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  • Comparison between Screw Compressor and Scroll Compressor

    Working principle difference

    screw Compressor relies on a pair of intermeshing Yin and Yang rotor to rotate, and realizes gas compression through continuous volume reduction; While scroll compressor uses a fixed vortex plate and a revolution around it (without rotation) the dynamic vortex disk forms multiple closed crescent-shaped chambers, and the volume is gradually reduced with the movement to complete compression.

    Performance and applicable scenarios

    screw Compressor is suitable for medium and large industrial systems (such as refrigeration station and air compressor station), with high reliability, wide load adjustment range and long-term continuous operation capability; Scroll compressor has small volume, low vibration and low noise, it is widely used in commercial air conditioners, heat pumps, small water chiller and other occasions with high requirements on mute and compactness.

    Energy efficiency and maintenance

    • energy efficiency performance:modern variable frequency scroll compressor has excellent efficiency under partial load; Screw compressor has high Full load efficiency, and the two-stage/injection cooling technology further improves the comprehensive energy efficiency.
    • Maintenance requirements:the screw structure is complex, and lubricating oil and oil filter need to be replaced regularly; Scroll moving parts are few, no vulnerable valve plate, longer maintenance period and lower cost.

    Selection suggestions

    system size, load characteristics, space constraints, and O & M conditions should be considered when selecting. For example: 50–500 kW cooling capacity projects often adopt vortex parallel scheme; Super 300 kW or when the low temperature condition of-40℃ is required, the screw compressor is more adaptable.

    Screw Compressor
    double rotor structure

    Scroll Compressor
    dynamic and static vortex plate engagement

    Schematic diagram of core structure of screw and scroll compressor (SVG diagram)

  • Gas Supply No Less than 0.2M ³ @ 0.3MPa/Min: Specification Writing and Technical Meaning Analysis

    What is “the gas supply is not less than 0. 2m³ @ 0.3MPa /min ”?

    This parameter is the key performance index of compressed air system or pneumatic equipment, indicating that the pressure is0.3 MPa (MPa)stable output air volume per unit timeno less than 0.2 cubic meters (m³), the time unit isper minute (min).

    Standard writing forms description

    it is recommended to adopt internationally accepted and unambiguous engineering expressions:

    • numerical unit working condition, use the @ symbol to connect pressure conditions (industry practice, non-mathematical multiplication sign);
    • unified use of pressure unitsMPa(Instead of kgf/cm² or bar), avoid conversion errors;
    • for unit volumem³, Time Unitmin, slash “/” cannot be omitted;
    • “Not less than” should be explicitly written≥0.2 m³/min @ 0.3 MPa(More in line with technical documentation specifications).

    Common miswriting and precautions

    ❌Error example:
    •” 0.2m3/min @ 0.3mpa “(Case is not standard, space is missing, unit abbreviation is incorrect)
    • 0.2 cubic meters/minute @ 0.3 MPa (mixed Chinese and symbols, not applicable to the technical tender)
    ✅Correct example:
    ≥0.2 m³/min @ 0.3 MPa

    0.3 MPa

    ≥0.2 m³/min
    airflow direction →

  • How Much Pressure Does the High Barrier Pesticide Bottle Need When Blowing? Process Parameter Analysis

    What is a high barrier pesticide bottle?

    High barrier pesticide bottles are usually made of multi-layer co-extrusion (such as PE/EVOH/PE) or pet material coated with silicon oxide, which aims to block moisture, oxygen and volatile components of pesticides and ensure the stability and storage safety of pesticides.

    Key role of blowing pressure

    in the process of blow molding, “blowing” means injecting compressed air into the premolded blank (parison) to shape its inner wall laminated mold. The pressure of this link directly affects the uniformity of bottle wall thickness, the integrity of barrier layer and the sealing performance of bottle mouth.

    Typical blowing pressure range

    • general scope:0.8–1.6 MPa (About 8- 16 bar), depending on the bottle type, capacity and material structure;
    • high barrier multi-layer bottle:due to the strong rigidity of barrier layers such as EVOH and low melt strength, more precise control is often needed-recommended initial pressure 1. 0–1.3 MPa, supplemented by segmented supercharging (such as low-voltage charging first, then medium-pressure setting);
    • note:too high pressure will easily lead to barrier layer offset, interlayer stripping or bottle bottom thinning; If it is too low, the molding is insufficient, which will affect barrier performance and dimensional accuracy.

    Supporting process suggestions

    in addition to the main blowing pressure, the pre-blowing pressure needs to be optimized cooperatively (0.2–0.4 MPa), blowing time (1.5-4.0 seconds), Mold temperature (10–25℃) and cooling rate to ensure that the high barrier structure does not undergo phase separation or stress cracking during molding.

    Schematic of high barrier structure (EVOH layer centered)
    → blowing direction

  • Piston Compressor Recommended by Domestic Manufacturers | Industrial-Grade Reliable Model Selection Guide

    Overview of mainstream domestic piston compressor manufacturers

    as a traditional high-efficiency positive displacement gas booster compressor, piston compressor is widely used in chemical industry, refrigeration, air separation, mining, energy and other fields. A group of manufacturing enterprises with mature technology, complete qualification and perfect service have been formed in China, covering small and medium-sized general-purpose models to high-pressure special models.

    Representative manufacturer type

    • backbone enterprises of state-owned enterprises: for example, the compressor units under Shenyang Blower Group (Shen gu) and Shaanxi Blower (Shaanxi drum) have large project integration capabilities and military-level quality control;
    • professional manufacturer: Zhejiang Ningbo Oaks, Jiangsu Nantong Hengli, Shandong Weifang Fuyuan and other companies focus on the research and development of medium and low voltage piston machines, with high cost performance and fast after-sales response;
    • manufacturers in special fields: Chengdu Yingge and Shanghai Hanzhong precision machine have independent patented technology in terms of oil-free/low-oil Piston Machines for CNG filling stations and refrigeration systems.

    Selection and purchase suggestions

    we recommend that you pay attention to the following items:GB/T 10893-2023 standard compliance of general reciprocating piston air compressor, energy efficiency level (IE3 and above are preferred), material certification of key components (crankshaft, piston ring, air valve), and whether customized pressure/exhaust/explosion-proof configuration support is provided. We do not recommend that you use low prices as the sole basis for judgment.

    Structural diagram of piston compressor (schematic: cylinder, piston, connecting rod, crankshaft)

    Made in China · stable and reliable

  • Micro-Oil Air Compressor – What Is It in English?

    What Is a Micro-Oil Air Compressor?

    A micro-oil air compressor (also called “micro-oil lubricated air compressor”) is a compact, energy-efficient compressed air system that uses a minimal, precisely controlled amount of oil for lubrication, sealing and cooling-typically less than 1 ppm oil carryover in the output air. Unlike traditional oil-flooded compressors, it employs advanced rotor coating and optimized oil injection to achieve near-oil-free performance while retaining reliability and efficiency.

    Key Features

    • Ultra-low oil consumption (micro-dosing technology)
    • High air purity (meets ISO 8573-1 Class 2 or better)
    • Compact footprint and low noise design
    • Reduced maintenance intervals vs. standard oil-flooded units
    • Ideal for light industrial, laboratory, dental, and precision manufacturing applications

    Why Use ‘Micro-Oil’ Instead of ‘Oil-Free ‘?

    While oil-free compressors eliminate oil entirely, micro-oil models strike a practical balance: they deliver cleaner air than conventional oil-lubricated units-and often at lower cost and higher durability-without requiring expensive dryers or complex filtration systems typical of true oil-free solutions.

    Rotor

    Micro-oil injection point

    Clean Air Outlet

  • Shanghai Imported Air Compressor Related Information

    Overview of Shanghai imported air compressor market

    as an important economic and trade center in China, Shanghai is one of the principal repository of imported air compressor. High-end air compressor brands in Germany, Italy, Japan, Sweden and other countries (such as Atlas Copco, Kaeser, Sullair, Ingersoll Rand) are generally passed through Shanghai Free Trade Zone, waigaoqiao Free Trade Zone and local authorized distributors enter the domestic market.

    Major import channels and compliance requirements

    imported air compressor shall comply with China’s “special equipment safety law” and GB/T 13277-2023 “compressed air system energy saving design code” and other standards. Customs declaration, certificate of origin, CE /UKCA certification (EU/UK), energy efficiency labeling filing and pressure vessel manufacturing license (if applicable). Some models also need to pass the type test of the National compressor refrigeration equipment quality supervision and inspection center.

    Common Application scenarios

    • automobile manufacturing and parts assembly line (high clean, constant pressure gas supply)
    • bio-medicine and electronic cleaning workshop (no oil, low vibration)
    • ship maintenance and port industry (salt spray prevention, high protection level)
    • data Center Cooling system supporting (frequency conversion energy saving, intelligent joint control)

    selection and service suggestions

    it is recommended that users choose brands with local technical service centers in Shanghai first, focusing on:energy efficiency level (first class energy efficiency is preferred),after-sales service response time (such as 4-hour arrival commitment)andfull life cycle cost (TCO) analysis capability. At the same time, compliance suppliers can be selected through Shanghai mechanical and electrical equipment Bidding Center or “Shanghai International Trade single window” platform.

    Core structure of imported air compressor (including intake filter, main engine, oil-gas separation and cooling system)

    → intelligent control system interface

    Figure: typical imported Screw Air Compressor key module layout (SVG vector schematic)

  • Calculating Power According to Pressure and Flow: Principle and Formula of Fluid System Power Estimation

    Why do you need to calculate power based on pressure and flow?

    In the design and energy efficiency evaluation of fluid machinery such as pumps, fans and hydraulic systems, the rapid estimation of input power is very important. This calculation does not depend on the nameplate or measured data of the motor, but is based on the basic physical principle of fluid work.

    Core calculation formula

    under ideal working conditions (ignoring efficiency loss), the shaft power required by the fluid system (unit: Watt) can be estimated by the following formula:

    • power P = Δp×q(International System of Units)
    • where:Δpfor pressure difference (Pa, N/m²),Qvolume flow (m³/s)

    if you use a common unit of the project: P (kW) ≈ Δp (bar) × Q (L/min) ÷ 600 — this is an approximate conversion (assume 1 bar = 10… Pa, 1 L/min = 1.667 × 10.. m³/s).

    Efficiency should be considered in Practical application

    due to mechanical, volume and hydraulic losses, the actual driving power shall be:

    Pactual= (Δp × Q) / η, where N is system gross efficiency (usually 0.5-0.85, depending on equipment type and working condition).

    Pump

    Q (m³/s)

    Δp = p₂ − p₁

    Output stream

    Schematic of power transmission in fluid system: pressure difference Δp and flow Q jointly determine theoretical power

    precautions

    • the formula is applicable to steady-state and incompressible fluids (such as water and oil); The influence of compressibility and temperature change should be considered for gases.
    • Pressure units must be unified (recommended for full use Pa and m³/s)
    • this method provides a theoretical lower limit, and the safety margin must be superimposed during selection (usually +10% ~ 20%)

  • Does Oil Free Air Compressor Need Drainage?

    Oil Free air compressor although lubricating oil is not used to participate in the compression chamber workregular drainage is still required.. This is because during the compression process, the water vapor in the ambient air will condense into liquid water in the cooling stage and accumulate at the low point of the gas storage tank, condensate separator and pipeline.

    Why does condensate produce?

    No matter whether it is oily or not, as long as the air is compressed and cooled, it will follow the principle of “dew point”-high temperature and high humidity air will be compressed and heated, and then cooled by the aftercooler, the relative humidity quickly reaches 100%, and the excess water condenses into liquid water.

    What are the risks caused by undrained water?

    • Accelerated gas tank inner wall corrosion (especially carbon steel tank)
    • cause damage to internal water accumulation of pneumatic tools, valves or precision equipment
    • breeding microorganisms and polluting gas sources (especially for medical, food and electronics industries)
    • reduce system pressure stability and gas quality

    how to drain water scientifically?

    It is recommended to manually open the drain valve at the bottom of the air storage tank and drain it once a day. If it is equipped with automatic drainer (such as floating ball type or electronic timing type), the operation reliability and the smoothness of the drain outlet should be checked regularly. In high humidity environment, the drainage frequency needs to be increased accordingly.

    Condensate accumulation area gas tank

  • Oil Cooler Professional English Nouns

    Summary of common oil cooler professional English terms

    in the field of hydraulic system, engine cooling and industrial lubrication, accurate understanding of English terms related to oil cooler is crucial to reading technical documents, equipment selection and international cooperation. The following are high-frequency and standardized professional terms:

    • Oil Cooler: oil cooler (general term, refers to all heat exchange devices used to cool lubricating oil or hydraulic oil)
    • Shell-and-Tube Oil Cooler: Tube shell type oil cooler
    • Plate-Type Oil Cooler: plate type oil cooler
    • Air-Cooled Oil Cooler: air-cooled oil cooler
    • Water-Cooled Oil Cooler: Water-cooled oil cooler
    • Oil Inlet/Outlet Port: oil inlet/oil outlet
    • Heat Transfer Coefficient: heat transfer coefficient
    • Pressure Drop: Pressure Drop
    • Maximum Allowable Working Pressure (MAWP): maximum allowable working pressure
    • Thermostatic Valve: thermostatic control valve (used to adjust bypass oil flow)

    note: ASME, ISO 4413 or DIN 20023 and other standards check Terms Glossary and performance parameters.

    Oil Cooler Schematic

    Oil In

    Oil Out

    Core

    Illustration: typical oil cooler structure diagram (SVG vector diagram)

  • How Big Is the Gas Flow in Industry

    Typical range of industrial gas flow

    the gas flow in industry varies greatly due to application scenarios and cannot be summarized by a single value. For example, gas chromatograph carrier gas flow in a small laboratory is usually1-100 mL/min; And the main air compression flow of large air separation unit (oxygen/nitrogen) can reach10 ”-10” m³/h(Standard status). Common industrial processes such as combustion control, chemical reaction feed, flue gas desulfurization, etc., more than flow-rate range10-10⁴ Nm³/h(Standard cubic meters per hour).

    Key factors affecting traffic size

    • process Type: large processes such as synthetic ammonia and ethylene cracking are much higher than nitrogen purging for food packaging.
    • Equipment scale: the difference between a single reactor and a complete set of integrated unit is 3-6 orders of magnitude.
    • Gas properties and states: it needs to be converted to the standard state (0°C, 101.325 kPa) conduct comparability assessment
    • measurement reference: Volume flow (Nm ³/h), mass flow (kg/h) or molar flow (kmol/h) must be clearly marked

    practical Reference Chart

    the following figure shows the gas flow in typical industrial scenarios (standard conditions):

    Logarithmic scale illustration of industrial gas flow

    GC carrier gas
    ~0.001 Nm³/h

    Boiler combustion air
    ~10²-10³ Nm³/h

    Air separation main air flow
    ~10⁵ Nm³/h

    Large refining total exhaust
    >10⁶ Nm³/h

    The actual selection should be combined with process design documents, instrument range and precision requirements, and comply with ISO 5167, GB/T 21446 and other standards and specifications.