Swamp coolers
collect and breed all kinds of bacteria and mold in the water. As
the cooler operates, these organisms can travel into your home and
cause a variety of health problems. Chemicals can be added to the
water to kill bacteria, mold and algae, but can be difficult to
maintain.
It's be a proven fact that Bacteria, Molds and Algae can be killed by introducing copper and zinc ions into the water. Silver works very well to, but may be difficult for the home owner to construct a proper electrode. We will just be using copper and zinc ions for our project. Several companies make and sell such devices to release these ions into the water of swimming pools, hot tubs, water coolers and storage tanks. Generating these ions are quite simple to do.
All that is needed is to connect a suitable electrode of these metals to a DC power supply. The following shows how I made a simple ion generator.
For the emitting electrode I used a brass pipe found in a hardware store. Most brass material is composed of 60 % copper and 40% zinc.
For the DC power supply, only a milliamp (1/1000 th of an amp) is required. I used a 2 watt 62K resistor in series with an 1N4005 diode and connected it to a line cord for plugging into the 120 AC outlet that powers the swamp cooler pump. Heat shrink tubing covers the assembly. The diode forms a half wave rectifier and the resistor limits the short circuit current to about a milliamp. Ions are generated on the positive half of the line frequency and travel off the electrode as pulses of 60 hertz.
The resistor value determines how many ions are generated. It operates like the principle of electroplating, but in reverse. We are "unplating" the zinc and copper from the brass pipe. Larger values of resistance will reduce the number of ions made. The value can be adjusted by adding a second resistor in series, a method I will show later.
The two main components used. A diode and a resistor.
Mount the diode and resistor on a piece of perf board. The band (cathode) of the diode should be toward the left. The direction sets the polarity.
Bend the leads as shown.
Don't forget to solder the joint between the resistor and the diode.
Cut off the plug end of a line cord. Cut the green ground wire and the white neutral a little shorter that the black (120V hot end).
Strip only the black end and pre-tin the end with solder.
Solder the black lead to the resistor end of the assembly.
Solder to the diode end a length of wire with a quick disconnect female connector.
Check your wiring and cover with two layers of heat shrink tubing. I used "sticky shrink" ( the type with hot melt glue) on the final layer.
The sticky shrink makes a damp proof assembly possible.
The finished Ion Generator
Attach a length of wire to the "electrode" with a pipe clamp. Use a heavy gauge wire because this will errode away in time too.
Attach a male quick disconnect connector to the wire.
The completed Ion Generator, ready to install.
Measured current of .89 milliamps with a meter connected in series with the device. Open circuit voltage is about 60 volts.
WARNING
Use care when handling the device when on. Remember the device is connected to the mains.
Current is limited, but a small shock may be felt if you touch the electrode, especially if it is wet.
This project should only be attemped with those with experience in electronic project building.
TO BE CONTINUED...
It's be a proven fact that Bacteria, Molds and Algae can be killed by introducing copper and zinc ions into the water. Silver works very well to, but may be difficult for the home owner to construct a proper electrode. We will just be using copper and zinc ions for our project. Several companies make and sell such devices to release these ions into the water of swimming pools, hot tubs, water coolers and storage tanks. Generating these ions are quite simple to do.
All that is needed is to connect a suitable electrode of these metals to a DC power supply. The following shows how I made a simple ion generator.
For the emitting electrode I used a brass pipe found in a hardware store. Most brass material is composed of 60 % copper and 40% zinc.
For the DC power supply, only a milliamp (1/1000 th of an amp) is required. I used a 2 watt 62K resistor in series with an 1N4005 diode and connected it to a line cord for plugging into the 120 AC outlet that powers the swamp cooler pump. Heat shrink tubing covers the assembly. The diode forms a half wave rectifier and the resistor limits the short circuit current to about a milliamp. Ions are generated on the positive half of the line frequency and travel off the electrode as pulses of 60 hertz.
The resistor value determines how many ions are generated. It operates like the principle of electroplating, but in reverse. We are "unplating" the zinc and copper from the brass pipe. Larger values of resistance will reduce the number of ions made. The value can be adjusted by adding a second resistor in series, a method I will show later.
The two main components used. A diode and a resistor.
Mount the diode and resistor on a piece of perf board. The band (cathode) of the diode should be toward the left. The direction sets the polarity.
Bend the leads as shown.
Don't forget to solder the joint between the resistor and the diode.
Cut off the plug end of a line cord. Cut the green ground wire and the white neutral a little shorter that the black (120V hot end).
Strip only the black end and pre-tin the end with solder.
Solder the black lead to the resistor end of the assembly.
Solder to the diode end a length of wire with a quick disconnect female connector.
Check your wiring and cover with two layers of heat shrink tubing. I used "sticky shrink" ( the type with hot melt glue) on the final layer.
The sticky shrink makes a damp proof assembly possible.
The finished Ion Generator
Attach a length of wire to the "electrode" with a pipe clamp. Use a heavy gauge wire because this will errode away in time too.
Attach a male quick disconnect connector to the wire.
The completed Ion Generator, ready to install.
Place the electrode in the water and
plug it to the power outlet inside
the swamp cooler. I modified the outlet so continuous 120 vac is
supplied to the ion generator (bottom outlet), while power for the pump
(top outlet)
is only on when the fan is on. There is a small tab that joins
both top and bottom "hot terminal" of
the outlet made to break off with pliers. By keeping the
ion generator on
all the time keeps the water clean and also allows the electrode to act
as a "impressed
current anode" to save the cooler from corrosion.
Over time, small amounts of the brass will enter the water as ions of copper and zinc and will attack the mold and bacteria.
Over time, small amounts of the brass will enter the water as ions of copper and zinc and will attack the mold and bacteria.
The electrode can be placed near the
intake of the water pump to allow
water to flow though the pipe. Because the bottom of my cooler is
epoxy, the electrode can be placed on the bottom without danger
of shorting out. You may need to place the electrode on a piece
of plastic or other insulating material.
In the photo, you can see "blobs" of something growing in the water, at the pump inlet. This is some type of a bioslime of mold or bacteria that I'm trying to get rid off.
In a few weeks or months I'll check to see if it is still present and see if this device works.
In the photo, you can see "blobs" of something growing in the water, at the pump inlet. This is some type of a bioslime of mold or bacteria that I'm trying to get rid off.
In a few weeks or months I'll check to see if it is still present and see if this device works.
Because current will flow from the
electrode (the copper and zinc ions)
through the water and return back through the ground, be sure the swamp
cooler is properly grounded.
Measured current of .89 milliamps with a meter connected in series with the device. Open circuit voltage is about 60 volts.
WARNING
Use care when handling the device when on. Remember the device is connected to the mains.
Current is limited, but a small shock may be felt if you touch the electrode, especially if it is wet.
This project should only be attemped with those with experience in electronic project building.
TO BE CONTINUED...