When the system pressure is too high, the safety valve can automatically open the pressure relief, and when the system pressure ( ) can automatically close to prevent the medium from continuing to leak.

The upper and lower hand valves of the safety valve should be ( ) during the steam opening process.

The most widely used automatic decompressionvalve is ( ).

The automatic opening and closing of the safety valve is determined according to the ( ) change of the system.

Check valves are classified by ( ) and are available as lift and swing.

The valve that prevents the reverse backflow action of the medium is ( ).

Lift check valves generally have flaps of ( ).

The body of a lift check valve is generally the same as the body of ( ).

The medium used for the heating furnace shock soot blower is ( ).

The action of the furnace soot blower, wrong is ( ).

The action of the furnace soot blower, correct is ( ).

The main function of the reheating furnace soot blower is ( ).

The following belong to the heating furnace chimney action is ( ).

The higher the heating furnace chimney, the suction ( ).

The most important factor that determines the suction force of the furnace chimney is ( ).