Check Valve and a swing check valve?

The swing check valve uses a flapper that 'swings' off the seat to let forward flow and then swings back onto the core when the flow is stopped. In contrast, a spring-loaded check valve combines a spring to help close the Valve.

FlowBiz Pressure Seal Swing Check Valve:

FlowBiz Pressure Seal Check Valves are ideal for high-pressure steam, liquid, catalytic reformers, hydrocrackers, and other demanding services. These valves are unidirectional and slow flow from the opposite direction, best suited for medium velocity needs. Check valves are usually designed for horizontal flow conditions. Still, they can also be established in a vertical pipeline, but the flow shall be upwards and under the disc in a vertical channel.

The necessary concept of pressure seal valves is that the initial cover pull-up bolts tighten the cover, sealing the pressure seal gasket to the body. Then, the system pressure assists in creating more force to close the gasket. Hence, as system pressure increases, the potential for leakage through the body/bonnet joint decreases.

Pressure Seal Valves are planned for high-pressure and high-temperature applications for all fluids, except where strict coking may appear. Because of their design and construction materials, Pressure Seal Valves are perfect for nuclear steam generating groups, thermal power plants, and industrial/chemical plants. They offer efficiency in flow passage and sealing, weight savings, ease of installation, and simplicity in maintenance.