1849. 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



297 



ON A PNEUMATIC LIFT. 



On a Pneumatic Lift. By IMr. Benjamin Gibbons, of Shut- 

 End House, near Dudley. — (Paper read at the Institution of 

 Mechanical Engineers, Birmingham.) 



{With Engravings, Plate XVIII.) 



The Pneumatic Lift described in the present paper is employed 

 to raise the ore, coal, and limestone for charging; four smelting fur- 

 naces at Corbyn's Hall New Furnaces, near Dudley. In some dis- 

 tricts the levels of the ground admit of the furnaces being ciiarged 

 by wheeling the materials on a level platform from higher ground 

 to the top of the furnaces, but in general tliese have to be raised 

 by machinery to the level of the top of tlie furnaces, the heigiit 

 raised being' about 40 to 50 feet. The usual plan of raising the 

 materials is by an inclined plane, which rises from the ground to 

 the top of the furnaces at an angle of about 30°; there are two 

 lines of railway upon it, and a travelling platform on each line, 

 drawn up by a steam-engine by means of a chain passing over a 

 nulley at the top of the inclined plane. The two platforms ba- 

 lance one another, one of them descending while the other ascends, 

 and the top of each platform is made horizontal and works level 

 with the ground at the bottom and with the stage at the top of 

 the furnaces, so that the barrows of materials are readily wheeled 

 on and off the platforms; several barrows are carried by each plat- 

 form. A rack is fixed on the inclined plane along the centre of 

 each line of railway, and a catch is fixed on the moving platform 

 which falls into the teeth of the rack in ascending, for the purpose 

 of stopping the platform and preventing an accident in the case of 

 the chain breaking; but the use of this catch is found to be incon- 

 venient in practice, and is generally omitted. Tliere is a difliculty 

 in stopping the platform at the required level, and the inclined 

 plane is olijectionable from the space which it occupies and the 

 expense of its construction. 



Where the inclined plane cannot be employed, the power of the 

 steam-engine is not employed directly to draw up the materials 

 vertically by a chain, because of the difficulty in working it con- 

 veniently and safely, to stop the platform at the correct level for 

 wheeling the barrows on and off', and prevent the risk of serious 

 accident by the chain breaking, particularly in the night work. At 

 some iron works an endless chain is used for this purpose, with a 

 series of buckets fixed upon it, which are filled with tlie materials 

 at the bottom, and empty themselves into the furnace by turning 

 over at the top. This lift is not suitable for su)i]ilying more than 

 one furnace; and when tliere are more than one furnace it is most 

 advantageous to employ a lift that will take up tlie materials in 

 the barrows, ready for wheeling at the top to tlie different fur- 

 naces. 



Another plan for lifting vertically is by means of a water- 

 balance; the platform on which the barrows of materials are raised 

 is suspended by a chain passing over a pulley at the top, and a 

 bucket is attached to the other end of the chain ; the jilatform in 

 descending draws up the empty bucket, and when the platform is 

 loaded the bucket is filled with water until it overbalances the 

 loaded platform and draws it up. There is an important objection 

 to this plan, that the bucket descends with an accelerated velocity, 

 and a friction break has to be used to check the velocity to prevent 

 a violent concussion on stopping its momentum at the end of the 

 descent; this causes a risk of accident from breakage of the chains, 

 and the friction break is also liable to derangement and extensive 

 repairs. 



At the Level Iron Works near Dudley an instance occurred 

 where a vertical lift had to be introduced in consequence of the 

 furnaces being raised 16 feet in height; there were two furnaces, 

 originally 3+ feet high and raised to 50 feet, and at the original 

 height the materials were wheeled on the level to the top of the 

 furnaces. When the height of the furnaces was increased, the 

 materials were required to be raised 16 feet, and a vertical lift was 

 necessary in consequence of the situation being so much confined 

 by a canal as to prevent the adojition of an inclined plane. For 

 this purpose the author of the present paper constructed a pneu- 

 matic lift, worked by the pressure of the air from the blowing- 

 engine that supplied the blast for the furnaces. This lift was 

 designed with the object of avoiding the objections to the plans of 

 vertical lifting previously in use, and obtaining a safer and more 

 economical application of power. 



This Pneumatic Lift consisted of a heavy cast-iron cylinder, 

 4 ft. 4 in. diameter inside, closed at the top, and inverted in a well 

 filled with water, in which it was free to slide up and down like a 

 gasometer; this cylinder was suspended from the top by a chain 

 fastened to the circumference of a pulley which was fixed on a 



horizontal shaft above the level of the top of the furnaces. A 

 pipe from the air-main was carried down the well and turned up 

 inside the cylinder, rising above the surface of the water, and when 

 the blast was let into the cylinder through this pipe the cylinder 

 was raised in the water by the pressure of the compressed air 

 against the top; this pressure was about 2 lb. per square inch. A 

 platform for raising the barrows of materials was suspended by a 

 chain from another pulley on the same shaft as the former pulley, 

 and the platform was guided in its ascent by vertical framing. 

 The cvlinder was heavy enough to draw up the platform with the 

 load upon it by descending into the water when the blast was 

 withdrawn; anil the empty platform was lowered by admitting the 

 blast into the cylinder and thus raising it. The cylinder was 

 lowered again by opening a valve which let out the compressed 

 air, and its velocity of descent was regulated by opening this valve 

 more or less. The velocity of the platform both in rising and fall- 

 ing was completely under command, by regulating the opening ot 

 the valves for admitting or letting out the compressed air, and the 

 velocity was gradually checked towards the end of each stroke 

 with certainty and ease, so as always to stop the platform without 

 concussion. The height to which the cylinder was raised was only 

 5 feet, and the two pulleys were made of different diameters so as 

 to raise the platform 16 'feet; the load raised upon the platform 

 was about half-a-ton. 



This pneumatic lift has now been in constant work for thirty- 

 nine years, and has worked quite satisfactorily during the whole 

 time; it has not re(iuired any repairs except renewal of the chains 

 and repair of the rubbing parts. An accident happened once by 

 the chain breaking whilst lifting, and the platform fell about five 

 feet, causing a shock to the man going up with it, but no injury 

 was done to the machinery. 



An improvement on this pneumatic lift was made by the author 

 of the present paper, in constructing a lift on a considerably larger 

 scale at the Corbyn's Hall New Furnaces; this is shown in the 

 accompanying engraving, and was constructed at the time of 

 building the furnaces. The height to which the materials have to 

 be raised is 41 ft. 6 in., and the present plan was designed to pre- 

 vent the risk of an accident occurring through the breaking of a 

 chain. There are four furnaces supplied by this lift, which is fixed 

 between two of them, and the four furnaces are connected on the 

 same level by the staging at the top, on which the barrows of 

 materials are wheeled from the platform of the lift. 



In this lift the platform for raising the barrows of materials is 

 fixed on the top of the air-cylinder, and it is raised by the pressure 

 of the blast, the action being the reverse of the former plan. In 

 Plate XVIII. the lift is shown at the highest position in fig. 1, 

 and at the lowest position in fig. 2. A, is the air-cylinder, which 

 is 5 ft. 6 in. diameter, and 51 ft. 6 in long, constructed of riveted 

 wrought-iron plates averaging ;^-in. thick, the plates being -j^-in. 

 thick'in the lower part and -nr'"- >" t'^^ upper part; the cylinder 

 is closed at the top and open at the bottom, and has a throttle- 

 valve B, 8 inches diameter, in the centre of the top, which is 

 opened I)y pressing down the foot lever C, fixed upon the plat- 

 form. 



D, is the platform on which the materials are raised; it consists 

 of planking carried on timber bearers, which rests upon the edge 

 of the cylinder top, and upon four wrought-iron brackets E, E, 

 carried out di;.!goiially from the cylinder to steady the platform, 

 and fixed to two hoops passing round the cylinder. 



F, F, are four timber guides placed at the corners of the plat- 

 form, and connected at top to the level stage G, G, upon which the 

 barrows of materials are wheeled to the mouth of the furnace H. 

 These guides are faced with angle-iron on the inner edge, and a 

 corresponding angle-iron is fixed in a notch at each corner of the 

 platform D, to slide easily up the guides; the height that the plat- 

 form rises is 44 ft. 6 in. 



Four cast-iron balance-weights I, I, are suspended outside the 

 guides F, F, by chains which pass over the pulleys K, K, in the top 

 framing, and are attached to the four corners of the platform D. 

 These four balance-weights weigh about 6^ tons, and the air- 

 cylinder and platform together weigh about 7 tons; leaving an un- 

 balanced weight of about ^-ton to bring down the air- cylinder and 

 empty the platform. 



The air-cylinder A, descends into a well L, L, which is filled 

 with water to the level M; and it is guided by four rollers N, N, 

 6 inches long and 7 inches diameter, each of which works against 

 a strip of bar-iron riveted on the cylinder, 4 inches wide and tiie 

 whole length of the cylinder. At the bottom of the well a foun- 

 dation of timber O, is fixed, to form a stop for the cylinder in 

 descending, and the cylinder rests upon the timber when at the 

 lowest position by a ring of angle-iron riveted round the bottom 



39 



