Inventors Notes – Switching Electronic Air Pressure Regulation

My Asparagus harvester invention utilizes pneumatic cylinders to cut the individual spears, and the stroke length has to right on the money every time. If the pressure goes up the stroke length becomes longer, and if the pressure goes down the stroke length shortens.

Too much pressure and the piston rod will bottom out against the front cylinder head, and not enough pressure will reduce the stroke length an cause the blade to not cut all the way through the spear or even not reaching the spear at all. Allowing the piston to bottom out against the front head will eventually damage the cylinder.

The asparagus harvester has 14 air cylinders mounted on the header arranged across the asparagus bed. Each piston rod is equipped with a sharp blade with a slight bit of overlap with the blades next to it. The cylinders are angled down toward the ground and when they extend the blade severs the spear slightly below ground level requiring a stroke length of about 20 inches. Typically the extension stroke takes around 35 to 40 milliseconds.

An optical detection system locates the spears and sends a signal to open the air valve for the cylinder corresponding to the co-ordinates of the spear to be cut. The harvester is moving forward at between 20 and 30 inches per second, and so the blades must cut the spear and get back up out of the way of any spears that are not quite tall enough to harvest.

Asparagus spears emerge from the bed in a random pattern with random heights. At any moment during harvesting there may be as many as 5 or 6 cylinders operating at the same time, or none at all. You might have 10 feet with nary a spear, and 18 spears in the next 24 inches.

Because these cylinders are very fast acting they require high flow rates at a constant stable air pressure. While stroking, the cylinder will be consuming around 165 cubic feet per minute of air. Six cylinders operating at once would require a whopping 990 cubic feet per minute.

With such large swings in flow and rapidly varying air consumption the mechanical air regulator will have a significant variation in the pressure drop, which will have a detrimental affect on the stroke length of the cylinders.

We can, however, use another approach to regulating the air pressure. We can use a switching electronic air pressure regulation scheme. With this approach we replace the mechanical pressure regulator with an on or off electric air valve with a high flow rate.

We can then use an accurate analog pressure transducer to open the valve whenever the pressure drops below the set point, and shut off when the pressure is at or above the set point.

The valve has a very low pressure drop unlike the mechanical regulator. The valve can handle the flow required by multiple cylinders without the air pressure drooping that the mechanical regulators end up with.

There will be small pressure spikes or what is known in electronics as a ripple in the pressure. By properly sizing the manifold I can filter out the small pressure ripples.

For more details about electronic switching air pressure regluation for the asparagus harvester

Future Million Dollar Inventions and Ideas

Want to invent that million dollar invention or idea and be set for life? It’s not terribly likely that you can do such a thing, but it’s not out of the question either.

History is full of individuals who achieved great wealth with a new invention or a new idea. Ray Crock who franchised Mc Donald’s, Steve Jobs and Apple computer, Bill Gates and his operating system, snugglies, spanks, and someone is even making a fortune because he came up with the idea of slip on cardboard coffee cup holders so you don’t burn your fingers while holding that paper cup latte.

Here are the areas where I think the small individual inventor or innovator has the best chance of coming up with that revolutionary device or idea that will make him or her independently wealthy.

Harvesting Machines for Fruits and Vegetables

Very few fruits and vegetables are harvested by machine. There are tomato harvesters and potato harvesters but not much else for fruits and vegetables. If someone can com up with a harvester for apples or oranges or similar fruit the will make a huge killing. It will truly be a million dollar invention.

Other crops that are exclusively hand harvested are asparagus, all kinds of citrus, squash, brussel sprouts, cauliflower, and man others. I’ve almost got an asparagus harvester working, you can see my latest version at my asparagus harvester website.

Energy Production

Obviously energy is always going to be needed and with oil eventually running out there are many new competing technologies for generating electricity. Opportunities abound with areas such as wind power, ocean wave power, solar cells, biofuels, and more. Figure out a way to generate electricity that costs less than generating electricity with oil or gas and you have a winner.

A Better Razor

Just image how much money you can make selling razors. Nearly every man and woman in the US and many other parts of the world shaves. How about a new kind of razor that you could use to get a comfortable and close shave with just plain water? Even better would be a razor like the above that needs a new blade every week. You could have millions and millions of customers purchasing replacement blades weekly or monthly.

The Internet

First there was America Online, soon there was ebay, craigs list, facebook, twitter, and god knows how many other social networking and other online methods of making money. All of the previous mentioned items started out as an idea. You can have ideas too. Come up with a great online game that everyone wants to play. My wife is currently addicted to a farming game on facebook I think. Find some new way of helping the masses communicate with each other is another idea, and one will probably emerge this year in my opinion. Flex your creativity and come up with the next big thing on the internet.

Geriatric Products

Anything that helps older people get along as they grow old should be big. Soon the baby boomers will all be old, so find a way to make life easier for them. This could involve the internet and some sort of social media thing too. Interesting areas for new devices include things that make bathing easier, taking medications and keeping track of medications, exercise equipment, sleeping aids, and all sorts of other convenience items.

Cooking and Food Preparation

Everybody eats and they eat every day. Come up with some food preparation or cooking device that makes preparing or cooking food easier and then sell it on those infomercials. There is a lot of money in it, just come up with something simple and clever that makes a kitchen chore easier or quicker.

Water and Energy Conservation

As previously mentioned, energy is big. Find a good inexpensive method of saving energy. Saving water is just as important and will only get more important. Find a new way to desalinate water, or purify water, or a way to save large amounts of water.

These are just a few suggestions, there are countless others awaiting your discovery. Go forth and Invent and Innovate! Be the next one to come up with that million dollar invention or idea!

Outsourcing To China – Problems Crop Up Continued…

We outsourced our pump manufacturing to China, due to our inability to find a manufacture in the US that could provide us the pumps at a price we could make a profit with. It’s not such an easy process. Good communications are critical, and so if you have to deal with a very small Chinese manufacturer you need a good go-between person who is fluent in both English and Chinese.

We were having a problem with a seal, well not us, the Chinese manufacturer. We were life testing the seals for the pump, as was the manufacturer. His seals consistently failed after a short time. Using the same parts and test procedures, (we thought), our tests were working out just fine.

I finally after weeks of going back and forth trying to find out the details I asked him to send me one of the “failed” seals.

It turns out that the manufacturer meant “leaked” when he said the seal “failed”. We wasted over a month trying to figure out what was making the seal fail before we found out it wasn’t a seal failure after all. It was another part that was failing and causing the leak, not the seal. It turned out they were testing with a slightly higher pressure than we were, which caused a plastic part to fail.

Good translation is obviously important when you are dealing with a manufacturer on the other side of the globe.

Injection Mold Tooling Problems

We have found the tooling for our plastic injection molded parts are somewhat sloppy. The parting lines are all obvious and slightly out of place, the ejector pins don’t all land on the surface they are intended to, everything is done kind of half-assed if you ask me.

Keep in mind, this was a very low budget, and with our limited funds we didn’t really have a lot of choices. The tooling works and produces parts that work, but they aren’t very pretty.

Getting code approvals in China

Working with ETL testing labs in China was just as difficult. I had to argue constantly with the Chinese engineers who worked at the ETL facility in China. Thank god for the Internet! I always won the arguments, but it took a lot of work researching and supplying documentation to the Chinese engineers.

I remember one disturbing argument; the Chinese engineer was telling me the fuse I was using for the motor was too small and needed to be bigger.

What? Bigger? How is a bigger fuse safer? It was a very surreal experience. Fuses take time to burn out. If a fuse is rated for 2.5 amps, and you run 2.6 amps through it, it may take several hours to blow. If you run 3 amps through it, it may take 30 minutes to blow. If you run 10 amps through it, it will blow in a second or two etc.

Our fuse was to protect against “locked rotor” conditions in the motor. Locked rotor is where the motor shaft is held and not allowed to rotate. Our locked rotor current would blow the fuse we were using in about 2 seconds, well before anything got hot enough to cause a fire. The fuse they were specifying would have taken several minutes to blow and danger of fire would be very real.

They finally relented and allowed us to use a fuse smaller than what they wanted but still larger than we would have liked. The one we use blows in less than 10 seconds at locked rotor conditions, but I would rather it blow in less than a second.

I’ll have more Chinese outsourcing stories in the future… some good, some bad, and some just plain funny.

More about our outsourcing experience

Manufacturing Our Product in China – Unusual and Odd Problems Crop Up

We manufacture a pump in China. The reason we have it done in China is to provide an actual profit margin. We started manufacturing it in the US, but it reached the point where it just cost too much, it was either fold up the company or outsource to China.

We opted for outsourcing the pumps to China.

We’ve been having the strangest problem concerning the lip seal we use to seal our pump motor shaft. It is a standard 1/8 inch cross section x ¼ inch ID x ½ inch OD lip seal. After we started manufacturing the pumps in china we began having substantially more warranty returns due to leaky pumps.

It took a long time, but we finally realized that occasionally the seal would spin inside the plastic gland it is contained within. It turned out that for 10 years we had been using the wrong cross-section type of seal, which was symmetrical. Now the factory is telling us we shouldn’t use that type of seal for a rotary shaft application. It would have been nice if they had mentioned it 10 years ago when they helped us choose a seal.

And it worked so well for 10 years! Thinking back on it, we now know why we had some mysterious leaks even back then. There were a whole host of changes we made when we switched to the Chinese manufacturing, but we still used the same motor shaft sealing technique and seal.

To solve the spinning problem the Chinese manufacturer had some custom seals molded, but when he did the life-testing, the seals were only lasting from a couple of minutes to an hour or so. Wee need a 500 hour life or better.

We spent weeks trying to figure out why the seals only seemed to last for a few minutes to a few hours when the Chinese manufacturer did life testing on them. Our life testing of the US seals we had been using was getting life expectancies of about 500 hours, unless they spun of course.

We could not figure out why the Chinese tests were so poor… let’s say catastrophic, Same motor and pump, same stainless steel shaft, same plastic pump housing, same water pressure and temperature. We decided it had to be the material the Chinese were using.

We found a compounder here in the US who would custom make us the rubber material, Nitrile, with the properties we needed for our pump. The minimum order cost us about $1,000 but we got enough material to make about 80,000 pumps. The seals are pretty small after all.

It took about a month to get the compounder to furnish us the batch of nitrile and we shipped a small portion off to China for them to mold into lip seals.

Again the Chinese life testing resulted in seals only lasting minutes. We investigated the curing times and molding method the Chinese factory was using and tried changing those parameters. Same result.

I was getting quite frustrated. The Chinese were blaming “abrasion” for the problem. I told them to send me some samples of the new seal including one of the “failed” seals. When the seals arrived and I found the “failed” seal I was a bit puzzled. I could not tell the difference between the new seals and the failed seal. It looked brand new.

I installed the failed seal in a new pump and began life testing the pump. After about 200 hours of running I took the pump apart and checked the seal. It showed significant wear as would be expected, but inner lip still had more than half the original thickness. There were no leaks.

To be continued…

Inventing an Asparagus Harvester – 30 Years of Prototypes

I first decided to invent a selective asparagus harvester in about 1972. I asked my dad one day if he knew of something that needed inventing… I was bored. He was a farmer and an asparagus grower. He told me they needed a mechanical asparagus harvester that would just harvest the ripe spears; a selective asparagus harvester.

Not knowing any better I decided I would build one. At the time I was about 21 years old, fresh out of the army, and pretty good with electronics. I had a ham radio license when I was about 13 years old, built my own transmitters and receivers, and could fix anything from a car radio to a color TV.

I had read about a new kind of imaging device, I think it was one of the first CCD chips. I don’t remember all of the details, but the camera had basically 16 rows and 16 columns of light sensitive elements, and I decided to use that to detect the height and location of the spears on the bed, and I would use blades attached to air cylinders aimed toward the ground at about a 45 degree angle. I used eight cylinders arranged in a row across the bed, and when the camera spotted a spear tall enough to cut, it would activate the valve and fire the air cylinder that was lined up with the same column as the spear.

A friend of mine and I built a little demonstration prototype that had a little gas powered air compressor built out of channel and angle iron and 4 motorcycle tires that we pushed by hand. It had the camera, air compressor, 4 cutting cylinders and a crude pickup device that would grip the spears as they were cut.

That first prototype was enough to interest a local machine shop that decided to take risk of developing a selective asparagus harvester. They hired me for $2000 a month to oversee the development and took a 50 percent share of the rights to the machine. We spent the next ten years working on it, coming up with a new prototype each year.

The camera turned out to be unsuitable for the task, and during those years I tried just about everything you could think of to detect those stubborn spears of asparagus. I tried little wire bales that hung down from above, beam-breaking photo electric sensors, retro-reflective optical sensors, magnetic switches with plastic paddles, and even a Reticon line scan CCD camera, but all had serious drawbacks.

I really wanted to try a laser for illuminating the spears due to the precise position information I could get by using a laser shooting across the bed. It would be able to give me much more accurate information about where the spear was located on the bed and it’s height. But at the time lasers were several thousand dollars, and not nearly rugged enough to mount on an asparagus harvester.

Asparagus spears can be very delicate, and on cold mornings it is very easy to break a spear by just nudging it a bit. So you really don’t want to use something that has to contact the spear to detect it. Using through-beam sensors required mounting the emitter and receiver at the height of the spear you wanted to harvest. If you wanted to cut nine inch spears you mounted the beams nine inches above the bed. Harvestable spears would range from nine inches to about 16 inches on hot days. The longer spears fortunately are harder to break.

We used extremely thin sensors to avoid touching the spears, but you could still see the occasional spear break as it made contact with the sensor itself.
Another problem with sensing the spears was the fact that asparagus spears can lean in any direction, and significantly throw off the targeting of the spear. At the point where the spear reaches the nine inches off of the bed, it can be several inches to one side or to the front or back of where the spear actually emerges from the ground. That makes it a whole lot harder to cut the spear. Especially if the blades are narrow.

In 1984 we gave up the project due to lack of interest on the part of the asparagus growers. The machine was a self-propelled 3 row selective asparagus harvester. It wasn’t perfect yet but it did harvest asparagus.

At that time we used beam-breaking for sensing the spears; I think they were 4-1/2 inch wide channels the spears had to pass through.

The sensing of the spears and locating them were not the only problems we had in developing a selective asparagus harvester.

My next blog entry will discuss the difficulties we had with the air cylinders. And some of the inventive ways we found to address the problems… and why most of them did not work.

The Old Inventor Guy

A New Patent - How to get a Patent or Patent Protection

Getting a patent for a new hot water system

I filed for a new patent a few days ago. The patent is for an improved hot water delivery system for residential and commercial buildings.

The new hot water delivery system is capable of providing faster than normal hot water delivery to any fixture in a home or building, and only to that fixture where the hot water is needed.

The basic idea is to place a pump at the water heater which when running will create a pressure difference between the hot and cold water lines with the hot water lines having the larger pressure.

At each fixture a cross-over valve connects the hot and cold water lines. The valve has a controller which has a temperature sensor in contact with the water in the valve. Each valve controller also has a communications link with the pump.

When you want hot water at any particular fixture you activate the valve by pressing a button that is either hard wired to the valve or uses a radio frequency transmitter to activate the valve. The valves can get their power from either the house current or batteries. Batteries would be great for retro-fit installations. We estimate the battery life to be a minimum of two years using four AA cells per valve.

When you press the button activating the valve, it checks the temperature of the water at the fixture, and if the water is not already hot, the valve controller sends a signal to the pump to begin pumping. The valve controller also at the same time opens the valve between the hot and cold water lines. Thus hot water begins flowing from the water heater with the cooled off hot water in the hot water piping being sent back towards the water heater through the cold water line which hooks to the inlet of the water heater somewhere.

So basically that is the new invention. Let’s examine the steps I’ve taken for protection so far. In a future blog I will cover how the patent attorney and I worked out the details of the patent, especially the patent claims.

After my partner and I decided we had a good idea for a new product we knew we needed to get patent protection. My partner found a patent attorney through a relative, a lawyer working for a very large and expensive firm. But what the heck, hopefully we would be able to obtain a good solid patent that could be enforced in the market place.

Foreign patent protection is complex and expensive. Very expensive. We decided to stick to just he US and Canada. Canada adds about $1,500 to the cost of filing.

I don’ remember all of the costs at this point, I did not sign the checks, the company did. I will be looking them up and reporting on all the details as far as expenditures go in the near future.

Our patent lawyer explained to us that the least expensive way to get some form of patent protection on our new idea was to do what she called a “document dump”. We gave her documents that explained the invention in detail, and she did the “document dump” which serves as proof in a court of law of when we first thought of the idea. Of course we could have thought of it 10 years before that, but this is absolute proof that you had thought of if by at least the day of the dump.

The reason we went with that was we had no money to pursue a patent, and this was the least expensive way to obtain some protection.

More about patenting the new hot water system in a future blog.

Bill the old inventor guy.

First Invention Blog - Testing the Waters

Ok all you wantabe inventors, I'm starting this blog to help you out. I have been inventing my whole life, beginning in the early 70s. I have over a dozen patents and I just filed for another patents a few days ago.

In this blog I plan to discuss all kinds of things relating to inventions. I'll relate things I've learned over the years, and new insights when I get them. Many of my patents are related to water heaters and hot water circulating systems with some other gadgets and gizmos thrown in.

Online marketing is another subject I will be delving into. I've done pretty well with SEO for some of my web sites, and we are selling one of my inventons online successfully.

One of my inventions is being made in China, and that will also provide fertile ground for blog posts. Lot's of nifty headache stories... LOL

I'll begin all of this with my next blog. For the time being I need to go finish setting up all the details for this new blog. Ugh!