394 REPORT— 1894. 



II. Separating Method. — Attempts have been made to ascertain the 

 amount of moisture in steam by measuring the quantity of water trapped 

 in a separator, between the boiler and engine, through which the whole of 

 the steam passed. Probably such separators are too small relatively to the 

 amount of steam flowing through them to detain the whole of the moisture. 

 Mr. G. A. Barrus, in using a small separator in connection with a super- 

 heating calorimeter, noticed that very nearly the whole of the moisture 

 was caught by the separator. In that case the quantity of steam passing 

 through the separator is small.' More recently Professor Carpenter, of 

 Cornell University, has brought out a form of separating calorimeter of 

 small size which can bo applied almost anywhere on a steam pipe or boiler, 

 and which can be used with very great facility. 



The separating calorimeter (tig. 1) consists of a vessel. A, about 

 12 in. x3 in., consisting of an inner chamber and a jacket. The steam 

 from the steam pipe, S, passes first into the inner chamber, where the 

 moisture is separated, and thence into the outer chamber. The separating 

 chamber is consequently almost perfectly protected from radiation. As 

 the water accumulates in the inner chamber its level is shown by a gauge 

 glass, g, and the amount can be read off on a scale. A very small orifice 

 at the bottom of the outer chamber regulates the amount of steam dis- 

 charged. The steam as it escapes passes through a flexible tube to a 

 simple form of condenser, C. The increase of weight of the condenser in 

 any given interval of time is noted, and the amount of water deposited in 

 the same time in the separator. If x is the dryness fraction of the steam, 

 IV the weight of water caught in the separator, and AV the weight of steam 

 condensed, 



x= ^^ 



W-i-w 



The scale on the separator is graduated to ^J, ^ths of a pound. There 

 is also a gauge glass and scale on the condenser, graduated to read pounds 

 and tenths at a temperature of 110° F. But as the variation of volume 

 of the water with temperature affects the readings considerably, it is best 

 to weigh the condenser, or, at any rate, to determine a correction of the 

 scale for temperature. Professor Carpenter states that the dryness of the 

 steam after passing the separator was tested in the laboratories of Sibley 

 College by several observers, and with steam carrying from \ per cent, to 

 60 per cent, of moisture. In every case the separation of the water from 

 the steam was complete and perfect.* Other tests have been made with 

 moderately dry steam, using the sepai'ating and throttling calorimeter 

 simultaneously, and the results were practically identical. The instrument 

 is very simple to use, and requires no pressure gauges or thermometers. 



III. Condensing Method. — Suppose a known weight of the steam con- 

 densed and its total heat determined. By comparing this with the total 

 heat of an equal weight of dry saturated steam, according to Regnault's 

 Tables, the amount of moisture in the steam can be determined. 



The apparatus designed and used by Hirn in the Mulhouse trials in 

 18-59 (fig. 2) is, so far as we know, the most convenient and perfect 

 apparatus hitherto used in trials of this method. It consists of an iron 

 vessel, C, about one foot in diameter, furnished with a loose cover. This 



' See Barrus, Boiler Tests, Boston, U.S.A., 1891, p. 258. 



'' See Experimental Evgiiieering, by R. C. Carpenter, New York, 1892, p. 400. 



