Patent ID: 7185711

Claim:
A method of controlling the flow of fire suppressant, said method comprising: providing a preaction fire suppressant system, the fire suppressant system including a supply line and system piping, the system piping including at least one sprinkler and being supervised with air; providing an electrical detection and control system; detecting when a fire condition occurs and when the system piping experiences a loss of air pressure with the electrical detection system; providing a pneumatic detection and control system; detecting when the system piping experiences a loss of air pressure with the pneumatic detection and control system; during a powered state, controlling the delivery of fluid to the system piping using only the electrical detection and control system and delivering fire suppressant from the supply line to the system piping only in the event of a fire condition and a loss of air pressure in the system piping; during a non-powered state, controlling the delivery of fluid to the system piping using the pneumatic detection and control system and delivering fire suppressant from the supply line to the system piping only in the event of a loss of air pressure in the system piping; wherein said providing a preaction fire suppressant system includes providing a control valve and said controlling the delivery of fluid to the system piping includes opening or closing the control valve to control the flow of fire suppressant fluid; wherein said controlling the flow of fire suppressant includes maintaining the valve closed unless a fire condition and loss of air pressure in the system piping occurs during a powered state or unless a loss of air pressure in the system piping occurs during a non-powered state, said providing a valve includes providing a valve having an inlet, an outlet, a priming chamber, and a device that is operable to block the flow between the inlet and the outlet when the priming chamber is pressurized and operable to allow flow between the inlet and the outlet when pressure is released from the priming chamber, the valve including a priming line in fluid communication with the supply line and the priming chamber, and said maintaining the valve closed includes pressurizing the priming chamber with the priming line whereby the valve has a normally closed condition; and when in the powered state said controlling the flow of fire suppressant includes isolating the pneumatic detection and control system from the control valve during a loss of air pressure in the system piping and a fire condition.