Internal leakage of the valve

Inevitably, valves are generally considered to be leaky

The sealing performance of a valve refers to the ability of its various sealing parts to prevent the leakage of the medium, and it is the most important technical performance indicator for valves. There are three sealing areas in a valve: the contact point between the moving part and the two sealing surfaces of the valve seat ； The interface between the packing and the valve stem as well as the packing box ； The connection between the valve body and the valve cover. The leakage in the former case is known as internal leakage, which is what is commonly referred to as poor sealing; it affects the valve’s ability to block the flow of the medium. For cut-off valves, internal leakage is not allowed. The leaks in the latter two locations are called external leaks, that is, the medium leaks from inside the valve to outside it. Leaks can lead to material loss, environmental pollution, and in severe cases, accidents. For flammable, explosive, toxic, or radioactive media, leaks are absolutely unacceptable; therefore, valves must have reliable sealing properties. For products based on common valve technology, whether they are shut-off valves or control valves, their sealing surfaces are not subject to any erosion; wear is minimal, and they are resistant to wear. Their excellent sealing performance ensures zero leakage both internally and externally, thereby saving energy, protecting the environment, and improving work efficiency. A check valve is also known as a non-return valve, one-way valve, backflow valve, and backpressure valve. Check valves are used in piping systems; they open and close automatically due to the force generated by the flow of the medium itself within the pipeline. They belong to the category of automatic valves, and their main functions are to prevent backflow of the medium, stop the pump and driving motor from rotating in reverse, and prevent the leakage of the medium from containers. Check valves can also be used in pipelines that supply auxiliary systems whose pressure may rise above the system pressure. Check valves can be mainly divided into swing check valves (rotating around their center of gravity) and lift check valves (moving along their axis). Check valves are more prone to internal leakage than ball valves, mainly because the medium or impurities in the medium cause damage to the sealing surfaces; soft seals are more likely to experience internal leakage than hard seals.

Ball valves have a sealing function; if internal leakage occurs, the gasket can be replaced to restore sealing performance. The check valve has poor sealing performance; it is generally used to prevent fluid from flowing back rapidly and causing damage to equipment or pumps. Internal leakage is a characteristic inherent in the design of such valves, and it cannot be changed. To prevent internal leakage, a stop valve can be added.

Ball valves have a sealing function; if internal leakage occurs, the gasket can be replaced to restore sealing performance. The check valve has poor sealing performance; it is generally used to prevent fluid from flowing back rapidly and causing damage to equipment or pumps. Internal leakage is a characteristic inherent in the design of such valves, and it cannot be changed. To prevent internal leakage, a stop valve can be added.

There are many reasons for internal leakage in valves, mainly including internal factors (incorrect selection, poor quality, unreasonable design, substandard sealing materials, etc.) and external factors (severe operating conditions, improper opening and closing, scratches during installation, rough or incorrect handling, etc.). If it’s not a genuine seal damage. Internal leakage can be resolved simply by tightening and adjusting the valve. If it is a genuine seal damage, the best solution is of course to stop the machine, replace the seal or the valve. If it cannot be stopped/ceased, repair must be carried out online while under pressure; there is a certain success rate for such repairs, and even professional teams cannot guarantee a 100% successful repair. In companies with advanced technology, once online repair is successful, the valve can be opened and closed freely, and its functional performance returns to its original state. If you want relevant information, please send me a message within the platform so we can all improve together.