Oct. 2, 1920.] Agricultural Gazette of N.S.W. 709 



Utilising Waste Heat in Butter Factories^ 



0. C. BALLHAUSEN, Dairy Instructor. 



The rapid increase in the price of fuel, whether coal or wood, and the further 

 increases that are probable at no distant date, makes the efficient use of fuel 

 at butter factories of the greatest importance. The production of power (and 

 of the heat that produces power, whether by steam or suction gas plants) is 

 always one of the largest items of expenditure. Since the advent of the 

 pasteurisation of cream at practically all our butter factories, this item has 

 been still further enlarged, and any means by which the outlay on fuel can 

 be curtailed will commend itself to factory managers. 



In recent years considerable attention has been devoted, in some places, to 

 the power departments of butter factories, and many experiments with fuel 

 and with boilers, and in the arresting and use of waste, or exhaust heat, have 

 been carried out. 



Probably no factory lends itself better and in more ways to the practical 

 use of the heat, in exhaust steam or gas, than a butter factory, where 

 large quantities of hot water are required all day. As this exhaust heat 

 can be secured and used again, it will be seen that to allow it to escape 

 unused is simply to waste a valuable by-product of the factory. Many 

 of the larger factories do make use of most waste heat, but there are still 

 many that make no effort whatever to supply themselves with an abundance 

 of hot water at a very small outlay. 



It is by means of hot water chiefly that the floors and drains of factories 

 can be kept properly cleaned, apart from the washing of cream cans, all 

 utensils, and a certain form of pasteurising, &c. 



The use of direct live steam from the boiler for the heating of water for 

 factory purposes adds heavily to the fuel bill and is therefore expensive. It 

 is possible to minimise the use of live steam, and effect a big saving in fuel 

 costs by utilising exhaust steam for the heating of boiler feed water, washing 

 water and pasteurising. For the heating of boiler feed water there are 

 several useful attachments on the market, all making use of exhaust steam 

 for the purpose. 



In small steam plants it is estimated that nearly 90 per cent, of the heat 

 in live steam remains in the exhaust. If it were possible to collect the whole 

 of this waste heat, and use it for heating boiler feed water, wash water, and 

 water for the pasteuriser, the capacity of the boiler would be nearly doubled, 

 and the fuel bill reduced by nearly one-half. 



For every 10 degrees Fah, that feed water is heated, approximately 1 per 

 cent, less fuel is required to generate a given amount of steam ; and for each 

 10 degrees Fah. increase in feed water temperature, the boiler capacity is 

 increased approximately 1 per cent. When hot water is used a constant 



