Low Lift Safety Valve

The A41/47 Low-lift safety valves are commonly used safety protection devices in the industrial field:

Structural Features

• Valve Disc Opening Form: The A41/47 series safety valves adopt a Low-lift design. The opening height of the valve disc is relatively small, generally ranging from 1/40 to 1/20 of the throat diameter. This opening method results in a relatively small flow rate when the safety valve discharges the medium, making it suitable for applications where a high discharge speed is not required.

• Spring-loaded Structure: These series of safety valves use a structure where the spring acts directly on the valve disc. The preload of the spring can be adjusted through an adjusting nut to set the opening pressure of the safety valve. When the system pressure exceeds the set value, the medium pressure acts on the lower part of the valve disc, overcoming the spring force and causing the valve disc to open, thus achieving the pressure relief function.

• Sealing Structure: The A41/47 Low-lift safety valves usually adopt a flat or conical sealing structure to ensure effective prevention of medium leakage when the valve is closed. The sealing surfaces are finely ground, featuring good sealing performance and wear resistance, which can guarantee the reliability of the safety valve during long-term use.

• Multiple Connection Methods: These series of safety valves offer multiple connection methods, commonly including flange connections and threaded connections, to meet the installation requirements of different users. The flange connection method is suitable for large-diameter, high-pressure pipeline systems, with advantages such as firm connection and reliable sealing. The threaded connection is suitable for small-diameter pipelines and is convenient and quick to install.

Working Principle

• Normal Working State: During normal system operation, the medium pressure is lower than the set pressure of the safety valve. The spring force presses the valve disc tightly against the valve seat, and the safety valve remains closed to prevent medium leakage.

• Opening under Overpressure: When the system pressure rises above the set pressure of the safety valve due to certain reasons, the upward force generated by the medium pressure acting on the lower part of the valve disc is greater than the preload of the spring. The valve disc starts to move upward, leaving the valve seat and forming a small opening gap. The medium is discharged from the system through this gap, thereby reducing the system pressure.

• Reseating and Closing: When the system pressure drops below the reseating pressure of the safety valve, the spring force pushes the valve disc back to the valve seat, closing the safety valve and preventing further medium discharge. The reseating pressure of the safety valve is generally lower than the set pressure to ensure stable system operation within the normal pressure range and avoid frequent opening and closing.

Scope of Application

• Medium Types: The A41/47 Low-lift safety valves are suitable for a variety of media, such as general media like air, water, steam, and oil products. For some highly corrosive media, safety valves made of corresponding materials can be selected according to specific circumstances. For example, models such as A41Y - 16P and A47Y - 16P made of stainless steel can meet the corrosion resistance requirements.

• Pressure Range: The nominal pressure range of these series of safety valves is relatively wide, generally ranging from PN1.6 to PN40, which can meet the requirements of systems with different pressure levels. For example, in some low-pressure steam boilers and hot water systems, A41/47 safety valves with lower nominal pressures can be selected. In some medium- and high-pressure industrial pipeline systems, models with higher nominal pressures are required.

• Temperature Range: Different materials and models of A41/47 Low-lift safety valves have different applicable temperature ranges. Generally, safety valves made of ordinary carbon steel are suitable for media with a temperature not exceeding 425°C, while those made of stainless steel can be used for media at higher temperatures. For example, models such as A41Y - 16P and A47Y - 16P are suitable for corrosive media with a temperature not exceeding 200°C.

Features and Advantages

• Simple Structure: The A41/47 Low-lift safety valves have a relatively simple structure, mainly consisting of components such as the valve body, valve seat, valve disc, spring, and adjusting nut. There are no complex transmission mechanisms, so the manufacturing and maintenance costs are relatively low, and they are easy to operate and manage.

• High Reliability: These series of safety valves have undergone strict quality inspections and performance tests, featuring good sealing performance and stability. Their spring-loaded structure ensures that the opening pressure and reseating pressure of the safety valve remain stable during long-term use, effectively protecting the system safety.

• Convenient Adjustment: By adjusting the preload of the spring, the opening pressure of the safety valve can be easily adjusted to meet the working pressure requirements of different systems. In addition, some safety valves are equipped with an adjusting ring, which can further fine-tune the discharge pressure and reseating pressure, improving the performance of the safety valve.

• Wide Application: Due to their wide range of applicable media, pressures, and temperatures, as well as their simple and reliable structure, the A41/47 Low-lift safety valves are widely used in many industrial fields such as petroleum, chemical, power, metallurgy, and pharmaceuticals. They are important devices for ensuring the safe operation of industrial systems.

Selection Points

• Selection Based on System Parameters: First, select the appropriate model and specification of the safety valve according to the system's working pressure, temperature, medium, and other parameters. Ensure that the nominal pressure, applicable temperature range, and medium compatibility of the safety valve can meet the system requirements to guarantee the reliable operation of the safety valve under normal working conditions.

• Calculation of Safety Discharge Capacity: Calculate the required safety discharge capacity of the system based on the system's process requirements and possible overpressure situations. Then select a safety valve with the corresponding discharge capacity to ensure that the excess medium can be discharged in a timely and effective manner during overpressure, preventing safety accidents caused by excessive system pressure.

• Consideration of Installation Space and Connection Method: During the selection process, also consider whether the installation space and connection method of the safety valve are compatible with the system pipeline. Select the appropriate connection method, such as flange connection or threaded connection, according to the on-site installation conditions, and ensure that the external dimensions of the safety valve can allow for normal installation and operation within the given installation space.