Electronically Controlled Direct Injection Foam Delivery System and Method of Regulating Flow of Foam into Water Stream Based on Conductivity Measure
First Claim
1. A unit of fire fighting equipment having a direct injection foam delivery system, comprising:
- a water pump for pumping water through a pipe;
a foam pump coupled to the pipe for mixing foam with the water and producing a mixture;
a control unit for controlling the foam pump;
a first conductivity sensor coupled in-line with the pipe for monitoring conductivity of the mixture and providing a mixture conductivity signal to the control unit; and
a second conductivity sensor coupled in-line with the pipe for monitoring conductivity of the water and providing a water conductivity signal to the control unit, wherein the control unit uses a difference between the mixture conductivity signal and the water conductivity signal to regulate the foam pump.
2 Assignments
0 Petitions
Accused Products
Abstract
Fire fighting equipment uses an electronically controlled direct injection foam delivery system. A water pump pumps water through a pipe. A foam pump pumps foam into a mixing chamber within the pipe to produce a water-foam mixture. A microprocessor-based control unit controls the water pump and foam pump. A conductivity sensor is coupled in-line with the pipe for monitoring conductivity of the mixture and providing a feedback signal to the control unit to regulate the foam pump. A speed sensor monitors the foam usage. The conductivity sensor uses stainless steel plates positioned in the flow stream of the pipe for measuring conductivity of the mixture. A second conductivity sensor monitors conductivity of the water and provides a feedback signal to the control unit. An interface circuit generates a voltage having dual polarity and a fifty percent duty cycle for the conductivity sensors.
37 Citations
27 Claims
-
1. A unit of fire fighting equipment having a direct injection foam delivery system, comprising:
-
a water pump for pumping water through a pipe;
a foam pump coupled to the pipe for mixing foam with the water and producing a mixture;
a control unit for controlling the foam pump;
a first conductivity sensor coupled in-line with the pipe for monitoring conductivity of the mixture and providing a mixture conductivity signal to the control unit; and
a second conductivity sensor coupled in-line with the pipe for monitoring conductivity of the water and providing a water conductivity signal to the control unit, wherein the control unit uses a difference between the mixture conductivity signal and the water conductivity signal to regulate the foam pump. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A mixing system, comprising:
-
a pump for directing a chemical agent into a pipe for mixing with a liquid and producing a mixture;
a control unit for controlling the pump;
a first conductivity sensor coupled to the pipe for monitoring conductivity of the mixture and providing a mixture conductivity signal to the control unit; and
a second conductivity sensor coupled in-line with the pipe for monitoring conductivity of the liquid and providing a liquid conductivity signal to the control unit, wherein the control unit regulates the pump in response to the mixture conductivity signal and the liquid conductivity signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A system for mixing first and second fluids, comprising:
-
a conduit for transporting the first under pressure, wherein the second fluid is injected into the conduit for producing a mixture of the first and second fluids;
a control unit for controlling a flow rate of the second fluid;
a first conductivity sensor for monitoring conductivity of the mixture and providing a mixture conductivity signal to the control unit; and
a second conductivity sensor coupled in-line with the conduit for monitoring conductivity of the first fluid and providing a first fluid conductivity signal to the control unit, wherein the control unit controls the flow rate of the second fluid in response to the mixture conductivity signal and the first fluid conductivity signal. - View Dependent Claims (20, 21, 22, 23)
-
-
24. A method of regulating percent concentration of first and second fluids, comprising:
-
transporting a first fluid through a conduit under pressure;
mixing a second fluid with the first fluid to produce a mixture;
sensing conductivity of the first fluid;
sensing conductivity of the mixture; and
regulating flow of the second fluid in response to the sensed conductivity of the first fluid and mixture. - View Dependent Claims (25, 26, 27)
-
Specification