Oxygen, helium, compressed air, nitrogen, carbon monoxide, carbon dioxide, sulfur dioxide, hydrogen, argon, methane, steam are (among others) industrial fluids (gases and gas mixtures) used for many processes e.g. in the chemical sector, which sometimes also involve refrigerant vapours e.g. ammonia, R22.

Exhaust gases and more generally fumes related o combustions are also fluids present in the aerailic systems of many installations i.e. in the energy sector or in the case of heavy industries involving furnaces.

The production, the transport and the use of such industrial fluids are at the origin of phenomena accompanied by noise emissions e.g. related to the flow, to the processing by a valve, to the depressurisation (when it is not in connection simply with the transmission of noise emitted by other sound sources such as fans, motors, compressors, turbines), requiring the implementation of silencers.

Silencers for industrial fluids are noise-limiting equipment for pressurized fluid ducting networks and for air-flow networks, the principle of which depends on the intended application.

Silencer for pressurized industrial fluids

In the case of pressurized industrial fluids, the blow-off silencers i.e. the noise reduction devices installed at the downstream end for venting or the in-line silencers i.e. the soundproofing means inserted in the piping system, further upstream (in particular: just downstream of control valves) are devices (sometimes: multi-staged) in particular based on the presence of orifices through which the flow of gas is controlled.

In many cases, a dissipative part, i.e. a module involving a mechanism of sound attenuation along distance, completes (downstream) the efficiency of a silencer for industrial fluids.

It is not uncommon for a silencer for indsutrial fluids to be considered as a pressure vessel (what is in practice the case only in the event of a malfunction e.g. during the accidental obstruction of perforated internal parts which may be at the origin of gas retentions).

Such industrial silencers must then satisfy not only the performance requirements in terms of acoustics and fluid mechanics, which are very high - especially in terms of design - because of the complex functionalities generally expected, but they must also satisfy to those, for which there can be no question of deviation relating to the construction code adopted (in general selected by the client : CODAP, ASME or other), related to mechanical strength.

Silencer for industrial fluids for aeraulic networks

In the case of industrial fluids for aeraulic networks, absorption silencers (thus: with a lining with an absorbent material, the nature of which depends on the service conditions e.g. temperature, chemical composition of the gas, gas speed) are commonly used, both at the suction and at the discharge, being efficient in medium and high (but not: ultra-high) frequency.

However, reactive silencers also referred to as mufflers (based on the reflection of sound waves in relation to changes in the geometry of the frontal section in which an indsutrial fluid flows, sometimes: with several chambers) are often necessary for the exhaust of combustion engines to attenuate the low frequency noise.

In the case of fluids for aeraulic networks, for which taking into account the pressure does not imply any particular dimensioning in terms of mechanical strength, the performance in terms of insertion loss (which is an indicator of the decrease in noise) and in terms of total pressure loss (which is an indicator of aerodynamic performance) can sometimes result from attempts, for a silencer for industrial fluids, for technological compromises difficult to obtain due to some antagonisms inherent in the context.

The complexity of such situations reaches peaks when the lpressure drop of a silencer for industrial fluids impacts the efficiency of the installation in which its insertion is envisaged while the available space is limited.

A few tens of pascals more for the total pressure loss of the silencer (muffler) can result in a loss of earnings for the operator,all the more damaging it will exist throughout the life of the silencer, so for a period that can be counted in dozens of years (depending on the context, euros must be counted in tens of thousands, in hundreds of thousands if not in millions e.g. in the case of energy production facilities involving powers which can be counted in hundreds of megawatts).

ITS sells silencers for industrial fluids used in all processes: silencers for fans, for compressors, for thermal engines, for gas turbines, in-line silencers and blo-off silencers.

In many cases, ITS sizes these silencers for industrial fluids using computing resources (sometimes: developed in-house, such as the software SILDIS, which has several modules suitable for such simulations, either for the evaluation of the performance of these soundproofing devices, or for the preceding determination of the noise emitted by involved sound sources and of other related parameters).