Pneumatic flow control valve for fire suppression over pressure prevention

A controlled pressure release valve for preventing overpressure in a protected area upon delivery of gas, the valve comprising:

• a valve body having a gas inlet for connection to a gas container under pressure, a tapered valve seat, and a gas outlet for delivering gas to the protected area;
• a slidable spool housed in the valve body, the slidable spool formed of a cylindrical head portion that is adjacent to a tapered midsection that is adjacent to a cylindrical tail portion of larger diameter than the cylindrical head portion, and having a first end at the cylindrical head portion and a second end at the cylindrical tail portion, and the slidable spool being movable between a first position, wherein the tapered midsection is seated in the tapered valve seat, and a second position;
• a primary flow passage connecting the gas inlet and the gas outlet that is formed when the slidable spool moves away from the first position and the cylindrical head portion moves inside the tapered valve seat, wherein a cross-sectional area of the primary flow passage increases with lineal movement of the slidable spool as the cylindrical head portion lineally moves inside the tapered valve seat;
• a first chamber located adjacent the first end of the slidable spool, the first chamber having a first gas pressure;
• a second chamber located adjacent the second end of the slidable spool, the second chamber applying a second gas pressure to the slidable spool such that the second gas pressure biases the slidable pool toward the first position;
• a spring for biasing the slidable spool in the first position;
• a bleed passage connected to the second chamber;
• a valve actuator for actuating the valve by opening the bleed passage, wherein when the valve is actuated, the first and second chambers are in communication with the as inlet and the slidable spool is urged to the second position at a rate that is a function of a decreasing pneumatic gas pressure in at least one of the chambers;
• an internal passage through the slidable spool from the cylindrical head portion to the cylindrical tail portion fluidly coupling the first chamber and second chamber when the slidable spool is in the first position, and a needle valve slidably engagable with the internal passage;
• wherein the internal passage is a variable diameter internal passage and the needle valve is a variable diameter needle valve;
• wherein the variable diameter internal passage creates the controlled pressure differential between the first chamber and the second chamber as the variable diameter needle valve slidably engages the internal passage.

An open loop pneumatic flow control valve for controlled gas pressure release in a protected room, the open loop pneumatic flow control valve comprising:

• a valve body having a first end and a second end and a conical valve seat, and a gas inlet and a gas outlet;
• a slidable spool formed of a cylindrical head portion on one side of a conical midsection, the conical midsection adjacent to a cylindrical tail portion of larger diameter than the cylindrical head portion, the cylindrical tail portion at an opposite side of the conical midsection as the cylindrical head portion, and housed within the valve body and slidable between a first position, wherein the conical midsection is seated in the conical valve seat, and a second position, the slidable spool having a first end at the cylindrical head portion and a second end at the cylindrical tail portion;
• a spring for biasing the slidable spool towards the first position;
• a first chamber located between the first end of the valve body and the first end of the slidable spool, the cylindrical head portion being positioned between the first chamber and the tapered midsection, the cylindrical head portion defining a wall of the first chamber;
• a second chamber located between the second end of the slidable spool and the second end of the valve body, the second chamber having a gas pressure;
• a primary flow passage between the gas inlet and the gas outlet that is formed when the slidable spool moves away from the first position and the cylindrical head portion moves inside the conical valve seat, wherein the primary flow passage is closed when the slidable spool is in the first position, and wherein the primary flow passage is open when the slidable spool is in the second position;
• a bleed passage connected to the second chamber;
• and
• a valve actuator for actuating the valve by opening the bleed passage.