Frequently Asked Questions

Bottle Sizing Service - Level 2

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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 non-standard 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  
Distance between cylinder throws
Distance from cylinder to scrubber [3]  
Location of line-side nozzle (head or shell?)  
Diameter and seam-to-seam 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.