Apparatus for delivering compressed particulate solid fire fighting agent

A nozzle comprising:

• a plurality of stages including spaced compression throats;
• a primary flow path connecting at least two of said spaced compression throats;
• said at least two of said compression throats each having a substantially frusto conical taper decreasing in diameter in an axially downstream direction;
• and
• a secondary flow path operatively connected for allowing fluid back flow between said at least two spaced compression throats.

A nozzle comprising:

• a plurality of stages including spaced compression throats;
• a primary flow path connecting at least two of said spaced compression throats;
• a secondary flow path operatively connected for allowing fluid back flow between said at least two spaced compression throats;
• and
• means for allowing fluid flow through said secondary flow path and for substantially precluding passage of solid particulate material through said secondary flow path.

A nozzle comprising:

• a plurality of stages including spaced compression throats;
• a primary flow path connecting at least two of said spaced compression throats;
• a secondary flow path operatively connected for allowing fluid back flow between said at least two spaced compression throats;
• and
• a downstream one of said at least two of said compression throats having a smaller minimum diameter than the other of said at least two of said compression throats.

A nozzle comprising:

• a plurality of stages including spaced compression throats;
• at least two of said compression throats having a substantially frusto conical taper decreasing in diameter in an axially downstream direction;
• a primary flow path connecting said at least two of said spaced compression throats;
• and
• means for reducing pressure in at least one of said compression throats while substantially simultaneously increasing pressure in another one of said compression throats.

A nozzle comprising:

• a plurality of stages including spaced compression throats;
• a primary flow path connecting at least two of said spaced compression throats;
• a downstream one of said at least two of said compression throats having a smaller minimum diameter than the other of said at least two of said compression throats;
• and
• means for reducing pressure in at least one of said compression throats while substantially simultaneously increasing pressure in another one of said compression throats.

A nozzle for delivering compressed particulate solid material propelled in a high velocity gas stream, comprising:

• a valve communicating with a cylindrical first stage inlet passage of said nozzle for selectively allowing a high pressure gas flow with entrained solid particulate material and for controlling said flow through said nozzle;
• a first stage loading chamber disposed downstream of, adjacent to, and in fluid communication with said first stage inlet passage, said first stage loading chamber having a frusto conical taper increasing in diameter in an axially downstream direction;
• a first stage throat disposed downstream of, adjacent to, and in fluid communication with said first stage loading chamber, said first stage throat having a frusto conical taper decreasing in diameter in an axially downstream direction;
• a cylindrical second stage inlet passage disposed downstream of, adjacent to, and in fluid communication with said first stage throat;
• a first stage relief chamber disposed downstream of, adjacent to, and in fluid communication with said second stage inlet passage, said first stage relief chamber having a frusto conical taper increasing in diameter in an axially downstream direction;
• a cylindrical second stage loading chamber disposed downstream of, adjacent to, and in fluid communication with said first relief chamber;
• a second stage throat disposed downstream of, adjacent to, and in fluid communication with said second stage loading chamber, said second stage throat having a frusto conical taper decreasing in diameter in an axially downstream direction;
• a cylindrical third stage inlet passage disposed downstream of, adjacent to, and in fluid communication with said second stage throat;
• a second stage relief chamber disposed downstream of, adjacent to, and in fluid communication with said third stage inlet passage, said second stage relief chamber having a frusto conical taper increasing in diameter in an axially downstream direction;
• a third stage throat disposed downstream of, adjacent to, and in fluid communication with said second stage relief chamber, said third stage throat having a frusto conical taper decreasing in diameter in an axially downstream direction;
• a cylindrical discharge passage disposed downstream of, adjacent to, and in fluid communication with said third stage throat;
• a pressure feedback gas port connecting said second stage loading chamber to said first stage loading chamber;
• a screen in an inlet portion of said gas port adjacent said second stage loading chamber for allowing gas flow through said gas port while precluding flow of solid particulate material therethrough;
• a first adjustable spring check valve in said inlet portion of said gas port for allowing gas backflow through said gas port inlet only when pressure in said second stage loading chamber rises to a first adjustable limit value determined by said first check valve;
• and
• a second adjustable spring check valve in an outlet portion of said gas port for allowing gas backflow through said gas port outlet only when pressure in said gas port exceeds the sum of said first limit value, a second adjustable limit value determined by said second check valve, and the pressure in said first stage loading chamber.