BIZOMAT MAKEOS · Pneumatics
Air Receiver Size
What receiver volume covers this demand above compressor supply for this time and pressure band?
Receiver volume needed to supply an air deficit (demand above compressor output) for a given time while the pressure falls between two limits, and the time a chosen receiver lasts.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Air demand above compressor supply | m³/min free air | Demand (as free air) that exceeds what the compressors can deliver during the event. |
| Duration of the deficit | min | How long the deficit lasts. |
| Starting pressure (gauge) | bar | Receiver pressure at the start of the event (compressor cut-out pressure). |
| Minimum allowed pressure (gauge) | bar | Lowest pressure at which users still work. |
| Receiver volume to check (0 = none) | m³ | Volume of an existing or proposed receiver (m³; 1 m³ = 1000 L). |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Air demand above compressor supply
- What it is
- How much more air the users demand than the compressors can supply during the event, expressed as free air per minute.
- Units and format
- Enter a number in m³/min free air: m³/min free air. The form accepts 0.000001 m³/min free air to 100000 m³/min free air. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2 m³/min free air as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Required receiver volume rises in direct proportion.
- Get it right
- Enter only the excess demand above compressor output, not the total demand.
What this means: Duration of the deficit
- What it is
- How long the demand above compressor supply lasts, from the event start to when demand drops or a standby compressor takes over.
- Units and format
- Enter a number in min: minutes. The form accepts 0.000001 min to 100000 min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1 min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Required receiver volume rises in direct proportion.
- Get it right
- Enter minutes, not seconds.
What this means: Starting pressure (gauge)
- What it is
- The receiver pressure when the deficit begins, usually the compressor cut-out or load pressure.
- Units and format
- Enter a number in bar: bar (1 bar = 100 kPa). The form accepts 0.000001 bar to 1000 bar. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 8 bar as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A higher starting pressure widens the band and reduces the volume needed.
- Get it right
- Enter gauge pressure; it must be above the minimum allowed pressure.
What this means: Minimum allowed pressure (gauge)
- What it is
- The lowest receiver pressure at which the air users still work correctly.
- Units and format
- Enter a number in bar: bar (1 bar = 100 kPa). The form accepts 0 bar to 1000 bar. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 6.5 bar as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A lower minimum widens the band and reduces the volume needed.
- Get it right
- Allow for pressure drop between the receiver and the users.
What this means: Receiver volume to check (0 = none)
- What it is
- The internal volume of an existing or proposed receiver, to check how long it covers the deficit.
- Units and format
- Enter a number in m³: cubic metres. The form accepts 0 m³ to 100000 m³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2 m³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A larger receiver covers the deficit for longer.
- Get it right
- 0 means no check. Enter cubic metres: one thousand litres is one cubic metre.
Method and formulas
- V = t × Q_deficit × p_atm ÷ (p₁ − p₂) (isothermal, pressures in bar).
- Time covered = V (p₁ − p₂) ÷ (p_atm × Q_deficit).
- Example: a 2 m³/min deficit for 1 min with 8→6.5 bar needs 1.351 m³.
Limitations
- Isothermal draw-down; a fast draw-down cools the air and gives slightly less.
- Pipework volume adds a little storage not counted here.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Size a receiver for a peak demand
- Reduce compressor cycling
- Check how long a receiver covers a compressor trip
Who it is for
- Maintenance engineers
- Energy and utilities managers
- Design engineers
What you get
- Required receiver volume
- Time an actual receiver can cover
- Air stored in the pressure band
Interpreting the result
- Receivers are pressure vessels and must comply with your pressure equipment regulations.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3032–3041. Topic reference; no source tables or recommended settings are reproduced.
Learn the Concepts Behind This Tool
These BIZOMAT Library readings explain the method this tool uses, with worked examples.
Method explained here · BIZOMAT original book
Supply clean, dry air at the right pressure
What it covers: Trace pressure drop from compressor to machine, fix the restrictions before raising pressure, size a receiver for peak demand, and dry, filter and drain the air so valves and cylinders keep working.
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