CAN COST LESS THAN $3000
IF DO-IT-YOURSELF PROJECT.
The Spray Hose (US 9,561,393, Shoap) can protect a home from wildfire. Many homes are ignited by blowing embers. The Spray Hose creates a high wall of water that can help prevent embers from igniting fires on and around the home.When a fire is approaching a home, the homeowner should evacuate. If the homeowner starts a spray system before leaving, the water supply will probably be depleted before the fire arrives. Water sprayed before the fire arrives has some value in wetting the ground and the walls of the home. However, the water may dry up before the fire arrives.
The system shown in the FIG 1 is a low cost method of automatically starting the spray system when the fire arrives. This system allows the homeowner to quickly arm the system and then evacuate.The system uses a gasoline pump with a hand pulled starter because of its low cost. When ordered to evacuate, the homeowner puts the choke in the start position and pulls the starter cord. Once the engine starts, the choke is moved to the run position. The throttle is moved from the start position to the highest speed position.
There are pumps that can be remotely started, but they are very expensive. If the pump is fueled by gasoline, the automatic adjustment of the choke and throttle must be done by a computer chip and small motors.
Diesel pumps do not need a choke and can be more easily auto-started, but they are expensive.
FIG 1 shows the components of the Low Cost Automatic Spray System.
A water tank supplies water to a gasoline pump which delivers water to an electric 2-Port Valve, and also back to the water tank through a Pressure Relief Valve. The 2-Port Valve can direct water to a Spray Hose. The electric 2-Port Valve is controlled by thermistors or other low cost fire detectors that are placed on the outer walls of the home. A thermistor changes its electrical resistance when the temperature changes.
Fig 2 shows the case where the homeowner starts the pump, and when NO fire is nearby, the 2-Port Valve is normally in a condition where the water is NOT being sent to the Spray Hose. The water is pumped thru the Pressure Relief Valve and returns to the water tank, The PVC pipe used to return the water has a small diameter and little water flows back to the tank. This causes the pressure out of the pump to be high, and the Pressure Relief Valve allows the water to pass thru and reenter the water tank.
The gasoline tank on the recommended pump allows the pump to run for
Since the fire may not arrive for many hours, a larger gasoline supply may be added. I could not find a place to purchase such a tank for the recommended pump, but there are many YouTube videos that show how to build one.
When the fire comes close enough to be detected by a thermistor, or other fire sensor, the 2-Port Valve opens and water flows into the spray hose. This is shown in the Fig 3. The feedback to the Water Tank has been removed in Fig 3 because when the flow increases significantly into the Spray Hose, the pressure out of the pump drops enough for the Pressure Relief Valve to close, and all of the water is sent into the Spray Hose.
A low water detect signal to the Control Circuit closes the 2-Port Valve and all of the water goes back into the water tank. This is done so that the pump does not run without any water. This is necessary to avoid damage from overheating to the pump volute parts.
The low water detect signal can be used to turn off the pump by opening the pump ignition circuit.
This valve is a quality product at a low cost. The version I use is a 12 volt DC unit. It has 2 inch NPS threads which can easily attach to 2 inch PVC pipe.
The air freight from China costs more than the valve.
I will be ordering a number of valves from Covna that will be sent to me via ship. The per unit shipping cost will be approximately $15.
IF YOU EXPECT TO BUY SOME VALVES FROM ME, PLEASE TELL ME.
The spring on the pressure relief valve should be set so that the valve opens when the Ball Valve is shut. The pressure relief valve should close when the Ball Valve opens and allows the Spray to begin.