openspaceman

Yes 4000 but I no longer have access to a copier, photos any good? I cannot find the 3000 so could do with that too.

Blaming me now , I'd have dropped across to discuss things Too many points but the major one is that the drying needs heat, the means to transfer the heat into the barrel is restricted to the barrel walls and convection in the retort. Simple is good, so let's find a simple and cheap way

My point being that drying in the retort is very inefficient, especially as it slows the pyrolysis down, if you put warm oven dry wood in the retort how would the times compare? Which is why a continuous or batch sequential system is preferable (a bit like the way crematoria now work), The first retorts that Peter?? brought to Merryworth had two chambers, they appeared to be designed to hot swap cassettes so the offgas from one supplemented the heating of others. Pictures of the original Lurgi coal retorts seem to be this way. Yes too right on both counts, up to 70% of the heat in the wood is evolved in the offgas, the flame temperature of which is many times what is needed to pyrolyse the wood or dry it. Keeping the capital cost down is the difficult part, once the university got involved in ours the costs skyrocketed and the complexity made commercialising the concept to expensive.

Yes but not really for barbecue charcoal. Aldershot is a place where gunpowder was made for the military, alder could be ground to the right size to vary how quickly it reacted, alder buckthorn was favourite for fuses. Later I think they dried the granules of black powder into different sizes to vary the speed of detonation. Beech and Hornbeam were favourite for iron smelting, hence the copses at Leith hill, where you could see the charcoal hearths in the hillside prior to 1987 storm. The sandstone yielded the iron ore and the lime came from across the valley, with the Tillingbourne providing the power for the hammer at Abinger. Pine was used to co produce stockholm tar. I suspect the pyrolysis was at much higher temperatures for these processes to have a much higher proportion of fixed carbon. Barbecue charcoal tends to retain many less volatile compounds which is why it lights easier and smokes, Charcoal made at 900C is nearly pure carbon, doesn't smoke and the yield is only 15% of the original dry weight of wood.

At these higher temperatures radiation becomes important, thermocouples read low because they are constantly radiating heat away unless in equilibrium with the walls of the surroundings. This doesn't matter if you are just comparing burns. The obvious one is to have a smaller fire underneath and a more conventional design with a grate. The power is then controlled by the primary air and the secondary air is entrained by the primary combustion. As I keep saying you need more time to dry wood than to pyrolyse it, once pyrolysis starts its self sustaining as long as the temperature doesn't drop. At this stage lots of offgas is evolved and most of these simple retorts pipe the gas into the firebox where it adds to the heating just when you don't really need it or you flare it off wastefully. When I built one of these after seeing them at the merriworth estate and being developed by Robbie Webster I had two pipes out of the retort with one cap. The idea being to take the offgas under the retort when needed and flare it when not. I intended to use a bimetallic strip to open and close the flues but we moved back toward kilns (having moved away because the Viper produced poor charcoal for barbecues).

Which is too hot. In fact the picture shows the steel has burnt and that is iron oxide flaking off. I can't see the need for the firebox temperature to be much above 550C. Can you not line it with tiles or fire brick. I was told a slurry of clay and milk could be applied to protect steel, I was not very successful with it but I probably did something wrong. In boilers the steel is often protected by the water bath and the grate by exhaust gas recirculation but these aren't practical here.

Steel loses about 40% of its strength at pyrolysis temperatures (say 470C on the hot side of the retort), flame temperatures with dry wood will be 1100C plus. Stainless is weaker than mild steel plus it is a poorer conductor ( so cannot get rid of its heat as well). Having said that thin mild steel manages quite well at 700C on the hot side if it's room temperature on the other, trouble is with a retort you have it hot on the flame side but you need over 450 on the char side. The thicker the steel the hotter the hot side stays.

Just because it's stainless doesn't mean it doesn't lose strength when heated just that it resists oxidation.

Our steel side LDV went on the weighbridge without driver and half tank of fuel at 2100kg

Actually if you run the winch tractor perpendicular to the line of extraction you can steer the stems by moving back and forth. I found 4 chokers per drum was about optimum, even though I would double choker two stems to one chain frequently (I tried rope chokers but the igland 4 tonne double drums snapped them too easily). Back in the day when I did first thinnings the trees were about 20 years old, seldom bigger than 6" diameter or 12m long, so the only damage was turning out of the rack and that tree would be felled last. Then the trees were at 5ft spacings and to make any money we had to cut a large selection of PSR and rustic poles, losing money on anything sent to pulp. The larger trees which were not wolves were less good for PSR and because of the price size curve being what it was also not big enough to produce bars, so there was no real advantage in felling them, they would be more valuable in later thinnings or final crop. Being idealistic then I reasoned that a geometric 1 line in 4 thinning would lose 25% of these trees with higher potential, so I would produce my rack at right angles to the planted lines, with the Holder and tongs I could skid stuff out without damaging the remaining trees as I cut and selected and formed my rack to avoid the better trees. Elsewhere the FC had largely caved in and were taking 2 lines out of 6 to allow volvo 868 forwarders to work as their target was for volumes of industrial wood rather than concentrating increment on premium stems. My efforts all came to nought as the plantations were bought by RSPB some years later and clearfelled to revert them to heathland. I realise if you are on a steep lope there is little option but to go straight up and down..

We knew the term and would call the bunch of logs a tush but tended to say skidded out. Long gone the days for me when I came blaring out of the woods with 8 half tonne larch trees, tip first behind the County, still got the machine though. In fact it was very versatile from second thinnings to big hardwoods but by 1984 I had succumbed to shortwood for softwood and fitted a grapple loader on the roof.

Thanks again, so it's only the most recent B+E that are restricted.to 3.5 tonnes.

1020kg If you are talking about my Jussi it's just not worth doing, other than perhaps moving the grapple loader onto the new road going trailer. The original poster was asking about legality but if the conversation is moving to practicality: I've not much faith in the idea of using a 4wd vehicle as a tug in the woods. I tried not to work further than 20 miles from home and at that range there’s not much journey time difference between 25mph and a road vehicle on normal roads but this presumes working from a yard at home, a luxury I never had. I left my tractors on site and over 30 years suffered considerable damage from theft and vandalism that I would not contemplate it now. The Jussi is ok for loading a transit to save some back breaking lifting, it is impractical for forwarding on other than amenity sites. A 100hp 4wd tractor will move 9 tonnes over reasonable ground and can comfortably extract 50 tonne/day, this saves on loloading costs for a modern forwarder capable of shifting 100+ tonnes/day There is scope for the smaller outfit as timber prices rise back up but not on sites where a harvester and forwarder are practical. The problem for small woods is that the harvesting cost is a major portion of the roadside price and modern harvesters and forwarders have crashed the harvesting cost which has effectively lowered the roadside price to below the harvesting cost for motor-manual cutting and tractor trailer forwarding.

I think you may be right, in real terms teeth are a lot cheaper than in the 70s, as is saw chain. I'm sure that it's not worth using a small grinder without some sharp teeth. If there are lots of blunt teeth with a lot of tct left on them going spare I'd be tempted to make a small mulcher, because they work until al;l the tct tip is gone.

Sounds about right, actually my Jussi comes in at under 750kg with crane I think, I would need to change the tyres though At 20mph (but it is probably 25mph if I can find an updated regulation) how much time difference over a road vehicle on a 10 or 20 mile journey? I used to drive between sites but nowadays the big problem would be leaving the kit in an unsecured area overnight. With the Jussi and Ferarri I used a 7.5 tonne beavertail but that increases costs. The ideal would have been a small tractor or ATV carried to site on the forwarding trailer behind a dual purpose vehicle, and off again at the end of the day. I've been considering this and it is doable within the 3.5 tonnes, On the road payload would be around 2 tonnes of wood but in the woods it would have a higher capacity. I would opt for a variable geometry between forest and road. This way you can carry all the kit and spares necessary in the towing vehicle.

Cheers for that.

If you are happy to write down pressure and flow readings and set the pressure by constricting the flow with a valve then a pressure gauge and Hydraulic flow indicator from webtec may be cheapest. I used these to prove the pump was cavitating on a tracked chipper.

This is an interesting one as in around 1975 I worked for an IH dealership, we delivered balers behind the works 3 ton truck. Now bearing in mind the 1986 C&U regs I quoted must have been superseded by the recent changes in allowed tractor speeds to 25mph for tractors without all round suspension you should be able to tow an ATA or trailer at the higher speed. In fact the 1986 C&U regs do not specify a speed for those trailers exempted from having suspension. However the over riding act is the Road Traffic Regulations Act 1984 and that limits these types of trailers/appliances without suspension to 20 unless these also were subject to the recent changes for tractor speeds The superimposed load on the tow hitch would have to be within the limits of the pin-hitch-drawbar and suspension limits of the vehicle. In the past I moved my unbraked Moheda 9 tonne trailer behind the LR110 but I wouldn't risk it now.

Unless it's towed by an agricultural machine your licence will determine the trailer weight, for most it will be 3500kg and that can have overrun brakes. The relevant part of 1986 C&U regs says "every motor vehicle and every trailer shall be equipped with suitable and sufficient springs between each wheel and the frame of the vehicle. " so no but I can see a couple of ways round using a walking beam. There are exemptions for ©an agricultural trailer, or an agricultural trailed appliance; (d)a trailer used solely for the haulage of felled trees; It looks like you may but you may be restricted to 20 or 25mph, depending on interpretation and whether the higher speeds now allowed have been applied to the C&U regs. You will require brakes on all wheels if carrying a load unless the trailer can be classed as an agricultural appliance.

Same as I think

First step would be to have the serial numbers on Arbsafe, then anyone who is suspicious of a saw they have been offered or in for repair can check online.

Weren't you going to check on how this right was lost? It doesn't affect me but what about those Land rover 5th wheel units?

Pre 97 they didn't specify the trailer weight

It was promoted for feedstock for the ARBRE gasifier that never got commissioned. The idea was that the brash would air dry in the bundle and could be stored outside on just a hardstand. I saw a rottne with the fiberpac baler working some pine tops on a heathland clearance. Much of the mineral ash is in the needles, buds and bark and on a heathland reversion it was a benefit to reduce the fertility, not so sure it would be on many forestry sites where the brash aids soil structure as it rots. It was promoted as using cheaper transport than wood chip in walking floor trailers so I wasn't aware of the problem of bits falling out of the bundles

With a kiln the fire is inside with the raw material being carbonsided and with a retort the fire is outside the container with the raw material inside.