Please forward this error screen to 64. Bellows provides custom designed expansion joints in duct work and fabricated duct work assemblies. The assemblies may include fabricated elbows, pre insulated duct pdf, and straight sections of duct work, in carbon steel or stainless steel, and in diameters of 42″ or larger. The duct sections can include fabric or metallic expansion joints and can be rectangular or round.
Fabric Pipe Expansion Joints Fabric pipe expansion joints are often used in ducts which carry hot gases at low pressures. The major design parameters are the temperatures and flow rates of the gases and the amount and abrasiveness of solids suspended in the gases. Layers of different fabrics insulation can be combined to accommodate the temperatures and pressure in the system. The fabric belt may need to be replaced periodically. What fabric is used in manufacturing expansion joints? How many layers are in a non-metallic expansion joint?
What is the maximum pressure for a fabric expansion joint? Do you manufacture fabric joints in any other material beside PTFE? The needed airflows include, for example, supply air, return air, and exhaust air. Ducts commonly also deliver ventilation air as part of the supply air. A duct system is also called ductwork. Galvanized mild steel is the standard and most common material used in fabricating ductwork because the zinc coating of this metal prevents rusting and avoids cost of painting.
Rectangular ductwork commonly is fabricated to suit by specialized metal shops. Round duct is made using a continuous spiral forming machine which can make round duct in nearly any diameter when using the right forming die and to any length to suite, but the most common stock sizes range evenly from 4″ to 24″ with 6″-12″ being most commonly used. Stock pipe is usually sold in 10′ joints. Aluminium ductwork is lightweight and quick to install. Also, custom or special shapes of ducts can be easily fabricated in the shop or on site. The ductwork construction starts with the tracing of the duct outline onto the aluminium preinsulated panel.
Aluminium tape is applied to all seams where the external surface of the aluminium foil has been cut. A variety of flanges are available to suit various installation requirements. All internal joints are sealed with sealant. Aluminum is also used to make round spiral duct, but it is much less common than galvanized steel. Traditionally, air ductwork is made of sheet metal which was installed first and then lagged with insulation. Today, a sheet metal fabrication shop would commonly fabricate the galvanized steel duct and insulate with duct wrap prior to installation.
However, ductwork manufactured from rigid insulation panels does not need any further insulation and can be installed in a single step. A rigid phenolic insulation ductwork system is listed as a class 1 air duct to UL 181 Standard for Safety. Fiberglass duct board panels provide built-in thermal insulation and the interior surface absorbs sound, helping to provide quiet operation of the HVAC system. The duct board is formed by sliding a specially-designed knife along the board using a straightedge as a guide. They have a variety of configurations. In the United States, the insulation is usually glass wool, but other markets such as Australia, use both polyester fibre and glass wool for thermal insulation. Flexible duct is very convenient for attaching supply air outlets to the rigid ductwork.