the pressure cavity; the capacitance assembly comprises a fixed capacitance plate fixed on the shell and a movable capacitance plate connected with the shell through a spring; the movable capacitance plate is close to or far away from the fixed capacitance plate under the deformation effect of the deformation membrane; a capacitive reactance between the fixed capacitance plate and the movable capacitance plate is output to a signal processor; and the capacitive reactance is converted into a water tank liquid level by the signal processor. The system for monitoring the liquid temperature and the liquid level, provided by the invention, has the advantages of application to various liquid, no influences on components of liquid to be detected, capability of realizing stepless continuous measurement on the liquid level, and long service life.

Description

technical field [0001] The invention relates to a liquid temperature and liquid level measurement and control system. Background technique [0002] At present, most of the liquid level sensing systems widely used in the market are electrode type, series resistance type and traditional capacitive type. The antifreeze system used also mostly uses electric heating belts, pipes are emptied, etc. The main problems are as follows: [0003] 1. It cannot really achieve anti-scaling and adhesion of suspended solids in the liquid to be tested, so it is easy to cause its service life to be very short due to factors such as dirt in the liquid to be tested and electrochemical corrosion. At the same time, because its measurement depends on the Due to the good conductivity of the liquid, there is still a high requirement for the conductivity of the measured liquid. For liquids with different conductivity, the measurement results of the series resistance type will have large errors, or even...

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Problems solved by technology

[0003] 1. It cannot really achieve anti-scaling and adhesion of suspended solids in the liquid to be tested, so it is easy to cause its service life to be very short due to factors such as dirt in the liquid to be tested and electrochemical corrosion. At the same time, because its measurement depends on the Due to the good conductivity of the liquid, there is still a high requirement for the conductivity of the measured liquid. For liquids with different conductivity, the measurement results of the series resistance type will have large errors, or even the measurement results are wrong, so it is not suitable for replacement. Level measurement of multiple liquids

[0004] Second, the corrosion resistance is poor, which also affects the service life. Due to the influence of scaling and corrosion, there will be serious drift errors or even failure in the later part of the service life.

[0005]Third, due to the current passing through the liquid to be tested, electrolysis will occur between the electrolyte in the liquid to be tested and the electrodes, which will affect the composition of the liquid to be tested, resulting in The liquid to be tested is contaminated, and at the same time, the micro bubbles produced by its electrolysis will gather at each electrode end, making the resistance between each electrode end of the series resistance type or electrode type increase, and its effect is equivalent to the rise or fall of the water level. With the increase or decrease of bubble accumulation, the measurement result will gradually deviate from the correct liquid level value

[0006] 4. The traditional capacitive liquid level gauge measures the level of the liquid level by measuring the change of the capacitance between the two electrodes. The medium between the two electrodes is liquid and its For the above gas, only when the dielectric constants of the liquid to be measured and the gas are different and constant, can the capacitance value change with the liquid level be accurately measured, thus reflecting the change of the water level, but because the liquid to be measured and the gas above the liquid It is impossible for the dielectric constant to remain constant in the actual environment, and in most cases, due to the influence of the external environment such as temperature and humidity, the dielectric constant will have a large change. The water level does not change, and the capacitance value will also change with the change of the dielectric constant, so that the measured capacitance value cannot accurately reflect the actual water level.

[0007] 5. At the same time, the traditional capacitive liquid level sensing system cannot adapt to a variety of liquids to be tested. It is necessary to adjust the parameters of the sensor for each liquid to be tested. This is because the dielectric constant of the liquid generally increases with the temperature. , the time and the location are different. For different liquids to be tested, the sensor parameters also need to be manually adjusted accordingly. When the constant changes, the measured capacitance will change, which will cause errors in the measurement results, and cannot adapt to the measurement of liquids with constant dielectric constant and temperature.

[0008] 6. The traditional capacitive liquid level sensing system requires the container containing the liquid to be a conductive material such as a metal conductor, and it is necessary to connect one pole of the capacitor to the metal conductor of the outer cylinder wall of the liquid container, so the installation is inconvenient and needs to be filled. The wall of the container where the liquid is placed is made of conductive material

[0009] 7. The heating and antifreeze of the electric heating belt consumes a lot of energy, is not environmentally friendly, and is prone to fire

[0010] 8. The principle of pipe emptying makes it inconvenient for users to operate and wastes water resources. The reliability of the emptying valve in the outdoor low temperature environment is also relatively low

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