In industrial liquid storage and process systems, accurate liquid level detection plays a critical role in ensuring stable operation, preventing tank overflow, protecting pumps from dry running, and automating production processes. To meet these requirements, the Magnetic Float Level Switch has become one of the most widely used liquid level sensing devices thanks to its simple operating principle, high reliability, and compatibility with a wide range of operating environments.

The Magnetic Float Level Switch is designed to monitor liquid levels through the movement of a permanent magnetic float along a guide stem, providing precise ON/OFF switching signals for pumps, solenoid valves, alarms, and automatic control systems. With multiple material options, various mounting configurations, and weatherproof or explosion-proof enclosure types, the product is suitable for numerous industrial liquid level control applications.

1. What is a Magnetic Float Level Switch?

A Magnetic Float Level Switch is a liquid level sensing device that detects liquid level by utilizing the movement of a float containing a permanent magnet inside a tank.

When the liquid level rises or falls, the float moves vertically along the guide stem. The magnetic field generated by the float actuates the reed switch installed inside the guide tube, causing the electrical contact to switch between the ON and OFF states.

The generated switching signal is used to:

• Start or stop pumps.
• Open or close solenoid valves.
• Activate high-level or low-level alarms.
• Transmit liquid level status to automatic control systems.
• Protect equipment from dry running or overflow.

Due to its simple structure, high durability, and stable operation, the Magnetic Float Level Switch is widely used in water treatment systems, chemical processing, petroleum, food processing, pharmaceutical manufacturing, HVAC systems, and numerous industrial applications.

2. Construction of the Magnetic Float Level Switch

The Magnetic Float Level Switch consists of the following main components:

Float

The float contains a built-in permanent magnet and moves according to changes in the liquid level.

Available float materials include:

• SUS304 stainless steel
• SUS316 stainless steel
• PVC
• PP
• PVDF

Different float sizes are available to meet various liquid density and application requirements.

Guide Stem

The guide stem houses one or more reed switches.

Available wetted materials include:

• SUS304
• SUS316
• PVC
• PP
• PVDF

Reed Switch

The reed switch is hermetically sealed inside the guide stem.

When activated by the magnetic field of the float, it generates an electrical ON/OFF contact output.

Connection Head

The connection head protects the electrical terminals and cable connections.

Multiple enclosure types are available, including:

• Weatherproof type
• Explosion-proof type
• Aluminum alloy enclosure
• Engineering plastic enclosure

3. Operating Principle

The operating principle of the Magnetic Float Level Switch is based on magnetic induction.

The sequence of operation is as follows:

• The liquid level rises.
• The float moves upward.
• The permanent magnet inside the float approaches the reed switch.
• The reed switch changes state.
• An ON or OFF electrical signal is generated.

When the liquid level decreases:

• The float moves downward.
• The reed switch returns to its original state.
• The electrical contact changes accordingly.

The switching output can be configured as:

• Normally Open (NO)
• Normally Closed (NC)
• SPST
• SPDT

Multiple switching points can also be provided according to customer requirements.

4. Product Specifications

Typical technical specifications include:

Wetted Materials

• SUS304
• SUS316
• PVC
• PP
• PVDF

Electrical Contact Types

• SPST
• SPDT

Maximum Switching Voltage

• Up to 250 VAC/DC

Maximum Switching Current

• Up to 2 A

Maximum Switching Capacity

• Up to 60 VA

Operating Temperature

Depending on the float material:

• Metal floats:
  -20°C to +130°C
• PVC floats:
  0°C to +70°C
• PP floats:
  0°C to +60°C
• PVDF floats:
  0°C to +120°C

Connection Sizes

• Threaded connections:
  1/2″, 3/4″, 1″, 1-1/2″, 2″, 3″
• Flanged connections:
  1-1/2″ to 4″

Protection Ratings

Available enclosure types include:

• IP66
• IP68
• Weatherproof
• Explosion-proof

5. Outstanding Features of the Magnetic Float Level Switch

The Magnetic Float Level Switch offers numerous advantages, including:

• Simple operating principle.
• High switching accuracy.
• Stable ON/OFF signal output.
• No external power supply required for sensing.
• Long service life.
• Easy installation and maintenance.
• Suitable for both clean liquids and chemical liquids.
• Multiple float materials available.
• Various enclosure options.
• Customizable multiple switching points.

6. Advantages of Using a Magnetic Float Level Switch

Installing a Magnetic Float Level Switch provides significant operational benefits:

• Prevents tank overflow.
• Protects pumps against dry running.
• Automates pump operation.
• Reduces operating costs.
• Improves process safety.
• Enhances production efficiency.
• Requires minimal maintenance.
• Performs reliably over long-term operation.

7. Practical Applications

The Magnetic Float Level Switch is widely used in:

• Water treatment systems.
• Wastewater treatment plants.
• Chemical storage tanks.
• Food and beverage processing plants.
• Pharmaceutical manufacturing facilities.
• Oil and gas industry.
• Petrochemical plants.
• Boiler feedwater systems.
• Cooling towers.
• HVAC systems.
• Industrial process tanks.
• Fire water tanks.
• Cooling water tanks.
• Diesel storage tanks.
• Lubricating oil tanks.

8. Installation and Maintenance Guidelines

Installation

For proper installation:

• Select the appropriate installation location.
• Ensure sufficient float travel distance.
• Verify compatibility between float material and process liquid.
• Tighten threaded or flanged connections securely.
• Check electrical wiring before commissioning.

Maintenance

Periodic maintenance should include:

• Inspecting float movement.
• Cleaning deposits on the guide stem.
• Checking reed switch operation.
• Inspecting cable connections.
• Replacing worn components when necessary.

9. Why Choose the Magnetic Float Level Switch?

The Magnetic Float Level Switch has become one of the preferred liquid level control solutions for industrial applications because it offers:

• Reliable switching performance.
• High durability.
• Simple construction.
• Easy installation.
• Flexible configuration.
• Compatibility with numerous liquids.
• Low maintenance requirements.
• Cost-effective operation.
• Long service life.

10. Quotation and Technical Consultation

The price of a Magnetic Float Level Switch depends on several factors, including:

• Float material.
• Guide stem material.
• Number of switching points.
• Electrical contact type.
• Connection type.
• Installation length.
• Operating pressure.
• Operating temperature.
• Explosion-proof or weatherproof enclosure type.
• Quantity ordered.

For an accurate quotation and professional technical consultation, please contact our engineering team. We are ready to assist in selecting the most suitable Magnetic Float Level Switch solution for your liquid level monitoring and control applications.