ASCO proportional valves are electro‑pneumatic components that control flow and pressure proportionally (modulated) using analog or digital input signals.
Core Functions
Pressure and flow proportional control
Fast and stable response
Low hysteresis and high accuracy
Integration with PLC / DCS systems
Benefits
Process stability
Energy optimization
Reduced product loss
High quality control
Long‑life field performance
Proportional valves can operate under two different control paradigms:
Open‑Loop (Open‑loop)
Produces output based on input signal
No feedback
Used in simple applications
Closed‑Loop (Closed‑loop)
Operates with sensor feedback
Compares Setpoint (SP) – Process Value (PV)
PID control provides high precision
👉 Closed‑loop control is preferred in industrial applications.
Proportional valves are often part of a PID control loop:
P (Proportional): Instantaneous error correction
I (Integral): Eliminates steady‑state error
D (Derivative): Improves system stability
👉 With correct PID tuning:
Overshoot decreases
Stability increases
Energy consumption decreases
🔹 Direct‑Acting Proportional Valves
Fast response
Low flow applications
Precise control
🔹 Pilot‑Operated Proportional Valves
High flow and pressure
Wider control range
🔹 Integrated Proportional Manifold Systems
Compact design
Multiple control points
🔹 Digital Proportional Drivers
PID integration
Precise adjustment and calibration
Data monitoring and diagnostics
🏷️ Example Series and Model References
ASCO Sentronic Series (electro‑proportional control)
ASCO 202 / 602 Series
ASCO proportional pressure control valve solutions
Proportional valve performance depends on flow characteristic:
🔹 Linear Characteristic
Flow increases linearly with input signal
Simple control applications
🔹 Equal Percentage
Precise control at low flow
Preferred in process applications
👉 Wrong characteristic selection can cause:
Control deviation
Unstable system
Energy loss
Valve performance is directly linked to the driver:
Signal Types
0–10 V analog
4–20 mA industrial standard
PWM high‑frequency control
Critical Parameters
Signal resolution
Response time
Noise immunity
👉 Appropriate driver selection = high control accuracy
| Parameter | Range / Value | Impact |
|---|---|---|
| Control Signal | 0–10 V / 4–20 mA / PWM | Signal compatibility |
| Response Time | 10 – 200 ms | Control accuracy |
| Flow Range | mL/min → high L/min | Application scope |
| Pressure Range | 0.1 – 350 bar | Industrial compatibility |
| Accuracy | ±0.5% – ±2% | Process safety |
| Hysteresis | Low | Stability |
| Material | Aluminum / Steel / Stainless | Chemical compatibility |
| Electrical Protection | IP65 / IP67 | Field durability |
| Certification | CE / ATEX / UL | Global compliance |
Correct proportional valve selection requires:
Flow and pressure requirements
Cv / Kv value
Control signal compatibility
System dynamics
Environmental conditions
Required control accuracy
👉 Engineering calculations and field data are critical.
| Failure | Result | Risk |
|---|---|---|
| Wrong valve type selection | Control failure | Critical |
| Signal incompatibility | Loss of accuracy | High |
| Particle contamination | Response degradation | High |
| Driver mismatch | Control error | High |
| Non‑certified product | Safety risk | Critical |
Proportional control → reduces unnecessary flow losses
PID optimization → minimizes energy consumption
Digital drivers → enable data analysis and optimization
Power plants
Petrochemical and chemical facilities
Food and pharmaceutical dosing systems
HVAC systems
Test and measurement equipment
OEM code / model
Control signal type
Flow and pressure range
Cv / Kv requirements
Environmental conditions
Electrical protection (IP)
Certification needs
What is a proportional valve? A valve that controls flow or pressure proportionally based on the input signal.
Why is PID control important? It ensures the system operates stably, quickly and precisely.
PWM or analog signal — which to choose? Depends on the application; analog signals are generally preferred for high precision.
How to choose the right valve? Through engineering analysis based on process conditions, flow, pressure and control requirements.
ASCO proportional valves: ✔ Provide precise pressure and flow control ✔ Improve process stability ✔ Optimize energy efficiency ✔ Fully integrate with automation systems
For your project:
Valve and driver selection
Sizing and engineering support
Certification consultancy
Logistics and integration support
📞 +90 505 696 61 00
🌐 www.yesilgrupenerji.com
Yeşil Grup Enerji is an independent supplier. Without official distributorship, our global sourcing network delivers solutions tailored to your projects.