Suction pipe

“ A. Leak in suction pipe, supply cut off by strainer being clogged, loose lining inside the hose, leak in the stem of valve, too little steam pressure to lift, dirt in the tubes, red lead blown or drawn in through steam or supply pipe, bad check valve, not lift enough or none at all, new boiler full of grease, wet steam, obstruction in the connection to the boiler.
If injector fails, examine at all of these points before condemning. The most common trouble is a leaky suction. ”

“ Whether a foot valve is used or not, a strainer should be attached to the suction pipe to prevent large substances from entering, that might choke or clog the pump, but be careful that suction area is not contracted. ”

“ The suction pipe I′′ of pump I extends into box K1, where it terminates in a turned-down nozzle provided with valve i having a lever handle and float z. As a given amount of liquid is constantly running into the box, should the pump run too fast the float lowers, partially closing the valve and lessening the amount of liquid drawn at each stroke of the pump, and preventing air from being drawn in, since the end of the suction pipe is always sealed by the liquid. ”

“ Men sometimes ask why, (if they can run a pump smoothly so as to get a delivery of 1,000 gals. per minute,) we should not accept as “a thousand gallon pump,” irrespective of its suction valve area or its exhaust port area or the size of its cylinders.
To this we reply that when new and favorably set almost any pump built according to these specifications can run at a much greater delivery than here rated, but when lift is unusually high or suction pipe long, or when the pump takes its suction under a head, no pump can be run so fast as on, for instance, a 5-foot lift. ”

“ Pressure gages were connected to the suction, discharge, and condenser inlet, as shown at G, G' and G'' respectively. When No. 1 unit was operating alone the gage G showed practically zero, indicating no vacuum in the suction pipe. Observing the same gage when No. 2 unit was running, a vacuum as high as 2 pounds was indicated, showing that No. 2 was drawing more than its share of cooling water from the main A and hence the circulating pump for No. 1 was fighting for all it received. ”

“ Should the pump operator, however, through a mistaken idea of the proper method of operation, think that the priming should be continued until all air was exhausted from the suction pipe and the pump running in normal condition, there would be some by-passing between chambers, but as there is a free vent for the air, the main result would be simply to limit the amount of air exhausted per stroke, from the main suction, by the amount of water which entered a chamber in this way. ”

“ A hydraulic dredge consists mainly of a centrifugal pump with its driving engine and boiler, and hoisting machinery for handling suction pipe and boat; the pump in operation creates a strong suction flow in the suction pipe, sufficient to pick up the material and draw it into the pump, from which it is again delivered through the discharge pipe any distance to point of delivery, and can at same time be elevated to reasonable heights. Sand, mud, silt, etc., are readily picked up by the suction force only, but where material is packed it must first be agitated. ”

“ For such situations, a steam ejector connected to the suction pipe near the pump is advised, and may be required in addition to the regular priming pipes and tank. The size of the ejector should be sufficient to exhaust the suction pipe within about three minutes. Such ejectors will be considered as extras not included in the ordinary pump fittings. ”

“ If it be of cast-iron, a large hammer may effect the purpose: on the water-pipe being broken, the suction-pipe of the engine is placed in the opening so made. If the pipe be of lead, the opening in the street should be made of sufficient length to admit of one end of it, when cut, being turned into the engine. If the supply of water by this means be so great as to occasion waste, it may be regulated by the nearest stopcock on the water-pipe, by driving a wooden plug into the end of a cast-iron pipe, or compressing the end of a leaden one. ”

“ Now suppose the plunger to move to the right, and as no more air can get into the pump, that already within it will expand, and will therefore become lighter, hence there will be less pressure on the surface of the water within the suction pipe than there is on the outside of it, and as a result the water will rise up the pipe, not because the plunger draws it, but because the air outside the pipe presses it up within the pipe. ”

“ A foot valve on a fire-pump suction is not advised except in very rare cases, as with a lift of 18 feet or a suction pipe 500 feet or more long. A foot valve is not needed when there is a good efficient set of priming arrangements as described above and it is commonly found this gives a false sense of security, and that with a fire-pump left standing several days the water will often be found to have leaked back, so that it is no better than if no foot valve had been used. ”

“ Two and sometimes three engines are worked by suction-pipe from one plug in this manner. The portable cistern is also used when the engine is supplied by suction, from water conveyed in carts or buckets, and is greatly preferable to any plan of emptying the water directly into the engine. By this latter method [Pg 148] there is always a considerable waste of water, arising both from the height of the engine, and the working of the handles; and, in addition to these objections only one person can pour in water at a time. ”

“ If this is true, tighten up the pump plunger stuffing-box nut a little. If now the pump starts off well, you have found the difficulty; but at the first opportunity you ought to repack the stuffing-box.
If the stuffing-box is all right, examine the supply suction hose. See that nothing is clogging the strainer, and ascertain whether the water is sucked in or not. If it is sucked in and then is forced out again (which you can ascertain by holding your hand lightly over the suction pipe) , you may know something is the matter with the first check valve. ”

“ There should always be a strainer on the suction pipe, also on the supply pipe, to prevent any particles of dirt getting into the valve. The pipes leading to and from the drainer should empty into an open sink where it can be seen. There is a possibility of the drainer valve leaking and then the water pressure will leak through it, causing a waste of water. If this leakage can be seen where it discharges, then the trouble can be rectified. The cellar drainer is connected directly with the water pressure and should have a valve close to the connection to control the supply. ”

“ Flue Cleaning. A 3 in. suction pipe has been run round the boiler-house in such positions that flexible hose can be attached for flue cleaning purposes. In this case the cleaners simply use an enlarged nozzle such as is supplied with a domestic equipment and the dust is removed from the flues, economizer soot chambers, etc., into the ash hopper without trouble or dust. ”

“ The revolutions will, of course, correspondingly increase, and under all ordinary conditions a pump should run smoothly at this higher capacity though a little more vibration and pounding would be expected than when running simply at its rated speed.
After cushion valves are adjusted there should be no noteworthy water hammer or valve-slam. Sometimes valve-slam is not the fault of the pump, but arises from an obstructed suction pipe. It is objectionable to doctor water hammer in a pump by “snifting” air into the suction, as this cuts down the efficiency and is a poor expedient. ”

“ Careful experiments on a large number of pumps of various makes at full speed, show that in a new pump with clean valves, and an air-tight suction pipe, and less than 15 feet lift, the actual delivery is only from 11⁄2 to 5 per cent. less than plunger displacement. This slip will increase with wear, and for a good average pump in practical use, probably 10 per cent. is a fair allowance to cover slip, valve leakage, slight short-stroke, etc. ”

“ It is clear then, that however high the pump may be above the level of the water, the water cannot rise more than 34 feet up the suction pipe, even though all the air be excluded from it and a perfect vacuum formed, because the propelling force, that is, the atmospheric pressure, can only raise a column of water equal in weight to itself, and it is found in practice to be an unusually good pump that will lift water thirty feet. ”

“ It is always best to use a foot valve in connection with centrifugal pumps where the lift is more than three to four feet, and even under these low lifts where long suction pipes are used to conduct water long distances, foot valves should always be used to keep the pump and suction pipe charged. ”

“ A pump with horizontal top discharge and short length of discharge pipe is sometimes difficult to start, especially if suction lift is high, owing to the fact that the water is thrown228 out of the pump shell before the water in the suction pipe has got fairly started, thus allowing air to rush back into the pump. ”

“ It is of advantage to carry four lengths of suction-pipe, as they can be joined to reach the water; if one is damaged the others will still be serviceable.
The suction-pipes are more troublesome to rivet than the common hose, and are done in the following manner:—After the joints are fixed on the spiral worm, and it is covered with the tarred canvas, an iron mandrel longer than the worm is put through it, the edge being rounded to the circle of the inside of the worm. The projecting ends of the mandrel are supported to allow the worm to lie quite clear. ”

“ A flushing apparatus for water-closets, consisting of the combination of a reservoir tank, a flushing valve controlling the outlet thereof, a flushing pipe for conveying water therefrom to the bowl of the closet, a suction injector arranged in connection with said pipe, and to be traversed by the descending flushing water, and a suction pipe in connection with said injector, whereby the water in flowing from said tank downward through the flushing pipe traverses said injector and sucks the air from said suction pipe. ”

“ This dredger is 220 ft. by 40 ft. by 17 ft. 2 in., and has a hopper capacity for 1250 tons of dredgings. The buckets have each a capacity of 25 cub. ft., and are able to raise 1000 tons of ordinary material per hour. The suction pump, which is driven by an independent set of triple expansion engines, is capable of raising 700 tons of sand per hour, and of dredging to a depth of 35 ft. below the water-line. The lower end of the suction pipe is controlled by special steam appliances by which the pipe can be brought entirely inboard. ”

“ Care should be taken when about to pack a boiler feed pump or other pump subjected to high pressure to see that the cylinders are relieved before loosening the cylinder head bolts. This may be accomplished by closing the valve in the delivery384 pipe, and also in the suction pipe; if the pump receives water under pressure, open the air cock on the air chamber and cylinder cocks. ”

“ With the stationary type cleaner you have no machine to move about—you simply move the tool attached to the hose and the tools are just as light as those of the portable machines. There is no electric connection to make, [59] no electric wire to carry unconsciously along. All there is to be done by the worker is to slip the end of the cleaner hose into the suction pipe opening in the baseboard of the room. A patented device prevents the hose from becoming detached accidentally.
The usual tools come with the installed cleaner, such as handle, blower, felted sweeper, book cleaner, duster, etc. ”

“ When the trench or ditch is too deep for the pulsometer to lift the water to the surface of the ground by suction, the truck can be run out on planks over the ditch, when the pump can be lowered to the necessary suction distance from the water. Suitable lengths of steam hose, with universal couplings, suction hose, also suitable lengths of light flanged galvanized pipe for the discharge, which can be readily connected may be carried on the truck, proper brackets being provided for their reception. ”

“ The Venturi tube (Fig. 55) consists of a pipe built up of two cones, placed vertex to vertex, to form a constriction. When air is forced through this at high velocity suction is produced in a small diameter tube taken off at the constriction. A suction of two centimeters of mercury, acting through holes about one centimeter equidistant from each other in the back plate, has been found adequate to hold flat a film 18 × 24 centimeters.
One merit of suction applied only at the moment of exposure is that the film-driving mechanism does not have to work against the drag of the suction. ”

“ The suction valves require more generous port-circumference and port-area than delivery valves because when a pump has to suck its supply through a considerable height or through a long pipe there should be the least practicable waste of the atmospheric pressure in getting the water into the plunger chamber, or in retarding it from following the plunger in full contact. With the water once into the plunger chamber there is plenty of steam pressure available to force it out through the delivery valves. ”

“ The induction system differs from the suction system in that the air flow along the pipe is induced by a jet of air, at very high velocity, fixed at any convenient distance from the intake nozzle of the conveyor pipe, and the material conveyed is discharged either from an open end into an open container, or by some form of cyclone. The closed discharger or container, with its baffles and rotary valves or air locks, is eliminated, and the substance to be handled has a free and unrestricted flow throughout the length of the pipe. ”