DE2424981A1 - PISTON PRESSURE AMPLIFIER - Google Patents

Description

Patent attorneys

Dipl. Ing. H. Haudc - Dipl. Phys. W. Schmitt

Dipl. Ing. E. Graalfs - Dipl. Ing. W. Wehneri

8 E / iür: cl.G: 3 2, Mo? .3r; LS? Aße 25

Telephone 5330586

The bendix Corporation

Executive offices

Bendix Center May 14, 1974

Southfield, Me. 48o75, U.S. Attorney File M-31o6

Piston pressure booster

i) Cutting of different materials with the help of a high pressure liquid jet has been known for a long time and has been experimentally tested. A practical industrial application of this
However, the process was previously due to various technical
Problems not possible, one of which is the creation of a suitable source of high pressure fluid.

This is a difficult problem as pressures generally exceed

2000 kg / cm and in most applications pressures in the

2
Of the order of 3500 to 5000 kg / cm or more are required, and the liquid under these pressures must be supplied continuously in order to achieve clean cuts.

In addition, in many cases the blasting device must be moved over the workpiece, for example when automatically cutting patterns, and there flexible hydraulic lines and couplings for
such pressures are not available, one in size and

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It is extremely desirable to have sensible fluid tubes.

So far, the continuous generation of a liquid stream with pressures of this magnitude only double-acting stepped piston pressure intensifiers known.

However, such pressure intensifiers do not work very satisfactorily, since the risk of bending at these high pressures makes the device particularly difficult because a Three-point support is used. And the components aar avoidance getting stuck during the stroke movements very large and rigid need to be trained. Furthermore, the pressure booster is due the chambers arranged one behind the other with their ends excessively long and bulky.

These deflections also complicate the piston sealing problems and the heavy construction requires significant seal maintenance and thus excessive dead times.

In another known pressure booster, which has a double floating piston contains, some of the difficulties described above are alleviated in the valve arrangement of this pressure intensifier however, it does not create simultaneous pressurization of each Cylinder that is sufficient to precompress fluid in the cylinder at the beginning of the pressure stroke.

In another known pressure booster with a.'a simple acting twin cylinder is an "overlapping" -zw. same-

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early pressurization of the two cylinders at the end of each Cycle to reduce the pressure fluctuations when changing the load from one cylinder to another. However this is System intended for pressures at which the compression for the liquid is negligible. In particular, the fluid supplied by a constant volume source for actuating the pistons. Line such a source would not work at extremely high pressures that would cause considerable compression of the working medium cause, since the compression of the liquid would cause a considerable pressure drop in the piston chambers, what in turn results in a considerable drop in the outlet pressure and thus nullifies the purpose of the overlap «

It has been found that working fluids that are considered incompressible apply, can be compressed considerably, thereby seriously creating a continuous flow of liquid at these higher pressures with the arrangement previously described would be compromised as the compression of the liquid during a considerable part of the pressure stage or pressure stroke takes place in each cycle and consequently the maximum pressure during this lifting part would not be developed.

In order to avoid this disadvantage, according to the invention, a printing pressure more controlled with two single piston pressure intensifiers so that during part of each compression stroke one each piston is fully pressurized with the other piston to create a significant overlap phase in operation. The J

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The return stroke of each piston is brought about by the working fluid, which is supplied under sufficient pressure to counteract the effects of the air bubbles on the volumetric effectiveness of the amplifier and to minimize the continuity of the current and obviate the need for an arrangement for the return hub by means of the actuating fluid.

The invention will now be based on exemplary embodiments and on the basis of enclosed figures explained in more detail. It shows:

Fig. 1 is a schematic representation of a pressure booster with two Single-piston pressure booster devices including the associated hydraulic control circuits,

Fig. 2 is a schematic representation of the two pistons and their associated ones Control at an intermediate stage of the reinforcement cycle ,

Figure 3 is a schematic representation of the two pistons and their associated controls at a more advanced stage the reinforcement cycle,

Fig. 4 is a schematic representation of the start-up valve and the Control valves at the start of boosting operation,

Fig. 5 is a front view of a particular embodiment of the Two-piston pressure intensifier arrangement,

6 shows a view of the amplifier arrangement in the direction of the arrow 6-6 in Fig. 5,

7 shows the section along line 7-7 in FIG. 5, FIG. 8 shows a view of the amplifier in the direction of arrow 8-8 in FIG

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Fig. 5 and

9 shows a schematic illustration of a second embodiment an amplifier arrangement according to the invention.

According to the figures and in particular according to FIG. 1, the inventive Pressure intensifiers a first and a second single piston pressure intensifier device Io and 12 open, -which are controlled by two control valves 14 and 16 actuated by control pressure.

Each booster device Io and 12 has a piston 18 or which is arranged in a cylinder 22 and 24, respectively. Each piston consists of a head piece 26 or 28 large diameter and a head piece 3o or 32 of smaller diameter, which are connected to one another and which together with the cylinder 22 and 24 a determine upper chamber 34 or 36 and a lower chamber 38 or 4o,

In principle, this arrangement represents the pressure booster, a pressure medium being supplied to the upper chambers 34 and 36, respectively is, acts there on the pistons 18 and 2o and due to the Difference in area of the connected piston head pieces to increase pressure a working liquid introduced into the lower chambers 38 and 4o serves.

In one embodiment, the larger head had a diameter of 63 mm and the smaller head had a diameter of 16 now, resulting in an amplification ratio of 18: 1

was creating. At a pressure of 350 kg / cm in the feed

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to the upper chambers can thus be a Jruckbeaufschlagung the

2
Working fluid of 5000 kg / cm can be achieved.

uie supplying the pressurized fluid to the upper ones Chambers is carried out by conduits 42, 44 which open into these on the top of the cylinders 22 and 24, around the top of each Head piece of large diameter 26 or 2δ located space to apply pressure.

_ 2

Line flowmxttelquelle 46 is e.g. in the form of a 35o kg / cm pump provided, which may have a memory 48, its connection to the lines 42,44 by the control pressure actuated Control valves 14 and 16 is regulated. *

Flussmxttelquelle 46 and the associated storage 48 must be the fluid in the upper chambers 34 and 36 with im can supply substantially constant pressure under all flow conditions that occur during operation. This is especially true for the overlap phase, which will be discussed in detail later will be described, since the pressurization of the upper chamber at the beginning of the pressure stroke in the cylinder with a fairly rapid increase in volume of the upper chamber as a result of the compression of the working fluid. This out of it Large fluid flow currently resulting must be from the Strömmxttelquelle 46 can be coped with without a substantial pressure drop in the chamber of the cylinder at the end of its Pressure stroke occurs so that there is no corresponding drop in the output pressure occurs.

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Each control valve 14, 16 has a valve piston 5o, 52 which is arranged displaceably in a valve bore 54, 56.

Through the positions of the valve pistons 5o, 52 in the bores 54, 56 Connections of openings 58,6o and 62,64 with openings 66,68 are controlled, so that the valves 14 and 16 are threefold Have mode of action.

The openings 58 and 6o are connected to the fluid source via lines 7o, 72 46, while the openings 62, 64 are connected to a sump 74 via lines 76, 78 and 8o. The openings 66 and 68 are connected to the associated lines 42 and 44.

In the position of the valve piston 5o shown in Fig. 1 is thus the upper chamber 34 of the cylinder 2 2 is connected to the sump 74 above the head piece of large diameter, since the opening 58 blocked by the collar 82, while in the position shown of the valve piston 5 2, the upper chamber 36 of the cylinder 2 4 is above of the large diameter header 28 with the fluid source 46 is connected because the collar 8 4 blocks the opening 6 4. In the opposite positions of the valve piston is the opposite of Case in which the collar 86 would block the opening 6 2, whereas the collar 88 blocks the opening 6o.

The position of the valve pistons 5o and 5 2 in their associated bores 54 and 56 is through the at their opposite ends

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3ο, 92 and 94.96 applied control pressures determined by the Movement of the pistons 18 and 2o in the cylinders 22 and 24- caused will. This is done with the help of control lines 9 8, loo and Reaches Io2, lo4, which are connected to chambers Io6, lo8, llo and 112 are, which are each arranged behind a corresponding valve piston end 9o, 92, 9 4 and 3 6.

The control line 9 8 has a control opening 114 in the cylinder 22 connected so that it is in the lowest position of the piston 18

is open and the pressure of fluid source 46 to the chamber Io6 directs. Jie control line loo is with the one in cylinder 2 4 Opening 116 connected so that at an intermediate point in the downward stroke of the piston 2o the opening 116 is opened and the Directs fluid source pressure to chamber to8. The control line Io2 is connected to a control opening 118 located in the cylinder 2 2, so that in a similar manner in the case of an Äischenpurikt in the downward stroke of the piston 18, the opening 118 is opened and the Directs fluid source pressure to chamber 112. The control line Io4 is connected to a control opening 12o in cylinder 2 4, so that it is opened in the lowest position of the piston 2o in a similar manner and the pressure of the fluid source to Chamber Ho directs.

In order to hold the valve pistons So, 52 in the positions reached by the application of the control pressures, mechanical locks 122 and 12 4 can be provided. There can also be a hydraulic locking of the chambers lob ₅ lo8, Ho ^- and 112 or

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magnetic locks are used in the form described later.

To ensure correct synchronization of pistons 18 and 2ο during the start of the stroke, a start-up valve 126 is provided, the lines 128 and 13o briefly pressurized and causes that the valve piston 5o, 52 are positioned in a manner described in more detail below, while these lines normally via the line 132, as shown in Fig. 1, are connected to the sump 74 and the operation of the device is not influence.

Line source 134 for the working fluid supplies the lower Chambers 38 and 4o via lines 136 and 138, check valves 14o and 142 and lines 144 and 146 with working fluid. For In many cutting operations, water is preferably used for cutting and the apparatus is described accordingly. Since oil is the preferred liquid for hydraulic systems such as the pressure booster according to the invention, there is thus one thing two fluid working device. The water is under

relatively high pressure fed, e.g. 200 kg / cm in the device described, while in known pressure intensifiers with different fluids and working media, the working fluid and the fluid are fed in with almost no pressure alone must cause the return stroke.

As a result, the influence of the formation of bubbles in the working fluid-j yrelle 134 on the volumetric efficiency of the system

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kept very small, as their volume is greatly reduced from the start will. In addition, no special return device is required for the fluid, since the high-pressure working fluid is used to return the pistons to their original position after pressurization ensures, because the working fluid pushes each piston upwards as soon as there is no fluid to its associated upper one Chambers 34 and 36 reached.

During the compression stroke of each piston 18, 2o the Working fluid to a common outlet device, depending on Purpose e.g. a liquid jet cutting system 148, via check valves 15o, 152 and lines 154,156 and 15 8 headed. An alternating and overlapping pressurization of the cylinder thus causes the liquid under high pressure is fed to the cutting device. From this description it will be understood that the check valves 15o and 152 one Prevent lower chambers 38 and 4o from communicating with the common outlet device unless the chambers are pressurized applied.

The cutting device may include a pressure vessel 16o and a nozzle 162.

On the basis of FIGS. 2 and 3, the operation of this system after start-up can be easily understood. Assuming that the pressure booster is pressurized in the manner shown in Fig. 1, that is, the upper chamber 30 of the cylinder 24 ₍

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is pressurized and the upper chamber 3M- of cylinder 22 is connected to the sump, then the piston 2o will move down and the liquid in the lower chamber 4o below Put pressure.

When the piston 2o has an intermediate position in the course of its compression stage has reached, as shown in Fig. 2, then the control port 116 is free and by the pressurized fluid applied. This pressure acting via the control line loo in the chamber 9 2 turns the piston valve 5ο to the left in FIG. 2 Press into the position shown there, causing a return pressure the upper chamber 3M and the returned piston 18 over the line 42 is effected.

/ Due to this üruckbeauf impact, the piston Ib will compress the working fluid in the lower chamber 38 while the pressurization at the same time the upper chamber 36 is maintained substantially undiminished.

Therefore, before the return movement of the piston 2o, both pistons 18 and 2o are pressurized and move together afterwards move down (although slower than the piston 2o alone) until the piston 2o reaches the position shown in Fig. 3, in which the Control opening 12o is exposed. The resulting charge back the control line Io4 and the associated chamber Ho then causes the piston valve 52 to be shifted to the right into the position shown in FIG. 3, which in turn results in

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that the chamber 36 is connected to the sump 7Ί and the piston 2o returns.

In the meantime, the piston 18 has reached the position shown in Fig. 3, to a substantially full pressurization and continues to move down, maintaining the outlet pressure.

The size of the overlap is chosen so that the entire compression of the liquid, the lines etc. has taken place at the beginning of each pressure stage and the pressure of the through the amplifier device Io compressed working fluid to the operating pressure of the system has increased before the booster device 12 is depressurized, so that there are no fluctuations in the output current or -pressure occur.

It was found that the pressure for pressures in the specified size

Order, i.e. 5000 kg / cm, the degree of overlap required is considerable is because the main stroke of the piston at the beginning of its pressure stage for "pre-compression" of the working fluid in the lower chamber must be covered before the pressure in the cylinder is reduced at the end of the pressure stage. ;

For example, in the system described and with a stroke of 75 mm, the control openings 116 and 12o of the amplifier device 12 and the control ports 114 and 118 of the amplifier device Io arranged at a mutual distance of 12.5 mm, and '

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the resulting compression path is then of the order of magnitude of 25 mm in order to keep such pressure fluctuations very small.

The piston 18 then moves further downwards (but now faster) until the opening 118 is exposed and thereby the control line Io4 and the chamber 112 are pressurized, whereby the booster 12 is turned on again in a manner similar to the cycle of the piston 2o. When the piston 18 reaches the cylinder base and the control opening 114 is exposed, the control line 9 8 and the chamber Io6 are pressurized, whereby the amplifier device Io is switched off and the Piston 18 moved back.

The cycle repeats itself over and over again as long as there is fluid is fed. The system described was designed for a frequency of 3.65 Hz to generate an output current of 4.8

2
l / min designed at 5000 kg / cm.

The mode of operation of the start-up valve 126 be understood. In the position shown, the valve piston 164 of the start-up valve 12 6 directs the via a line 16 6 and a Port 16 7 from the fluid source 46 and pressurized fluid via an opening 171 and lines 172 and 174 to chambers 168 and 17o of the control valves 14 and 16. As a result, floating pistons 17 6 and 17 8 press the valve pistons 5o and 52 to the position shown in Fig. 4 to properly synchronize their operation. The valve piston 16 4 only remains in front of the j

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transient in this position until there is pressure in a line 18o and a chamber 18 2 builds up the valve piston 16 4 in the figure to the right against the bias of a spring 184 in the position shown in Fig. 1 moves. A collar 186 then blocks the opening 16 7, while a collar 18 8 releases an opening 19o and the lines 172 and 17 4 connects to the sump 7 4 via an overflow line 192. The response of the valve piston 16 4 is controlled by a throttle point 19 4 and a memory Ii) 6, so that its movement is delayed until the valve pistons 5o and 52 have shifted. Optionally, you can also use a electronic actuation and delay or other 'arrangements can be used for this purpose.

This arrangement ensures that the valve pistons are in the correct position at the start of operation in order to

I initiate the process. '

In connection with the start-up, the liquid flow must be in the Feed chambers are throttled sufficiently to speed one up To prevent the pistons' downward stroke, as a relatively low resistance counteracts them until the operating pressure builds up, which in turn could lead to a loss of synchronization if the return stroke of the piston 18 are not completed before the Piston 2o reaches opening 116 and thus initiates a premature working stroke of piston 18.

i For this purpose, throttling points 198 and 2oo can be installed in the

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gen 7ο, 72 could be provided, or the associated openings could can simply be sized appropriately to limit the maximum flow.

In FIGS. 5 to 8 is a particular embodiment of FIG Invention shown.

Two amplifier devices 202,2ο ¹ ! (Cylinders) are arranged side by side and held together with the aid of an upper distributor plate 2o6, a middle distributor plate 2o8 and a lower distributor plate 2Io, which in turn are held together by bolt sets 212 and 214.

Each amplification device 2o2 or 2o4 has a control valve arrangement 216 or 218, with a start-up valve 22o arranged therebetween.

A memory 4 8 corresponding to the one shown schematically in FIG. 1 Memory 222 may be located between amplifier devices 2o2 and 2o4 j

j and provided with a conduit 224 and (not shown) Created [addressed in the upper plate 2O6 be connected.

Fig. 7 shows in section the Verstärkereinri-rect 2O4 and _her trains sound proof control valve 218 and applies in principle to the. Amplifier device 2o2. The booster device 2o4 has a piston 226 with an upper head piece 228 of large diameter, which is arranged displaceably in an upper cylinder 23o and via a self-aligning coupling piece

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231 with a lower head piece 232 running through the middle plate 2o8 and arranged in a lower cylinder 234 smaller diameter is connected.

The upper cylinder 23o has an outer bearing bushing 2 36 and a provided with control openings inner wear sleeve 23 8, of which the lower control shut-off opening 24o is shown and both of them are preferably designed as narrow slots. This shape of the control openings prevents seizure and drive Seal when the piston 226 is moved in the inner wear liner 2 38 reduced.

Each control opening is with openings not shown in the outer sleeve 2 38 in connection, which in turn are connected to control lines 242 and 24 · +. The piston 226 is at the top of the cylinder 2 3o by a fiber disk stop 2 46 and on the underside of the cylinder 2 3o by a spring ring 248.

The lower cylinder 234 has a sleeve 252 drawn over an inner sleeve outer sleeve 25o, with which the inner sleeve 252 is biased against the pressure load. This has proven to be a for cylinder construction has been shown to be suitable for highest pressures.

The dynamic sealing of the head piece 2 32 smaller diameter during the compression stroke is in this embodiment means a leakage control sleeve 254 is reached. This known arrangement creates under high pressure conditions by a pressure difference

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a seal on the sleeve 2S6. Liquid that ai the seal 2b8 seeps past, reaches both the gap 26o and the space between the head piece 2 32 of smaller diameter and the sleeve. Yes, the gap 26o ends in a static stuffing seal 262, the liquid is held there while a leakage flow occurs the head piece of smaller diameter 232 can flow past and through an annular slot 264, a channel 266 and a Line 26 8 can be collected. A pressure difference is thus generated at the sleeve 256 during the compression stroke, as a result of which the sleeve 256 grips the small diameter head piece tightly, however, free movement is allowed during the return stroke.

The control valve 218 has a displaceable in a bore 272 and with the aid of auxiliary pistons 274, 276 and 278 adjustable valve pistons 27o. The valve piston 27o controls the connection of the channel 28o and the opening 281 connected to the return line 282 and the connected channels 284, 286 and 288 and the Feed line 224 and the connected channel 29o, in which dependent from its position in the bore 27 2 either the opening 292 or 2 9 4 is blocked.

The auxiliary piston 27 4 is actuated by the pressure obtained via the control opening 24o and the control line 244, and the auxiliary piston 276 by the pressure obtained via the control line 29 6 'connected to the "on" control opening of the opposite booster device'lo'l is, while the piston 278 is obtained by the via line 293 from the start-up valve 2 2o (Fig. 6)

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, Pressure actuated.

Two permanent magnets 3oo and 3o2 are used for locking, with the valve piston 2 7o in between due to the magnetic attraction one or the other position is held until this is overcome by üie auxiliary piston.

Lin leakage current to the auxiliary pistons 274,276 and 278 is over Recesses 3o4,3o6 at each end of the bore 272, as well as the openings 294 and 3o8 and the channels 31o and 288 are collected and inserted into forwarded the return channels 286,284.

To avoid any leakage on the large diameter head 22 8 past. and to collect from the control openings, as well as a replenishment of the space behind the head piece 22 8 of large diameter during the return stroke with the aid of the return flow is a conduit 312 which is connected to a channel 314 which in turn is provided with an annular channel 316 and an opening 318 in Connection.

Thus, the fluid can be displaced above the head piece 228 during the return nub through the opening 294, the channels 288, 286, 284 into the line 312 and the channels 314, 316 and 318 flow into the area behind the headpiece, which minimizes drag on the return stroke.

The working fluid is via the line 32o and the inlet

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Check valve 32 2 is supplied and enters the lower cylinder 234 via channels 324,326. Takes place during the compression stroke flow into channels 326,328 past outlet check valve 33o into the slot 332., the channel 34o (FIG. 8) to the output channel 342 instead. The nozzle arrangement of the jet cutting device could screwed directly into the channel 34 2 to receive the output current will.

This particular embodiment works as it is based on the Figs. 1 to 5 has been described.

In the case of the FIGS. 1 to 5 shown embodiment Difficulties arise due to unequal pressures in the lower chambers are caused by the same pressures in the upper chambers 3, 4 and 36, if there are considerable manufacturing tolerances with respect to different piston areas, different friction, etc. are present. This pressure difference in the lower chambers could inhibit the movement of the piston at the end of its pressure stroke or its pressure stage, before the last openings 114 or 12o has released.

In contrast, the potential difficulty is avoided with the embodiment in FIG. 9 in that the means for generating the "shutdown" signal are modified there. In this embodiment, the "shutdown" signal from openings 344 and 346 in the amplifier devices Io and 12 or derived in their cylinders, these openings being arranged so high that the KoI- _t

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have already performed their pre-compaction at the point at 18 or under where these openings are exposed. These openings 344 and 346 are connected to the chambers Io6 and 112 of the valves via lines 348 and 35o 14 and 16 connected so that the piston "turned off" at the end of its cycle "will when the other piston is releasing its Control port 344 or 346 has moved sufficiently. As a result, the aforementioned locking or stalling cannot occur because - even if the piston is stopped in its movement with the reaching of the full pressure of the approaching piston the following processes continue, because they do not depend on the further path of the piston at the end of its stroke.

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Claims (1)

Claims j 1. fluid-operated pressure intensifier with a first and a second piston pressure booster, each having a stepped piston arranged in a double cylinder, with im Double cylinder an upper chamber for one head piece of the piston and a lower chamber for the other head piece of the Piston \ provided, and with a facility that has a source constant pressure to supply fluid to the lower chambers without a substantial pressure drop occurring as a result of a flow into the upper chambers by a control device for cyclic pressurization of the upper chambers (3 * 1.36) through a connection with the pressure source (134), whereby the piston (18.2o) to üruckbeaufschlagung of the fluid in the lower chambers (38, 4o) are moved alternately, and the one device (14,16) has, with which each piston is moved into an initial position after the pressure stage, and a device with which both upper chambers can be pressurized at the same time, and a device with which both pistons simultaneously to. Pressurization of the lower chambers before the return movement 409851/0774 one of the pistons by the simultaneous pressurization be moved j with a common outlet 15 8 provided for the fluid pressurized in the lower chambers and means for providing communications between the lower chambers and the common outlet during pressurization and to break the connection during the return movement. 2. Pressure booster according to claim 1, characterized in that the control device (2), with each of the piston pressure booster (Io, 12) has related control valves (14,16) which for the simultaneous pressurization of the piston pressure intensifiers can be actuated independently of one another. 3. Pressure booster according to claim 1 or 2, characterized in that that the control device has a device for pressurizing the upper with a returned piston (18, 2o) Has connected chamber (34,36) to whom the one with the pressurization
ι hit chamber connected piston to an intermediate position the trail reached during its return stroke. : 4. Pressure booster according to claim 3, characterized in that the control valves (14,16) for simultaneous pressurization the piston pressure booster can be actuated depending on the intermediate piston position. 5. Pressure booster according to claim 1, characterized in that! the device for supplying fluid ignite lower 409851/0774 Chambers (38, Ho) and the two pistons to an initial position bringing means means means for supplying fluid under pressure to the lower chambers after interruption the pressurization. 6. Pressure booster according to claim 5, characterized in that the fluid is a liquid and is pressurized above 2
35o kg / cm is applied which causes the pistons (18.2o) to return quickly and minimizes the effect of bubbling on the effectiveness of the pressurization. 7. Pressure booster according to claim 3, characterized in that
the device which brings the pistons (18, 2o) into an initial position has a device (IHo, 112; 15o, 152) for interrupting the i) re-loading in the associated upper chambers, the interruption depending on whether each of the pistons has its position full pressure bevel reached. 8. Pressure booster according to claim 2, characterized by a
driving valve (126), .that causes the control valves (IH, 16)
temporarily pressurize one of the upper chambers (3H, 36)
and during the start-up of the pressure booster, the pressure is released from the other upper chamber, as a result of which the pistons (18, 20) initially assume opposite positions in the cylinders. 409851/0774 Blank page