agg221

I'm not quite sure on this one. Certainly if you measure efficiency in burn time then warm, oven-dry wood would take less time to process. However, if it doesn't reduce the total cycle time (inc. heat up and cool down) by enough to get a second cycle in a working day, assuming you want to stick with single shift working it won't increase productivity. However, drying the wood to this level will take longer or require more energy input. In an ideal world, where the off-gas was being productively extracted you it would pay to run with the driest wood possible, however in current systems where there is a surplus of gas, it could be argued to be more productive overall to burn the gas to dry the wood, ie to start with the wettest wood in the retort that you can still process in a day. The measurements we took suggest that at standard retorting temperatures you don't get the water-gas shift reaction so you don't reduce yield by doing the above. Batch-sequential definitely has advantages as you are using the waste heat so don't suffer time penalties for drying. Continuous brings different issues - it is typically used at much higher temperatures for gasification, so is deliberately inducing water-gas shift to achieve H2 and CO output rather than charcoal. Universities are good at understanding fundamental concepts, ie working out why something happens. They are generally not so good at the commercial side. The consortium we are working with is purely industrial (apart from us - we are a commercial research and technology organisation) and everyone just wants to make it work, technically and financially. Everyone accepts that the markets will be niche, but niche commercial is still commercial. If you're interested, the public summary of the project is here: http://gtr.rcuk.ac.uk/projects?ref=132408 Note, in the course of the project we have established that internal combustion is more cost-effective than a Stirling engine and within the relatively small project we have focussed more on charcoal and firewood drying than on agri-waste to biochar and grain drying, but the principles are transferrable. Alec

My grandfather was too old to fight in WW2 so he volunteered as a fire warden at Chatham Dockyards. Chatham saw a lot of air raids, partly because of the dockyards and also being on the route up the Thames to London, so quite a lot of ordnance came down, which sometimes ended up in the collections of small boys. Granfer had an insurance round, which meant he met the mothers of said small boys, who generally didn't appreciate their sons' collections. We don't know whether it was the fact that he was a fire warden, or that he lived out on 9 acres of woodland, or that he was just a hoarder but somehow he ended up by the end of the war with a fair amount of live ammunition including tracer bullets etc. My grandmother wasn't too happy about this, so at the end of the war she told him to get rid of it. This was done on bonfire night, where he let the whole lot off. The highlight of the show was a 4" shell, where he waited for the fire to die down, embedded a cast iron drainpipe in the embers and dropped the shell down it - when the pipe got red hot the shell went up. My grandmother's elderly aunt who was staying with them at the time declared it to be the best firework display she had ever seen. Mum, who was born a couple of years later, remembers still finding bits of shrapnel from the shell embedded in the trees probaby 10yrs afterwards! Alec

What I described should be able to be made for the cost of the bearings and threadlock, maybe the rod (if you can't scrounge some from the scrap bin of a local engineering works) and the large sized drills if you don't have them and the same for the bolts. If I had CAD here I would just draw what I am talking about - once you've put up a picture I'll have a go at sketching something. Alec

You can retro-fit, but you might find by the time you have made all the bits it would have been cheaper and a lot less grief just to buy one! A starter for 10: Assuming you do not have access to machine tools, I would start by accurately measuring the diameter of the centre sleeve in the wheel and buy some rod to fit - it doesn't matter what as it will not be running on this surface so probably aluminium would be the best option. I would then take the rod to your local bearing supplier and get two sealed unit bearings which are a good sliding fit. I would make two blocks of wood or plastic, one for each side. They would be square, and about 2cm bigger across than the outer diameter of the bearing, and thick enough to embed it in. I would find the centre (draw diagonals) and then drill a hole the outer diameter of the bearing so that it can be pushed in, using either a flat bit or a holesaw depending on the size (either can be had cheaply on ebay if you don't have them). I would want to fix the blocks with four fittings, one in each corner of each block. Fixing method for the blocks would depend on available tools, the internal clearance between the wheel and the case and how much hassle I could be bothered to go to. Simplest would be to use plain bolts, pushed through from the inside (you really don't want to try to get the nuts in there!) and then tightened up from the outside. Neatest would be socket head cap screws rebated into the blocks, running into tapped holes in the case. Having figured out which fixing, I would drill clearance holes in the blocks, in each corner (8off in total), sized as required. I would cut the axle to the length across the outside of the cage, plus the thickness of the two blocks, plus 2mm. I would also buy some threadlock. I would then work out the hole locations on the case by pushing the axle through, pushing the bearings onto the blocks and sliding these on and marking the case hole positions through the holes in the blocks. Holes would be sized depending on whether they are to be clearance or tapped. The final assembly sequence would be to insert the bolts from the inside first (if using that method) then the wheel and insert the axle through it. I would push the bearings into the blocks, having first applied some threadlock, leaving them just back from the mating surface of the block to allow them to run clear - let the threadlock set before going any further. I would then slide the blocks/bearings onto the axle and temporarily bolt up to check all runs smoothly. Finally, I would slide the blocks back off, apply some threadlock to the axle and bolt back on, setting the position up to allow free running. There are probably more elegant solutions to dealing with end float than threadlock, but they are a lot more complex and probably require machining capability. Any advances? Alec p.s. can you tell that part of my background is design engineering.....

We run up against this sometimes. Totally different industry (R&D, failure investigation and consultancy for engineering in my case) but a similar problem in that on small jobs the value added to the customer (what you can charge for) does not offset the cost of the necessary non-value add. As an aside, these terms come from lean manufacturing but the principles can be applied to efficiency in just about any business. The tone of the email from the church warden suggests that he understands the issue, in which case I think I would be inclined to have a very open discussion, indicating that the cost of the paperwork is removing any profit from the job, but it will for anybody who does it properly, and see what he says. There are two possible routes forward that I can think of (I have used both under similar circumstances, where a sensible discussion can be held) and he could probably be steered towards either, depending on your preference. 1, increase the price to cover the paperwork side - not unreasonable as unless you have stated otherwise it would be reasonable to assume that your quote will not be held forever and you are 4mnths and counting. 2, hold the quote but get it agreed that your paperwork will remain on record for future jobs across the diocese. This gives you a competitive advantage, effectively equivalent to a preferred supplier, particularly if the church warden is in a position to put the word about to other churches. Knowing that there will be a certain cost of this type of work, adding a small amount to any future jobs (e.g. charging £100 rather than £80) would allow you to recover costs. Alec

Slightly off topic, but one of my ancestors was one of the original iron masters in Surrey (Warren furnace at Hedgecourt). Alec

It will be second cut this weekend. Ride-on mower has seized apparently so I will be using the no longer self-drive rotary to cut 1.5 acres. This will not be one of the more enjoyable parts of the weekend. Alec

Best way round this is to fix the thermocouple against the relevant wall. If you want to measure burn temperature (most useful for controlling product) it goes inside the vessel but if you want to understand what is going on you need it on the outside wall at the hottest part. The easiest way to fix it is to weld a tag on to slip the thermocouple behind but you could bolt it on instead, so long as you either drill and tap blind or you seal the holes over. For your set-up it may be easier to fix it to the SS support bar instead. My very limited knowledge of practical retort operation relates to the Exeter, from TVI (inc. observing a burn) and from the manufacturers who also operate one. The heat-up phase to the point where the off-gas is combustible appears to be a couple of hours and the retorting phase appears to be around 6hrs, during which there is still drying going on (water is still coming off) but the reaction is self-sustaining. You therefore do want the heating, but you do have an enormous amount of surplus gas and it would be handy if you could have had it earlier! That said, it appears to take a very modest amount of wood to get things going. The more interesting thing for us is looking at using the surplus gas productively in a cost-effective manner. Alec

Some very radical changes to the apprenticeship system came into effect this week. See here: https://www.gov.uk/government/publications/apprenticeship-levy-how-it-will-work/apprenticeship-levy-how-it-will-work and more importantly for most people on arbtalk here: https://www.gov.uk/government/publications/apprenticeship-levy-how-it-will-work/apprenticeship-levy-how-it-will-work#non-levy-paying-employers These have gone through very quickly and nobody has quite worked out how to implement them yet, but for most businesses which want to take on apprentices this will probably turn out to be a very good thing. Alec

Stainless starts off with lower strength than mild steel, depending on which value of strength you measure, but it retains its strength better at high temperature, particularly its creep strength, which is slow, gradual movement under relatively low loads, so it will be stronger for a given thickness than mild steel. For supports, where you aren't trying to get heat through, the low thermal conductivity isn't a problem. Alec

Tor Coatings in Birtley used to make an excellent solvent-based primer for galvanised surfaces which doesn't need an etch primer. I used it on my galvanised land rover chassis with no degradation ~6yrs later. They never advertised it so you would have to ring and see if they still do it (my can of it has no codes on). The advantage is that it's black, so it overcoats easily with a coat of tractor enamel for a long-lasting finish. Alec edit: found it - it was always difficult to locate as it wasn't listed properly, see here: http://www.decoratingdirect.co.uk/viewprod/t/TORGALVPF/

Do you know what wood they are, and are they treated? If treated, they are not a good idea for firewood. If it's something durable I might be interested in some. Alec

Looks very prunus-like to me. Probably common plum (Prunus domestica)? Alec

I think my bigger concern with lining is that water will inevitably run round the edges and get trapped. I think you are likely to then find that the rate of corrosion outstrips the rate of wear. Alec

Glad to hear it's working. The linkage on these saws is bits of wire which can sometimes get slightly trapped in the loops, causing them not to move. Not that it is your current issue but it is possible to put the whole air filter base in with the choke wire loop trapped the wrong side and only find out at the end (guess how I know this...) You can only really tell whether the tuning is right or not once the saw has warmed up. Alec

OK, let's think about what we know. It coughs when the choke is on. That means you have fuel and air at near the right mix, and a spark under compression. It also means you are pulling it over fast enough. When you take the choke off, it doesn't start or even cough, but the plug ends up wet. Some thoughts. Firstly, there are two levers on the back of the air filter cover - one for the choke, the other for the on/off switch. You are leaving the on/off switch in the on position? Secondly, what happens if after it has coughed you set half-throttle, or ideally have someone holding the throttle open, and pull over again without taking the choke off? If it is set too lean, it will start and run happily when choked but not unchoked, as you will then have the mix right. Thirdly, have you had the air filter off and had a look at how clean it is? If it's very blocked they can be extremely difficult to start. If you can't see through the flocking when held up to the light it needs a good wash out. Alec

Have you tried taking the plug out and pre-heating it with a hot air gun (or blowtorch if you are careful not to get it too hot) and then sticking it straight in and starting? Alec

No, they trade huge volumes at very low fluctuations - the region of pence to tens of pence. The big fluctuation which hit us was the political uncertainty in Ukraine. Ukraine grows a huge amount of grain which was traditionally supplied to Russia. With this market gone, the European market is flooded and prices are down. Alec

NWOBHM for me

I certainly would! Not after a huge return, but it would be nice to know that I would usually make a modest % profit. This is a big issue. It isn't helped by other factors beyond anyone's control such as the weather of course, but the fluctuation really is bad. As an example, our first crop was winter wheat, planted in autumn 2013 and harvested August 2014. There were delays in the land purchase and we had to get an access agreement in place. My contractor went ahead at risk and we got ours in in the last week of November. The remainder of the land was sold to a local farmer who was a bit slower off the mark and his went in the following week. It then rained. That time difference was enough to mean that we got away with it, he didn't and had to re-sow the lot in spring. We were later than ideal, part of the land was already too wet to drill and the yield wasn't great - total production 9.5t, sold at £153/t. Including SFP we made a net loss of £30. The following year we also grew winter wheat. We had time to plan, chose the best variety for the land, a high yielding, high protein milling wheat and everything was run to textbook timing. We also increased inputs, resulting in a yield of 15.5t. Unfortunately the inputs, designed to get high protein levels to obtain a premium on the price as it could be used for bread, were not effective as it was a dull but dry summer so the plants couldn't take them up. That meant we stayed on the normal pricing but the cost of production was up. At the same time, the price fell to £100/t so the whole crop value was less than the previous year! There was also no SFP as it was after CAP reform. At current prices we would be on for a net loss of ~£500. 18mnths later it is still sitting in the barn, waiting for the price to rise. Alec

In effect, but not voluntarily. The threshold was moved to a minimum holding of 5ha and ours is only 1.8ha so I no longer have the option. Obviously I am not trying to make a living from it but I prefer to keep the land farmed so I have transferred the entitlements to our neighbour (foc) rather than them just disappear and we carry on. It is run on a proper commercial basis and is small enough that I can afford the loss Our position has given me a fairly good insight into the economics. Our land is bounded by roads and a river so you couldn't use larger plant by merging it. It is not great quality - lower end of Grade 2, but the circumstances do give me an opportunity to see fairly clearly how much of an improvement I can get by working on the soil structure with techniques such as green manuring, mulching with woodchip (hence my constant availability as a tip site) and adding biochar when I can make/get it. It's a long-term experiment. To give a context, this year's crop of spring wheat went in today (Group 4 feed wheat KWS Alderon) and improvement to the soil so far is marginal so I would be surprised if we can exceed 6.5t/ha, compared with an average quoted yield of 7.4t/ha. This would represent around £180 less return, which is likely to be around the value of the loss, ie if we were at average yield we would break even with no subsidy. The world record is 16.5t/ha, which was achieved with far more intensive input but even so would make a decent return. We won't ever get near that but it will be interesting to see how far I can get. Alec

Yes - my 076 doesn't have one and I generally don't use the ones on the 070 or 090 as they are too difficult to reach as they don't pop in. If it is easy to pull over with the spark plug out then it is not an issue with alignment of the fuel tank such as loose screws (common problem) or the bearings. You clearly have fuel and a spark and no reason to believe there is a lack of compression. I suggest tipping it up with the plug out to drain out any excess fuel that is now above the piston (which certainly won't help) and then warming the plug with a hot air gun before quickly putting it back in and trying to start it without the choke, just on throttle lock. If it's flooded, or there is a lot of oil that has worked its way past the piston whilst being shipped having been packed on end, this would clear it and it may run and sort itself out. Alec

If you have followed the whole procedure, that suggests the saw started (since the final step is releasing the throttle lock once the saw is running)? Alec

How far through the procedure did you get? After pulling over, is the plug wet? Saws of this age have a much more aggressive lead in to the magnet on the flywheel so you do need to be very decisive when pulling them over. Anything tentative and they will try to rip your fingers off! Alec

Obviously you are not required to satisfy the BPS demands if not drawing BPS, but very few of the regulations relate to the BPS. Those that do which I am aware of are mainly environmental (post-CAP), so headland sizes, areas of set-aside and minimum distance between cultivation and established hedges. Things I still have to comply with include buffer zones, use of approved pesticides, record-keeping etc. so you pretty much need to do everything anyway. The one advantage I get is that I do not have any restrictions on my rotation pattern, so am not suffering from the obligation to grow field beans (pretty much the only N-crop option in most places) which has knocked the bottom out of the market. Alec