Features of Level 1 and Level 2 Service

The following chart compares features of each service with a standard Pulsation Study.

Wood VDN Bottle Sizing Service Wood VDN Design
Study (API 618)

Level 1
Basic Sizing
Level 2
Mini Pulsation Study
Includes Mechanical Analysis (Note 1)
Risk Level See Note 2 Medium Risk Lower Risk Lowest Risk
Bottle Sizing Algorithms:
-      API 618, 5th Edition; API 11P
-      Wood VDN’s Sizing Technique
-      Acoustic model using Time Domain (MAPAK software)


Operating Conditions Evaluated Single condition per run Up to 20 Up to 1000
Filter Design, if required (including sizing of choke tube, baffles, etc.)  
Sizing of Orifice Plates  
(cylinder nozzle only)
Utilize Wood VDN’s extensive database of past projects  
Avoids any changes to bottle sizing
Allows packager to order material (without risk of size changing)
Calculate pressure pulsation and forces in bottles and cylinders  
Calculate Static AND Dynamic Pressure Drop in choke tubes and
orifice plates
Calculate Static AND Dynamic Pressure Drop in the piping system    
Calculate pressure pulsation and forces throughout the compressor package    
Detailed performance analysis of compressor package, including
pulsation effects
Minimize bottle costs (optimized design) to reduce capital cost for packager    
Mechanical analysis of piping, scrubbers, vessels to avoid resonance
(Design Approach 3 scope)
Turnaround Time for Bottle Size Recommendations Immediate 3 busness days 5-8 business days
for acoustical



Pulsation/Vibration Study per API 618 requirements. For more information, including our FREE primer on pulsation/vibration studies,
refer to www.BetaMachinery.com. For application assistance, call +1-403-245-5666.

Risk of inaccurately sized bottles:
    If pulsation bottles are sized too large, the risks are:
  • More difficult mounting and supporting requirements for large bottles.
  • Higher capital costs for material and fabrication of large bottles.

    If pulsation bottles are sized too small, the risks are:
  • Reliability concerns if there are excessive pulsations and vibrations.
  • Reduced performance and higher operating costs caused by excessive pressure drop.
  • Higher capital costs if secondary volumes are required.

In rare cases, a mini pulsation study is not adequate to properly size bottles. Instead, a full pulsation study is required.
This limitation could apply to specialty gas compositions and very high pressures.
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