Tryckfördelningar på ventilspjäll vid olika öppningsgrader och dess påverkan på ventilspindeln

Valves are used in the most pipe systems today. There are a lot of different valves used depending on the system. They all do have in common to withstand all possible kind of failure that might occur. Common issues are cavitation, water hammer and friction torque. Friction torque is dependent on the deflection of the valve due to the high load on the valve body, for a butterfly valve this will be the disk. The pressure distributed on the disk differ depending on the opening angle of the butterfly valve. Opening angles of 3, 15 and 30 degrees are investigated. The further the valve is opened the lower the pressure will be on the downstream side and also the total pressure on the disk is decreased. This investigation shows that the impact in terms of deflection angle is constant for the lower opening degrees but for 30 degrees of opening there is a drop in deflection angle on the shaft. This means that the shaft will absorb less force due to loading on the disk and lead to reduced friction torque. With use of the same inlet pressure the angle causing the deflection increased linearly