Defeating the Flushmaster patent: automatic toilet bowl cleaner

You really never have to brush the toilet bowl again for less than $1.  You only need to open the toilet tank maybe once every 6 month and drop some super cheap household chemicals in it.

My previous improved version of the Flushmaster split the water from the fill tube into 2 paths, but still using the Flushmaster.  It was a temporary fix for prove of concept.  Once the concept is proven, using the Flushmaster is totally unnecessary, overly complicated, inconvenient, and unreliable.

Since my new design is patentable, I look up the patents reluctantly.  Reluctantly because there's not much money to be made because everybody can build it for less than $1.  But still, many people will still want to just buy and drop one in the tank and forget about it.  Fortunately, Flushmaster has already patented the concepts in 2007, so I can disclose my findings immediately and not spend my time in the toilet business.

The current Flushmaster gadget is patented about 2001.  Why they don't give you products with the new 2007 patent? Money!  Now the refill cartridge sells for $7 (?) and last for about a month for a large family with older high flow toilets.  That's totally not bad if you don't have a cleaner/house keeper.  That's a steady revenue stream that the new produce will decimate.  And if you see the new thing, probably you want to copy it for less than $1.

Overflow tubes are 1" pipes slightly narrower than standard PVC 1" pipes.  So the whole thing is based on 1" pipes and fittings.  In this final assembly, the Tee on the right just slides onto the overflow tube.  Nothing is needed to modify permanently any existing fittings.

For this design, the chamber on the left stands on the tank bottom.  This is not necessary.  To secure the assembly in place all you need to do is to glue a 1" coupler to the Tee on right.  That will hold anything securely in place using the overflow tube itself.

The whole assembly need to be water tight so the chemicals don't leak a lot into the tank.   Since the assembly is not under any pressure, you can just use PVC glue to put them together without worries.

Water from the fill tube is split into two branches.  The main branch goes into the top of the Tee on right, via a 1/4" hole, drilled with a plastic drill tip so it doesn't slip during drilling.

The 2nd branch fills the chemical chamber, via a dripper or flow restricter or narrower tube or you don't even need a 1st branch.  When the chamber overflows, the cleaning solution goes into the flow tube.

Since the overflow tube and the 1" Tee is only loose fit, I put some plumber's pudding on the edge of the flow tube to seal, so chemicals can't leak into the tank.  I don't think you need it because instead of NOT allowing drop-in-tank cleaner manufacturers to destroy flippers and gaskets, the new standard seems to require everything in the tank to withstand cleaner chemicals.  I spend time for this new design because chlorine destroys drippers for gardening drip irrigation.  It only lasted for a couple of months though it is dirt cheap.

If your fill valve ever malfunctions, water goes into the overflow tube horizontally via the Tee on right.  The "critical fill level" changed a little but you can adjust it.  I think this is or can be plumbing code compliance.  A simpler gadget will be based on 3/4" pipes and fittings.  A 3/4" tube goes nicely and tightly into the overflow tube.  There is no possibility of leaks.  But the effective overflow tube size is reduced to 3/4".

1" chlorine tablets simply drops into the chamber.  But I am experimenting with something better.  Let's see this in the tank. (The old Flushmaster is there totally unused.)

Recap: standard 1/4" pipes, for fridge icemaker or gardening drip irrigation goes straight into the white fill tube.  Pick the slighter tougher ones and you can insert it far into the fill tube, forming a water tight joint.  You also need a 1/4" tee and a dripper.  I'm experimenting with the flow rate but currently I have a 2 GPH dripper.

I have an older version that uses 1" chlorine tablets.

To reduce the swimming pool smell, you can make the tank lid reasonably air tight, or you can use a standard 1" plug to cover the Tee at the chamber opening.  The dripper is inside the plug so it will not hinder the chlorine tablets when taken out with the plug.  I rotated the chamber so it is lower profile to fit into the tank with the plug half in.

Chlorine tablets can go through standard 1" pipes, tees and caps, but NOT plugs.  So you have to allow enough space if you use plugs instead of caps.

I do not recommend expensive 1/4 tee's.  It's easy to take the tubes out but only when not inside the tank for months.  Drip irrigation tee's are much cheaper.  If you ever need to disconnect the tubes, cut the tubes, discard the tee and the tubes.

To really reduce the chlorine smell, like any drain you can add a u-trap at the open tee.  It's clumsy for 1" fittings but there's should be enough space for that.  The u-trap should be refilled with fresh water every flush.  The top level of the u-trap should be slight higher than the overflow tube so water will go into it rather than the tank.

Again, there's nothing wrong with the Flushmaster, but you can be environmentally friendlier.  First, they use a lot more chemical than required.  Their new patent sort of admitting that, or, you do not need to buy expensive slow dissolving tablets to avoid refilling too often.  They design the rubber seal so flimsy that you cannot refill it yourself with chlorine tablets. You can at most reuse the o-ring a few times.  I have yet to find o-ring in hardware store to fit without using pliers to twist the cartridge out.  My design works at low pressure and you don't need any seals.

As for the new chemical, I can hint that it is very cheap and easy to find.  If your tank is larger you can fit in a few chambers and you might not need to refill in a year's time.  I have calculated the solubility of chemicals and nothing seem to last a week  unless you make some large crystals so they dissolve much slower.  But this is barking the wrong tree totally.  You'll see.