What’s All This Hydraulic Ram Stuff, Anyhow?

March 23, 2011
Bob Pease remembers a "hydraulic ram" he saw in a Sears catalog when he was a kid, prompting some thoughts about oscillation, switching regulators, and taxes.

When I was a kid, I was impressed with a lot of things you could buy from the Sears & Roebuck catalog. One was a “Hydraulic Ram.” If you had a small stream on your land, you could buy a hydraulic ram to take in a lot of low-pressure water and pump a little of the water to a higher level, such as up to your house.

It wasn’t very efficient. It was LITERALLY clunky. The water would flow past a small chamber, building up inertia and momentum. Then a clack-valve would close, converting the momentum to pressure. The pressure would cause a small amount of water to squirt up with enough pressure to get the water up to where you needed it.

The oscillator was obviously “self-starting.” This is one of the first places where we could be exposed to a “switch-mode converter.” It worked that way back in 1940, and surely for 60 or 80 years before that. It was not a “switching regulator,” as no regulation was involved. But it was a kind of magic! Enough to get a nascent engineer thinking. Isn’t it funny that a current flowing in your stream has the same name as the current in a wire or inductor? With various analogous properties.

Around The House

Back in 1957, I was shovelling a little snow, about 3 inches of wet snow from a sidewalk. I would scoop up a medium shovel-full and throw it over a small hedge. But if I did not quite get the snow above the hedge, some of the snow would hit the edge of the hedge and push it over a couple inches.

As most of the snow fell away, the hedge would spring back and throw a small amount of snow back onto the clean sidewalk. Maybe just a tablespoon or two, but enough to notice! I had to go back and clean up these dribs and drabs of snow. I remember this clearly.

Recently, my wife began complaining that I was leaving our range-top kind of messy. How so? When I make coffee, I get the coffee cup half full of coffee and then pour in about an eighth of a cup of cream (half-and-half) from a pint carton.

When the cream hits the coffee, it disturbs the surface of the coffee, which then throws one little drop of cream up and out and over the edge of the cup and onto the stovetop. This is a lift of a full 1.5 inches. It’s another example of a switcher—very informal, but not made by human hands. I’ve even watched as a small stream of milk caused a drop of the milk to leap 3 inches above a half-full cup of tea, over the edge of the cup, and onto the stovetop.

Does water make a splash like the cream does? Milk? Heavy cream? I haven’t run any tests yet, but yeah, the cream does tend to splash up more than water does.

My father had a 1941 Ford sedan, and it had a radio. I did not know it, but the “whine” we heard from the radio was a vibrator making a switching converter, taking in a lot of power at 6 V and putting out a few milliamps at 90 V to run the plates of the radio tubes. At that time, I was not repairing or taking apart car radios, but I bet some of you guys were. Comments?

More Fluid Dynamics

The ability to store energy in a slow flow of water can lead to a crude pump that can raise water above “ground level.” The hydraulic engineers back in the 1870s were pretty ingenious!

The money from gold mining made a lot of experiments and engineering possible. The ability to store energy in an inductor, and suddenly “break” or “switch” that path, led to the whole switching regulator industry we see today. Step-up and step-down.

What does this mean to those of us who do not use “switchers”? The other day, I had to pour some water into my car battery. Watching closely, I saw that as the water blooped into the battery, a tiny drop of liquid came out.

I didn’t have any pH strips, but I bet it was pretty strong acid, not just water. To avoid holes in my shirt, I’d better stay away from these little drops! Comments?

Dirty Dealing? By my Rich and Wise Uncle Sam?

Recently I got a refund check on my state taxes. When my wife asked, “Do we have to pay taxes on this income?” I replied, “Oh, yes...”

Then I realized that when I earned the money, I had to pay federal and state income taxes on it, and the state taxes may not be exempt from federal tax. So I have to pay tax on the taxes. Then, because my income was so hard to estimate, I overpaid my state taxes—and I have to pay more tax on the tax on the tax.

Tax experts tell you that if you overpay your taxes, it’s no big deal. You just have to wait until you get your refund. But nobody (except rap) is telling you that you may also have to pay taxes on top of the taxes. And even on top of the refund.

So it is worth some effort to pay up near your tax due and not overpay it, because your refund may get screwed. The last time I looked, the IRS tax rate was up near 43%, and at that rate, double taxation is painful!

So, do as I say, not as I did.

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