DAMPENERS
Figure 4. Representation of the diaphragm type dampener in the system.
This formula directly relates the volume of the dampener and the pressure relationship, taking into account the compressibility of the gas. Percent damping: Throughout this article, the term“ percent damping” refers to the percentage of the maximum pressure fluctuation remaining in the system. Therefore, 5 % damping means that the pressure fluctuation will be at most 5 % of the average system pressure. Example: Calculate the dampener volume to allow for a 5 % pressure fluctuation for a three-piston pump operating at 120 rpm with an average flow rate of 500 L / min.
Solution Steps:
Single Stroke Volume( V stroke):
Qort Lmin
Vstroke = ̇ = 500 /
� n 120 rpm
417. L
Choosing the K and f Coefficients: For a three-piston pump K = 0.06( from table 1).
For 5 % damping f = 0.16( from table 2). Dampener Volume( V d
):
V d
K V f
stroke
006 417.. � 156. L
016.
Comment: A pulsation dampener of approximately 2 liters would be appropriate for this system. In practical application, it may be useful to include a safety factor for possible deviations.
Effects of pulsations on energy efficiency
The stroking motion of a pump creates sudden changes in fluid velocity and pressure. These changes, in accordance with Bernoulli’ s principle, lead to a constant imbalance between kinetic and potential energy. Energy losses occur through the following mechanisms: Hydraulic Friction Losses- The interaction of a fluid with pipe walls results in friction loss proportional to the square of its velocity.
Pulsations create sudden fluctuations in fluid velocity, increasing turbulence, which in turn leads to additional energy consumption. Friction loss in a steady flow
h f f
L D
2 v 2 g
While calculating with the formula, the total energy loss increases because the v term is constantly changing in pulsating flow. Decreased pump efficiency- Pumps are designed to operate at a specific operating point( flow and pressure) for maximum
Table 1. K coefficient for pulsation dampeners Pump Type
Single Acting, Single Piston
Double Acting, Single Piston
K coefficient
0.63
0.25
Three Pistons 0.06
( 5)
Table 2. Factor f for pulsation dampeners Desired Damping Percentage(% ΔP) f( Approximate) Comment
1 % |
0.08 |
3 % |
0.12 |
5 % |
0.16 |
10 % |
0.22 |
15 % |
0.27 |
For very sensitive applications( laboratory, test systems). Almost no ripple is desired in the system.
Applications requiring high precision( chemical dosing, pharmaceutical industry).
A standard, balanced value for most industrial pumps, providing both efficiency and equipment protection.
It may be sufficient for systems with moderate vibration tolerance. It provides a balance between cost and efficiency.
Acceptable for systems with high vibration tolerance. Often used when lower cost solutions are sought.
36 Valve World December 2025 www. valve-world. net