Chinese Professional Awwa C500 Nrs Metal Seated Gate Valve - M60A vacuum breaking valve – Convista

Specifications

Type: nuclear power vacuum breaking valve

Model: JNDX100-150P 150Lb

Nominal Diameter: DN 100-250

Applied to condenser system of a nuclear power station, it has negative pressure suction, positive pressure exhaust and liquid leakage prevention functions

.1.The vacuum breaking valve, an automatic valve, requires no additional drive when it is put into operation. At normal working state, the joint force of spring and medium exerted on valve disc presses the valve disc towards the valve seat to make the sealing surface cling and seal; when medium pressure drops to specified vacuum value (i.e. negative pressure up to setting pressure), spring is compressed, valve disc leaves valve seat, external air enters and system pressure boosts; when system pressure rises to working value, the spring pulls the valve disc towards the valve seat and sealing surface clings again to return to normal working state.

2.With its upper part guiding rod guided by the guiding seat, the float ball goes up when seawater level in the valve body cavity rises and the guiding rod seals the ventilation aperture in the guiding seat to prevent seawater leakage.

3.Function I negative pressure suction: when pressure of the vacuum system drops to set vacuum, thrust exerted at upper part of the valve disc is bigger than pre-tightening force from the spring and the valve disc opens rapidly to introduce external air into the valve body through air inlet of the valve seat and enter the vacuum system to boost pressure of the vacuum system gradually. When spring pre-tightening force is greater than thrust exerted at upper part of the valve disc, the valve disc blows back rapidly and external gas cannot enter the valve body. In this case, pressure of the vacuum system recovers to its normal value.

4.Function II positive pressure exhaust: when pressure value of the vacuum system is bigger than pressure of external air, connecting aperture of the guiding seat can discharge pressure in the valve body to external environment slowly to prevent excessive overpressure of the vacuum system from damaging the system equipment.

5.Function III liquid leakage prevention: in case of liquid in the vacuum system, when level raises gradually and contacts the float ball in the valve body, the float ball will rise with increasing level and guiding rod at upper part of the float ball will rise gradually to seal the connecting pore in the guiding seat to prevent liquid leakage in the system.