The Level 2 bottle sizing requires some additional information beyond what is required
for a Level 1 bottle sizing. For a Level 1 bottle sizing, almost all the information
required can be found on the operating condition printouts. To see a comparison
between the required information for a Level 1 and Level 2 bottle sizing, see the
table below.
Information Required

Level 1
Bottle Sizing

Level 2
Bottle Sizing

Operating speed range (for capacity control)

✓

✓

Rated compressor or driver power (whichever is less)

✓

✓

Number of stages

✓

✓

Stroke length

✓

✓

Connecting rod length


✓

Rod diameter

✓

✓

Tail rod diameter (for tandem cylinder)


✓

Cylinder phasing


✓

Cylinder clearance (% of HE or CE swept volume)


✓

Unloaded valves?

✓

✓

Cylinder bore

✓

✓

Cylinder nozzle nominal pipe size
(or flow area for nonstandard nozzles)

✓

✓

Number of cylinders per bottle

✓

✓

Suction temperature at cylinder flange

✓

✓

Discharge temperature at cylinder flange

✓


Suction pressure at cylinder flange

✓

✓

Dischage pressure at cylinder flange

✓

✓

Ratio of specific heats^{ [1]}

✓


Compressibility ^{[1]}

✓


Gas composition ^{[2]}


✓

Specific gravity

✓


Dimensions



Distance between cylinder throws

✓

✓

Distance from cylinder to scrubber ^{[3]}


✓

Location of lineside nozzle (head or shell?)


✓

Diameter and seamtoseam length of scrubber ^{[4]}


✓

Distance from cylinder to skid ^{[5]}


✓

Cylinder nozzle length


✓

Gas passage diameters and lengths


✓

[1] Ratio of specific heats and compressibility can be calculated
from gas composition or from specific gravity (0.56 to 1.0).
[2] Gas analysis can be calculated from specific gravity (0.56 to 1.0) but there
is risk with this approach.
[3] Used to estimate choke tube length between suction bottle and scrubber.
[4] Used to estimate choke tube length and scrubber volume.
[5] Dimension used to estimate maximum overhung length of discharge bottle.