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DW-3.8/(4-6)-15 Nitrogen Compressor

Medium Composition (mol%): Nitrogen
Treatment Capacity: 1200 Nm³/h
Inlet Pressure: 0.4~0.6 MPa.G (Gauge Pressure)
Inlet Design Pressure: 0.5 MPa.G (Gauge Pressure)
Inlet Temperature: Ambient Temperature
Outlet Pressure: 1.4 MPa.G (Gauge Pressure)
Outlet Temperature: ≤135 ℃ (Celsius)
Terminal Gas Supply Temperature: ≤50 ℃ (Celsius)
Main Motor Power: 75 kW (Kilowatts)
Overall Dimensions: ~4800×3200×1800 mm (Millimeters)
Overall Weight: ~5 T (Tons)
Availability:
Quantity:
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Overview


The DW-3.8/(4~6)-14 Nitrogen Compressor is a high-reliability reciprocating piston compressor engineered specifically for efficient nitrogen compression. It is ideally suited for a wide range of industrial scenarios, including chemical fertilizer production nitrogen boosting, petrochemical process nitrogen protection, industrial nitrogen storage systems, and high-demand gas supply operations. This compressor maintains stable performance even under fluctuating working conditions, delivering consistent and reliable nitrogen compression solutions.



Core technical parameters underscore its operational capabilities: it takes nitrogen as the compression medium, with a rated treatment capacity of 1200 Nm³/h and a nominal volumetric flow rate of 3.8 m³/min. The inlet pressure ranges from 0.4 to 0.6 MPa.G (with an inlet design pressure of 0.5 MPa.G) and the inlet temperature is ambient, while the exhaust pressure reaches 1.4 MPa.G and the exhaust temperature is controlled at ≤135 ℃ (with a terminal gas supply temperature of ≤50 ℃ after cooling). Driven by a 75 kW main motor (model: YBX4-315M-8, second-level energy efficiency), the compressor has an overall dimension of approximately 4800×3200×1800 mm and a total weight of around 5 T. Its fixed, skid-mounted design (with a dedicated foundation) facilitates straightforward on-site installation and seamless integration into existing industrial layouts.



As a specialized nitrogen compression equipment, this model is optimized for the 1200 Nm³/h flow range and 1.4 MPa.G exhaust pressure. However, its fundamental design framework can be customized to accommodate varying flow rates and pressure requirements, making it adaptable to diverse industrial needs—from pharmaceutical industry nitrogen inerting to food processing nitrogen preservation projects.


Features


Superior Operational Stability and Extended Service Life

The DW-3.8/(4~6)-14 Nitrogen Compressor excels in stability and durability, backed by a refined structural design. It adopts a D-type (symmetrical balanced) structure with two rows and single-stage compression, which effectively minimizes mechanical vibration (in line with the GB/T7777-2021 standard) and reduces noise (meeting the GB/T4980-2003 specification). A water-cooling system is integrated to cool the cylinders, packing, and compressed nitrogen, ensuring steady operation during long-term continuous service. Key components are constructed with high-quality materials: the crankshaft is made of 45# steel (with induction-hardened crankpins for enhanced wear resistance), and the piston rod is crafted from 42CrMo (with a nitrided surface achieving a minimum hardness of HRC60). These premium components significantly prolong the equipment's service life, reducing maintenance frequency and operational costs.


Oil-Free Lubrication in Critical Zones and Medium Purity Maintenance

A standout feature of this compressor is its zone-specific oil-free lubrication design, which is vital for preserving nitrogen purity. It incorporates a double-middle-body structure, where the middle-body space is greater than one stroke—this design creates a reliable barrier to prevent lubricating oil from the crankcase from entering the cylinders and contaminating the nitrogen medium. The cylinders (made of QT600-3 ductile iron) and packing (special polytetrafluoroethylene-filled materials) adopt an oil-free configuration, eliminating the need for oil injection lubrication in these critical areas. Meanwhile, mechanical components such as the crankshaft, connecting rod, and crosshead use pressure lubrication to ensure smooth operation. This dual lubrication strategy guarantees that the compressed nitrogen meets strict purity standards, making the compressor suitable for applications like electronic manufacturing where nitrogen contamination is strictly forbidden.


Comprehensive Control and Multi-Layered Safety Protection

The compressor is equipped with a mature control system to enable safe and efficient operation. While the unit's start-up control cabinet is provided by the user, the manufacturer integrates all compressor operation and alarm signal lines into an on-site explosion-proof junction box, and supplies interlock logic diagrams/logic explanations as well as terminal wiring diagrams for the junction box. This setup supports seamless connection to the user's control system, facilitating centralized monitoring and management. In terms of safety protection, the compressor offers all-round safeguards: it conducts real-time monitoring of key parameters including lubricating oil pressure, cooling water pressure, inlet/exhaust pressure, exhaust temperature, and main motor bearing/winding temperature. Corresponding alarm or shutdown protection is triggered when parameters exceed safe limits, ensuring the compressor operates in a secure and reliable manner at all times.


Application Area


Nitrogen compressors are indispensable equipment in the industrial gas supply chain. With its 1.4 MPa.G exhaust pressure, 1200 Nm³/h treatment capacity, and zone-specific oil-free lubrication design, the DW-3.8/(4~6)-14 Nitrogen Compressor plays a critical role in multiple industrial scenarios. In chemical fertilizer production, it compresses low-pressure nitrogen (0.4~0.6 MPa.G) to 1.4 MPa.G, providing the required pressure for nitrogen-based fertilizer synthesis processes. In petrochemical plants, it is used for nitrogen purging and pressure testing of pipelines and equipment, leveraging its stable output to ensure safe maintenance and commissioning operations. In the metal processing industry, it supplies high-pressure nitrogen for metal heat treatment, creating an inert atmosphere to prevent oxidation of workpieces. Additionally, its compliance with strict explosion-proof standards (main motor explosion-proof grade: ExdIICT4) and IP55 protection grade makes it suitable for hazardous industrial environments where safe nitrogen handling is a priority.


Highlight Advantages



high efficiency operating Installation honor
Has high efficiency, strong reliability, and high degree of automation; Less vulnerable parts, low vibration, low noise, and easy operation and maintenance The main and auxiliary equipment of the compressor are all installed on the sled, running smoothly and reliably. The overall sled installation is convenient for the transportation and installation of the compressor The entire machine components are carefully designed


Patent Certificates



certificates

A piston rod thread protective sleeve ZL 2017 2 1907021.7


certificates

A piston ring support device ZL 2018 2 0294776.2

certificates

A range piston ZL 2017 2 190177.0 for symmetrical balanced compressors


certificates

Integrated long short double compartment ZL 2018 2 0294762.0


Whole Machine Description


The DW-3.8/(4~6)-14 nitrogen compressor adopts a D-type (symmetrical balance type), water-cooled, partial oil-free lubrication, reciprocating piston structure, with 2-row and 1-stage compression (double-acting), and the entire unit is supplied in a skid-mounted configuration. This integrated design simplifies on-site installation procedures and enables quick integration into existing industrial systems, reducing the time and effort required for on-site assembly.

The compressor crankcase is made of gray cast iron (HT250), which provides excellent structural rigidity and shock absorption to withstand the mechanical forces generated during operation. The crankcase is machined with two holes of different diameters, specifically designed for the installation of crosshead slides, main bearings, and bearing seats—ensuring precise alignment of moving components and minimizing operational wear. The lower cavity of the crankcase functions as a lubricating oil sump, storing the lubricant needed for the compressor's mechanical motion parts. On the upper surface of the crankcase, there is an interface for mounting an oil filler (breather) cover plate, which facilitates oil replenishment and maintains balanced internal pressure. Additionally, the crankcase is equipped with multiple functional interfaces: an oil drain port (connected to the exterior of the skid and fitted with a manual ball valve for easy oil discharge during maintenance), an oil level gauge observation port (allowing real-time visual inspection of oil levels), an oil injection port for bearing seats (enabling targeted lubrication of bearings), and a reserved interface for oil temperature sensors (supporting real-time monitoring of lubricating oil temperature).

The compressor features a double-middle-body structure, and the internal space of the middle body is designed to be larger than one stroke of the piston. This structural arrangement forms an effective barrier that prevents lubricating oil from the crankcase from migrating into the cylinders, thereby avoiding oil contamination of the nitrogen medium and ensuring the purity of the compressed nitrogen. The compressor cylinder is made of ductile iron (QT600-3), a material with high strength, good wear resistance, and excellent heat dissipation performance—well-suited to withstand the pressure and temperature changes during nitrogen compression. The cylinder adopts a radial arrangement and is equipped with dedicated intake and exhaust buffers, which help stabilize the gas flow during the intake and exhaust processes, reduce pressure fluctuations, and lower operational noise.


The compressor packing is installed from the working chamber side of the cylinder. The first small chamber adjacent to the cylinder working chamber is fitted with a flow restrictor ring, which plays a throttling role to reduce gas leakage. Several subsequent small chambers are each equipped with two sets of packing rings, made of special polytetrafluoroethylene-filled material. This material exhibits outstanding self-lubricating properties, wear resistance, and thermal conductivity, eliminating the need for oil injection lubrication in the packing area and further ensuring the oil-free condition of the compressed nitrogen. The compressor gas valves adopt an internationally popular mesh structure design, which offers large flow passages, low flow resistance, and fast opening/closing responses—effectively improving the compression efficiency and reducing energy consumption.



The compressor piston is made of either ZL108 aluminum alloy or HT250 gray cast iron, both of which are lightweight and high-strength materials that reduce the inertial force during piston movement. The piston is equipped with piston rings and guide rings, which ensure effective sealing between the piston and the cylinder wall, as well as stable guiding of the piston's reciprocating motion. The piston rod is made of 42CrMo alloy steel, with its surface subjected to nitriding treatment to achieve a minimum hardness of HRC60—greatly enhancing its wear resistance and corrosion resistance. The threads on the piston rod are manufactured using a rolling process, which improves thread strength and fatigue resistance. The piston rod is connected to the crosshead via threads, ensuring a secure and reliable connection that can withstand the alternating forces during operation.


The compressor crosshead is made of ductile iron (QT600-3), which combines high strength and good toughness. The crosshead is machined with threads for connecting the piston rod and a mounting hole for the crosshead pin (used to connect the connecting rod). Its simple and robust structure ensures reliable transmission of motion between the connecting rod and the piston rod, with minimal maintenance requirements. The main bearings of the compressor, as well as the sliding surfaces of the crosshead and the bearings of the connecting rod (both large and small ends), adopt pressure lubrication. This lubrication method delivers a continuous supply of pressurized lubricating oil to the friction surfaces, forming a stable oil film that reduces wear and dissipates heat—ensuring long-term reliable operation of the moving components.


DW-3.8 (4-6)-15 氮气 (16) DW-3.8 (4-6)-15 氮气 (19)(1)


The compressor in this picture is a non-standard product. The product provides independent solutions tailored to customers' specific usage requirements (flow rate/purity/pressure, usage environment, main purpose, and customer specific requirements), from design to product customization.


  • Structural form: D-type/M-type/S-type/W-type/V-type/Z-type

  • Cooling method: water cooling/air cooling/mixed cooling

  • Installation form: fixed/mobile/pry mounted/cabin type

  • Drive mode: motor drive/diesel engine start

  • Transportation: sea/air/land

  • Packaging:

    Metal cabin
    Wooden box
    Soundproof cabin
    Metal cabin Wooden box
    Soundproof cabin


Technical Parameter



No. Model Medium Flow rate
(Nm3/h)
Exhaust pressure
(MPa.G)
Motor power
(kW)
Cooling method Overall dimensions
(mm)
Weights
(kg)
1 DW-1.6/(8~12)-120 Hydrogen 800 12 160 Water-cooled 5800×3000×2300 8500
2 DW-1.8/15-30 Hydrogen 1500 3.0 75 Water-cooled 3200×3000×1850 5800
3 DW-6.74(3.3)/0.7(5~12)-12 Hydrogen 600 1.2 90 Water-cooled 5000×3200×2100 8000
4 DW-17.9/(4~5)-6.5 Hydrogen 1270 0.65 132 Water-cooled 3500×3000×2300 8000
5 DW-1.8/15-30 Hydrogen 1500 3.0 75 Water-cooled 3200×3000×1850 5800
6 DW-9.55/0.03-16 Hydrogen 515 1.6 90 Water-cooled 3500×3200×2500 6500
7 DW-96.5/( 15~23 )-( 21~29 ) Hydrogen 4500 2. 1~2.9 185 Water-cooled 5000×3000×2500 12000
8 DW-48/( 15~23 )-( 21~29 ) Hydrogen 2642~4500 2. 1~2.9 55 Water-cooled 4000×2700×2300 6000
9 D-0.57/16-200 Hydrogen 500 20 75 Water-cooled 5800×3200×2350 9000
10 ZW-0. 18/15-22 Hydrogen 150 2.2 11 Water-cooled 2200×1600×1700 2000
11 ZW-0.82/(6~8)-20 Hydrogen 300 2.0 22 Water-cooled 2500×1500×1750 2000
12 W-3/0.1-150 Hydrogen 212 15 55 Water-cooled 6000×2700×2100 15000
13 MW-7.7/9.8-40 Hydrogen 4200 4.0 355 Water-cooled 7500×3600×2000 22000
14 MW-25.2/(1.5~1.7)-10 Hydrogen 3300 1.0 315 Water-cooled 8000×3000×2200 20000
15 PW-0.6/(10~15)-30 Hydrogen 0~560 3.0 30 Mixed cooling 2200×1800×1600 1800
16 PW-13.7/17-25 Hydrogen 820 2.5 30 Mixed cooling 4000×2700×2300 6000
17 D-0.26/(28~31)-150 Hydrogen 400 15 45 Mixed cooling 3800×3200×1950 4800
18 PW-13.7/17-25 Hydrogen 820 2.5 30 Mixed cooling 4000×2700×2300 6000
19 VW-14.3/7 Hydrogen 750 0.7 110 Mixed cooling 4800×2250×2100 8000
20 DW-7.6/(4~5.7)-6.5 Hydrogen 2000 0.65 55 Mixed cooling 3500×3000×2300 6000


Project Case


Ukraine Project Alibek oilfield in Southern Kazakhstan Ningxia Zhongneng new materials engineering
Alibek oilfield in Southern Kazakhstan Zaozhuang CNG compressor project of Chengdu Shenliang Technology Co., Ltd. Beijing Hongke Qingneng Technology Co., Ltd. associated gas compressor for Shanxi Yan'an 60000 m3 project


FAQ


What applications is the DW-3.8/(4~6)-14 Nitrogen Compressor suitable for?

It is ideal for chemical fertilizer production (nitrogen compression in synthesis processes), petrochemical industry (pipeline purging and equipment pressure testing), and metal processing (inert atmosphere protection during heat treatment). Its partial oil-free lubrication design (oil-free in cylinders and packing) ensures nitrogen purity, making it particularly suitable for scenarios requiring clean nitrogen, such as pharmaceutical industry inerting and food processing fresh-keeping.


Can the compressor be customized for specific needs?

Yes. The manufacturer provides tailored solutions based on customer requirements, including adjustments to treatment capacity, inlet/outlet pressure, and ambient adaptability. Customizations cover cooling system optimizations (e.g., adjusting cooling water circulation volume for extreme temperatures), explosion-proof grade enhancements (to meet higher-risk environment standards), and auxiliary equipment configurations (e.g., adding specialized filters or pressure stabilizing devices).


How often does the compressor require maintenance?

Benefiting from its durable component design and optimized lubrication system, the compressor has extended maintenance intervals. Routine inspections (e.g., checking lubricating oil pressure, cooling water flow, and instrument readings) are recommended monthly. For key components, vulnerable parts (such as piston rings, guide rings, and packing) typically need replacement every 8,000 hours of operation, while major overhauls (involving crankshaft, connecting rod, and cylinder inspection) are generally required every 30,000 hours, depending on actual operating conditions.


Telephone

+86 13955206799

Landline

+86-552-4190082

Address

No. 66 Jinhe Road, Huaiyuan Economic Development Zone, Bengbu City

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