# Meter-out — Exhaust-flow control

> Source: https://rodlesspneumatic.com/resource-center/pneumatic-glossary/meter-out/
> Language: en-US
> Category: Valves & circuits

## Definition

Exhaust-flow control: Restricts air leaving an actuator. Preferred for stable control of many pneumatic cylinder loads. Read the applicable product data and technical standard before treating a catalog value as interchangeable.

## Key facts

- **Term:** Meter-out
- **Full form:** Exhaust-flow control
- **Selection effect:** Preferred for stable control of many pneumatic cylinder loads.

## Meter-out: definition and engineering context

Exhaust-flow control. Restricts air leaving an actuator.

The term belongs to the valves & circuits context. Its exact limits can depend on the cited standard, catalog convention, unit system, reference state, and component configuration.

## Why Meter-out affects pneumatic selection

Preferred for stable control of many pneumatic cylinder loads.

- Meter-in: Use selectively because overrunning loads can become unstable.
- Manifold: Confirm station pitch, electrical architecture, total flow, and expansion limits.
- Silencer: Backpressure can reduce cylinder speed and valve performance.
- 3/2 valve: Common for single-acting actuators and on/off air functions.

## How to evaluate Meter-out in a catalog or replacement project

Read the value together with its unit, test basis, operating pressure, temperature, circuit state, and manufacturer definition.

For replacement work, compare the complete datasheet and drawing. A matching abbreviation or nominal size does not by itself prove functional or dimensional interchangeability.

- Supply-flow control: Restricts air entering an actuator.
- Common valve or distribution base: Base that shares supply and exhaust or distributes ports among multiple stations.
- Pneumatic exhaust muffler: Porous or baffled element used to reduce exhaust noise.
- Three-port, two-position valve: Directional valve with three ports and two switching states.

## What to verify before selection

- Preferred for stable control of many pneumatic cylinder loads.
- Use selectively because overrunning loads can become unstable.
- Confirm station pitch, electrical architecture, total flow, and expansion limits.
- Backpressure can reduce cylinder speed and valve performance.

## Common mistakes

- Treating Meter-out as a universal definition without checking the manufacturer or standard context
- Mixing gauge and absolute values, incompatible units, or different reference conditions in one comparison
- Selecting a component from the term or nominal value alone without checking the complete operating point and drawing

## Frequently asked questions

### What does Meter-out mean in pneumatics?

Exhaust-flow control. Restricts air leaving an actuator.

### Why does Meter-out matter when selecting a component?

Preferred for stable control of many pneumatic cylinder loads.

### Can Meter-out values be compared directly between catalogs?

Only after the unit, reference condition, test method, operating point, and manufacturer definition have been reconciled.

## Technical references

- [ISO 5598:2020](https://www.iso.org/standard/67985.html): Provides the international fluid-power vocabulary used to interpret pneumatic terminology.
- [ISO 1219-1:2012](https://www.iso.org/standard/60184.html): Defines graphical symbols and circuit-documentation principles for fluid-power systems.