John Haswell: Hydraulic Forging Press
In 1861 John Haswell of Austria patented a hydraulic press for producing forgings.
The history of the application of hydraulic presses to the working of metal is by no means clear. Hydraulic presses had been used for a number of processes since their introduction by Joseph Bramah, and became very widely used in the first half of the nineteenth century for purposes such as baling cotton. It appears that during this period the Broughton Copper Co used hydraulic presses for compressing copper ingots.
Charles Fox applied hydraulic presses to the hot forming of wrought iron chain links in the 1840s.
A key difference between hydraulic presses used for baling, oil seed pressing, etc., and hot metal working is that the latter required to be fast-acting when forcing and withdrawing the ram.
It appears that hydraulic presses did not find wide early application in hot metal working, but things changed after 1861 when John Haswell developed a well-thought out design for producing steel forgings.
Details
Haswell's machine was described and illustrated in 'The Engineer' in 1861[2], and also in The Practical Mechanic's Journal in July 1863.
Fortunately, an 1872 example of Haswell's machine was saved and is prominently displayed in Vienna Technical Museum. See photos. It was made in the works of the Österreichischen Staats-Eisenbahn-Gesellschaft (StEG) (Austrian State Railway Co), of which Haswell was the Director.
Haswell's equipment comprised a press worked by high pressure water supplied by a steam-powered pump, of a type which would later be called a 'hydraulic intensifier'. The pump was simple in principle, having a large central steam cylinder containing a piston whose rod was extended out in both directions to carry a small diameter piston on both ends. The steam piston's area was very much greater than that of the hydraulic pistons, so the resulting hydraulic pressure was much greater than the steam pressure, in proportion to the ratio of the piston areas.
Steam was admitted to and exhausted from either end of the cylinder by a slide valve. This was worked by what we would now call a servo - an auxilary steam-powered cylinder. This was actuated by a manual lever, over-ridden by a tappet arrangement which reversed the steam piston at the end of each stroke. The servo is much like a steam engine cylinder, with the slide valve being positioned manually or by the over-riding tappet arrangement. The speed of movement of the servo, and hence of the main slide valve, is limited by a 'cataract'. The cataract is simply a closed cylinder containing oil and a piston. Oil can only migrate from one side of the piston to the other via a small bypass valve (see photo 10).
Photo 18 shows one of the pressure gauges registering steam pressure in the cylinder. The red line is at 14 kg/cm2 (200 psi).
The pressurised water acted on the vertical ram of the press to force it downwards. A very much smaller ram above the main ram returned the ram to the top of its stroke. High pressure water was admitted above the rams by a small manually-controlled valve within the cylinder. Another valve released the pressure. Although the valves were small, the high pressure imposed on them meant that considerable force was required to move them. This force was obtained by long levers operated by steam-powered servos, manually controlled by levers.
A 1250 ton press made to Haswell's patent, made by the Kirkstall Forge Co, was described and illustrated in 'The Engineer' in 1867[3]. See photo 19. The steam piston was 66" diameter, and the pump pistons were 6.5" diameter. The hydraulic ram was 30" diameter. The cast iron cylinder was 3" thick, and was reinforced by shrinking on two layers of hoops 2.77" thick.
1863 Newspaper Report
'SCIENTIFIC GLEANINGS. No. 101. HYDRAULIC FORGING PRESSES. We give the following very interesting remarks, as showing the direction the mechanical genius of the country is taking in forging and bending large masses of and also as making evident that the power to produce is limited only the means of applying them. .....
'At proper and uniform heat iron or steel is perfectly plastic, and has been found that either of these metals may be gradually pressed out into shapes of any size. In September, 1853, Mr, Henry Dubs, then of Warrington, and now of Messrs. Neilson’s, Glasgow, patented a hydraulic forging press for this purpose. The details appear to have been carefully worked out, but we are unable to say whether a press has been constructed and worked upon Mr, Dubs’ plans. His patent, we believe, has lapsed; and Mr. Haswell, of Vienna, not long since took out a patent for a forging press with some improvements upon Mr. Dubs’ plans, and he has made and successfully worked such a press at the Austrian States’ Railway workshops, of which he is manager, at Vienna. We believe this press, illustrated in the Engineer of August 16th, 1861 (vol. xii., page 94), weighs between 30 and 40 tons, and exerts a pressure of 600 tons. The drawings attached to the patent specification showed it to occupy a space of nearly 40ft. by 25ft., and we believe the first tender for its construction in this country was nearly £4,000. Even although this sum was evidently an excessive estimate, Mr. Haswell’s press is clearly capable of much simplification. There is a very large horizontal steam cylinder, the piston within which, by means of a rod or ram projecting through each cover, works two very large force pumps for getting up the pressure in the press, this has a large ram upon which the water is forced to bring it down and a smaller ram above, connected by a crosshead and side rods to the larger ram, to bring the latter up again after each blow. The various valves are worked means of small steam pistons in supplementary cylinders. Mr. Haswell states that this press will deliver its blows with nearly the rapidity of a steam hammer, and we understand that he has brought an 11in. square ingot of Bessemer steel down to 4in. at a single pressure : the largest steam hammer employed in Sheffield having nothing like this amount of power. Mr. Haswell, too, has pressed out a locomotive piston and rod, at one stroke, from a single bloom. .....'[4]