. American engineer and railroad journal . volutions multiplied into the number of vanes, and it will beno disparagement to admit that the real cause was not under-stood for some years later when other experiments provedwhere the diffieultv lay. Since that time the writer has in all designs for water-raisingpumps of this class begau the volute at n, fig. 1. with one-fourth to one-sixth the area or section it has at the discia, thereby sacrificing a considerable portion of the tangentialenergy, and causing an accelerated flow in the casing. Thisnecessity for space in the discharge chamber at n,
. American engineer and railroad journal . volutions multiplied into the number of vanes, and it will beno disparagement to admit that the real cause was not under-stood for some years later when other experiments provedwhere the diffieultv lay. Since that time the writer has in all designs for water-raisingpumps of this class begau the volute at n, fig. 1. with one-fourth to one-sixth the area or section it has at the discia, thereby sacrificing a considerable portion of the tangentialenergy, and causing an accelerated flow in the casing. Thisnecessity for space in the discharge chamber at n, and thethroat or cut-off plate », is well understood. Messrs. London, have always arranged their pump chambers in thismanner. The cut-off or baffling plate 3 will be considered in afuture place. The nearness with which the vanes approach the volutechamber, or the radial depth at e, fig. 2. does not stem to be amatter of importance in a pumps operation, but regular -constructive matter of some importance — namely, whether the. Fig. 2. pump chamber has to be parted through its axis to insert theimpeller, or whether this be done through removable sideplates, as in figs. 1 and 2. In the latter case a pump chamber can be cast in one erected so the discharge will be at any angle, the sideplates, inlet and spindle bearings remaining undisturbed. Thismethod has been a characteristic of the practice of 51 -J. A II. Gwynne. above referred to. and is certainly desirablein nearly all cases, the exception being when there is no roomat the side to remove the impeller, and when the shaft mustpass through the pump, as in the case of circulating pumpsfor condensing water on board ships. Convenience and sym-metry favor the solid volute casing with removable side plates. THE VASE CHAMBER. The tapering form given to these chambers is an attempt tomaintain uniform area and consequent velocity of the water inits radial flow from the inlet. This is a rule of hydraulics, thevio
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
