Oil Free Air Compressors

Available Dezhou YITong oil-free and clean-air configurations

The authorised Dezhou YITong / Yitongsuolan product display identifies three product lines with individual product records: dry oil-free low-pressure screw compressors, water-lubricated oil-free screw compressors, and clean-air oil-free medium/high-pressure compressor packages. A separate permanent-magnet variable-speed clean-air package is also described in the company product display. The table distinguishes the published labels from the data that still needs to be fixed in a project quotation.

The published kW bands below are fields labelled as model ranges on the company website. They are not package electrical-input figures, motor ratings at a named duty, or a promise that every configuration is currently available. The website does not publish a model-by-model, reference-condition flow table for these products. Where a source uses an undefined “cubic” specification or the Chinese pressure term “公斤”, this page keeps that limitation instead of converting it into a performance claim.

• Use the dry oil-free series when its confirmed low-pressure duty, flow and control range suit the process; the product page alone is not a flow curve.
• Use the water-lubricated series only after the supplier confirms the pressure, water-side requirements and the exact delivered-air specification.
• Treat the clean-air medium/high-pressure package as a complete compressor-and-treatment proposal. Its product description does not establish dry compression or a final ISO class at your outlet.

Compare the compression and treatment configuration

Oil-free describes the compression process only when the selected machine actually avoids lubricating oil in the compression chamber or air path. The mechanical arrangement matters: ask the supplier to name the air-contacting stages, coatings, seals, coolers and any auxiliary fluids. A water-lubricated design should be assessed as its own technology, with water quality, materials, drains and service access defined for the proposed package.

The published clean-air medium/high-pressure product uses different language. Its description refers to air separation plus a refrigerated dryer and cyclone water removal, and says it can replace dry oil-free equipment. That is a reason to request a written description of the compression air path and the complete treatment train. It is not a basis for calling the package dry oil-free, or for treating a low residual-oil statement as a point-of-use certification.

For an oil-injected compressor with filters, do not use the oil-free label. It may be a valid alternative only if the supplier documents the complete treatment train and the process owner accepts the specified delivered-air quality. Compare duty, pressure loss, cooling, controls, maintenance and verification requirements instead of comparing a label or motor size alone.

Specify the delivered-air package, not the compressor alone

Start with the contamination endpoint. Define whether the concern is particles, liquid water, water vapour, oil aerosol, oil vapour, microorganisms or a combination. ISO 8573-1:2010 classifies compressed-air purity for particles, water and oil at the location where air is specified or measured. State the three contaminant limits, the sampling location, operating condition and test method; a compressor, filter or dryer component statement is not proof that a remote outlet meets the same result.

The compressor, aftercooler, separator, dryer, filters, receiver and distribution network should be reviewed as a sequence. Cooling changes the water load presented to downstream equipment. Filters introduce pressure drop and need flow, pressure and service data; a dryer needs its inlet conditions and dew-point basis. A receiver can buffer a demand event and reduce rapid control cycling, but it cannot replace capacity or the treatment required for the specified air quality.

The medium/high-pressure clean-air product description specifically refers to refrigerated drying and cyclone treatment. Ask the supplier to provide the arrangement drawing, separator and dryer duty, drain points, pressure drop at clean and loaded condition, bypass protection and maintenance boundary. Add particulate, coalescing, vapour or point-of-use stages only when the identified contaminant risk and the required delivered-air class warrant them.

Match the published series to the process requirement

The dry oil-free low-pressure product page names bottle blowing, textiles, material conveying, sand blasting and mask-machine fibre blowing as example applications. The water-lubricated product page names food, medical, chemical and bottle-blowing equipment where compressed air has a stated requirement. These are published application examples, not automatic suitability statements. The pressure, flow, cleanliness and operating profile must be checked against the actual equipment or process specification.

An oil-free configuration is a rational starting point where an oil event could affect product, process surfaces or a sensitive instrument, or where the owner wishes to reduce dependence on oil-removal stages. It is not automatically the preferred choice for every plant. A general workshop may place more weight on duty stability, purchase scope, service availability, heat rejection and electrical supply. Conversely, an oil-free machine may be unsuitable if its cooling, water quality, ambient limits or maintenance support do not fit the site.

For food, pharmaceutical, laboratory, electronics, breathing-air or other critical duties, do not infer product safety, microbiological control or a regulatory approval from the compressor description. Define the process contact assessment, governing specification, required purity class and acceptance test with the responsible process owner.

Plan utilities, installation and maintenance before selection

Confirm the site ambient temperature range, ventilation path, cooling-water temperature and quality where applicable, electrical voltage and fault level, room access, drainage and noise limits. Ventilation must be assessed for the compressor and dryers together. Ask for footprint, lifting points, service clearances, connection sizes and start-up requirements before approving the layout. For water-lubricated equipment, include the water-side quality, treatment, freeze protection and drain plan in the supplier response.

Pressure is a system requirement, not simply a compressor nameplate value. Allow for treatment, valves, filters, distribution losses and the minimum pressure required by the critical user. Specify whether pressure is gauge or absolute. State every flow reference condition and require derating assumptions for high elevation, unusual intake temperature or a restricted inlet.

Maintenance intervals depend on the selected technology, OEM instructions, ambient conditions, duty and cooling medium. Request a model-specific maintenance schedule, consumables list, inspection tasks, recommended spares and service-access drawing. Include treatment equipment: drains, filters, dryer components, sensors and any point-of-use elements can have separate inspection and replacement requirements.