Опис
ZW-8/6 Nitrogen Compressor – Compact Oil-Free N2 Booster for Low-Pressure Industrial Gas Systems
Engineered to deliver 8 m³/min at 0.60 MPa discharge pressure, the ZW-8/6 is a two-stage, two-row oil-free piston nitrogen compressor designed for small-scale cryogenic air separation, laboratory nitrogen supply, and compact VPSA booster stations. Zero oil contamination, space-efficient footprint, and optimized for intermittent to continuous-duty operation.
Огляд продукту
The ZW-8/6 nitrogen compressor represents a compact yet capable solution within our oil-free piston compressor family, specifically tailored for small-scale nitrogen boosting applications where space constraints and operational simplicity are paramount. With a rated capacity of 8 m³/min and a discharge pressure of 0.60 MPa, this unit occupies the entry-level segment of our industrial nitrogen compressor portfolio while maintaining the same engineering rigor as our larger models.
The ZW-8/6 distinguishes itself through a completely oil-free compression mechanism utilizing self-lubricating PTFE composite piston rings and rider bands. This design philosophy eliminates any possibility of hydrocarbon contamination in the nitrogen product stream, making the unit immediately suitable for laboratory-grade nitrogen, small-batch food packaging, pharmaceutical R&D, and electronics assembly line inerting without additional downstream purification equipment.
Its two-stage, two-row (二列二级) configuration delivers a higher pressure ratio than single-stage alternatives while maintaining thermal stability through inter-stage cooling. The compact dimensions—2250 × 1296 × 2200 mm—allow the ZW-8/6 to fit into existing machinery rooms, containerized installations, or mobile nitrogen supply skids where floor space is at a premium. At just 2.00 tonnes, the unit can be transported and positioned without heavy-lift equipment.
Technical Specifications – ZW-8/6
| Параметр | Value | Unit |
|---|---|---|
| Модель | ZW-8/6 | – |
| Візерунок | Two-stage, Two-row (二列二级) | – |
| Місткість | 8 | м³/хв |
| Тиск нагнітання | 0.60 | МПа |
| Compressor Size (L × W × H) | 2250 × 1296 × 2200 | mm |
| Вага | 2.00 | t |
| Потужність | 55 | кВт |
| Напруга | 380 | V |
| Газове середовище | Nitrogen (N₂) | – |
| Lubrication | Без олії | – |
* All specifications are rated at standard reference conditions (ISO 1217, Annex C). Actual performance may vary based on site altitude, ambient temperature, and inlet conditions.
Key Features & Engineering Advantages
1. Compact Footprint for Space-Constrained Installations
At 2250 × 1296 × 2200 mm, the ZW-8/6 occupies less than 3 m² of floor space, making it one of the most compact oil-free nitrogen compressors in its capacity class. This dimensional efficiency is achieved through a vertically oriented crankcase design that minimizes the machine’s longitudinal footprint while maintaining adequate maintenance access. The 2.00-tonne weight permits installation using standard forklift equipment, eliminating the need for overhead cranes or specialized rigging during commissioning or relocation.
2. Oil-Free PTFE Sealing Technology
The ZW-8/6 employs a self-lubricating piston ring and rider band system constructed from high-performance PTFE composites. These rings operate with a coefficient of friction below 0.08 without any hydrocarbon lubricant, delivering ISO 8573-1 Class 0 oil content in the compressed nitrogen stream. For small-scale users such as analytical laboratories, food R&D facilities, and electronics manufacturers, this native oil-free certification eliminates the capital expense and maintenance burden of downstream oil-filtration systems that would otherwise be mandatory.
3. Two-Stage Compression for Higher Pressure Ratios
The two-stage, two-row architecture divides the pressure ratio between a low-pressure cylinder and a high-pressure cylinder, with an inter-stage shell-and-tube cooler removing the heat of compression. This staged approach limits the discharge temperature of each stage to below 150°C, preventing thermal degradation of the PTFE sealing elements and extending valve plate life by approximately 30% compared to single-stage compressors operating at equivalent overall pressure ratios. The 0.60 MPa discharge pressure is particularly well-suited for medium-pressure nitrogen distribution in small industrial facilities.
4. Standard 380V Direct-On-Line Motor Drive
The ZW-8/6 is powered by a 55 kW, 380V, 50Hz three-phase induction motor rated to IEC 60034-1 IE3 efficiency class. The standard low-voltage configuration integrates directly into existing 380V industrial distribution panels without requiring medium-voltage infrastructure, step-down transformers, or specialized switchgear. This electrical simplicity reduces both capital expenditure and commissioning complexity, making the ZW-8/6 an attractive option for facilities upgrading from bottled nitrogen or membrane generators to on-site compression.
Application Scenarios
Small-Scale Cryogenic Air Separation Units
In compact cryogenic ASU installations producing 200–500 Nm³/h of gaseous nitrogen, the ZW-8/6 serves as the primary nitrogen booster between the cold box and the distribution network. Its 8 m³/min capacity aligns with the output of small-scale ASUs, while the 0.60 MPa discharge pressure provides sufficient head for distribution to nearby process equipment, laboratory fume hoods, or storage tank blanketing systems. The oil-free design is critical in these applications because small ASUs typically lack the extensive purification trains found in large facilities, making downstream oil contamination particularly problematic.
Compact VPSA Nitrogen Booster Stations
For small to medium VPSA nitrogen generators producing 99.5–99.9% purity nitrogen at near-atmospheric pressure, the ZW-8/6 nitrogen booster compresses the low-pressure product to 0.60 MPa for distribution. The compact footprint of the ZW-8/6 allows it to be mounted on the same skid as the VPSA generator, creating a fully integrated nitrogen supply system that occupies minimal floor space. The oil-free compression path protects the carbon molecular sieve from hydrocarbon poisoning, preserving the generator’s separation efficiency and extending adsorbent life.
Laboratory & Analytical Gas Supply
Research laboratories, analytical chemistry facilities, and university science departments require a reliable supply of high-purity nitrogen for gas chromatography, mass spectrometry, and inert atmosphere glove boxes. The ZW-8/6’s oil-free certification ensures that the nitrogen stream meets the stringent purity requirements of analytical instruments without requiring additional purification cartridges. The 8 m³/min capacity can support multiple GC-MS systems, ICP-MS instruments, and glove boxes operating simultaneously within a single laboratory building.
Electronics Manufacturing & Soldering Inerting
In electronics assembly facilities, nitrogen is used for wave soldering inerting, reflow oven atmosphere control, and component storage dry cabinets. The ZW-8/6’s 0.60 MPa discharge pressure is adequate for feeding nitrogen distribution manifolds serving multiple soldering lines and storage cabinets. The oil-free design is non-negotiable in electronics applications because even trace oil contamination can cause solder joint defects, conformal coating adhesion failures, and contamination of sensitive optical components.
Material & Construction
The ZW-8/6 is constructed from materials selected for nitrogen compatibility, corrosion resistance, and compact structural integrity:
| Component | Матеріал | Specification |
|---|---|---|
| Cylinder Block | Gray Cast Iron | GG25 / HT250, integral cooling passages |
| Crankshaft | Forged Alloy Steel | 42CrMo4, Q&T, dynamically balanced |
| Piston Rings | PTFE-Glass-Bronze Composite | Self-lubricating, oil-free rated |
| Rider Bands | PTFE Composite | Piston guidance, anti-scuffing |
| Valve Plates | Stainless Steel | SS316, concentric ring spring design |
| Intercooler | Carbon Steel Shell / SS304 Tubes | Compact shell-and-tube, 1.5× hydrotest |
| Base Frame | Structural Steel | Welded, vibration-damped mounting |
All pressure-bearing components conform to ASME BPVC Section VIII Division 1 or Chinese GB 150 standards. Weld joints are subjected to 100% radiographic inspection (RT), and each pressure vessel undergoes hydrostatic testing at 1.5× MAWP for a minimum 30-minute hold period before release.
Installation & Maintenance Guidelines
Foundation & Spatial Requirements
The ZW-8/6 weighs 2.00 tonnes and features a low center of gravity due to its compact vertical design. A reinforced concrete pad of 3–4 tonnes is sufficient for stable operation, mounted on elastomeric vibration isolators (natural frequency 8–12 Hz). The two-row opposed-cylinder arrangement inherently cancels first-order inertial forces, minimizing vibration transmission. Required clearances: 1.0 m on the non-drive side for valve maintenance, 0.8 m on the drive side for motor access, and 1.5 m overhead for routine service.
Cooling Water Specifications
Cooling water demand is approximately 12 m³/h at an inlet temperature not exceeding 32°C. The water distribution circuit feeds the cylinder jackets and intercooler in parallel. Acceptable water quality: pH 6.5–8.5, total hardness < 300 mg/L as CaCO₃, chloride < 50 mg/L, suspended solids < 30 mg/L. For installations without reliable municipal water supply, a compact closed-loop cooling tower with a 1 m³ buffer tank is recommended.
Maintenance Intervals
| Interval | Service Item | Action Required |
|---|---|---|
| Daily | Visual & Operational Check | Inspect for leaks, abnormal noise, cooling water flow |
| 250 hours | Valve Plate Inspection | Check for carbon deposits, spring fatigue, or plate cracking |
| 1,000 hours | Piston Ring Wear Assessment | Measure groove clearance; replace if > 0.20 mm |
| 4,000 hours | Intermediate Service | Replace piston rings, rider bands, and valve assemblies |
| 8,000 hours | Major Overhaul | Inspect crankshaft, measure bearing clearances, replace as needed |
The oil-free design of the ZW-8/6 dramatically simplifies maintenance compared to lubricated alternatives. There are no oil changes to schedule, no oil samples to analyze, no filter elements to replace, and no oil separator cartridges to monitor. The only consumable wear items are the PTFE piston rings and rider bands, which typically achieve 4,000–6,000 hours of service under clean nitrogen conditions.
Compliance & Safety Certifications
The ZW-8/6 nitrogen compressor meets the following international standards and regulatory requirements:
ASME BPVC Section VIII Div.1, GB 150-2011, PED 2014/68/EU Module A
IEC 60034-1 (IE3 efficiency), IEC 60204-1, ISO 12100
ISO 8573-1 Class 0 (Oil Content), TÜV Rheinland tested
ISO 9001:2015, ISO 14001:2015
⚠️ Safety Notice
Nitrogen is an odorless, colorless asphyxiant gas. All ZW-8/6 installations must include continuous oxygen monitoring in the compressor room and adjacent areas. Ventilation must maintain ambient oxygen above 19.5% per OSHA 29 CFR 1910.146. Alarm interlocks should trigger at 19.5% O₂ and hard shutdown at 18.0% O₂. Personnel entry into enclosed compressor rooms requires portable oxygen monitors and a buddy system.
Performance & Efficiency Analysis
The ZW-8/6 achieves a specific power consumption of approximately 6.88 kW per m³/min of nitrogen at 0.60 MPa discharge pressure. While this specific power is higher than our larger LW-series models due to the reduced scale efficiency, it remains competitive within the sub-10 m³/min oil-free piston compressor segment. For comparison, oil-lubricated screw compressors in this size range typically consume 7.2–8.0 kW/m³/min, and diaphragm compressors (often selected for oil-free applications) can exceed 10 kW/m³/min.
Over an 8,000-hour annual operating cycle, the ZW-8/6’s efficiency advantage versus less efficient alternatives yields approximately 20,000–45,000 kWh of energy savings per year. At $0.08/kWh, this represents $1,600–$3,600 in annual electricity cost reduction. However, the primary economic driver for ZW-8/6 selection is typically the elimination of oil-related consumables and downstream purification equipment rather than marginal energy savings.
The total cost of ownership for nitrogen compression in small-scale applications is dominated by maintenance labor and consumables rather than energy. The ZW-8/6’s oil-free design eliminates oil changes ($400–800/year), filter replacements ($200–400/year), separator cartridge changes ($600–1,200/year), and oil analysis ($150–300/year), delivering a total consumable savings of $1,350–$2,700 annually compared to lubricated alternatives.
Customization & OEM Capabilities
We provide flexible customization options to adapt the ZW-8/6 to specific installation constraints and end-user requirements:
- Skid-Mounted Packages: Pre-assembled compressor, motor, cooler, and control panel on a structural steel skid with forklift pockets and lifting eyes. Reduces field installation to electrical connection and cooling water hookup only.
- Mobile Trailer Units: The ZW-8/6 can be mounted on a road-legal trailer with integrated diesel generator, cooling system, and nitrogen storage, creating a fully mobile nitrogen supply unit for construction sites, pipeline maintenance, and emergency response.
- PLC & Remote Monitoring: Optional Siemens LOGO! or S7-1200 PLC with 7-inch HMI touchscreen, Ethernet connectivity, and SMS/email alarm notifications. Compatible with Modbus TCP/IP for SCADA integration.
- Acoustic Enclosures: Compact IP54-rated sound enclosure reducing noise from 82 dB(A) to 68 dB(A) at 1 meter, suitable for indoor installations in noise-sensitive environments such as laboratories and office-adjacent machinery rooms.
- OEM & Private Label: Custom paint schemes, branded nameplates, and localized documentation packages for gas equipment distributors and system integrators.
Custom configurations are available from MOQ 1 unit. Engineering proposals are typically delivered within 3–5 business days. Standard delivery time is 10–12 weeks; expedited delivery within 8 weeks is available for qualifying orders.
Case Study: Laboratory Nitrogen Supply Upgrade
Client: A pharmaceutical research institute in Singapore
Challenge: The institute was purchasing liquid nitrogen in 200-liter dewars and vaporizing on-site for laboratory supply. Monthly nitrogen consumption reached 15,000 Nm³, with delivery costs, dewar rental fees, and vaporization losses consuming 40% of the annual gas budget. Additionally, liquid nitrogen deliveries were unreliable during public holidays and inclement weather, causing experiment delays.
Solution: We supplied a ZW-8/6 oil-free nitrogen compressor paired with a small VPSA nitrogen generator (99.9% purity, 10 m³/min) on a common skid. The ZW-8/6 boosts the VPSA product from 0.08 MPa to 0.60 MPa for distribution through the existing laboratory nitrogen header. The entire system occupies 8 m² in a corner of the building’s utility room.
Results After 18 Months:
- Nitrogen supply cost: Reduced by 52% versus liquid nitrogen purchase and delivery
- Supply reliability: 100% uptime since commissioning, zero experiment delays due to gas shortage
- Nitrogen purity: Consistently >99.9% with oil content <0.01 mg/m³, exceeding analytical instrument requirements
- Maintenance burden: One scheduled service per year (4,000-hour interval), versus monthly dewar changeovers
- Payback period: 2.4 years based on gas cost savings alone
“The ZW-8/6 compressor has transformed our nitrogen supply from a logistical headache into a reliable utility. Our researchers no longer worry about gas availability, and the finance department appreciates the 50% cost reduction.” — Facilities Manager, Pharmaceutical Research Institute
FAQ & Selection Guide
Related Products & Solutions
LW Series Large-Capacity Nitrogen Compressors
High-flow oil-free piston compressors (20–130 m³/min) for cryogenic ASU backup, VPSA boosting, and industrial pipeline distribution. Discharge pressures from 0.30 to 0.80 MPa.
DW Series High-Pressure Nitrogen Compressors
Medium to high-pressure oil-free compressors (0.40–2.00 MPa) for nitrogen injection, pipeline boosting, and chemical synthesis. Capacities from 2 to 130 m³/min.
MW Series Medium-Pressure Compressors
Medium-pressure oil-free compressors (1.0–4.0 MPa) for nitrogen recycle, gas liquefaction, and process gas compression in petrochemical operations.
For a complete overview of our industrial nitrogen compressor portfolio, including oil-free oxygen compressors, hydrogen compressors, and specialty gas solutions, please contact our engineering team or browse our online catalog.
Ready to Upgrade Your Nitrogen Supply?
Our application engineers are available to review your nitrogen flow requirements, inlet conditions, and discharge pressure specifications. We provide complimentary technical proposals, layout drawings, and TCO analyses within 48 hours.
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