FRD Combination Dryers

In most factories, compressed air is called the fourth utility. But the air leaving an air compressor is not actually clean — it carries a large amount of water vapour, which condenses into water once it cools in the pipe network. Corroded piping, sticking pneumatic valves, water marks in spray finishes and damp, mouldy products — the source of many faults that are hard to explain lies right here.

The Fusheng FRD Series combined dryer was created precisely to solve this problem. It integrates refrigerated and desiccant drying in one unit, covers a flow rate of 1.2–90 m³/min, and offers both air-cooled and water-cooled forms, so enterprises of different sizes and site conditions can find a matching air drying solution.

Why Compressed Air Needs Drying

Once air is compressed, the water vapour content per unit volume rises sharply. Taking a common 0.7 MPa condition as an example, the air volume is compressed to about one-eighth of the original, the partial pressure of water vapour rises accordingly, and any slight drop in temperature causes the excess moisture to precipitate. If this water is not removed before the air enters the pipe network, it will flow along the pipes to every point of use, becoming a source of corrosion and faults.

The indicator of how dry the air is is the pressure dew point — the temperature at which air begins to precipitate moisture at a given pressure. The lower the dew point, the drier the air. Different processes differ widely in their dew point requirements, which is why drying equipment must be selected in tiers.

What "Combined" Combines

Common air drying equipment falls into two types: the refrigerated dryer cools the air by refrigeration so moisture condenses and drains out, with low cost and stable operation; the desiccant dryer uses a desiccant to adsorb moisture, achieving a lower dew point but consuming some air in the regeneration process.

The FRD combined dryer links the strengths of both in series: refrigerated drying for initial moisture removal, then desiccant drying for deep drying, controlling running costs while achieving a lower pressure dew point. For users who want both air quality and low energy consumption, this combination is often better value than a single type.

Air-Cooled or Water-Cooled: Let the Site Conditions Decide

The FRD Series offers both air-cooled (FRD-A Series) and water-cooled (FRD-W Series) forms. The air-cooled model dissipates heat with fans and needs no supporting circulating water system, making it flexible to install and highly mobile, suited to sites where water is inconvenient or investment in a cooling water system is not worthwhile; the water-cooled model removes heat through cooling water, with higher heat dissipation efficiency and less sensitivity to ambient temperature, better suited to production sites with a larger flow rate and long continuous operation.

The two differ in power consumption, dimensions and weight in the specification table, so selection should take plant conditions and cooling water supply into account together.

Technical Specifications

Two points stand out from this table: first, the flow range is wide — the 1.2–90 m³/min span covers everything from a small workshop to a large air-consuming site; second, air-cooled and water-cooled run in parallel, so users do not have to modify their site conditions to accommodate the equipment.

Who It Suits

• Manufacturing enterprises with precise air-consuming equipment that is sensitive to moisture;
• Industries with higher air quality requirements, such as spray finishing, packaging, food and pharmaceuticals;
• Factories operating in humid southern regions or high summer temperatures;
• Enterprises whose existing single-stage drying equipment cannot meet dew point requirements and needs upgrading;
• Users with a wide flow range who may expand in future and want a single selection to leave margin.

Selection Advice

1. First clarify the pressure dew point required at the point of use, and judge from it whether single-stage drying is enough or a combined unit is needed;
2. Size the model to the maximum air demand with margin, to avoid long full-load operation or frequent loading and unloading;
3. Prefer water cooling when there is stable circulating water and a larger flow rate on site; choose air cooling when water is limited or mobile layout is needed;
4. Do not skip the matching filters and drain traps, which together with the dryer determine the final air quality.

Conclusion

Air drying is not a nice-to-have but the foundation for whether a compressed air system can run stably over the long term. With its integrated combined design, the FRD Series puts refrigeration and adsorption into one unit, letting enterprises choose air-cooled or water-cooled models as needed across a wide 1.2–90 m³/min range. Keeping water out of the pipe network means many problems can be avoided from the very start.