Document OJaxeeOMyvzoxJJnVqk2MxXGp

CARE OF STEAM BOILERS Cleaning Steam Boilers The steam boiler should be cleaned within one week after it is installed and in operation. This should be done to remove any accumulation of oil, grease, etc., which has a tendency to cause the boiler, to foam, producing a very unsteady water line. It is thus necessary to blow, off the boiler under pressure. If one blowing-off does not result in a steady water line and clear gauge-glass, the operation must be repeated a second and if necessary a third or fourth time. Gose all radiator valves, or, if the mains are equipped with valves, close both flow and return valves tightly. * ' - Fill the boiler to.the top of the gauge with water. Build a hot fire in the boiler and get up a pressure of 10 to 15 lb. Open the blow-off cock and be careful that sufficient fire is carried to maintain a pressure until the boiler is empty. After doing this, draw the remaining fire and allow the boiler to cool down thoroughly. This will require one-half to one hour's time, after which close the blow-off cock and slowly fill boiler to water line. Open all radiator valves or valves on flow and return mains and rebuild fire, and the heating plant is ready for operation. How To Clean a Water-Gauge Glass on a Steam Boiler Without Removing It '' y 1. Draw a cupful of hot water from the boiler, into which pour at least a table spoon of raw muriatic or other acid. 2. Close both water-gauge valves. 3. Open top water-gauge valve and also pet cock at bottom, and blow water out of glass. Then immediately close the top valve and submerge the end of the pet cock in cup of hot-water solution. A vacuum is at once created in the gauge glass which causes the solution in the cup to rush in. -- 4. Keep the pet cock immersed and operate the top valve, slightly opening and closing, alternately expelling and drawing in the solution until all grease, oil, or other matter adhering to the inside of the glass is cut out. Then close pet cock and open both water-gauge valves. It is necessary to have 1 lb. pressure of steam or more on the boiler before com-' mencing this operation, which need not occupy more than 10 minutes. The result is a clean glass without the risk of breakage and probable renewal of gaskets, which is frequently the case when removing the glass for cleaning. 148 PIPE SIZES FOR GRAVITY HOT WATER HEATING (From Mechanical Equipment of Federal Buildings, By Nelson S. Thompson) Two-Pipe Hot-Water Basement Mains, Gravity Circulation, Direct Radiator Tappings First Floor 40 70 110 180 300 Second Floor 50 80 120 195 350 Third Floor 60 90 135 210 400 Fourth Floor 70 100 150 230 500 Pipe Size Inches A 1 VA IA 2 At ends of mains increase tapping one size. No main to be less than l'l in. To get size of mains and risers serving more than one radiator, add area of tappings together and use the following: Inches l/i equals 2 equals 5 1 equals 10 equals 20 1/12 equals 30 2 equals 60 2J4 equals 110 Equalizing Table Inches 3 equals 175 3J4 equals 260 4 equals 380 5 equals 650 6 equals 1,050 7 equals 1,600 8 equals 2,250 To get size pipe to serve a -kt-inch pipe and a 1-inch pipe: in. equals 5 1 in. equals 10 15 equals 1% in. Expansion-tanks are made 1 gal. to 30 sq. ft. radiation up to 1,000 sq. ft.;1 gal. to 40 sq. ft. 1,000 to 2,000 sq. ft.; 1 gal. to 50 sq. ft. 2,000 to 5;000 sq. ft., and 1 gal. to 60 sq. ft. for jobs above 5,000 sq ft. in radiators. THE FRICTION OF WATER IN IRON PIPES AND ELBOWS By F. E. Giesecke Data and experiments carried out by the Division of Engineering, Bureau of Economic Geology and Technology of the University of Texas, led to the establishment of the formula h = 0.00685 -v--177 d 1275 showing the relation between the friction of flow of water (h) and the velocity (v) for clean iron pipes ranging in size from ^ to 3 in. when the water has a temperature of about 68 deg. fahr. and flows at velocities up to 3 ft. per sec. The friction of water at temperature of about 68 deg. fahr. in. one standard short-radius steam elbow is given by t)186 h = 0.0141 d <>*. (For the complete paper see Transactions A. S. H. V. E., Vol. XXIII, 1917, p. 499.) 149