A Cheap Hot-Air Drier

A cheap and apparently effective hot-air drier has been constructed by Mr. A. A.

Bensley, of the Methodist Mission, Solomon Islands. By the December “Malaita” there arrived in Sydney a sample of the copra from one of Mr. Bensley’s driers: and Messrs. Burns, Philp and Co. Ltd. report of it, “it is undoubtedly a very good quality hot-air dried copra.”

Mr. Bensley, who at present is in Australia, very kindly has supplied us, for pub lication, with the following description of his drier.

EVERYONE has his own ideas about driers; and many are experimenting with the idea of making quality copra without going to the expense of an elabor ate plant. Here is a simple idea for a drier which does produce copra of good hot-air-dried quality.

On most Islands of the British Solo mons there is an abundance of light coral stone. This is quite excellent drier material. The idea the writer had in mind was to build a drier without costly material, and which could be built by natives in their own villages, if any one was interested enough to undertake a little supervision and get them going.

While the natives are poor the trader is poor. If the natives could be awakened by a new idea, it will be to the good of the trader.

First of all, select a spot where there is plenty of this stone handy, and, if the spot is sheltered from prevailing winds, so much the better. Put in your posts and bearers. Size is a matter for the builder, but the one under discussion is about 1.0 x 20. After the heavy timbers are In, start building with this soft stone, making the base about 4ft. wide, enclos ing the wood work, touching the posts at the base. Put in a couple of flues at each side, by making a strong box of any rough timber, about six inches square, inside measurement. Put these on the ground opposite each other, and build over them.

Taper the walls up, to about 7ft. high.

Mention should have been made of the fact that the bearers are at a height suf ficient to give the tray a 6ft. space from the fire.

The stone wall is tapered up to about Ift. wide at the top. Two doors are put in, just wide enough and high enough to enable a boy to push in a bag of firing.

These doorways should be constructed with some care as to fit. The one herein described has posts and a heavy piece of rough timber on top, so that the wall may be continued upwards.

Here is the secret. The wall was built like a double wall and lumps of soft stone thrown in and pounded with a hammer.

This cuts out draughts and leakage of heat. For the tray, native material was again used: thin palm laths. A layer of this soft stone was then put down on the floor. Now you have something not at all unlike an oven.

Over the whole thing a leaf house was built, wide enough to leave plenty of room for the firing, and, with the two doors at opposite sides from the doorways in the stone wall. These doors need not be nar row or closed up. This cuts out direct draughts. This is a house complete with walls and not merely a roof.

On the top of the stone wall some rough bush timber was placed and made a fix ture and a few pieces were put cross ways, to enable boys to inspect the copra and move about without the necessity of disturbing the layers of nuts.

Now the drier is complete. For the first fire, of course, some dry shell is needed and it is not a difficult matter to put through a cooking of husked nuts on a smoke drier in the native fashion.

Most people agree that smoke dried copra, cooked in the shell, with some attention paid to the firing up and treatment, is better quality copra than smoke-dried copra that has been cut-out in the pad dock.

As has been emphasised in connection with all these driers, absolutely dry shell is necessary.

The nuts are husked and split. This drier takes about 2500 good nuts. They are arranged on the tray in layers, with the cup upwards, care being taken that they are stacked loosely and not allowed to cup one inside the other. It does not matter much how many layers there are, within limits. Four or five could be accommodated.

When so arranged the fire may be lit.

Of course, it is as dark as the present depression inside the drier, but it is not a

difficult matter to light a few dry shells outside and carry them inside to see the work by. In this drier no particular at tention was given to the placing of the shells for the fire. They were thrown down roughly in the form of a snake, not bunched thickly in one place and out of contact in another. What was done most frequently was to follow the walls along inside, keeping a safe distance from the posts and joining up across in a few places. Singly arranged is a waste of time. Light at each end and, when well alight, close up the doors in the stone wall. Let this burn out and give it about an hour and repeat the process. A third fire will be necessary and perhaps a fourth, especially the first day. The drier will retain the heat for quite a long time.

The stone on the floor gets nicely heated and it will be as hot as tropical sunshine for some hours after the fires are out. On the second day perhaps three fires will be found necessary: morning, midday, and late afternoon. One has to discover for oneself.

On the morning of the third day these half-nuts are easily shelled and the half baked copra is parked at one end of the drier in about a quarter of the space it formerly occupied. The very soft pieces are put at the bottom. Now 2000 more nuts may be put up and the heating car ried on for two days. At the end of this time the first lot should be hard and white and ready to come off. Judicious sorting may be found worth while. The second lot is now treated as the first, and a third lot put up, and so on. A drier of this size, worked in rotation, would produce close on 50 tons a year.

Note: Measurements given above are from memory and there may be a little either way. The nuts are not counted with absolute exactitude.

This drier has produced good-quality heat-dried copra, which keeps well. Of course, some care must be exercised afterwards. The copra is not thrown into a damp leaf-building, but into an iron building with a good floor. There is quite a bit of warmth during the daytime in such a building.

There is always another side; and we will not claim for this drier more than it has performed. At any rate, it is cheap and it is therefore good—within limits.

There is negligible fire danger, unless the firing is bunched. It will serve' a small place admirably, and there is no reason why another one or two could not be built at intervals to deal with a larger place.

What is more to the point, is that anyone with a bit of trying might get the natives busy as a much better price could be given.

Of course, the Government should have done something like this ages ago, and given an interested trader a certain length of coastline, where poachers would be forbidden, as some kind of a guarantee; but any help of this kind never occurs to the Solomon Islands Government.

There are one or two things which will be noticed. The fluffy dust from the husked nuts gets well distributed inside the half-nuts when they are being placed on the drier and this gives the copra a slightly discolored appearance. Well, there is often an old or decrepit labourer about and there are plenty of ready-made small brushes on every beach —those seed affairs often used by the natives for shav ing brushes. Or, it is a nice little job for the planter himelf as he smokes a pipe.

A tap on the floor and a swipe make all the difference —that is if the planter wants an article that comes within a short distance of being equal to that pro duced by the most elaborate kiln. Of

course, one does not need to stroke every piece with a silk handkerchief and kiss it “Good night.” Much of the copra will not need any handling.

Finally, there is plenty of room for modification as this drier has not been tried out scientifically. Doubtless the idea could be improved on.

And again, finally: Up to the present, this drier has not produced quite enough shell for itself. Anyone trying the idea out properly may probably see the reason for this. However, as was stated above, good smoke-dried copra in the shell is good copra, obviously, and there are often plenty of rough and growing nuts about the place. Unsprouted nuts are admittedly the best for good quality hot-air copra.