334 WATER HYGIENE 
teria free. These authors further state that the action is selective in 
that certain harmless bacteria grow in this water. Table XXX will show 
some of the results secured by Hoover and Scott. Haller (1914) con- 
Back Pressure Gage 
Blow off Valve _ — ; 
Manometer Filling Screw SH | 
Glass Orifice. ff oe | ! 
Glass Orifice Cap — 
Manometer Scale 
Chloiine Control Valve 
Pressure Compensator 
Compensator Cap-———~___| 
Contact Spring —— 
Tank Pressure Gage 
Contact Arm——----—_" 
Pressure Equalizing Valve __ 
ee : 
a= 
ay 
S 
aman b . 
we 
at 
ann | as 
an ot 
ry tis to 3 
wig tt oe | 
2 ere — 
Pressure Pipe Valves 
Flexible Tank Connections 
Tank Valves 
Auxillary Tank Valves 
Valve Yokes 
Chlorine Lane 
se 
we ~ Check Valve 
7 Pa DiffusorTube ~ Silver 
“ , Open Conduit 
Diffusor 
{ Chlorine Tanks—~= 
Venturi Pressure Pipes 
Venturi Tube 
Hone es 
.2 20%} 
* 
Fic. 63.—Automatic Control Chlorinator, Direct Feed, Type B, Venturi Operated. 
(Wallace-Tiernan Co.) 
firms the statements of Hoover and Scott and also maintains that intes- 
tinal bacteria cannot live in a water from which the COz has been 
removed. He regards water which has been treated with calcium oxide 
safe for consumption very soon even though it was previously contam- 
