Ingersoll Rand SM/SL/SH37 Oil-free Screw Air Compressor Sierra Series
Performance and Specifications
This series of two-stage oil-free variable frequency screw air compressors features user-friendly design, easy installation, and simple operation, delivering safe oil-free compressed air to support your production process requirements. Ingersoll Rand oil-free screw air compressors have undergone rigorous testing and certification by TÜV Rheinland® to achieve the latest ISO 8573-1:2010 Class Zero air certification. Featuring multiple patented designs, these units build upon over a century of Ingersoll Rand innovation in compressor technology, delivering reliable and efficient compressed air systems for users.
• Product Overview
The Ingersoll Rand Sierra® Series two-stage compression zero-oil screw air compressor features a time-tested design incorporating multiple industry-leading technologies. Paired with a robust two-stage compression module, UltraCoat™ coating technology, a unique triple-seal design, 46°C ambient temperature capability, reliable bearing components, and an intelligent control system, it delivers an efficient zero-oil compressed air solution.
• Product Features
Rugged Two-Stage Compression Module
Ingersoll Rand compressor air ends are renowned for zero downtime and minimal maintenance costs. The Sierra® unit employs a two-stage compression host. Twin-screw compression reduces thermal load across each compression stage. The second-stage rotors are constructed from stainless steel to resist moisture and corrosion. The rotor surfaces are mechanically sprayed with Ingersoll Rand's patented UltraCoat™ coating, ensuring excellent sealing between rotors and guaranteeing sustained air volume without degradation over time.
The AIR EDN housing's isolation chamber employs oil-cooled jackets, differing from conventional water-cooled jackets to prevent scale buildup.
The second-stage rotor is constructed from stainless steel.
• Unique UltraCoat™ UltraCoat
Ingersoll Rand's unique UltraCoat™ super coating utilizes a molybdenum disulfide matrix compound, offering high hardness and exceptional adhesion while providing outstanding oxidation resistance. The rotor coating is applied via robotic spraying, ensuring uniform coverage across the rotor surface. Prior to coating, the screw rotor undergoes specialized shot peening to enhance surface roughness, facilitating superior coating adhesion.
The exceptional performance of the UltraCoat™ coating enables users to achieve sustained air delivery without volume decay over extended compressor operation. Most manufacturers use softer Teflon coatings applied non-uniformly without robotic spraying. During continuous operation, these coatings gradually peel off due to thermal expansion/contraction and moisture corrosion, leading to increased rotor clearance and reduced airtightness. This typically causes 8%-10% air volume decay, increasing overall unit operating costs.
Taking a 200kW unit operating for 8,000 hours as an example, an 8% air volume reduction translates to:
8% × 200 kW × 0.7 RMB/kW·hr × 8,000 hrs = 89,600 RMB in additional electricity consumption losses.
• Superior sealing design ensures oil-free compressed air chambers.
The unit employs a unique triple-seal design, completely isolating the lubricated bearing oil circuit from the air circuit to guarantee oil-free compressed air.
- SS Air Seal – Prevents air ingress into oil circuits (bearing housings / gears)
- Labyrinth Seal – Prevents oil ingress into the main unit
- Oil Drain Seal – If leakage occurs in the above seals, the oil drain seal vents oil to the atmosphere
• High Ambient Temperature Design
The units are engineered for subtropical environments with high temperatures and humidity, with a maximum design ambient temperature of 46°C, thereby preventing shutdowns caused by summer heat. All Sierra® water-cooled and air-cooled units operate reliably in harsh conditions.
• Highly Reliable Components
- Bearings
Each Sierra® host stage features roller bearings at the inlet end to support radial loads on the screw rotors via line contact. Additionally, angular contact ball bearings are installed at the outlet end to withstand axial thrust. Oil-free screw compressor rotors require extremely tight clearances to ensure top-tier efficiency. Angular contact ball bearings precisely maintain the rotors in a specially engineered position. This bearing design significantly reduces compressor failure rates and extends overhaul intervals.
• Intake System
The Sierra® intake valve is hydraulically controlled for high reliability, differing from some manufacturers' rubber diaphragm valve drives that require frequent maintenance and replacement.
A combined intake and exhaust valve controls loading/unloading. During loading, the butterfly valve fully opens while the exhaust valve closes; during unloading, the butterfly valve closes, allowing air to circulate through a small orifice in the valve disc and simultaneously actuating the exhaust valve to vent.
Oil vapors discharged from the oil-free screw compressor's tank vent cap are expelled directly with hot air outside the housing. This ensures the host unit inhales absolutely oil-free air.
• Equipment Manufacturing and Inspection Standards
Reference Standards
While complying with standards mandated by local governments, Ingersoll Rand imposes stricter additional standards on unit engineering parameters and performance.
- Electrical Components: Compliant with NFPA 70/79, IEC 60204, GB 5226-1 standards
- Performance Testing and Reference Standards: ISO 1217 Annex C; 1996
- Noise Testing Method: ISO 2151:2004
- Noise Measurement Standard: ISO 9614-2:1996, Noise Level at Workstation +3 dB(A)
- Pressure Vessels (Varies by Region):
ASME Pressure Vessel Code; Section VIII, Division 1, “Unfired Pressure Vessel”
87/404/EC Simple Pressure Vessel Directive or 97/23/EC Non-Simple Pressure Vessel Directive GB 150 (1998) Steel Pressure Vessel Standard
§ Quality Assurance
The Seller warrants that the ordered goods are manufactured from high-quality materials and standard processes, are brand new and unused, and fully comply with the quality, specifications, and performance stipulated in this Contract. The Seller further warrants that the goods ordered under this Contract, when properly installed, used, and maintained, shall be free from defects for a period of 18 months from the date of shipment from the port of export, or 12 months from the date of commissioning, whichever occurs first.
§ Ingersoll Rand China
Since its founding in China in 1922, Ingersoll Rand has been committed to building long-term partnerships with suppliers, manufacturers and customers in China. At present, Ingersoll Rand has 1 investment company, a number of trading companies, 8 manufacturing bases, 1 Asia-Pacific technology research and development center in China, and business organizations in more than 30 cities across the country.
Ingersoll Rand's largest factory in the world is located in Wujiang Industrial Park, Suzhou, covering an area of 230,000 square meters, with a construction area of 91,000 square meters and more than 700 employees. The production, quality inspection and quality control of the products will be completed in Ingersoll Rand Wujiang Industrial Park; Its supplier site evaluation, production part approval process, incoming material quality control, warehouse inventory management, manufacturing process, testing and inspection, finished product quality control, outgoing quality control and warranty are all strictly based on Ingersoll Rand's global quality regulations.![]()
