MINIMIZE THE EMISSION OF NOISE.
At the moment the society is very conscious with the acoustic pollution in the surroundings that surrounds it. And yet, the demand for machines and apparatus that produce a great noise pollution continues to increase. In the case of the generators sector, there is a decided commitment to the production of quieter solutions. Thus, the brands strive to incorporate in their catalogs soundproof generators, one of the great innovations in the sector. Do you want to know more about its operation and about which models of generators are quieter?
For some years the manufacturers of this type of equipment that produce this acoustic pollution, both small and large brands, are allocating much of their resources in investment in R & D & I to try to alleviate and reduce the acoustic effects of their Products, to adapt them to this new requirement of the market.
Given the nature of the generators, with rotating components, they are not exempt from this type of pollution, generating noises and vibrations that can be harmful to health. This sector has also been forced to invest much of its resources in its R & D & I departments to improve the design and manufacture of generating sets in order to reduce these emissions.
Let’s see what are the main components that generate noise in a generator during its implementation and operation and how to mitigate these emissions.
NOISE SOURCES GENSETS
The noise of generators is produced by six main sources:
- Engine noise: This is mainly caused by mechanical and combustion forces, and usually ranges from 100 dB (A) to 121 dB (A), measured at one meter and depending on the size of the engine.
- Cooling Fan Noise: Produced by moving air at high speed as it passes through the engine and radiator. The level varies from 100 dB (A) to 105 (A) dB at one meter.
- Alternator noise: This is caused by the friction of the cooling air and the brushes, and oscillates approximately between 80 dB (A) and 90 dB (A) to one meter.
- Inductive noise: This is caused by fluctuations in the current in the winding of the alternator that cause a mechanical noise that varies between 80 dB (A) and 90 dB (A) to a meter.
- Engine exhaust: Without an exhaust muffler, this ranges from 120 dB (A) to 130 dB (A) or more, but is normally reduced by at least 15 dB (A) with a standard muffler.
- Structural / mechanical noise: Mainly caused by the mechanical vibration of different parts and structural components that radiates as sound.
It must be taken into account that some characteristics of the generator set can influence the generation of noise and must be taken into account, the type of engine (gasoline or diesel), the number of revolutions and the type of cooling.
- Thus, a gasoline engine is quieter than a diesel engine.
- A spin speed of 1500 rpm is quieter than 3000 rpm.
- A water-cooled engine is quieter than air-cooled.
HOW TO REDUCE NOISE IN GENERATOR SET
The silent generators sets or soundproof generators sets are designed and manufactured with a series of special materials, which vary according to the manufacturer of the apparatus, which are responsible for absorbing the noise and prevent it from coming out, so that no Are both unpleasant and unhealthy.
In this sense, silent generators sets can emit a certain amount of noise, but this is always below the limit imposed by the World Health Organization (WHO), which is 70 dB (a) maximum allowed.
Even these silent devices are subjected to sound tests to verify that they are within the limits authorized by the institutions.
It should not be forgotten that frequent exposure to high amounts of noise can cause numerous health problems for people such as insomnia, fatigue, stress, impaired hearing, irritability, aggression, neurosis, depression, sleep disorders, reduction of memory, etc.
Regardless of the type of generator we need to reduce its sound attenuation, basically there are seven possibilities to reduce the noise of the generators: reduce the sound level of the source, acoustic barriers, sound insulation, insulation mounts, cooling air attenuation, Exhaust mufflers and efforts to maximize the distance between the generator set and the receiving source of this noise.
When generator sets are located outdoors, the use of cabinets (especially sound attenuator cabinets) combines all these strategies into one convenient package that provides weather protection and sound attenuation.
This strategy is the most used by the generators manufacturers since it allows a greater soundproofing and a greater standardization in the manufacture of the generating set.
COMPONENTS AND FACTORS ATTENUATING NOISE IN A GENERATOR
- Acoustic barriers: rigid materials with significant mass and stiffness reduce the transmission of sound. Examples include typical steel sheet of cabinets and walls with concrete or sand filled blocks or solid concrete walls typical of indoor generator room facilities. It is also important to eliminate sound leaks through cracks in doors or walls, or through access points for leaks, fuel or electrical wiring.
- Sound insulation: There are sound absorbing materials to cover the air ducts and to cover walls and ceilings. Directing noise towards a wall covered with sound absorbing material can be very effective. Installing materials that are resistant to oil and other engine contaminants is often the most common. Fiberglass or foam may be suitable, depending on factors such as cost, availability, density, fire resistance, abrasion resistance, aesthetics and ease of cleaning.
- Insulation Mounts: Vibrating equipment creates pressure (noise) waves in the surrounding air. Anything physically connected to a generator set can cause vibrations that will be transmitted to the building structure. These connection points include sliding supports, radiator air discharge ducts, exhaust pipes, refrigerant pipes, fuel connections and wiring ducts. Placing flexible joints in these connections effectively reduces noise transmission. Mounting a generator set on vibration isolators with springs effectively reduces the vibration and noise that are transmitted through the floor.
- Cooling air attenuation: Attenuation baffles at the air inlet and outlet can help reduce the noise produced by the cooling air as it travels through the engine and radiator. The noise caused by the movement of the cooling air is significant due to the required volume, about 20 cubic meters per second for a generator with a diesel engine of 50 liters. Alternatively, the radiator can be placed remotely on a ceiling, for example, to eliminate this source of noise or to direct it upwards away from people or the medians. In addition, causing air to flow through an elbow at 90 degrees in a conduit reduces high frequency noise.
- Maximize distance: When there are no reflective walls to increase the noise produced by the generator set, the noise level will decrease by approximately 6 dB (A) each time the distance is doubled. However, if the median wall is within the close range of a generator set, the noise level may not be predictable. A near field environment is any location within two times the largest dimension of the noise source (generator set).
- Exhaust Mufflers: Generator sets are almost always equipped with a muffler (muffler) to limit exhaust noise from the machine. Exhaust mufflers are available in a wide variety of classes, physical and material arrangements. Generally mufflers are grouped into those of camera type or spiral type devices. Chamber-type devices tend to be more effective, but spiral-type devices are more compact and can provide sufficient attenuation for numerous applications. Mufflers can be made from cold rolled steel or stainless steel. Stainless steel is the preferred material for outdoor use when corrosion is a problem. Mufflers are available in a number of different “degrees” of noise attenuation which are commonly called “industrial”, “residential” and “critical”.
Industrial mufflers reduce noise from 12 to 18 dB (A).
Residential mufflers reduce noise from 18 to 25 dB (A).
Critical mufflers reduce noise from 25 to 35 dB (A).
In general, the more effective a muffler to reduce exhaust noise the greater the level of restriction on the exhaust of the engine. In long exhaust systems, the same piping will provide some level of attenuation.
What is the quietest generator?
Practically, today all brands have a range of silent generators, so it is difficult to choose a model or brand as the quietest of all, since most of those that make up these ranges have a sound emission levels Very similar, since all the marks conform to the current legislation of each country.
It is advisable to check the exact quantity of decibels emitted by the device and compare it with other models in the market before buying a Soundproof Generator, to ensure that we are acquiring the most silent model of the available options.
However, it is necessary to take into account a series of maximum values depending on the final location of the device, which we must keep in mind when making a purchase. The following table shows approximate values to take into account, however it is advisable to consult the legislation in force in each country:
|Peak db(A)||Continuous db(A)|
|Suburban Silent or
|Urban near industry||67||57||62||52|
In this way, we will be able to acquire a soundproof generator set that emits very little noise, and conforms to the legal limits, without being uncomfortable to the ear, nor cause damages to our health, reason why will be a device suitable to be installed in places In which it is needed with greater tranquility, such as private homes, medical centers, hospitals or offices.
LOOKING FOR A GENERATOR SET SOUNDPROOFED?
In Tecnics Grupos Electrógenos, S.L. we have more than 50 years of experience in the sector, designing and manufacturing custom generator sets. We soundproof the generator according to your needs.