Fire pump

“ The modern high buildings make such apparatus useless at the present time.
The numerous hand pumps would not receive notice here, were it not for the fact that one of them has been incorporated into a regular fire department. The Johnson pump, made by the National Manufacturing Company of Boston, is composed of a vertical cylinder and piston, provided with an air chamber. A short piece of hose that can be held in the hand is attached near the top. The pump is placed in a pail of water, and an adjustable clamp enables the operator to steady both pail and pump. ”

“ The pressure in a quick-moving fire-pump necessarily fluctuates 5 to 15 pounds at different points in stroke, and an air chamber of reasonable size cannot wholly remove this. Therefore the safety valve must be set at about 15 pounds higher than the intended average working pressure; otherwise it will get to jumping with almost every stroke. ”

“ It is recognized that the practice of making adjustable valve tappets located outside of the steam chest is a good thing in a large pump in constant service and operated by a skilled engineer, but for the infrequently used ordinary fire-pump, the utmost simplicity is desirable, and it is best not to tempt the ordinary man to readjust the valve gear. ”

“ Owing to the very high speed at which these pumps are liable to be run during a fire, all the working parts are made excessively strong, and the valve area and water passages are larger than usual. The interior of each Underwriter pump is treated with a rust-proof coating, and every precaution taken so that the pump will start instantly after an indefinite period of disuse. ”

“ The development of fire-fighting machines cannot be claimed exclusively by recent generations. As early as the reign of the Ptolemies in Egypt, some 200 years before the Christian era, a hand-pump fire engine was constructed which was similar to those later used in the 19th Century. This first known fire engine was described by the Greek writer Heron, who reported that the machine operated through a pump and air-chamber mechanism which forced water out of a spout by means of compressed air. ”

“ Fig. 161 represents a double acting force pump used extensively on ship-board, wharves, around factories, mills, etc., and in residences, for tank pumping. On ships these pumps perform the three-fold purpose of filling boilers when cold, washing down decks and to satisfy government inspection as to fire protection; in service in mines they are unaffected by mine water, the working parts being made non-corrosive. It is claimed that a three-inch diameter cylinder with a stroke of four and a half inches with a 11⁄4-inch suction pipe and 1-inch discharge pipe will lift and force water 150 ft. ”

“ The main feed pump is, even in the independent type, often placed in the engine room, while the auxiliary pump, or the injector, is in the fire room. The feed pumps draw usually from the hot well, feed heater and feed tanks and discharge through main feed pipe into the boiler.
162
This “doctor” pump is a substantial piece of mechanism. The bases of columns and pump chamber flanges are accurately planed, the cylinder has spring piston packing and the plain slide valve is made of gun metal. ”

“ As the loading of fire-pumps is somewhat difficult, it will be necessary to make two or three trials before you depend on their performance. When you fill a number of pumps, take care not to put in each an equal quantity of [Pg 187] charge between the stars, so that when they are fired they may not throw up too many stars together. Cases for fire-pumps should be made very strong, and rolled on 4 or 8-ounce formers, 10 or 12 inches long each. ”

“ Fuel oil is supplied to the spray nozzles by a governor controlled pump having a variable stroke or by compressed air as in the Diesel engine, making the supply of fire proportional to the load. A separate pump is generally supplied for each cylinder, which is capable of developing a pressure of about 400 pounds per square inch. Several of the Semi-Diesel type engines have water sprayed into the cylinder for the purpose of cooling the cylinder and piston, and as an aid in the combustion. ”

“ It is all right to run fire-pumps at the highest speed that is possible without causing violent jar, or hammering within the354 cylinders. Considerations of wear do not affect the brief periods of fire services or test, hence these speeds are greater than those allowable for constant daily duty. ”

“ Large rotary pumps for dredging purposes with their engine equipment for salt water service, include surface condenser outfits with air pumps, feed pumps, fire pumps, etc. The dredges for fresh water are very large cross-compound engines, double-acting air pumps and jet condensers with the usual complement of vertical duplex feed pumps, fire pumps, etc. The air pumps are of a very novel arrangement, inasmuch as it is possible by the manipulation of valves and cocks provided for the purpose to separate the pumps and run one side entirely independent of the other side. ”

“ Cases for fire-pumps are made like those for tourbillons; only they are pasted instead of being rolled dry. Having rolled and dried your cases fill them: first put in a little meal-powder and then a star, on which ram, lightly, a ladle or two of composition, then a little meal-powder, and on that a star; then again composition, and so on till you have filled the case. Stars for fire-pumps should not be round, but must be made either square, or flat and circular with a hole through the middle: the quantity of powder for throwing the stars must increase as you come near the top of the case ”

“ Often, especially with large pumps, “4 to 1” construction is a mistake, and gives no additional security, although the pump might start and give a few puffs with 30 lbs. of steam on banked fires; because, if any pump of whatever cylinder ratio draws 50 or 100 horse-power of steam from boilers with dead fires, it can run effectively only a very short time (ordinarily, perhaps, 3 to 5 minutes) , unless fires are first aroused to make fresh steam to replace that withdrawn. ”

“ In such a case it would be possible to use very powerful pumps, as an electric motor is extremely vigorous for its size and weight. Even to-day steam fire engines can fling 2,000 gallons per minute, and fire floats (for use on the water) considerably more. Possibly the engine of to-morrow will pour 5,000 gallons a minute on the flames if it can get that amount from the water mains, and so render it unnecessary to summon in a large number of engines to quell a big conflagration. Three hundred thousand gallons an hour ought to check a very considerable "blaze." ”

“ There is no liability to boiler explosion, or trouble from impurities deposited by water in a boiler. There is no exposed flame or fuel-bed requiring attention. The mechanism of the motor is simple, and its moving parts are few. A gas or oil engine furthermore enjoys a combustion which is smokeless. The fuel requires no diluting excess of air, with its cooling effect and incidental waste of energy. Dust, sparks and ashes are avoided, with diminished risk of fire. Liquid or gaseous fuel can be served by pumps or blowers so that the cost of handling is avoided. ”

“ The earliest aerial ladders were made of wood and mounted on horse-drawn trucks, with ladders being raised or lowered by hand-operated cranks. Today’s aerial ladder truck, as shown above, embodies tremendous improvements in safety and efficiency.
The modern pumper pictured above has an output of 1,500 gallons of water per minute, more than four times the pumping capacity of the Carillon Park steam fire engine. In addition, it carries 1,600 feet of hose.
A 275-horsepower motor provides instant and dependable power. ”

“ At one end of a beam stands the retort or furnace with the motor cylinder, and at the other end stand three pumps. One of these forces air into the furnace, a second supplies the receiver of the fog signal, while the third, which is smaller than the second, performs the same office, when it is desired to raise the pressure to a point too high for the larger pump to accomplish. ”

“ The water pressure will vary only as the steam pressure varies, always keeping the same per cent. of excess. The results are directly opposite to what would or does occur where feed water is delivered at a stated pressure. On a battery of boilers, during the cleaning of fires, the closing of feed valves on one, two or more boilers, does not affect the feed of those already set in the least, the pump will simply make less strokes necessary to properly feed the others. ”

“ The high-class turbine pumps of to-day are simply machines in which the water is given a velocity which is partially changed to pressure before discharge, and the pump is designed so that the well-known actions, outlined above, proceed along natural lines, which are, to use the common phrase, lines of least resistance. It is simply a question of careful design.
The modern pump causes the water to flow along paths naturally due to the forces acting and to guide the stream in such a way as to avoid the production of eddies and whirls within itself which so enormously cut down the efficiency. ”

“ When it becomes necessary to pump water, there are numerous machines from which to choose; only the more important ones will be considered. We may use pumps operated by manual labor, those run by ani [Pg 40] mal power, pumping machinery using the power of the wind or that of falling or running water; then there are hot-air, steam, and electric pumps, besides several forms of internal-combustion engines, such as gas, gasoline, and oil engines. Each has advantages in certain locations and under certain conditions. ”

“ If the gas is turned off, the fires in houses and factories would go out, and if it were turned on again without notice, the rooms would be full of gas, and an explosion follow an attempt to relight it. This danger is now being removed by the invention of an automatic valve in the pipe supplying each fire, which will close and lock when the flow of gas ceases, and admit no more gas until it is opened. The ordinary pressure for house service is about two pounds to the square inch. ”

“ The big, electric motor spun into action and settled into a workmanlike hum. The overhead light dimmed briefly when the pump load was thrown on and then the slip-slap sound of the pump filled the shed. They watched and listened for a couple of minutes. Assured that the pump was working satisfactorily, they left the wrecked pumphouse.
Johnny was carrying the gasoline can of milk. "Good thing you set this off to one side where it didn't get hit and go off," he said. "The way this stuff reacts, we'd be without a pump, engine, or windmill if it had. ”

“ Iron ignition tubes may be used, and one heating lamp serves a double purpose in keeping the tube and vapouriser hot at the same time. This lamp is fed by means of a pump actuated from the side shaft. The plunger of the pump is loaded with a spiral spring, which may be adjusted to give any desired pressure, and is kept constant and steady by means of an air vessel. This pump is shown in fig. 48. It is actuated by means of a rod and lever from the side shaft of engine. ”

“ These vanes form tangential, expanding ducts from which the fluid emerges at about the velocity existing in the chamber. They also eliminate all drag and friction between the periphery of the rapidly revolving impeller and the slowly moving water in the discharge chamber.
The turbine pump has created an entirely new field of application for centrifugal pumps, embracing mine drainage, water-works, and numerous other services where rotary pumps are desirable but have not been employed, owing to their former limited efficiency at high heads. ”

“ A vacuum pump is an apparatus consisting of, 1, a chamber or barrel; 2, a suction pipe with a valve to prevent return flow; 3, a discharge pipe which has a valve which is closed when the chamber is emptied and, 4, a steam induction pipe provided with a valve that is opened when the chamber is filled with water and closed when the chamber is filled with steam.
It is not right to call an air pump a vacuum pump, as the latter does not move air alone; it removes water, vapor and air from the condenser to form a vacuum. An air pump is designed to pump air alone. ”

“ For promoting the combustion of fuel the draft is energized by blasts of air or steam, or both, either through hollow grate bars, jet pipes in the fire box, or by discharging the exhaust steam in the smoke pipe. Surface condensers pass the exhaust steam over the great surface area of a multitubular construction having cold water flowing through it. Feed water heaters utilize the waste heat escaping in the smoke flue to heat the water that is being fed to the boiler, so that it is warm when it is [109] injected into the boiler, and the furnace is relieved of that much work. ”

“ In using a fuel engine it is desirable, because of the attendance required, to take a machine of such capacity and size that the water supply required for two or three days may be pumped to the storage tank in a few hours.
Expansive Force of Heated Air Utilized
A favorite and extensively used type of domestic pump is the hot-air engine, in which the expansive force of heated air is used to do useful work. Among the types are simple and safe machines which do not easily get out of order. They are started by hand by giving the fly wheel one or more revolutions. ”