Flow control valves are essential for regulating the rate of fluid movement in hydraulic, pneumatic, and process systems. To properly interpret system drawings—such as P&ID diagrams, ISO hydraulic schematics, or pneumatic circuit layouts—it’s important to understand the symbol for flow control valve and its many variations. This guide explains key flow control valve symbols and how to recognize them in technical documentation.
What Is a Flow Control Valve?
A flow control valve (also known as a flow regulator or flow regulating valve) manages the speed of fluid flow within a system without altering pressure. These valves are used in applications like hydraulic machines, process control systems, and industrial automation.
There are many types, including:
- Fixed orifice flow control valves
- Adjustable flow control valves
- Pressure-compensated flow control valves
- One-way flow control valves (check + throttle combined)
Basic Flow Control Valve Symbol
The symbol for flow control valve typically consists of a restriction or orifice represented by a diagonal arrow across a line or within a square.
Standard symbol:
----->◄----The triangle or diagonal line suggests adjustable or variable flow control.
Common Flow Control Valve Symbols
1. Adjustable Flow Control Symbol
----->┤/◄----A diagonal or slanted line represents a variable flow restriction. Sometimes enclosed in a box, this indicates adjustability.
2. Flow Regulator Valve Symbol
Flow regulators often share the same symbol as flow control valves. They may include an arrow to indicate direction:
----->|◄----3. One-Way Flow Control Valve Symbol
This is a combination of a check valve and a flow control valve, allowing free flow in one direction and restricted flow in the other:
--->|<◄---This symbol shows an integrated function of throttling and reverse protection.
4. Hydraulic Flow Control Valve Symbol
In ISO 1219 hydraulic schematics, a flow control valve may appear as:
┌─────┐
| ─◄─ |
└─────┘Optionally with a spring, pressure compensator, or temperature compensator.
5. Pressure-Compensated Flow Control Valve Symbol
These symbols often include a spring and pressure balancing arrows or pilot lines:
┌─────┐
| ◄↔ |
└─────┘This shows the valve maintains a constant flow rate regardless of input pressure changes.
Flow Control Valve in P&ID
The flow control valve P&ID symbol often consists of:
- A restriction symbol
- A valve body with control lines (if applicable)
- Annotations like “FCV” (Flow Control Valve) or “FRV” (Flow Regulating Valve)
Example:
--->(FCV)---In some cases, a flow control element may be drawn inline with the process pipeline.
Related Terms and Keywords
- Symbol of flow control valve and flow control valve symbols are used in mechanical and process engineering literature.
- Flow control symbol is a broader term that may also refer to pneumatic or digital signal control.
- Flow regulating valve symbol and flow regulator valve symbol are used interchangeably with flow control valve terminology.
Conclusion
Understanding the correct flow control valve symbol—whether in a hydraulic diagram, P&ID, or pneumatic schematic—is essential for system design, operation, and troubleshooting. From adjustable regulators to pressure-compensated designs, each symbol provides clues to the valve’s function and behavior.
Need help interpreting flow control valve symbols or selecting the right component for your system? Contact us for technical support and reliable valve solutions.
