What valve type must be installed in the discharge pipe of a jockey pump?

The correct choice of a check valve for installation in the discharge pipe of a jockey pump is crucial for preventing backflow in the system. A jockey pump is typically used in fire protection systems to maintain pressure within the piping network by supplementing the main pump's operation.

When the jockey pump operates, it pressurizes the system and delivers water to the fire protection network. However, if there’s a sudden drop in pressure or if the main fire pump activates, there is a risk of water flowing back towards the jockey pump. The check valve is designed to allow flow in only one direction—outward from the pump—thus ensuring that water does not return to the jockey pump when the pressure in the system changes. This function is essential for maintaining the efficiency and reliability of the fire protection system.

Other valve types serve different purposes and are not suitable for this specific application. A relief valve, for instance, is used to prevent overpressure conditions in the system, while an indicating valve is meant for visual indication of the valve's position. A reducing valve regulates pressure but does not address the prevention of backflow. Therefore, the use of a check valve is the appropriate choice for maintaining pressure integrity in the discharge line of a jockey pump.