A small hole muffler is a device that reduces noise by changing the spectral characteristics of jet noise. Its core principle is to replace the large nozzle with multiple small holes to transfer noise energy to high or ultra-high frequencies, thereby reducing the perceptible noise intensity to the human ear.

1、 Working principle

Spectral shift effect: The small hole muffler reduces the diameter of the small hole through which the airflow passes (usually ≤ 3mm), causing the peak frequency of jet noise to shift towards high or ultra-high frequencies.

Multi stage pressure reduction and impedance change: When gas passes through multiple layers of orifice plates, the pressure decreases step by step, the flow rate decreases, and the sound power decreases accordingly. Meanwhile, the reflection and interference of interfaces with different impedances further weaken the propagation of noise.

2、 Basic structure

Small hole mufflers are usually composed of straight pipes with closed ends, evenly distributed with small holes (diameter 1-3mm) on the pipe wall, and connected to the exhaust pipe through flanges or welding. In some designs, throttling and pressure reducing devices will be combined to form a composite noise reduction structure to enhance the noise reduction effect.

3、 Application scenarios

Industrial equipment exhaust noise reduction: mainly used for exhaust venting of high-pressure equipment such as boilers, compressors, and steam turbines, as well as noise control of safety valves and pressure relief valves.

Special Environmental Applicability: Suitable for high temperature, high humidity, or corrosive gas emission scenarios in industries such as petrochemicals, power, metallurgy, etc., such as exhaust pipelines in petrochemical enterprises and steam emission systems in power plants.

4、 Selection parameters

Need to provide exhaust volume, pipeline size, pressure, temperature, and medium type. For example, boiler exhaust mufflers are usually selected as anti spray resistance composite or all stainless steel small hole injection type.