Re: Another water pump automation project (suggestions ?)
Hall Effect switches have been used in crank shaft position sensors for years. Many millions and millions of cars and trucks have them. Although there may be a problem in very few vehicles, I would say their success rate is around 99% for several years. Unlike your pump a crank shaft sensor has to turn on and off several times a minute. These sensors can work in dirty environments successfully. I would say there has to be many ways to successfully enclose a natural magnet in a float so as not to compromise it.
The tank you talk about replacing tells me whomever designed the float and the magnet inside most likely needs to go back to design school because components fail and tank lids need to be taken off if only for cleaning the tank inside, tanks get dirty. I sure would not use a reed switch and magnet to close it on the outside of the tank. One job i had while I was attending College was as a Security Alarm installer. The magnet and reed switch are used in that industry. They fail quite a bit of the time. You need to look up Hall effect switches. They will acquire a small amount of current from the magnet when it comes in line with it. I would say that the hall effect switch would be places at the top of the water line where water pressure is not great. It actually could be places above the water line. The top of the float in the tank could also be place above the water line. So even when the float went down it would still be above the water line. One could actually place the Hall effect switch inside the water tank in this case. Depending on plastic of the tank one could both screw into the tank and also have a plastic adhesive on the mounding bracket for the Hall Effect switch The Hall Effect switch then could be mounted with stainless steel screw and nut on to the bracket so it could be removed easily. Of course, one has to have a removable Lid on the tank to do this. On then could drill a hole in the lid so the wires to the hall effect switch can exist. The wires would be sealed with food grade silicone caulk where they exist the tank. If the tank does not have a lid one could make a lid for it. Simply mark a circle around the tank near the top on the side of the tank. Use a plunge cutting tool and follow around the marked circle. Then buy food grade gasket maker. Line the cut top with this gasket maker. Then put the top lid on after the appropriate time and wait for a little more time then secure the top lid with stainless steel screws.
If cutting the whole top off is too much, then just cut a section off big enough for a human to get in the tank and clean it. Use stainless steel hinges to secure it to the top and a side hinge. use the gasket maker to fill the space where cut and then tape over the gasket maker.
Of course, some big manufacturers who want to cut cost like Ford Motor Company will design something that is almost impossible to replace without pulling the engine. I believe a friend of mine had a 7.3L Diesel sensor that went bad, and it cost over $700 to replace it. Luckily the truck was still under warranty.
Originally posted by Dannyx
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The tank you talk about replacing tells me whomever designed the float and the magnet inside most likely needs to go back to design school because components fail and tank lids need to be taken off if only for cleaning the tank inside, tanks get dirty. I sure would not use a reed switch and magnet to close it on the outside of the tank. One job i had while I was attending College was as a Security Alarm installer. The magnet and reed switch are used in that industry. They fail quite a bit of the time. You need to look up Hall effect switches. They will acquire a small amount of current from the magnet when it comes in line with it. I would say that the hall effect switch would be places at the top of the water line where water pressure is not great. It actually could be places above the water line. The top of the float in the tank could also be place above the water line. So even when the float went down it would still be above the water line. One could actually place the Hall effect switch inside the water tank in this case. Depending on plastic of the tank one could both screw into the tank and also have a plastic adhesive on the mounding bracket for the Hall Effect switch The Hall Effect switch then could be mounted with stainless steel screw and nut on to the bracket so it could be removed easily. Of course, one has to have a removable Lid on the tank to do this. On then could drill a hole in the lid so the wires to the hall effect switch can exist. The wires would be sealed with food grade silicone caulk where they exist the tank. If the tank does not have a lid one could make a lid for it. Simply mark a circle around the tank near the top on the side of the tank. Use a plunge cutting tool and follow around the marked circle. Then buy food grade gasket maker. Line the cut top with this gasket maker. Then put the top lid on after the appropriate time and wait for a little more time then secure the top lid with stainless steel screws.
If cutting the whole top off is too much, then just cut a section off big enough for a human to get in the tank and clean it. Use stainless steel hinges to secure it to the top and a side hinge. use the gasket maker to fill the space where cut and then tape over the gasket maker.
Of course, some big manufacturers who want to cut cost like Ford Motor Company will design something that is almost impossible to replace without pulling the engine. I believe a friend of mine had a 7.3L Diesel sensor that went bad, and it cost over $700 to replace it. Luckily the truck was still under warranty.
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