How Do Pulsation Dampeners Work?

A pulsation dampener consists of a chamber containing a gas cushion (usually nitrogen). The pressure increase created by the pump pushes the liquid into the dampener, and the gas inside compresses, storing energy like a flexible buffer. When the pressure starts to drop, the compressed gas expands again and returns the stored energy to the system.

What is a Pulsation Dampener?

A pulsation dampener is equipment that dampens the pressure and flow fluctuations (pulsations) created by positive displacement pumps, ensuring a smoother and vibration-free flow.

Especially for:

  • Diaphragm metering pumps (API 675 applications)
  • Peristaltic pumps
  • Piston and plunger pumps
  • Twin screw / lobe pumps

It is used to reduce vibrations in the outlet line of pumps operating with strokes (beats).

Why Use It?

Problem

Reason

Benefits of the Dampener

Flow fluctuation

Stroke movement in the pump

Smooth & continuous flow

Pressure shocks (water hammer)

Sudden valve closure, stroke start

Reduces impact loads

Pipeline vibration

Irregular momentum transfer

Noise & vibration are reduced

Instrumentation error

Flow/pressure sensors fluctuate

Provides accurate measurement

Diaphragm & hose life shortening

Excessive stress

Extends maintenance time

Equipment fatigue

Pressure oscillations

Mechanical safety increases

➡ In other words, it protects both the system, the pump, and the instrumentation.

Structure (Main Components)

Pulsation dampeners basically include the following parts:

  • A pressure chamber (gas chamber) in the body
  • Gas compartment → usually nitrogen
  • Separator element → Diaphragm, bladder, or piston
  • Process fluid connection
  • Gas filling valve

There is a flexible surface between the gas and liquid → provides compressibility.

Working Principle

The positive displacement pump creates a pulse effect with each stroke:

  1. When the pump stroke pressure increases:
    • Liquid enters the dampener
    • Gas volume compresses → absorbs energy
  2. When the stroke pressure drops:
    • Compressed gas expands back
    • Transmits the liquid back to the line with the stored energy.

Since this is repeated quickly, the flow becomes almost continuous.

Types

Type

Advantage

Area of Use

Bladder (balloon)

High pulsation damping

Industry, oil & gas

Diaphragm separator

Corrosion resistant, hygienic

Food, medicine

Gasless types

Maintenance free

Small systems

Metal diaphragm

High pressure

Chemical processes

✔ Material selection is made according to the fluid chemistry (PTFE, EPDM, FKM, etc.)

Correct Positioning

  • As close as possible to the pump outlet
  • Close to the highest point on horizontal lines
  • Maintaining distance after vortices and elbows

API 675 & API 674 standards recommend a damper/control valve combination.

Sizing Criteria

  • Pump stroke volume and speed
  • Line pressure and pulsation percentage (5% – 10% target)
  • Fluid viscosity
  • Maximum working pressure
  • Heat, corrosion, and hardness requirements
  • Gas pre-charge pressure

The pre-charge pressure is generally set around 60-80% of the operating pressure.

Summary of Usage Benefits

Benefit

What Does It Provide?

Smoother flow

Quality & controlled process

Less vibration & noise

Comfort & safety

Pump & hose life increase

Maintenance cost decreases

Measurement equipment accuracy increases

SCADA & control improves

Energy saving

Efficiency increases