FORTY-SECOND ANNUAL CONVENTION 299 



factory results cannot be had unless the exhaust pipes leading 

 to the pasteurizer are of the proper size. A one and one-half 

 inch or larger steam pipe should be used when heating with ex- 

 haust in the continuous pasteurizer, and it is necessary to have 

 the steam inlet on the pasteurizer of the same size as the pipe 

 carrying the exhaust steam. If the exhaust pipe and steam in- 

 let on the pasteurizer are large enough, it will be less trouble to 

 keep a uniform temperature than when live steam is used, be- 

 cause the exhaust steam does not vary like the pressure on thq 

 boiler. When the pasteurizer is some distance from the engine, 

 it is necessary to use a larger exhaust pipe than when the steam 

 travels a shorter distance. 



Where the vat method of pasteurization is used, the ex- 

 haust steam can be piped direct from engine to water tank at rear 

 end of ripener. A two inch pipe will usually be large enough, 

 and the end that is under water should be capped and perforated 

 with about 30 or 40 five-eight inch holes, which will reduce the 

 noise to a minimum., 



If the oil from the exhaust steam is objectionable, because 

 of coloring the floor, an oil trap may be used near the engine, 

 This trap will catch practically all the oil, leaving the exhaust 

 nearly as clean as live steam. 



Creameries using one of the exhaust water heaters described 

 in our Bulletin No. 54 may also use the hot water from this heat- 

 er for pasteurizing in the ripener, provided they have occasion 

 •to operate the engine a short time before pasteurizing, to heat 

 the water to near boiling point. This hot water can be circulated 

 through the ripener coil by gravity, and with a pump it is re- 

 turned to the heater. Nothing smaller than 1% inch pipes 

 should be used in the pipe lines between heater and ripener, as 

 too small pipes do not allow enough hot water to pass through 

 the ripener coil, and the result is slow and unsatisfactory pas- 

 teurization. 



Sweet Cream. 



Sweet cream of a fair average test may be pasteurized by 

 either the continuous or the vat method without any trouble 



