FIGS. 120-121.-Economy measuring apparatus.

FIG. 121.

In the view to the

Meters for individual units often prove helpful, as do particular sets of instruments for steam supply to the larger power units. left is shown the steam flow meter, carbon dioxide (CO2) indicator and draft gage installed on the front of each boiler unit. Note that the CO2 meter registers 14 per cent. and the draft 0.23 in. To the right is seen a steam flow meter, a draft gage and indicating carbon dioxide (CO2) meter on the boiler front and the Venturi meter for measuring the total feed water of eight boilers on a 20,000 kw. steam turbine at the Long Beach Plant of the Southern California Edison Company.

FIG. 120.

tight at all times, and any baffle tiles that have been disturbed by the replacing of tubes, gas explosions or from any other cause should be put back into proper condition before the boiler is fired up. The openings through the baffles for the passage of gases should be maintained the right area to suit the capacity required and the draft available.

14. Use Recording Instruments Wherever Practicable.Reliable records of the actual performances of a plant are of great aid to its efficient operation. By this means guess work is avoided and it can be determined accurately what method of operation or which man produces the greatest efficiency. To obtain efficient results means not only the installation of efficient machinery and recording apparatus but constant attention to operation.

Recording CO2 meters or an Orsat apparatus and draft gages are essential for efficient furnace operation, because they show excess air entering the furnace the greatest single avoidable loss in the combustion of fuel. Recording steam gages and flow meters are also of considerable assistance, the latter particularly because they show the quantity of steam generated by each boiler. A pyrometer or flue-gas thermometer should be used to measure the temperature of the exit gases. An additional steam-flow meter should be connected to the atomizing steam pipe and a record kept of the quantity of steam used by the burners. Thermometers and recording pressure gages on the steam and oil lines close to the burners also give valuable information.

15. Determine Efficiency Daily from Records.-The actual evaporation per pound of oil may be obtained by means of water meters and oil meters. The quantity of steam used by the burners may be obtained by means of a steam-flow meter in the steam-to-burner line. The greater the net evaporation per pound of oil, the higher is the efficiency of the boiler.

By keeping accurate records of the daily performances of boilers it is possible to compare one day's results with another. By trying different methods of operation, different furnace arrangements and different intensities of draft and comparing one with another, the best and most economical method of operating may be determined with certainty.

16. Fire Boilers Scientifically.-Boilers should be fired scientifically; that is, by basing the method of operation on the flue

gas analysis, temperature of escaping gases and results of tests and plant records. With careful attention paid to the draft readings and adjustments of dampers, this method will usually result in considerable saving. The recognition that trained engineers are rapidly receiving is most convincing testimony that the value of scientific management is becoming increasingly appreciated.

gage.

Co-operation with the employer and with other employees is absolutely necessary for successful operation of the plant. If the plant requires new equipment or repairs to old equipment in order to improve its economy, these improvements should be suggested to the employer, with an explanation of the resulting advantages.

CHAPTER XXIV

FUEL OIL BURNING APPLIANCES

In its course from the point of delivery at the plant to the burners the oil must pass through a number of appliances, which are necessary for the complete equipment of any oil burning plant. In this discussion we shall follow the oil in its journey through the plant and describe briefly the various appliances required for handling it.

FIG. 123. The cars are shown on the unloading track of the Redondo Steam Plant of the Southern California Edison Company and the oil is emptied from them into the flume which runs beside the tank; thence it goes into a small underground tank from which it is pumped into the main storage tank.

Oil may be delivered at the plant either by rail in tank cars, or by water in barges or tank steamers specially constructed for the purpose. From these it is pumped into large storage tanks, which may be of either concrete or steel. Storage Tanks.-For storage tanks are used.

power plants large cylindrical steel These are usually set on the ground

outside the plant, and are built in any desired size up to 50,000 bbl. capacity. They are built up of riveted steel plates, the thickness of plate and strength of riveted joint being proportioned in accordance with the usual safety rules based on the internal pressure due to the head of oil inside the tank. Thus if the tank is 30 ft. high the internal pressure will be that due to 30 ft. head of oil, or approximately 15 lb. per square inch. It is customary to surround the storage tank by a concrete wall about 10 ft. high far enough away from the tank so that the entire

FIG. 124.-Main oil storage tanks at Station C, Pacific Gas and Electric Company, Oakland, California. Tank in foreground is set low for fire protection purposes, while tank in rear is surrounded by concrete retaining walls. contents of the tank will be held in by the wall in case of a leak in the tank. This is to prevent the oil from leaking out to the surrounding country.

The size of storage tank required depends on two factors: 1. Quantity of oil to be burned.

This second factor depends on the location of plant, the method of delivery, and the probability of interruptions in delivery, all of which matters must be carefully considered in determining the number of days oil supply that should be carried at the plant. Most power plants are provided with tanks of sufficient size to enable them to keep from 10 to 30 days' supply of oil on hand.