ACOUSTIC DOOR

In a situation where there can be leaks around a door, through which sound can pass, there will be reduced sound attenuation. Therefore, not only does the fabrication period of FREETECH Acoustic Door is carried out in great care, but also the installation process is meticulously done to ensure high performance and quality. The importance of good sealing method can never be underestimated. A door with a reduction factor of 40dB with a leakage factor of only 1% will have a true reduction of 20dB.

APPLICATIONS

FREETECH Acoustic Doors are excellent for sound attenuation and fire resistant performance within certain environments that need a control of sound transmission through doorways. Typical applications are as the following:

• control rooms.
• hotels and hospitals. 
• office buildings. 
• plant rooms. 
• genset room

CONSTRUCTION

FREETECH Acoustic Doors come in two different types; steel and timber. They are designed to have a combination of superb acoustic performance with attractive finishes and easy installation. The doors consist of door leaves that contain an acoustic infill, selected to provide high damping and minimum acoustic coupling to ensure high transmission loss. The outer and inner skins are of two different thicknesses to control the resonance effect. The doors come in complete sets that include frames, latch, locking system, hinges and door closer where applicable. For steel doors, high gauge steel is used in constructing the door frame to rigidly support the door leaves. Due to the heavy weight of the door leaves, a special designed adjustable ball bearing hinges are use to ease the opening and closing of the door. For timber doors, high quality veneer finishes are used to ensure best performance and aesthetically satisfying.

The standard sizes of FREETECH Doors which can be delivered almost immediately are as follows:-

EXHAUST SILENCER FREETECH

Exhaust Silencers come in standard, stock silencers for general-purpose applications and custom models to fit most OEM engines. These include: - Model IXP - Multi-Chamber Reactive Type Attenuation - 30 dB Model IXS - Straight Through Absorptive Type Attenuation - 20 dB Model IXC - Supercritical or Combination Attenuation - 35 dB.

APPLICATIONS

FREETECH Exhaust Silencers are designed to efficiently reduce inlet and discharge noise of diesel engines, blowers, vacuum pumps, compressors and all situations requiring control of intake or outlet equipment noise.

CONSTRUCTION

All silencers are constructed from heavy gauge hot rolled cold quenched sheet steel with all welded construction. Internal components are stiffened and braced to minimise resonances and vibration induced fatigue. Flanges are supplied to Table C or American National Standard Institute (ANSI) requirement. Threaded pipe ends are to BSP or metric threads. Drain plugs are fitted as standard for removal of condensate. All external surfaces are finished with high quality silicone based heat resistant aluminium paint which provides lasting protection at temperatures up to 600 0C.

SELECTION GUIDELINES

When designing an exhaust system there are a number of factors that should be considered to maximize the design in terms of performance and cost. A few of the items that should be taken into consideration include:

-  Acoustic Environment into which exhaust is discharging 
- Engine Rating, i.e. - exhaust flow 
- Allowable engine back pressure 
- Engine exhaust outlet noise level 
- Engine Exhaust Outlet Design, i.e. single or dual outlets 
- Exhaust Piping Arrangement within engine room 
- Exhaust Piping Support, Anchoring, and Guiding 
- Exhaust Stack Height 
- Configuration of Exhaust Silencers, i.e. single or dual inlet

VENT SILENCER

Vent Silencers reduce the noise produced by the expansion of gas or steam from elevated pressures to atmospheric pressure. These absorptive silencers are used to suppress noise generated by high velocity gas streams such as steam vents, safety relief valve outlets, system blow downs and purge outlets. Each vent silencer is designed to attenuate the noise level to the required sound pressure level criteria at a given distance from the silencer. Model IVS - Acoustic Diffuser & Expansion

APPLICATION

Vent silencers effectively silence high-velocity air, steam, and gas vents and blowdowns to atmosphere where sonic or critical conditions exist in the valve or pipes. Typical applications include:

• steam boiler relief valves
• superheater header relief valves
• boiler startup and purge
• high-pressure air vents
• natural gas blowdowns
• switch valves
• compressor blowoffs
• autoclaves
• steam ejectors

CONSTRUCTION Typical vent silencers are welded heavy-duty units. The inlet nozzle and diffuser are constructed of steel and are welded. The diffuser provides controlled pressure expansion to atmosphere and uniform flow distribution through the acoustic section of the silencer. The lined inlet plenum (expansion chamber) of the silencer is designed with a double shell separated by a layer of acoustic insulation and sound-deadening material. The inner shell is solid to prevent shell radiated noise and migration of the acoustic fill. The transmission loss across the plenum and bottom head is comparable to the silencer attenuation.

SELECTION GUIDELINES

Use the following design information from the valve data sheet for system analysis and silencer selection:

1. Type of gas
2. Molecular weight or specific gravity
3. Ratio of specific heats
4. Flow rate (lb/hr, ACFM or SCFM)
5. Pressure and temperature upstream of valve and silencer
6. Maximum allowable pressure drop (PSI) for valve and silencer
7. Manufacturer’s name, and valve type and size 8. Unsilenced noise levels from valve (if available)
8. Silenced noise level (required at desired distance from source)
9. Silencer inlet size and pressure rating
10. Inlet orientation, axial or side
11. Silencer orientation, vertical or horizontal
12. Piping arrangement, including schematic if available
13. Other required options