Hammer union

Hammer union is a kind of quick connection that can connect pipe or fittings by copper hammer. The most popular brand is FMC weco wing union which divided into many figures. But for our well testing job or high pressure well service, we normally use FIG206, FIG602, FIG1002, FIG 1502, FIG2202. The front 1 or 2 number normally means pressure, last one means type. For example, FIG 1502, the working pressure is 15,000psi, and connection type is 02. The highest class is FIG 2202, which is work under 15,000psi in sour service.

From the four pictures, we can find that the first three is pipeline thread connection, the forth one is butt-weld connection. As yield strength of pipeline thread can’t match FIG 2202’s request.
Since FIG2202 is butt-welding connection, is it possible for other FIG union being butt welding? The answer is YES. Let us share one of our G.A drawings which are 4” FIG 206 sch160. PS: sch160 is pipe wall thickness mark from ASME standard.

So for all figures, butt welded is applicable.
Maybe someone will ask what thread type is between wing nut and female. Frankly speaking, this information is cost of money. We only can say it is ACME thread. But there is big issue for this ACME thread connection. As there is normal ACME and mod ACME, so for several figure type, different acme is adopted in different location. In my former post, we mentioned that we have compensate new check valve to end user as below photo which make us much loss as the difference use of ACME thread.
Sometimes, information is more valuable.