Internal leakage in the steam stop valve
Thread Content
Dear friends, what kind of valves do you use on the steam pipelines in your companies? Are there any brand recommendations? Our company uses J41H-16C stop valves (for steam pressures of 0.8 MPa) and J41H-16P valves for steam; the internal leakage with these valves is extremely severe – sometimes, even after replacing them with new ones, internal leakage occurs as soon as they are used once. Do everyone else have the same confusion? Or is there a problem with my selection? Does anyone have any good suggestions?
“Double-sided metal hard-sealed butterfly valves for district heating” GBT37828-2019 Scope: This standard applies to butterfly valves used in district heating systems with a nominal pressure of PN25 or less, a nominal size of DN1600 or less, a hot water temperature of 200°C or less, and a steam temperature of 350°C or less. \"Technical Code for Direct-Buried Steam Pipes in Heating Systems in Cities and Towns\" CJJ/T104-2014 4.1.1 Valves to be used in directly buried steam pipes should preferably be globe valves or gate valves without packing; when butterfly valves are used, eccentric hard-seal butterfly valves should be chosen. The nominal pressure of the valves should be one grade higher than the design pressure of the pipes, and proper insulation, waterproofing, and anti-corrosion measures must be taken.
Valve manufacturers can refer to the domestic manufacturers listed among the contributors to the standard «Double-direction metal hard-sealed butterfly valves for urban heating» GBT37828-2019
There are mainly several situations that cause internal leakage in steam pipes: 1. The pipe is not clean and contains solid particles, which erode the sealing surface. 2. The valve diameter is too small, resulting in high flow speeds that erode the sealing surface. 3. Frequent opening and closing of the globe valve leads to damage to the sealing surface (ceramic materials should be used for the seals in steam systems). 4. The valve’s installation location makes it prone to liquid slugging. 5. An improper pH level of the steam causes corrosion of the valve’s sealing surface. 6. The quality of the valve is poor. 7. Improper operation, such as failing to close the valve completely when it should be shut, results in erosion of the sealing surface. 8. Poor selection
Gate valves are generally preferred for steam, although globe valves can also be used. When making a selection, it is necessary to ensure that the medium used and the operating temperature of the valve meet the process requirements; based on the valve model, the material of the valve seat is incorrect
Product quality, pressure rating, and hydrophobicity all need to be considered
Shanghai Saibin Valves, please contact me