Fig. 36 shows a specially designed pumping system for sup plying fuel oil in uniform quantity and at even pressure. It consists of a duplex pump and receiver mounted on a cast-iron drip pan supported at a convenient height on cast-iron legs. The pump takes the oil directly from the storage tanks and at set pressure automatically forces it through the receiver to the burners, through suitable pipe lines, the machine serving one or any number of burners within its capacity with equal uniformity. The receiver contains a coil of pipe, which can be connected with the exhaust of the pump, heating the oil, if necessary, through a medium of water. A special governor is furnished which auto matically stops and starts the pump as the pressure in the receiver rises and falls. The receiver is specially equipped with the glass gauge, pressure gauge, thermometer, etc. This pumping system is constructed both of single and double type. In the double type one pump is operated at a time, and the other is held in reserve in case of breakdown. Fig. 37 shows another type of pumping system.
A pulsometer should be installed in the line between pump and furnace so as to prevent variation of pressure due to piston action. For a 3" feed line, a 15" pipe 5' long with a provision at the bottom for the removing of sediment will be found bene ficial. Fig. 38 shows a puisometer.
Mr. C. D. Stewart writing in Oil Newsa states as follows: "On the Pacific Coast where oil burning was first practiced to any large degree automatic apparatus has been devised and de veloped since the use of fuel oil began, and today most of the plants in that territory are equipped with mechanical oil stokers. Automatic systems are firing boilers at high efficiency in plants of nearly every character, including power stations, sugar re fineries, canneries, spinning mills, smelters, ferry boats, river boats, etc. It may be of interest to describe a stoking system operating on the step principles and providing for the accurate control of the three (3) elements of combustion in every step.
Atomizing steam, fuel oil and drafts are changed in each step of the fire in proportions that give the highest possible CO, throughout the entire range. Line drawings, as shown, illustrate the apparatus as applied to these installations.
Fig. 39 is a diagrammatic view of the burner regulator, one of which is applied to each burner.
Fig. 40 is a diagrammatic view of the Master Controller Set, controlling the entire plant, whether one or fifty boilers.
Fig. 41 is a cross sectional view of the Interlocking Damper Device, the number per plant varying according to the work to be done.
Briefly, the operation of this apparatus is as follows : Boiler steam pressure present at all times above the dia phragms of the Master Controller Set causes it to function so as to step up the fires in case of a drop in steam pressure and to step clown the fires in case of a rise in steam pressure. Fuel oil, which is under pressure to the burners, is also used as the actu ating medium to perform the work of opening and _closing the oil and steam valves to the burners and closing the dampers. Weights, as a safety measure, are used to open the dampers. The Master Controller Set, acting under the influence of boiler steam pressure, admits fuel oil pressure to the interlocking damper devices to close the dampers and releases it from the damper devices to permit the opening of the dampers by the weights. The Interlocking Dairper Device was so named because of 'its construction, which is an application of the principle used in railway switch and interlocking plants. In the performance of its functions a step up in the fire cannot be brought about until the dampers are open an amount that will give correct com bustion for that step of the fire, and a step down in the fire is made before the dampers close an amount to give the correct combustion for a lower fire.
The individual burner regulator, as illustrated and described in this article, provides for a three (3) stage fire on each burner, however, more or fewer steps can be provided where conditions make it desirable. The regulator consists of three main portions: One portion comprises fuel oil and atomizing steam orifice valves, which regulate the amount of fuel and atomizing steam that flows to each burner in each stage of the fire. Another portion com prises plunger valves which govern two stages of the fire. A third portion comprises actuating pistons which open and close the plunger valves. The three stages of the fire are known as pilot, medium and maximum fires. The pilot fire is not auto matic and, therefore, not governed by a plunger valve. The size of this fire is determined by the opening of the pilot orifice valves which consists of 'one oil and one steam valve. The medium fire orifice valves govern the size of the fire in the second stage, hut no flow takes place by these orifice valves until the medium plunger valve is unseated. The maximum fire orifice valves do the same for the maximum fire and the maximum fire plunger valve starts and stops the flow by the orifice valves. When the installation is completed, each step of the fire is set according to the needs of the plant and the drafts adjusted to give the maximum efficiency in each stage, and with the fluctuation in steam pressure, the apparatus will function day after day without variation in efficiency. The Master Controller Set is designed to maintain steam pressure within 3 lbs. of the maximum at all times. The Master Controller, as illustrated, comprises two (2) portions,•but in a number of large power plants, the Master Con troller Set comprises four (4) portions and the plant so piped that a group of boilers sufficient to carry the normal load 'of the plant is on one portion of the Master Controller and these boilers are fired at their maximum rating. Other boilers are connected in series with the Master which functions only in case an ab normal load develops and these boilers are used only for the peak load. In this way still higher efficiency is realized by keeping a certain group of boilers operating normally at their designed capacity. There are a number of applications to this principle which have been made on the Pacific Coast due to the flexibility of the unit principle. Still another refinement that is interesting has been worked out in one or two large power plants which are used as standby plants to pick up the electric load in case of an interruption on the hydro lines. When this interruption comes, it is necessary to have the steam plant on the line in the shortest possible time, as every second counts. Accordingly the Master Controller Set, instead of being connected to the steam pressure at the boiler, is tapped into the steam mains at the turbine, with the result that the instant the load comes on the turbines, the Master Controller fcels.the steam drop instantly and has the fires under the boilers before the steam gauges have recorded any variation. As a result, one of these plants has gone from zero to maximum load instantly with a maximum drop in steam pres sure of only six pounds." . Fig. 42 shows a fuel oil pump set controlled by a spring control diaphragm regulator.
Fig. 43 shows a fuel oil pumping, heating and regulating system for power boilers.