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Vent-Silencers

Noise is common when working with vents, what if that noise can be reduced to a minimum? We are working towards a quieter industrial environment;

Noise is common when working with vents, what if that noise can be reduced to a minimum? We are working towards a quieter industrial environment. With our vent silencers, you can experience a serene surrounding. Opening vents can cause noise up to 150-160 dB (A) and might cause hearing damage to the operator and noise pollution for the environment is inevitable. In addition, stringent limitations on noise production are imposed. Next to that, creating a safer work environment when using a quality and sustainable vent silencer.

 

Solving complex problems

Different demands require different specifications. With our extended experience, we can help solve your complex noise pollution problems by turning extreme demands into practical solutions. Our goal is to be leaders in our field; our success has been proven in the past 35 years. If you have the requirements Q.E.I. can help you with your custom made vent silencer.

Applicable regulations and design codes differ from one another. All our components are calculated and subjected to internal pressure. Construction and compliance are according to the applicable Pressure Vessel Code for the district or industry of your operations.

Q.E.I. developed a new vent silencer, the AFBR. Next to the AFB (75-90dB (A) at 1m free field 90°) and ERR (115+dB (A) at 1m free field 90°) the range of the AFBR completes the selection. The ideal silencer for the range between 85 – 115 dB (A), more compact than the AFB silencer. The AFBR silencer can be mounted on any vent, is easily installed and durable. Innovation never stops, QEI keeps on developing the silencers so you can enjoy the quietness.

 

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Diffusers

Control valves, frequently accompanied by high levels of noise generation, often achieve pressure reduction in gas or steam networks.

Control valves, frequently accompanied by high levels of noise generation, often achieve pressure reduction in gas or steam networks. Reducing pressure also reduces generated noise. We provide solutions like noise attenuating diffusers, located downstream from the control valve. Using this method the noise attenuating is compact and demands no maintenance.

 

Generated noise

Pressure in a gas stream can cause sudden velocity and pressure changes in a valve. Hereby generating sound power levels of 160 dB, which spread through the walls of the valve and the downstream piping. Influences of the noise level are:

  • System pressure
  • Pressure-drop
  • Gas velocity

A downstream diffuser reduces pressure drop across the valve and proportionally reduces the generated noise.

 

Noise attenuation in the diffuser

We achieve noise attenuation using the following steps:

  • Partially reflecting noise entering the diffusers, the proportions determine this effect
  • The production of small gas jets is forced by openings in the diffuser, which mutually interfere and attenuate the noise
  • Altering the noise spectrum; low frequency noise transforms into higher frequencies that are more efficiently impeded in the pipe wall

 

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Pulsation-Dampeners

Compressors are an important item in many production processes. Undamped roots-type rotary piston blowers and screw compressors generate high noise levels that may exceed 160 dB (A).

Compressors are important items during many production processes. Undamped roots-type rotary piston blowers and screw compressors generate high noise levels that may exceed 160 dB (A). Hereby inducing damage into the piping and its adjuncts caused by low-frequency pulsations.

 

Why pulsations dampeners?

The pressure extremes generated by the compressor are evened out with a pulsation dampener. Advantages are less periodic plant inspections and increased useful lifetime of the plant. In addition, the pulsation dampeners reduce the levels of noise radiated from the piping.

 

Extended experience

Over several decades, Q.E.I. built an outstanding reputation for supplying high quality pulsation dampeners. We have a long tradition in custom-built equipment which is designed for the complete satisfaction of the plant user. Q.E.I. demonstrated reliable, qualitative and guaranteed solutions, regardless of the installation complexity. To ensure a competitive pricing, we fabricate our dampeners in economic locations.

 

Principles of operations

One or more choke tubes connect through two or more separate expansion chambers in a single housing. The main frequencies generated by the compressor are engineered to attenuate noise. Fluctuations in pressure are significantly diminished and can be reduced to a residual peak-to-peak pulsation level, if desired. The rotary speed of the compressor and the delivered gas flow determine the number and positioning of the choke-tubes, even when a variable speed compressor is installed.

 

Custom made dampeners

Demands upon the construction of the pulsation dampeners are high, due to the extremer loadings. When a standard design no longer meets the requirements, Q.E.I. designs a custom-built dampener, which is determined by following complex studies.

 

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In-line-Dampeners

The process industry employs many regulating and control valves. To control pressures noise the use of the valves is an unwanted by-product.

The process industry employs many regulating and control valves. To control pressures noise the use of the valves is an unwanted by-product. In the piping this can attain 150/ 160 dB(A) thus forming a serious nuisance. Dangerous hearing damage and general discontent when the valves operate during night times are the results. By interposing, an in-line dampener immediately connected to the valve providing constructive measures against the nuisance.

High quality in-line dampeners from Q.E.I.

Q.E.I. has been at the forefront of the design, fabrication and supply of high quality in-line noise dampeners for industry for many years. In addition to a standard range of dampeners, Q.E.I. has an engineering group specialised in producing solutions for each specific application. We are able to help you apply the optimum solution to your problem.

Principles of operations 

Our in-line dampener comprises an inlet diffuser zone, an expansion zone and an acoustic absorption zone, all arranged along a single axis. The diffuser zone conditions the flowing medium so that the noise spectrum and fluid pressure are optimised for the absorption zone. The expansion zone provides a randomisation of the noise characteristics to increase the efficiency of the absorption zone. Noise is attenuated by friction across the fibers and the energy is being dissipated as heat energy in the absorption zone. Diffuser design, arranged for staged pressure drop and precise noise control, permit the dampener to accept high inlet pressure. The noise radiated by the control valve is attenuated by reducing velocities within the valve body.

Custom-built units 

Individually designed and fabricated to meet the specific requirements of the plant. The expertise that we have amassed by has contributed to the leading position of Q.E.I. within the industry. Our motto is “To go beyond the point where others stop” and this has been demonstrated many times.

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Baffle-Silencers

Baffle silencers, housed in rectangular or cylindrical enclosures, which include one or more acoustic absorbent baffles.

Baffle silencers, housed in rectangular or cylindrical enclosures, which include one or more acoustic absorbent baffles. Constructed as a cassette, each baffle contains the absorbent material that converts noise energy into friction heat. Different types of absorbent materials are used dependent upon specifications and noise attenuation. The baffle thickness (spacing and length) has two different functions, the amount of noise attenuation and the frequencies treated.

Applications 

Our baffle silencers are used in a wide variety of applications heating- and air-conditioning ducting.

  • Separator cyclones
  • Compressor systems
  • Boiler vents
  • Fans
  • Electric motors
  • Compressor systems
  • Internal combustion engines

Custom design

Q.E.I. developed an advanced computer program that objectifies the results of laboratory and on-site measurement of baffle silencers. The program interpolates the differencing between performances and dimensions of the baffles.  The baffle silencers are not restricted to standardised proportions in production. The results are that the silencers can be fitted into the available space and noise spectrum, precisely adjusted to meet the required levels. Custom design ensures that oversized silencers are not fitted and to attain economical production.

Custom building permits construction in selected materials. The use varies upon the job specifications and may be furnished to meet high temperatures, corrosive media or hygienic requirements. Examples are:

  • Steel plate with electrolytically bonded zinc coating
  • High chrome-nickel alloy plates with sound absorbent selected for extreme conditions.

Where high velocities are inevitable, chrome-nickel alloy wire gausses will be fitted to minimise erosion.

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Vibration-Isolation

High quality steel and steel/polymer isolators provide the solutions to most of the vibration problems that we encounter.

High quality steel and steel/polymer isolators provide the solutions to most of the vibration problems that we encounter. We offer designed units for special cases, so that we can offer the optimum resolution of the vibration problem. Q.E.I. represents the Paulstra/ Vibrachoc range of isolators.

Rotary and vibrating machines

Which anti vibration mount is suitable for your application? A faulty selection may lead to insufficient isolation of the vibration and in the worst case a resonance that amplifies the vibration. Therefore, we require certain basis data in order to select the correct isolator for your application.

Which anti vibration mount is suitable for your application?

A faulty selection may lead to insufficient isolation of the vibration and in the worst case a resonance that amplifies the vibration. Therefore, we require certain basis data in order to select the correct isolator for your application.

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Separators

A unique series of separators are an important range of supply for Q.E.I.  Our separators, very efficient and reliable units, find application in many sectors of industry.

A unique series of separators are an important range of supply for Q.E.I.  Our separators, very efficient and reliable units, find application in many sectors of industry.

The purpose of separators 

Developed for the effective removal of solid particles from gas and vapour streams.  Advantages are a reduction in maintenance cost, reduction on down time on equipment and particle emission into the environment. Furthermore, it increases profit from product recovery.

Principles of operations

Elements induce a rotary flow into the process system. The resulting centrifugal forces carry the particle away from the gas stream. Collecting the liquid or solid particles and draining them away through a separate outlet. Fine control of velocities minimeses the pressure drop.

Some applications 

  • Protection of equipment, turbines, against damage caused by particles or droplets
  • Recirculation of condensate for steam applications
  • Recovery of chemical solid and precious materials.

Safe and reliable

  • Separators contain no moving parts
  • Once installed no further maintenance required
  • Built to last operating in exposed locations

Advice and service 

Our technical advisers will consult with you and carefully select the best model for your particular application. Q.E.l. assures you decades of up-to-date and practical experience.

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Exhaust-Silencers

Leading motor suppliers worldwide use Q.E.I. exhaust silencers. We have a range of standard silencers and a design team dedicated and specialized in producing custom-built unit for non-standard solutions.

Leading motor suppliers worldwide use Q.E.I. exhaust silencers. We have a range of standard silencers and a design team dedicated and specialized in producing custom-built unit for non-standard solutions. Examples here are cases with space limitations and very demanding attenuation requirements. We combine expertise with innovative solutions for difficult and complex problems. Our silencers are quality products and guaranteed to meet the specified noise levels. Fabricated in economical locations and supplied at the keenest prices.

Principles of operations 

Depending on your specifications, each silencer design may be based on noise absorption or upon combined resonance/ absorption. In both cases, a spark-arresting version is available.

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Pulsation analysis and control

Positive displacement pumps or compressors are frequently used in many different applications. They share however one common problem: due to their working principle socalled pulsations will be generated.

Positive displacement pumps or compressors are frequently used in many different applications. They share however one common problem: due to their working principle socalled pulsations will be generated. The geometry of the connected piping and equipment can further amplify these pulsations due to acoustical resonances. These resonances may deteriorate the performance of equipment or, even worse, coincide with mechanical natural frequencies of parts, eventually leading to failure. Although the principle of acoustical and mechanical resonances is simple, solutions undertaken may reveal unexpected increase of problems if one does not fully understand the interaction between pump or compressor and load cases, duties and operating cases.

Baffle silencers, housed in rectangular or cylindrical enclosures, which include one or more acoustic absorbent baffles. Constructed as a cassette, each baffle contains the absorbent material that converts noise energy into friction heat. Different types of absorbent materials are used dependent upon specifications and noise attenuation. The baffle thickness (spacing and length) has two different functions, the amount of noise attenuation and the frequencies treated.

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