Tiankang Dual Flange Differential Pressure Level Transmitter

Anhui Tiankang Dual Flange Differential Pressure Level Transmitter Overview

The Anhui Tiankang dual flange differential pressure level transmitter is a smart level measurement instrument based on differential pressure measurement. It consists of a differential pressure transmitter, two remote diaphragm seal flanges, and two capillaries.

In closed tanks or pressurized vessels, the pressure at the bottom of the tank includes both the liquid column pressure and the vapor space pressure above the liquid. The pressure at the upper connection reflects the vapor space pressure. By measuring the difference between these two pressures, the transmitter can calculate the liquid level while compensating for the pressure above the liquid.

This makes the product especially suitable for:

• closed tank level measurement
• pressurized vessel level measurement
• vacuum tank level measurement
• reactor liquid level measurement
• tower and column level measurement
• corrosive liquid level measurement
• high-temperature or low-temperature liquid level measurement
• crystallizing, viscous, or easy-to-block media

Compared with a single flange level transmitter, the dual flange structure is more suitable when the top pressure of the vessel changes or when vapor pressure compensation is required.

Dual Flange DP Level Transmitter Working Principle

The dual flange differential pressure level transmitter measures the liquid level by comparing the pressure from the lower and upper remote seal flanges.

Typical pressure relationship:

• High-pressure side: liquid column pressure + vapor space pressure
• Low-pressure side: vapor space pressure
• Measured differential pressure: liquid column pressure

In simple terms:

Liquid Level → Differential Pressure → Remote Diaphragm Seals → Capillaries → DP Transmitter → 4–20 mA / HART Output

Because both sides are connected to the same vessel, the vapor pressure above the liquid is cancelled out. The remaining differential pressure corresponds to the liquid level.

This is why dual flange DP level transmitters are commonly selected for closed tanks, pressure vessels, and vacuum vessels.

Key Features of Anhui Tiankang Dual Flange DP Level Transmitter

Two Remote Diaphragm Seal Flanges

The transmitter uses two diaphragm seal flanges connected to the high-pressure and low-pressure sides of the DP transmitter. The process medium contacts only the diaphragm surface, while pressure is transmitted through filling fluid inside the sealed capillary system.

This structure helps prevent the medium from entering impulse lines or the transmitter sensor.

Suitable for Closed and Pressurized Tanks

For closed tanks and pressurized vessels, vapor space pressure can affect ordinary level measurement. The dual flange DP level transmitter compensates for this pressure by measuring both the lower and upper pressure points.

It is suitable for:

• closed storage tanks
• pressure vessels
• vacuum vessels
• reactors
• separators
• distillation columns
• evaporation systems
• chemical process tanks

Remote Seal Structure for Difficult Media

The remote diaphragm seal structure is suitable for media that may cause problems in traditional impulse line installation, such as:

• corrosive liquids
• viscous fluids
• crystallizing liquids
• dirty or slurry-like liquids
• high-temperature liquids
• low-temperature liquids
• toxic or hazardous media
• media that may block impulse tubes

Multiple Diaphragm Material Options

The diaphragm material should be selected according to process medium compatibility.

For strong acid, alkali, solvent, slurry, or special chemical media, material selection should be confirmed according to medium concentration, temperature, and corrosion behavior.

Filling Fluid Selection

The filling fluid inside the remote seal and capillary system transfers pressure from the diaphragm to the transmitter sensor.

Common filling fluid options include:

• silicone oil for general service
• high-temperature silicone oil
• low-temperature filling fluid
• fluorinated oil for oxygen or special applications
• special filling fluid for vacuum or high-temperature conditions

Filling fluid selection is critical because it affects response time, temperature performance, accuracy, and long-term stability.

Capillary Length Options

The capillary allows the transmitter body to be installed away from the process flange. This is useful when the vessel wall is hot, insulated, vibrating, or difficult to access.

When selecting capillary length, pay attention to:

• installation distance
• ambient temperature difference
• response time requirement
• height difference between two seals
• whether both capillaries should have equal length

For dual flange level measurement, capillary length and installation symmetry are important for stable measurement.

Flushing Ring Option

For viscous, crystallizing, or dirty media, a flushing ring can be installed between the tank flange and remote seal flange. It provides ports for flushing, cleaning, draining, or venting.

Typical structure:

Tank Flange → Gasket → Flushing Ring → Gasket → Remote Diaphragm Seal

This is useful for media that may deposit or crystallize around the diaphragm.

Technical Specifications for Dual Flange Differential Pressure Level Transmitter Selection

Industrial Applications of Anhui Tiankang Dual Flange DP Level Transmitter

Closed Tank Level Measurement

The dual flange DP level transmitter is suitable for closed tanks where vapor space pressure exists above the liquid. It measures both the lower and upper pressure points and cancels the top pressure influence.

Pressurized Vessel Level Measurement

For pressure vessels, separators, and reactors, tank top pressure may change during operation. The dual flange structure provides more reliable level measurement than a single flange level transmitter.

Vacuum Vessel Level Measurement

In vacuum vessels, the gas pressure above the liquid is lower than atmospheric pressure and may change during operation. A dual flange DP level transmitter can compensate for this condition.

Corrosive Chemical Liquid Level

With suitable diaphragm and flange materials, the transmitter can be used for acids, alkalis, solvents, and other corrosive process liquids.

Viscous or Crystallizing Media

The diaphragm seal prevents the process medium from entering impulse lines. This is useful for viscous liquids, crystallizing liquids, sticky media, and dirty fluids.

High-Temperature or Low-Temperature Level Measurement

Remote diaphragm seals and capillaries allow the transmitter body to be installed away from the process connection, helping protect electronics from extreme temperatures.

Tower, Reactor, and Separator Level Control

The product is commonly used in chemical and petrochemical towers, reactors, separators, evaporation systems, and process vessels where stable level control is required.

How to Select an Anhui Tiankang Dual Flange Differential Pressure Level Transmitter

When selecting a dual flange differential pressure level transmitter, confirm the following information:

1. Tank type
   Confirm whether the tank is closed, pressurized, vacuum, insulated, or open.
2. Liquid medium
   Confirm medium name, density, viscosity, corrosion, crystallization tendency, solid content, and toxicity.
3. Level range
   Confirm tank height, normal level, minimum level, maximum level, and required measurement span.
4. Process pressure
   Confirm normal pressure and maximum pressure inside the vessel.
5. Process temperature
   Confirm normal and maximum liquid temperature. Temperature affects diaphragm seal, filling fluid, and capillary selection.
6. Flange size and standard
   Confirm upper and lower flange sizes, pressure rating, sealing face, and standards such as ASME, EN, DIN, JIS, GB, or HG.
7. Diaphragm material
   Select 316L, Hastelloy C-276, tantalum, Monel, gold-plated, PTFE-coated, or other materials according to medium compatibility.
8. Capillary length
   Confirm capillary length and whether both sides should use equal length. Also check installation height difference and ambient temperature exposure.
9. Filling fluid
   Select suitable filling fluid according to temperature, vacuum condition, response time, and medium safety requirements.
10. Flushing ring requirement
    For crystallizing, viscous, dirty, or sticky media, confirm whether flushing rings are required on one or both flanges.
11. Output and display
    Confirm whether the transmitter requires 4–20 mA, HART communication, LCD display, or other communication options.
12. Installation accessories
    Confirm mounting bracket, gaskets, bolts, mating flanges, cable glands, and protective capillary supports.

Dual Flange DP Level Transmitter vs Single Flange Level Transmitter

For closed tanks or vessels with changing top pressure, the dual flange type is usually more appropriate. For open tanks or atmospheric vessels, a single flange level transmitter may be enough.

Dual Flange DP Level Transmitter vs Standard DP Transmitter with Impulse Lines

For clean liquid level applications, a standard DP transmitter with impulse lines may be economical. For corrosive, viscous, crystallizing, toxic, or high-temperature liquids, a dual flange DP level transmitter is often more reliable.

Installation Notes for Dual Flange Differential Pressure Level Transmitter

For stable measurement, the following points should be considered:

• Keep both capillaries protected from mechanical damage.
• Avoid sharp bending of the capillary.
• For outdoor installation, protect capillaries from direct sun exposure where possible.
• Keep the transmitter installed in a location convenient for reading and maintenance.
• Confirm whether both capillaries need equal length to reduce temperature influence.
• Install flushing rings if the medium is crystallizing, viscous, or easy to deposit.
• Confirm gasket material compatibility with the process medium.
• Avoid large temperature differences between the two capillaries where possible.
• Confirm correct high-pressure and low-pressure side connection.
• Recheck zero point after installation.

Accessories for Anhui Tiankang Dual Flange DP Level Transmitter

Common accessories include:

• Remote diaphragm seals
• Capillaries
• Flushing rings
• Mating flanges
• PTFE gaskets
• Spiral wound gaskets
• Mounting brackets
• Explosion-proof cable glands
• Capillary protection tubes
• Bolts and nuts
• HART handheld communicator

Typical installation:

Lower Tank Flange → Gasket → Remote Diaphragm Seal → Capillary → DP Transmitter

Upper Tank Flange → Gasket → Remote Diaphragm Seal → Capillary → DP Transmitter

If flushing rings are required:

Tank Flange → Gasket → Flushing Ring → Gasket → Remote Diaphragm Seal

Anhui Tiankang Dual Flange Differential Pressure Level Transmitter Supplier Support from SIYelectric

SIYelectric supplies Anhui Tiankang dual flange differential pressure level transmitters for chemical tanks, reactors, pressure vessels, vacuum vessels, separators, towers, and industrial level measurement projects. We can help check model codes, confirm flange standards, select diaphragm materials, confirm filling fluid, match capillary length, and prepare quotations based on actual site conditions.

For accurate quotation, please provide:

• tank type: closed tank, pressure vessel, vacuum vessel, reactor, separator, or tower
• liquid medium and density
• level measuring range
• normal and maximum process pressure
• normal and maximum process temperature
• upper and lower flange size, pressure rating, and standard
• diaphragm material requirement
• capillary length requirement
• filling fluid requirement
• flushing ring requirement
• output signal and display requirement
• electrical connection and explosion-proof requirement
• required accessories or documents

SIYelectric can also support related accessories such as flushing rings, mating flanges, PTFE gaskets, spiral wound gaskets, mounting brackets, capillary protection parts, explosion-proof cable glands, and HART communicators.

Available documents may include technical datasheet, certificate of conformity, inspection report, packing list, and commercial invoice, depending on order and project requirements.