Frequently asked questions

HUADA makes industrial compressed-air equipment: magnetic levitation and centrifugal machines, two-stage and single-stage permanent magnet variable-speed (PM-VSD) screw compressors, oil-free dry screw and scroll compressors, screw blowers, screw vacuum pumps, piston compressors and refrigerated air dryers. See all products.

HUADA is the flagship brand of Fujian Huade Group, founded in Quanzhou, Fujian, China in 1985. The operating company is Quanzhou Huade Mechanical & Electrical Equipment Co., Ltd. The plant covers 50,000 m², and HUADA exports to more than 20 countries with 80 global service points. See About HUADA.

An oil-injected (lubricant-injected) screw compressor injects oil into the compression chamber to lubricate, seal and cool; separators and filters then remove the oil from the air. An oil-free compressor compresses without oil in the compression chamber, so no oil is added to the air by the compression process. Oil-injected machines usually cost less to buy and run; oil-free machines remove one source of oil contamination. Which one you need depends on the air quality your process requires, specified as an ISO 8573-1 class at the point of use.

Not by itself. An oil-free compressor does not add oil during compression, but the air it takes in can carry oil vapour from the surroundings. What matters is the purity class you require at the point of use, so specify the ISO 8573-1 class for oil, water and particles, and add dryers and filters where the process needs them.

ISO 8573-1 is the international standard that classifies compressed-air purity for three contaminants: solid particles, water (humidity) and oil. Each is rated in numbered classes, where a lower number means cleaner air, and Class 0 is a stricter class defined by agreement between the equipment supplier and the user. Air quality is written as three numbers, one for particles, water and oil. HUADA holds third-party attestations of conformity for the oil content of the outlet air of its oil-free models, measured with ISO 8573 test methods; see Certifications.

In two-stage compression the air is compressed in two steps, with cooling between the stages. Cooling the air between stages reduces the work needed for the second step compared with compressing in one step, which is why two-stage designs are used for efficiency and for higher pressures. Two stages also add a second rotor set and a cooling path to maintain, so whether it pays off depends on running hours, pressure and load. HUADA’s two-stage machines combine two-stage compression with an IE5 permanent magnet motor. See Two-stage PM-VSD screw compressors and TVD+.

A permanent magnet (PM) synchronous motor uses magnets in the rotor instead of induced current, so rotor copper losses are largely avoided. IE5 is the highest (“ultra-premium”) class in the IEC motor efficiency classification. The class describes the motor alone, not the whole compressor package, so ask for system-level test data when you compare machines.

PM-VSD stands for permanent magnet motor with a variable-speed drive. The drive adjusts motor speed to follow compressed-air demand, so the compressor does not have to run at full speed all the time. This is most useful where air demand varies during the day.

The HDTC-600 is an oil-free, direct-drive air compressor on active magnetic bearings, with four-stage compression, subject to final technical agreement. Indicative specifications are on the product page. With no mechanical contact and no lubricating oil, there are no oil changes or oil filters to manage. See the HDTC-600 page and the brochure under Resources.

The more of the following you can send, the faster we can recommend a configuration: required flow (m³/min) and working pressure (bar); air-quality class (ISO 8573-1) or application; hours of operation per day; power supply (voltage and frequency); site conditions (ambient temperature, air-cooled or water-cooled); and destination country. If you are not sure, describe your application and we will help.

Use the enquiry form or email Huangzehua@fj-hd.com. Send us your requirements and we will get back to you by email.

Yes, we welcome enquiries from OEMs, package builders, distributors and EPC contractors; the enquiry form has a company-type field for this. Tell us what you need and the volume you expect. Any technical commitment, such as customised specifications, is given only after confirmation by our technical department.

Lead time depends on the model, configuration and order quantity, and we confirm it in the quote. To quote delivery, we ask for your destination country and port or address, and the trade terms you prefer (for example EXW, FOB or CIF). Please also tell us if you need export packing or specific shipping documents.

Certificates are valid for the models and scope stated on the original documents, and copies are available on request. The site lists HUADA’s ASME “U” and “UM” stamps, National Board registration, EU PED Module B and D, ISO 14001 and ISO 45001 certificates, and the oil-content attestations, under Certifications. Data sheets are available for any series on request.

HUADA supports customers through a network of 80 global service points. Tell us your country in the enquiry form and we will explain what support is available for your location.