A pig valve is a trunnion ball valve with a port milled into the side of the valve through which you can insert a pig and seal the port with a pig closure. These come in both launcher and receiver models.
A Pig Launcher is a system of valves, piping, fittings, and cavities to allow you to launch a variety of pigs.
A pig valve is a manufactured component, and pig launcher is a fabricated system of components. In 6-inch they cost about the same. Smaller than 6-inch the pigging valve tends to be significantly less expensive. Bigger than 6-inch, the pig launcher is less expensive.
davidysong,
No, pigging valves are installed in lieu of launchers and receivers, how could it be otherwise? A pig launcher launches a pig. A Pigging Valve launches a pig. A pig receiver receives a pig. A Pigging Valve (receiver) receives a pig up against a perforated plate on the downstream side of the pigging valve. Installing pigging valves on a conventional launcher or receiver would be a serious waste of money for the launcher and it would render a conventional receiver unusable.
Ione,
Was there any mention of pigging valves in those links? I couldn't find any.
I thought the OP was approaching pigging procedures for the first time and might need abrief introduction to related terminology (overthinking sometimes leads to wrong conclusions)
davidysong,
You can find a video of what zds04 has explained at the link below
