Foam fire fighting apparatus

An apparatus for making foam using a foam concentrate, a liquid and a vapor, said apparatus having a liquid inlet, a vapor inlet, foam concentrate inlet and a foam outlet and further comprising:

• a primary tubular member defining a mixing chamber therein;
• eductor means substantially within said mixing chamber for drawing in foam concentrate while mixing said foam concentrate with a portion of the liquid delivered to said liquid inlet;
• a secondary tubular member defining an unobstructed foam chamber therein;
• said foam chamber having means for providing a backpressure adjacent its foam outlet by promoting turbulence in said foam chamber and the creation of a substantially uniform bubble size;
• said secondary tubular member being in flow communication with said primary tubular member at one end via a flow passage therebetween, and having said foam outlet at its opposite end;
• said eductor means extending through said flow passage into said secondary tubular member, thereby defining an annulus in said flow passage to allow a portion of the liquid in said primary tubular member to by-pass said eductor means and enter said secondary tubular member and thereby form a combined liquid stream;
• said mixing chamber providing minimal resistance to flow resulting from internal projections therein, of liquid by-passing said eductor means, said resistance being created substantially entirely by said eductor means and its support;
• vapor induction means with said secondary tubular member for allowing vapor to be drawn into said secondary tubular member to mix with a combined liquid stream from said annulus and said eductor means to create foam in said secondary tubular member;
• and
• a tip segment extending from said foam outlet and located outwardly of said means for providing a backpressure to assist in directing the flow of foam created by the apparatus, said tip segment having an unobstructed flow path over its entire length.

A foam fire fighting system for storage tanks comprising:

• a foam making assembly having a liquid inlet, a foam concentrate inlet, and a foam outlet line;
• means for delivering a liquid under pressure to said liquid inlet;
• means for delivering foam concentrate to said foam concentrate inlet;
• said foam making assembly further comprising:
• a primary tubular member having a longitudinal axis and defining a mixing chamber therein;
• eductor means substantially within said mixing chamber for drawing foam concentrate from said foam concentrate delivery means while mixing said foam concentrate with a portion of the liquid delivered to said liquid inlet;
• a secondary tubular member defining a foam chamber therein;
• said secondary tubular member having one end in flow communication with one end of said primary tubular member via a flow passage therebetween, and said secondary tubular member having a foam outlet at its opposite end from said primary tubular member;
• said foam chamber of said secondary tubular member being unobstructed from said one end to said opposite end;
• said foam chamber having means for providing a backpressure adjacent said foam outlet thereby promoting turbulence in said foam chamber and a creation of a substantially uniform bubble size;
• said eductor means extending through said flow passage into said secondary tubular member, thereby defining an annulus in said flow passage to allow a portion of the liquid in said primary tubular member to by-pass said eductor means and enter said tubular member;
• vapor induction means with said secondary tubular member for allowing vapor to be drawn into said secondary tubular member to mix with a combined liquid stream from said annulus and said eductor means to create foam in said secondary tubular member;
• valve means mounted in said foam outlet line;
• said line extending from said foam outlet and being unobstructed over its entire length when said valve means is open;
• said primary tubular member further includes a plurality of vanes extending radially from the longitudinal axis of said primary tubular member;
• said eductor means further includes a plurality of liquid inlets in flow communication with each other to insure continued liquid flow into said eductor means if any of said inlets plug with debris carried by the liquid flowing into said mixing chamber;
• said vapor induction means further includes a plurality of openings in said secondary tubular member circumferentially spaced in a plane perpendicular to the longitudinal axis of said secondary tubular member adjacent the outlet of said eductor means;
• said flow passage has an increasing taper in the direction from said primary to said secondary tubular member, whereupon the liquid flowing through said annulus is directed past said circumferentially spaced openings in said secondary tubular member before impinging on a wall of said foam chamber;
• said flow passage has a taper of about five degrees;
• and
• the outlet of said eductor means extending into said foam chamber has an externally beveled tip ranging from thirty to forty-five degrees measured from the longitudinal axis of said foam chamber.

An apparatus for making foam using a foam concentrate a liquid and a vapor, said apparatus having a liquid inlet, a vapor inlet, foam concentrate inlet and a foam outlet and further comprising:

• a primary tubular member defining a mixing chamber therein;
• eductor means substantially within aid mixing chamber for drawing in foam concentrate while mixing said foam concentrate with a portion of the liquid delivered to said liquid inlet;
• a secondary tubular member defining an unobstructed foam chamber therein;
• said foam chamber having means for providing a backpressure adjacent its foam outlet thereby promoting turbulence in said foam chamber and the creation of a substantially uniform bubble size;
• said secondary tubular member in flow communication with said primary tubular member at one end via a flow passage therebetween, and having said foam outlet at its opposite end;
• said eductor means extending through said flow passage into said secondary tubular member, thereby defining an annulus in said flow passage to allow a portion of the liquid in said primary tubular member to by-pass said eductor means and enter said secondary tubular member;
• vapor induction means with said secondary tubular member for allowing vapor to be drawn into said secondary tubular member to mix with the combined liquid stream from said annulus and said stream from said eductor means to create foam in said secondary tubular member;
• a tip segment extending from said foam outlet to assist in directing the flow of foam created by the apparatus, said tip segment having an unobstructed flow path over its entire length;
• said eductor means further includes a plurality of liquid inlets in flow communication with each other to insure continued liquid flow into said eductor means if any of said inlets plug with debris carried by the liquid flowing into said mixing chamber;
• said vapor induction means further includes a plurality of openings in said secondary tubular member circumferentially spaced in a plane perpendicular to the longitudinal axis of said secondary tubular member adjacent the outlet of said eductor means;
• said flow passage has an increasing taper in the direction from said primary to said secondary tubular member, whereupon the liquid flowing through said annulus is directed past said circumferentially spaced openings in said secondary tubular member before impinging on a wall of said foam chamber;
• said flow passage has a taper of about five degrees;
• and
• said outlet of said eductor means extending into said foam chamber has an externally beveled tip ranging from thirty to forty-five degrees measured from the longitudinal axis of said foam chamber.

A foam fire fighting system, comprising:

• a foam making assembly having a liquid inlet, a foam concentrate inlet, and a foam outlet line;
• means for delivering a liquid under pressure to said liquid inlet;
• means for delivering foam concentrate to said foam concentrate inlet;
• said foam making assembly further comprising:
• a primary tubular member having a longitudinal axis and an inlet and an outlet and defining a mixing chamber therebetween;
• eductor means supported and disposed substantially within said mixing chamber for creating a reduced pressure in said primary tubular member for drawing foam concentrate from said foam concentrate delivery means while mixing said foam concentrate with a portion of the liquid delivered to said liquid inlet;
• a secondary tubular member defining a foam chamber therein;
• said secondary tubular member having an internal surface and having one end in flow communication with said outlet of said primary tubular member via a flow passage therebetween, and said secondary tubular member having a foam outlet at its opposite end from said primary tubular member;
• said primary tubular member being substantially unobstructed throughout its length for providing essentially laminar flow of the liquid therethrough from said inlet to said outlet;
• said eductor means extending through said flow passage into said secondary tubular member, thereby defining an annulus in said flow passage to allow a portion of the liquid in said primary tubular member to by-pass said eductor means and enter said secondary tubular member;
• vapor induction means with said secondary tubular member for allowing vapor to be drawn into said secondary tubular member to mix with the combined liquid stream from said annulus and said stream from said eductor means with turbulence to create foam in said secondary tubular member;
• and
• said eductor means including a tube which has a tip end disposed in said secondary tubular member and which is externally beveled at an angle between about thirty and forty-five degrees relative to the longitudinal axis of said tube.