Classification Of Angle Seat Valves
An angle seat valve is mainly classified by actuator type, normal valve position, connection method, and body design. Common categories include normally closed, normally open, single-acting, double-acting, threaded, clamp, welded, and flanged types. These classifications describe how the valve operates and how it connects to the pipeline.
Main Types of Angle Seat Valves
A seat valve closes when a moving sealing component contacts a fixed valve seat. Angle-seat construction uses an angled flow path between the inlet and outlet.
The main operating types are:
- Normally Closed (NC): Opens when control air is applied.
- Normally Open (NO): Closes when control air is applied.
- Single-Acting: Uses compressed air and spring return.
- Double-Acting: Uses compressed air for opening and closing.
Types Based on Actuation
A pneumatic seat valve is classified according to its actuator movement and return mechanism.
Single-Acting Type
A single-acting actuator uses compressed air for one movement and a spring for the return movement.
It includes two common arrangements:
- Normally closed: the spring returns the valve to the closed position.
- Normally open: the spring returns the valve to the open position.
Double-Acting Type
A double-acting valve uses pneumatic pressure for both directions of movement.
Its main characteristics include:
- No spring-return mechanism.
- Air pressure controls valve opening.
- Air pressure controls valve closing.
- Both positions can be controlled through pneumatic signals.
Types Based on Connection
An angle seat valve can also be grouped according to its pipeline connection.
Common connection types include:
- Threaded: Connected through internal or external threads.
- Clamp: Uses ferrules and clamp assemblies.
- Welded: Joined directly to the pipeline.
- Flanged: Connected through bolted flanges.
Manual and Pneumatic Types
A manual angle seat valve is operated without a pneumatic actuator. Valve movement is controlled directly through a hand-operated mechanism.
Pneumatic versions use compressed air and are commonly divided into single-acting and double-acting configurations. The actuator type determines how the valve stem moves and whether a spring controls its return position.
Type Classification Table
| Classification | Type | Main Difference |
|---|---|---|
| Normal position | Normally closed | Closed without control air |
| Normal position | Normally open | Open without control air |
| Actuation | Single-acting | Air and spring return |
| Actuation | Double-acting | Air in both directions |
| Connection | Threaded | Pipe thread connection |
| Connection | Clamp | Clamp assembly connection |
| Connection | Welded | Permanent pipe joint |
| Connection | Flanged | Bolted flange connection |
A Simple Way to Identify the Type
Angle seat valve types can be identified through four questions:
- How is the valve actuated?
- What is its normal position?
- How does it connect to the pipeline?
- What body configuration does it use?
These categories distinguish the main forms of an angle seat valve while retaining the same basic seat-and-actuator operating principle.
