Flooded Liquid Systems

Fig. 10-12 shows the floods of natural gas and liquid leg shut-off (top hot gas feed system. Here, the gas valve is used on both ends of the evaporator. It is a gas non-return valve. In defrost, usually closed-type solenoid pilot is energized. Hot gas pressure closes the gas valves. Streams of hot gas through the solenoid valves, pan coil, and in line check valve at the top of the evaporator. Here it purges evaporator liquid. The evaporator is discharged at a measured rate through the valve b., that was de-energized, and acts as a regulator during defrost.

At the end of the defrost cycle, the excess pressure will bleed from relief lines at a safe speed through voltage armature B. gas valves will not open evaporator separator until the gas pressure is almost down to the pressure in the system.

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