Mastering the key points for avoiding pitfalls in industrial valve selection and avoiding these common mistakes is crucial for more accurate and practical selection. The following five selection pitfalls are easily fallen into by 90% of valve selectors and should be carefully avoided.

Myth 1:

Focusing solely on pipe diameter while ignoring the matching of medium and pressure is a fundamental selection issue. Some people use only the DN pipe diameter as the sole criterion, directly selecting any valve of the same diameter, completely ignoring the core requirements of medium characteristics and working pressure.

For example, in a high-pressure natural gas pipeline, selecting a cast iron valve of the same diameter that is only suitable for low-pressure clean water will quickly lead to sealing leaks and even safety hazards due to insufficient valve body pressure resistance.

To correct this problem, the type of medium and working pressure should be considered before the pipe diameter. First, determine the valve material and nominal pressure rating based on the medium and pressure, and then match the corresponding pipe diameter.

Myth 2:

Blindly choosing gate valves for large-diameter applications, ignoring installation costs and space limitations. While gate valves offer the advantage of low pressure loss under high-flow conditions, their large size and high vertical installation space requirements, coupled with higher procurement and installation costs compared to butterfly valves of the same diameter, make them less desirable.

For example, in municipal water supply pipelines with a diameter of DN300 or larger, blindly choosing rising stem gate valves not only necessitates higher pipeline supports, increasing installation and material costs, but also creates inconvenience for later inspection and maintenance due to the limited space required for valve stem movement.

To correct this problem, for large-diameter, low-pressure, and normal-pressure water supply, drainage, and sewage treatment applications, wafer-type butterfly valves should be prioritized. Their compact structure significantly saves installation space, has lower procurement and installation costs, and fully meets the demands of high-flow applications.

Myth 3:

Pursuing high sealing performance and blindly choosing ball valves. While ball valves do offer excellent sealing performance and are suitable for gases and liquids with high sealing requirements, this doesn't mean they're suitable for all scenarios. Some people use sealing performance as the sole criterion, selecting ball valves for all pipelines, resulting in wasted costs and even affecting performance.

For example, using ball valves in large-diameter, low-pressure sewage pipelines not only incurs significantly higher procurement costs than butterfly valves, but impurities in the sewage can also easily clog the ball, causing poor opening and closing and ultimately reducing the user experience.

To correct this problem, it's not about blindly pursuing high sealing performance, but rather matching sealing performance to the operating conditions. Ball valves are preferable for small-diameter liquid pipelines requiring precise gas control, while eccentric butterfly valves are sufficient for large-diameter, low-pressure liquid pipelines containing small amounts of impurities.

Myth 4:

Ignoring operating frequency and blindly selecting gate valves for high-frequency switching conditions. Gate valves are designed for long-term fully open operation with occasional switching. However, the frequent lifting and lowering of the gate and stem causes wear on the sealing surfaces and transmission components, leading to seal failure and switching difficulties.

For example, in the media transport pipelines of automated production lines, multiple switching operations per minute are required. If gate valves are used, leaks will appear within months, and frequent maintenance and replacements will significantly increase production costs.

To correct this problem, ball valves or butterfly valves should be prioritized for these high-frequency switching conditions. Both operate at a 90-degree angle, have fewer transmission components, and experience far less wear than gate valves, making them better suited for high-frequency operation.

Myth 5:

Incompatible valve material selection leads to corrosion and leakage of the valve body and fittings. The valve material directly determines its compatibility with the medium. Selecting the material according to the corrosiveness, temperature, and pressure characteristics of the medium prevents malfunctions due to insufficient material and avoids cost waste caused by excessive material selection.

For example, using ordinary cast iron valves for corrosive media to save costs will result in valve body corrosion and aging of seals; using stainless steel valves for conventional clean water conditions is wasteful of material.