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发表于 2008-8-6 02:58:38
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来自:北京
Plumbing, Pipe Fitting, and Sewerage aim express
Plumbing, Pipe Fitting, and Sewerage aim express
世纪互联
pipe fitting is the occupation of installing or repairing piping or tubing systems that convey liquid, gas, and occasionally solid materials. This work involves selecting and preparing pipe or tubing pipe fitting, joining it together by various means, and the location and repair of leaks.
pipe fitting work is done in many different trades: Plumbing, HVAC, manufacturing, fire prevention, and many others. Pipe fitters (sometimes called simply "fitters") are represented in the USA by the United Association of Journeymen and Apprentices of the Plumbing and pipe fitting Industry of the www.pipe.org United States and Canada.
Fitters work with a variety of pipe and tubing materials including several types of plastic, copper, steel, iron, aluminium, clay, and lead.Steel pipe (or black iron pipe) was once the most swing stock popular choice for supply of water and flammable gases, but fell from favor as water pipe in the mid 20th century due to its tendency to rust. Steel pipe is still used in many homes pipe fitting dimensions and businesses to convey natural gas or propane, and is a popular choice in fire sprinkler systems due to its high heat resistance.
In Canada, in respect to natural gas (NG) and propane (LP gas), black iron pipe (BIP) is used to connect an appliance to the supply, it must however be marked (either painted yellow or yellow banding attached at certain intervals) and certain restrictions apply to which nominal pipe size (NPS) can be put through walls and buildings. With propane in particular BIP can be run from an exterior tank (or cylinder) provided it is well protected from the elements and an www.swagelok.com anode-type of protection is in place for when the pipe is to be installed underground.
Copper tubing is most often used for supply of hot and cold water, and as refrigerant line in HVAC systems. There are two basic types of copper tubing, soft copper and rigid copper. Copper pipe fitting tubing is joined using flare connection, compression connection, or sweat (solder). Copper offers a high level of resistance to corrosion, but is becoming very costly.
Compression fittings use a soft metal ring (the compression ring) which is squeezed onto the pipe and into the fitting by a compression nut. The soft metal conforms to the surface of the tubing and the fitting, and creates a seal. Compression connections do not typically have the long life that sweat connections offer, but are advantageous in many cases because they are easy to make using basic tools. A disadvantage in compression connections is that they take longer threaded pipe fitting dimensions to make than sweat, and sometimes require retightening over time to stop leaks.
PVC and CPVC
PVC or polyvinyl chloride, is the most popular choice in plastic pipe. It is rigid, and uses thread or solvent weld (glue) connections, it also can be heat fused. It is available in various pressure ratings, with the most common choice being Schedule 40 for pressurized uses, it is available for waste water lines. Standard PVC can only be used for cold pipe fitting water supply, and is a very popular choice for drain line. |
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