Steam pump

“ Power pumps can be used only where the character of the sewage will not clog the valves nor corrode the pump. A direct-acting steam pump is one in which the steam and water cylinders are in the same straight line and the steam is used at full boiler pressure throughout the full length of the stroke. The crank-and-fly-wheel type of pumping engine permits the use of steam expansively during a part of the stroke, the energy stored in the flywheel carrying the machine through the remainder of the stroke. Reciprocating pumps are sometimes classified as plunger pumps and piston pumps. ”

“ The rotary pump is used also in places where a piston or steam pump would be objectionable either on account of floor space occupied or for the reason that steam could not be had without too much expense for lifting and forcing water and other liquids which would not nor could not find their way through the tortuous and narrow passages of the average piston and plunger pumps. ”

“ Still another recent form of steam pumping-engine, noted for its cheapness combined with efficiency, is that of Worthington (Fig. 22) , in which two pairs of steam cylinders, A, B, are placed side by side, each pair driving a pump-plunger, F, attached to its piston-rod, and each having its valve-gear, H L, M N, actuated by the movement of the piston of the other. The cylinders together form a compound engine; the steam exhausted from the smaller, A, passing into the
Tomb of James Watt, Handsworth Church, 1819. ”

“ A still greater use of expansion may be obtained by the introduction of a condenser which allows the final exhaust to be carried below the atmospheric pressure to the extent of the vacuum formed. In stationary and marine practice triple and quadruple expansion engines are common. These are used in large units to give the greatest possible economy in fuel.
Properties of Steam.—Before taking up in detail the valve and other mechanism of the steam pump it may not be out of place to consider briefly the action of steam and its expansive properties. ”

“ Its low cost, as it does not require an engine or other machinery to operate it. A steam pipe connecting it with the boiler that is to furnish steam supply is all that is necessary, and after the pump is once adjusted, it will always be in order with free power when the steam is turned on. 2. It is absolutely noiseless in its operation; the slight click of the steam ball-valve in the neck-piece, as it changes its position, is the only evidence that it is working. ”

“ A separate hand pump is fitted for filling the boiler for starting, or at any time when it requires more water when the engine is not running, but on the Locomobile a steam pump is now provided so that steam once 'up' hand pumping need not be resorted to. ”

“ A small steam pump is furnished for pumping the water into the boiler. This device consists of a small steam cylinder connected directly with the pump plunger and is absolutely independent of the main engine so that it can be used whether the engine is running or not. The exhaust of the pump should be turned into the feed water heater when the engine is not running so as to heat the water, but should be directed to atmosphere when the main exhaust is passing through the heater. An injector is usually supplied with the engine for feeding the boiler in emergencies. ”

“ 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. ”

“ The pump at the lower right-hand corner of the engraving takes salt water through the suction at the bottom and passes it upward through the condenser and overboard through the circulation discharge. Any steam pump having a sufficient capacity may be used as a circulating pump.
169
ATMOSPHERIC PUMPS.
The Bliss-Heath Atmospheric Pumping Engine represented by Fig. 455 is novel in its construction, consisting of a low-pressure, upright, tubular steam boiler, having a safety valve loaded to carry 11⁄2 lbs. steam pressure. The large cover lifts under 2 lbs. pressure, hence explosions cannot occur. ”

“ The control can be arranged so that the pump is operated only at full load and high efficiency, and when not operating no power is being consumed, as is not the case with a steam pump where steam pressure must be maintained at all times. The electric driven pump is thrown into operation by a float controlled switch which is closed when the reservoir fills, and opens when the pump has emptied the reservoir. The choice between steam and electric power for large pumping stations is a matter of relative reliability and economy. ”

“ BOILER FEEDERS Injectors have a dangerous rival in the Moore Steam Pump or boiler feeder for traction engines, and the reason this little pump is not in more general use is the fact that among the oldest methods for feeding a boiler is the independent steam pump and they were always unsatisfactory from the fact that they were a steam engine within themselves, having a crank or disc, flywheel, eccentric, eccentric yoke, valve, valve stem, crosshead, slides, and all the reciprocating parts of a complete engine. ”

“ Power pumps and centrifugal pumps driven by constant speed electric motors have no overload capacity. A power pump or a centrifugal pump may be overloaded up to the maximum horse-power of any variable speed motor or steam engine driving it, provided the pump has been designed to permit it. Direct-acting steam pumps which are designed for proper piston speed and valve action at normal loads, can carry a 50 per cent overload for short periods, although the strain on the pump is great. They will carry a 20 to 25 per cent overload for about eight hours with less vibration and strain. ”

“ Engraving, Fig. 243, represents a Quintuplex pump used principally in mining operations, or wherever large quantities of water are to be delivered under high pressure in the shortest possible space of time. The pump here shown was designed to deliver 225 gallons of water per minute under a head of 1,200 feet. It has five plungers 4 inches in diameter each and having a uniform stroke of 12 inches.
These pumps driven by electric motors it is said represent the most economical method of transmitting power, as compared with the best designs of steam pumps. An efficiency of 80 per cent. ”

“ The oil is circulated by a pump directly operated from the turbine, except where the power-house is provided with a central oiling system. Particular stress is laid by the builders upon the fact that it is not necessary to supply the bearings with oil under pressure, but only at a head sufficient to enable it to run to and through the bearings; this head never exceeding a few feet. With each turbine is installed a separate direct-acting steam pump for circulating oil for starting up. ”

“ The energy expended in operating the power driven pump is obtained at the same economy as that required by the machinery in the mill or factory, and as a modern automatic cutoff engine will develop a horse power with considerable less steam than the direct acting steam pump the cost of the power required by the power driven pump is correspondingly less ”

“ It is due very largely to the numerous designs of steam valves, that difficulty has been encountered in managing single-cylinder pumps as successfully as those of the duplex type, the similarity of construction in the latter type, even in minor details, being much more marked.
The successful operation of a pump depends to a great extent upon the intelligence displayed in its management, and an engineer can scarcely hope to obtain quiet and smooth running pumps and freedom from breakdowns and perplexing delays except by a thorough knowledge of the details of construction and operation. ”

“ The pump-rod, I, works a double-acting pump, J, and the resistance to the issuing water is rendered uniform by an air-chamber, K, within which the water rises and falls when pressures tend to vary greatly. A revolving shaft, N, driven from the fly-wheel shaft, carries cams, O P, which move the lifting-rods seen directly over them and the valves which they actuate. Between the steam-cylinders and the columns which carry the beams is a well, in which are placed the condenser and air-pump. Steam is carried at 60 or 80 pounds pressure, and expanded from 6 to 10 times. ”

“ If there be nothing to be removed but the condensed steam, a very small pump ought to be sufficient. It is not wonderful that a good vacuum is sustained in the condenser, if the power expended on the air-pump is employed in pumping away uncondensed steam. Such a contrivance would be merely a deception, giving an apparent but no real advantage to the engine. ”

“ They serve to promptly relieve the upper pump discharge chambers of air, and may be closed as soon as water escapes from their orifices.
When cylinder condensation has nearly ceased, the engine being warm, the drain cocks should be closed and the machine speeded up gradually until a good pressure of steam is obtained.
Until the engineer has had some experience with the machine, and is familiar with its workings, it is not advisable to use more than 90 or 100 pounds of steam, which is all that is required for ordinary fire duty; the necessity for more than 120 pounds will probably never arise. ”

“ A steam pumping engine, which furnishes water under high pressure to raise loads by means of hydraulic cranes, is not more truly a heat engine than a simple boiler, for the latter converts the latent energy of fuel into the latent energy of steam, just as the pumping engine converts the latent energy of steam into the latent energy of the pumped-up accumulator or the hoisted weight. ”

“ At their lower ends a single valve serves as exhaust-valve to the high-pressure and as steam-valve to the low-pressure cylinder. The pistons move in opposite directions, and steam is exhausted from the high-pressure cylinder directly into the nearer end of the low-pressure cylinder. The pump, of the “Thames-Ditton” or “bucket-and-plunger” variety, takes a full supply of water on the down-stroke, and discharges half when rising and half when descending again. The duty of this engine is reported by a board of engineers as 103,923,215 foot-pounds for every 100 pounds of coal burned. ”

“ The packing of the piston and of the pump glands, if the engine has pumps, should be known to be properly set up, bearing in mind that a leaky pump gland lets air into the pump and impairs its action.
The sand box should contain dry sand, as wet sand will not feed properly.
If steam is raising too rapidly, close the lower damper to reduce the consumption of fuel and save blowing off steam through the safety valve, which should always be avoided as much as possible. ”

“ Before connecting the steam pipes, blow out with steam pressure the chips and dirt in the steam pipes. Always use the union furnished with the pump. It has a gauze gasket in it to catch the dirt that may get into the valve. Before starting pump, open air cock in delivery pipe and turn exhaust lever back, away from the air chamber. Then open throttle valve wide and allow pump to exhaust into the air until it takes suction, when deflecting lever may be thrown forward toward air chamber and cold water in the pump will condense the exhaust and return it to the boiler. ”

“ This is the reason given in support of the claim that the rotary engine forces water to a given distance with from one-fourth to one-third the steam-pressure necessary to drive all reciprocating engines. The smaller amount of power necessary to do the work, the less strain and consequent wear and tear upon the whole machine, are said to make it more durable and reliable. The pump being chambered, its liability to injury by the use of dirty or gritty water is lessened, and it is stated that it will last for years, pumping gritty water that would soon cut out a piston-pump. ”

“ It is, however, often best to put in a larger pump than the existing boilers could drive at full capacity, as a small boiler will drive a 750-gallon pump at the 500-gallon speed with very nearly as good economy as it can drive a 500-gallon pump at full speed. The pump then does not have to be changed when the plant is enlarged and the boiler power increased.
A steam piston relatively larger than necessary is a source of weakness. It takes more volume of steam, and gives more power with which to burst the pipes if the throttle is opened wide suddenly during excitement. ”

“ A.--It would be a material improvement if a feed pump was to be set in the tender and worked by means of a small engine, such as that now used in steam vessels for feeding the boilers. The present action of the feed pumps of locomotives is precarious, as, if the valves leak in the slightest degree, the steam or boiling water from the boiler will prevent the pumps from drawing. It appears expedient, therefore, that at least one pump should be far from the boiler and should be set among the feed water, so that it will only have to force. ”

“ This pump has no outside valve gear, arms or levers; all movable parts are inside and enclosed, to prevent collision with the walls of the mine shaft nor is it likely to receive injury from blast explosions. Being fitted with special exhaust cut-off, it will continue to run as fast as steam will drive it (with an irregular or intermittent supply of water, or when the water fails entirely,) not only without danger of the piston striking the heads, but without injury to the valves. It is designed and intended to handle gritty water.
Telescopic pipe joint shown in Figs. ”