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Category: Haha

  • What Are API 618 and API 619

    API RP 618 and API RP 619: analysis of core differences

    API RP 618 (Recommended Practice for Reciprocating Compressors for Petroleum, Chemical, and Gas Industries) and API RP 619 (Recommended Practice for Rotary Type Positive-Displacement Compressors for Petroleum, Refining, and Related Industries) all are American Petroleum Institute (API) the recommended practice standards issued provide technical guidance for the design, selection, installation and maintenance of reciprocating and rotary volume compressors respectively.

    Key differences

    • different applicable models: API RP 618 focuses on reciprocating compressor (such as piston type), emphasizing pulse control, piping vibration analysis and valve reliability;
    • API RP 619facing rotary compressor (such as screw type, sliding plate type and Roots type), it focuses on rotor dynamics, bearing life, sealing system and lubrication management;
    • both are not mandatory regulations, but are widely adopted as engineering benchmark by global oil and gas and chemical projects.

    It is worth noting that, API RP 618 released Version 5 (RP 618-5) in 2023, while API RP 619 version 4 (RP 619-4) is still valid. The two together constitute API important pillar of compressor standard system.

    Reciprocating Compressor
    (API RP 618)

    Rotary compressor
    (API RP 619)

  • What Is the Power of 0.5 M³/Min Air Compressor? Common Models and Selection Reference

    In industrial and small manufacturing scenarios, 0.5 m³/min (I.e. 0.5 cubic meters of displacement per minute) belongs to the typical specification of small piston or scroll air compressor. Its supporting motor power is usually3 kW to 5.5 kWbetween, depending on the working pressure, energy efficiency level, cooling method and whether it is a frequency conversion model.

    Key factors affecting power

    • exhaust pressure: 0.7 MPa (7 bar) under normal working conditions, 4 kW motor is mostly used; If 1. 0 MPa, it may rise to 5. 5 kW.
    • Volumetric Efficiency and mechanical efficiency: the overall efficiency of high-quality brands can reach 65%- 75%, and inefficient models may need more power to compensate for losses.
    • Operating system: We recommend that you reserve 15%-20% power margin for continuous operation; You can select it according to the nominal value for intermittent use.

    Note: nominal 0.5 m³/min “Usually refersfree air flow (FAD), non-theoretical exhaust volume, when purchasing, the performance curve provided by the manufacturer shall prevail, rather than just the nameplate flow.

    Schematic diagram: 0.5 m³ /min typical power range of air compressor (3–5.5 kW) 3 kW
    4 kW
    5.5 kW

    warm tips: for actual selection, please combine the total gas consumption, pressure loss and future expansion requirements of gas equipment, and give priority to products certified by GB/T 13277 or ISO 8573. Long-term overload operation is not recommended to avoid shortening the service life or causing overheating protection shutdown.

  • Is the Frozen Compressed Air Dryer a Pressure Vessel?

    Frozen compressed air dryer (refrigerated air dryer for short) is an industrial equipment that reduces the dew point of compressed air and removes moisture through refrigeration cycle. Its core components include evaporator, condenser, compressor and heat exchanger, among which the heat exchange chamber in contact with compressed air usually operates under pressure.

    Is it a pressure vessel? The key depends on the design parameters.

    According to China’s “special equipment safety law” and TSG 21-2016 “safety technology supervision regulations for fixed pressure vessels”, it is necessary to judge whether the equipment belongs to pressure vessels and meet the following three conditions at the same time:

    • working pressure ≥ 0.1 MPa (Gauge pressure);
    • volume ≥ 25 L;
    • the medium is gas, liquefied gas or liquid with the highest working temperature higher than the standard boiling point..

    The design pressure of most medium and large refrigerated air dryer evaporators/gas-water separation Chambers is 0. 7–1.0 MPa, the volume usually exceeds 30 L, and the processing medium is compressed air (gas), socomply with the definition of pressure vessel. But small integrated refrigerated air dryer (such as rated throughput < 1 m³/min, cavity volume < 25 L) may be exempted from supervision.

    Actual regulatory requirements

    refrigerated air dryer of pressure vessels must be designed and manufactured by qualified design units (A2 or D pressure vessel manufacturing license), special equipment product quality certificate is attached to the factory, and the use registration and regular inspection are handled according to regulations.

    Evaporator (pressure chamber)

    Compressed air inlet

    Dry air outlet

    Note: The above figure shows refrigerated air dryer pressure-bearing core component-evaporator cavity (blue frame), which directly bears the pressure of compressed air system as the pressure boundary, which is the key part to determine whether it belongs to the pressure vessel.

  • 6kg Force: Unit of Comprehension and Its Application in Engineering and Daily Life

    What is 6kg force?

    “6kg Force” (kgf) is a non-International System of Units (SI) force unit, defined as the standard gravitational acceleration of an object with a mass of 1 kilogram (9.80665 m /S²). Therefore, 6kg force ≈ 6 × 9.80665 ≈58.84 Newton (N).

    Common Application scenarios

    • spring scale. Mechanical measuring tools such as torque wrench are often calibrated by kgf
    • description of kgf commonly used in Bolt pre-tightening force, door hinge load bearing and load bearing test of children’s toys
    • some Asian countries’ industrial codes still use kgf as the design reference unit.

    Conversion relationship with international units

    note: kgf is not a SI unit, and Newton (N) is recommended for modern engineering. Please confirm whether it is “force” instead of “quality” during conversion-for example,” 6kg “Is the quality,” 6kgf “is the force.

    6 kgf ≈ 58.84 N

    Equivalent tension under standard gravity

  • Shanghai Large Screw Air Compressor Agent

    Professional services for large Screw Air Compressor solutions in Shanghai and East China

    as an authorized agent in the field of compressed air in deep farming industry for many years, we provide customers in Shanghai and Yangtze River Delta with large double-screw air-compression system certified by the original factory, covering 160kW-630kW full series of models, supporting customized pressure, exhaust volume and intelligent joint control scheme.

    Core advantages

    • ✅Original direct supply: establish long-term agency cooperation with international first-line brands (such as Atlas Copco, Ingersoll Rand, Kaishan)
    • ✅Full Cycle support: including site survey, system design, installation and commissioning, preventive maintenance and quick response of spare parts
    • ✅Energy-saving upgrade service: provide energy efficiency audit and permanent magnet frequency conversion alternative solutions for air compressor stations to help customers reduce comprehensive energy consumption by more than 20%

    we adhere to the principle of “technology first and Service Implementation”. All engineers are certified and equipped with mobile servicer and remote diagnosis platform to ensure 7 × 24 hours emergency response. Please contact us for exclusive energy efficiency evaluation report and selection suggestions.

    Intake end
    Host Unit
    Exhaust end
    Structure of twin-screw air compressor

  • 0.6kg Unit of Compressed Air: Understand Common Misunderstandings in Pressure Units

    In the industrial pneumatic system, air compressor selection and equipment nameplate identification, the expression “0.6kg” is often seen, such as “working pressure: 0.6kg ‘. However, it needs to be clear:‘Kilometer’ itself is not a pressure unit., this is actually a shorthand for engineering habits, meaning0.6kg force per square centimeter (kgf/cm²), approximately equal0.059 MPa or 59 kPa.

    Why use ‘kilograms ‘to describe the pressure?

    Popular expression in the context of traditional engineering: 1 kgf/cm² ≈ 98.07 kPa, close to 0. 1 MPa to facilitate estimation. Therefore, ‘0.6kg ‘means 0.6 kgf/cm² ≈ 58.8 kPa, common in small pneumatic tools, packaging equipment and low pressure purging scenarios.

    Unit conversion reference

    • 0.6 kgf/cm² = 0.0588 MPa
    • 0.6 kgf/cm² ≈ 58.8 kPa
    • 0.6 kgf/cm² ≈ 8.5 psi (Pounds per square inch)
    • 0.6 kgf/cm² ≈ 0.58 bar

    note: Pascals are recommended in international standards (Pa) and its multiple (kPa, MPa), design documents and safety specifications should avoid using non-legal units such as ‘kilometer’ to prevent ambiguity or compliance risks.

    0.6 kgf/cm²
    ≈ 58.8 kPa | ≈ 0.059 MPa

    Pressure unit indication | Non-legal units need to be carefully converted