UHGG-31A-G Inductive Float Sensor

UHGG-31A-G inductive float sensor is mainly suitable for automatic level control and detection in various boilers with a capacity of 0.5-35t/h and pressure ≤2.5MPa. It is also suitable for level detection in other low-pressure and open containers. When used in conjunction with our secondary instruments (SZD-A, SZD-S-2, SZD-S-4, UHG-311-G, UHG-311-BP, UHG-311-CT, AB2000, AB3000 intelligent controller series instruments), it can realize water level display, high and low limit alarms, and automatic water level adjustment to ensure the safe operation of the boiler.

Main Technologies:

1. Applicable media: Non-corrosive liquids with a specific gravity ≥ 0.8

2. Working pressure: ≤1.6MPa, 2.5MPa or ≤4.0MPa

3. Operating temperature: ≤250°C

4. Relative humidity: ≤85%

5. Detection range: +50 -75

6. Nominal diameter: 25mm

7. Key Performance Specifications:

Model/Specification L (Flange Center Distance) Unit: mm Working Pressure Cylinder Diameter Float Diameter

UHGG-31A-G 300, 350, 400, 440 ≤2.5MPa Ф89 Ф75

High-pressure type UHGG-31A-G 300, 350, 400, 440 ≤4.0MPa Ф89 Ф75

Working Principle:

The steam-water pipe flange on the sensor cylinder is connected to the boiler drum, linking the water levels in the boiler drum and the cylinder. When the water level in the boiler drum changes, the water level in the cylinder changes accordingly. The float in the cylinder moves according to the water level; when the water level rises, the float rises; when the water level falls, the float falls, causing the silicon rod connected to the float to move within the inductor coil. This causes a corresponding change in the inductance mH across the inductor coil. This change in inductance is sent to the secondary instrument, which receives this inductance change signal and converts it into an indicator and signal corresponding to the water level. This triggers the automatic control of the water pump’s start and stop. In case of a malfunction in the water supply system, indicator lights will show whether the water is low or high, and a buzzer alarm and a light alarm will sound simultaneously.

Installation and Maintenance:

1. Please refer to Figure (1) for sensor installation.

2. Two Dg25 shut-off valves are installed between the sensor and the controlled container for debugging and maintenance. During normal operation, both valves must be fully open.

3. The sensor must be installed perpendicular to the plane of the controlled container, and the tilt angle must not exceed 2°.

4. The sensor must be installed in a drain pipe and drain valve.

5. Connect the two ends of the terminal block to the inductor coil, and connect the other two ends to the liquid level signal input terminal of the secondary instrument.

6. The sensor should be drained frequently (at least once per shift). The stainless steel float inside the sensor should be checked regularly, and the surface of the float should be cleaned every six months.

7. When the liquid level signal is abnormal, the following methods should be used for inspection:

a. Disconnect any terminal wire from the sensor housing terminal block to prevent it from forming a circuit with the secondary instrument.

b. Use a multimeter set to the R×10 range to check the two ends of the inductor coil. When normal, its resistance is about 200 ohms.

c. Disassemble the sensor and check if the float is leaking.

8. Replace the inductor promptly if the inductor coil is open (internal circuit is not continuous) or if the float is leaking water.