US1383399A - Steam hydraulic intensifier - Google Patents

Description

T. w. HAND.

kSTEAIIII HYDRAULIC INTI'INSIFIIR.I

APPLICATION FILED FEB. 26| 1919.

1,388,399. Patented July 5,1921.

2 SHEETS-SHEET I.

T. W. HAND.

STEAM HYDRAULIC I'NTENSIFIER.

APPLICATION FILED FEB. 26,1919.

Patented July 5, 1921.

UNITED STATES PATENT OFFICE.

THOMAS WILTON HAND, 0F SHEFFIELD, ENGLAND, ASSIGNOR TO DAVY BROTHERS,

- LIMITED, OF SHEFFIELD, ENGLAND.

STEAM HYDRAULIC INTENSIFIER.

Application filed February 26, 1919.

To aZZwwm ff/mcy concern: v

Be it known that I, THOMAS WILToN HAND, a subject of the'King of Great Britain, residing at Sheffield, England, have invented new and useful Improvements in Steam Hydraulic Intensifiers, of which the following is a specification.

When a hydraulic forging` or like press, actuated by a steam hydraulic intensifier, is required to work not with long and coniparatively slow pressing strokes but with a Succession of short and rapid strokes performed against the constant pressure of a cushion of live steam then maintained beneath the pistons in the pre'sshead liftingcylinders, it is necessary for the realization of the greatest economy in steam consumption that the preliminary or idle portion ofy each such short pressing stroke should be kept as small as possible Aby carefully a,djusting, from time to'time, what may be termed the Starting-position of the presshead and forging tool tosuit the gradually diminishing depth ofthe work, so that the tool, in the course'of a series of such strokes, may not be called upon to descend idly through a gradually increasing distance before it actually encounters the work. This adjustment, which involves admitting a vfurcharged during its entire working .stroke with steam-at a pressure sufficient to overcome the resistence encountered when the tool comes into `actual contact with the work, great waste of steam is liable to occur. The disadvantage becomes the more apparent in view of thefact that the intensifier steam piston is allowed to rise to that intermediate pointv in its Stroke whereat its further ascent becomesreifeetive for producing pressure upon the work', shortreversals of movement being effected Vabout this intermediate point for the purposeof producing the rapid finishing strokes of the presshead and tool, and the steam piston being seldom allowed to fall to its bottom position, so that specificati on of Letters Patent.

Patented Julyr 5, 1921.

Serial No. 279,395.

the Yentire space beneath the Steam piston has to be alternately opened to exhaust and re-charged with steam notwithstanding the relative shortness of the effective portion of each upward stroke.

The primary object of the present invention is to minimize this wasteful expenditure of steam, notwithstanding any neglect which may occur in adjusting the startingposition of the presshead and tool relatively to the work; for which purpose, according to the invention, each time the intensifier steam piston performs a downward or return movement, thelower end vof the steam cylinder is not opened to the exhaust as heretofore, but the opposite ends of theintensilier steam cylinder are put into communication with one another in a closed cir-` cuit so that, the steam which produced the previous upward or working stroke of the Y' main exhaust pipe and a passage connecting the delivery side of the primary exhaust valve with the upper end of the steam cyl'- inder of the intensifier, and in eans'for caus` ing this secondary exhaust valve to be opened and.. closed concurrently with the opening and closing of the steam inlet valve. 'Y As a result of the method of operation above described, when the intensifier steam piston begins each downward, or return movement, there will always exist beneath this piston steam at a reduced pressure dependent upon the position whence the piston descends, so that if the presshead has not been properly adjusted in the manner previously set forth) with a view to'economical working, the volume of steam beneath the piston will be saved because. in order to produce the next upward or working stroke of the intensifier, it will only be necessary to admit so much addi- .tional steam beneath the piston. as is neces- VVsary to restore therpressure to the amount re,v uired. Y Y

n addition to the saving'of steam thus ee'cted, a furtherV advantage is'obtained rovving to the fact that, as the time required l for establishing equilibrium of pressures on opposite sides of the intensifier steam ypiston is much less than that required for reducingy the steam beneath this piston to A atmospheric pressure (as With Y arrange:-`

ments 'at present in use) the intensifier v steampiston and attached parts Will descend Ymore promptly than heretofore rand will permit of the presshead beinglifted to Vraise the tool from the Work With correspondingly greater promptituder bythe action ofY the cushion of'live steam maintainedbeneath the pistons in Vthe presshead lifting-cylinders, While'the intensifier steam piston itself Y, vvilly have a greater tendency to remain near the lovver end of Y its strokefwvhich is the position best adapted forinsuring economical Working. A .Y

dIn a practical embodiment of the invenf tion asV applied to afsteam hydraulic intenl Ysifier constructed fin other respects substan# tially as describedin the s ecification of l the applicationV for Letters Jatent filedon 119thy January, 1918', Serial No. 212,550, the intensifier steam cylinder s provided, in ad; dition to thejusual upwardly-openingV steam inlet and exhaust valves adaptedto open in alternation With one another, .with a sec.- ond upwardly-opening exhaust valve placed beneath and in axial alinement with the steam inlet valve and attached to the inlet valvespindle so as to befopened and closed concurrently with the vopening and closing of the inletvalve itselfj'; the primary exhaust valve serving Yonly to control Vcomrnnniczugion between the lower'- endy of the intensifier steamqcylin'der and a branch kWhich leads from the upper end of the intensier steam cylinder to the space'abovethe secondary exhaust valve, While this latter exhaust valve controls communication between said branch and themain exhaust pipe. v Y .I 1n the accompanying drawings illustrat-- ing a convenient form of such an arrangement as applied to a hydraulic forging press constructed,substantially as descri led in the specification accompanying my application for Letters Patent filed 4th November, 11918, Serial No. 261,132, Figure 1 isa diagram- Vmaticl side elevationofthe steam hydraulic intensifier, whereof the steam Vand hydraulic cylinders are shown infaxial section, asV are` also the valves for controlling the steam connections appertaining to the steam cylinder of the intensifier and the lifting cylinders of the press. Figj2 is a similar side elevation of the hydraulic press operated bythe steam hydraulic intensifier illustrated in Fig. 1, the hydraulic cylinder and the Vtvvo lifting-cylinders of theV pressV being shown in axial section. Y I Y The ram 11 of the press (Fig.V reciprocates vertically jin the hydraulic cylinder l2`kand performs its Working strokes-in the downwardV direction; the ram 11 carrying at its'lower end the presshead 13, which is fittedfto Vslide onvertical rpillarsg14'rconnecting the Vtop Vplate or entablature 15, YWhereon the hydraulic cylinder'12 and the steamV lifting-cylinders 16 are mounted, with the base-plate 17 which supports the anvilY 18;V `r Ihe Work 19 is forged upon the anvil Y by the tool 20 carriedfby the presshead, the upward or'return strokes of the tool and press head being eifected by theadmission' of steam to the lifting cylinders 16beneath their pistons 21 which are.V connected to the presshead 13 by vertical piston-rods 22 fitted to lslide through stuiing-boxes L23 in the lower. ends of the cylinders 16. f Y rl`he hydraulicV mainfpressure pipe 24 conderV 12 of the press with the levierY end ,ofV the hydraulic `cylinder 25 lof the intensifier (Fig. 1) and thehydraulic,Working valve nects the upper end `of thehydrauliccylin- 26.. This valve26, which is interposedin`VVVY the vpipe 24 yand isadapted .to be operated by thehanding-lever. which controls` both the press and the intensifier, serves to governthe connection betvveenV the Vhydraulic main 24 andl the usuall air vessel 2S by Way of the hydraulic 'low pressure pipe v29 in the Well-- known mannerY of such apparatus. Y

The ram 30 of the intensifier reciprocates vertically Vin the hydraulic cylinder 25 and performs its Working stroke inthe upward direction; the ram 30 carryingat itsflovverV end 'a crosshead 31Which is coupledY by vertical Aside-rods 32 to the piston 33`of the steam cyl1nder'34 of the intensifier.V 4The Vhydraulic cylinder 25ofthe intensifier is placed beneath the Vsteam VcylinderV 34 andis fixed'at 35'lto thelovvermember cfa stool oropen frame. 36 the upper'member 37 ofV which is shown as constituting the bottomy Y ofthe steam cylinder 34; the side yrodsf'32,

Which are .guided at38 in the. lower member-j of the stool, passing through .stuffing-boxes 39 in the bottom 37 of the steam'cylinder.

The steam inletand-exhaust Yport 40 of v -the intensifier steam cylinder 34 is connected on'v the oneY hand with tliermain steam supply pipe..41 by Way of the steam inlet with the port 40 passing through the casing of 'the primary exhaustv valve 44 above the latter valve itself. TheV secondary exhaust valve 46 is placed' beneath and in axial alinement with the inlet valve 42 and is actuated -by the same spindle which actuates the inletvalve; while all three valves 42,44 and 46 are adapted for being controlled on the one hand manuallyA by meansof a single handing-lever 47, -and on therother hand automatically byv means: of hunting-gear adapted to cause the' supplyof steam to the cylinder 34 to becut olif, during each working stroke of the intensifier, at Ya point corresponding to the angular position wherein for the time being the handing-lever is held.

For the purpose of effecting the manual control of the valves, the handing-lever 47, which is fulcrumed ata xed point 47 a, has an arm 48 coupled by an kupright rod 49 yto the longer arm of what'may be termed the main lever 50 of vthe valve-actuating mechanism, this main lever 50, which is substantially horizontal, being fulcrumed at a fixed point 51 Vat a level'considerably above the valves. 52 is a floating lever 'which is connected by one end to the shorter arm of the main lever 50 and by the opposite end -to yan intermediate vpoint inthe upper section of an upright link 71 formed in two sections which are cou led together by a pinand-slot connection 1a, the lower end ot the lower section of this link being connected to the spindle 57 of the primary exhaustl valve 44; and 53 is a substantially horizontal rocking lever which is-fulcrumed at a -ixed point 54v beneath the level of the main lever 50 and floating lever 52; this rocking 'lever being coupled at one end to the spindle 5501c the steam inlet valve 42 and secondary exhaust valve 46 by a pin-and-slot connection 56, at the opposite end to an -in- -termediate point in the lower section of the Vwith a stationary `roller 63. Against the inclined edge 62 of this cam-bar, bears a roller 64 carried by one limb of a three-armed lever 65 which is fulcrumed at a iixed ,point V66, Contact between the roller and cam-bar .being insured by a counterweight 67 suspended from a second limb of the lever 65. A third limb of the same lever is coupled by an upright `rod 68 to one arm vof what may be termed .the secondary lever 69 (as distinguished from the main lever 50) of the valve-actuating mechanism; this secondary. lever 69,.whichis fulcrumed at a ixed point 70 above the `level of the floating :lever 52, having its other arm connected to the'upper end of the link 71 and thus to that end of the oating lever 52 which -is .remote from the main lever 50.

, In operation, each time the steam piston ,33 and hydraulic ram 30 of the intensifier are required to perform an upward or working stroke, the handing-lever 47 ismoved, from vthe mid or neutral position shown, toward the right so as to open the steam inlet valve42 and' admit live steam beneath the piston 33 inthe intensifier steam cylinder 34 ;4 this movement causing the secondary exhaust valve 46 to open as Well (While the primaryV exhaust valve 44 remains closed) so as to nput theupper end of the cylinder 34 into direct communication with the main :exhaust pipe 45Yby way of the pipe 431 and passage V43. When the piston 33 and ram 30 are subsequently required to perform a ldownward lor return stroke, the handinglever 47 is moved toward the left so as to close the steam inlet valve 42 'and open the 'primary exhaust valve 44; this movement causing the secondary exhaust valve 46 to close as well, so that the' steam beneath the piston 33. cannot pass to the main exhaust pipe 45 but is free to expand by way of the passage 43 and pipe 43a into the space above the piston. This expansion of the steam thus takes place in a closed circuit,

while the piston 33, hydraulic ram 30, and a'ttachedparts descend by gravity. Next time the steam inlet valve 42 is opened to bring about anV upward stroke of the piston 33 and ram 30,'the concurrent opening of the secondary exhaust valve46 permits the steam from 'above the piston 33 to be discharged into the main exhaust pipe 45,

. It is to be observed that when, during an upward or working stroke of the steam pis- -ton 33 and hydraulic ram 30 of the intensiylier, said piston and ram reach a level corresponding to the angular position in which vior the time being the handing-lever 47 is held, the action of the hunting-gear will cause the steam inlet valve 42 to close so that Ythe upward movement will be arrested and the piston and ram will be supported by the steam beneath the piston until, as the result of a subsequentmovement of the handinglever toward the left of its neutral position,

the primary exhaust valve 44' is opened so as .to 'permit of the expansion of the steam,

from beneath the piston 33 into the space 4above'the same as already stated.

From the foregoing, it will Vbe 'apparent that the sequence of steps 'in the different operations of my improved hydraulic intensier will be as follows Upon moving v farmi lever 47 to the right (to cause ya working stroke ofthe piston rod 49 will :be-,moved upward by armV 48, .thereby moving the longer arm ofV main lever 50 upward, and depressingthe shorter arm of said lever and with 4it the -end offloating lever 52 that is Vconnected thereto. l' Through the 'link 58 which connects the floating lever 52 with the f longer arm of the rocking lever 53, said arm will lbe depressed,y thereby elevating the shorter arm 'of lever 53, thereby raising the common spindle of valves 42 and 46 and thus inder 34, below piston 33,V and exhaustv steam opening-both of said valves, valve 44 meanwhile not beingmoved from its closed position. Live steam'will thereupon be admit- Vted through port 40 to the lower end of cylwillgpass from the upper end of the cylinder vthrough conduit 43a and into exhaustrpipe 45.- Vhen piston 33- has been moved upward al distance dependentuponlthe extent to' which lcv-er 47 has been moved to the i right, the vertical larm ofthree-armed lever i "65 will be moved to the left, :due to 'engagevnient of roller V64 thereon withthe inclined surface 62 of cam-bar 60, depressing the arm of secondary lever 69 which is connected by -r'od'68 with a horizontal arm of three-armed i .lever 65, and thereby elevating-the Vend of floating lever 52 which is connected withV the upper section of link 71. This will elevate VVthe longer arm of rocking lever 53, thereby `closing valves 42 and 46.A -Pinv 59 on the longer arm of rocking lever 53 Vwill meanvwhile move upward idly inl the slot in the lower section of link 71 andthe upper section Yof said link will telescopeon the lowerA section thereof, so that lvalve 44 will remain closed.I All three ofthe valves 42, 46 and44 asthus closed,and the piston 33 and ram"V 5 30 arev left supported bythe steam beneath Athe piston. To cause the piston to perform Ia downward or return stroke, k'hand-lever 47 is moved'to the left of its neutral position, which'-morvement, whilev leaving valves 42 and 46 inthe closed position,opens valve 44, whereby-the live steam beneath the piston enters the exhaustxsteamcontained in theV passageY between therear ofthe piston and the now closed exhaust pipe'45, since port 40 has' now an open connection with conduit 43,

43a, (and hence with'theV upper endo-f cylinder, 34)',v thus permitting equalization of the steam pressure on the two, sides of the piston.- The piston and ram 30V will now move downward by gravity until their descent is halted by moving hand-lever 47 Vto Y its neutral position, thereby closing the valve 44 and holding all three of the valves 42, 46

and44 in closed position, leaving the piston and the ram supported bythe exhaust steam below the piston. As is Vwell known, vthe piston in a device of this character when in use is seldom, if ever, allowed yto-proceed to the extreme end ofthe cylinder on its return steam to rthe working :stroke of the piston.

when, ascending, it

stroke, .but is stopped at jan intermediate pointfso'as to minimize itsdistanceof travel Y toward the work. .'Uponrthe closingof valve 44 the weight and-momentum of the piston Y -ac Y thereby reducing the amount Yoflive rsteam l required'for the working stroke, and only expanded exhaust-steam fromabove the:pisY f ton and in vconduit .435L1 vmust .bexexpelled 1throughexh'austl pipe f 45 as the Vworking stroke of the pistontakes place therebyV lessening the. oppositionV Voffered-.by said exhaust The .entirev manipulations required yof the operator are. of-.the simplesti nature and the apparatus is automaticinfaction, requiringonly that the workmanshall watch the workpiece on theanvil 'and-throw the1lever.47 when the tool 20 hasfdelivered its blowand piece. v v Y V.In the example illustrated, the .steam .connections toV the lifting-cylinders V16.*are controlled 'by a vertically-.working piston-valve 72 (hereinafter vreferred :to as the liftinghas. cleared the work- Y -lOO cylinder ivalve), .which is `actuated by the handing-lever 47. The casingofthe valve 72 has four sets. of ports at kdifferent levels ;V vthe `lowest set of ports 73 beingco-nnected by a branch 74 to the main steam supply pipe'4lV whilethe' .highest set lofports 7 5 are connected=bya pipe`76 tol-the 'main steam exhaust pipe 45.' Of the' two-intermediate sets of ports, the upper set 77 are connected by a Apipe78l and ,branches 79Y and 80 to the upper end of the respective lifting-cylinders'16;V Vwhile theV lower Vset 8l 'are connectedVV by a pipe Y82 Vand branches 83: and- 84to the lower end of therrespective lifting-cylinders.. The valve-pistonhas 'twocylindrical faces 85 and 86 .separated l by; a waist-portion/.87 of` reduced diameter; the lengths of the faces 85, 86, and their' distance apart, being suoli that,

so long as the valve-piston rests, asshown, in

its normalor lowest position, the ports'73 and 81 are. connected,togetheryand the ports 75 and V7 7 are also connected together but at the'same time separated from the portsv 73 and-8l, so that-n'thelone hand steamis ad-l mitted from the main steam supply pipeg4l (bywa-ylof the branch}74, ports 73 and 81, pipe `82,.and branch pipes 83 and Y84) tothe .lower ends ofthe:lifting-cylindersll, and

i 3ro on the other hand communication is opened from the upper ends of the cylinders 16 (by way of the branch pipes 79 land 80, pipe 7 8, ports 77 and 75, and branch pipe 76) to the main steam exhaust pipe 45; whereas, when 'valve-casing, is connected, throughl a combined telescopic joint and automatically-acting detent-and-trip mechanism of known construction indicated at 90, with a rod 89 permanently attached to the main lever 50. t

vSo long as the handing-lever 47, main lever 50, and piston- valve 85, 86, 87 occupy substantially the position shown, the telescopic joint permits free movement of the rod 89 relatively to the valve-spindle 88 in either direction within predetermined limits, but when the handing-lever 47 is angularly displaced toward the leftso as to depress thelever 50 and rod 89- beyond a certain limit, the valve-spindle 88 becomes automatically engaged with the rod 89 and hence, when the handing-lever is returned toward the right, the valve- piston 85, 86, 87 is raised along with the lever 50 until, on the valvepiston passing upward beyond the intermediate positionalready referred to, the valve spindle 88 becomes automatically disengaged from the rod 89 so that the valvepiston is free to fall back to its lowest position. A y

From the foregoin it will be seen, first, that so long as the va ve-piston 85, 86, 87 is in its normal or lowest position, a cushion of high-pressure steam will be maintained in the lifting-cylinders 16 beneath the pistons 21 which will accordingly (assuming other conditions tobe favorable) tend to rise and lift the presshead 13 and ram 11,' owing to the absence of steam pressure above the pistons 21 in consequence of the upper ends ofthe cylinders 16 being open to the exhaust pipe; secondly, that when the valvepiston is raised from-the lowest to the intermediate position, high-pressure steam will 11o-longer be able to gain access to the cylinders 16 beneath the pistons 21, while the steam already beneath these pistons will be allowed to pass from the lower to the upper side of the pistons and will expand until, equilibrium of pressures being established on the opposite sides of the lifting-pistons, the presshead 13 and ram 11 (if previously raised) will be free to descend under grav- Y ity; and thirdly, that the valve-piston, when further raised to the level at which it is released from the lever 50, will automatically return to the lowest position, thus restoring the cushion of high-pressure steam beneath the lifting-pistons 21 while allowing the expanded steam above said piston to become exhausted so that (other conditions being favorable) the presshead 13 and ram 11 will again tend to rise.

The working-valve 26, the construction and operation of which are fully described in the specification the application for Patent No. 212,550, already referred to, is controlled (as previously stated) by the handing-lever 47; for which purpose the arm 48 of the handing-lever is coupled by a rod 91 to a lever 92 which acts upon the spindle of theworking-valve.. This valve, which normally cuts off communication between the air vessel 28 and the hydraulic main pressure pipe 24, is adapted, when open, to permit water to flow from the pipe p 24 tothe air vessel or vice versa according to circumstances the opening of the valve being produced by means of the handing-lever 47 when it is required to reduce the quantity of water in the pipe 24 and cylinders 11 and 25, but being effected automatically when it is required to fill up the vacuum created in the pipe 24 and cylinders 11 and 25 by the idle descent of the rams 11 and 30 or either of them.

In the foregoing description, the elastic motive fluid operating in thel intensifier and in the lifting-cylinders of the hydraulic press is for the sake of convenience referred to as steam, but it will be evident that other elastic motive iiuid (such as compressed air for example) may be used; and hence it is to be understood that both throughout the description and in the appended claims the term steam.is to be interpreted as including any kind of elastic motive fluid. Y

Having now particularly described and ascertained the nature ofmy said invention and in what manner the same is to be performed, l declare that what I claim is 1. A steam hydraulic intensifier comprising ka steam cylinder, a piston movable therein, hydraulic means connected with said piston, an inlet for live steam to said cylinder, an exhaust outlet therefrom, a steam connection between opposite ends of said cylinder, whereby the steam pressure upon opposite sides of said piston is equalized during the return stroke thereof, and means for compressing exhaust' steam on the working side of said piston during completion of the return stroke thereof, whereby such com- 2. A steam hydraulic intensifier comprising a steam cylinder, a piston movable therein, hydraulic means 4connected with said piston, an inlet for live steam to said cylinder, an exhaust outlet therefrom, a steam connection between opposite ends of said cylinder, whereby the steam pressure upon opposite sides of said piston is equalized during the return stroke thereof, and means for expanding the steam on the idle side of said piston during completion of the return stroke thereof, and thereby lessening the opposition offered by said steam to the next working stroke of the piston. i

Y 3. A steam hydraulic intensifier comprising a steam cylinder, a piston movable therein, hydraulic means connected with said piston, an inlet for live steam to said cylinder, an exhaust outlet therefrom, a steam connection between opposite ends of said cylinder, whereby the steam pressure upon opposite sides of said piston is equalized during the return stroke thereof, and means for compressing exhaust steam on the working sidev of said piston during completion of the return stroke thereof while expanding the steam on the idle side of said piston during the completion of vthe return stroke, whereby such compressed exhaust steam is met by the live steam admitted tothe cylindercfor the next working stroke while the opposition offered by the exhaust steam tov said'next working stroke is lessened.V

- 4c. ln a steam hydraulic intensifier', Athe combination of a steam cylinder, a piston movable therein, hydraulic means connected with said piston, an inlet for admission of live steam to said cylinder to effect movement of said piston on the working stroke, a steam connectionbetween the opposite ends of said cylinder, means for closing said connection prior to initiating the working stroke of said piston and for opening'it during the return stroke, whereby during such return stroke exhaust steam has access to the idle side of said piston, and steam at a pressure at least equal to said equalized pressure is interposed between the piston and the live steam admitted to effect the next succeeding working stroke and coperates therewith, and an exhaust for the spent steam from said cylinder open during the working stroke of the piston.

5. In a steam hydraulic intensifier the combination of a steam cylinder, a piston movable therein, hydraulic means connected with said piston,l a conduit connecting the cylinder on opposite sides of said piston, an exhaust connection communicating with said conduit, a steam inlet to one end of the cylinder, valves to control the steam inlet, the conduit and the exhaust, and means for controlling said valves to close the valve in the conduit prior tothe opening ofthe steam inlet and exhaust valves and to open the conduit valve subsequent to the closing of the steam inlet and exhaust valves, whereby the full volume of steam employed during thepower stroke is retained in the sys- 'tem represented by the two sides of the piston and the conduit between them during the return stroke, and the maximum quantity of steam is conserved on the power side of the piston at the time when live steam is againy admitted to said side thereof.

6. rllhe'combination of an upwardly-acting steam hydraulic intensifier including an upright steam cylinder, a piston movable vertically therein, an inlet for the power fluid at the lower part of said cylinder to elevate the piston on the working stroke, a conduit connecting the opposite ends of said cylinder means for closing said conduit during the working stroke of the piston and for opening` it during its return stroke whereby during said return stroke steam pressure upon opposite -sides of said piston is equalized, permitting the return stroke of the piston to be influenced by gravity, means for establishing a cushion of steam at a pressure at least equalato said equalized pressure below the piston in position to coperate with lthe live steam in effecting the next succeeding working stroke, an exhaust connected with said conduit, valves controlling said conduit, said inlet and said exhaust and means for operating said valves in coordination with each other. f V

7. The combination of a hydraulic press, an upwardly-actii'ig steam hydraulic intensifier structurally independent of said press and connected therewith, said intensier including an upright steam cylinder and a piston vertically movable therein, an inlet for the power iiuid at thev lower part of said cylinder to elevate the piston von the workingstroke, a valve in said inlet, a conduit connecting the opposite ends of said cylinder, means for closing said conduit during the working stroke of the piston and for opening it during its return stroke, whereby during said return stroke steam pressure upon opposite sides of said piston is equalized, permitting the return stroke of the piston to be influenced by gravity, means for maintaining a cushion of steamv at not less than said equalized pressure between the steam inlet valve and the lower surface of the piston until the next succeeding working stroke, a steam inlet connected with said conduit, an exhaust connected with said conduit,

an exhaust valve controlling said exhaust, an additional exhaust `valve controlling said conduit and means for operating the additional' exhaust valve concurrently withthe operation of the steam inlet valve.

8. lin a steam intensifier the combination of a steam cylinder, a piston movable therein, hydraulic means, connection between the said hydraulic means and said piston, said connection operating to reduce the pressure area of the piston on that side thereof receiving the working force of the steam, a conduit connecting the cylinder on opposite sides of said piston7 means for closing said conduit during the working stroke of the piston and for opening it during the return stroke thereof whereby during said return stroke steam pressure upon opposite sides 10 of said piston is equalized, -a steam inlet whereby live .steam is admitted to one end of the cylinder and added to steam at not less than said equalized pressure to effect the working of the piston and a vent connected with said conduit and arranged to open during the working stroke wherebT the steam previously conducted to said opposite side of the piston is exhausted during said working stroke.

THOMAS WILTON HAND. l

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