Summary of Side-Mounted Magnetic Level Indicator

The side-mounted magnetic level indicator is a very reliable and visible piece of level measurement equipment used to measure the level of liquid in a tank and vessel. It is fitted on the side of the tank and is made up of a float having an inner magnet that rises and falls with the liquid level. This float is in a chamber linked to the process vessel, and its position is monitored by a magnetically coupled indicator outside the chamber, usually a flag or flap display that changes color as the level varies.

This form of indicator is non-invasive, process-sealed, and mechanical, and thus can be used in corrosive, toxic, or pressurized applications. It is widely applied in chemical processing, oil and gas, power plants, and water treatment to monitor the level continuously and to control the level with an alarm.

Side-mounted magnetic level indicators have a long service life and are maintenance-free with high visibility, even under harsh industrial environments, since there is no direct contact between the indicator and the liquid.

Principle of operation of side-mounted magnetic level indicator

A side-mounted magnetic level indicator uses the principle of magnetic coupling of a float and an external indicator to visually indicate the level of liquid within a tank or vessel.

The Way It Works

Internal Magnet Float

It is composed of a hollow float inside a vertical chamber (external to the main tank) on the side of the tank, which is filled with a permanent magnet. This chamber is interconnected with the tank through top and bottom process connections whereby the liquid will rise and fall within this chamber as the level of the tank changes.

Movement of Liquid Level

The float inside the indicator chamber moves up or down as the level rises or falls in the liquid in the tank.

Magnetic Coupling

Internally the float is magnetically actuated by a magnet to an external indicator system (e.g., flappers, rollers, or a follower) mounted outside the chamber. This is a non-contact magnetic interaction that permits level indication without the exposure to the fluid.

Visual Indication

The visual indication is read directly and continuously externally by a visible pointer (usually a red/white color flap mechanism or moving pointer) that gives a clear visual indication of the fluid level. Additional accessories such as transmitters or switches may be added to allow remote monitoring and control.

Applications of Side-Mounted Magnetic Level Indicator

A side-mounted magnetic level indicator is a level indicator that is widely used, particularly in the constant and safe observation of level in pressurized or hazardous tanks. It is based on the principle of a float where a magnet is embedded in the center, and it rises and falls with a change in the level of liquid in a chamber situated on the side of a tank. As the float moves, it also drives an external magnetic display or transmitter.

Typical Uses

Chemical and Petrochemical Industries

To monitor corrosive, toxic, or hot liquids in reactors, tanks, and vessels.

Oil and gas

Applied in refineries, offshore platforms, and storage terminals to indicate the level of crude oil, fuel, condensate, or water.

Water treatment plants

A great fit in clarifiers, dosing tanks, and chemical storage tanks where visibility and protection are a concern.

Food Processing and Pharmaceutical

They are used in sanitary or hygienic tanks where external reading is non-contact, so contamination is reduced.

Steam Systems and Boilers

It is suitable in high-pressure steam boilers and condensate tanks, and safe and accurate level detection is available.

Power Plants and Utilities

Applied to cooling water, turbine oil, and fuel storage in severe environments.

Benefits of side-mounted magnetic level indicator

High Visibility

Uses a magnetic float and external indicator (usually with flaps or rollers) to indicate the level of liquid clearly and continuously.

No Power Needed

Mechanically activated, requiring no electricity to perform basic visual indication of level, which makes it perfect in hazardous or remote locations.

Safe and Secured Design

The entire process fluid is contained, and it can safely be used when toxic, corrosive, or high-pressure fluid is required without danger of leaks or contamination.

Low Maintenance

The lack of moving parts exposed to the process fluid makes the system wear-, corrosion-, and clogging-resistant and low maintenance.

Side-Mounted Magnetic Level Indicator disadvantages

Poor Precision with foamy or viscous liquids

Reading accuracy may be impaired by float movement not being possible in foamy, sticky, or high-viscosity fluids.

Installation Constraints

Needs side nozzles and sufficient vertical room on the tank not always appropriate in tight or unusual vessels.

Unsuitable to Detect Interface

Difficulty in measuring the interface between two immiscible liquids (e.g. oil and water) unless specially prepared.

Able to detect change in density

Specific gravity is necessary to float calibration; large changes in fluid density may impact performance and accuracy.

Greater Cost of First Installation than of Simple Gauges

Cost more than sight glasses or simple level indicators, particularly where switches or transmitters are applied.

Installation of Side-Mounted Magnetic Level Indicator

A side-mounted magnetic level indicator is a device mounted on the side of a tank or vessel to give a continuous

Visual level indication by means of a float and magnetic coupling. Proper installation guarantees proper and stable performance.

Step-by-step installation guide

Site Preparation

Make sure the tank or vessel is depressurized and drained during installation.

Confirm the nozzles on the connection (typically flanged or threaded) with the indicator process connections.

Wipe the connection ports of any debris, corrosion, or welding slag.

Orientation and Mounting

Mount the indicator vertically next to the tank and center it on the top and bottom process nozzles.

Install the unit with matching flanges, gaskets, or threaded couplings.

Make sure that the float is already in the chamber and at the right place to take the desired range of measurements.

Flange/Connection Tightening

Apply a consistent torque pattern when tightening flange bolts so as to prevent misalignment.

Use the right sealant or gaskets where indicated.

Do not overtighten; this can lead to damage of the chamber or the sealing surfaces.

Look out for barriers

Ensure the chamber does not have any obstruction that might prevent the movement of floats.

Ensure that the float is free to move in the chamber as the level varies.

Engineering—Magnetic Display Alignment

Make sure that the indicator flap display (or roller assembly) is placed in the appropriate position relative to the float travel path.

Certain models can need prior calibration or zero-point adjustment.

Recommendation on Disposal of Side-Mounted Magnetic Level Indicator

When disposing of a side-mounted magnetic level indicator, it is important to be careful so as to be safe and environmental. The first step is to isolate the indicator to the process line and ensure that the system is depressurized and drained. Thoroughly clean the unit, particularly when the unit has been in contact with hazardous, corrosive, or flammable fluids.

Most such devices consist of metallic components (typically stainless steel chambers and mounting hardware) and a magnetic float and are occasionally fitted with indicator flags or electronic transmitters.

After cleaning, the metal parts may be sent to scrap metal recycling.

Magnetic floats, when sealed and any internal liquid or sensitive parts, should be examined to determine whether they contain hazardous materials and disposed of as industrial waste.

In case the unit has a transmitter or sensor, then the unit must be discarded as electronic waste (e-waste) in certified facilities.

To dispose of the indicator in a safe and sustainable way, always refer to the guidelines of the manufacturer and follow the local regulations regarding environmental and hazardous waste.