1) purchase, eyeballing the valve surfaces should be free from trachoma; plating surface gloss should be uniform, it should be noted that there is no peeling, cracking, burning, threadbare, spalling, black spots and obvious defects such as pitting; spraying surface tissues should be fine, smooth, no sagging, threadbare and other defects. These flaws will directly affect the service life of the valve
2) pipe threads of the valve is connected to the pipe, purchasing Visual thread when the surface has no dents, broken teeth and other apparent defects, in particular, to note that pipe thread with connectors-rotating the effective length will affect the reliability of sealing, buy should pay attention to the effective length of pipe thread. Effective length of cylindrical pipe thread DN15 10MM.
3) gate valve, ball valve in the valve body or marked with nominal pressure on the handle, when you purchase according to their needs.
4) if consumers want to replace the existing gate or ball valve, to understand its structure length, cannot be installed after purchase.
5) triangle valve pipe thread with internal thread and external thread in two, according to the needs of consumers to purchase; also note that is currently on the market are zinc alloy angle valve, the valve lower prices than the average, but easy to fracture caused by corrosion, use long after rot in the pipes, caused maintenance difficulties.