Dual flange level transmitter

1. Products

The dual-flange level transmitter is a sealed container level measuring instrument designed based on the principle of differential pressure measurement. Through two sets of isolation diaphragms + capillary tube remote transmission structure, dielectric pressure is transmitted to the sensor core, allowing direct measurement of liquid level, boundary, and density without the need for pressure guide tubes. It is especially suitable for high-temperature, low-temperature, corrosive, viscous, easily crystallized, and easily solidified media, as well as sealed pressurized tanks, vacuum tanks, and reactors where direct pressure extraction is not possible, enabling stable, precise, and long-lasting automated liquid level monitoring.

2. Product Overview

This series of dual-flange liquid level transmitters uses high-precision monocrystalline silicon/diffusion silicon differential pressure sensors, paired with a fully sealed dual-flange isolation diaphragm system and high-temperature resistant capillary tubes, enabling stable measurement of liquid levels and interfaces of liquids, slurries, and corrosive media under extreme operating conditions. The product supports various flange specifications, anti-corrosion materials, diaphragm processes, and capillary lengths, offering advantages such as anti-crystallization, anti-clogging, resistance to high and low temperatures, and strong corrosion resistance. Outputs 4-20mA+HART standard signals, can be seamlessly integrated into PLC/DCS systems, and is widely used in automated level control of sealed containers in industries such as chemical, petrochemical, pharmaceutical, new energy, metallurgy, and water treatment.

3. Core Performance Parameters

・Measurement range: 0~1kPa ~ 0~10MPa (customizable according to tank height)

・Output signal: 4-20mA + HART / optional RS485-Modbus

・Accuracy grades: ± 0.075% FS, ± 0.1% FS, ± 0.2% FS

・Long-term stability: ≤±0.1% FS/year

・Power supply voltage: Standard DC24V

・Medium temperature: -40°C~+300°C (high-temperature models customizable)

・Ambient temperature: -40°C~+85°C

・Protection rating: IP67

・Explosion-proof rating: Ex d IIC T5

・Liquid contact diaphragm: 316L, Hastelloy C-276, tantalum, Monel, PTFE coating

・Flange Standards: GB/DIN/ANSI/JIS (DN25/DN50/DN80/DN100)

・Capillary tube length: 1m~10m Standard stock, customizable length

・On-site display: LCD (liquid level / percentage / current)

4. Working Principle

The dual-flange level transmitter operates based on the principle of static pressure differential pressure: the high-pressure flange diaphragm is installed at the lower part of the tank body, while the low-pressure flange diaphragm is installed at the gas phase of the tank. Two sets of diaphragms connect the transmitter body via liquid-filled sealed capillary tubes, and the medium pressure is transmitted to the differential pressure sensor via the isolation liquid. The internal circuit converts the differential voltage signal into a standard current of 4-20mA, with the output proportional to the liquid level height. With no pressure guide tubes, no contact with media, and fully sealed isolation, it can completely solve problems such as blockage, leakage, and corrosion caused by high temperature, corrosion, viscosity, and crystalline media.

5. Core Product Advantages

1. Dual flanges + capillary tube remote transmission; no pressure guide tubes to prevent clogging or leakage

Adopts a fully sealed remote transmission structure, eliminating the need for pressure extraction pipes, valves, or condensation tanks, completely eliminating issues such as blockage, crystallization, freeze blockage, leakage, and thermal tracing maintenance. Measurement of viscous media, slurry, asphalt, resin, and gels is more stable.

2. Ultra-strong anti-corrosion diaphragm, durable with strong acids and alkalis

Optional 316L, Hastelloy alloy, tantalum, Monel, PTFE laminated films, resistant to strong acids, strong alkalis, organic solvents, salts, and oxidizers, greatly extending lifespan under harsh chemical conditions.

3. Wide temperature adaptability: stable at both high and low temperatures

Capillary tube fillings are made of high-temperature/low-temperature resistant silicone oil or fluorine oil, compatible with media ranging from -40°C low temperature to +300°C high temperature, with minimal temperature drift and no degradation in measurement accuracy.

4. Specially designed for sealed tanks / vacuum tanks, with more precise measurement

Dual-side pressure intake at high and low pressure automatically offsets tank pressure effects. Pressure tanks, negative pressure tanks, reactors, and distillation tower liquid level measurements are precise and reliable, unaffected by pressure fluctuations inside the tank.

5. Fully sealed vibration-resistant structure: durable for industrial sites

Integrated welded sealing, vibration-resistant, impact-resistant, and anti-interference, IP67 protection, long-term stable operation in outdoor, tank areas, and explosion-proof zones, extremely low failure rate, and long maintenance-free period.

6. Intelligent HART communication: simple and convenient debugging

Supports remote zero point, range migration, temperature compensation, and self-diagnosis. Parameter settings can be set without opening the lid, making installation and debugging more efficient. Compatible with various industrial control systems, with zero barrier to replacement and upgrades.

7. Flexible installation to accommodate various complex tanks

Capillary tubes can be bent and extended, suitable for high-swelling tanks, deep-buried tanks, insulated tanks, thick-walled kettles, and special-shaped equipment. The installation position is not restricted, making installation more convenient.

6. Applicable industries and scenarios

・Chemical / Petrochemical: reactors, distillation towers, high-pressure storage tanks, acid-alkali tanks

・New energy: lithium battery slurry, electrolyte, chemical raw material tanks

・Pharmaceuticals / Food: sterile tanks, injection water tanks, syrup tanks, fermentation tanks

・Asphalt / Resin / Glue: High-temperature, viscous, and easily crystallized media

・Metallurgy / Papermaking: black liquor, white liquor, slurry, slurry liquid level

・Oil depots / storage: sealed tanks for gasoline, diesel, and chemical solvents

・Vacuum equipment: vacuum dryers, vacuum tanks, negative pressure tanks

7. Key Selection Parameters

To ensure accurate selection, please provide the following information:

1. Medium name, corrosiveness, viscosity, and whether it crystallizes or solidifies
2. Operating temperature, working pressure, and whether there is negative pressure
3. Tank types: Sealed tank / pressurized tank / vacuum tank
4. Measurement range (distance between high and low flanges)
5. Capillary length requirements
6. Flange specifications, materials, and anti-corrosion requirements
7. Whether explosion-proof and on-site display
8. Special requirements: high temperature, hygienic grade, negative pressure resistant, anti-clogging washing

8. Key points for installation and maintenance

・High and low pressure flanges must be installed separately in the liquid and gas phase positions

・Capillaries should avoid heavy pressure, bending, and sharp scratches ・Do not tap the diaphragm before installation to prevent damage

・High-temperature operation requires sufficient capillary cooling space ・Flushing ring structure is available for measuring easily crystallizing media

・Strictly follow explosion-proof standards for wiring and grounding in explosion-proof environments