Noise Control Division
  100 Airport Executive Park
  Nanuet, NY 10954

  Tel 845-352-8877
  Fax 845-352-4464


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In-Line Diffusers

Model Designation LDF or LDF-P

Reactive device for the reduction of excessive noise from pressure reduction systems for steam, gas or air.

QUIETFLO model LDF in-line diffusers are designed to reduce the noise typically associated with pressure reducing valve applications. These diffusers are effective when treated as a system in combination with the valve to achieve the total pressure reduction required.

Diffusers can serve several functions:

They provide a method of dispersing the high pressure reductions typically seen at pressure reducing valves and regulators

They dissipate high energy noise and reshape the frequency spectrum, shifting the peak frequency to a higher octave band.

Where applicable, they can be designed to provide a desired back pressure on the valve.

Quietflo Diffusers are available in a range of materials, the most common being mild carbon steel. SS 304 is also available. Call for special material requirements-price and availability

In addition to our standard Diffuser Line, we offer drilled Diffuser Plates(model LDF-P) These plates are provided on request , in materials specified by our customers. The most common being A-516 and SS 304. Drilled diffuser Plates have 4 mounting tabs to facilitate mounting between customer pipe flanges of any size or rating.

In-Line Silencers

Model Designation LAS

For the reduction of excessive noise from pressure reduction systems for Steam, Gases, Natural Gas or Air. Special designs available for oxygen service, which also requires special cleaning procedures and lower velocities.

The noise generated by pressure reduction valves is predominantly high frequency.

QUIETFLO model LAS silencers are therefore of an absorptive design, to provide maximum attenuation of noise in the 1, 2 and 4kHz Octave Bands.

These silencers are ASME Code designed and hydrotested. ASME Code stamp is available upon request. Fabrication is sub-contracted to pre-qualified fabricators.

Gas enters the silencer through an inlet diffuser, designed to dissipate high energy noise and to reshape the frequency spectrum to insure maximum effectiveness of the multi-tubed acoustical section.

The primary expansion chamber allows continuous expansion of the gas stream, reducing velocity and turbulence, thereby decreasing the generated noise energy. The flowtube assembly is designed to an optimum length/diameter ratio to maximize noise absorption while minimizing pressure drop. The silencer shell is lined to minimize the effect of noise radiation as well as to provide additional noise attenuation within the silencer.


Stack Insert Silencers

Model Designation SIS or VSDS

This type silencer can be of the splitter type (Model SIS) or our specially designed multitube arrangement (Model VSDS), which has a higher attenuation per foot of length than the traditional splitter silencer.

Special mounting features allow the Model VSDS silencer to be dropped into the stack, positioned at the exit end of the stack. This reduces installation cost and time as the silencer hangs from the top edge of the stack. Maintenance costs are also reduced as the silencer can be easily removed for cleaning or inspection, as required.

Pressure drop can be tailored to customer needs more easily with the high performance multitube silencer Model DSVS.

Common materials used for these silencers are: SS 409, SS 304, and galvanized steel (flow temperatures below 400 F) Fabrication is sub-contracted to pre-qualified fabricators.


Vent & Blowdown Silencers

Model Designation VS or VSH

Vent and blowdown silencers are designed to eliminate excessive noise created by the discharge of high pressure gases and steam into the atmosphere. Vent silencers find wide applications in process vents, boiler and reactor blowdown, compressor start-up, and cryogenics switch valves. Vent silencers can be furnished with open end discharge or in-line, and vertical (VS) or horizontal (VSH) installation. QUIETFLO offers standard and custom designs to meet specific noise criteria and back pressure requirements.

These silencers incorporate an inlet diffuser which can be sized to provide any backpressure that the customer may require for his safety or relief valve.

Multiple inlets can be added to any Vent Silencer, making the Quietflo VS Silencer a potential cost saver since one silencer can accommodate the input from multiple sources.

Each inlet contains a diffuser section which allows the particular inlet to provide any backpressure requirement that the customer might need.

The silencers are designed to ASME Code but are not commonly pressure tested. Fabrication is sub-contracted to pre-qualified fabricators.



Gas Turbine Exhaust Silencers

Silencers-Model DSS

QUIETFLO custom engineers gas turbine exhaust silencers to meet stringent specifications involving high flow, high temperature and low pressure drop requirements. These exhaust silencers are used on either direct discharge from the turbine exhaust or in a bypass mode for cogeneration applications. In addition, QUIETFLO offers complete packaged gas turbine noise control systems.

Common materials used for this type silencer are: SS 409 & SS 304. High temperature designs incorporate “floating” perforated face sheets to accommodate thermal expansion thereby minimizing face sheet buckling/distortion.

Heavy frames ensure splitter rigidity and retention of acoustic fill. Formed entrance noses provide additional splitter strength and shape retention.

Silencer supports are custom designed and provided as part of our silencer assemblies.

Acoustic packing is selected according to temperature and velocity, with fiberglass cloth wrapping (erosion protection) as a minimum with SS 304 mesh screen added for severe flow conditions.

Fabrication is sub-contracted to pre-qualified fabricators.


Splitter Type Inlet & Exhaust Silencers

Model Designation ISS or DSS

QUIETFLO furnishes a complete line of inlet and exhaust silencers for centrifugal fans, blowers and engines. Silencers for rotary and axial fans are available especially designed to reduce the low frequency noise generated at the blade passing frequency.

These silencers can be provided with or without outer shells, as the splitters can be designed to fit within customer ducts.

Materials can be galvanized steel, SS 304 or any other commercially available material desired.

Fabrication is sub-contracted to pre-qualified fabricators.

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