Document 4E5nO36bn13k80xQqyn1YkaN

Ventilators American-Larson Ventilating Co. 324 Fourth Ave., PITTSBURGH, PA. Product: American-Larson Ro tary Suction Ventilators--proven, by competitive tests, to be the most efficient ven tilator on the market. Efficiency: In a recent (Jan uary, 1923) test conducted by a disinterested party, more than 50 makes of ventilators were tested over a wide range of wind velocities and temperature differences with the result that the American-Larson Ventilator was shown to have the highest rating. Here are the reasons: The American-Larson Ventilator offers less re sistance to the passage of air than any other ven tilator. be it of the stationary or of the rotary type. The patented ejector tube effects air movement in direct ratio to wind velocities and temperature differences. Most ventilators do not function at all in wind only (no temperature difference) velocities below 3K miles per hour; furthermore, under tem perature differences as great as 30 deg. fahr., the efficiency of these ventilators actually decreases in gentle breeze up to 4 or 5 miles per hour velocity. EFFICIENCY TEST OF A 16* AMERICAN-LARSON SUCTION VENTILATOR Htw-xtra* ac Further proof of the efficiency of AmericanLarson Ventilators is furnished by a comparative test conducted by Professor Trinks of the Carnegie Institute of Technology of Pittsburgh, in 1921. The results are shown below: X TM 18" Stationary Siphon Ventilator. V ^ 18" Rotary Siphon Ventilator. Z-JS" American-Larson Suction Ventilator. The official report of the Institute says, in part"The comparison shows that the American: Larson is far superior to both types at all wind velocities. At very low velocities of wind, it still ventilates while the other types do not move any air. Simi larly. the American-Larson Ventilator utilizes wind to increase the effect of temperature differences, while in the other types a gentle breeze actually dimin ished the ventilating effect." Number and Size of Ventilators Required The air supply per person and per hour,, or the number of reversals of air contents per hour may be taken from the following table: Type of Room to be Ventilated Schools.............................................. Number of Renewals of Air Contents per Hour 2 to 3 4 5 to 8 5 to 8 Restaurants....................................... 5to 10 8 to 12 8 to 12 10 to 12 IS to 20 lOto 12 5 to 6 To obtain effective, uniform ventilation and avoid local drafts, ventilators should be placed not more than 30 ft. apart; 20 ft. is a good average. It is best to locate them at the ridge unless the building exceeds 40 ft. in width, when two rows of smaller ventilators may be used. Where the build ing is surrounded by higher buildings, it is desirable to extend ventilators above them by mounting on stacks. Example Showing Method of Calculation-- In a building 100 ft. long. 35 ft. wide and 28 ft. average height the air is to be renewed 5 times per hour. How many and what size ventilators are required? With a spacing of ventilators 20 ft. apart and 10 ft. from the ends, in one row along the ridge, 5 ventilators'are required. (100 x 35 x 28 ft.) X5 changes hr. ^ cu 5 ventilators per hour to be exhausted by each ventilator. From the table of capacities of American-Larson ven tilators under average wind and temperature con ditions. the nearest size is 24-in. size. Requirements: Five 24-in. ventilators. . For specified conditions of height, temperature and wind, the capacity of the American-Larson ventilator is: 0=/i [3CV'"+y~<0) +20xr] where Q is cu. ft. of air exhausted per hour, through a ventilator having the throat area of A sq. in., mounted on a roof at a height of H ft. from the center of the ventilator outlet to the floor, and with a wind velocity of V miles per hour, and average temperatures tl inside, and t outside the building. The above is based on sufficient area of openings in the sides of the building for inlet of fresh air. American-Larson Ventilating Co. Ventilators Suggested Form of Specification Note t: (1) All ventilators shall be American-Larson Suction Ventilators, as manufactured by the Americlan-Larson Ventilating Company, of Pittsburgh. Pa., and shall [shall notl be equipped with dampers. (2) The ventilators shall be made of {see Note l) and shall be of the following gauges: Below 18-in. diam.. No. 24 gauge; 20 to 24-in. diam.. No. 22 gauge; 30 to 48-in. diam.. No. 20 gauge; 54-ih. diam., No. 18 gauge. (3) Where so indicated the ventilators shall be mounted on extension piping of sufficient height to raise ventilators above surrounding obstruction. (4) The ventilators shall be erected plumb and in a substantial manner. Where extension pipes are used- they shall be anchored to four points with heavy gauge guy wires. (5) Ventilators for ` shall be equipped with fus ible links toclosedampersautomatically in case of fire. Material of Ventilator Size (throat diam.). in. Dimensions, Gauges. Weights, Prices and Capacities B in. C in. D in. E in. Iron gauge No. List price. damper List price. ventilators only Net weight, lb. Crate< weight lb. Average conservative discharge 5 miles velocity 8 27 10 10 10 24 $1.50 $20.00 10 34 13 12 12 24 2.15 20.00 12 41 16 13 13 ` 24 2.90 30.00 14 48 18 17 1/ 24 3.30 35.00 16 55 21 20 20 24 3.80 40.00 18 62 24 21 21 24 4.30 45.00 20 69 26 25 25 22 4.80 50.00 24 83 32 30 30 22 5.80 60.00 30 104 40 38 38 20 7.15 75.00 36 125 48 46 46 20 9.30 110.00 40 139 53 51 51 20 11.50 140.00 48 167 64 61 61 20 17.00 170.00 54 187 72 63 63 18 20.00 220.00 60 208 80 76 76 18 25.00 300.00 66 229 88 | 84 84 18 35.00 1 375.00 12 26 11,550 18 26 32 35 46 57 17.820 24,800 34,960 39 70 46,200 a 49 85 58,410 a 68 115 71,940 a 92 145 103,620 a 146 206 161,700 a 225 325 232,890 a 282 412 287,760 a 390 560 412,500 . a 620 820 524,700 a 790 1025 646,800 a 930 1215 782,100 Prices (object tojehange without notice. Discounts furnished on request. Uses of Ventilator 1. All purposes for which no acid or corrosive fumes pass; sUndard practice. 2. AH purposes for which l*ng life ts desired, provided that no strong ada or fumes pass. 3. For ventilating or rooms ' from which acid or other corrosive fumes rise. 4. Same as No. 3: has longer life, but is more expensive. 5. Similar to copper, but a little cheaper. Vane firmly riveted to top I Vane reinforcement rods heav- ________ ily galvanized ISpindle attached to reinforcing ____________ plate______ (Heavy standing seams adding] I strength and rigidity IStee) center spiitdle coated] 1 with rust resisting paint Stabilizing rings on both top and base give concentric ac tion. making top and rod pivot as one Dustproof and rustproof ball bearing of best quality insures free pivot action and is noiseless. Used as a steady bearing Suspension spider is weather protected ana Holds step bearmg rigid _______ jGraphite step bearing needs no| | lubrication or attention Vane keeps ejector presented to outside air currents, pre vents bock-draft and makes ventilator stormproof and dustproof Unrestricted area permitting easy discharge minim. fric*n Mouth weather protected offering unrestricted area for exhaust Ejector tube an exclusive patented feature. The air cur rents passing,through create a suction that makes this the most efficient ventilator Direction of outside air current] through the ejector Axis of ejector in line with ex-1 haust which is always upward)' Counterweight which gives]" ventilator perfect baling ] Line of exhaust upwards of fering low resistance to upward draft Easily routing design of spindle and ball bearing and made of best materials IDesign of working parts in.] I creases maximum effirienry { I Noiseless pivoting--is fooL| |proof and requires no attention AMERICAN-LARSON SUCTION VENTILATOR (Patented) 5939 S.E.--2/2--17.5 505