2004年12月23日 · We have an office argument going about the use of ball valves versus gate valves on a sewer force main. This particular project is a 12" force main running about 2.5 miles and discharging into a manhole, but I would like your opinions on sewer force main valving in general. The project is...

2002年3月11日 · Obviously in a critical throttling service you would never use an el cheapo ball valve. I run into lots of plug valves on older installations all the time. You see them a lot in old gas plants, oilfields, and old LPG/NGL terminals. I think it's because 50 years ago there were no PTFE seals, so if a 1/4 turn valve was wanted, you used a plug valve.

2007年1月31日 · The cone inside the plug valve is less likely to require complete removal for maintenance. Ball valves disrupt the flow of the medium less than other types of valves, but the flow cannot be changed; plug valve flow, however can be changed by changing the size and shape of the plugs and seats.

2003年3月31日 · Which covers but not limited to Gate(single/double), Wedge , Globe, Disc (for Swing Check as well as Gate), Ball (V-ball, full ball, etc.) and Plug (Globe, Choke, Plug valve, Diaphragm valve). Plug is a more convenient term to pronounce since most of the time we refer it to a conical (male) shape of the sealing element, as for the seat inner ...

2008年12月9日 · A good constructed gate valve will have a very long service-free life, and in smaller sizes up to 10 inches be very much cheaper than a plug valve. Modern constructions of standard resilient gate-valves have overcome the earlier common defects of poor quality inner surface (thicker and better), corrosion of stem and stem nut (correct material ...

2006年10月17日 · "NONLUBRICATED" plug valves are actually better lubricated that the lubricated types. In a nonlubricated plug valve the plug rides in a (usually) PTFE sleeve. Set-torque of a nonlubricated plug valve peaks at around 72 hours, as the TFE sleeve cold-flows to match whatever microscopic imperfections exist in the surface of the plug.

2008年5月29日 · Globe valve: A valve where a disc (or for for instance for regulating globe valves a plug) is moved (screwed multiturn, usually) down to close the valve. A plug valve: a valve where a cylindrical or sligtly cone formed plug with a throughgoing cylindrical opening, is moved 90 degrees on the stem axis to open or close the valve (similar to a ...

2009年1月12日 · API 6D is the primary standard for valves used in pipeline service, including gate, plug, ball and check valves. Occasionally refinery and petrochemical purchasers will reference the more stringent testing requirements of 6D although the valve may have built under API 600, 602, 608 or 609 design criteria.

2013年5月13日 · In the 1970's quarter turn valves became widely available. The first of these position seated valves was the plug valve followed by the now-ubiquitous ball valve. Full shut occurs when the seat completely blocks the flow path and going further would open the flow path on the other side. David Simpson, PE MuleShoe Engineering

2005年12月12日 · The key difference is called "linearity". For a needle valve, the flow vs. valve opening is nearly linear (e.g., if the valve is 30% open then it will pass about 30% of it's maximum flow). The linearity of a gate valve is nearly non-existant. A gate valve will pass 100% of maximum flow at about 25% open. At 10% open it will pass about 5% of ...