US 5,174,383 AGranted

Apparatus and method for controlling the introduction of chemical foamant into water stream in fire-fighting equipment

AssigneeHypro Corporation

InventorsRoger A. Haugen, Michael D. O'Dougherty

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Abstract

Fire-fighting apparatus and the method of using of same in which water from a supply source is adapted to be pumped at high pressure and predetermined flow rates through a fire hose and in which metered quantities of a chemical foamant are injected into the fire hose and mixed with the water stream to increase the effectiveness of the mixture as a fire extinguishant. A special purpose computer module is configured to monitor the flow rate of the water through the hose, the level of chemical foamant in a supply reservoir and the speed of the positive displacement pump used to inject the foamant. The computer then determines an appropriate speed for the pump and provides a closed-loop control signal to the pump's drive motor to maintain a desired chemical injection rate.

Claims8

Dependent claims

Apparatus for injecting a foamant chemical into a water stream used in extinguishing fires comprising, in combination:

(a) water supply means for normally delivering water at varying flow rates through a hose member;
(b) means for monitoring the flow of water through said hose member and producing an electrical signal related to the rate of water flow through said hose member;
(c) a supply tank for containing a supply of a liquid chemical foamant;
(d) positive displacement piston pump means having a variable stroke and, having an input port coupled to said supply tank, an output port and pump speed sensing means for sensing the speed at which said pump is being driven;
(e) means coupling said output port of said pump to said hose member;
(f) a variable speed electrical motor means for driving said pump means at a speed determined by a control signal applied thereto;
(g) computing means coupled to receive said electrical signal relating to flow, and a signal from said pump speed sensing means, said computing means determining the speed at which said motor should be driven to introduce a metered quantity of said chemical foamant into said hose member, depending on the rate of flow of water through said hose member;
(h) means connecting said computing means in driving relation to said motor means;
and
(i) calibration means for calibrating the actual pump output in relation to said metered quantity.

7 more elements

Dependencies are inferred from the claim text.