What purpose does the drain (discharge pipe) on a safety relief valve serve?

The drain or discharge pipe on a safety relief valve primarily serves the purpose of preventing the accumulation of fluids that may lead to corrosion or other forms of deterioration. This pipe allows any discharged fluids, whether they be steam, vapor, or liquids, to exit the system in a controlled manner. By directing the discharge away from the valve and preventing moisture build-up, it helps to maintain the integrity of the valve and its surrounding components.

Ensuring that any discharged materials are safely conveyed away not only prolongs the life of the safety relief valve itself but also protects the entire boiler system from the damaging effects of corrosion that can occur in the presence of persistent dampness. In doing so, it contributes to the overall safety and reliability of the boiler system, making it an essential feature of boiler safety equipment.