This valve is consisted of the hydraulic cylinder, plumb for urgent shut-up and hydraulic generating device, and in case of the regular condition, it is used as if if the general valve and in case of urgent condition, that is the time when the electric power is failed, and in case that valve shall be urgently cut due to all operating electric power, valve shall be cut urgently and in case that all hydraulic machin circuit is changing to circuit to be shut and it will be closing speed will be controlled by the flow control valve set in the influent device and the managing cost will be the same as influence type of valve. 
 

Featres 

1.To be used together the control valve and check valve in the previous time may be acted 2 kinds of roles with 1 unit of the urgent shut-up valve of the hydraulic butterfly valve 
2.In the time of urgency(electric fall), in case that valve will be shut-up urgently, it will be shut up automatically without foreign force like as the general valve, and make stop-up the reverse flow and as it is closing slowly about 90% of disk is closing position, when water hammer valve is urggently shut-up, the reverse flow will be bumped to disk and could be shut-up the reverse flow effectively without giving unreasonablness to valve and other machineries by the urgent raise of shok and pressure. 
3.It is structure to be possible the flow control caused by maintaining of intermediate way. 
4.since 2 units of valve will be alternated for 1 unit, the cost for facility will be decreased 
 

Function 

Non-return valve has equipped the following function 
1.Open the regular valve 
2.Close the regular valve 
3.Valve will be closed in the time of urgency
 (Closing speed will be done with 2nd stage and can adjust in the very site)  
4.Maintaining the mid way