Ironmongery

I wish the picture upload was faster; I could then post a photo of my latest struggle. It takes the form of an oil expeller made in (I think) northeast China that weighs about a ton-and-a-half and is one of the more amazing pieces of cast iron I've yet seen.

Brief aside: For those of you who don't know, one of my favorite hobbies back home is refurbishing / reseasoning / rescuing  cast iron pans and giving them to friends. If you've never cooked with cast iron, you've neither eaten or cooked. And if you're using one of those chintzy pans from Wal-Merde, you'll be intimately familiar with the quality of cast with which I'm working.

Anyrow, Thursday, a guy from Mongu who is the expert in wiring the motors and operation of expellers came down to help us wire up the starter motors (essentially a mini-transformer box that does some step-down on the three-phase power line fitted with a "start" and "stop" button). I shoveled a meter-deep trench between the warehouse (where the distribution box is) to the oil shed. Did it myself because we had a cold rain all morning (weird for this time of the year) and the trustee remain huddled on the veranda of the warehouse, warning me against working in the rain.

Brief aside #2: Zambians loathe cold. People start dressing up like its December in Ottawa this time of year; jackets and hoodies (secondhand saluala from the States) and a multitude of gloves / mittens are the rule. People hurry wherever they are going and respond to greetings, not with the usual "I've woken well, and you?", with "Cold!" and hustle along. As far as I can tell, most folks figure you'll catch the flu from cold weather. Now, mix in rain, which is still thought by many to cause malaria if you're exposed to it, and you have a situation in which people won't leave the house. As such, Senanga looked deserted Thursday morning.

Anyway, Mr. Likando wired up the boxes. It took most of the day as we kept having to send our trustee, Mr. Simasiko, into town for supplies (our production site is about a mile and a half from the market). We got the oil mill wired up by 19:30 and fired it up at 19:38 (7:38p). By God and all that's holy, in the pale glow of the fluorescent lights, it turned on and started whirring away. I almost broke taboo to hug Mr. Likando; as it was, I just about shook his hand off his shoulder.

The next day, he offered to stick around and show me how to run the mill as his project had some off-days (he supervises a jatropha-to-diesel fuel project that is struggling along in Mongu). So, starting around 7:30, we started the engine up and slowly fed sunflower into the hopper; you do this for 20~30 minutes to slowly build up the heat in the helical screw. It also gives you the time to do adjustments to the screw and tighten or loosen the rings. The former controls the overall moisture of the cake; you want "dry" cake, i.e., all the oil is squeezed out of it; once you get this, you are pressing well. Otherwise, you have to recycle the wet cake back into the feed hopper mixed in with fresh seeds.

It didn't take long for us to break down as a result of a simple mistake. The engine has three belts that run to a large pulley that rotates the helical screw. However, one pulley is run off of those to a small driveshaft that runs across the top of the machine and turns an agitator in the hopper that stirs the seed and augers it down into the screw. The pulley wheel hadn't been screwed in correctly, so it started turning freely on the driveshaft and the agitator/intake auger consequently stopped. We shut down the engine, disabled the belt, and reset the wheel; however, by the time we got it fixed, the cake had hardened inside the rings and frozen the helical screw in place. As Papa Bear Likando said ruefully, "This is why we don't stop the engine."

It's a 60-80 minute job to break the screw loose; you have to knock all the rings loose with a hammer and chisel, then chisel the cake of the outside of the cake, which has a consistency not unlike a frozen hockey puck. After that's all done, you reset the rings, check the screw and start up again.

The second round went far better; we got the adjustments right, and the machine started to really heat up due to the friction. According to Pappa Bear, this was a good thing, as you drive more oil out of the seeds once it gets good and hot. I mean really hot; we could literally fry eggs on the shield, and you could hear the seeds popping inside the rings. The oil was consequently heated, and our shields aren't adequate enough, so I kept getting hit with burning oil the rest of the day as I shoveled cake away from the outlet. I didn't mind at all; Pappa Bear kept up a running commentary, and by God, I was learning. It's not often enough that I'm getting formally taught by a Zambian (by default, people assume/expect you to have more knowledge / be the teacher / etc.) and he was a fount of knowledge. Also, I spend most of my time running around trying to get things working, and very little time actually seeing them work.

PB and I went back to town, and I bought him lunch before he headed back home to Mongu. We pressed a grand total of twenty liters from about 60kgs of seed; much of it's quite sludgy (unfiltered or unclarified [boiled]) and we had quite a bit of wastage due to a lack of shields, drip trays, filters, etc. I'll design these and manufacture them myself or, more likely, have local artisans bang them out. Plus, we need to build a boiler to clarify the oil (heat it enough to kill off enzymes that give a smell and shorten the shelf-life). Lastly, we need settling tanks, drums, etc. In all, we still have a solid month's work ahead of us before we have food-grade sunflower oil; but believe it or not, we are on the downhill side of the work, as we started from the ground in January.

All for now ... back to the mill.