1. When the ball valve is fully opened or fully closed, the sealing surface of the valve seat is not in contact with the medium;
2. The butterfly valve adjusts the flow distribution approximately linearly within the opening range of 0-60%;
3. Needle valve is a globe valve;
4. Cock is a plug valve, which is the transliteration of the word “switch” in the former Soviet Union. The use occasion is similar to that of the ball valve, but the sealing performance is worse than that of the ball valve.
Ball valves are divided into many structures. For the O-type ball valve with double seat, it needs to be purged for coking medium. If the medium particle content is large, the closed valve cavity is easily blocked and the valve cannot be opened. Sometimes it is designed as a single valve seat. High viscosity is not a problem.
The butterfly valve has a throttling effect when the opening degree is small, and the opening degree exceeds 30 degrees, which is similar to the quick opening characteristic, and the flow rate has little effect, which is related to the valve diameter and the structure of the butterfly valve. The larger the valve diameter, the more obvious the adjustment characteristic between 15-45 degrees. Specially designed discs can be approximately linear.
More than 90% of needle valves are globe valve structures. In a narrow sense, needle valves refer to globe valves with throttling needle-shaped discs. Needle valves in a broad sense refer to small-diameter instrument valves, sometimes in the form of plug valves and ball valves.
Quark refers to plug valve, plug valve is divided into hard seal, ferrule and oil lubrication, and now there is also general valve sometimes regarded as orbital plug valve. One advantage of the plug valve is that there is no closed valve cavity angular stroke valve, and it works well in some occasions. Hard seals are mostly used in crystallization media such as soda ash, and the sealing performance of this valve is not good. The sealing performance of the ferrule is better, and it is used in many industries such as asphalt, acetic acid and urea. The ferrules are mostly used in petrochemicals, and the most are the oil pipelines of oil depots.
The valve core of the regulating valve falls off more, and the valve stem falls off less. Generally, the valve core falls off because the valve stem is broken due to vibration, and it is disconnected at the connection position between the valve disc and the valve core. At this time, if the pressure difference is large, it is still possible for temporary use The effect is effective, but it refers to the cage-type regulating valve. The single-seat one will not work, and the valve disc will run. The valve stem falling off generally occurs at the connection position between the valve rod and the actuator, and the valve falling off will fail.
There are two types of three-way valves, one is a confluence valve, the other is a diverter valve, and the ports blocked by the disc falling off are different. It is generally related to the installation location and cannot be generalized.
Yuhuan Liqun Valve Co., Ltd. is a professional manufacturer of: 1. Brass angle valve, brass globe valve, check valve, ball valve-based valve series. 2. Plumbing series mainly include sanitary ware, European faucet (with pressure regulator valve) and brass pipe connection. 3. A series of garden tools based on various types of sprinklers and quick connectors.