Tank level sensor

Types of tank level sensors

Tank level sensors are essential to help effectively monitor liquid or material storage in various tanks. These sensors provide crucial data for numerous industries, whether they involve water treatment, oil and gas, or chemicals. Therefore, it is important to have a good understanding of these types as they differ in measurement techniques and applications.

Ultrasonic Level Sensors

Ultrasonic level sensors operate by emitting high-frequency sound waves to measure the level of liquid or materials in a tank or vessel. The sound waves reflect back after hitting the substance's surface, and the sensor calculates the time taken for the waves to return. This time is then converted into an appropriate level measurement.

These sensors are non-contact, making them suitable for a wide range of industries. They are prominently used in water and wastewater treatment, chemical storage, and mining due to their accuracy and reliability. However, factors like foam, vapors, and turbulence occasionally impact their measurements, requiring compensation for these factors.

Capacitive Level Sensors

Capacitive level sensors work by measuring the change in capacitance which occurs when the level of the material or liquid in the tank changes. Each dielectric material offers varying capacitance, so when the tank is empty, the tank is made up of dielectric material that offers capacitance.

However, when the tank is filled with liquid or material, the capacitance changes as the dielectric constant of the substance within the tank differs from that of the surrounding dielectric material. These sensors are highly useful in measuring levels of liquids and solids in various industries like food and beverages, petrochemicals, and pharmaceuticals as well as other processing industries.

Pneumatic Level Sensors

Pneumatic level sensors use air pressure to measure the level of liquid or material in a tank. These sensors work by a pressure-generating pipe that extends down into the tank. As the level of liquid rises in the tank, the pressure of the liquid also rises, causing the pneumatic sensor pipe to provide more resistance against the air pressure.

This change in pressure is then converted into a corresponding level measurement. These sensors are commonly used in industries where electrical sensors cannot match up, and efficient performance is mandatory. They are also suitable for measuring liquids with volatile organic compounds (VOCs) in hazardous environments.

Radar Level Sensors

Radar level sensors, like ultrasonic level sensors, are suitable to be used for non-contact level measurement. These sensors operate by sending microwave signals to the surface of the material or liquid being measured. The signal reflects back to the sensor after it strikes the substance's surface. Besides, the time taken for the signal to return is what is used to measure the level.

The main types of radar level sensors include guided waves, which are sent out without a guide. These sensors are extremely accurate and work well even in harsh environments. In addition, they also work well in tanks with agitation, vapors, and foam. They are also used in tank level monitoring for chemical processing and water treatment.

Commercial uses of tank level sensors

Water and Wastewater Treatment

Tank level sensors are generally used in water and wastewater treatment for their seamless management of water storage, treatment tanks, and chemical dosing reservoirs. They make it convenient to monitor tank levels in real time, enabling efficient pumping, treatment, and chemical dosing operations to be carried out.

This helps prevent overflow or dry running of pumps, which can cause equipment damage. Also, maintaining optimal water levels helps minimize energy consumption and operational costs, all while ensuring regulatory compliance and reliable service delivery to the end users.

Oil and Gas Industry

The level sensors in this industry are durable and able to survive extreme conditions, which makes them suitable for their not-so-easy-to-work environment. They are used by the professionals to monitor the levels of oil and gas in storage tanks, pipelines, and vessels. In fact, the sensors provide accurate measurements, facilitating inventory management and safety.

Additionally, they come in handy in preventing spills, overflows, and other hazardous situations. Since this sensor is so reliable, it reduces the need for manual checks, which offers more efficiency and accuracy in operations while improving safety in the monitoring of hazardous substances.

Chemical Processing

Tank level sensors are widely used in the chemical processing industry to monitor the levels of feedstock, finished chemicals, and other liquids in storage tanks and reactors. This enables manufacturers to maintain optimal operating conditions, prevent equipment damage, and ensure safety. In fact, they help prevent dangerous situations like overflow or tank collapse, which is good for the user's experience.

The sensors offer accuracy, reliability, and real-time monitoring, which enhances process efficiency, reduces downtime, and provides valuable data for inventory management and regulatory compliance. The sensors are also strong enough to handle different kinds of chemicals.

Food and Beverage Industry

Users in the food and beverage industry use capacitive and ultrasonic level sensors to monitor liquid levels in various storage and processing tanks. These sensors help to maintain consistent product quality by ensuring proper inventory management. They also prevent overflows and equipment damage while providing real-time data on tank levels.

This reduces the need for manual monitoring, improving operational efficiency. Additionally, they support compliance with stringent industry regulations by providing accurate and reliable measurements in hygienic sensor designs.

Pharmaceuticals

Here, level sensors are essential for monitoring the levels of raw materials, solvents, and final products in storage tanks and reactors. These sensors are critical for maintaining accuracy in this sensitive production process. In fact, they ensure safety, prevent overflow and equipment damage, and provide real-time monitoring to enable effective control of drug manufacturing processes.

These sensors also support compliance with strict regulatory standards, which are essential for the quality assurance of pharmaceuticals. The level sensors offer reliable performance in this industry.

Tank level sensor specifications

Performance specifications

These are the specifications that determine the working capability of tank level sensor:

• Measurement range: The distance that the sensor measures is from the reference point to the material surface.
• Accuracy: This is the nearness to the actual value. There is generally an error associated with it.
• Resolution: The smallest incremental change the sensor can detect.
• Response times: The time taken to give output after a change happens in the tank level.
• Signal interception: This is the capability of the sensor to measure the reflected signal.
• Environmental rejection: This is the strength of the sensor against environmental disturbances like electromagnetic interferences.

Installation specifications

These specifications are important because they affect efficiency and convenience:

• Mounting position: The body and the head of the sensors can be mounted in different angles.
• Mechanical protection: Sensors are protected by enclosures in case of hazardous environment. This protection is rated by IP and NEMA standards.
• Wiring connection: This connects the sensor to the control system. It can be classified as explosion proof.
• Commissioning: Some sensors come with auto configuration that eases the adjustments and settings. Also, some come with defaults that need changed before beginning the operations.

Operating specifications

These specifications involve the specifications for the sensor during normal operations:

• Supply voltage: A certain power source is needed by the sensor to operate. The type of power source a sensor needs is classified by voltage or DC and AC type.
• Output type: Certain sensors have voltage outputs. In contrast, others have current or frequency outputs.
• Self-test: These are the operations the sensors do on themselves periodically to check for faults.
• Failure behavior: This is how the sensor acts upon failures. Some sensors for example may fall into safe mode.

Technical specifications

These details are the specifications that involve the details of the sensors:

• Material: The sensors are made of various materials like plastic, metal, and ceramics. These materials are chosen based on how they will react to the process.
• Maintenance: Most devices require constant maintenance to clean and replace. But some devices like radar sensors are described as maintenance-free.
• Certification: Some sensors go through testing to comply with various standards and are certified by organizations.

How to choose tank level sensors

The first step in selecting a tank level sensor is to understand the liquid or material to be measured. Information on the temperature, pressure, and density of the substance helps in deciding the sensor technology. Measuring the dielectric constant of the liquid or material will also help. The sensors work well with high dielectric constants. If the users have a low dielectric constant, then go for a capacitive sensor.

Next, consider the tank conditions. Factors like tank shape, size, and material will contribute to the overall measurement. For example, if the tank is agitated or has irregular shapes, then go for a non-contact sensor like ultrasonic or radar. Then take into consideration the environmental conditions. Ambient temperature, pressure, and humidity will affect the sensor performance.

Also, think about the installation conditions. What are the available mounting positions? What are the available power sources? Finally, think about the required measurement accuracy and resolution. If real-time monitoring is needed, then select a sensor with a short response time.

Q&A

Q1: Are tank level sensors safe to monitor corrosive liquids?

A1: Yes, sensors are designed to operate effectively and measure corrosive liquids in corrosion-resistant materials such as PTFE.

Q2: What are the differences between ultrasonic and radar level sensors?

A2: While both are non-contact level sensors, radar level sensors offer better performance in extreme conditions than turbulence and vapors. On the other hand, ultrasonic sensors are more affordable.

Q3: Which tank level sensor is suitable for a food and beverage application?

A3: For food and beverages, users should go for a capacitive level sensor.

Q4: How to maintain a level sensor?

A4: Regularly inspect the sensors and clean them, if applicable, to remove any buildup. Check the calibration and replace worn parts as needed.

Q5: Can tank level sensors be used for inventory management?

A5: Yes, they provide precise measurements of current tank contents, helping users track the amount of materials stored in tanks.