Saturday, March 13, 2010

Inventor... or Problem Solver?

I suppose just by the fact that I have invented things makes me an inventor. But that’s not really what I consider myself. I think more of myself as a problem solver. I love to solve technical problems and finding new ways of doing things better. Often that involves a new invention of some sort if there are patentable features.

I don’t know if there is any better feeling in the world than to have just solved some sort of technical problem that has eluded being solved by anyone else.

One of my favorite projects involved sealing conduits. A friend of mine was injection molding some parts for a guy that was selling kits for sealing large diameter conduits, the kind that connect the underground vaults to each other under our streets. His sealing kit was being marketed to a lot of large utility and communications companies like Bell South and Pacific Gas and Electric to replace existing sealing kits which had a few problems.

These underground conduits are made of plastic and after a few big trucks drive over the area they often develop cracks. When it rains the water seeps into the conduits through the cracks and drains into the vaults. The seal is to prevent the vaults from filling up with water.

He had solved a problem and obtained a patent and was now selling around 60,000 kits a month. The problem was his kit did not work, but no one knew that. It was only a matter of time though before someone would test his product and discover it did not really work. His customers routinely tested every few years.

The sealing kits his product was replacing had several deficiencies. These sealing kits used a two-part foam resin to create the seals. The resin was contained in two separate parts of a large syringe, about an inch in diameter and 8 inches long. To activate it you had to use the plunger to break the seal and mix the two resins together. Then you removed the plunger, switching it to the other end of the syringe to inject it into the conduit that needs sealing.

Once injected into the conduit it would rapidly expand forming a foam plug in the conduit and thus sealing it against water intrusion. The main problem was that the reaction between the two resins occurs in just a few seconds, and if you weren’t quick enough in switching the parts around on the syringe it could blow up and cover you with the expanding foam.

Another problem was no matter what size conduit you had to seal you always had to use the whole kit since it gets all used up every time.

The new syringe that the gentleman came up with was a double side by side type of syringe. The two resins would get mixed together as it went through a special mixing nozzle. The nozzle can be detached from the nozzle with a twist and discarded. A cap placed over the opening in the syringe seals the syringes and so you can use some of or all of a syringe depending on the size of the conduit.

Not only could it not blow up, but it saved money by allowing the correct amount of resin to be dispensed depending on the size of the conduit being sealed.

When he first came to me he told me he was having a problem with the mixing. He told me that he needed a better mixing nozzle for the syringe. He explained to me how the better the mixing, the smaller and more uniform the foam bubbles were, and how that produced stronger foam. He didn’t tell me about leaking conduits.

He told me that he was selling about 60,000 nozzles a month and expected to be selling over a hundred thousand nozzles a month by the end of the year. He offered me a nickel a nozzle if I could solve the problem. $3,000 a month? Let’s get started I said.

I asked for some nozzles and syringes of foam to experiment with and he gave me a couple of cases of the kits, and I went to work. The nozzles were long slender tubes with a bayonet type fitting molded into the inlet, and a small hole in the tip of the other end to dispense the foam.

Inside the tube were little turbine like mixing elements. Like little fan blades all stacked up. Each little turbine blade would divide the incoming flow of material into two streams and this was done over and over until the two parts exited the hole in the end of the nozzle.

I went at it using the old trial and error method. I would make some kind of mixing element and insert it into a nozzle and then fill a small plastic cup. After the foam set up I would cut it open and examine the bubble size and uniformity and look for un-mixed resin. I must have tried a hundred different things. I made different kinds of little thing to fill the tube with, made solid elements with a dremel tool and sticks of wood or plastic, and assorted other experiments.

I finally came up with a mixing nozzle that was far better at mixing the materials than what the gentleman was using. When I showed him the foam and he tried one of my nozzles himself he was sold. His top manufacturing guys were there and they were all impressed. And not only did the nozzle mix better, but it would be much less expensive to make than the mixing elements he was currently using. I’ve seen them at my dentist’s office where they use mixing nozzles frequently.

They are commonly used for mixing various types of epoxies and chemical compounds. I’ve seen them in applications from electronics to fender repair compounds for auto body shops.

We never pursued the nozzles, and I’ve never done anything with that idea. Maybe one of these days I’ll go ahead and apply for a patent. I wouldn’t know how to go about marketing it. Back to my story…

The gentelman told me he would test my new invention and let me know how it went. A couple of days later he called me and told me that it still didn’t work. I asked him what didn’t work.

It was only then that he explained to me about the conduits and the sealing against water problem he was having. Remember, he originally asked me to develop a nozzle that mixed the foam better… he did not mention anything about leaking conduits.

We had another meeting where we went over the whole thing this time, including providing me with several of the older kits he was competing against, and a few pieces of conduit for me to using in my testing.

For testing we took 4 foot long 6 inch diameter PVC conduit sections, plugged the end, and stood them up on end after the foam set up. After an hour we would fill the conduit with water and see if it leaked.

The old original kits sealed the conduits but the ones sealed with the syringes always leaked. After each test I would knock the foam plug out with a piece of 2 x 4 wood. I began to notice that the foam plugs that I knocked out were torn up in one spot, but intact an smooth on the rest of the surface that had been in contact with the wall of the conduit. It didn’t take me long after that to figure out that the foam plugs were only “glued” in one spot, the spot where the two part epoxy resin sat after coming out of the nozzle but before foaming up and forming the plug.

The foam plug would adhere strongly to the conduit where the puddle sat before foaming. As the foam rises it forms a skin on its surface and when it reaches the top of the conduit it doesn’t actually “glue” or adhere to the surface.

I took one of the nozzles and plugged the hole in the end. Then I punched holes radially around the tip. Now when the fluid in the syringe is dispensed it squirts out of the nozzle in all directions coating the entire inside diameter of the conduit with the not-yet-foamed resin mixture. It adheres very strongly all the way around. I could not even knock the plugs out with a 2 x 4. Problem solved; not a drop of leakage in any test.

Not long after that the gentleman with the sealing kits went bankrupt for other reasons and I never did see any money. Se la vie!

But one of these days I may get into the nozzle mixing element business. I could make mixing elements that work better than what is out there at about 10 percent of the cost.

Invention Stories and New Product Stories