The Fixed Position Breathing Valve is commonly used in low-pressure straight-through pipelines, where its sealing performance relies entirely on the fit between the plug and the body. The sealing surface is tightened by screwing the nut at the bottom. It is generally used for PN≤0.6Mpa.
The stuffing gland breathing valve is sealed by pressing the stuffing gland, which results in better sealing performance due to the presence of the gland. Typically, such breathing valves have a gland cover, allowing the plug to remain within the valve body, thereby reducing one potential leak path for the working medium. These valves are widely used for pressures up to PN ≤ 1 MPa.
The Self-Sealing Breathing Valve is designed to achieve a tight seal between the plug and the body by utilizing the pressure of the medium itself. The small end of the plug extends upward out of the body, and the medium enters the large end of the plug through a small hole at the inlet, pressing the plug tightly upwards. This structure is generally used for air mediums.
The oil-sealed breathing valve's application range continues to expand, leading to the emergence of oil-sealed breathing valves with forced lubrication. The forced lubrication creates an oil film between the plug and the sealing surface of the body, resulting in improved sealing performance, easier operation, and protection against damage to the sealing surfaces.