Air Operated Diaphragm Level Switch (ADS) – Pune Techtrol

The Air Operated Diaphragm Level Switch is a reliable and low-maintenance solution for detecting liquid levels in vessels operating under atmospheric conditions, especially for high-viscosity liquids, sewage, and dirty oil.

This switch is designed to provide trouble-free operation and requires minimal maintenance, provided it is installed properly with an airtight seal.

Air Operated Diaphragm Level Switch

The air-operated diaphragm level switch construction includes a neoprene diaphragm sandwiched between a retainer and an enclosure, which houses a micro switch that can be actuated by as little as 1-2 mm of vertical motion from the diaphragm.

The rising liquid level submerges the air pipe, compressing the captive air column and initiating diaphragm motion to operate the micro switch while the falling liquid level sets the switch to OFF.

This switch offers an Actuation Point, Release Point, and Switch Differential defined by the length of the liquid head (mm) above the air pipe’s open end, making it an ideal solution for detecting and controlling liquid levels in vessels under atmospheric conditions.

Specifications of Air Operated Diaphragm Switch

• Range: upto 2000mm
• Wtd Parts: PP, SS316
• Max. Temp: 60ºC
• Max. Pressure: Atm
• Contacts: 5A, 250VAC x SPDT
• Enclosure: Cast Al x IP66

Installation of Air Operated Diaphragm Level Switch

When installing the air-operated diaphragm level switch, it is important to follow specific steps to ensure proper operation.

Firstly, the switch can be installed vertically or through an elbow for side installation, and the air pipe should be enlarged at the lower end for highly viscous liquids.

During installation, it is crucial to ensure that the diaphragm is horizontal and the connection between the air pipe and switch is airtight with no leaks to avoid switch malfunction.

The process connection of the switch should match that on the tank, and the length of the air pipe should be 50mm more than the required operating level.

To avoid leakage, it is recommended to use sealing paste instead of tape for a firmly sealed joint. For highly viscous liquids, the lower end of the switch pipe should be enlarged.

Ensure that the air pipe used for ADS has no blow holes or leaks.

Air Operated Diaphragm Switch Maintenance

Maintenance is important to ensure the proper functioning of Air Operated Diaphragm Level Switches.

The following steps should be taken:

1. Frequent cleaning of switches is necessary if the liquid being measured has a high viscosity or contains floating material.
2. Check the terminal connections regularly to make sure they are tight and secure.
3. Inspect the switch mechanism’s contacts for signs of pitting or oxidation due to sparking.
4. Always keep the switch enclosure cover in place to protect the mechanism.
5. Before opening the switch, disconnect it from the power supply to prevent ignition in hazardous atmospheres.

Precautions

Precautions should be taken when installing and using an air-operated diaphragm level switch. Firstly, it is essential to ensure that the sealing between the air pipe and switch process connection is airtight to prevent any malfunctioning of the switch. Using sealing paste or sealant can help achieve a perfect airtight seal. Secondly, the switch should be mounted in a way that ensures the diaphragm rests horizontally.

Thirdly, when the switch is used for measuring lower liquid levels, air and gases can become trapped inside the pipe. Therefore, it is recommended to ventilate the sensor pipe from time to time.

Fourthly, since the switch works on Pascal’s law, any change in the cross-sectional area of the air pipe can result in a change in the level detection position. Lastly, the switch works on micro-pressure and cannot be used on pressurized tanks.

Troubleshooting of Air Operated Diaphragm Switch

Some of the problems and solutions of Air Operated Diaphragm Level Switches are mentioned below.