What is a check valve? A check valve, or a one-way valve, is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. It is a type of two-port valves. In other words, it has two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. The check valve is available in a wide range of sizes and costs, check valves generally are very small, simple, or inexpensive. Check valve work automatically and most are not controlled by a person or any external…