{"id":549,"date":"2026-07-20T03:53:41","date_gmt":"2026-07-20T03:53:41","guid":{"rendered":"https:\/\/n2-compressor.com\/?post_type=product&p=549"},"modified":"2026-07-20T03:54:16","modified_gmt":"2026-07-20T03:54:16","slug":"zw-4-8-nitrogen-compressor","status":"publish","type":"product","link":"https:\/\/n2-compressor.com\/ar\/product\/zw-4-8-nitrogen-compressor\/","title":{"rendered":"ZW-4\/8 Nitrogen Compressor \u2013 Precision Oil-Free N2 Booster for High-Pressure Small-Scale Applications"},"content":{"rendered":"
\n

<\/p>\n

\n

ZW-4\/8 Nitrogen Compressor \u2013 Precision Oil-Free N2 Booster for High-Pressure Small-Scale Applications<\/h1>\n

Delivering 4 m\u00b3\/min at 0.80 MPa discharge pressure, the ZW-4\/8 is a two-stage, two-row oil-free piston nitrogen compressor engineered for high-pressure laboratory supply, precision instrument inerting, and compact industrial nitrogen boosting where elevated pressure and absolute purity are non-negotiable.<\/p>\n

\u0627\u0637\u0644\u0628 \u0639\u0631\u0636 \u0633\u0639\u0631<\/a>
\nView N2 Compressor Series<\/a><\/div>\n

\"ZW-4\/8<\/p>\n<\/div>\n

<\/p>\n

\n

\u0646\u0638\u0631\u0629 \u0639\u0627\u0645\u0629 \u0639\u0644\u0649 \u0627\u0644\u0645\u0646\u062a\u062c<\/h2>\n

The ZW-4\/8 nitrogen compressor<\/strong> is a precision-engineered oil-free piston compressor designed for applications where high discharge pressure and compact footprint must coexist. With a rated capacity of 4 m\u00b3\/min<\/strong> and an elevated discharge pressure of 0.80 MPa<\/strong>, this unit addresses the demanding requirements of high-pressure nitrogen distribution in laboratory complexes, precision manufacturing facilities, and small-scale industrial processes.<\/p>\n

Unlike conventional compressors that compromise on either pressure capability or purity, the ZW-4\/8 achieves both through a fully oil-free compression mechanism<\/strong>. The piston rings and rider bands are manufactured from advanced self-lubricating PTFE composites that operate without hydrocarbon lubricants, ensuring the nitrogen stream remains completely free of oil contamination. This native oil-free characteristic is essential for applications such as GC-MS carrier gas supply, pharmaceutical sterile processing, and semiconductor wafer handling where even trace oil vapor can compromise product integrity.<\/p>\n

The two-stage, two-row (\u4e8c\u5217\u4e8c\u7ea7)<\/strong> architecture is specifically optimized for the 0.80 MPa discharge pressure target. By distributing the pressure ratio across two compression stages with inter-stage cooling, the ZW-4\/8 maintains discharge temperatures within safe limits while achieving the higher pressure output that single-stage designs cannot reach. The compact dimensions of 2250 \u00d7 1296 \u00d7 2200 mm<\/strong> and a weight of just 2.00 tonnes<\/strong> make this unit suitable for installation in confined machinery rooms, mobile skids, and containerized nitrogen supply systems.<\/p>\n

\"ZW<\/p>\n<\/div>\n

<\/p>\n

\n

Technical Specifications \u2013 ZW-4\/8<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\nUnit<\/th>\n<\/tr>\n<\/thead>\n
\u0646\u0645\u0648\u0630\u062c<\/td>\nZW-4\/8<\/td>\n\u2013<\/td>\n<\/tr>\n
\u0646\u0645\u0637<\/td>\nTwo-stage, Two-row (\u4e8c\u5217\u4e8c\u7ea7)<\/td>\n\u2013<\/td>\n<\/tr>\n
\u0633\u0639\u0629<\/td>\n4<\/td>\n\u0645\u00b3\/\u062f\u0642\u064a\u0642\u0629<\/td>\n<\/tr>\n
\u0636\u063a\u0637 \u0627\u0644\u062a\u0641\u0631\u064a\u063a<\/td>\n0.80<\/td>\n\u0645\u064a\u062c\u0627 \u0628\u0627\u0633\u0643\u0627\u0644<\/td>\n<\/tr>\n
Compressor Size (L \u00d7 W \u00d7 H)<\/td>\n2250 \u00d7 1296 \u00d7 2200<\/td>\nmm<\/td>\n<\/tr>\n
\u0648\u0632\u0646<\/td>\n2.00<\/td>\nt<\/td>\n<\/tr>\n
\u0642\u0648\u0629<\/td>\n30<\/td>\n\u0643\u064a\u0644\u0648\u0648\u0627\u0637<\/td>\n<\/tr>\n
\u0627\u0644\u062c\u0647\u062f \u0627\u0627\u0644\u0643\u0647\u0631\u0628\u0649<\/td>\n380<\/td>\nV<\/td>\n<\/tr>\n
\u0648\u0633\u0637 \u063a\u0627\u0632\u064a<\/td>\nNitrogen (N\u2082)<\/td>\n\u2013<\/td>\n<\/tr>\n
Lubrication<\/td>\n\u062e\u0627\u0644\u064d \u0645\u0646 \u0627\u0644\u0632\u064a\u0648\u062a<\/td>\n\u2013<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

* 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.<\/em><\/p>\n<\/div>\n

<\/p>\n

\n

Key Features & Engineering Advantages<\/h2>\n

1. High-Pressure Oil-Free Piston Technology<\/h3>\n

The ZW-4\/8 employs a self-lubricating piston ring and rider band assembly<\/strong> fabricated from high-density PTFE composites reinforced with glass fiber and bronze particulates. These rings achieve a coefficient of friction below 0.08 without any external lubrication, delivering ISO 8573-1 Class 0 oil content<\/strong> certification in the compressed nitrogen stream. This is particularly critical for high-pressure applications where oil contamination would be amplified by the pressure ratio, making downstream oil removal exponentially more difficult and expensive.<\/p>\n

2. Two-Stage Compression for Elevated Pressure Ratios<\/h3>\n

The two-stage, two-row architecture<\/strong> is thermodynamically essential for achieving the 0.80 MPa discharge pressure from typical nitrogen generator outlet pressures of 0.05\u20130.10 MPa. The first-stage cylinder compresses the nitrogen to an intermediate pressure of approximately 0.25\u20130.30 MPa, after which an inter-stage cooler removes the heat of compression. The second-stage cylinder then raises the pressure to the final 0.80 MPa target. This staged approach limits the discharge temperature of each stage to below 160\u00b0C, preventing thermal degradation of the PTFE sealing elements and maintaining valve plate integrity under the elevated pressure duty.<\/p>\n

3. Compact Footprint with High Power Density<\/h3>\n

At 2250 \u00d7 1296 \u00d7 2200 mm<\/strong>, the ZW-4\/8 occupies less than 3 m\u00b2 of floor space while delivering 0.80 MPa discharge pressure\u2014a combination that is difficult to achieve with alternative compressor technologies. The compact vertical crankcase design minimizes the longitudinal footprint while providing adequate access for routine maintenance. The 2.00-tonne weight<\/strong> permits transportation and positioning using standard forklift equipment, making the ZW-4\/8 suitable for retrofit installations in existing machinery rooms, mobile nitrogen supply skids, and containerized process units.<\/p>\n

4. Efficient 380V Motor Drive<\/h3>\n

The ZW-4\/8 is driven by a 30 kW, 380V, 50Hz three-phase induction motor<\/strong> conforming to IEC 60034-1 IE3 efficiency class. The standard low-voltage configuration integrates directly into existing 380V industrial distribution panels without requiring specialized medium-voltage infrastructure. This electrical simplicity is particularly valuable for small-scale facilities, laboratories, and mobile installations where medium-voltage switchgear would be prohibitively expensive. The 30 kW power rating provides an excellent balance between compression capability and electrical demand, keeping operating costs manageable for intermittent-duty applications.<\/p>\n

\"ZW-4\/8<\/p>\n<\/div>\n

<\/p>\n

\n

Application Scenarios<\/h2>\n

High-Pressure Laboratory Nitrogen Supply<\/h3>\n

Research laboratories and analytical facilities require high-pressure nitrogen for gas chromatography carrier gas, mass spectrometry nebulizer gas, and inert atmosphere glove box supply. The ZW-4\/8’s 0.80 MPa discharge pressure<\/strong> is sufficient to feed high-pressure nitrogen regulators and distribution manifolds serving multiple instruments simultaneously. The oil-free certification ensures that the nitrogen stream meets the stringent purity requirements of analytical instruments without requiring additional purification cartridges or oil-monitoring instrumentation. The 4 m\u00b3\/min capacity can comfortably support 8\u201312 GC-MS systems or 4\u20136 ICP-MS instruments operating in parallel.<\/p>\n

\"ZW-4\/8<\/p>\n

Precision Manufacturing & Semiconductor Inerting<\/h3>\n

In electronics and semiconductor manufacturing, nitrogen is used for wafer handling inerting, reflow oven atmosphere control, and component storage dry cabinets<\/strong>. The ZW-4\/8 high-pressure nitrogen compressor<\/a> delivers the 0.80 MPa pressure required for precision pressure regulators that maintain sub-atmosphere inert environments in glove boxes and wafer transfer chambers. The oil-free design is absolutely critical in these applications because even nanogram-level oil contamination can cause solder joint defects, conformal coating adhesion failures, and contamination of optical surfaces on precision components.<\/p>\n

Pharmaceutical Sterile Processing & Aseptic Filling<\/h3>\n

Pharmaceutical manufacturing facilities use high-pressure nitrogen for aseptic filling line inerting, vial headspace displacement, and freeze-dryer chamber purging<\/strong>. The ZW-4\/8’s 0.80 MPa discharge pressure provides the head necessary to feed nitrogen through HEPA-filtered distribution systems and precision pressure regulators that maintain sterile barrier pressures in isolators and restricted access barrier systems (RABS). The oil-free certification ensures compliance with FDA 21 CFR 211.72 (equipment construction) and EU GMP Annex 1 (sterile medicinal products) without requiring additional oil-removal validation.<\/p>\n

\"ZW-4\/8<\/p>\n

Small-Scale VPSA Nitrogen Booster<\/h3>\n

For compact VPSA nitrogen generators producing 99.5\u201399.9% purity nitrogen at near-atmospheric pressure, the ZW-4\/8 compresses the low-pressure product to 0.80 MPa for high-pressure distribution. The compact footprint allows the compressor to be mounted on the same skid as the VPSA generator, creating an 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 by preventing irreversible contamination.<\/p>\n<\/div>\n

<\/p>\n

\n

Material & Construction<\/h2>\n

The ZW-4\/8 is constructed from materials selected for high-pressure nitrogen compatibility, corrosion resistance, and long-term mechanical reliability:<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
Component<\/th>\n\u0645\u0627\u062f\u0629<\/th>\nSpecification<\/th>\n<\/tr>\n<\/thead>\n
Cylinder Block<\/td>\nGray Cast Iron<\/td>\nGG25 \/ HT250, integral cooling passages<\/td>\n<\/tr>\n
Crankshaft<\/td>\nForged Alloy Steel<\/td>\n42CrMo4, Q&T, ISO 1940 G2.5 balanced<\/td>\n<\/tr>\n
Piston Rings<\/td>\nPTFE-Glass-Bronze Composite<\/td>\nSelf-lubricating, oil-free rated<\/td>\n<\/tr>\n
Rider Bands<\/td>\nPTFE Composite<\/td>\nPiston guidance, anti-scuffing<\/td>\n<\/tr>\n
Valve Plates<\/td>\nStainless Steel<\/td>\nSS316, concentric ring spring design<\/td>\n<\/tr>\n
Intercooler<\/td>\nCarbon Steel Shell \/ SS304 Tubes<\/td>\nCompact shell-and-tube, 1.5\u00d7 hydrotest<\/td>\n<\/tr>\n
Aftercooler<\/td>\nCarbon Steel Shell \/ SS304 Tubes<\/td>\nFinned tube design, 32\u00b0C cooling water<\/td>\n<\/tr>\n
Base Frame<\/td>\nStructural Steel<\/td>\nWelded, vibration-damped mounting<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

All pressure-bearing components are designed and fabricated in accordance with ASME BPVC Section VIII Division 1<\/strong> or Chinese GB 150 standards. Weld joints undergo 100% radiographic inspection (RT), and each pressure vessel is subjected to hydrostatic testing at 1.5\u00d7 the maximum allowable working pressure (MAWP) for a minimum hold time of 30 minutes.<\/p>\n

\"ZW-4\/8<\/p>\n<\/div>\n

<\/p>\n

\n

Installation & Maintenance Guidelines<\/h2>\n

Foundation & Spatial Requirements<\/h3>\n

The ZW-4\/8 weighs 2.00 tonnes and features a low center of gravity due to its compact vertical design. A reinforced concrete pad of 3\u20134 tonnes<\/strong> is sufficient for stable operation, mounted on elastomeric vibration isolators (natural frequency 8\u201312 Hz). The two-row opposed-cylinder arrangement inherently cancels first-order inertial forces, minimizing vibration transmission to sensitive laboratory equipment or precision manufacturing machinery nearby. 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.<\/p>\n

Cooling Water Specifications<\/h3>\n

Cooling water demand is approximately 8 m\u00b3\/h<\/strong> at an inlet temperature not exceeding 32\u00b0C. The water distribution circuit feeds the cylinder jackets and intercooler in parallel. Acceptable water quality: pH 6.5\u20138.5, total hardness < 300 mg\/L as CaCO\u2083, chloride < 50 mg\/L, suspended solids < 30 mg\/L. For laboratory installations without dedicated cooling water infrastructure, a compact air-cooled aftercooler option is available, eliminating the need for water supply entirely.<\/p>\n

Preventive Maintenance Schedule<\/h3>\n
\n\n\n\n\n\n\n\n\n\n
Interval<\/th>\nService Item<\/th>\nAction Required<\/th>\n<\/tr>\n<\/thead>\n
Daily<\/td>\nVisual & Operational Check<\/td>\nInspect for leaks, abnormal noise, cooling water flow<\/td>\n<\/tr>\n
250 hours<\/td>\nValve Plate Inspection<\/td>\nCheck for carbon deposits, spring fatigue, or plate cracking<\/td>\n<\/tr>\n
1,000 hours<\/td>\nPiston Ring Wear Assessment<\/td>\nMeasure groove clearance; replace if > 0.20 mm<\/td>\n<\/tr>\n
4,000 hours<\/td>\nIntermediate Service<\/td>\nReplace piston rings, rider bands, and valve assemblies<\/td>\n<\/tr>\n
8,000 hours<\/td>\nMajor Overhaul<\/td>\nInspect crankshaft, measure bearing clearances, replace as needed<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

The oil-free design of the ZW-4\/8 dramatically reduces maintenance complexity 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<\/strong>, which typically achieve 4,000\u20136,000 hours of service under clean nitrogen conditions.<\/p>\n

\"ZW-4\/8<\/p>\n<\/div>\n

<\/p>\n

\n

Compliance & Safety Certifications<\/h2>\n

The ZW-4\/8 nitrogen compressor meets or exceeds the following international standards and regulatory requirements:<\/p>\n

\n
Pressure Equipment<\/strong>
\nASME BPVC Section VIII Div.1, GB 150-2011, PED 2014\/68\/EU Module A<\/span><\/div>\n
Electrical & Machine Safety<\/strong>
\nIEC 60034-1 (IE3 efficiency), IEC 60204-1, ISO 12100<\/span><\/div>\n
Oil-Free Certification<\/strong>
\nISO 8573-1 Class 0 (Oil Content), T\u00dcV Rheinland independently tested<\/span><\/div>\n
Quality & Environmental<\/strong>
\nISO 9001:2015, ISO 14001:2015<\/span><\/div>\n<\/div>\n
\n

\u26a0\ufe0f Safety Notice<\/strong><\/p>\n

Nitrogen is an odorless, colorless asphyxiant gas. All ZW-4\/8 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% O\u2082 and hard shutdown at 18.0% O\u2082. Personnel entry into enclosed compressor rooms requires portable oxygen monitors and a buddy system. High-pressure nitrogen systems must be equipped with pressure relief devices rated to ASME BPVC Section VIII requirements.<\/p>\n<\/div>\n

\"ZW-4\/8<\/p>\n<\/div>\n

<\/p>\n

\n

Performance & Efficiency Analysis<\/h2>\n

The ZW-4\/8 achieves a specific power consumption of approximately 7.50 kW per m\u00b3\/min<\/strong> of nitrogen at 0.80 MPa discharge pressure. While this specific power is higher than our larger LW-series models due to the reduced scale efficiency inherent in small-capacity compressors, it remains competitive within the sub-5 m\u00b3\/min high-pressure oil-free piston segment. For comparison, oil-lubricated screw compressors in this pressure and size range typically consume 8.0\u20139.5 kW\/m\u00b3\/min, and diaphragm compressors (often selected for oil-free high-pressure duty) can exceed 12 kW\/m\u00b3\/min.<\/p>\n

Over an 8,000-hour annual operating cycle, the ZW-4\/8’s efficiency advantage versus less efficient alternatives yields approximately 12,000\u201332,000 kWh of energy savings<\/strong> per year. At $0.08\/kWh, this represents $960\u2013$2,560 in annual electricity cost reduction. However, the primary economic driver for ZW-4\/8 selection is typically the elimination of oil-related consumables and downstream purification equipment<\/strong> rather than marginal energy savings.<\/p>\n

The total cost of ownership for high-pressure nitrogen compression<\/a> in small-scale applications is dominated by maintenance labor and consumables. The ZW-4\/8’s oil-free design eliminates oil changes ($300\u2013600\/year), filter replacements ($150\u2013300\/year), separator cartridge changes ($400\u2013800\/year), and oil analysis ($100\u2013200\/year), delivering total consumable savings of $950\u2013$1,900 annually compared to lubricated alternatives. Additionally, the elimination of downstream oil-removal equipment (coalescing filters, activated carbon adsorbers, oil monitors) saves $3,000\u2013$8,000 in capital expenditure.<\/p>\n<\/div>\n

<\/p>\n

\n

Customization & OEM Capabilities<\/h2>\n

We provide flexible customization options to adapt the ZW-4\/8 to specific installation constraints and end-user requirements:<\/p>\n