What Are The Different Types of Submersible Level Transmitters?

Introduction

Accurate liquid level measurement is crucial for many industries. Submersible level transmitters offer a reliable solution, directly measuring liquid levels by sitting in the fluid. These devices are vital in water treatment, chemical processing, and more. In this post, you'll learn about their types, features, and benefits, ensuring optimal performance in demanding environments.

 

Understanding Submersible Level Transmitters

Definition and Functionality

Submersible level transmitters are devices designed to measure liquid levels by being placed directly in the fluid. They sit at the bottom of tanks, wells, or reservoirs, detecting the height of the liquid above them. These transmitters convert the pressure exerted by the liquid column into an electrical signal, typically a 4-20 mA output, which can be sent to monitoring or control systems. Because they are submerged, they provide direct and continuous measurement of liquid levels, making them highly reliable for real-time monitoring.

Hydrostatic Pressure Principle

The core principle behind submersible level transmitters is hydrostatic pressure. This principle states that the pressure at a certain depth in a liquid is proportional to the height of the liquid column above that point. The formula used is:

P = h × ρ × g

Where:

● P is the pressure measured by the sensor

● h is the height of the liquid column

● ρ is the liquid's density

● g is the acceleration due to gravity

As the liquid level rises, the pressure on the sensor increases proportionally. The transmitter senses this pressure and converts it into an electrical signal that reflects the liquid level. This method works well even in turbulent or foamy liquids because the sensor measures pressure directly, not the surface.

Comparison with Other Level Measurement Technologies

Several technologies exist for liquid level measurement, each with pros and cons:

● Hydrostatic (Submersible) Sensors:Pros: Direct contact, accurate in foam or vapor, resistant to harsh chemicals

○ Cons: Must be submerged, sensitive to liquid density changes

● Ultrasonic Sensors:Pros: Non-contact, easy to install

○ Cons: Affected by foam, vapor, turbulence, and dust

● Radar Sensors (including Guided Wave Radar):Pros: Non-contact, highly accurate, unaffected by vapor or foam

○ Cons: Higher cost, more complex installation

● Float Switches:Pros: Simple, cost-effective for basic on/off level detection

○ Cons: Limited accuracy, not continuous measurement

Submersible level transmitters excel in applications requiring continuous, accurate, and reliable measurement, especially where foam, vapor, or chemical corrosion may interfere with other sensor types. Their robust design and direct measurement capability make them ideal for challenging industrial environments.

Note: When selecting submersible level transmitters, consider liquid density and temperature variations, as these factors can affect hydrostatic pressure readings and overall accuracy.

 

Types of Submersible Level Transmitters

Submersible level transmitters come in various models, each tailored to specific industrial needs and environments. Here, we explore five popular types: 100 Series, 200C Series, 300S Series, TankPro Series, and LP 100 Junction Box.

100 Series

The 100 Series is designed for industries requiring precise liquid level measurement in harsh conditions. It features a ceramic sensing diaphragm and materials like PVC, PP, PVDF, and PTFE Teflon® for excellent chemical resistance. Its integral molded weight keeps the sensor anchored at the bottom, ensuring accurate readings regardless of turbulence or foam. The transmitter offers 4-20mA output and optional RS485 communication. This series suits chemical tanks, water treatment, and wastewater applications.

Key Features:

● High accuracy (±0.5% full scale)

● Corrosion-resistant materials

● Non-clogging design with no moving parts

● Easy installation with integral molded weight

● Compatible with SCADA systems

200C Series

The 200C Series targets tough industrial environments, including aggressive chemical applications. It uses a ceramic diaphragm with an anti-clogging design, enhancing performance in viscous or sludge-filled liquids. The construction materials are similar to the 100 Series but emphasize durability and chemical resistance. Its NEMA 4X epoxy-coated housing protects against harsh external factors. Like the 100 Series, it provides a 4-20mA output and is designed for continuous, reliable level measurement.

Key Features:

● Advanced anti-clogging ceramic diaphragm

● Superior chemical resistance with Kalrez® O-rings

● Integral molded weight for stable placement

● High-resolution output for precise control

● Heavy-duty design for industrial use

300S Series

The 300S Series is built for high-pressure and deep tank applications. It features a 316 stainless steel sensing diaphragm, which withstands pressures up to 20 bar. This makes it ideal for oil, gas, and chemical processing industries where durability under extreme conditions is critical. The sensor maintains accuracy (±0.5%) and reliability in corrosive environments. The 300S Series also includes a Teflon® jacketed cable and Kalrez® O-ring seals for enhanced chemical resistance.

Key Features:

● Stainless steel or PTFE diaphragm options

● High-pressure tolerance (up to 20 bar)

● Multi-range calibration available

● Robust construction for long-term reliability

● 4-20mA output with no programming required

TankPro Series

TankPro transmitters combine compact design with modularity, making installation straightforward. They are suitable for both corrosive and non-corrosive liquids, with materials like PVC, PP, PVDF, and PTFE. The sensor includes a ceramic diaphragm and integral molded weight to ensure stable positioning. TankPro supports real-time digital output, enabling continuous level monitoring. Its NEMA 4X epoxy-coated housing and 2″ NPT connection make it perfect for food processing, pharmaceuticals, and high-temperature applications.

Key Features:

● Compact, modular design for easy installation

● High-temperature resistance

● Digital output for real-time monitoring

● Integral molded weight for accuracy

● Suitable for sensitive industries like food and pharma

LP 100 Junction Box

The LP 100 Junction Box is an accessory designed to simplify wiring and connections for submersible sensors. It features an IP65-rated housing and multiple input/output compatibility. The box includes Vaporbloc® technology, which allows air entry but prevents moisture ingress, protecting sensor cables. Its lightweight, all-plastic NEMA 4X enclosure ensures durability in harsh environments. The LP 100 Junction Box enhances sensor longevity and supports seamless integration into process control systems.

Key Features:

● Simplifies sensor wiring and installation

● IP65 protection against dust and water

● Vaporbloc® technology for moisture control

● Compatible with LevelPro submersible sensors

● Lightweight, durable plastic enclosure

 

Key Features of Submersible Level Transmitters

Submersible level transmitters are engineered to provide reliable, accurate liquid level measurements in demanding environments. Their design focuses on durability, precision, and ease of use. Here are the key features that make these transmitters stand out:

Robust Construction

These transmitters are built to endure harsh conditions. They use high-quality materials like PVC, PP, PVDF, PTFE Teflon®, and 316 stainless steel. Such materials resist corrosion, chemical attack, and physical damage. The sensors often include Kalrez® or Viton O-ring seals to ensure tight waterproofing and chemical resistance. Their housing typically meets IP68 standards, allowing full submersion without compromising functionality.

High Accuracy

Accuracy is crucial for process control and safety. Most submersible transmitters offer accuracy around ±0.5% of full scale, with some models achieving even finer precision. This ensures operators get dependable data for liquid level monitoring, even in turbulent or foaming liquids. The ceramic or stainless steel diaphragms used in sensors provide stable, repeatable pressure readings.

Wide Range of Applications

These transmitters suit many liquids — from clean water to aggressive chemicals and sludge. Their chemical-resistant materials and robust design allow use in industries like water treatment, oil and gas, chemical processing, and food production. They handle diverse tank sizes and depths, from shallow reservoirs to deep wells.

Easy Installation

Designed for straightforward setup, submersible transmitters typically come with integral molded weights. This feature keeps the sensor positioned at the tank bottom, ensuring consistent readings. The cables are often Teflon® coated for chemical resistance and flexibility. Many models require no programming, simplifying integration with existing control systems.

Long Lifespan

Their durable construction and corrosion-resistant components extend operational life. These transmitters maintain performance over years, reducing replacement and maintenance costs. The absence of moving parts minimizes wear and failure points, contributing to longevity.

Reliable Performance

Submersible transmitters provide continuous, real-time level data unaffected by foam, vapor, or turbulence. Their hydrostatic pressure measurement principle ensures stable readings regardless of surface conditions. Additionally, they offer versatile output signals, like 4-20mA or RS485, compatible with most monitoring systems.

 

Benefits of Using Submersible Level Transmitters

Submersible level transmitters bring many advantages that make them a preferred choice in liquid level measurement across industries. Their design and technology offer distinct benefits that improve process control, safety, and operational efficiency.

Accurate Measurements

These transmitters provide highly precise readings by directly measuring hydrostatic pressure at the liquid's bottom. This direct contact eliminates errors common in non-contact sensors caused by foam, vapor, or turbulence. Accuracy typically reaches ±0.5% of full scale, ensuring reliable data for critical processes. This precision helps optimize chemical dosing, prevent overflows, and maintain consistent product quality.

Versatility

Submersible transmitters work well across various liquids—clean water, wastewater, chemicals, oils—and in different tank sizes and shapes. Their chemical-resistant materials like PVC, PVDF, PTFE, and stainless steel allow use in harsh, corrosive environments. This adaptability means one sensor type can serve many applications, reducing the need for multiple specialized devices.

Durability

Built from robust materials and sealed with high-grade O-rings such as Kalrez® or Viton, these transmitters withstand corrosion, abrasion, and extreme temperatures. Their IP68-rated housings protect against dust and water ingress. Without moving parts, they resist mechanical wear and clogging, ensuring long operational life even in sludge or viscous liquids.

Ease of Use

Installation is straightforward thanks to integral molded weights that keep the sensor stable at the tank bottom. The Teflon®-coated cables resist chemical attack and maintain flexibility. Most models require no programming, simplifying integration into existing control systems. This user-friendly design reduces installation time and maintenance efforts.

Cost-Effectiveness

Though initial costs may be higher than simple float switches, submersible transmitters offer a lower total cost of ownership. Their accuracy reduces waste and downtime, while durability cuts replacement frequency. Minimal maintenance further lowers operational expenses. Over time, these savings justify the investment in quality sensors.

Improved Safety

Accurate, continuous level data helps prevent dangerous overfills, dry runs, or chemical spills. Reliable measurement supports automated control systems that maintain safe operating limits. Chemical-resistant construction also protects personnel by reducing leak risks. These safety benefits are crucial in industries handling hazardous liquids.

 

Applications of Submersible Level Transmitters

Submersible level transmitters are versatile devices widely used across many industries. Their ability to provide accurate, continuous level measurements in harsh environments makes them essential for efficient process control and safety. Below are some key applications:

Water Treatment

In water treatment plants, maintaining precise water levels ensures smooth operation and regulatory compliance. Submersible level transmitters monitor water in tanks, reservoirs, and wells. They help control chemical dosing, prevent overflow, and optimize filtration processes. Their resistance to corrosion and fouling makes them ideal for this environment.

Wastewater Management

Wastewater treatment involves handling sludge and corrosive liquids. Submersible transmitters provide reliable level data in these challenging conditions. They monitor tanks, clarifiers, and lift stations to prevent spills and ensure proper processing. Their robust construction withstands abrasive and chemically aggressive fluids, reducing maintenance needs.

Chemical Processing

Chemical plants require precise level control for safe storage and reactions. Submersible level transmitters measure liquid levels in tanks containing acids, solvents, or other aggressive chemicals. Materials like PTFE and PVDF protect sensors from corrosion. Continuous monitoring helps avoid overfills, leaks, and unsafe conditions.

Food and Beverage Industry

Consistent liquid levels are vital in food and beverage production for quality and safety. These transmitters measure levels in storage tanks, mixing vessels, and process lines. Their food-grade compatible materials and hygienic designs meet industry standards. They also resist cleaning agents and temperature variations common in this sector.

Environmental Monitoring

Monitoring water levels in natural bodies like rivers, lakes, and reservoirs is crucial for environmental management. Submersible level transmitters provide accurate data for flood warning, irrigation control, and ecosystem studies. Their rugged design allows long-term deployment in outdoor, submerged conditions.

Oil and Gas Industry

In oil and gas, accurate level measurement ensures safe storage, transport, and processing of liquids. Submersible transmitters monitor tanks, pipelines, and wells. Their stainless steel construction and high-pressure tolerance withstand harsh environments. Reliable data supports operational efficiency and prevents hazardous incidents.

 

Why Submersible Level Transmitters are the Best Option

Submersible level transmitters offer several advantages that make them the preferred choice for many liquid level measurement applications. Their design and technology provide reliable, accurate, and durable solutions, especially in challenging environments.

Direct Measurement

Unlike non-contact sensors, submersible transmitters measure liquid levels by being placed directly in the fluid. This direct contact allows them to sense the hydrostatic pressure exerted by the liquid column above. Because of this, they provide continuous, real-time data rather than just point-level detection. This direct measurement approach eliminates errors caused by foam, vapor, or surface turbulence, ensuring precise and consistent readings even in difficult conditions.

Resistant to Environmental Factors

Submersible transmitters are built to withstand harsh environments. Their housings use corrosion-resistant materials such as PVC, PVDF, PTFE, and stainless steel. Sealing technologies like Kalrez® or Viton O-rings prevent moisture ingress and chemical attack. These sensors tolerate extreme temperatures, high pressures, and aggressive chemicals without degradation. They also resist fouling and clogging, which can impair other sensor types. This robust construction ensures reliable operation in industrial, wastewater, chemical, and oil and gas settings.

Minimal Maintenance

Because submersible transmitters have no moving parts, they require less maintenance than mechanical or float-based sensors. Their rugged materials resist corrosion and abrasion, reducing wear and tear. The integral molded weight keeps the sensor stable at the tank bottom, preventing damage from movement or turbulence. Additionally, their sealed design prevents moisture and contaminants from entering, extending service life. This durability translates into fewer replacements and less downtime, saving operational costs.

Wide Application Range

These transmitters suit a broad spectrum of liquids and tank types. They measure clean water, wastewater, oils, chemicals, and sludges. Their chemical-resistant materials allow use in aggressive media, while pressure ratings accommodate shallow tanks or deep wells. Submersible transmitters integrate easily with various control systems through standard outputs like 4-20mA or digital protocols. This versatility means one sensor type can serve multiple industries and process conditions, simplifying inventory and training.

Reliability

Consistency is key in level measurement. Submersible transmitters deliver stable, repeatable readings unaffected by surface conditions such as foam or vapor. Their hydrostatic principle is straightforward and proven, reducing the risk of signal drift or false alarms. Many models include self-diagnostics and temperature compensation for enhanced accuracy. This reliability supports better process control, safety, and regulatory compliance.

 

Conclusion

Submersible level transmitters directly measure liquid levels, offering accurate and continuous data even in challenging conditions. They excel in harsh environments due to their robust construction and minimal maintenance needs. Future trends in level measurement technologies may focus on enhancing integration and precision. Nanjing Hangjia Electronic Technology Co., Ltd. provides innovative solutions with unique benefits, ensuring reliable performance and value across industries. Their products stand out for durability and versatility, making them ideal for diverse applications.

 

FAQ

Q: What is a Submersible Level Transmitter?

A: A Submersible Level Transmitter is a device placed in liquids to measure levels by converting hydrostatic pressure into an electrical signal, providing real-time monitoring.

Q: How do Submersible Level Transmitters work?

A: They work by detecting hydrostatic pressure at the liquid's depth, converting it to an electrical signal that indicates the liquid level.

Q: Why choose a Submersible Level Transmitter over other sensors?

A: They offer continuous, accurate measurements unaffected by foam or vapor, ideal for harsh environments.

Q: What are the benefits of using a Submersible Level Transmitter?

A: Benefits include high accuracy, durability, versatility, minimal maintenance, and cost-effectiveness.

Q: How much do Submersible Level Transmitters cost?

A: Prices vary based on features and materials, but they offer long-term savings through durability and reduced maintenance.