Friday, April 28, 2017

Cider Press; sizing calculations

I am going to use the cider press discussed yesterday to introduce readers to some of the fundamentals of industrial engineering and Theory of Constraint.

It is inevitable that some step in any given process will become the metronome that paces the output.  Sometime it is a random station (meaning the industrial engineer did not do their job).  Sometimes it is a malingering worker.  Sometimes is due to an incapable process that requires much rework (painting is an example).  Sometimes it is inspection when defects saturate the repair capacity and the amount of "re-inspection" bogs down the system output.

It is desirable to use some intelligence to select the station that will be the bottleneck.  That way the person sizing the components in the system can configure it to "armor" the bottleneck station.  "Armoring" entails doing everything economically possible to protect the bottleneck's run-time and quality-of-output.

In this case, the most expensive piece of equipment is the centrifuge (washing machine) so it makes sense to configure the system to make this the "bottleneck".  The intelligent solution is to do everything possible to ensure that the centrifuges receives "service" at the expense of all the other stations.

Suppose the engineer (you) assumes a 10 minute spin cycle and 5 minutes to unload-reload.    Further, assume that 9 cubic feet will hold 6 bushels (240 pounds) of crushed apples.  That means that  at a minimum the crusher must be able to shred 240 pounds of apples in 10 minutes.  Since the crusher is inexpensive relative to the centrifuge, it makes sense to buy significantly greater "over-speed" to recover from hiccups.

One possible sequence of operations, starting from when the centrifuge finishes its 10 minutes spin cycle is:
  1. Open lid to centrifuge
  2. Hook rope loops of bag with cherry picker, lift and rotate away from centrifuge.
  3. Slide pre-fill hopper over opening of centrifuge (probably need some kind of roller track, it weighs over 240 pounds.
  4. Drop bag out of pre-fill hopper into centrifuge
  5. Close lid
  6. Start centrifuge  (Does that look like less than five minutes to you?  It does to me)
  7. Push pre-fill hopper back into place
  8. Insert the mesh bag.  You will need two because the first one is still hanging on the hook
  9. Start grinder
  10. Dump spent pomace (crushed apples) out of the used bag.
  11. Shake bag.
  12. Rinse bag
  13. Hang bag on hook near grinder for next cycle.
  14. Load six bushels of apples into the hopper feeding the crusher.
  15. Stand next to centrifuge waiting for it to finish its cycle.  This is the "loafing" position.  Physically it saves walk time (which is dead-time) after the centrifuge finishes cycling.  Psychologically it reinforces the idea that the entire process is "serving" the centrifuge.
So how much cider might this set-up produce an hour?

Using three gallons of cider to the bushel, you would expect 18 gallons of cider per cycle (remember, you are processing six bushels a batch).  At fifteen minutes per cycle you should get 4 * 18 gallons per hour or about 70 gallons of cider an hour. 

Just to illustrate the significance of details like the pre-fill hopper:  The person engineering the system might be tempted eliminate the pre-fill hopper and have the operator load the bag into the centrifuge and have the grinder deposit the shredded apples directly into the centrifuge.  The point is that the centrifuge cannot be spinning when the operator is inserting the bag.  The centrifuge cannot be spinning as the grinder fills the centrifuge's drum.  Realistically, eliminating the pre-fill hopper will add another 10 minutes to the 15 minute cycle time and will lower the output to about 45 gallons per hour.

With this kind of capacity, it might make sense to mount it on a trailer with a gas generator and do custom processing. At 24 bushels to the hour, it would take about 15 hours (two work days) to process the apples from a 100 tree orchard, figuring 3 bushels to the tree.  The cider pressing season is about four months long, mid-September to mid-January.  That would be a lot of cider!

Fake News Friday: Waters for President

Fake News Friday: National Endowment for the Arts to fund Bass Fishing

In a move widely seen as an effort to widen their political base, the Democratic National Committee now wants to partially de-fund PBS, dance and fine arts and support bass fishermen, expectoration artists and country music artists.
Darius Rucker, Country Music Artist
"Clearly" Bernie Gravely stated, "there is such a huge amount of support for Sesame Street and some of the PBS news shows that the enterprise could be self-sustaining if they simply dumped shows aimed at the tiniest niches.  And let's face it, 99% of all Classical Music, Ballet and Fine Arts are Euro-Centric.  We need to set an example and be more diverse, more inclusive."

A coalition of the Less Common Genders (Numbers 5-through-58) met at a local Starbucks and wrote a strongly worded memo criticizing the move.  It is estimated that 85% of America's (and yes, that includes Canada) LCG population was able to crowd into the Starbucks and sign the document.

Thursday, April 27, 2017

Cider presses

One of the gentlemen who attends the same church I attend has a commercial orchard.  Not only is it a commercial orchard but a significant portion of their profit comes from certified, organically grown fruit.

I asked Steve if he had any advice for anybody who might wish to follow in his footsteps.  His advice was succinct.  "Get a cider press."

He went on to say that even with the best of culture, organic practices will produce a higher percentage of blemished fruit.  A cider press gives the orchardist a marketing channel for those ugly fruit.

Personally, I am a bit skeptical about the taste and nutrition advantage of "organic" foods.  But I will gladly concede that organic cider is head-and-shoulders above conventional cider.  Conventional cider typically routes the small, green, low-sugar fruit from the shaded regions of the canopy into cider.  It also routes the bruised and damaged fruit.  As the programmers say, Garbage in, garbage out.  The organic cider is made primarily from full sized fruit with balanced sugar/acid and fully developed aromatics.  The fruit's only flaw were unsightly blemishes.

Orchards over 20 acres can purchase turn-key cider mills.  They use a continuous process.  Fruit is poured into a grinder.  The grinder places a continuous pile of ground fruit on a coarsely woven, mesh belt.  The belt carries the ridge of ground fruit between two, closely spaced wheels that look almost exactly like the tires on your lawn tractor.  There is a scraper that cleans the de-juiced pulp off the  belt.  Lather, rinse, repeat.

Those of us who have smaller operations are not as lucky.  The equipment is about as efficient as the printing press Ben Franklin used.

So, I have a modest proposal.  I will suggest certain pieces of equipment as conceptual thought-starters.

Picture a raised platform.  A cylinder, call it a pre-fill hopper, of approximately 20" diameter and 40" of height sits on the platform.  A bag of coarsely woven mesh lines the hopper.  The bag has a line around the rim.  A fruit grinder (like a garbage disposal) is positioned above the hopper.  The goal it to fill the hopper with ground up apple, pears...whatever.  Provisions are made so juice that drains out of the ground up fruit is collected.

Now picture a 9 cubic feet centrifuge capable of spinning 1000 RPM (340gs!!!).  A cherry picker is positioned nearby to pluck the mesh bag of spent fruit grindings out of the centrifuge.  The pre-fill hopper has no bottom.  Sliding it over the centrifuge will cause the bag to drop into it.

Here is an over-priced version of the 9 cubic feet centrifuge.  The reason this centrifuge is over-priced is because it has many features this application does not require.  It is within the bounds of reason that de-contenting this platform so it was only a 1000 RPM centrifuge might reduce the price to $400. 

The pre-fill hopper is required so the grinder can be operating at the same time as the centrifuge.

I once used a garbage disposal to grind fruit and ran into problems with thermal overloads.  Garbage disposals are not designed for continuous operation.  They do not have "cooling".  It would be necessary to find a 1/2 horse power food-grade grinder rated for continuous duty.

Just wishing I could buy a set-up like this, ready made.

Mystery scion wood

This is Prima/M7.  I put four grafts of Enterprise on it.
I was grafting the last two apple trees for this season.  I was top-working a couple of varieties that have not been "paying their rent".

I reached into my bag of scion wood, pulled out a stick and made my cut.

It did not look right.

A normal apple scion has wood that is yellow-green.  This twig was lavender-lilac.

That was perplexing.  There are red flowered crabapples that have purplish wood.  I cannot understand how I ended up with scion wood from crabapples when I thought I was harvesting it from between two rows of Enterprise.
A photo from Feb 14. Enterprise apples.
I collected the wood from a commercial orchard.  It was hard to find wood that was large enough to collect.  I ended up cutting much of my wood from prunings that were lying on the ground.  It is possible that the orchard manager had planted a crabapple as a "pollinator" tree in the row but it seems unlikely.  He did not have large blocks of any one variety which would require dedicated pollinator trees.

I tossed the twig and picked another out of the bag.  It was the correct color.

It makes me wonder, how much of the wood I was grafting was not Enterprise.  I guess I will find out in about three years.  It always pays to collect wood from trees you have personally fruited out and verified as correct.  It pays to look at what you are doing and rogue out anything that looks strange before you invest three years in growing it.  Oh, and be sure to label the bag.

Furnace and A/C are working!!!

Honeywell R8239 "Fan Center"
I think the guy who installed this in the furnace was colorblind.

Signal comes in the bottom and goes out the top to the fan center in the cable on the left.
From left-to-right, white-stayed-white, red-became-yellow, green-stayed-green, yellow-became-blue, red-stayed-red and blue-became-red.  What a nightmare.  It looks like none of the wiring diagrams on the documentation for the fan center.

But rather than straighten out the world, I just mindlessly wired the new unit exactly like the old one.

Except I did not like the short wires between the bus shown in the bottom photo to the fan center.  while it looks tidy it means that fat, old, nearsighted men have to squat on the ground and do all the wiring inside the device.  It is SO much nicer when you can detach the device and hold it in your lap as you switch it over, one wire at a time.

This looks a lot more cluttered but every jumper is now 24" long.  I did not have blue or yellow wire so I wrapped the ends of white wire with the appropriately colored electrical tape.  I coiled up the extra and used twist ties to hold them.  I will use a cable tie to tidy it up even further, but for now I am basking in the glow of success.
Fan works.  A/C works.  Heating function bypasses the fan center and the fan powers up based on a temperature switch in the heat exchanger.  I think we are good-to-go!

The important questions

Suppose you believed in "Spontaneous Generation":  That is the belief that a pile of rags creates mice.  You would be ridiculed as being stupid and anti-science.  Perhaps that "science" was good enough for Aristotle but as Wikipedia puts it  "Spontaneous generation or anomalous generation is an obsolete body of thought..."  But does acting as if you believe an "obsolete body of thought" make you "stupid"?

Consider Thomas Kuhn's proposition in The Structure of Science Revolutions:  Scientific paradigms change when the new paradigm is better at answering "the day's questions of interest."  Since "the questions of interest" are the questions that are least well answered by the existing paradigm, the new paradigm has an advantage.  It does not need to address questions that everybody already knows the answer to.  Those issues are "handled".

Let's get back to Spontaneous Generation.  Public Health officials and wildlife management scientists understand that you must manage the habitat it you hope to control, or manage, the biologicals.  As the father of every daughter knows, babies come from the combination of hot summer nights, cheap pink wine and Pontiacs with capacious back seats.

"Spontaneous Generation" is not obsolete when the questions revolve around managing populations.  In fact, it is the most robust tool available.  You want to eliminate malaria and yellow fever?  Drain the swamps.  You want to get rid of rabbits and woodchucks?  Get rid of brush piles.  You want to stop an epidemic?  Break the transmission cycle.

"Spontaneous Generation", as a theory, leads to more actionable conclusions than mitosis, meiosis, zygotes, halitosis and "ontogeny is the recapitulation of phylogeny."  So contrary to what Wikipedia claims, Spontaneous Generation is not truly obsolete.

We often find that totally abandoning the old paradigm will initiate failures in systems that were considered foundational, systems that were so well understood that they stopped being "interesting".

Sometimes the issue is that decision makers are bored with the old paradigm.  The old paradigm is still considered valid.  It has not been replaced by another, newer paradigm, but by virtue of being "old" is is considered safe to ignore.  An example of this is the high levels of lead seen in many municipal water systems.  The science of controlling pH and phosphate levels has been known for a long, long time.  The guys who used to run those plants had college degrees in science.  The current crop are notable for their political reliability rather than their understanding of chemistry.

Food safety
One of the cornerstones of safe food is cooking.  Cooking kills bacteria, worms, virus, amoeba, paramecium...  It even destroys some of the toxins that spoilage creates.

The Industrial Revolution put a premium on foods that shipped and stored well.  Those foods typically lacked some of the nutrients needed by humans.  In short order, "eat your vegetables" was heard at the kitchen table.  Then the cult of raw/unpeeled food arose to ensure that the maximum amount of nutrition made it to human stomachs.  This was enabled by the science of the Industrial Revolution, sanitary sewage handling, refrigeration and "chemical" fertilizers.

The pendulum swings.

The world is more crowded.  As the population grows, larger and larger percentages of the gross planetary product goes directly to humans and our surrogates.  Pathogens that used to smolder and then extinguish for lack of suitable hosts now thrive because of the short hop from host-to-host.

A fine example of this is the Rat Lungworm.  According to this article in The Atlantic, RLW is now endemic to the southeastern United States and is relentlessly marching north and west.  RLW is transmitted by the invisible snail-trails found on lettuce, kale, tomatoes...heck, everything that snails and slugs might crawl across.

So the food safety paradigm that used to mandate cooking food, swung to eating raw, unpeeled food and is now likely to swing back to cooking food.

Will be discussed another day as this post is already a bit too long.