Compressed air dryer
Definition and Purpose
In pneumatic automation, maintaining the quality of compressed air is crucial for optimal system performance. To achieve this, a comprehensive range of drying units is available, designed to effectively remove moisture from compressed air. These drying technologies ensure that the air delivered to your systems is dry, thereby enhancing efficiency and extending the lifespan of pneumatic components. Whether you require refrigeration, membrane, or adsorption dryers, there are tailored solutions to meet the varying demands of your applications. Below, we explore the different drying procedures and their specific benefits.
Types of compressed air dryers
In practice, there are three different procedures that can be used to dry compressed air.
- Areas of application for types of dryer (Source: Hoerbiger-Origa)
- 3 Refrigeration dryer up to 1000 m³/h
- 2 Membrane air dryer
- 1 Adsorption dryer
1. Refrigeration dryers
Generally speaking, a refrigeration dryer should be placed downstream of each compressor. The air is cooled to just above freezing in a cooling unit, and the condensate that falls off is drained away. In order to save on energy costs, heat is exchanged between the cold dried air and the warm air that still needs to be dried. The pressure dew point is then approx. 3 °C. Since the safety margin to the pressure dew point needs to be 10 K, this is sufficient for systems whose operating temperature never drops below 13 °C.
2. Membrane air dryers
Lower the pressure dew point. Membrane air dryers from Festo lower the pressure dew point by 20 K, for example. The air flows longitudinally through a bundle of parallel, hollow fibres. During this process, water vapour diffuses because of a partial pressure drop from the inside of the fibres to the outside. The vapour is drained out using purge air. Due to the purge air, the maintenance-free dryer has a certain amount of constant bleed.
3. Adsorption dryers
They are used when pressure dew points of –70°C are required. The dryers use molecular forces to bond gas or vapour molecules to a drying agent. Since the drying agent is regenerative, two chambers are required: while drying takes place in one, in the other the drying agent has time for cold or warm regeneration. In devices with cold regeneration, such as those offered by Festo, some of the dried air is used to dry the adhesion agent. When warm regeneration is used, the water evaporates as heat is applied. The drying agent must be replaced regularly
In membrane and adsorption dryers, the higher the inlet pressure, the better the efficiency. The inlet pressure should therefore be as high as possible. In addition, a certain amount of caution is required with some connection materials. Hemp joints on piping, for example, are air-tight, but may still draw in water from the ambient air and channel it into the system.
Compressed Air Dryers from Festo
Festo offers a diverse range of drying solutions to meet the needs of various pneumatic applications.
Within the MS Series line, our membrane air dryers effectively lower the pressure dew point, ensuring high-quality, moisture-free compressed air. These maintenance-free units utilize advanced technology to enhance efficiency while minimizing operational costs, making them an ideal choice for a variety of applications.
In addition, our adsorption dryers, available through the Individual Devices category, are designed for applications requiring extremely low pressure dew points. These dryers utilize molecular forces to bond gas or vapor molecules to a regenerative drying agent, providing reliable performance in demanding environments. With these innovative products, Festo is committed to delivering effective air preparation solutions that enhance the reliability and efficiency of your pneumatic systems.