In fig. 46 are given a few curves showing the consumption of coal and of petroleum, and in Table XXVIII some useful data on specific gravity.

Fig 45a shows the system adopted by Mr. Urquhart for boilers of Lancashire or Cornish type, the essential brick chamber being fully present.

TH

Chapter XX

AMERICAN STATIONARY PRACTICE WITH LIQUID FUEL

"The Billow System,"

HE fuel oil appliances of the National Supply Company of Chicago consist of pumps and atomizers.

The first installation of fuel oil apparatus made by this Company was in 1886, since which time they claim to have furnished at least 80 per cent. of all the fuel oil equipment in the United States, to have sold more than twelve thousand oil burners to users, and to have designed, installed, and worked the fuel oil plant at the World's Columbian Exposition. This boiler plant consisted of fifty-five water tube boilers, of 25,000 h.p., and the fuel plant required twelve storage tanks, and 5-69 miles of pipe. The oil plant worked without one moment's interruption.

All atomizers are actuated in one or a combination of the following ways-by steam, by air supplied by an air compressor, or from a positive blast blower or fan. The various methods of combining the atomizing agent with the fuel constitute the distinguishing feature in their construction and economical operation.

If properly designed, the small particles are immediately and perfectly commingled with air and consumed. Therefore, an oil burner becomes more efficient and approaches nearer to perfection which will pulverize the greatest amount of oil with the least expenditure of energy.

An atomizer that will vaporize oil at the point of expansion of the agent used for that purpose, and is easily manipulated, properly designed and constructed, is the highest type that can be devised. The differences in construction and operation between the simplest jet burner and the most highly designed and efficient atomizer are solely these distinguishing features.

Atomizers are constructed with various shaped openings, through which the oil vapour is admitted to the furnace. They may be annular, flaring, slotted, semicircular or fan shaped, producing either a long, round, or a broad spreading flame.

Atomizers having annular openings are said to be more economical in steam or air than other forms, as a more intimate association of the oil and the vaporizing agent is afforded.

By actual experiment various atomizers consume from 3 to 15 per cent. of the entire product of the boiler in vaporizing sufficient oil to develop the capacity of the boiler. This feature, being quite essential, should be looked after with considerable care, as upon it much of the economy of a boiler depends.

The number of atomizers required for each boiler or furnace is directly proportionate to its size. Of atomizing agents steam is considered the best for boilers, air from a positive blast blower for furnaces where heat of medium intensity is required,

and air from a compressor for small furnaces. These are opinions not held universally as regards boiler furnaces.

The Billow Atomizer (fig. 47) is designed to cover the features above enumerated, with the object of vaporizing the greatest amount of oil with the least expenditure of energy, and is automatic in its operation within a 5 per cent. steam variation. It is of a form which it is claimed precludes the possibility of choking, clogging, dripping or the wasteful use of steam, air or oil, and is entirely constructed of brass of many forms and for either steam or air. The regulation and adjustment are good. In its design all the points necessary to produce the best results in oil

atomization are carefully observed. It is self contained. The fuel and the atomizing agent are controlled within the burner. It has ground joint union pipe connexions placed on an axis transverse to the body, a good feature, which permits the flame to be directed as desired. It is susceptible of a wide range in adjustment, and will perfectly vaporize a few drops of oil per minute or many gallons per hour. It is constructed with various shaped nozzles or outlets of the retort type, when desired, but these are not recommended on account of their wasteful steam or air consumption. Only in special instances should atomizers other than those with annular openings be employed.

Fuel Oil Pumping Systems,

In order to produce the highest results with fuel oil, a system for its handling and control between the storage tank and the atomizers is an important facto: This system must be so designed as properly to heat the oil, free it from mechanical impurities, and deliver it to the atomizer at a constant pressure and temperatur under the control of the operator. The amount of oil necessary for feeding the atomizers should be automatically controlled, and the system sufficiently flexible to pump the oil to one atomizer or any number within its capacity without useless expenditure. It should handle all grades of oil fuel equally well.

Residuum, or manufactured fuel oil, often contains particles of coke and sand. All grades may have dirt, bits of waste, sticks, floating and extraneous matter which disturb the adjustment of the atomizers at the furnace door, necessitating their frequent cleansing. These mechanical impurities also clog the feed lines, necessi tating their frequent blowing out. It is the duty of an oil pumping system to provide against the objectionable elements by filtering as well as removing these accumulations and cleansing the filtering medium without disturbing the continued performance of the pump.

These are essential features in the successful installation of a fuel oil equipment and the satisfactory action of the atomizer.

Feeding the oil at a temperature nearly approaching the point of distillation insures speedy vaporization, with a resultant flame soft and diffusing, and not sharply impinging upon the boiler surfaces. It is therefore essential, in order to obtain the highest economy, that the pumping system be designed so that the desired heat may be secured, and be also provided with the necessary automatic governing valves to insure uniform delivery to the atomizers under the desired pressure.

To meet this demand the National Supply Co. have designed a number of oil fuel systems covering all the requirements that have come to their notice in this direction. That these pumping systems are successful is attested by the fact that this Company alone has manufactured and placed upon the market almost four hundred complete machines.

These systems are considered indispensable in connexion with a modern fuel oil non-gravity equipment. They are compact, occupy a minimum floor space, and are so dripped and drained that no oil can reach the floor.

The National Supply Co. claim that any oil fuel produces the best results when heated to a temperature just under its distilling point, and that fuel oil is atomized with less energy when heated to such a temperature and delivered to a proper atomizer under a constant pressure.

That when air is used as an atomizing agent, carbonization is not liable to occur at the outlet of the burner in the furnace because the oil is passed through water heated with exhaust steam in the receiver, and minute quantities of water vapour are carried over with the oil, and this prevents carbonizing.

Double Pumping System.

These oil pumping systems (fig. 48) consist generally of a battery of two duplex steam pumps, specially brass fitted for oil, and of a cast-iron receiver, tested to two hundred pounds hydrostatic pressure, mounted on a cast iron drip pan and base frame upon which the mechanism is securely fastened. A partition divides the

T

receiver into two compartments or chambers. Projecting into the rear chamber and screwed to the partition are tubes with fine gauze heads, accessible through the rear head of the receiver. These heads act as a filtering or straining medium, and the compartment is provided with blow-off pipe and valve for removing any sediment of extraneous matter deposited therein.

The forward chamber is usually carried two-thirds full of water, and contains a coil of pipe through which live steam or exhaust steam from the operating pump flows. The coil has suitable controlling valves, permitting the use of steam from either of these sources or both at the same time.

One pump is held in reserve against contingencies or possible accident to the working parts of the other or working pump.

The apparatus is provided with a pump governor, or regulator, actuated by the pressure in the receiver to maintain a constant pressure on the oil in the receiver; a relief valve adjustable in construction and placed between the suction and the de

Fig. 48. DOUBLE PUMPING SYSTEM.

CAPACITY,

livery side of the pump through which all oil in excess of the requirements of the atomizer may pass in case of accident to the governor; a thermometer, steam, oil pressure, and automatically closing sight gauge. The apparatus is designed to pump and deliver any quantity of filtered oil within its capacity under uniform pressure and temperature. All joints are machine faced and metal packed.

In action the oil is discharged through the force chamber of the pumps into the forward chamber. The oil flowing through the hot water becomes heated and passes out through an inner tube to the point of consumption.

All sediment collecting on the tubes or in the rear compartment is blown out through a blow-off pipe without removing the cover.

These pumping systems are made up to sizes of ten to eighteen thousand boiler horse-power.

Thus No. 5 Double, employing two 51-in. by 31-in. by 5-in. duplex steam pumps has a capacity of five to fifteen thousand boiler horse-power, or twenty to forty gallons per minute.