Experiments made at the steam flour mills of Messrs. Hecker & Brother, N. Y
Journal of the Franklin Institute
Experiment~ on Hedcer's Slearn Flour .Mill. 299 ,t be obtained ; the loss from leakage and non-condensation is replenished with rain water. A separate Worthington steam pump is used to supply the condenser with cold condensing sea water, which is pumped up from the bay. The boilers are of the ordinary high pressure kind, cylindrical with return cylindrical flues, and having as an appendage a cross boiler or heater. 3'he dimensions of the entire machinery wilt be hereinafter given in detail. The
... iven in detail. The objects of the experiments were principally as follows, viz :--1. To determine the friction resistance of the engines and main shafting, and to ascertain the lax"" regulating that resistance in fimetion of the speed of the pistons : that is to say, to determine the pressure required to work the engines and shafting alone at any. given speed, and to ascertain if any increase of pressure on the pistons is required to work the engines and shafting, per se, at dittbrent speeds, and if any, what increase. 2. To determine the ratio of the increase of power required to grind wheat at inereased speeds, and vice versa : that is to say, for example, what increase of power is necessary in order ~o grind at twice the speed. 3. To determine the potential and economical evaporation by the boilers : that is to say, to determine how m6ch steam the boilers will supply in a given time, and how many units of weight of water are eouvetted irJto steam per unit of weight of fllel. 4. To determine the etfieieney of the condenser: that is to say, to determine what proportion of the steam supplied to it is condensed, aml incidentally, the amount of condensing water required, its temperature, and the temperature of the water fi~rmed by the condensation of the steam. 5. To determine the general condition and efficiency of the engines with regard to the proportions of their steam passages, their eut-offs, &e., &e., and the most economical maimer of using the steam. The following are the descriptions and dimensions in detail of the different machinery, viz : Engines.--'rwo horizontal direct aeting engines, warking upon the same shaft and at right angles to each other, their motion rendered uniforul by a fly.wheel and governor. At each end of the cylinder there is a short D steam slide valve, the two are joined by a rod and worked by an eccentric. The cut-off valve first used was a balanced four-way eoek~ connected with, and variable by, the governor; it was also variable momentarily by hand ; it was situated in the steam pipe at some distance from the steam slide valve, and worked with no other friction than what was due to its weight and snu~ fit. With this e~t-oft" no throtlle valve was used. The last cut-off is simply a sliding plate worked by the steam slide valve which draws the plate after it, thereby eutting off the admission of the steam into the cylinder at the very cylinder nozzles. This cut-off is fixed, and closes the steam port when the piston is 0.183 of its stroke from the commencement; a throttle valve controlled by the governor is used with it. The steam pipes leading from the boilers to the cylinders are well covered with felt and canvass, but the cylinders, their valve chests, and connecting pipe, are uncovered.