Depending on the needs, consumers can choose different types of valves. As the valve is to control the pipeline medium, if the choice of poor quality valves, likely to cause leakage of water and other media, resulting in housing into the water, resulting in the loss of property. Therefore, the purchase of good quality valve is very important, the specific attention should be paid to the following points: 1) When purchased, the visual valve surface should be no blisters; plating surface should be uniform, should pay attention to whether peeling, cracking, scorching, Flaking, dark spots and obvious pitting and other defects; Spray the surface tissue should be fine, smooth and uniform, not sagging, exposed defects. The above defects will directly affect the service life of the valve. 2) The pipe thread of the valve is connected with the pipe. Visual inspection of the surface of the screw thread shows obvious defects such as dents and broken teeth when it is purchased. Pay particular attention to the fact that the effective length of screwing of the pipe thread and the connecting piece will affect the reliability of the sealing Sex, purchase, pay attention to the effective length of the pipe thread. General DN15 cylindrical thread effective length of about 10mm. 3) Gate valve, ball valve is generally marked on the valve body or handle nominal pressure, optional according to their needs. 4) If consumers want to replace the existing gate valve or ball valve, it is necessary to clarify the length of its structure, so as not to buy after installation. 5) Triangle valve pipe thread with internal and external thread two, consumers should choose according to need; also note that there are some zinc alloy valve on the market today, the valve price is lower than the average, But easy to cause corrosion and fracture, the use of a long time, will rot in the pipeline, resulting in maintenance difficult situation. Consumers must carefully choose when purchasing the valve.