What is the difference between a safety valve built into a pump and a pipeline safety valve?

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The key difference between the safety valve built into the pump and the separate safety valve installed on the pipeline lies in their respective objects of protection and functional roles. Simply put, one is to protect the “pump” device, and the other is to protect the entire “pipeline system”. The pump is equipped with a safety valve: a form of \"self-protection\" for the equipment. The safety valve built into the pump is usually referred to as an internal pressure relief valve or pressure limiting valve. Protection target: Primarily aimed at the pump body itself. Core function: Its purpose is to prevent the pump from being damaged due to sudden pressure spikes during startup, shutdown, or operation. For example, when the outlet pipeline becomes suddenly blocked, it can open quickly, allowing the fluid to circulate inside the pump or over a short distance, thereby preventing the pump from damaging its motor or internal components due to pressure buildup. Limitations: These valves are typically designed for protection over short periods of time at low flow rates. It may be unable to handle continuous, high-flow overpressure conditions in the entire export pipeline system that result from prolonged blockages or improper operations. Pipe safety valve: The “final line of defense” of the system. A safety valve installed separately on the pump outlet pipe serves as a standard device for safe pressure relief in the system. Protected objects: What is protected is the entire export pipeline system, including pipes, flanges, valves, and all equipment downstream. Core function: Acting as the \"last line of defense\" for the system, it activates automatically when the pressure in the pipeline system exceeds a preset safe level, allowing a large amount of fluid to be discharged to a safe location (such as back into the inlet tank or a designated discharge system). This ensures that the pressure throughout the system remains within safe limits, preventing catastrophic incidents such as pipe bursts. Regulatory requirements: According to standards such as the \"Design Code for Petrochemical Enterprises\" (GB 50160), safety valves must be installed on the outlet pipes of positive displacement pumps (such as reciprocating pumps and gear pumps), unless it can be proven that the valves built into the pump itself are sufficient to protect the entire system. Key difference comparison: A common misconception is to think that \"having a valve on the pump means the system is protected.\" In fact, the built-in pressure relief valves in many pumps only provide short-term protection for the pump itself, and do not offer protection for the operation of the entire system. Therefore, in engineering design and safety inspections, if the valves built into the pump cannot be shown to have the capability to protect the entire piping system, an independent safety valve must be installed on the outlet pipeline to meet regulatory requirements and ensure system safety.