Document b53EDovjo2LBGqbLzXDqjgB9Z

summer . POWERFAX 1 932 used entirely at all times and at other times the exhaust steam was not sufficient to meet the demand. In the first case, steam was ex hausted to the atmosphere, while in the second case steam was di rectly takenfrom theboilers. Steam at the main 450-lb. header had a B.t.u. value of 1350, the bled steam 1260 B.t.u. and the exhaust steam 1190 B.t.u. For costing purposes, the steam Oow to the turbine throttle, the bled steam, the total 25-lb. steam passing to process, and the 25-lb. steam taken from the main 450lb. header, were metered. The total cost of steam genera tion including fuel, labor, fixed charges, maintenance, water, chemical and sundry expenses was determined. This cost was pro rated to electric power and process steam on a heat basis. The difference between the total 25-lb. steam going to the main dis tribution lines and the 25-Ib. steam taken direct from the 450-lb. main steamheader gavethetotalamount of turbine exhaust steam used for process. An arbitrary figure of 10% of the steam generated was charged to steam generating costs since this ,w.as. used to operate accessories. To find the net steam to be used for calculations, the total steam as metered from both boilers, less 10%, was taken. The pounds of steam were then converted to a B.t.u. basis for determining the proration of heat units to elec tricity and process steam, .and the following calculations were made: 1. Total net B.t.u. available for process and electricity=steam metered at boilers--10% X1350 2. B.t.u. charged to electric power = steam metered' to turbine throttle X 1350 -- (total 25-lb. steam.metered to process -- 25lb. steam metered from main header) X1190 -- metered bled steam X1260 3. Per cent of net heat units charged to electricpower = Item 2 Item 1 4. Per cent of net heat units charged to process steam = Item 1--Item 2 Item 1 5. Total cost of steam generation 6. Total cost of electric power <=> Item 5 X Item 3 labor, main tenance, fixed charges, sundry supply, etc., charged direct to electric power 7. Total cost of process steam = Item 4 X Item 5. Since only a very small part of the process steam was used at 80lb. pressure, all process steam was charged at a. common rate on a pound basis. All process steam was metered before passing to the va rious departments. The first year operating cost summary showed a saving slightly better than the estimated saving. For the last three months of this period, the plant operated at a re duced production schedule, so that ifnormal operation had been main tained for the entire year, the ac tual saving would have been 25% higher than the original estimate. An analysis of steam and electric costs showed the saving in another way. The cost' of process steam in 1927 and 1928 averaged $0.35 per 1000 pounds and electric power $0,013 per kilowatt-hour. The av erage cost for the first year opera tion of the new plant Bhowed a process steam cost of $0.30 and electric power cost of $0,006 per kilowatt-hour; The actual saving the first year was $31,200.00 and if normal operation had been pos sible the saving would have been approximately $40,000.00. The entire installation met all expectations and the unit has op erated successfully after some pre liminary adjustments were made. Dependable NON-RETURN VALVES ElliottNon-Return Valves are sureoperating in emergency. Sudden back-flow of steam causes them to close positively and tighdy. Meanwhile, ia normal opera tion, their design permits the flow of steam from the boiler with the very minimum of pressure loss. Built for all pressures and tem peratures. Types of both singleand double-automatic valves for all purposes. Write for the bulle tin. ELLIOTT COMPANY Accessories Department Jeannette, Pa. m CRIMDEBN00000366