US3893790A - Dual single action ram intensifier - Google Patents

Abstract

A ram type intensifier capable of producing a continuous flow of liquid at pressures on the order of 70,000 psi is disclosed, comprised of a pair of alternately and cyclically stroked ram cylinders, in which the flow of pressurized operating fluid to the ram chambers is from a constant pressure source controlled such that simultaneous pressurization of both ram chambers is provided at the end of each cycle so that precompression of the cylinder beginning its pressure stroke is carried out before depressurization of the cylinder ending its pressure stroke. This arrangement prevents pressure variations occurring as a result of the substantial compression of the liquid occurring at these pressure levels.

Description

United States Patent 1191 Mayer July 8, 1975 [54] DUAL SINGLE ACTION RAM INTENSIFIER 3,331,329 7/1967 Bauer 417/342 3,381,833 5/l968 Gordon 60/97 E [751 Inventor: 5 9 May", B'mmgham- 3,638,424 2/1972 Valantin 60/371 [73] Assignee: The Bendix Corporation, Southfield, Primary Examiner-William L. Fleeh Mich. Assistant Examiner-Gregory P. LaPointe Filed y 29 1973 Attorney, Agent, or Firm.|ohn R. Benefiel [2|] Appl. No.: 364,595 [57] ABSTRACT Rented Application Data A ram type intensifier capable of producing a continu- [63] Continuation-impart of Ser. No 139 098 April 30 l r of liquid at pressures on the Order of 70'000 197 abandoned ps1 15 disclosed, comprised of a pair of alternately and cyclically stroked ram cylinders, in which the flow of 52 us. 01 417/346- 60/371 Pressurized Warming fluid the ram chambers is [51] ML F041; l7/0o b 31/02 from a constant pressure source controlled such that [58] Field 0 Search 417/225 344447 simultaneous pressurization of both ram chambers is 417/342, 60/197 371 provided at the end of each cycle so that precompression of the cylinder beginning its pressure stroke is [56] References Chad carried out before depressurization of the cylinder ending its pressure stroke. This arrangement prevents UNITED STATES PATENTS pressure variations occurring as a result of the sub 2,442,916 6/1948 Buchanan 417/346 t j compression of the liquid Occurring at these 2,508,298 5/1950 Saari i i 417/225 pressure levels 2,579,670 l2/l95l Hjarpe 417/225 2,858,767 11/1958 Smith 417/346 1 Claim, 9 Drawing Figures SHEET EUT L 8 i975 INVENTOR ENDRE A. MAYER BY ATTORNEY FFETF? HTML 8 ms SHEET 7?) STdRTuP VALVE M F v w .|||||||/\.l|||

z w p m I I I 0 lull INVENTOR FIG-4 ENDRE A. MAYER ATTORNEY ZliTEUTEMUL 81975 3.893.790

SHEET 3 6 202 FIG 5 lNVENTOR ENDRE A. MAYER ATTORNEY 1 DUAL SINGLE ACTION RAM INTENSIFIER CROSS REFERENCE TO RELATED APPLICATIONS now abandoned.

BACKGROUND OF THE INVENTION l. Field of the Invention This invention concerns intensifiers and particularly ram type intensifiers capable of producing pressures of 70,000-l 00,000 psi.

2. Description of the Prior Art Fluid Jet cutting in which a high pressure liquid jet is used to cut various materials, has long been proposed and demonstrated experimentally. However, practical industrial application of this concept has heretofore been precluded because of several technical difficulties, one of which being the problem of providing a suitable source of high pressure liquid.

This is a difficult problem since pressures in excess of 30,000 psi are generally required and most such applications would call for pressures on the order of 50-70,000 psi or even higher, and liquid under these pressures must be supplied continuously in order to yield clean cuts of the workpiece.

Furthermore, in many situations the jet assembly must be moved over the workpiece, such as in automated pattern cutting, and since flexible hydraulic lines and couplings are not available which are capable of handling such pressures, a source which is reasonable in size and weight is highly desirable.

Heretofore, the only commercially available systems for continuously producing a flow of liquid under pressures on this order have been double acting differential piston type ram intensifiers, as for example that disclosed in US. Pat. No. 2,631,542.

This approach has not been very successful since the deflections tending to occur at these very high pressure levels are particularly troublesome in this device as three-point" support is involved and the parts must be designed to be very large and stiff to prevent binding of the parts during stroking. Furthermore, the ram tends to be excessively long and bulky since the chambers are arranged end-to-end.

These deflections also tend to aggravate the piston sealing problems and the heavy construction requires considerable seal servicing effort and consequent excessive downtime.

A prior art intensifier as described in US. Pat. No. 2,579,670 to Hjarpe discloses a dual free piston intensifier which arrangement would alleviate some of the difficulties described above, but the valving arrangement disclosed in that patent does not provide simultaneous pressurization of the separate cylinders sufficient to precompress the liquid in the cylinder beginning its pressure stroke.

Another prior art intensifier described in US. Pat. No. 3,33 l ,329 to Bauer describes such a single acting twin cylinder intensifier which does involve overlap or simultaneous pressurization of both cylinders at the end of both cylinders at the end of each cycle to alleviate pressure surges occurring because of the transition conditions existing during the changeover of the load from one to the other cylinder. However, as stated therein, this system is designed for pressures in which compression of the liquid is negligible. Specifically, the fluid which operates the rams is supplied from a constant volume source. This type of source would not function in the environment of the extremely high pressures causing substantial compression of the working fluid since the compression of the liquid would create a substantial drop in pressure in the ram chambers, in turn causing a substantial drop in the output pressure to thereby defeat the purpose of the overlap.

It has been discovered by the present inventor that a great deal of compression of working liquids which are considered incompressible is encountered which would severely hinder the production ofa continuous flow of liquid at these higher pressures with the arrangement described in the aforementioned patents since compression of the liquid would take place for a substantial portion of the pressurization stroke of each cycle and hence the maximum pressure thereof would not be developed during this portion of the stroke.

Therefore, it is an object of the present invention to provide an intensifier which is relatively lightweight and compace and yet capable of providing a continuous flow of liquid at pressures on the order of 70,000

psi.

SUMMARY OF THE INVENTION This object and others which will become apparent upon a reading of the following specification and claims is accomplished by providing a dual single action ram type intensifier which is controlled so that during a portion of each compression stroke of each piston the other piston is fully pressurized to create a substantial overlap in the operation. The return stroke of each piston is powered by the working liquid which is supplied thereto under sufficient pressure to minimize the effects of air bubbles on the volumetric efficiency of the intensifier and on the continuity of flow, as well as to eliminate the need for an arrangement to create return strokes thereof by the operating fluid.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic representation of the dual single action ram intensifier arrangement together with its as sociated valving and hydraulic circuitry.

FIG. 2 is a schematic representation of the dual pistons and their associated valving at an intermediate stage of the intensifier cycle.

FIG. 3 is a schematic representation of the dual pistons and their associated valving at an advanced state of the intensifier cycle.

FIG. 4 is a schematic representation of the start-up valve and the control valves during initiation of the intensifier operation.

FIG. 5 is a front elevational view of a specific embodiment of the dual piston intensifier assembly.

FIG. 6 is a view of the intensifier assembly in the direction of the arrow 6-6 in FIG. 5.

FIG. 7 is a view of the section taken along the line 7-7 in FIG. 5.

FIG. 8 is a view of the intensifier in the direction of the arrow 8-8 in FIG. 5.

FIG. 9 is a schematic representation of a second embodiment of the dual single action ram intensifier according to the present invention.

DETAILED DESCRIPTION In the following detailed description, certain specific terminology will be utilized for the sake of clarity and a specific embodiment described in order to provide a complete understanding of the invention, but the invention is not so limited and may be practiced in a variety of forms and embodiments.

Referring to the Figures and particularly FIG. 1, the intensifier of the present invention includes first and second single action ram intensifier means and 12 controlled by a pair of associated pilot pressure operated control valves 14 and 16.

Each ram intensifier cylinder 10 and 12 includes a respective piston member 18 and 20 disposed in a respective cylinder means 22, 24. The piston members consist of connected large diameter heads 26 and 28 and smaller diameter heads 30 and 32 which together with the cylinder means define in upper chambers 34, 36 and lower chambers 38 and 40 in the cylinder means 22 and 24.

This arrangement constitutes the basic intensifying apparatus, with a lower pressure fluid introduced in each upper chamber 34 and 36 which, acting on the pistons 18 and 20, serves to raise the pressure of a working liquid introduced to the lower chambers 38 and 40 by virtue of the difference in area of the con nected piston heads.

For example, in one design a large diameter head of 2.50 inches diameter and a small diameter head of 0.625 inches diameter was used to create an intensification ratio of 18 to l. Thus, using a 5000 psi supply in the upper chambers, a 70.000 psi pressurization of the working liquid can be obtained.

The supply operating fluid under pressure to each upper chamber is provided by means of conduits 42, 44 disposed entering the top of each cylinder 22 and 24 so as to pressurize the volume above each large diameter head 26 and 28.

A source of operating fluid 46 is provided such as a 5000 psi oil pump which may include an accumulator 48, and its communication with the conduits 42, 44 is controlled by the pilot pressure operated control valves 14 and 16, respectively.

This source 46 and the associated accumulator 48 must provide a means for supplying fluid under pressure to the upper chambers 34 and 36 at a substantially constant pressure over the range of flow requirements encountered during the operating cycle. This is particularly important during the overlap portion of the cycle to be described in detail herein, since the pressurization of the cylinder upper chamber at the beginning of its pressure stroke involves a rather rapid increase in the volume of the upper chamber due to compression of the working fluid. This resulting large momentary flow must be provided by the source 46 without causing a substantial pressure drop in the chamber of the cylinder approaching the end of its pressure stroke lest a corresponding drop in output pressure occur.

Each control valve 14 and 16 includes a valve spool 50, 52 slidably disposed in a valve bore 54, 56, respectively.

The valve spools 50 and 52 by means of their position in each bore 54, 56 control communication between ports 58, 60, and 62, 64 with ports 66, 68, respectively, hence providing a three-way function of the valves 14 and 16.

Ports S8 and 60 are connected via conduits 70, 72 with the source 46, while ports 62, 64 are connected to the sump 74 via conduits 76, 78, and 80. Ports 66 and 68 are connected to the conduits 42 and 44, respectively.

Thus, in the position of the valve spool 50, shown in FIG. 1, the region of upper chamber 34 of cylinder 22 above the large diameter head is connected to the sump 74 as port 58 is blocked by the land 82, while in the position of the valve spool 52 shown therein, the upper chamber 36 of cylinder 24 above the large diameter head 28 is connected to the source 46 as the land 84 blocks the port 64. In the opposite positions of the valve spools, the opposite would be true. as the land 86 would block the port 62, while the land 88 would block the port 60.

The position of each of the valve spools 50 and 52 in their respective bores 54 and 56 is controlled by pilot pressures applied to opposite ends 90, 92 and 94, 96 thereof, with these pilot pressures being generated by movement of the pistons 18 and 20 in the cylinders 22 and 24. This is accomplished by means of sensing lines 98, 100 and 102, 104 communicating with chambers 106, 108, 110, and 112, respectively, each being behind a respective valve spool end 90, 92, 94, and 96.

Sensing line 98 is connected to a sensing port 114 positioned in cylinder 22 so that in the full down position of piston 18, it will be uncovered and direct source 46 pressure to chamber 106. Sensing line 100 is connected to port 116 positioned in cylinder 24 so that as the piston 20 moves downwardly at an intermediate point in its pressurization travel, port 116 will be uncovered and direct source pressure to chamber 108. Sensing line 102 is connected to sensing port 118 positioned in cylinder 22 so that in a similar manner, at an intermediate point in the downward travel of the piston 18, the port 118 will be uncovered and direct source pressure to chamber 108. Sensing line 104 is connected to sensing port 120 positioned in cylinder 20 so that at the full down point in travel of the piston 28 it likewise is uncovered to direct source pressure to chamber 110.

In order to maintain the spools 50, 52 in the positions created by the application of the pilot pressures, mechanical detents 122 and 124 may be provided. Alternate approaches such as hydraulic lock of the chambers 106, 108, 110, and 112 or magnetic detents described infra could be utilized.

in order to insure proper synchronization of the pistons l8 and 20 during start up, a start-up valve 126 is provided which serves to momentarily pressurize conduits 128 and 130 and cause the valve spools 50, 52 to be positioned in a manner to be described more complete infra, while normally these conduits are connected to the sump 74 via conduit 132 as shown in FIG. 1 and do not affect the operation of the device.

The source 134 of working liquid provides a means for supply of the working liquid to each of the lower chambers 38 and 40 via conduits 136 and 138, check valves 140 and 142, and conduits 144 and 146. For many cutting applications water is preferable as a cut ting fluid and the system will be described as such. Since oil is the preferred liquid for hydraulic systems as the intensifier arrangement of the present invention, a two-liquid system results. The water is supplied under relatively high pressure, i.e., 3000 psi for the system described as contrasted with prior art intensifiers utilizing differing operating and working fluids for the abovedescribed reason which have supplied the working fluid under substantially no pressure, and have relied on the operating fluid to provide the return stroke.

This approach minimizes the effects of bubbles in the working liquid source 134 on the volumetric efficiency of the system as their volume is much reduced initially. In addition, this eliminates the need for a separate return cycle arrangement with the operating liquid. as the high pressure working liquid provides a means for re- I turning the pistons to their return position after a pressurization cycle since it forces each of the pistons upwardly whenever the operating fluid is not applied to their respective upper chambers 34 and 36.

The working liquid, during the compression stroke of each piston 18, is directed to a common outlet means comprising the utilization device, such as the fluid jet cutting system 148 described via check valves I50, I52 and conduits I54, I56, and I58. Thus alternating and overlapping pressurization of the cylinders will cause the liquid under high pressure to be directed to the fluid jet cutting system. From this description it can be appreciated that check valves I50 and 152 prevent communication of the lower chambers 38 and 40 with the common outlet means except when these chambers are pressurized.

The fluid jet cutting system may include a surge vessel 160 and a nozzle 162 of a construction as described in copending application Ser. No. 119,758, filed Mar. 1, I971, Nozzle for Producing Fluid Cutting Jet, M. C. Kurko et al.

By reference to FIGS. 2 and 3, the operation of this device after start up may be readily understood. Assuming that the intensifier is pressurized in the manner depicted in FIG. 1, ie. the upper chamber 36 of cylinder 24 is pressurized and the upper chamber 34 of cylinder 22 connected to the sump, the associated piston 20 will move downwardly, pressurizing the liquid in the lower chamber 40.

when the piston 20 has reached the point intermediate in its pressurization travel depicted in FIG. 2, the sensing port 116 will be uncovered and pressurized by the operating fluid under pressure. This pressure acting via sensor line 100 in chamber 92 will force valve spool 50 to the left as viewed in FIG. 2 to the position depicted therein, which will serve as means to cause pressurization of the upper chamber 34 associated with returned piston 18 via conduit 42.

This pressurization will cause the piston 18 to move to compress the working liquid in the lower chamber 38, while at the same time the pressurization of the upper chamber 36 is maintained substantially unabated.

Thus, preceding the return movement of piston 20, both pistons 18 and 20 will then be pressurized and move downwardly together (although more slowly than piston 20 alone) until the piston 20 reaches the point depicted in FIG. 3, at which point the sensing port 120 is uncovered. The resulting pressurization of sensor line I04 and connected chamber 110 causes the valve spool 52 to shift to the right to the position depicted in FIG. 3, which in turn causes chamber 36 to be connected to the sump 74 and piston 20 to the return position.

In the meantime, piston 18 has descended to the position depicted in FIG. 3 to provide substantially full pressurization and continues to descend, thus maintaining the output pressure.

The amount of overlap is designed so that all compression of the liquid, conduits, etc., has taken place at the beginning of each pressurization cycle and the pressure of the working liquid compressed by intensifier cylinder I0 has risen to the operating pressure of the device before the depressurization of intensifier cylinder 12, so that no fluctuations of the output flow or pressure is encountered.

It has been determined by the present inventor that the degree of overlap necessary at pressures on the order indicated, i.e., 70,000 psi. is considerable since substantial travel of the piston at the beginning of its pressure strike must take place to precompress" the working liquid in the lower chamber before reducing the pressure in the cylinder ending the pressure stroke.

For example. in the system described and with a three-inch stroke, the sensor ports H6 and I20 of intensifier cylinder 12 and H4 and 118 of intensifier cyl inder It) would be positioned 0.5 inches apart and the resulting compression" travel would be on the order of 1.0 inches in order to minimize such pressure variations.

Piston 18 then continues downwardly (although more rapidly) until port 118 is uncovered causing pressurization of sensor line 104 and chamber 112, causing intensifier cylinder 12 to be turned on once again in a similar manner as with the cycle of piston 20. When piston 18 reaches bottom and port H4 is uncovered, sensor line 98 and chamber 106 are pressurized causing intensifier 10 to be turned off, and piston 8 to be re turned to the return position.

Thus, the cycle repeats itself over and over as long as an operating fluid is supplied thereto. For the specific system described a cycle rate of 3.65 Hz has been calculated to produce an output flow rate of l gpm at 70,000 psi.

By referring to FIG. 4, the operation of the start-up valve 126 may be understood. In the position shown, the start-up valve spool 164 directs via conduit 166 and port 167 fluid under pressure from source 46 to chambers I68 and 170 of control valves 14 and [6 via port I71, conduits 172 and 174. This causes free pistons I76 and 178 to force valve spools 50 and 52 into the position shown in FIG. 4 to properly synchronize their operation. Valve spool I64 stays in this position only momentarily until pressure builds up in conduit 180 and chamber I82 to cause the valve spool I64 to move to the right as viewed therein against the bias of a spring 184 to the position shown in FIG. 1. Land 186 then blocks port I67 while land I88 moves to uncover port 190 and place conduits 172 and 174 in communication with the sump 74 via branch conduit I92.

The response of the valve spool I64 is controlled by an orifice 194 and accumulator 196 so that its movement is delayed until the valve spools 50 and 52 have shifted. Alternatively, an electronic operator and delay or other arrangements could be used to provide this function.

This arrangement insures that the valve spools are in the proper position at the beginning of operation to initiate the cycling activity.

Also, in connection with start-up, flow into the supply chambers must be limited sufficiently so that too rapid descent of the pistons does not occur since they encounter relatively little resistance until the output load builds up, which in turn can cause a loss of of synchronization if the return stroke of the piston I8 is not completed before piston 20 reaches port 116 and thus initiates a premature power stroke of piston 18.

To accomplish this end, flow limiting orifices I98 and 200 can be incorporated in conduits 70, 72 or the associated ports could merely be properly sized to limit the maximum flow.

Referring to FIGS. -8 a specific hardware embodiment of the present invention is depicted.

This includes a pair of intensifier cylinders 202, 204 in side by side relationship held together by means of a top manifold plate 206, intermediate manifold plate 208, and bottom manifold plate 210, which in turn are held together by sets of studs 212 and 214.

Each intensifier cylinder 202 and 204 includes a control valve assembly 216 and 218, while a start-up valve 220 is mounted therebetween.

An accumulator 222 corresponding to the accumulator 48 depicted schematically in FIG. 1 may be mounted between and below the intensifier cylinders 202 and 204, and in communication with conduit 224 and passages (not shown) in the top manifold plate 206.

FIG. 7 shows intensifier cylinder 204 and its associated control valve 218 in section, which is typical of both intensifier cylinders 202 and 204. This includes a piston 226 having a large diameter upper head 228 s1idably disposed in an upper cylinder 230, connected by a self-aligning coupling 231 to a smaller diameter lower head 232 passing through intermediate manifold plate 208 and disposed in a lower cylinder 234.

The upper cylinder 230 includes an outer load bearing sleeve 236 and an inner wear sleeve 238, which has the sensor ports formed therein with the lower shut-off sensor port 240 shown both which are preferably shaped as a narrow slit. This form of sensor port reduces seal scuffing and abrasion as the piston 226 tra V verses the inner sleeve 238.

Each sensor port communicates with openings (not shown) in the outer sleeve 238 in turn connected to sensor lines 242 and 244.

The piston 228 is cushioned at the top of cylinder 230 by a spring washer stop 246 and at the bottom by a resilient ring 248.

The bottom cylinder 234 includes an outer sleeve 2S0 stretched over an inner sleeve 252 so as to preload the inner sleeve 252 against the pressure loading. This has been found to be an efficient cylinder design for withstanding very high pressures.

The dynamic sealing of the small diameter head 232 during the compression stroke is accomplished in this embodiment by means of a controlled leakage bushing 254. This arrangement, which has been described in the literature, creates a seal under high pressure con ditions by creating a pressure differential across the sleeve 2S6. Liquid which gets past the packing 2S8 flows into both clearance 260 and the space between the small diameter head 232 and the sleeve. Since clearance 260 ends in a static packing 262, the liquid is trapped, while flow past the small diameter head 232 is allowed to escape and be collected by annular slot 264, passage 266 and line 268. Thus, during the compression stroke a pressure differential across the sleeve 256 is created which causes the sleeve 256 to grip the small diameter head tightly, but during the return stroke to allow free movement therethrough.

The control valve 218 includes a valve spool 270 slidably disposed in a bore 272 and positioned by means of pilot pistons 274, 276, and 278. Valve spool 270 controls the communication of passage 280 and port 281 connected with the return line 282 and connected passages 284, 286, and 288 and the supply line 224 and connected passage 290, by either blocking port 292 or 294 depending on its position in bore 272.

Pilot piston 274 is operated by pressure received from sensor port 240 and sensor line 244, pilot piston 276 is operated by pressure received via sensor line 296 connected to the on sensor port of the opposite intensifier cylinder 202, while piston 278 is operated by pressure received via line 298 from the start-up valve 220 (FIG. 6).

A pair of permanent magnets 300, 302 are utilized to provide the detent function, holding the valve spool 270 in one position or the other by magnetic attraction therebetween until overcome by the pilot pistons.

Leakage flow past the pilot pistons 274, 276, and 278 is collected via relieved areas 304, 306 at each end of the bore 272, and ports 294 and 308, and passages 310 and 288, and passed into the return passages 286, 284.

In order to collect any leakage flow past the large diameter head 228 and from the sensor ports, as well as to allow return flow to fill the space behind the large diameter head 228 during the return strike, a line 312 communicating with passage 314 in turn communicating with annular passage 316 and opening 318 is provided.

Thus, as the operating fluid is displaced from above the head 228 during the return, it may readily flow via port 294, passages 288, 286, 284 into line 312 and passages 314, 316, and 318 into the area behind the head, thus minimizing the resistance during the return stroke.

The working liquid is supplied via line 320 inlet check valve 322, and enters the lower cylinder 234 via passages 324, 326. During the compression stroke, flow passes into passages 326, 328 past outlet check valve 330 into slot 332, passage 340 (FIG. 8) to the output passage 342. The fluid jet cutting nozzle assembly could be threaded directly into the passage 342 to receive the output flow.

This specific embodiment operates as described in reference to the schematic drawings of FIGS. l5.

In the embodiment described in FIGS. 1-5, sequencing difficulties may occur due to unequal pressures generated in the lower chambers from the same applied pressures in the upper chambers 34 and 36 if significant manufacturing variations result in differing piston areas, differences in friction, etc. This difference in lower chamber pressure could cause arresting of the motion of the piston approaching the end of its pressure stroke before it has uncovered the final ports 114 or 120.

The alternate embodiment shown in FIG. 9 obviates this potential difficulty by modifying the means for generating the shut off signal. in this embodiment the shutoff signal is generated from ports 344 and 346 in cylinders 10 and 12 respectively, these ports being located at a level such that the pistons 18 or 20 will have carried out their precompression at the point at which these ports are uncovered. These ports 344 and 346 are connected via lines 348 and 350 to chambers 106 and 112 of valves 14 and 16 so that the piston which is approaching the end of its cycle is turned off when the other piston has moved sufficiently to uncover its sensing port 344 or 346. Thus, the aforementioned lock up cannot occur, since even if the piston would be arrested in its motion, as the piston starting up reaches full pressure sequencing will proceed since it does not depend on further travel of the piston at the end of its stroke.

While specific embodiments have been described, the invention is not to be so limited and many varia- 9 tions are of course possible within the scope of the present invention.

l claim:

1. A fluid actuated intensifier comprising:

first ram intensifier means including a piston member disposed in a cylinder means to form an upper chamber defined by said cylinder means and one head of said piston and a lower chamber defined by the other head of said piston and said cylinder means;

second ram intensifier means including a piston member disposed in a cylinder means to form an upper chamber defined by said cylinder means and one head of said piston and a lower chamber defined by the other head of said piston and said cylinder means;

means for introducing fluid into said lower chambers;

means for pressurizing said upper chambers including a constant pressure source capable of supplying said fluid to said upper chambers without a substantial drop in pressure due to substantial flow into said upper chambers resulting from compression of said fluid in said lower chambers;

said means for pressurizing said upper chambers also including control means cyclically pressurizing said upper chambers by communication with said constant pressure source so as to cause said piston members to alternately move to pressurize said fluid introduced into said lower chambers and including means causing each of said pistons to move to a return position after said pressurization cycle, said control means further including means causing simultaneous pressurization of both of said upper chambers and means causing both piston members to simultaneously move to pressurize said lower chambers preceding the return movement of either of said piston members by said simultaneous pressurization, said control means including a pair of control valve means operatively associated with each of said ram intensifiers operable indepen' dently of each other to produce said simultaneous pressurization of said rarn intensifier means. and further including start-up valve means causing said control valves to momentarily pressurize one of said upper chambers and depressurize the other of said upper chambers during start-up of said intensi fier, whereby said piston members initially assume oppositive positions in said cylinder means;

common outlet means receiving fluid pressurized in said lower chambers, including means providing communications of said lower chamber with said common outlet means during said pressurization and discontinuing communication during said return movement.

Claims (1)

1. A fluid actuated intensifier comprising: first ram intensifier means including a piston member disposed in a cylinder means to form an upper chamber defined by said cylinder means and one head of said piston and a lower chamber defined by the other head of said piston and said cylinder means; second ram intensifier means including a piston member disposed in a cylinder means to form an upper chamber defined by said cylinder means and one head of said piston and a lower chamber defined by the other head of said piston and said cylinder means; means for introducing fluid into said lower chambers; means for pressurizing said upper chambers including a constant pressure source capable of supplying said fluid to said upper chambers without a substantial drop in pressure due to substantial flow into said upper chambers resulting from compression of said fluid in said lower chambers; said means for pressurizing said upper chambers also including control means cyclically pressurizing said upper chambers by communication with said constant pressure source so as to cause said piston members to alternately move to pressurize said fluid introduced into said lower chambers and including means causing each of said pistons to move to a return position after said pressurization cycle, said control means further including means causing simultaneous pressurization of both of said upper chambers and means causing both piston members to simultaneously move to pressurize said lower chambers preceding the return movement of either of said piston members by said simultaneous pressurization, said control means including a pair of control valve means operatively associated with each of said ram intensifiers operable independently of each other to produce said simultaneous pressurization of said ram intensifier means, and further including start-up valve means causing said control valves to momentarily pressurize one of said upper chambers and depressurize the other of said upper chambers during start-up of said intensifier, whereby said piston members initially assume oppositive positions in said cylinder means; common outlet means receiving fluid pressurized in said lower chambers, including means providing communications of said lower chamber with said common outlet means during said pressurization and discontinuing communication during said return movement.

Images