What is a Vent Filter? – Water Treatment Plant

Water treatment has many processes running inside it for proper water purification. It has many stages like pre-treatment, generation, and distribution. Distribution is the last step where water is provided for use. So, it will be required that the final water present inside be always pure, which will ensure zero contamination to users.

The water is already pure in the distribution storage tank. But, to prevent any further contamination from entering the water, one main component is used in the storage tank. This equipment is called a vent filter.

In this post, we will learn the concept of a vent filter.

Vent Filter

Water is present inside the tank along with air. Air is required to balance the pressure inside the tank. This pressure must be at the atmospheric or ambient level. It must neither be less or more, otherwise, the vacuum will be created inside. It is normal for a tank when under operation, to work under pressure.

But, when vacuum pressure is created, the tank inside material starts to wear and tear slowly. After a certain time, it will crack the internal layers. In the worst-case scenario, the water can even start to spill out of the vessel. It is important to maintain the pressure inside the tank. This will require proper air to be present inside the tank.

As a tank is filled, the air inside must be allowed to escape. Inversely, as the tank is emptied, the air or gas must be allowed to enter the tank to replace the lost liquid volume. All this shows that air is required in a proper balance inside the tank.

For this, an inlet is provided in the tank for air control. If the air entering inside is filled with dust, bacteria, micro-organisms, or any other contaminant, then this impure air will enter the tank and eventually contaminate the water. So, it is required that clean air enters or leaves the tank. This brings the use of a vent filter here.

A vent filter is an equipment that is installed on the tank, to ensure clean air is maintained inside the tank. Also, as the tank has water, water pores can get developed frequently in the filter.

So, the filter is controlled by an internal electrical heater, which works at a set temperature to heat the accumulated water and keep the filter dry. If the filter pores are filled with water, then airflow is blocked and a vacuum will develop inside a tank being emptied. A vent filter thus helps to maintain proper air pressure inside the tank.

In industrial automation, in the water distribution process, the vent filter is always controlled by PLC. It is turned on and off depending on the temperature to help avoid water pore formation and thus keep the filter dry. Eventually, if the filter is dry, then the air too will be filtered properly.

In this way, we understand the concept of vent filters in industrial automation.