Appendix 2
The Sugar Mill Machinery at Yengarie
The Tooth Designed Sugar Mill Machinery at Yengarie
(The Prototype for the Millaquin Mill)
The following details provide an edited version of a report contained in the Maryborough Chronicle, Wide Bay and Burnett Advertiser of the 18th of November 1869:
At its inauguration, and by the standards of the day, the crowded and complicated Yengarie mill machinery appeared to be of enormous proportions and was serviced by punts that delivered cane to the wharf from which it was moved by a cable driven tramway up to the factory. The crushing rollers were then fed by a table of boards attached to an endless chain onto which the cane was deposited from the tramway. The megass was collected from the sides of the rollers by similar tables and delivered to tramway mounted trucks for removal from the plant. The juice from the crushing poured into a lower tank and was then lifted, by a positive-displacement pump, into four raised, open urn-shaped iron boilers located near the mill’s roof that were heated by steam. On being raised to boiling point for the clarification process the juice was then drawn off into open, shallow tanks called subsiders and from there it descended into a large collector for delivery to the evaporator.
It was here that Mr. Tooth’s patent equipment came into operation. His evaporator was shaped like a tubular boiler placed on its end and was about fifteen feet high by six feet in diameter. To the one side of this were the air-pumps and condensers, and on the opposite side was the heater which consisted of a tube about seven feet high and one foot in diameter, through which the juice was carried by means of a force (positive displacement piston) pump and connecting pipe. The pipe ended at a distributor shaped like a huge watering-can rose. The face of this had over 2,000 perforations from which the juice descended in a shower on to the floor of the evaporator. It is then pumped from the evaporator’s base, forced through the heater and rained down again until, by means of constant testing, the consistence of the juice was found to be such as to indicate an adequate degree of evaporation.
The juice in the tube through which it passed was heated by injected steam into the surrounding small pipes and the heated juice was then boiled, in a partial vacuum, at about 160°F. The juice, now converted into a syrup, was collected from the base of the evaporator and drawn off into a reservoir from which it flowed into an ordinary vacuum pan, where the crystallization took place. The mingled mass of syrup and wet sugar was then run off into coolers and passed through the same type of centrifuges as were utilized in the conventional milling process to separate the granulated sugar from the syrup. In passing through the centrifuges a little water was sprinkled on the sugar to coat the sides of the swiftly revolving cage, thus assisting the cleansing and de-colouring of the sugar. The separated syrup was then returned to the heater to mingle with the fresh juice and to undergo repetitions of the whole process until the sugar was completely extracted. A large quantity of water was needed to provide both the steam and the cooling water that was necessary to drive the mill’s machinery so that a force pump, located close to the creek and powered by a steam engine of 10 horse power, was utilized to deliver water to the factory. The large volume of water passing through the condensers was evidenced by the stream of hot water being returned to the creek. Some of the heat contained in the residual steam was recycled for use in the clarifiers to heat the juice in the evaporator, the vacuum pans and other equipment.
The total amount of power employed by the mill was equal to about 100 horsepower (HP). Overall, the 100 HP motive power was employed in drawing the cane trucks from the punts to the mill, in lifting water from the creek, in crushing the cane, forcing the juice to the top of the building, heating, exhausting the large evaporator, forcing the juice through the heater, exhausting the vacuum pan and giving motion to the centrifugal machines.
At the factory’s inauguration the clarifying and subsiding operations were carried on in the open air and, although only taking half an hour in all, Mr. Tooth considered this to be so detrimental that he intended, in the following year, to install a process by which the juice, from the moment it leaves the crushed cane until it is converted into sugar, will be protected from the atmosphere. The juice extracted from the crushing would then be fully isolated from the atmosphere until it was delivered as sugar at the conclusion of the treatment process with the moisture having been removed as steam.
Elsewhere on the site there was a substantial sugar refinery in the course of erection and the large iron retorts needed for the manufacture of the animal charcoal used in the refining process were then on their way for delivery to Yengarie. This would provide Messrs. Tooth and Cran with the ability to greatly extend the factory’s period of operation. It was proposed that the steam power, that would become available at the conclusion of the mill’s crushing season, could be employed in the manufacture of meat extract and in other subsidiary industries.