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What are the different types of coaxial valves?

Oct 22,2025

Coaxial valves are primarily classified based on their actuation methods and structural functions. Different types are suited for various pressures, media, and control scenarios. At the core of their design lies the "coaxial alignment of valve core and valve body," enabling highly precise fluid control. Below is an analysis of the mainstream classifications and their applicable use cases:

I. Classified by Drive Type (the Core Classification Dimension):
1. Pneumatic Coaxial Valve:
● Principle: Powered by compressed air, the system drives a piston or diaphragm to move the valve core axially, enabling the valve to open, close, or adjust its flow.
● Features: Fast response time (typically 0.01–0.1 seconds), simple structure, low cost, and no risk of electric sparks.
● Applicable scenarios: Pneumatic control systems, automated production lines (e.g., food packaging, automotive welding), and flammable/explosive environments (such as chemical solvent transfer). Particularly suitable for medium- and low-pressure applications (≤10 MPa) and ambient-temperature media (gases, water, oils).

2. Electric Coaxial Valve:
● Principle: Driven by a motor (stepper motor/servo motor), the screw or gear precisely moves the valve core, enabling either on/off operation or proportional control.
● Features: High control precision (displacement accuracy up to 0.001mm), remote programmable control available, no compressed air source required—but response speed is slightly slower compared to pneumatic valves.
● Applicable scenarios: High-precision fluid control applications, such as medical devices (accurate drug delivery), semiconductor manufacturing (gas flow regulation), and laboratory instruments (reagent proportioning), suitable for low-to-mid pressure environments (≤16 MPa).

3. Hydraulic Coaxial Valve:
● Principle: Powered by hydraulic oil, the system uses a hydraulic cylinder to drive the valve core movement, delivering substantial output force and enabling control of large-diameter valves.
● Features: High load-bearing capacity (up to 50 MPa or higher), excellent resistance to contamination, making it ideal for high-load and harsh operating conditions.
● Application scenarios: Heavy-duty industrial hydraulic systems, such as construction machinery (excavator hydraulic circuits), metallurgical equipment (rolling mill hydraulic control), and marine hydraulic systems—suitable for high-pressure, high-viscosity media (hydraulic oil, heavy fuel oil).

II. Classified by Structural Function:
1. Straight-through Coaxial Valve:
● Structure: The medium flows in a straight line from the inlet to the outlet, with the valve core moving along the axial direction—there are no bends in the flow path.
● Features: Low flow resistance, high flow rate, minimal pressure loss—ideal for high-volume fluid transfer.
● Applicable scenarios: Pipeline transportation systems (such as tap water and industrial wastewater), HVAC air conditioning water systems—any scenario where reducing medium energy consumption is required.

2. Right-angle Coaxial Valve:
● Structure: The inlet and outlet are at a 90° right angle, with the valve core moving perpendicularly to the flow path axis, ensuring a compact installation space.
● Features: Suitable for compact installation environments, with slightly higher flow resistance compared to straight-through designs, yet offering superior sealing performance.
● Applicable scenarios: Internal hydraulic/pneumatic circuits within equipment (e.g., machine tool hydraulic stations), small instruments and meters (e.g., water circuit control systems in coffee machines), and compact, space-constrained integrated systems.

3. Proportional Coaxial Valve:
● Structure ●: Equipped with proportional solenoids or servo motors, the spool displacement is proportional to the input signal (current/voltage), enabling continuous adjustment of flow rate or pressure.
● Features: Non-"on/off" control, enabling dynamic flow adjustment with high precision.
● Applicable scenarios: Fields requiring precise adjustment, such as fuel injection in automotive engines, barrel temperature control in injection molding machines, and flow rate regulation in medical infusion pumps.

III. Classified by Sealing Method:
1. Soft-sealed Coaxial Valve:
● Seals: Made from rubber (nitrile rubber, fluoro rubber) or polytetrafluoroethylene (PTFE), offering excellent sealing performance and zero leakage.
● Features: Suitable for low-pressure, ambient-temperature media with mild corrosivity, but exhibits weaker resistance to high temperatures and abrasion.
● Applicable scenarios: Food and beverage industry (e.g., milk conveyance), water treatment systems (e.g., purified water pipelines)—applications requiring zero-leakage in hygienic environments.

2. Hard-sealed Coaxial Valve:
● Seals**: Made from metal materials (stainless steel, copper alloy), achieving tight sealing through precision grinding of the valve stem against the valve seat.
● Features**: Resistant to high temperatures (up to over 400°C), capable of withstanding high pressure, and highly wear-resistant, making it suitable for harsh operating conditions—but its sealing performance is slightly inferior to that of soft seals.
● Applicable scenarios: High-temperature steam systems (such as power plant steam pipelines), the metallurgical industry (for high-temperature molten slag transportation), and high-pressure oil and gas transmission pipelines.

Summary: Selection recommendations for different scenarios:

Demand Scenario	Recommended Valve Types	The underlying reason
Automated Production Line (Pneumatic Control)	Pneumatic Straight-Through Soft-Sealed Coaxial Valve	Quick response, low cost, and suitable for medium- and low-pressure ambient-temperature media.
Precise Delivery of Medical Medications	Electric Proportional Soft-Sealed Coaxial Valve	High control precision allows for precise adjustment of trace flow rates.
High-pressure hydraulic system (construction machinery)	Hydraulic Right-Angle Hard-Sealed Coaxial Valve	High-pressure resistant, anti-pollution, and suitable for compact installation spaces
High-temperature steam pipeline (power plant)	Manual / Pneumatic Hard-Sealed Coaxial Valve	High-temperature resistance and excellent wear resistance ensure long-term stable operation.

We can help you prepare a coaxial valve selection guide, listing the correspondence between "medium type, pressure range, and temperature requirements" and the "recommended valve types," making it easy for you to quickly match the right valve to your specific application. If you have any needs, feel free to send us a private message.