Noise pollution as most people these days are aware of, is the production of unwanted sounds which render adverse effects on the tender ears and thus, pose potential hazards to health and communication. Considering the serious health hazards of noise pollution, many countries have introduced regulations to restrict the noise levels at workplace.
In hydraulic systems, generally,
hydraulic pump is the source of noise pollution which calls for special attention to combat the issue. Every hydraulic pump injects structure-borne and fluid-borne noise within the system and consequently renders air-borne noise out in the environment. Here, it is important to understand that fluid-borne noise is generated due to the vibration of components by pressure pulsations while structure-borne noise is the result of exciting vibrations within the interlinked components. The fluid and structure borne noises together infect the involved air mass thus, polluting the environment.
Following are few key solutions to three basic sources of hydraulic system's noise emission:
Fluid-borne noise
Fluid-borne noise in a hydraulic system can always be minimized through a better pump design but yet, it cannot be diluted completely. Installation of a silencer can prove helpful in controlling the pump noise. A simple reflection silencer diminishes the sound waves by superimposing another sound wave carrying same amplitude and frequency at a 180 degree phase angle to the original one.
Structure-borne noise
The trick to tackle structure-borne noise is to eliminate the sound bridges amongst power unit and tank and power unit and valves as the structure-borne noise is created due to the vibrations of power unit and its prime movers. Rubber mounting blocks and flexible
hoses as connections can come handy in this situation. Alternatively, introduction of an additional mass can also help in reducing the vibrations at bridging points.
Air-borne noise
Air-borne noise can be handled by mounting the pump inside the tank or constructing the hydraulic reservoir with a thicker plate can reduce the noise radiations. The simple scientific reason behind it is that the magnitude of noise radiations through a given object is directly proportional to its area and inversely proportionate to its mass hence, an increase in mass of an object or a reduction in its surface area can prove effective in controlling the noise radiations.
