Our next type of wash-basin corresponds in principle with the valve water closet. The outlet is closed by a valve working in a small chamber or receiver, which, like the water closet receiver, is liable to become clogged with sediment. Moreover, the concealed machinery necessary to work the valve complicates the apparatus, and like all machinery, especially that which works under dirty water, is liable to get out of order. We have further subdivided this type into three kinds, i. e., those with (1) chain movement; (2) lever movement, and (3) gravity movement.
Figure 312 illustrates the first kind. We have here two elongated cesspools and a receiver cesspool. No overflow passage is shown in this drawing, though provision for overflow is of course as necessary as in any of the preceding examples.
A valve arranged as shown here would never work satisfactorily. The slightest impurity adhering to it or its seat would cause it to leak, and a little roughness or corrosion on the hinge might prevent its closing altogether.
Figure 313 represents a valve outlet basin operated by lever movement. The drawing shows a double bottom, the upper one being perforated throughout its entire extent, and forming an enormous strainer. The valve receiver occupies the whole space between the two basins. The amount of inaccessible fouling space is here very large and of peculiarly objectionable form, the many perforations and corners being calculated to retain a great deal of filth. The waste water escaping through so many holes would pass without force or scouring effect, and the cleansing of such a strainer would be practically an impossibility. Some overflow passage, not shown on the drawing, would be required.'
*Portable wash basin over fixed bath tub, from Joly, chapter headed "Appareils Economiques Perfectionnes." From the American point of view, the arrangement, especially the trapping", does not seem quite "perfect."
Fig. 312. Valve-Outlet Basin with Chain Movement.
Fig. 313. Valve-Outlet Basin with Lever Movement.
Fig. 314. Valve-Outlet, Basin with Outlet Supply.
Figure 314 shows a basin of the same kind with a smaller receiver. The supply enters below the strainer, which is evidently objectionable for several reasons. In case of fluctuation in the water supply pressure, foul water might be drawn from the basin into the supply pipes. Moreover, the dirty deposits in the valve receiver would always be mixed with the first clean water entering the basin.
Fig. 315. Valve-Outlet Basin with Improved Lever Movement
Figure 315 shows an improvement on the last device because the receiver above the valve is eliminated altogether.
Figures 316 and 317 give the third subdivision of our valve outlet basin, namely, that in which the valve is operated by the weight of the water falling upon it. Comment on such a device is scarcely necessary, it being sufficiently evident that its action would be extremely unreliable and unsatisfactory. The valve is made flat or cupped on its upper surface. In the latter case water held in the cavity of the valve is supposed to assist in forming a seal.
Figures 318 to 326 represent other forms of Valve Outlet Basin, all to be recommended for their simplicity, large outlets and cleanliness, there being no fouling chambers at the outlet. Where the overflow passages are accessible for cleansing, these fixtures are in all respects excellent.