Thread Content
A check valve is a valve whose opening and closing elements open or close on their own due to the force of the flowing medium, in order to prevent the medium from flowing in reverse. Check valves belong to the category of automatic valves; they are primarily used in pipelines where fluid flows in one direction only, allowing the fluid to move in that direction alone in order to prevent accidents. What are the different types of classification for check valves? Check valve: Nominal pressure or pressure class: PN1.0–16.0 MPa, ANSI CLASS 150–900, JIS10–20K. Nominal diameter: DN15–900, NPS 1/4–36. Connection methods: flange, butt welding, threading, socket welding, etc. Operating temperature range: -196°C–540°C. Valve body materials: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. By using different materials, check valves can be suitable for various media such as water, steam, oils, nitric acid, acetic acid, oxidizing agents, and urea. General-purpose lift-type check valves should be installed on horizontal pipelines, while vertical lift-type check valves and foot valves are generally installed on vertical pipelines with the fluid flowing from bottom to top. The installation location of a swing check valve is not restricted; it is usually installed in horizontal pipelines, but it can also be installed in vertical or inclined pipelines. When installing a check valve, special attention should be paid to the direction of fluid flow; the normal flow direction of the fluid must match the direction indicated by the arrow on the valve body, otherwise it will prevent the fluid from flowing properly. The bottom valve should be installed at the bottom end of the water pump’s suction pipeline. Check valve: When closed, it can generate water hammer pressure in the pipeline, which may cause damage to the valve, pipelines, or equipment in severe cases. This is especially true for large-diameter or high-pressure pipelines, so those selecting check valves should pay close attention to this issue. A check valve, also known as a one-way valve or non-return valve, serves to prevent the medium in the pipeline from flowing in reverse. The bottom valve on the water pump’s suction pipe also belongs to the category of check valves. Classified by structure, check valves can be divided into lift-type check valves, swing-type check valves, and butterfly check valves. Lifting check valves can be divided into vertical and horizontal types. Swing check valves are divided into three types: single-disc, double-disc, and multi-disc. Butterfly check valves are of the straight-through type; the aforementioned check valves can be connected in three ways: threaded connection, flange connection, and welding. They can be divided into three types: lift-type check valves, swing-type check valves, and butterfly check valves. Lifting check valves can be divided into vertical check valves and horizontal check valves. Swing check valves are divided into three types: single-disc check valves, double-disc check valves, and multi-disc check valves. Butterfly check valves are straight-through check valves. The aforementioned types of check valves can be classified, in terms of connection method, into threaded check valves, flanged check valves, and welded check valves.