CDG Gate Valve: Advantages, Disadvantages, Installation, and Maintenance

CDG gate valves are used to shut off or connect media in pipelines. By selecting different materials, they can be used for various media such as water, steam, oil, nitric acid, acetic acid, oxidizing media, and urea. They are frequently used in oil pipelines. Most CDG gate valves are designed with a Dalian-style reduced diameter, and compared to cast steel gate valves of the same diameter, their advantages and disadvantages are slightly smaller, but their pressure and temperature ranges are higher than those of cast steel valves, and their sealing performance is also much better than that of cast steel gate valves, resulting in a longer lifespan. The flow direction of the medium is not restricted, just like other gate valves.

CDG gate valves have the following advantages:

1. Low fluid resistance, and the sealing surface is less susceptible to scouring and erosion by the medium.
2. Relatively easy to open and close.
3. The flow direction of the medium is unrestricted, causing no turbulence or pressure drop.
4. Simple shape, short structural length, good manufacturability, and wide range of applications.

The disadvantages of CDG gate valves are as follows:

1. Erosion and abrasion are prone to occur between the sealing surfaces, making maintenance difficult.
2. Larger external dimensions, requiring a certain amount of space for opening, and longer opening and closing times.
3. Relatively complex structure.

The following points should be noted regarding the installation and maintenance of CDG gate valves:

1. The handwheel, handle, and transmission mechanism are not allowed to be used for lifting, and collisions must be strictly avoided.
2. Double gate valves should be installed vertically (i.e., the valve stem is in a vertical position, and the handwheel is at the top).
3. For gate valves with bypass valves, the bypass valve should be opened first before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
4. Gate valves with transmission mechanisms should be installed according to the instructions in the product manual.
5. If the valve is frequently opened and closed, it should be lubricated at least once a month.