June, 1925
'
IXDUSTRIAL 9.l-D E-VGI-YEERISG CHEMISTRY
Asbestos gaskets were riot affected by the same treatment and boilers equipped with these gaskets did not leak. Apparently, the tendency of the boiler water to foam has increased since the system has been installed. I n a broad sense, there has been no foaming of the boilers as this term is generally used. Foaming, however, is a relative term and the phenomenon may take place without violent ebullition of the water. The presence of soda deposits in the steam traps about the plant is proof that water containing soda has been carried into the system. Cost of Operation The plant as installed cost $13,000, including erection charges. Based on this capital charge, the annual operation of the system during 1924 was $3278. Details of the annual fixed and operating charges under normal load are as follows :
585
Operating labor Maintenance Water used in back-washing Salt Interest, taxes, and depreciation
TOTAL
$803.00 100.00 230.00 585.00
1560.00
$3278.00
The total quantity of water softened was 81,470,000 gallons. The cost of softening water per lo00 gallons was 4 cents. It is difficult to determine accurately the net labor and fuel saving that has been effected by the system. Since the treating plant was installed waste heat boilers have been put into operation, thereby introducing a factor not comparable with conditions prior to the use of softened water. No comparison of fuel consumed is possible, as the character of fuel varies with the percentage of bituminous coal and coke breeze employed. The writers are convinced, however, that the use of completely softened water under local conditions has resulted in a great reduction in boiler maintenance and operating labor, as well as in fuel.
A Useful Laboratory Pump' By D. H. Cameron STATE UhTVBRSITY OF
REQUENTLY in the laboratory it is necessary to circulate water of constant temperature through jacketed apparatus such as polariscope tubes and refractometers, or to circulate ice water through a condenser or in other ways handle liquids with a pump. The pump described below has been found useful, and because of its simplicity it can be constructed from material found in every laboratory. The pump circulates the original liquid without dilution or addition of tap water. Both the construction and operation of the pump are apparent from the diagram. It is operated by the suction produced by an ordinary water vacuum pump. It has a flow of 1 liter per minute and will readily elevate water through a vertical distance of 1.8 meters (6 feet). The liquid flows by gravity from the constant temperature bath, through the jacketed apparatus, to the beaker containing the inlet valve of the pump. From that point it is elevated and returned to the constant temperature bath by the pump. The pump chamber is a glass cylinder of 45 mm. internal diameter and 26 cm. in length. This is equipped with two solid rubber stoppers cut and fitted as indicated. The upper one is cut to receive a U-tube of 12 mm. internal diameter and a tube to connect to the suction. The lower stopper is converted into a check valveZ by cutting a 5-mm. layer of the stopper almost off and then cutting through the center of the stopper with a large cork-borer, care being taken not to cut into the hinged flap first made. A short length of glass tubing is fitted into the hole last made, to prevent the stopper from collapsing and sliding too far into the tube when the valve is put in place. The inlet valve is a short-stemmed powder funnel, 6 cm. in diameter with a stem of 12mm. internal diameter. This is attached to a 15-cm. length of soft rubber tubing, which is connected to the U-tube of the pump by a vertical tube of 12 mm. internal diameter. The flexible soft rubber tube carrying the inlet funnel is held in a clamp at an angle as indicated, so that the funnel, with paraffined cork float, can swing up and down in the beaker as the liquid level in it rises and falls. It is essential that the tube connecting the inlet valve to the pump chamber be in a vertical position 1
Received October 1, 1924. 16, 32 (1923).
' Rrewster, THISJOURNAL,
IOWA, IOWACITY, I A
so that water may drain from the tube quickly and allow free entrance of air through the tube during the period when liquid is discharging from the pump chamber. The rate of flow of liquid when flowing by gravity through the system is controlled by a screw clamp or valve and is kept below the maximum capacity of the pump. This gravity flow discharges into the beaker containing the inlet valve of the pump. When the liquid in the beaker reaches the level A , air is no longer free to pass into the pump through the inlet, and since the air suction applied to the pump is continuous, water from the beaker is elevated into the pump cylinder. As liquid is drawn into the inlet funnel it sinks to the position B and remains in that position till the liquid level has fallen below the upper edge of the funnel. When this occurs the suction is broken, the funnel floats upward to the original position, air is free to enter the pump, and the check valve in the bottom of the pump chamber opens, permitting the liquid to discharge by gravity. When setting up one of these pumps a little experience will a u i c k l v teach one t^he adjistments that will " give the best results. It is suggested that the flow of water to the beaker be so regulated that, during each cycle of operation, the pump chamber is filled not more than two-thirds full and is completely drained. Too rapid a flow to the inlet beaker will cause the pump to take more than it can discharge in the cycle and some of the liquid will be lost through the suction line.
