Proportional Flow Control Valve

Proportional Flow Control Valve — Precision Flow for Gas, Water & Oil

Proportional Flow Control Valve — Precision Flow for Gas, Water & Oil
A proportional flow control valve regulates the flow rate of gas or liquid in proportion to an electrical input signal (0-10V, 4-20mA, or RS485 Modbus). KaoLu manufactures two complementary technologies in Taiwan: stepper-motor driven needle valves (FC series) for ultra-fine, high-turndown control of air, water, and oil — and proportional solenoid valves (KLPV series) for fast, compact gas control in medical and analytical equipment.
With resolution down to 20 mL/min, repeatability of 0.1% F.S., hysteresis below 2%, and flow ranges up to 5000 L/min, our valves serve laser cutting, medical ventilators, gas blending, dosing, and semiconductor processes in 40+ countries.

What Is a Proportional Flow Control Valve?
Unlike an on/off solenoid valve, a proportional flow valve continuously adjusts its orifice to deliver exactly the flow your process demands. Common synonyms include electronic flow control valve (EFC), electronic flow regulator, motorized needle valve, and proportional solenoid valve — different names, same principle: electrical signal in, precise flow out.

Stepper-Motor Driven Needle Valve (FC Series)
An ultra-fine threaded needle driven by a stepper motor — smooth, proportional, accurate, and holds position with high torque even when powered off.
Resolution: 20 mL/min | Hysteresis: < 2% | Repeatability: 0.1% F.S.
Media: air, N2, O2, water, oil — stainless steel wetted parts available
Life: 10 million cycles (FC120 series, full-open to full-close)
Dosing capability: dispense as low as 1 mL of water
Best for: dosing, laser cutting assist gas, gas blending, liquid flow control

Proportional Solenoid Valve (KLPV Series)
Current-to-flow conversion with fast response and compact size, manifold-mountable, PWM tunable.
Flow ranges: 0-32, 0-140, 0-310 L/min | Working pressure up to 20 barg
Best for: medical ventilators, anesthesia machines, nebulizers, gas blending

Choose Your Flow Range
Series Max Flow @ 87 psig Turndown Signal Best For
FC-10 18 L/min high 0-10V / 4-20mA / RS485 Micro-dosing (1 mL)
FC-20 65 L/min high same Dosing, lab equipment
FC-120 230 L/min high same Laser cutting, 10M cycles
FC-300 400 L/min high same Industrial gas control
FC-1500 3000 L/min @150psi 1:400 same High-flow processes
FC-3000 5000 L/min @145psi 1:400 same Maximum flow
KLPV-HP 310 L/min — PWM/analog Medical ventilators

Closed-Loop Flow Control Systems
Pair any FC valve with our KMF series MEMS mass flow meter for true closed-loop control:
Setpoint → PM Driver → FC Valve → Flow → KMF Flow Meter → Feedback
Closed-Loop Air Flow Controller(FC1500A + KMF1500):flow control precision to a new level
Mass Flow Controller、Dual Loop Pressure Controller(QKL-CLC)

Applications
Laser Cutting — assist gas flow control, fast response
Medical Ventilators & Anesthesia — KLPV supplied to global manufacturers
Dosing & Dispensing — down to 1 mL water dispensing
Gas Blending — multi-gas mixing ratios
Semiconductor & Analytical — clean gas micro-flow
AI Server Liquid Cooling — precision coolant flow

Why KaoLu
✅ 45 years electro-pneumatic manufacturing — Made in Taiwan
✅ 20 mL/min resolution | 0.1% F.S. repeatability | < 2% hysteresis
✅ Turndown ratio up to 1:400(FC1500/FC3000)
✅ 10-million-cycle valve life(FC120)
✅ Multi-media: air, gas, water, oil — stainless steel option
✅ Supplied to global medical ventilator manufacturers
✅ 2025 German Design Award | CE, SGS, RoHS

FAQ
Q1: What is the difference between a proportional flow control valve and a solenoid valve? A standard solenoid valve is on/off only. A proportional flow control valve continuously adjusts flow in proportion to an electrical signal — 0-10V, 4-20mA, or RS485 Modbus.

Q2: Can one valve control both liquid and gas? Yes. The FC series stepper-driven needle valve controls air, gas, water, and oil. Wetted parts can be customized to stainless steel.

Q3: What is the smallest flow it can control? FC series resolution is 20 mL/min, and the FC-10/FC-20 can dispense as little as 1 mL of water — suitable for precision dosing.

Q4: What is turndown ratio and why does it matter? Turndown ratio is max/min controllable flow. FC1500/FC3000 reach 1:400, meaning one valve covers both micro-flow and high-flow — fewer valves, simpler system.

Q5: How long does the valve last? The FC120 series is rated for 10 million full-open/full-close cycles.

Q6: Can I build a closed-loop flow system? Yes. Pair an FC valve with our KMF MEMS mass flow meter and PM driver for closed-loop control with feedback.

Q7: Is it suitable for medical devices? Yes. Our KLPV proportional solenoid valves are supplied to medical ventilator and anesthesia equipment manufacturers worldwide.

Q8: What signals are supported? 0-10V, 4-20mA, and RS485 Modbus RTU. KLPV series also supports PWM control.

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