Low pressure actuator for dry sprinkler system

An electro-pneumatic actuator for actuating a system triggered by a flow of a pressurized first fluid, said electro-pneumatic actuator being in fluid communication with a source of pressurized second fluid and a source of electrical current, said electro-pneumatic actuator comprising:

• a first pressure actuated valve controlling a flow of said pressurized first fluid through said actuator, said first valve having a first valve closing member with oppositely disposed sides both in fluid communication with said pressurized first fluid and being normally closed and preventing said flow, said first valve closing member opening to permit said flow when fluid pressure on one side of said first valve closing member exceeds fluid pressure on the opposite side of said first valve closing member, thereby actuating said system;
• a second pressure actuated valve controlling the fluid pressure on said opposite side of said first valve closing member, said second pressure actuated valve having a second valve closing member movable from a closed position which maintains fluid pressure on said opposite side of said first valve closing member, to an open position which releases fluid pressure from said opposite side of said first valve closing member, said second valve closing member having a side in fluid communication with said source of pressurized second fluid and being movable from said closed to said open position in response to a decrease in pressure of said pressurized second fluid;
• an electrically operated actuator engageable with said second valve closing member for maintaining it in said closed position, said electrically operated actuator adapted to respond to an electrical signal by releasing said second valve closing member from said closed position;
• and
• said second valve closing member moving into said open position only upon a concurrent pressure decrease of said second source of pressurized fluid and said electrical signal, thereby allowing said first valve closing member to move into said open position and permit flow of said pressurized fluid through said actuator, thereby triggering said system.

An electro-pneumatic actuator for controlling a flow of a pressurized first fluid in response to a decrease in pressure of a pressurized second fluid and an electrical signal, said actuator comprising:

• a first chamber having a first inlet orifice and an outlet orifice, said first chamber being in fluid communication with said first fluid through said first inlet orifice;
• a first flexible diaphragm positioned in said first chamber and being deflectable into engagement with said outlet orifice thereby preventing flow of said first fluid therethrough, said first diaphragm being deflectable out of engagement with said outlet orifice upon a decrease in pressure within said first chamber to allow flow of said first fluid through said outlet orifice;
• a second chamber;
• a pressure release orifice providing fluid communication between said first and second chambers;
• a second flexible diaphragm positioned within said second chamber and being deflectable into engagement with said pressure release orifice thereby preventing flow of said first fluid from said first chamber therethrough, said second diaphragm being deflectable out of engagement with said pressure release orifice to allow flow of said first fluid therethrough and thereby decrease pressure within said first chamber;
• a second inlet orifice providing fluid communication between said second fluid and said second chamber, pressure from said second fluid maintaining said second diaphragm engaged with said pressure release orifice;
• and
• an electrical activating means engaging said second diaphragm for normally maintaining said second diaphragm engaged with said pressure release orifice, said electrical activating means releasing said second diaphragm in response to said electrical signal, said second diaphragm deflecting out of engagement with said pressure release orifice in response to said electric signal and said decrease in pressure of said second fluid thereby decreasing pressure in said second and said first chambers and allowing said first diaphragm to deflect out of engagement with said outlet orifice in response thereto, thereby allowing said first fluid to flow through said outlet orifice.