Filter drier

Pollution and moisture in the refrigeration system can cause many problems and even disrupt the system's performance completely. In order to avoid these problems in the refrigeration cycle, filter drier is installed on refrigeration cycle lines. Filter drier is one of the most common types of filters in cooling and air conditioning systems. Main task of filter drier is to remove fine, dust and coarse solids, oil, moisture and acid from the refrigerant. The filter drier is usually installed on the liquid line after receiver and before the expansion valve, before the compressor in suction line, and in some cases, in the oil return path to the compressor.

Filter drier types 

In terms of structure

Filter driers are structurally manufactured in two main models; Hermetic and semi hermetic filter drier or changeable core one.

• Hermetic filter drier

This type of filter drier is used for lower capacity systems such as refrigerators, small chillers and air conditioning systems. For this model its core can’t be changed and after a while it need be replace with new one.

• Semi hermetic filter drier

In large capacity systems like chiller application semi hermetic filter drier is most common. This type of filter drier consists of two parts; Shell and Core. In this type just the core whose main task is absorbing pollution and moisture of system is changed and the shell is steady.

In terms of water and acid absorption

Filter driers is divided into three categories in terms of absorption:

•  Acid absorbent

This type of drier is mostly used in the suction line to absorb acid, especially during system repairs and compressor protection.

• High water absorbent

The type has the ability to absorb the maximum amount of moisture in the refrigeration system and are usually installed in the suction and liquid lines.

• High acid and water absorbent

In cases where both water and acid absorption are considered, this type of drier is used and usually installed in liquid and suction lines.