Improvement and Function Expansion of Float Level Gauge

Improvement and Function Expansion of Float Level Gauge

    The float level gauge is mainly composed of three parts: magnetic float, sensor and transmitter. When the magnetic float floats up and down along the guide rod as the liquid level changes, the magnetic steel in the float attracts the reed switch at the corresponding position in the sensor to change the total resistance (or voltage) of the sensor, and then the transmitter The device converts the changed resistance (or voltage) signal into a 4-20mA current signal output, which can display the percentage of the liquid level, 4-20mA current and the value of the liquid level on the spot, and the remote transmission supply to the control room can realize the automatic detection of the liquid level , Control and record. The color quartz tube level gauge is suitable for the measurement of the medium level in various atmospheric and pressure vessels, especially for the level measurement of underground storage tanks and storage tanks.

    Generally, we produce and apply these products. We encountered some other problems at the scene.

1. The medium temperature is between 130-150 degrees

    Here we need to consider the following issues; the issue of magnetic steel, the issue of resistance temperature drift, and the issue of the operating temperature of the reed switch.

    The use of magnets at high temperatures can now be resolved, we will not elaborate here. The temperature drift problem of the resistor can be solved as long as the metal film resistor with the same batch number is used. The only operating temperature range of reed switches is currently between -25 and 125 degrees for foreign brand reed switches. Many steam solenoid valve companies use some domestically produced reed switches in order to reduce costs. Their operating temperature is still low. To be low.

    We have adopted two measures on this issue: 1. Choose higher quality reed switches and use temperature up to 150 degrees. 2. Use jacketed guide rods to draw a vacuum between the two guide rods to produce better heat insulation. , To ensure the normal use of the float level gauge and convenient maintenance.

Second, increase the switch output in addition to the output 4-20mA

     For the sake of safety, users increase the reliability. In the past, the 4-20mA input was accepted in the secondary meter and the upper and lower limit output was set on the secondary meter, so that the level meter would not be able to do so if there is a problem in the signal transmission process. Normal use.

    We increased the output of the switch signal during the production of the instrument. At the same time, the switch signal has a self-holding function. The two outputs are isolated and have no influence on each other.

3. Self-correction function

    Normally the output of the level gauge is always adjusted when the ball is hit to the bottom to output 4mA, and to the top to output 20mA, but it is not convenient to take it out for calibration in some toxic and hazardous materials storage tanks. We have designed a self-correcting switch. This switch has two gears: working status/correction status. Working status The level gauge works normally. If the tank is empty, we can calibrate the zero level. At this time, the output is 4mA. When we turn the switch to the calibration status, the level gauge should output 20mA. If drift occurs, it can be adjusted at any time. Normally, the normal use of the level gauge can always be guaranteed.

Fourth, increase the digital output with hart

    This kind of expansion is more convenient. The electric actuator replaces the usual resistance/current XB conversion module with an intelligent XBH conversion module with hart function. Under this kind of conversion, it should be noted that the size of the resistance has a certain influence, we use between zero and several thousand ohms.

     The above are just some fragments that we encountered during the production process. We have improved the performance of the float level gauge and expanded its functions.

This article is original by the manufacturer of the magnetic turning column level gauge, please indicate http://www.sungofluid.com/