EP-CM75G Water-Lubricated Oil-Free Screw Air Compressor for PET Bottle Blowing
The EP-CM75G is a 75 kW single-screw water-lubricated oil-free compressor delivering 6.3 m³/min at up to 4.0 MPa (40 bar) — engineered exclusively for PET bottle blowing lines where ISO 8573-1 Class 0 air purity, zero oil contamination, and continuous 24/7 reliability are absolute production requirements.
EP-CM75G | 75 kW Fixed-Speed Water-Lubricated Oil-Free Compressor — 40 Bar for PET Blowing
PET bottle blowing is one of the most pressure-demanding and contamination-sensitive compressed air applications in modern manufacturing. Shaping a preform into a finished PET bottle at 30–40 bar requires air that is simultaneously at extreme pressure, completely free of oil, and delivered with absolute consistency — the moment a production compressor fails any one of these requirements, entire bottle batches are scrapped, blow molds are damaged, and downstream filling lines grind to a halt.
The EP-CM75G water-lubricated oil-free screw compressor was designed from the ground up to meet these demands. Drawing on Ever Power's single-screw compression technology — originally developed in partnership with global packaging industry standards bodies — the EP-CM75G delivers 6.3 m³/min (222 cfm) of ISO 8573-1 Class 0 certified oil-free compressed air at pressures up to 4.0 MPa (40 bar) in a single compression stage, without multi-stage intercoolers, piston rings, or any lubricating oil anywhere in the system.
Water performs four simultaneous functions inside the EP-CM75G's compression chamber: it lubricates the single screw and star wheel contact surfaces, seals the compression clearances to maintain volumetric efficiency, cools the air during compression to achieve near-isothermal conditions, and carries heat away from the air end continuously. The result is a discharge air temperature that never exceeds 45°C above ambient — a fundamental thermodynamic advantage over dry oil-free screw and reciprocating piston designs that operate at 150–200°C. For food and beverage packaging operators, this low discharge temperature also means a dramatically lower condensation load on downstream dryers, reducing dryer energy consumption and extending desiccant service life. Learn more about Ever Power's full range of oil-free compressor solutions for packaging and process industries.
Complete Technical Specifications
| Parameter | Specification |
|---|---|
| Model | EP-CM75G |
| Drive Type | Fixed frequency (direct drive) |
| Motor Power | 75 kW / 100 HP |
| Working Pressure | 2.0 – 4.0 MPa (290 – 580 psi / up to 40 bar) |
| Free Air Delivery (FAD) | 6.3 m³/min | 222 cfm |
| Noise Level | 70 dB(A) |
| Weight | 2100 kg |
| Dimensions (L×W×H) | 2750 × 1250 × 1480 mm |
| Compression Stage | Single stage (single screw + star wheel) |
| Lubrication Medium | Pure water (zero oil in system) |
| Discharge Temp. | ≤ ambient + 15°C (≤ 45°C typical) |
| Air Quality | ISO 8573-1 Class 0 (Oil: 0 ppm) |
| Certifications | TUV (Germany) / ISO 9001 / ISO 14001 |
| Design Service Life | > 25 years (7×24 h continuous operation) |
Single-Screw Water Lubrication: The Technology Behind 40 Bar Oil-Free Compression
The compression mechanism of the EP-CM75G centres on a precision-machined single screw meshing with two star wheels positioned symmetrically on opposite sides. This geometry creates a theoretically balanced force condition: radial and axial loads cancel each other, generating virtually zero net load on the main screw shaft. The practical result is that the screw can operate continuously at the relatively low rotational speed of approximately 3,000 rpm — roughly half the speed of conventional twin-screw compressors — without generating the mechanical stress that shortens service life in high-speed designs.
Water is injected directly into the compression chamber throughout the operating cycle, fulfilling four simultaneous roles that no dry gas can replicate: it lubricates the screw-star wheel interface without contaminating the air supply; it seals the micro-clearances between screw and housing to maintain volumetric compression efficiency; it absorbs compression heat continuously, maintaining a compression chamber temperature only 15°C above ambient; and it carries that heat through the plate heat exchanger water cooler, from which it is discharged at temperatures below 55°C. This isothermal compression process is not merely a theoretical advantage — it directly reduces specific power consumption by 10% or more compared to non-isothermal alternatives at equivalent pressure and flow.
Key Components of the EP-CM75G
① Permanent Magnet Motor
Customized rare-earth permanent magnet motor with IP54 protection grade, Class F insulation, and built-in SKF bearings. Motor efficiency is 3–5% above standard motors, capable of 7×24 hours of continuous non-stop operation without performance degradation.
② Stainless Steel Air End
The fully stainless steel air end — independently developed and patented by Ever Power — features ultra-high volumetric efficiency and a patented no-shaft-sealing design. With a designed service life exceeding 25 years, the air end is the heart of the EP-CM75G's longevity and oil-free guarantee.
③ High-Efficiency Air Intake Valve
Self-patented, integrated lowest-point air intake design improves compression efficiency, reduces suction noise, and extends air filter service life. The unique openable modular box structure allows filter element replacement without disconnecting pipework.
④ Water & Air Separation Barrel
Constructed entirely in stainless steel with a special internal streamline design. Air flow velocity inside reaches 10 m/s, ensuring complete moisture separation. Water settles to the bottom and is discharged through the minimum pressure valve, leaving dry compressed air at the outlet.
⑤ Lubricating Water Filtration System
Stainless steel shell with CMN-original glass fiber cotton multi-layer filter elements providing 0.1 μm filtration accuracy. Filtered water extends air end service life by maintaining the cleanliness of the lubrication medium throughout the operational cycle.
⑥ Logic PLC Control System
French Schneider Electric control system with advanced fault monitoring, early warning functions, and a friendly human-machine interface. Displays all operating parameters in real time and adjusts drive motor speed to maintain pressure within a narrow ±0.1 MPa band, maximising efficiency and reliability.
⑦ Plate Water Cooler
High-performance multi-process plate heat exchanger that multiplies the effective cooling area compared to conventional shell-and-tube designs. Discharge air temperature is kept below 55°C under all rated operating conditions, protecting downstream equipment and maintaining compressed air quality.
Technology Comparison: Water-Lubricated vs Alternatives
| Feature | EP-CM75G Water-Lubricated | Dry Oil-Free Screw | Reciprocating Piston |
|---|---|---|---|
| Oil in system | None — zero oil | None in chamber, oil in bearings | Oil-free versions: no oil; lubricated: oil present |
| Air end speed | ~3,000 rpm | 6,000–25,000 rpm | 300–1,500 rpm |
| Compression chamber temp. | Ambient +15°C | ~200°C | 150–250°C |
| Max single-stage pressure | 40 bar | ~13 bar (needs booster) | 40 bar (multi-stage) |
| Number of compression air ends | 1 | 2 | 3–4 stages |
| Number of bearings | 7 | >15 | >15 |
| Number of seals | Patented no-shaft-sealing | >15 | >15 |
| Energy saving vs traditional | >10% (isothermal compression) | Baseline | Higher consumption |
| Design service life | >25 years | 10–15 years | 8–12 years |
System Configuration for PET Bottle Blowing Lines
The EP-CM75G is designed for integration into a complete compressed air system serving PET stretch blow molding machines. The water-cooled configuration — the standard for this model — connects to a facility cooling water circuit or cooling tower for heat rejection. For installations without cooling water infrastructure, an air-cooled variant is available. Both configurations follow the same downstream treatment sequence to achieve the final air quality required at the blow mold.
PET Bottle Application Scenarios: Pressure Selection Guide
| Bottle / Product Type | Typical Pressure | Industry | EP-CM75G Suitability |
|---|---|---|---|
| Standard drinking water bottles (≤1.5L) | 30–35 bar | Bottled water | ✅ Optimal |
| Carbonated soft drink bottles | 35–40 bar | Beverage | ✅ Full capacity |
| Edible oil bottles | 30–38 bar | Food | ✅ Optimal |
| Large-format water jugs (5L+) | 38–40 bar | Water dispensing | ✅ Full capacity |
| Pharmaceutical / cosmetic bottles | 28–35 bar | Pharma / cosmetics | ✅ Optimal |
Certifications & Quality Assurance
The EP-CM75G carries Germany TUV-verified ISO 8573-1 Class 0 certification covering oil content (0 ppm), particulates (Class 0), and moisture (Class 0) — the most stringent air purity standard defined by the ISO classification system. This is not a filter-dependent or maintenance-conditional certification; Class 0 status is structurally guaranteed by the water lubrication mechanism, which contains no oil that could contaminate the air supply under any operating condition. The manufacturing facility is certified under ISO 9001:2015 and ISO 14001:2015.
Customer Case Studies
Brazil — Mineral Water Bottling Plant
Industry: Bottled Water | Application: 40 bar air supply for 500ml PET bottle blowing line
"We replaced 14 ageing piston compressors with a single EP-CM75G. The noise reduction alone transformed our production floor — from 95 dB to 70 dB. But the real gain was the elimination of oil contamination failures that were causing periodic batch scrapping. In 20 months of operation, we have had zero oil-related quality rejections and our maintenance team now spends less than 4 hours per month on compressor servicing."
★★★★★
Australia — Edible Oil Packaging Manufacturer
Industry: Food Packaging | Application: 38 bar oil-free air for HDPE/PET edible oil bottle blowing
"Our FSANZ food safety certification requires documented Class 0 oil-free air throughout the production environment. The EP-CM75G's TUV certification gave our auditor everything needed to sign off immediately. The single-stage compression to 38 bar also simplified our compressed air infrastructure significantly — we removed two booster compressors and their associated maintenance requirements."
★★★★★
South Korea — Pharmaceutical Bottle Producer
Industry: Pharmaceutical Packaging | Application: 33 bar clean air for PET pharma bottle blowing under GMP conditions
"GMP guidelines for our facility require that no lubricant contamination risk exists in the compressed air used for bottle production. The EP-CM75G's water-only lubrication system — verified by TUV — provided the structural compliance we needed. The PLC monitoring system has also proven invaluable for our GMP documentation requirements, providing timestamped operating parameter logs automatically."
★★★★★
Frequently Asked Questions
Configure the EP-CM75G for Your Blowing Line
Bottling plants and packaging manufacturers across Brazil, Australia, South Korea, and 50+ countries rely on Ever Power water-lubricated compressors for their PET blowing operations. Our engineering team can review your blow mold machine specifications, production volume, and pressure requirements to confirm fit and provide a detailed system quotation — typically within 48 hours.
Factory tour
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