Hydraulic press

“ With the power pump, when the motive power is stopped, a leak, the size of a pin point, in a valve, will cause a leakage that releases the pressure and makes poor pressing. Be aware of the fact that there is no method of extracting water from the fertilizer so cheap as pressing and the only limit should be the strength of the cloths. Fig. 70 shows how a hydraulic press and pump should be connected.
FIG. 70.—DIAGRAM OF HYDRAULIC PRESS WITH PIPING AND PUMP.
Cooking Killing Stock. ”

“ When water reached it, it forced the edges apart, one against the plunger, the other against the walls of the recess, with a degree of tightness proportionate to the pressure. On water being released from the cylinder the collar collapsed, allowing the plunger to sink without friction.
The principle of the hydraulic press is employed in lifts; in machines for bending, drilling, and riveting steel plates, or forcing wheels on or off their axles ”

“ The great advantage of the beam press is, that it is impossible to apply the pressure in any other way but by a steady and gentle increase, as more weight is placed on the end of the beam. But after all, in intelligent hands the hydraulic press is preferable, for if it is properly used, the amount of pressure required may be exactly graduated. ”

“ This is the power used in the hydraulic press, a very simple machine of much value in the industrial arts when there is a demand for great force that can be slowly and steadily applied, as in compressing cloth, oil cake, paper, gunpowder and numerous other things. ”

“ Thus, with a hydraulic press no larger than a common tea-pot, a bar of iron may be cut as easily as a slip of pasteboard. The exertion of a single man, with a short lever, will produce a pressure of 1500 atmospheres, or 22,500 pounds on every square inch of surface inside the cylinder. ”

“ Whether parts are to be assembled by forced or shrinkage fits depends upon conditions. For example, to press a driving wheel tire over its wheel center, without heating, would ordinarily be a rather awkward and difficult job. On the other hand, pins, etc., are easily and quickly forced into place with a hydraulic press and there is the additional advantage of knowing the exact pressure required in assembling, whereas there is more or less uncertainty connected with a shrinkage fit, unless the stresses are calculated. ”

“ Machines of this kind are now usually driven by power. Hydraulic presses have been of late years introduced into many seed-oil mills in this country; but it is still a matter of dispute whether they, or the old Dutch oil-mill, with bags of seed compressed between wedges, driven by cam-stamps, be the preferable; that is, afford the largest product of oil with the same expenditure of capital and power. For figures of hydraulic presses, see Press, and Stearine. ”

“ It consists of a small hydraulic press, which forces a set of expanding bits or wedges into a bore-hole previously bored Coal-wedging machines. by a long screw augur or drill, worked by hand, the action of the press being continued until a sufficient strain is obtained to bring down the coal. ”

“ Every inch must be made good. Nothing must be left to chance or good luck. And fortunate it was that I insisted upon this cautious course being pursued; for, one day, while the hydraulic presses were at work, the bottom of one of them burst clean away! The cross-head and the chains, weighing more than 50 tons, descended with a fearful crash upon the press, and the tube itself fell down upon the packing beneath. Though the fall of the tube was not more than nine inches, it crunched solid castings, weighing tons, as if they had been nuts. ”

“ Those I am speaking of are men in authority. I am using the hydraulic presses brother Taylor brought into this country, and they are performing wonders. They will each press equal to a hundred and twelve tons weight. ”

“ In fact, we may consider the hydraulic press as a fluid lever with the water in tube C as the effort arm and that in cylinder A as the weight arm. The two arms are here so proportioned that the power arm must move thirty times as far as the weight arm. The work put into the press is exactly balanced by that we get out of it. An effort of 100 pounds exerted through a distance of thirty inches is exactly balanced by the moving of 3,000 pounds through a distance of one inch. ”

“ Forging of Large Pieces by Hydraulic Press Of late years much forging has been done, not by the hammer which gives such a sudden, superficial blow with shallow working of the piece, but by hydraulic or other press, which very slowly squeezes the hot piece to smaller and longer shape. Sir Henry Bessemer was one of the first to realize the advantages of and make use of the press for steel working. ”

“ For instance, there are machines for bending pipe, for curving railroad rails, for punching holes in metal, for pulling wheels off their shafts, for jacking up heavy weights, for baling cotton, paper, and other materials, all of which operate on the same principle as the hydraulic press. Water pressure is supplied sometimes by a hand pump, sometimes by a [100] power-driven pump, and sometimes it is taken from a reservoir in which compressed air imparts the requisite pressure to the water. ”

“ In fig. 910. two centres of motion for the pump-lever are shown. By shifting the bolt into the centre nearest the pump-rod, the mechanical advantage of the workman may be doubled. Two pumps are generally mounted in one frame for one hydraulic press; the larger to give a rapid motion to the ram at the beginning, when the resistance is small; the smaller to give a slower but more powerful impulsion, when the resistance is much increased. A pressure of 500 tons may be obtained from a well-made hydraulic press with a ten-inch ram, and a two and a one inch set of pumps. See Stearine Press. ”

“ The press cylinders are 12 in. diameter and are of crucible cast steel. To insure strength of construction and even distribution of strain throughout the press, all the columns, cylinders, rams, and heads are planed and turned accurately to gauges, and the pockets that take the columns, in the place of being cast, as is sometimes usual, with fitting strips top and bottom, are solid throughout, and are planed or slotted out of the solid to gauges. The pressure is given by a set of hydraulic pumps made of crucible cast steel and bored out of the solid. ”

“ The roots being put into a proper crushing machine are soon reduced to an uniform pulp, which in some manufactories is subjected to pressure wrapped in linen cloths under stone or iron rollers, and in others is placed in bags and placed under the Bramah or hydraulic press, the resulting juice being collected in proper receptacles. ”

“ The workman brings down a roller on this projecting part of the volume, and its pressure forces the free portion of end sheets over the sides of the jaws, thus forming the joint to receive the boards. With the backing the part of the work done by machinery ends. The backs are next coated with glue, pieces of calico for pasting down are laid on, and the entire back is covered with paper. "When dry, the volume is fitted into its cases and "pasted up," and the operations are finished by piling the cased books in a hydraulic press between boards, so as to leave only the backs projecting. ”

“ Roller and inclined segmental recess for silent feed motion.
1179. Gripping pawls and ring for silent feed motion.
Snail ratchet, No. 725.
Section 63.—PRESSING. The ordinary Screw press and Hydraulic press are well-known machines.
1180. Rack and screw press.
1181. Power press or stamp, with double crank movement worked from below.
1182. Dick’s anti-friction press, with rolling contacts throughout.
1183. Hydraulic press, with dies for lead pipe making; a similar press is used for making earthenware drain and flue pipes, the material being forced out of an annular orifice.
1184. Wedge press. ”

“ It is a decided disadvantage to have to move the plunger so far and in actual commercial practice hand-operated hydraulic presses are not worked in that way. A pump is used to force water into the cylinder so that a great many short strokes may be taken in place of one long one, and the pump handle provides an added leverage, enabling a man with little effort to exert an enormous lift. The water enters the ram cylinder through a valve, and the pressure is maintained on the ram until relieved by the opening of an outlet port. ”

“ While still in a molten condition in the mold, the steel used in manufacturing guns and shafting is subjected to hydraulic pressure until the ingot has cooled, thus insuring the solidity of the metal. The upper head of the compressor weighs 125 tons, and the lower one, including the cylinder through which the hydraulic pressure is applied, 135 tons. ”

“ The general features of hydraulic power transmissions are: (1) a central station where the hydraulic pressure is created, usually by means of steam pumping engines; (2) a system of distribution mains; (3) machines for utilizing the pressure. In cases of public supplies there is the further important matter of registration.
When dealing with any practical problem of hydraulic power transmission it is of the first importance to determine the maximum demand for power, its duration and frequency. ”

“ An air chamber of hammered copper and warranted tested under a hydraulic pressure not less than 300 lbs. per square inch is a little better than cast iron as it holds air better, and being lighter it wrenches and strains the pump less when running fast and shaking, but because it costs from $25 to $50 more than cast iron, it is not often adopted. ”

“ Meanwhile, a sufficient quantity of paper has been taken from the public store-house to the wetting-room. There it has been dampened, quire by quire, turned and laid in piles under the crushing pressure of an hydraulic-pump, worked by steam-power. When taken out the paper is ready for the press.
The rollers are brought from the room in which they are cleaned and kept, and set in the press. The ink fountain is filled. Sheet on sheet of spotless paper is placed aloft. The young woman who is to “tend” mounts to her perch. The steam-power is applied, and the printing begins. ”

“ In connection with their engineering works they carried on the manufacture of lead pipe by hydraulic pressure. The engine which drove a large section of their machine tools also drove the hydraulic pumps for this manufacture. It was a very trying service. The resistance was very heavy and came on and off the engine instantly. The action of the common governor was not prompt enough to control it, and they had to employ a man handling a disk valve with a very short motion. ”

“ Hydraulic pressure generated by the Stage I pump is used by the servo actuators to gimbal the thrust chamber during Stage I flight.
The Stage II hydraulic system provides hydraulic pressure to the Stage II engine, roll control, and vernier actuators. During sustainer engine firing, the hydraulic system is powered by the turbine pump assembly driven pump. At sustainer engine shutdown the electric motor driven pump starts and supplies hydraulic power to the vernier rocket motor actuators. ”

“ Water-pressure has sometimes been applied to operate machines which are worked continuously and not intermittently, and to continuous working rotary machines. This is unwise, for in applying hydraulic power to the continuous working of shafting or shop tools, the amount of power developed by the hydraulic engine cannot be varied to suit the work to be done, neither can the speed be regulated with sufficient nicety. ”

“ It is this principle which operates with such astonishing effect in hydrostatic presses, of which familiar examples are found in the hydraulic pumps, by the use of which boilers are tested. By the mere weight of a man’s body when leaning on the extremity of a lever, a pressure may be produced of upwards of 20 tons; it is the simplest and most easily applicable of all contrivances for increasing human power, and it is only limited by want of materials of sufficient strength to utilize it. ”

“ In steam engines a piston is alternately pushed forward and back in its cylinder by steam; and by means of the rod to151 which the piston is secured, motion is communicated to a crank and fly-wheel, and through these to the machinery to be driven: it is the same with pressure engines when used to move other machines, except that instead of the elastic vapor of water, a column of that liquid drives the pistons to and fro.
Note.—“The hydraulic engine of Huelgoat, in Brittany, is used to drain a mine; is single-acting, and acts directly to lift the piston of the pump. ”

“ In these cases, an artificial source of water power is created by using a steam engine to pump water to a reservoir at a great elevation, or to pump water into a closed reservoir in which there is great pressure.
Water flowing from the reservoir through hydraulic engines gives back the energy expended, less so much as has been wasted in friction. Where a continuously acting steam engine stores up energy by pumping the water, while the work done by the hydraulic engines is done intermittently,—this arrangement is considered the most useful. ”

“ Water under pressure conveyed in pipes is a convenient and economical means of transmitting energy and distributing it to many scattered working points. Hence large and important hydraulic systems are adopted in which at a central station water is pumped at high pressure into distributing mains, which convey it to various points where it actuates hydraulic motors operating cranes, lifts, dock gates, and in some cases riveting and shearing machines. ”