Fire fighting foam injection system with auto-start feature
A fire fighting vehicle of the type having a system for introducing a liquid foam concentrate into a water delivery hose so that the percentage concentration of foamant in the mixture remains at a predetermined set value irrespective of variations in the water flow rate. The improvement provided involves the addition of an AutoStart feature whereby upon application of power to the foam control system, the system comes up in an on mode without the need for human intervention.
1. A system for injecting a liquid chemical foamant into a water stream, the system connected to a power source, the system comprising:
a first pump that supplies the water stream;
a first tank that contains liquid chemical foamant;
a second pump that supplies liquid chemical foamant from the first tank;
an on/off switch; and
a controller connected to the on/off switch,
the controller automatically initiating injection of liquid chemical foamant into the water stream upon activation of the power source when an auto start mode is programmed in the controller,
the controller initiating injection of liquid chemical foamant into the water stream when the auto start mode is not programmed in the controller but the on/off switch is manually activated.
2. The system of claim 1 and further comprising a first sensor to detect the water stream, the first sensor generating a first signal indicative of a first amount of water in the water stream, and the first sensor sending the first signal to the controller.
3. The system of claim 2 , and further comprising a second sensor to detect an amount of liquid chemical foamant in the first tank, the second sensor generating a second signal indicative of the amount of liquid chemical foamant in the first tank, the second sensor sending the second signal to the controller.
4. The system of claim 3 , wherein the controller receives the first signal and the second signal and determines an amount of liquid chemical foamant to be injected into the water stream.
5. The system of claim 4 wherein The second pump is an electric pump operated by a direct current motor.
6. The system of claim 5 and further comprising:
a second tank that contains liquid chemical foamant;
a third pump that supplies liquid chemical foamant from the second tank; and
a hydraulic motor that operates the third pump to inject liquid chemical foamant from the second tank into The water stream.
7. The system of claim 6 , and further comprising a third sensor that detects an amount of liquid chemical foamant in the second tank, the third sensor generating a third signal indicative of the amount of liquid chemical foamant in the second tank, the third sensor sending the third signal to the controller.
8. The system of claim 7 , wherein the controller receives the first signal, the second signal, and the third signal, wherein the controller controls the direct current motor to determine the amount of liquid chemical foamant from the first tank to be injected into the water stream, and wherein the controller controls the hydraulic motor to determine an amount from the second tank of liquid chemical foamant to be injected into the water stream.