1. The smoke leakage of the valve shows an upward trend. For the kitchen smoke exhaust valve, this may occur because when the temperature inside the furnace rises to a certain value, the fracture toughness of the blades reaches the limit. As the test proceeds, the deformation degree of the blades continues to increase, and the gaps between the blades and the frame edge, as well as between the blades themselves, also increase accordingly, leading to an increase in the smoke leakage of the valve. Additionally, the decrease in the elastic force of the spring at low temperatures may also cause the smoke leakage of the valve to rise.  
2. The smoke leakage of the fire-fighting smoke and fire damper remains basically unchanged. This may be because after the blades deform to a certain extent, their tensile strength and elongation change slightly, keeping the state of the smoke and fire damper basically stable.  
3. The smoke leakage of the fire-fighting smoke and fire damper shows a downward trend. This may be because the deformation process of the blades of the normally closed smoke exhaust valve has not yet ended, and the fracture toughness of the blades has not reached the limit, resulting in a continued decrease in the smoke leakage of the valve.