API 618 Pulsation Dampener Bottle Sizing Calculator

Q: Why are pulsation dampener bottles required on reciprocating compressors?

The intermittent opening and closing of reciprocating valves generates high-energy pressure waves that travel at the speed of sound through connected piping. Without dampener bottles, acoustic resonance causes severe cyclical piping vibration, cyclic fatigue cracking of flanges, and inaccurate flow metering.

Q: How does an internal choke tube create an acoustic low-pass filter?

The combination of the large bottle volume (acoustic capacitance) and the restricted choke tube (acoustic inductance) forms a Helmholtz acoustic low-pass filter. Frequencies above the cutoff frequency are attenuated, smoothing the pulsating slug flow into a steady, non-destructive stream.

Q: What is the acceptable residual pressure pulsation level under API 618?

API 618 specifies that the residual peak-to-peak pulsation in the line piping beyond the pulsation suppression device must not exceed a calculated percentage, typically between 1.0% and 2.5% of the absolute line pressure.

Size suction and discharge pulsation dampener bottles and internal choke tubes per API 618 Design Approach 1 & 2 to suppress acoustic pressure pulsations and pipe vibration.

Compressor Cylinder Geometry

Cylinder Bore B (inches):

Piston Stroke S (inches):

Compressor Speed (RPM):

Bottle Service Location:

Gas Thermodynamics & Acoustic Filter

Line Pressure P (psia):

Gas Speed of Sound c (ft/s): Nat Gas ~ 1300-1450 ft/s

Choke Tube Inside Dia (in):

Choke Tube Length (inches):

Pulsation Bottle Design Sizing

API 618 Minimum Bottle Volume

-- cu ft

-- Liters internal volume

Volume Sizing Ratio

-- : 1

Bottle / Swept Vol

Helmholtz Cutoff Frequency

-- Hz

vs 1X running frequency

Cylinder Swept Displacement: -- cu in (-- L)

1X Running Frequency: -- Hz

Recommended Shell Diameter x Length: -- in OD x -- in L

Estimated Residual Pulsation: --% (API target < 2%)

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Frequently Asked Questions

Why are pulsation dampener bottles required on reciprocating compressors?

The intermittent opening and closing of reciprocating valves generates high-energy pressure waves that travel at the speed of sound through connected piping. Without dampener bottles, acoustic resonance causes severe cyclical piping vibration, cyclic fatigue cracking of flanges, and inaccurate flow metering.

How does an internal choke tube create an acoustic low-pass filter?

The combination of the large bottle volume (acoustic capacitance) and the restricted choke tube (acoustic inductance) forms a Helmholtz acoustic low-pass filter. Frequencies above the cutoff frequency are attenuated, smoothing the pulsating slug flow into a steady, non-destructive stream.

What is the acceptable residual pressure pulsation level under API 618?

API 618 specifies that the residual peak-to-peak pulsation in the line piping beyond the pulsation suppression device must not exceed a calculated percentage, typically between 1.0% and 2.5% of the absolute line pressure.