The A42/48 full-lift safety valves are commonly used industrial safety valves. Here is a detailed introduction:
A42 Series: It features a full-closed structure without a handle. This structure can effectively prevent medium leakage, making it suitable for working environments with strict leakage requirements.
A48 Series: It has an open-window structure with a handle. The open-window structure facilitates heat dissipation, reducing the impact of high-temperature media on internal components such as springs. It is suitable for working conditions involving high-temperature media.
Both the A42 and A48 full-lift safety valves are spring direct-loaded types, and their working principles are the same as those of general full-lift safety valves. When the pressure of the medium in the equipment or pipeline exceeds the set pressure of the safety valve, the force exerted by the medium on the lower part of the valve disc overcomes the spring force, causing the valve disc to open rapidly to the full-lift state. A large amount of medium is discharged through the safety valve, thereby reducing the system pressure. When the system pressure drops below the reseating pressure of the safety valve, the spring force makes the valve disc reseat, closing the valve and preventing further medium discharge.
A42Y - 16C to 40: It is suitable for equipment and pipelines handling media such as air and petroleum gas with a working temperature ≤ 300°C.
A42Y - 16P to 40P: It is suitable for equipment and pipelines handling corrosive gaseous media with a working temperature ≤ 200°C.
A48 Series: It is commonly used in equipment or pipelines handling high-temperature steam and other media, such as steam boilers and steam pipelines in industries like chemical and power. It serves as an overpressure protection device to ensure the safe operation of equipment and pipelines within the specified pressure range.
Full-lift Discharge: The valve disc has a large opening height, enabling it to discharge a large amount of medium in a short time. This effectively protects the safety of equipment and pipelines and is suitable for situations requiring rapid pressure relief, such as high-pressure vessels and large-scale reaction kettles.
Adjustment Function: Usually equipped with an adjusting ring, it can adjust the reseating pressure and discharge pressure to meet different working pressure and working condition requirements, ensuring the stable and reliable performance of the safety valve.
High Precision: It has a small deviation in the set pressure and can accurately open at the set pressure. This ensures timely protection of the equipment when overpressure occurs and avoids false opening or failure to open due to pressure fluctuations.
Selection Based on Medium Characteristics: For corrosive media, safety valves made of corresponding materials should be selected, such as the stainless-steel model A42Y - 16P. For high-temperature media, the temperature resistance of the safety valve should be considered. For example, the A48 series is suitable for high-temperature steam.
Calculation of Safety Discharge Capacity: The discharge capacity of the safety valve must be greater than the safety discharge capacity of the container to ensure timely and effective discharge of excess medium during overpressure and prevent the pressure from continuing to rise.
Consideration of Working Pressure and Temperature: When selecting a safety valve, ensure that its rated pressure and temperature range can meet the working pressure and temperature requirements of the equipment or pipeline, avoiding safety valve failure due to excessive pressure or temperature.
