January i, 1885.] THE TROPICAL AGRICULTURIST. 



57* 



IMPROVEMENTS AND ALTERATIONS IN THE 

 SIROCCO TEA DRYER. 



East India Club, St. James' Square, London, S. W. 

 December 12th, 1884. 



Sir, — Many tea gardens in Ceylon are just now at the 

 stage when it is ail important for the owners to decide 

 which of the various machines, offered for the different 

 processes in manufacture, is the best. 



As you possibly know, tea, and all appertaining to 

 it, has been my study for many years, and in the 

 fourth edition of my book* I discussed at length the 

 many tea machines. Among them I noticed the 

 " Sirocco Tea Dryer," but not very favourably, for I 

 there say " when it came out it was, I think, the beet 

 machine (dryer) going. I doubt much that being 

 the c^se now." Bnt quite hitely at the inventor's 

 (Mr. Davidson's) request, I have seen the great alter- 

 ations made by him in the Sirocco, and the result is 

 that I am sure no planter, in want of a dryer, should 

 decide on his choice, until he has heard and enquired 

 about the new Sirocco. Mr. Davidson has dunug the 

 last month, been exhibiting it at 60 Gracechureh St., 

 and, that, I am not singular in my estimation of its 

 merits is proved by the fact that he has sold upwards of 

 sixty of the new machines to firms and individuals, 

 well conversant with the necessities for a dryer ! 



The old Siroccos had more than one fault. 



1. Unless great care was exercised burnt tea was 

 sometimes the result. 2. The quantity turned out was 

 small. 3. The tea was not dried entirely by hot air, 

 but partly by the heat given out by the hot iron. 4. 

 The iron of the machine, exposed to the greatest heat, 

 buckled out of position and burnt away. 5. The em- 

 ployment of an air chimney had drawbacks, it carried 

 off much of the hot air, not only out of the machine but 

 also out of the factory, and the chimney passing up 

 through the roof was objectionable. Each and all of the 

 above faults have been done away with in the new 

 machine, and as far as I can judge, it possesses all the 

 necessary conditions for turning out, at a strictly 

 moderate cost, high cla?s teas in considerable quantities, 

 tired to the exact degree necessary. 



It is not easy to describe a machine without diagrams, 

 still I will make the attempt. In outward form it re- 

 sembles the capital letter T with the right projection from 

 the top of the vertical stem omitted, 'the stove is at 

 ba=e ot the vertical stem. The tea is dried at top of 

 the left horizontal projection by hot air, which ascends 

 the said vertical stem, and then runs along under two 

 lines of trays to the end of the said horizontal projec 

 tion. The trays are eight in number. The feeding side 

 is at top of the vertical stem. When all charged and 

 placed, there are four above and four below. The upper 

 iter is poshed forward one step when each tray with 

 new roll is introduced at the feeding end into position 

 No. 1, and on arrival at the other end into position No 4, 

 the further introduction of another such tiay pushes 

 No. 4 out, which is then transferred down into the 

 lower slide, and pushed into position No. 5. Thus, 

 each tray makes one journey forward and back ataiu, 

 along the horizontal Hue represented by the left" top 

 projection of the said capital letter T. When it has 

 made this journey, it is of course once more at the 

 feeding end, but in position No. 8. 



At each extemity of the said horizontal Hue, the metal 

 slides or rails, on which the trays run, project 2i feet 

 beyond the flue. This at the farther ei.d erabl.s the 

 boy who works there to pull out the tray with half- 

 fired tea on it, re-spread it and introduce it conveniently 

 into the lower slide. At the feeding end it serves 

 two purposes. It allows the tray to be pulled out 

 and the tear examined. Asa rule when it (the tray) 



* Tea Cultivatiou and Manufacture by Lieut.- Col. Money 

 4th Edition. Sold at Observer Office, Colombo. 



arrives at this last, or Sth position, the tea on it 

 is sufficiently fired, But if not so, it is again re-spread 

 and put back again in No. 8 position until it is 

 done. The other purpose anel a most important one 

 constituting one of the great advantages of this new 

 type of Sirocco is as follows : — 



When the tray with the tea finished or nearly so 

 has arrived at position No. 8 and is ready to tike 

 out, it follows of course No. 1 is empty. The tray 

 to fill that position with new wet roll on it is first 

 placed there aud after this is done the lower tray in posi- 

 tion No. S is pulled out to be examined as described. 

 The current of hot air which ascends the vertical stem 

 and is then hotter than at any time after (that is to 

 say hotter then, thun later when it runs along under 

 the trays) touches nothing (the space below being now 

 clear of tray No. 8) until it impinges on the said wet 

 roll on the tray in position No. 1. It does this at a 

 temperature of 350°, and consequently immediately 

 arrests further fermentation. All planters know that 

 stopping fermentation at the right ti ne, aud suddenly is 

 one of the main points in Tea Manufacture, and one of 

 the great virtues in the new type of Siroccos is its 

 excellence in that respect. 



The trays are worked or pushed along by one man 

 at the feeding, and one boy at the farther end. The 

 boy of couise has only to transfer each tray after 

 it has arrived in position No. 4 to position No. 5 in 

 the lower slide. 



I have thus detailed at some length the way the 

 trays are woiked, but I should trespass too much on 

 your space, did I dwell as fully on all the other 

 parts of the machine, and its workings. What re- 

 mains 1 must state hereafter. In the machine I am 

 describing hot air alone is the agent for firing the 

 Tea. By very ingenious contrivances the following 

 is attained :• — 



1. A'hether coal or wood is used the said hot air 

 is quite free from the smoke or fumes of the fuel. 



2. Whereas in the old Sirocco, the sides of the 

 machine gave out and wasted much heat, in this new 

 type the sides are comparatively cool. The hand 

 cau be placed on any part without inconvenience. 



3. The heat which in the old type was given out 

 and lost from the sides of the machine is now trapped 

 in chambers formed by the present double sides, and 

 is absorbed by air currents admitted at the base of 

 the said chambers; and the hot air thus produced forms 

 a continual ascending current and is admitted into 

 the upper part or the vertical stem. Thus, instead 

 of being wasted this spare heat is used as an addi- 

 tion to the main hot air current for drying the tea. 



4. Whereas again in the old Sirocco the ascending 

 currents of hot air were often not eciual in temperature 

 and thus the tea on one part of the tray might bu 

 overtired while other parts were not done enough ; 

 by an ingenious arrangement of "hopper shoots : ' 

 in the vertical stem, the possibility of this is now quite 

 avoided. The said ascending currents as they leave 

 the vicinity of the stove are still often not equaliin 

 tempera 1 ure. but before reaching the tea they aie all 

 forced to mingle together and become uniform. 5 

 So much of the hot air current as passes through 

 the wet roll on tray in position No. 1, and is con- 

 sequently charged with much moisture is not used 

 again at all. In other words, the moisture from that 

 tray, is not, as with some dryers, carried on to another. 



(5. In ro place does the hot air current pass 

 through more than two trays, and a great point is 

 that m each position it passes through the drier 

 tray first. 



7. After passing iluough two trays it goes upwards 

 into the Factory, at a temperature of 120°, and 

 js available to help in leaf withering. 



S. The chimney is attached by a flue and bend to 

 the base of the machine, and may be carried up the 



