There are certain well-known difficulties and contingencies in installing and operating mine pumps: 1, The location of the mine is usually remote from supplies and any renewals or repairs which may be needed, are liable to be attended with excessive costs and delays; 2, The nature of the water in the mines is so highly acidulous that corrosion takes place in an incredibly small space of time. The action of sulphuric (diluted) acid which is found sometimes as high as two parts out of a hundred begins at once and continues until the iron or steel is destroyed; 3, The dust, grit, mud, etc., becomes mixed with the oil used to lubricate the pump; these ingredients find their way into the stuffing-boxes and cut the plungers. Hence, ample and unusual precautions are made to overcome the foregoing conditions. Extreme care has to be used in securing all movable parts of the machine and the connecting pipes. The plungers are generally outside packed and handholes are arranged to permit free access to the water valves. Fig. 438.—See page 148. When pumps used in mining service assume large proportions, they are almost invariably described as pumping engines; there is no real difference between the two except the proportions. The same combination of engine and pump in the smaller sizes used for boiler feeding, etc., are called steam pumps. Note.—The cost of repairing a half-inch globe valve which “gave out” in a mine in Venezuela, South America, was represented in a $45. machine charge and a mule ride of 35 miles to the shop containing a foot lathe and the same distance back to the mines. The cost in a more favorable location would be less than a dollar. The Cataract steam pump, Fig. 437, is largely used in mining operations. Many years service has proved its peculiar and curious merits. Large columns of water may be raised to great elevation or forced against heavy pressures without shock or jar of any kind and with safety to the machinery and connections; abrupt and violent action of the water is also avoided. The Cataract, it may be explained, is a regulator invented by Smeaton for single-acting steam engines. John Smeaton, the inventor, was an English civil engineer born in 1724 and died in 1792. The device derives its name from its similarity to the optical disease—a cataract—as it is a supplementary or sliding cylinder with its piston attached very curiously to the main valve stem of the engine. This cylinder—called the Cataract cylinder—is filled with oil which flows back and forth through a port connecting its two ends. This port is controlled by a valve which increases and diminishes the flow of the oil through the port. By means of the Cataract, the movements of the main steam valve are automatically graduated and controlled, so the speed of the piston is reduced as it nears the end of its stroke, allowing the valves to seat themselves gently and quietly, and the moving column of water to come to a gradual and easy rest. The claims of this construction of pumps have been thus summarized— 1st. The speed of the piston is automatically slowed down at the end of its stroke, giving time for the column of water to come gradually to rest, and for the valves to seat gently and quietly, avoiding all concussion, jar, or the slightest tremor. 2d. The speed of the engine can be adjusted and automatically maintained as desired under any pressure. Should it be working under full head of steam and against a heavy pressure, and the pressure be instantly removed the speed would continue unchanged. 3d. The piston works to the end of its stroke under all pressures, avoiding the waste of steam incident to the piston falling short of its stroke. It will be understood that there is only a slight waste of oil caused by the use of this apparatus—all the waste that there is, being the small amount leaking through the stuffing boxes. The term “Isochronal,” pump meaning equal spaces in equal times has been applied to both these pumps and their valve gear. The sizes, capacities, etc., of the pump described on the opposite page are given in the following Table.
The above table is based on a steam pressure of 45 to 50 pounds per square inch of steam piston, and the vertical height is from lower end of suction pipe to discharge. Fig. 438 is designed to show a pump largely used by miners in prospecting. It is double levered so that four men or more can operate it, two to each lever. The plunger and valves are so designed that they will lift muddy or gritty water without injury to these parts. An electric mining pump is shown on page 276, part one. This is a portable pump mounted on a car running on rails and is designed for the work appertaining to a mine in steady operation. On page 340, part one, is illustrated a powerful pump with four outside packed plungers designed for mining purposes. SINKING PUMPS.These special mining pumps are used to drain water from the shaft bottom, so that work in deepening or repairing may be carried on. As shown in the illustration they are made to be suspended by a chain or bail attached to eye-bolts in the upper cylinder head at points of support which will enable the pump to hang vertically and be raised and lowered at will. Fig. 439. The bail is so constructed that while the pump is suspended the cylinder head can, if necessary on the smaller sizes, be removed and the steam piston examined and adjusted. As the shaft gets deeper the chain may be lengthened out and an extra joint placed on the end of the delivery pipe. The sinking pump is subjected to the hardest usage of any, hence any steam pump that is to be used in sinking a mine shaft must be strong, certain in operation, capable of handling gritty water and require little attention. Fig. 438 exhibits a hand-power mining pump, designed especially for prospecting, etc., and made by the Edson Manufacturing Co., Boston, Mass. It is listed for three sizes: No. 6, capacity 1200 gallons per hour, 1 man. No. 8, capacity 4000 gallons per hour, 2 men. No. 10, capacity 6000 gallons per hour, 2 men. The outfit which usually goes with this diaphragm lift and force pump includes special suction and conducting hose, brass The Deane single vertical sinking pump is shown in Fig. 439; a table of dimensions and capacities of this pump is also given below. The pump illustrated is double acting and of the differential plunger type; the water end is in three parts and consists of a water cylinder, a lower plunger and an upper plunger. The water passes directly up and through the plungers, both of which are hollow. These plungers are outside packed. The water valves are reached by hand holes provided for that purpose. Split pins are used in the ends of the bolts to prevent the nuts from working off. These pumps are designed to stand a working pressure of 150 lbs. to the square inch. They have the regular Deane valve motion and will work under water. Table.
This table refers to Fig. 439. Fig. 440. Fig. 441. The Cameron vertical plunger sinking pump is shown in Figs. 440 and 441. Fig. 442. Fig. 443. This is one of the most successful mine sinking pumps designed; there are no parts exposed to rust, and instances have occurred when this pump has started off and cleared a shaft of water when the pump itself had been buried for weeks under a mass of fallen rock and debris. 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. 442 and 443, supplies a convenient means for lifting and lowering a sinking pump, and is usually made in lengths of sixteen feet. This enables the operator to drop the pump that distance without disturbing the rest of the pipe; by its use irregular lengths of pipe can be added, whereas, otherwise when the pump is lowered the pipe would have to be cut of equal length. The inside pipe is brass tubing which freely slips through the packing and is non-corrosive. Fig. 441 exhibits the sinking pump in practical operation; it is the same as that shown on the previous page. Note.—Mining pumps require to be made “to gauge” and interchangeable; an advantage which commends itself to experienced mining engineers. Many “parts” should be provided in duplicate on account of the rough usage and hard service alluded to above. The “Scranton” pattern of a mining pump is illustrated by the cuts shown below (Figs. 444 and 445). Fig. 444. Fig. 445. The plungers of this machine work through middle, exterior stuffing-boxes, into four separate and distinct water cylinders. The valve areas and water ways are unusually large in proportion to the displacement of the plunger, so that the velocity and consequent destructive action of the water currents is decreased in passing through the pump. These pumps are designed to withstand safely a working pressure of 250 pounds to the square inch, and all their attachments are especially strengthened with a view to meeting the rough usage and hard work to which they are liable to be subjected in mining operations. Fig. 446. Table.
The Worthington Pressure Pump. This pump, presented in Fig. 446, is specially designed for use in connection with hydraulic lifts and cranes, cotton presses, testing machines, hydraulic riveting and punching machines and hydraulic presses of all kinds. Also, for oil-pipe lines, mining purposes and services requiring the delivery of liquids under heavy pressures. There are four, single-acting, outside-packed plungers, which work through the ends of the water cylinders, the latter having central partitions. The arrangement of compound steam cylinders shown in Fig. 445, or a triple expansion arrangement, can be applied to these pumps where a saving of fuel is desired. The water valves are easily accessible and are contained in small independent chambers, capable of resisting very heavy pressure. These are made both horizontal and vertical; the prime consideration being in all cases the amount of floor space the pump will require. This is especially true in reference to small steam vessels, pleasure craft, etc. Owing to the unusual corrosion, caused by galvanic action, salt and various impurities, marine pumps are built of iron with brass linings, but frequently with the entire water ends of bronze. The arrangement of the water valves in the most approved forms of vertical pumps is such that the pistons are always submerged, and the water valves sealed, thereby securing immediate lift of water through the suction pipe, and steady, quiet operation of the pump; many horizontal pumps of the ordinary duplex design are also used on shipboard. The ship’s pump is common to all vessels and used to keep the “hold” free from water. It is usually worked by hand but it is the law in certain countries that the “ship’s pump,” aside from steam vessels—shall be driven by windmill power; it is said to be an odd sight to see the practical working of these at sea. Fig. 447. The illustration on page 156 shows a marine vertical pump of the Davidson pattern, designed to work against a pressure of 250 pounds per square inch. The table given herewith will show the sizes and principal details of these pumps. Table.
The capacity for boiler feeding in the table is based upon sixty single strokes for each pump per minute. The suction and discharge openings, as will be seen in the figure, are on both sides. The water piston is packed for hot and cold water and special valves are furnished as may be necessary. The Worthington wrecking pump, Fig. 448, was constructed many years ago, for wrecking, drainage, or irrigating purposes, and has proved itself to be remarkably well adapted to such service. It is used generally by the Wrecking Companies on the Atlantic and Pacific coasts and the lakes, and is constructed with special reference to reliability, portability and general efficiency. It is also well adapted for other services requiring the delivery of large quantities of water within the range of lift by Fig. 448. The ordinary slide valve is employed, moved by an arm striking against tappets on the valve rod. No auxiliary valves are used in connection with it. The water valves are of rubber, the lower ones being upon a permanent plate at the bottom of the pump. The plunger also is covered with valves. These last open for the passage of water when the piston descends. On account of its short stroke and large diameter, this pump is extremely efficient, running on comparatively low pressure of steam, and with a very small percentage of loss from friction or leakage. It is also simple and durable, with few parts. The stated capacities of the pumps given in the table can be exceeded in cases of emergency. Table.
This machine is constructed to meet the requirements of steamship builders and is recognized and adopted by marine engineers of this and of other countries as the standard design for this service and for oil tank steamer work. It will be observed, see Fig. 449, that its proportions are such as to secure the advantages of large pumping capacity with unusual compactness and moderate weight. This pump is of the packed piston type, and has the valves so arranged that the water pistons are always submerged, thus making it particularly well adapted for long and difficult suction lifts such as are met with in steamers carrying petroleum in bulk, and in steamers having extensive systems of water ballast tanks. The demands for water ballast service are generally met by the following two sizes, as shown in the table below. Fig. 449. Table.
The purposes for which pumps are used on shipboard, aside from the air and circulating pumps for condensers, are: (1.) Feeding the boiler. (2.) Emptying the tanks and pumping out bilge. (3.) Supplying water for washing down decks, extinguishing fires, filling evaporators and sanitary service. A special pump for each separate purpose is not always supplied, but one pump may have the necessary pipe connections to serve alternately various duties. Feeding the boilers is so important an operation that a supplemental special pump is always required. To make absolutely sure of an ample supply of feed water one of the other pumps is made strong enough to serve the same purpose, or sometimes an injector is fitted as an auxiliary feeding mechanism. A bilge pump has special fittings, for the reason that it handles very dirty water, undesirable to be transmitted through any other pipe system. In small ships, however, one pump, the so-called “donkey,” often serves for nearly all other purposes, including auxiliary boiler feeding. A special form of pump in use on Western river steamers is the so-called “doctor,” an independent pump with a walking beam, by which one steam cylinder drives a system of pumps for feed, fire and bilge pumping purposes (Fig. 450). The feed pump should be of simple construction, great strength and ample capacity, to secure great regularity and reliability of service under the severe conditions of high pressure. The main parts of auxiliary feed pumps are often duplicated. This is a desirable point, as one set of spare parts in piston, rings, valves, etc., is suitable for both pumps. 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. 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. The hot water pumps, 31/2 diam. × 10 stroke, have chambers bored and are fitted with a copper and tin composition for valves and scats; the latter are driven into their places and riveted over underneath. Fig. 450. Note.—Each valve is reached by removing the bonnet covering it. The joints under caps are made the insertion of sheet lead. The heaters above the frame, as shown, are 22 × 5' 0 long, of hard rolled copper, with a copper worm 18' 0 long by 21/2 diameter in each. There is also a baffle plate above the water line in each heater to prevent the exhaust from throwing the water out at the top. HYDRAULIC GAUGE TEST PUMP.These gauges are apt to get out of order for various reasons namely, there is no theoretical method of determining the motion of the pointer due to a given pressure; this is done by tests in which known pressures are employed, and accordingly the divisions on the graduated scale are usually unequal, hence these instruments are tested by attaching them either to a mercury column, or to a dead weight safety valve having for its seat an exact square inch surrounded by a knife edge, or a piston of standard area loaded with weights. This sharp edge is covered by a fibre washer of leather for moderate pressures, say 150 lbs. per square inch, or vulcanized fibre or its equivalent for higher pressures. Fig. 451. Fig. 451 represents a pump that can be used for pressures up to 10,000 lbs. per square inch. The Hand-Lever Pump shown at the right in cut is used for filling the Pressure Pump cylinder and connections with oil or glycerine, and may also serve for testing gauges of low pressures up to 15 or 20 lbs. The suction pipe a is connected with the reservoir containing the oil or glycerine, which after being used is discharged by valve d and returned into the reservoir by pipe c. In filling the pump the cylinder spindle has to be screwed all the way out, and the valves b and d closed before it is put under pressure. Fig. 452. “SUGAR-HOUSE” PUMPS.The handling of semi-liquids, commercially known as thick stuff, has always been considered more or less of a serious problem, and many designs of mechanism in the form of pumps have been invented for that purpose. For pumping tar the improved forms of rotary pumps have recently come largely into use. These will be described later under their proper heads. Fig. 212, page 232, Part one, represents a very satisfactory design of plunger pump for handling the heavy stuff alluded to. The Deane single sugar-house pump is shown in Fig. 452. These are largely used for pumping molasses, syrup, cane-juice, melter-pan products, etc., and are fitted with linings, valves, etc., to best suit the condition of the fluid to be pumped. The valves are very large and the motion of the pumps is somewhat slower than for water. By removing one set of bolts all the valves are uncovered. These products of the sugar-house when of a high temperature can be pumped nearly as fast as water; the following list gives the approved proportions of these pumps. Table.
The Single Magma Pump. The term magma includes any crude mixture, especially of organic matters in the form of a thin paste, it also means “a confection,” hence, the name given to the pump illustrated in Figs. 453 and 454 is very appropriately applied to a sugar-house apparatus. It is designed for pumping various thick heavy mixtures and semi-liquids and for moving massecuite, second and third sugar. Fig. 453. Fig. 454. The construction in Fig. 453 is such as to insure strength and certainty of operation; there are no intricate small parts, and the interior is readily accessible. These pumps are made with brass-lined cylinders, or cylinders and fittings entirely of composition when needed to overcome the difficulties appertaining to pumping acidulous and corrosive liquid substances. The single fly-wheel magma pump as shown in Fig. 454 represents the highest type of machine for this class of work. The steam end is of the plain slide valve pattern. It is fitted with a heavy fly-wheel, perfectly balanced. The admission of steam is regulated by a throttling governor of approved design. The fly-wheel and governor insure a uniform speed of the pump under variations of load—hence the fly-wheel pump does not require adjustment of throttle for every variation in water pressure, as is necessary with direct acting pumps. The following table applies to the two styles of the magma pumps—with and without the fly-wheel, as the pump ends are the same in both. Attention is called to the number of strokes per minute (thirty) shown in the table as compared with the number of strokes (100 and 125) called for in the previous table. This is caused by the different viscosity of the stuff to be handled by these machines. Table.
CIRCULATING PUMPS.The definition of the word circulation conveys the best idea of this mechanism—“The act of moving in a circle, or in a course which brings the moving body to the place where its motion began,” hence, a circulating pump is one which causes the water to flow through a series of pipes or conduits, as for example, the water in a steam boiler as in the Ahrens Fire Engine, see page 126, Fig. 426, or in marine boilers, or forces cooling water through a surface condenser. A centrifugal pump driven by an independent engine, see page 219, Fig. 497, is generally used for the latter purpose. Fig. 454A. The annexed engraving, Fig. 454A, represents a circulating pump attached to a salt water evaporator and distiller for recovering fresh water at sea. 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. 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. Fig. 455. Note.—The safety valve is shown on the floor alongside of the hand bar arranged to work the feed pump. Fig. 455. The motor is a simple atmospheric engine operating a plunger pump and a single acting air pump. The operation of this motor is almost noiseless. The motive power is the normal pressure of the atmosphere (14.7 lbs. to the square inch), utilized by the formation of a vacuum in the power cylinder. The air is expelled from the cylinder by admitting steam without appreciable pressure, i.e., to balance that of the atmosphere, after which the steam exhausts into the surface condenser, in which a constant vacuum is maintained. Steam is then admitted automatically into the power cylinder, breaking the vacuum and imparting to the piston the required impetus. This principle is identical with that of the ordinary condensing steam engine, with the exception of the very low steam pressure in this connection. Fig. 456. This engine can be operated satisfactorily in combination with an ordinary house-heating boiler (low pressure), hence the expense of running it is very low during the steam-heating The bearings are self-oiling, and the cylinder condensation furnishes ample protection for the inside of the engine cylinder. There are no leather packings to burn out, and this is remarkably free from the objections to the older types of caloric engines. These pumps when required will force a proportionate quantity of water to a greater height than fifty feet, upon which the following table is based: Table of Approximate Dimensions and Capacities.
In pumping ammonia it is of the greatest importance that this mechanism be simple and compact owing to the peculiar properties—oftentimes dangerous—inherent to ammonia. The plain slide valve with crank, shaft and fly-wheel probably is less liable to give trouble than many of the other styles of pumps, and a full stroke is always assured. The pump here presented (Fig. 456) occupies little floor space and is easily accessible; the bucket plunger is used and also a slotted yoke in place of a connecting rod. The column is in two parts bolted together. In case of accident to either part duplicates may be quickly substituted. THE WOOD PROPELLER PUMP.The pump shown herewith lifts the water by propeller screws or “runners,” each consisting of two half-circular inclined blades fastened to a shaft at intervals of 3 to 5 feet, and of slightly less diameter than the casing, so as to revolve freely within it. Experiments have demonstrated that more water can be raised with a given speed by putting the runners close together near the bottom of the pump. A bearing for the shaft is placed immediately underneath each of the runners, and held in position by a set of spring “guides” attached lengthwise to the well-casing. These guides interrupt the whirling motion of the water as it is thrown upward by the runners, and turns it back in the opposite direction, thereby delivering it into the revolving runners in a direction opposite their motion. By this method the whirling motion of the water is utilized and the capacity of the pump largely increased without a proportional increase of power to run it. With this pump, water may be raised from several hundred feet below the surface by extending the shaft and runners down the well-casing to the desired depth; it being always necessary to submerge the lower runner. As the shaft rotates the lower runner lifts the water up to the runner above it, and so on to the next, until the water is delivered at or above the ground if desired; the distance depending upon the size and pitch of the runner, the number of runners, and the speed at which they are driven. Speed is not increased for additional depth, because more runners are added, and this compounding of the runners increases the efficiency of the pump. A ball bearing is placed over the stuffing-box to carry the entire weight of all the movable parts of the pump, and also the column of water. In deep wells cone roller bearings are used in place of the ball bearings. The pumps are made to fit all sizes of wells and of any desired capacity. Runners of various pitches are made for the different sizes in order to suit the supply of water or the power available. If, after testing, the supply of water in the well is found to be limited, the runners are changed to raise the amount of water due to a given horse-power, then runners can be furnished with a pitch suited to lifting that particular amount of water. Fig. 457. For example, if one runner at a given speed, gives 10 pounds pressure per square inch, then two runners would give 20 Fig. 458. Where the water is beyond the suction limit this pump can be used to raise the water to the surface, discharging into the suction of the force pump. In this manner, whatever surplus of power the propeller pump might have in raising the water to the surface, would be utilized in helping the water through the force pump. The speed of rotary pumps is generally high, ranging from 800 revolutions per minute for the small sizes to 250 revolutions for the larger sizes. In a number of experiments made upon this form of pump the highest efficiency was obtained with pressures ranging from 30 to 50 pounds per square inch, and speeds ranging from 475 to 575 revolutions per minute. The average efficiency of the rotary pump is from 48 to 52 per cent. THE SCREW PUMP.The engraving herewith, Fig. 458, exhibits the general construction of the Quimby screw pump. The four screws that act as pistons in propelling the water are mounted in pairs on parallel shafts, and are so arranged that in each pair the thread of one screw projects to the bottom of the space between the threads of the opposite screws. The screw threads have flat faces and peculiarly undercut sides; the width of the face and the base of the thread being one-half the pitch. The pump cylinder fits the perimeters of the threads. Space enough is left between the screws and the cylinder and between the faces of the intermeshing threads to allow a close running fit without actual contact. There is no end thrust of the screws in their bearings, because the back pressure of the column of liquid is delivered through the suction, S, at the middle of the cylinder, therefore the endwise pressure upon the screws in one direction is exactly counterbalanced by a like pressure in the opposite direction. The suction connection opens into a chamber underneath the pump cylinder. The suction liquid passes through this chamber to the two ends of the cylinder and is forced from the ends toward the center by the action of the two pairs of intermeshing threads; the discharge being in the middle of the top of the cylinder, as shown at D. The power to drive the pump is applied to one of the shafts, and the second shaft is driven by means of a pair of gears, shown at G. The pump has no internal packing, no valves and no small moving parts. The only packing is in the stuffing-boxes where the two shafts pass through the cylinder head. Whether driven by a belt, an electric motor, or a steam engine, the driving power is applied directly and without the loss due to intermediate mechanism; as the screws are not in contact with the cylinder or with each other, the consequent absence of wearing surfaces gives the pump great durability. These pumps have a high efficiency against a wide range of pressures: The power being applied direct, the thrust due to the back pressure of the column of liquid in the delivery pipe is balanced. As the action of the screws on the liquid is continuous, the delivery is free from pulsation. By thus keeping the liquid in constant and uniform motion the efficiency of the pump is increased and the pump is made peculiarly suitable for certain specific purposes as there is no churning effect upon the liquids handled. These pumps are much used in connection with hydraulic elevators by pumping directly into the elevator cylinders, as there is no pulsation. They are also used to pump oil into pipe lines and are driven by electric motors as well as by belts. For circulating pumps for brine and for fire purposes these pumps have certain peculiar advantages. Table of Dimensions and Capacities of the Quimby Screw Pump.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
