• Categories:News
• Author:
• Origin:
• Time of issue:2019-09-11 22:40
• Views:

(Summary description)In the early 1980s, Ningbo, Zhejiang Province took the lead in developing manufacturing technology, which changed the history of long-term use of cast iron valves in China. In the manufacturing process, the sand casting forming process was initially adopted, and the forging process was changed in the early 1990s. At the beginning of the 21st century, China has become the world's copper valve manufacturing center. No matter from the process, product design, or mold production, valve casting, forging. (1) sand casting: the earliest production mode in the valve field, because the valve produced by this process is easy to produce sand holes and lead to a series of problems caused by product leakage due to insufficient pressure of the casting type. (2) hot forging: the valve body formed by forging will not have sand holes and its appearance will be more exquisite. Sand blasting, metalworking, parts assembly, product pressure test, packaging and sealing Selection principle According to the control function selection, all kinds of valves have their own functions, which should be paid attention to. According to the selection of working conditions, the technical parameters of common valves include nominal pressure, maximum allowable working pressure, working temperature (minimum and maximum temperature) and medium (corrosiveness and flammability). During selection, the above parameters of working conditions shall be consistent with the technical parameters of valves. According to the installation structure. The installation structure of the pipeline system includes pipe thread, flange, ferrule, welding, hose, etc. Therefore, the installation structure of the valve must be consistent with the installation structure of the pipeline, and the specification and size must be consistent. brass valve Installation mode The valve connected by pipe thread is connected with the pipe thread at the pipe end, wherein the internal thread can be cylindrical pipe thread or conical pipe thread, while the external thread must be conical pipe thread. The gate valve connected with the internal thread is connected with the pipe end, and the length and size of the external thread of the pipe end need to be controlled. In order to avoid excessive screw in of pipe end, the inner end face of the pipe thread of the top pressure gate valve will cause the valve seat deformation and affect the tightness. When the valve connected with pipe thread is installed and tightened, the hexagonal or octagonal part at the same end of the thread and the hexagonal or octagonal part at the other end of the valve shall not be spanned to avoid deformation of the valve. The flange of the flange connected valve and the flange of the pipe end shall not only be consistent with the specification and size, but also with the nominal pressure. In case of leakage of the valve stem during the installation and commissioning of the stop valve and gate valve, tighten the compression nut at the packing, and pay attention that the force shall not be too large to the extent of no leakage. Since the beginning of the 21st century, some well-known domestic copper valve manufacturers have broken the conventional thinking and have the courage to innovate and practice, and have developed a large number of new products, which has greatly improved the scope of application of brass valves in the field of engineering applications. In particular, the successful experimental development of all copper hydraulic control series not only makes a qualitative leap in the manufacturing process of copper valve products, but also greatly promotes the overall competitiveness of the copper valve industry.