Scheme of tank fire safety system

Dry powder fire extinguishing device

The top of the tank is equipped with skid mounted dry powder fire extinguishing device, and the vent of the exhalation valve is equipped with explosion-proof three frequency infrared flame detector and armored platinum thermal resistance thermometer. When the temperature of the diffuser reaches the set alarm temperature (200 ℃) and the flame detector sends an alarm signal, the FGS system outputs a switch signal to control the dry powder electromagnetic starter to open the dry powder fire extinguishing device and spray dry powder to put out the fire. Dry powder fire extinguishing system has three starting modes: automatic control, manual control and mechanical emergency operation.

Local manual one button start mode:

Press the system start button on the control cabinet (without delay of 30s) and the system will automatically start the solenoid valve of the starting cylinder. At this time, the dry powder tank will start to charge. When the pressure in the tank rises to the working pressure of the dry powder system, the rupture disc on the tank will explode automatically, and the dry powder will be ejected from the blast hole and transported to the terminal fire extinguishing equipment through the dry powder pipe network.

Mechanical emergency start mode:

When the control cabinet cannot start the starting bottle, the emergency device on the dry powder skid can be pulled. Mechanical emergency start mode of tank bottom: one set of main and standby dry powder emergency start is set at the tank bottom. When the control cabinet cannot start the bottle, the mechanical emergency start can be set at the tank bottom.

Remote auto start:

If the fire signal is received from the central control room, start the dry powder fire extinguishing system after 10 seconds delay. If the command of start button in central control room is received, the dry powder fire extinguishing system will not be delayed. If the emergency stop button in the central control room is received, the dry powder fire extinguishing system will not be delayed (this function is only effective when the control cabinet receives the fire signal in the central control room and starts the dry powder fire extinguishing system after 10 seconds delay).

A pressure switch is installed at the powder outlet of the dry powder skid. When the main dry powder fire extinguishing system starts, the dry powder pressure will be detected. When the pressure is not detected, the main dry powder fire extinguishing system fails to start, and the control cabinet will automatically start the standby dry powder fire extinguishing system.

(1) The protection grade of the explosion-proof control box is IP65, and the explosion-proof grade is Exd Ⅱ BT4;

(2) Technical requirements of explosion-proof control box and s local terminal line: the system includes: automatic start mode interlocking with flame detector, manual start mode outside cofferdam and emergency start mode of tank bottom machinery.

When the system receives the automatic or manual opening signal, the signal is sent to the explosion-proof control box of the dry powder equipment. The solenoid valve of the starting bottle of the dry powder equipment is opened to drive the bottle head valve to open. The high-pressure nitrogen is filled into the dry powder tank through the one-way valve and pressure reducing valve, and mixed with the dry powder in the tank to pressurize. The fluidized dry powder and drive gas mixture breaks through the diaphragm set at the outlet of the dry powder tank, It acts on the vent pipe through dry powder pipe and nozzle.