Compressor arrangement with stacked compressor heads

Abstract

The invention relates to a diaphragm compressor arrangement comprising, at least one first diaphragm compressor including a first diaphragm arranged between a first hydraulic fluid chamber and a first gas chamber, at least one second diaphragm compressor including a second diaphragm arranged between a second hydraulic fluid chamber and a second gas chamber, a stacked head manifold comprising a first hydraulic fluid supply chamber, a second hydraulic fluid supply chamber and a cylinder wherein said first hydraulic fluid supply chamber is in fluid communication with said first hydraulic fluid chamber, wherein said second hydraulic fluid supply chamber is in fluid communication with said second hydraulic fluid chamber, and wherein said first and second hydraulic fluid supply chambers are furthermore in fluid communication with said cylinder, and a piston mechanically connected to a crankshaft, said crankshaft is configured for linear actuation of said piston in said cylinder.

Description

COMPRESSOR ARRANGEMENT WITH STACKED COMPRESSOR HEADS Field of the invention

[0001] The invention relates to a compressor arrangement with at least two stacked compressor heads both having hydraulic fluid supply chambers and a shared cylinder comprised by a stacked head manifold.Background of the invention

[0002] In the art compressor arrangements with more than one head is known e.g. from US12025118. In this document two compressor heads are sharing the same piston. By movement of the piston, volume of a plurality of chambers established between piston, piston bore and oil support plate and between piston, hard stop and drive housing are changing thereby moving hydraulic fluid towards or away from a diaphragm of the two compressor heads. The movement of the piston is facilitated by a hydraulic drive.

[0003] The design of prior art compressor arrangements, such as the one disclosed in US 12025118, is inflexible both in terms of hydraulic control and in terms of changes of compressor head capacity.Summary of the invention

[0004] The inventors have identified the above-mentioned problems and challenges related to pressurizing gas and solved these problems by the present invention as described below.

[0005] In an aspect, the invention relates to a diaphragm compressor arrangement comprising, at least one first diaphragm compressor including a first diaphragm arranged between a first hydraulic fluid chamber and a first gas chamber, wherein said first diaphragm is substantially flat in a first diaphragm plane when said first diaphragm is in neutral position, at least one second diaphragm compressor including a second diaphragm arranged between a second hydraulic fluid chamber and a second gas chamber, wherein said second diaphragm is substantially flat in a second diaphragm plane when said second diaphragm is in neutral position, a stacked head manifold comprising a first hydraulic fluid supply chamber, a second hydraulic fluid supply chamber and a cylinder wherein said first hydraulic fluid supply chamber is in fluid communication with said first hydraulic fluid chamber, wherein said second hydraulic fluid supply chamber is in fluid communication with said second hydraulic fluid chamber, and wherein said first and second hydraulic fluid supply chambers are furthermore in fluid communication with said cylinder, an a piston mechanically connected to a crankshaft, said crankshaft is configured for linear actuation of said piston in said cylinder.

[0006] A stacked compressor head manifold, also referred to as a stacked head manifold or common housing, with hydraulic fluid supply chambers is advantageous in that it has the effect that it allows for a flexible designed. Hence, these volumes can be arranged in the stacked head manifold independent of each other, with different sizes / volumes. This allows for designing a compressor housing in which hydraulic fluid can be recirculated between chambers leading to a more efficient compressor arrangement compared to known compressor arrangements.

[0007] Further, a stacked head manifold with hydraulic fluid supply chambers is advantageous in that such compressor block can be used for a compressor arrangementwith differential head design. Hence, two heads connected to the stacked head manifold may have different gas mass flow output caused by e.g. different size of diaphragm and / or hydraulic fluid chambers.

[0008] Further, a stacked head manifold with hydraulic fluid supply chambers is advantageous in that the piston move in cylinder with fluid communication to these volumes and not in the actual volumes. Accordingly, this design allows the freedom to design the compressor arrangement with different capacity diaphragm compressors, more specific with different diaphragm / fluid chamber sizes on the same drive i.e. on the same set of piston and cylinder.

[0009] Further, this is advantageous in that it has the effect, that asynchronous control between the two diaphragm compressors can be controlled and in that the timing between control of diaphragm displacement in the two diaphragm compressors can be controlled.

[0010] Further, by having the piston and hydraulic fluid supply chambers in the same block lead to a compact design of the stacked head manifold. Such compact design, comprising both piston / cylinder and the supply chambers are advantageous in that length of the oil column is reduced compared to implementations using piping to move the hydraulic fluid and thereby the diaphragm. The oil column in this example exists between the cylinder 14 and the supply chamber 11 or between cylinder 14 and the supply chamber 12.

[0011] A diaphragm is in its neutral position when there are e.g. no or equal forces acting on its sides i.e. from the hydraulic chamber and from the gas chamber respectively. A diaphragm is one or more sheets of metal which is also in its neutral position i.e. flat, when not mounted and laying on a table. When mounted, the diaphragm is parallel, in its neutral position, with the hydraulic and gas plates between which it is mounted

[0012] The piston should be understood as a linear actuation member such as a rod reciprocating in a cylinder. The movement of the piston is provided by its mechanical connection to a crankshaft via piston rod. When the piston is moving in the cylinder,it is moving hydraulic fluid from the cylinder to the fluid supply chamber, from there to the fluid chamber where it deforms the diaphragm towards the gas chamber and thereby pressurizing the gas therein.

[0013] In an exemplary embodiment, said stacked head manifold is a common compressor housing manifold.

[0014] A common compressor housing manifold should be understood as a common compressor housing that comprises at least one cylinder and a plurality of channels for guiding hydraulic fluid from one volume to another volume and a plurality of channels for connecting sensor elements of sensors and / or actuating elements of valves in channels of the stacked head manifold to the relevant location for sensing and / or regulating. The sensor logics / control and valve logics / control may be located either in the stacked head manifold, partly in the stacked head manifold or external to the stacked head manifold.

[0015] In an exemplary embodiment, said cylinder and said first hydraulic fluid chamber is in fluid communication via a first fluid channel, wherein said cylinder and said second hydraulic fluid chamber is in fluid communication via a second fluid channel, and wherein said first fluid channel and said second fluid channel are displaced relative to each other along a longitudinal axis of said cylinder.

[0016] This is advantageous in that it has the effect, that the first and second compressor heads are controlled asynchronously. The displacement allows bidirectional flow of hydraulic fluid between the cylinder and both of the first and second hydraulic fluid supply chambers. This mean that no continued injection of hydraulic fluid is needed. This is because hydraulic fluid travels from one of the hydraulic fluid chambers to the other in dependency of the position of the piston in the cylinder and direction of movement of the piston. Hence, hydraulic fluid may not need to be injected from an external pressure source, hydraulic may only need to be injected from an external source in case of leakage e.g. between the piston and the cylinder wall. Further, if one or more of the compressor heads are replace with compressorheads having larger hydraulic chambers, then injection of hydraulic fluid may also be needed from an external source,

[0017] In an exemplary embodiment, said first fluid channel and said second fluid channel are provided as conduits arranged inside said stacked head manifold and / or in said cylinder housing,

[0018] Having these channels fluidly connecting cylinder and chambers made inside, as part of the monolithic, the stacked head manifold, as part of the monolithic cylinder housing or partly defined by the stacked head manifold and cylinder housing is advantageous in that it has the effect avoiding piping. Piping requires connections which may leak over time.

[0019] In an exemplary embodiment, the length of said first fluid channel is different from the length of said second fluid channel.

[0020] This is advantageous in that it has the effect, that the fluid supply chambers can be physically located the same distance from an end of the cylinder or stacked head manifold and still the piston can allow passage to the cylinder at different times during one stroke of the piston.

[0021] In an exemplary embodiment, said first hydraulic fluid supply chamber is having a fixed volume

[0022] In an exemplary embodiment, said second hydraulic fluid supply chamber is having a fixed volume

[0023] A fixed volume i.e. a volume that do not change in size in dependency of movement of the piston is advantageous in that it has the effect that timing in displacement of the diaphragms in the two diaphragm compressors can be controlled independently.

[0024] In an exemplary' embodiment, the volume of said hydraulic fluid supply chambers is independent of the position of said piston in said cylinder.

[0025] This is advantageous in that it has the effect, that if for some reason the length of a piston stroke is to be increased, this can be done solely by making changes to the piston, piston rod and / or cylinder i.e. no modifications are needed to the supply chambers,

[0026] In an exemplary embodiment, said first hydraulic fluid supply chamber is arranged in said stacked head manifold between said first compressor head and the two distal ends defining said cylinder,

[0027] In an exemplary embodiment, said second hydraulic fluid supply chamber is arranged in said stacked head manifold between said second compressor head and the two distal ends said cylinder.

[0028] The l ocation of the supply chambers along the side of the cylinder and thus of the piston is advantageous in that it has the effect, that it allows the piston and its mechanical connection with the crankshaft to extend through the end of the cylinder.

[0029] Further, this location is advantageous in that it has the effect that the stacked head manifold including cylinder can be extended thereby allowing additional heads to be mounted to the stacked head manifold.

[0030] Further, this location is advantageous in that it has the effect that three or more such as four compressor heads can be arranged around stacked head manifold.

[0031] In an exemplary embodiment, said stacked head manifold comprises integrated temperature regulating channels.

[0032] A heat sink may be integrated by providing material in addition to what is needed for structural support of the cylinder and compressor heads. Such additional material may be spaced to form ribs between which air can pass through and thereby cool the stacked head manifold. It should be mentioned that material may also be moved in the stacked head manifold thereby establishing temperature regulating channels in the stacked head manifold. Integrated temperature regulating channels are advantageous in that it has the effect, that a more efficient temperature regulation such as cooling of the compressor arrangement can be established. By cooling the hydraulicfluid, the temperature can be controlled and thereby a beter thermic management is obtained.

[0033] In an exemplary embodiment, said stacked head manifold comprises control valves configured for controlling flow of hydraulic fluid in said first and second hydraulic fluid channels.

[0034] Such control valves are advantageous in that it has the effect that the two compressor heads can be controlled asynchronously.In an exemplary embodiment, said first hydraulic chamber is provided in a first hydraulic fluid plate and wherein said second hydraulic chamber is provided in a second hydraulic fluid plate.In an exemplary’ embodiment, said first gas chamber is provided in a first gas plate and wherein said second gas chamber is provided in a second gas plate.

[0035] Providing the chambers in plates instead of in the converter block is advantageous in that it has the effect, that if one chamber is defect, the plate can be replaced and not the block.

[0036] In an exemplary’ embodiment, said first diaphragm compressor and said second diaphragm compressor are arranged opposite each other on opposite sides of said cylinder.

[0037] + wherein said cylinder is arranged substantially in the middle between said first diaphragm and said second diaphragm.

[0038] + wherein said first diaphragm compressor is pressed against said stacked head manifold and wherein said second diaphragm compressor is pressed against said stacked head manifold by means of through going bolts extending between said first diaphragm compressor and said second diaphragm compressor.

[0039] + wherein said cylinder is arranged in a monolithic cylinder housing and wherein said cylinder housing is arranged in a slot in said stacked head manifold between said first diaphragm compressor and said second diaphragm compressor.

[0040] Providing a cylinder housing for inserting in slot in the stacked head manifold is advantageous in that it is possible to replace the cylinder housing in case of defects in the cylinder instead of the whole stacked head manifold. Hence, the cylinder housing may be established as an insert that fit into a bore in the stacked head manifold. It should be noted that static sealings are provided between the stacked head manifold and the cylinder housing. Static, as there are no movement between the stacked head manifold and cylinder housing.

[0041] In an exemplary embodiment, a first gas intake valve, arranged at the bottom of a first intake bore, is connected to said first gas chamber, wherein a first outlet valve, arranged at the bottom of a first outlet bore, is connected to said first gas chamber, wherein said first intake bore and said first outlet bore are substantially perpendicular to said first diaphragm plane, and wherein a second gas intake valve, arranged at the bottom of a second intake bore, is connected to said second gas chamber, wherein a second outlet valve, arranged at the bottom of a second outlet bore, is connected to said second gas chamber, wherein said second intake bore and said second outlet bore are substantially perpendicular to said second diaphragm plane.

[0042] In an exemplary embodiment, said piston comprise a first piston protrusion and a second piston protrusion extending from the circumference of said piston.

[0043] Piston protrusions are advantageous in that they can be positioned on the circumference of the piston, so that they are closing the fluid passage between the cylinder and the supply chamber. In this way, when on the piston stroke the fluid passage should be closed may thus be determined by the location of the piston protrusion on the piston. The piston protrusion may be monolithic with piston and may be moving in an associated slot in the cylinder housing.

[0044] In an exemplary embodiment, said first piston protrusion is located a third distance from an end of said cylinder housing and wherein said second pistonprotrusion is located a fourth distance from said end of said cylinder housing, wherein said third distance and said fourth distance are different.

[0045] By displacing the first and second piston protrusions it is possible to, by design of the piston, control the timing of closing and opening of the fluid passages between the cylinder and the first and second supply chambers.

[0046] In an exemplary embodiment, said first and second piston protrusions are moving with said piston in first and second slots provided in said cylinder housing.

[0047] This is advantageous in that the flow of hydraulic to the supply chambers and thus to the fluid chambers are controlled without changing the volume size of the supply chambers. Hence, variable hydraulic fluid supply such as injection into the hydraulic system in or between the compressor head and cylinder allows use of variable diaphragm sizes or variable gas pressures, without changing the hydraulic fluid supply chamber volume which thus can remain constant.

[0048] In an exemplary’ embodiment, said linear actuation of said piston allow movement of said piston in a direction substantially parallel with said first diaphragm plane and with said second diaphragm plane.

[0049] In an exemplary embodiment, said first diaphragm plane and said second diaphragm plane are parallel.

[0050] In an exemplary embodiment, said crankshaft is arranged to facilitate reciprocating movement of said piston in said cylinder at least 300 times per minute.

[0051] In an exemplary’ embodiment, said diaphragm compressor arrangement is a high-pressure diaphragm compressor arrangement arranged for pressurising a gas in said first gas chamber of said first diaphragm compressor and pressurising a gas in said second gas chamber of said second diaphragm compressor to a pressure between 10 and 300 MPa, preferably between 20 and 200 MPa, and most preferred between 30 and 130 MPa.

[0052] In an exemplary embodiment, the first compressor head and the second compressor head are identical and wherein the first compressor head is mounted to the stacked head manifold with gas intake valve towards the crankcase and wherein the second compressor head is mounted to the stacked head manifold with gas outlet valve towards the crankcase.

[0053] In an exemplary embodiment, the volume of hydraulic fluid in said first and second fluid chambers are controlled independently from the location of said piston in said cylinder by first and second supply chamber valves

[0054] This is advantageous in that a flexible control regime is provided where the two diaphragm compressors can be controlled independently from each other and independently from the reciprocating movement of the piston.

[0055] Beside such duplex compressor control of compressors with different compression ratios, it is also possible to connect the gas chambers in series and thereby let the first diaphragm compressor be a first step suppling a second compression step i.e. the second diaphragm compressor.

[0056] Further, it should be noted that some diaphragm compressors of the same compressor arrangement may be operated as duplex and some may be operated in series having two or more compression steps.

[0057] In an exemplary embodiment, said first hydraulic fluid chamber, said first fluid channel, said first hydraulic fluid supply chamber, said second hydraulic fluid chamber, said second fluid channel, said second hydraulic fluid supply chamber and said cylinder constitute a main closed hydraulic fluid system.

[0058] A closed hydraulic fluid system is advantageous in that it has the effect, that efficiency of the compressor arrangement is increased in that not force has to be used to push excess of injected hydraulic fluid out of e.g. a hydraulic fluid chamber. Hence, no hydraulic fluid is intentionally leaving the closed hydraulic fluid system during operation. With this said, one way hydraulic fluid may leave the closed hydraulic fluid system is via leakage between cylinder and piston.

[0059] Further, the design of the compressor arrangement can be simplified in that no conduits for guiding excess of hydraulic fluid from the closed hydraulic fluid system and to a reservoir such as the crankcase is necessary'.

[0060] In an exemplary' embodiment, at least a quantity of hydraulic fluid comprised by said first hydraulic fluid supply chamber travels through said first fluid channel, said cylinder and said second fluid channel to said second hydraulic fluid chamber during each stroke of said piston.

[0061] In an exemplary embodiment, an end of said first fluid channel allowing flow of hydraulic fluid between said cylinder and said first fluid channel is positioned a first distance from an end of said cylinder, wherein an end of said second fluid channel allowing flow' of hydraulic fluid between said cylinder and said second fluid channel is positioned a second distance from said end of said cylinder, and wherein said first distance and said second distance are different.

[0062] This bidirectional flow of hydraulic fluid between the two hydraulic fluid supply chambers is advantageous in that it has the effect, that no hydraulic fluid from outside the closed hydraulic system is needed to change pressure in the first and second hydraulic fluid supply chambers during a stroke of the piston. This is true at least when the fluid supply chambers are having identical volumes size.

[0063] In an exemplary embodiment, an oil injection system comprising an injection valve discontinuously supplying oil from a reservoir to said main closed hydraulic fluid system.

[0064] Discontinuously should be understood as not for every piston stroke i.e. oil is only introduced into the main closed hydraulic fluid system when necessary. Hence, depending on e.g. a measured volume or pressure of hydraulic fluid measured e.g. in the first and / or second hydraulic fluid chambers, a controller may open the injection valve and allow a controlled amount of hydraulic fluid to enter the closed compressor control system. This is advantageous in that only the amount of hydraulic fluid needed is introduced leading to a better efficiency of the operation of the compressor.

[0065] The reservoir may be the crankcase or it may be a vessel different from the crankcase such as a hydraulic fluid injection system.

[0066] In an exemplary embodiment, said main closed hydraulic fluid system comprise a relief valve

[0067] A relief valve is advantageous in that it has the effect, that if more hydraulic fluid than required is for some reason in the main hydraulic fluid system, the relief valve may be used to reduce this volume to a required volume and thereby prevent damaging parts of the compressor such the diaphragm. The hydraulic fluid escaping via the relief valve may end in the crankcase.

[0068] In an exemplary embodiment, said diaphragm compressor arrangement further comprises, at least one third diaphragm compressor including a third diaphragm arranged between a third hydraulic fluid chamber and a third gas chamber, wherein said third diaphragm is substantially flat in a third diaphragm plane when said third diaphragm is in a neutral position, at least one fourth diaphragm compressor including a fourth diaphragm arranged between a fourth hydraulic fluid chamber and a fourth gas chamber, wherein said fourth diaphragm is substantially flat in a fourth diaphragm plane when said fourth diaphragm is in a neutral position, an additional stacked head manifold comprising a third hydraulic fluid supply chamber, a fourth hydraulic fluid supply chamber and an additional cylinder, wherein said third hydraulic fluid supply chamber is in fluid communication with said third hydraulic fluid chamber, wherein said fourth hydraulic fluid supply chamber is in fluid communication with said fourth hydraulic fluid chamber, and wherein said third and fourth hydraulic fluid supply chambers are furthermore in fluid communication with said additional cylinder, and an additional piston also mechanically connected to said crankshaft, wherein said crankshaft is furthermore configured for linear actuation of said additional piston in said additional cylinder.

[0069] In an exemplary embodiment, the direction of said linear actuation of said piston and the direction of said linear actuation of said additional piston is substantially parallel.

[0070] The direction of movement of the piston and of the additional piston may be a direction that is substantially parallel with the third and fourth diaphragm planes and thus also with the first and second diaphragm planes.

[0071] In an exemplary embodiment, said first diaphragm compressor, said second diaphragm compressor, and said cylinder are arranged on a first side of said crankshaft, wherein said third diaphragm compressor, said fourth diaphragm compressor, and said additional cylinder are arranged on a second side of said crankshaft and wherein said first side is opposite said second side.

[0072] If the stacked head manifold is a square, four diaphragm compressors may be mounted to the stacked head manifold and share the same cylinder / piston arrangement. Similarly, if the stacked head manifold is a pentagon, hexagon, etc. 5, 6, etc. diaphragm compressors may be mounted to the stacked head manifold and shared the same cylinder / piston arrangement.

[0073] In an exemplary embodiment, said first diaphragm compressor is substantially identical to said third diaphragm compressor, wherein said second diaphragm compressor is substantially identical to said fourth diaphragm compressor, and wherein said cylinder is substantially identical to said additional cylinder.

[0074] In an embodiment, the invention relates to a diaphragm compressor arrangement according to any of the preceding claims for pressurising hydrogen in a hydrogen fuelling station.The drawings

[0075] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent likeparts. The drawings illustrate embodiment of the invention and elements of different drawings can be combined within the scope of the invention:Fig. 1 illustrates a stacked head manifold to which two compressor heads are connected,Fig. 2 illustrates a cut through at line A of fig. 1,Fig. 3a illustrates the stacked head manifold and part of the two compressor heads in a detailed view,Fig. 3b illustrates an alternative embodiment of the stacked head manifold and part of the two compressor heads in a detailed view, andFig. 4 illustrates a stacked head manifold with four compressor heads.Detailed description

[0076] The present invention is described in view of exemplary embodiments only intended to illustrate the principles and implementation of the present invention. The skilled person will be able to provide several embodiments within the scope of the claims which may not be directly illustrated in the figures or directly described below.

[0077] Fig. 1 illustrates a compressor arrangement 1 according to an embodiment of the invention. The illustrated compressor arrangement 1 comprise a first diaphragm compressor 2 and a second diaphragm compressor 3 mounted on opposite sides of a stacked head manifold 10 by through going bolts. The bolts may secure the compressor heads to the stacked head manifold 10 via threaded parts in the stacked head manifold. The compressor arrangement 1 is particularly advantageous for use in pressurizing gas such as hydrogen but are suitable for pressurizing other types of gases.

[0078] The diaphragm compressors 2, 3 both comprise gas plates 20, 21 and hydraulic fluid plates 18, 19 between which diaphragms (not illustrated in fig. 1) are provided. The stacked head manifold 10 is mechanically connected to a powerframe also referred to as a crankcase 46. The crankcase 46 comprise one part 46b enclosing the actual crankshaft and one part 46a enclosing the piston rod and piston 13. The crankshaft is driven by a rotational drive such as an electrical motor and in this way, a piston rod, mechanically connected to a crankshaft, is facilitating a reciprocating movement of the piston 13, in the cylinder 14 comprised by the stacked head manifold 10. The drive for the crankshaft may alternatively be hydraulic, a rotational drive is preferred where a motor drives the crankshaft e.g. via a direct drive, belt, chain or the like.

[0079] Sensors 50 are illustrated as going into the hydraulic fluid plates 18, 19. These are for measuring e.g. temperature and / or pressure in the hydraulic fluid supply chambers 11, 12. Also, a regulation valve 51 is illustrated which are used to control the flow of hydraulic fluid between the hydraulic fluid supply chambers 11, 12 and the hydraulic fluid chambers 4, 8. A controller 49 is controlling the these valves 51 at least partly based on input from these sensors 50. The controller 49 may also control gasvalves (not illustrated) based on input from temperature and pressure sensors (not illustrated) measuring the temperature and pressure in the gas chambers 5, 9, Thus the controller 49 may be a compressor arrangement controller controlling the diaphragm

[0080] Fig. 2 illustrates a cross-sectional view of the compressor arrangement illustrated in fig. 1. Specifically, a cross-sectional view of the two diaphragm compressors 2 are illustrated at line AA. The cross-sectional view illustrates that the piston 13 is reciprocating in a cylinder 14 which is comprised by a cylinder housing 22. The cylinder housing 22 is comprised by the stacked head manifold 10.

[0081] From the cylinder 14 first and second fluid channels 16, 17 are fluidly connecting the cylinder 14 and the first and second hydraulic fluid supply chambers 11, 12. These chambers 11, 12 are having a fixed volume and are provided in the stacked head manifold 10 with fluid communication through the hydraulic fluid plates 18, 19 to the hydraulic fluid chambers 4, 8. Hence, a hydraulic fluid system (can be referred to as a closed hydraulic fluid system) is provided having compressor zones, intermediate zones and a cylinder zone. The closed hydraulic fluid system is provided between the first hydraulic fluid chamber 4 through channels in the first hydraulic fluid plate 18, the first hydraulic fluid supply chamber 11, the first fluid channel 16, the cylinder 14, the second fluid channel 17, the second hydraulic fluid supply chamber 12, channels in the second hydraulic fluid plate 19 and the second hydraulic fluid chamber 8. Hence, the compressor zones include the fluid chambers 4, 8, the intermediate zones include the fluid supply chambers 11, 12 and the cylinder zone include the cylinder 14. These zones are fluidly connected by channels 16, 17, 48.

[0082] In an ideal scenario where there is no leaking of hydraulic fluid, in this closed hydraulic fluid system. No matter the extend of leakage, the hydraulic fluid is allowed to travel between the fluid chambers 4, 8 as consequence of the movement of the piston 13, Injection of hydraulic fluid may be controlled by a hydraulic control system as described in US11815081 and WO2024217650 which are hereby both incorporated by reference

[0083] Leakage may occur between the piston 13 and cylinder 14 and in case of leakage, a determined amount of hydraulic fluid may be injected into the cylinder 14 from a hydraulic fluid control system. Further, for safety reasons, a relief valve may allow venting the closed hydraulic fluid system for hydraulic fluid e.g. in the case pressure hereof increases above a predetermined pressure.

[0084] The compressor arrangement 1 may be referred to as a modular compressor arrangement. This is because the stacked head manifold 10 is a modular component in which a cylinder housing 22 can be inserted and to which compressor heads 1, 2 can be mounted via hydraulic fluid plates 18, 19. The outer diameter of the cylinder housing 22 fit the bore in the stacked head manifold 10. The cylinder diameter inside the cylinder housing may have a certain diameter. Hence, a cylinder diameter may be changed by changing the cylinder housing 22. Thus, the cylinder housing 22 could be said to have a standard size in that its outer dimensions correspond to a bore, having matching / corresponding dimensions, inside the stacked head manifold 10. The fluid plates 18, 19 may be sized so that their outer dimensions match the / correspond to sides of the stacked head manifold to which they are mounted. Thus, the cylinder housing 22 and the fluid plates 18, 19 may be referred to as modular compressor elements i.e. elements for a modular compressor arrangement. Non-limiting examples of outer diameter of cylinder housing 22 are between 60mm and 100mm, such as between 70mm and 90mm such as 80mm. Non-limiting examples of cylinder 14 diameter are between 15mm and 45mm, such as between 25mm to 35mm such as 30mm.

[0085] The stacked head manifold comprises hydraulic fluid supply chambers 11, 12 which are volumes that are at least partly established in the stacked head manifold 10. These chambers 11, 12 may at least partly be defined by one or more of the cylinder housing 22, hydraulic fluid plates 18, 19 and the stacked head manifold 10. The volume of these chambers 11, 12 may be identical or at least substantially the same, also if the compressor heads 1, 2 are not identical e.g. measured in capacity / volume of e.g. hydraulic fluid chamber or gas chamber. The reason why it is possible to have supply chambers 11, 12 with substantially the same volume is because the flow ofhydraulic fluid between these chambers 11, 12 and the respective hydraulic fluid chambers 4, 8 are controlled independently as will be described below. It should be mentioned, that due to the individual control, the volumes may not need to have substantially the same volume.

[0086] Passages 48 are illustrated in the stacked head manifold 10 from the cylinder 14 and out to an outer edge of the stacked head manifold 10. This is just to indicate that a channel for injection and / or another channel for relief of hydraulic fluid from the cylinder is provided. It should be noted that at least the channel for injection of hydraulic fluid may also or alternatively, end in one or both of the supply chambers 11, 12.

[0087] The stacked head manifold 10 and also the cylinder housing 22 may be made of metal such as a variant of steel i.e. Iron with various alloys. One or more valves 50 may be implemented as so-called manifold valves i.e. a valve block 44 with specifically designed cavities, channels and integrated valve. Alternatively, one or more valve 50 may be integrated into the stacked head manifold 10. No matter which of the implementations, the valves may have mechanic actuators through valve channels 43 at the relevant location such as in or at the end of a fluid path 48 between the supply chamber 11 and hydraulic fluid chamber 4. Valves may also be implemented as line valve that are individually positioned and connected with piping in which they can control / regulate flow of hydraulic fluid. Only valve and sensors are illustrated in relation to one of the compressor heads.

[0088] The outer dimensions of the cylinder housing 22 is preferably the same no matter the diameter and length of the cylinder 14 comprised by the cylinder housing 22 and no matter the diameter and length of cavities forming or at least partly forming the fluid channels 16, 17. Therefore, the cylinder housing 22 of the present invention may be referred to as a modular component due to its outer dimensions.

[0089] Its inner dimensions however may be different from one cylinder housing to another and still have the standard outer dimensions. An example could be cylinder housings 22 having different size of the cylinder 14 such as different diameter and / ordifferent lengths. Another example may be the hydraulic fluid channels 11, 12 which may have different length, diameter and path layout from cylinder opening to hydraulic fluid supply chamber opening.

[0090] Another example may be the number of hydraulic fluid channels 11, 12 that are established in the cylinder housing 22. As mentioned there may be more than two compressor heads connected to the same stacked head manifold 10 which will require more than two fluid channels as illustrated in fig. 2 and sometimes also a longer cylinder 14.

[0091] Hence, as the diameter and length of the bore in the stacked head manifold 10 and the outer diameter of the cylinder housing 22 are matching, then a cylinder housing 22 with an internal design (e.g. cylinder and fluid channel dimensions) complying with requirements to the diaphragm compressors 1, 2, that are needed to fulfil the requirements to the compressor arrangement, can be selected.

[0092] The implementation of the cylinder housing 22 having a cylinder 14 independent of the physical volume / size of the supply chambers 11, 12 is advantageous in that the length of the piston stroke can be changed such as extended without any changes to the stacked head manifold 10 or diaphragm compressors 1, 2.

[0093] Alternatively, if there is not sufficient space in the cylinder 14 for making the piston stroke longer then, by this modular approach a cylinder housing 22 of the compressor arrangement may be changed or replaced by a cylinder housing having a longer cylinder without changing any other hardware.

[0094] In an embodiment, the cylinder 14 is established as a bore in the stacked head manifold 10. Alternatively, as illustrated in fig. 2, the piston bore 14 is provided in a cylinder housing 22. As mentioned, the cylinder housing 22 may be established as an insert that fit into a bore in the stacked head manifold 10. Such cylinder insert is advantageous with respect to manufacturing and service of the compressor arrangement. Specifically, it is possible to establish channels and cavities in the cylinder housing 22 with smaller tolerance than what is possible to do in a one-piece stacked head manifold 10.

[0095] Should the cylinder be damaged, or the compressor arrangement retrofitted, only the cylinder housing 22 may be replaced and not the entire stacked head manifold 10. Further, the damaged cylinder housing may be replaced with a new one and the old and damaged cylinder housing 22 may be brought home to the garage to be refurbished or recycled. In this way the downtime of the compressor arrangements is reduced.

[0096] The cylinder housing 22 also comprise the first and second fluid channels 16, 17. Again, these are much easier to establish at high precision in the cylinder housing 22 than in the stacked head manifold 10.

[0097] The hydraulic fluid supply chambers 11, 12 (also sometimes referred to simply as supply chambers) are as mentioned fixed volume chambers one for each of the diaphragm compressors 1, 2. These may in principle be located anywhere in the stacked head manifold 10 between the cylinder housing 22 and the hydraulic fluid plate of the respective diaphragm compressors 1, 2. Hence, they are located in the flow path between the cylinder and a hydraulic chamber. It is preferred that they are at least partly defined by the cylinder housing 22 in that the fluid connections from the cylinder 14 is easier to make with high precision in the cylinder housing 22 than in the stacked head manifold 10.

[0098] The supply chambers 11, 12 may in principle have any volume size. The volume of a fluid supply chambers 11, 12 determined by designed of one or more of the gas volume, compressor head design, hydraulic fluid control system, etc. in any combination. As a rule of thumb, if the hydraulic fluid control system injects hydraulic fluid directly into a supply chamber 11, 12 it may be smaller in volume than the associated fluid chamber 4, 8. Further, if the injection of hydraulic fluid is provided into the cylinder, the volume of the supply chamber 11, 12 may be larger than the associated fluid chamber 4, 8.

[0099] The supply chambers 11, 12 are fluidly connected to their respective / associated fluid chamber 4, 8 via fluid paths 48. The flow from the first supply chamber 11 to the first chamber 4 is controlled by regulation valves (not illustrated). In the sameway, the flow from the second supply chamber 12 to the second chamber 8 is controlled by another regulation valve (not illustrated). In this way it is possible for the controller 49 to control the flow to the two fluid chambers 4, 8 individually. This is advantageous in that it is possible to control the two diaphragm compressors 1, 2 individually including an asynchronous control, it is possible to control two diaphragm compressors having different capacity such as different mass flow (of gas) capacity. Such asynchronous control may result in a pressurized first diaphragm compressor when the second diaphragm compressor is non-pressurized and vice versa.

[0100] It should be noted that the valve 50 may be integrated in one or more valve blocks 44 and thereby be manifold mounted or integrated in the compressor housing 10. From such manifold mounted valve, a valve passage 43 is provided to the channel or location where the valve needs to control flow of hydraulic fluid. The valves may be electrically, hydraulic or pneumatically controlled.

[0101] The shape or geometry of the supply chambers 11, 12 do not need to have any particular geometry, hence, the geometry that is easiest to machine in the stacked head manifold 22 may be chosen. With this said, the geometry of the supply chambers may not be identical e.g. as illustrated in fig. 2. The geometry may be specific to the geometry and / or volume of the cylinder 14 and / or of the hydraulic chambers 4, 8 of the heads 2, 6 they supply. Such specific geometry may be determined as a ratio of size between hydraulic fluid chamber and supply chamber. On fig. 2 the ration is misleading even though the size / volume of the supply chamber is large than the size / volume of the hydraulic chambers. As an example, the supply chamber volume may be between 10% and 50% larger than the hydraulic fluid chamber such as between 20 % and 40% such as 30% larger.

[0102] The volume of these supply chambers may be in the range of 40cm3 to 100cm3. A geometric characteristic of a supply chamber may be that it is wider than the fluid paths 48 and fluid channels 16, 17. Further, it should be noted that the supply chambers 11, 12 may be longer than wide because the area in the stacked head manifold between the cylinder and the fluid plates 18, 19 may be limited. Thus, the supply chambers may extend parallel to the cylinder to be able to have a sufficientvolume. Hence its center axis parallel to the cylinder may extend parallel to the cylinder for a length that is half the length of the cylinder. Such as between 5cm and up to 60cm e.g. with 2 cm intervals such as 5cm, 7cm, 9cm, etc. In an embodiment, if the stacked head manifold e.g. is 70cm in total length parallel to the cylinder which may be 60cm, and the length of the supply chamber may be 30cm.

[0103] The fluid supply channels 16, 17 (sometimes referred to simply as channels) are having a cylinder end forming a passage from the cylinder 14 to the channels 16, 17 and a supply chamber end forming a passage from the supply chambers 11, 12 to the channels 16, 17. As illustrated in fig. 2, the cylinder ends of the two supply channels 16, 17 are connecting the cylinder 14 and the supply channels 16, 17 at different locations relative to the longitudinal axis of the cylinder 14.

[0104] More specifically in the embodiment illustrated in fig. 2, a fluid connection is established between the supply channel denoted 16 and the cylinder 14, when the piston 13 is moving towards its bottom dead center from a position somewhat close to the center of the supply chamber 11. The fluid connection is established when the piston hard is a distance DI from end 14a of the cylinder 14.

[0105] Similarly, a fluid connection is established between the supply channel denoted 17 and the cylinder 14, when the piston 13 is moving towards its top dead center from a position somewhat close to the center of the supply chamber 12. In the illustration of fig. 2, the center of the supply chambers 11, 13 may be the same position of the piston. The fluid connection is established when the piston hard is a distance D2 from end 14b of the cylinder 14.

[0106] This way of connecting the cylinder 14 and supply chambers 11, 12 is advantageous in that asynchronous movement of the diaphragms of the two diaphragm compressors are facilitated.

[0107] As illustrated in fig. 2, the channels 16, 17 are of different lengths. The length of these channels 16, 17 depend on where the supply chambers 11, 12 are located in the stacked head manifold 10. In fig. 2 these are located symmetrically around the cylinder 14 which is the reason for the different lengths of the channels 16, 17. If thesupply chambers 11, 12 were located with different distances e.g. to the cylinder end 14a the channels 16, 17 may have had the same length.

[0108] As illustrated, the channel denoted 17 is established as a groove in the cylinder housing 22 i.e. not as a complete pipe-like channel. The pip-like channel is first established when the cylinder housing 22 is inserted into the stacked head manifold 10 i.e. the side of the bore in the cylinder housing 22 is partly establishing the channel 17. The channel denoted 16 is established as a simple pipe-like bore in the cylinder housing 22 substantially perpendicular to the longitudinal axis of the cylinder 14.

[0109] Fig. 3a illustrates an embodiment of a stacked head manifold 10 which could be used in the compressor arrangement 1 of fig. 1 and 2. In the stacked head manifold 10 of the compressor arrangement 1 illustrated in fig. 3a, additional details are illustrated compared to the stacked head manifold 10 illustrated in fig. 2. It should be noted that some or all of these additional details may be implemented in the compressor arrangement 1 of fig. 2. Hence, the illustrated features of fig. 3a is only one way of implementing the invention and parts may be located in various different positions relative to each other and thus, not only as illustrated. Hence, the compressor system illustrated in fig. 3b is one such alternative implementation of the invention. It should be noted that aspects are disclosed only with reference to one of the two diaphragm compressors 2, 6 knowing that both may comprise such features.

[0110] As in fig. 2, the diaphragms 3, 7 are illustrated in neural position which in this case is parallel to the piston 13.

[0111] An injection valve 50A is illustrated as connected to the supply chamber 11. Accordingly, if hydraulic fluid is needed it may be injected directly into the supply chambers 11, 12 or into the cylinder 14. The injection valve 50a is implemented as a valve block 44, 50a outside the stacked head manifold 10 with a mechanical valve component also denoted 50a just outside the supply chamber 11.

[0112] A relief valve 50B is illustrated as connected to the cylinder 14. Accordingly, if pressure inside the cylinder exceed a threshold level of the relief valve SOB,hydraulic fluid leaves the cylinder 14. It should be noted that the supply chambers 11 12 may also be connected to a relief valve.

[0113] These valves 50a, 50b are part of a hydraulic fluid control system such as the one disclosed in the above-mentioned applications which are incorporated by reference. As one will know from these documents, hydraulic fluid is only injected into the closed hydraulic system such as into the cylinder 14 or supply chambers 11, 12 when needed. When needed is determined based displacement losses of changes of the diaphragms 3, 7. Diaphragm displacement relative to a target displacement is measured by the hydraulic control system and based hereon, the hydraulic control system is injecting hydraulic fluid if necessary. A target position of the diaphragm is typically just before contact is established between the diaphragm and the wall of the gas chamber.

[0114] Hence, as consequence of piston movement, volume of cylinder changes, leading to change of volume (amount) of hydraulic fluid in the supply chambers 11, 12 which volumes are fixed (in this context the hydraulic fluid is considered incompressible). With reference to only the first supply chamber 11, control of the regulation valve 50C and control of the gas intake and gas outlet valves, the hydraulic fluid in the supply chamber 11 is leading to movement of diaphragm 3 and thus pressurizing the gas in the gas chambers 5.

[0115] Regarding the relief valve 50B, this is not an essential part of the present invention, it is merely a safety arrangement as the skilled person will know and will therefore not be disclosed further. The same is true for the control of the gas intake and outlet from the gas chambers 5, 9. This is also not an essential part of the present invention and will therefore not be disclosed further.

[0116] The control of the regulation valve 50c of the first diaphragm compressor 2 is similar to a partly illustrated regulation valve 50d of the second diaphragm compressor 6. As the control and implementation principles are the same, the control of valve 50C in the channel 48 between the first hydraulic fluid chamber 4 and the first hydraulic fluid supply chamber 11 is illustrated with more details.

[0117] A temperature / pressure sensor 51 is illustrated as one and the same sensor. In practise, this would often be two individual sensors, however for simplicity of the figure, they are here illustrated as one and the same sensor. The purpose of the temperature sensor is to measure temperature of the hydraulic fluid in or close to the supply chamber 11. The purpose of the pressure sensor is to measure pressure inside the supply chamber 11. The end of these sensors is illustrated at the end of a valve / sensor passage 43 extending through the stacked head manifold 10.

[0118] The sensor 51 and the regulation valves 50d, 50c, 50a are all communicating with the controller 49 via communication lines. The relief valve 50b may also communicate with the controller 49 even though not illustrated. Sensors such as those denoted 50 and valves such as those denoted 51 are preferably of the manifold type. This means that they are located external to the stacked head manifold 10 in a manifold / valve block 44 which comprise machined cavities for sensor / valve equipment and channels via which sensor / valve elements have access to the relevant areas in the compressor arrangement 1. Part, of such cavities and channels may be machined into the compressor housing 22. Hence, when one or more manifold blocks 44 comprising one or more sensors and / or one or more valves are attached to the stacked head manifold 10 (e.g. by bolts), the stacked head manifold 10 may be referred to as a central hydraulic manifold or a stacked compressor head manifold. Manifold block(s) may be mounted at the end or at a side of the stacked head manifold 10, where there is no diaphragm compressor mounted.

[0119] Relevant areas may in this context be channels through which flow of hydraulic fluid need to be regulated or volumes in which properties of hydraulic fluid need to be measured. It should be noted that other valve and sensor types may be used to obtain required measurements and flow control.

[0120] It should be noted that parts of the compressor arrangement 1 may comprise alignment pins 45. Alignment pins are used to ensure correct location of, in this case the stacked head manifold 10 and the oil plate 10 so that all channels, seals, etc. are located exactly where needed.

[0121] In an embodiment, the stacked head manifold 10 comprise temperature regulating channels 53 around the supply chambers 11, 12, In this way it is possible to reduce the temperature of the hydraulic fluid, a temperature which is increase in the cylinder 14 due to piston stroke and in the fluid chambers 4, 8 due to the pressurized gas. The temperature is regulated up or preferably down by connecting the temperature regulating channels 53 to a temperature regulation system and thereby allow a flow of temperature regulating fluid pass through the temperature regulating channels 53.

[0122] Accordingly, a desired start temperature of the stacked head manifold 10 may be ensured by circulating a temperature regulating fluid having a temperature higher than the temperature of the stacked head manifold 10. Alternative, the start temperature may be reduced by circulating temperature regulating fluid having a lower temperature than the stacked head manifold 10.

[0123] The temperature regulating channels 53 are also advantageous during operation of the compressor arrangement in that heat can be removed via a coolant circulated in the channels 53. The temperature regulating system may be a standard cooling or heating system e.g. with heat exchangers, cooling bank, chiller, etc.

[0124] As mentioned, the hydraulic fluid volume in first and second chambers 4, 8, and thereby the first and second diaphragms 3, 7, are controlled independently of the reciprocating movement of the piston 13. This should be understood as the reciprocating movement of the piston 13 ensures required volume of hydraulic fluid in the supply chambers 11, 12. But due to the valves 50c, 50d this volume is not directly transferred to the fluid chambers 4, 8. This transfer is independently controlled by the valves 50c, 50d, valves which are controlled by the controller 49 together with the gas valves 23, 24, 27, 29 based on input from sensor 51 and maybe also from externals sensors and user input.

[0125] Typically, a diaphragm compressor 2, 6 comprise temperature sensors for establishing the temperature in the gas chamber and / or in the hydraulic fluid chamber. When this information is provided to the controller 49 in addition to information from the above-described sensors of the stacked head manifold 10 it is possible to optimizedcontrol of the flow of hydraulic fluid and thereby the movement of the diaphragm. The hydraulic fluid plate 18, 19 may comprise cooling channels, in addition to the temperature regulation channels 53 of the stacked head manifold 10. In such embodiment, it is easier to temperature regulate the hydraulic fluid in the supply chambers 11, 12. The temperature of the hydraulic fluid in the two illustrated supply chambers 11, 12 may be different.

[0126] As mentioned, the temperature of the hydraulic fluid may be controlled. The temperature of the hydraulic fluid in the supply chamber is reduced compared to the temperature of the hydraulic fluid in the hydraulic fluid chamber. This is because the heat from compressing the gas travels in the hydraulic plates which is physically not forming the supply chamber. Hence, as an example the chambers 4 and 11 are in two different enclosures (the plate 18 and manifold 10) and in addition, cooling can be provided in the manifold 10 to further reduced temperature thereof. This thermal control result in a better optimized compression.

[0127] One example of a hydraulic fluid can be found in European standards DIN 51524-2 and DIN 51524-3.

[0128] As the skilled person would know7the volume, temperature, pressure and density are the parameters that can be controlled when considering control of hydraulic fluid. The density is given by the choice of hydraulic fluid. The three other parameters are controlled according to the present invention by control of the fluid in the temperature regulation channels 53, the reciprocating movement of the piston 13, the valves 50c, 50d and the gas valves 23, 25, 27, 29. In an embodiment, this control is provided at least partly by the controller 49.

[0129] As illustrated, the piston 13 in this embodiment comprises piston protrusions 54 protruding from the circumference of the piston 13. These protrusions are moving in slots 55 provided in the cylinder housing 22. In this embodiment, it is these piston protrusions 54 that are physically closing / opening for the flow7of hydraulic fluid from the cylinder 14 to the supply chambers 11, 12.

[0130] By providing these protrusions relative to the openings of the channels 16, 17, the flow of hydraulic fluid can be timely controlled. This is also true if more than two diaphragm compressor heads are sharing the same piston 13. Then the piston 13 would have the same number of protrusions 54 as the number of diaphragm compressor heads.

[0131] The center of the openings to the channels 16, 17 are provided a third and fourth distance D3, D4 respectively from the end 14a of the cylinder housing 22. Hence, the location of the protrusions 54 on the cylinder 13 should be made according to these distancers and the length of the stroke of the piston. Note that the piston may comprise not illustrated piston rings.

[0132] Fig. 3b illustrates an alternative implementation of the invention. Otherwise, the principles are the same and thus the elements illustrated in fig. 3a may also be implemented in the embodiment illustrated in fig. 3b even though not illustrated.

[0133] In the implementation of fig. 3, the two compressor heads 2, 6 are oriented different i.e. the first compressor head 2 with gas inlet valve 23 away the crankcase 46 and the second compressor head 6 with gas inlet valve 27 towards from the crankcase 46. This implementation is advantageous in that it has the effect that the two compressor heads 2, 6, including plates 18, 19, 20, 21 can be identical and just turned 180 degrees to fit the stacked head manifold 10. Further, this is advantageous to keep the hydraulic channels as simple and as short as possible. Further, it also makes the two heads have identical flow paths, which is good in order to have equal performance on both heads 2, 6.

[0134] The optimal implementation of this embodiment requires that the supplychambers 11, 12 are located opposite each other in the stacked head manifold 10. This is to allow hydraulic fluid to enter the hydraulic fluid chambers 4, 8 at the inlet valves 23, 27, through the fluid paths 48. This is advantageous in that the hydraulic fluid can create a wave effect of the diaphragm pushing the gas in the gas chamber towards the outlet valves 25, 29. This is especially true when the gas and hydraulic chambers are oblong shaped.

[0135] It should be noted that the cut through illustrated in fig. 3b is made through the center of the compressor heads. Hence it is the center of the hydraulic plates that are illustrated and at the center of these plates fluid paths 48 are illustrated. It should be noted that in embodiments, a plurality of such fluid paths may be present. Such plurality of fluid paths may be provided in rows with an offset from the center of the plates. Between 5 and 25, such as between 10 and 20, such as 15 fluid paths may be provided in each row. The location of the fluid paths offset from the central plane is added to help move the diaphragm from the edge and towards the centre during a piston stroke pressurizing the gas in the gas chamber.

[0136] As illustrated, in this embodiment, the channels 16, 17 are somewhat larger in volume than the chambers 11, 12. The sizes of these volumes is determined as a compromise. The total volume of hydraulic fluid such as oil should be kept low to limit the effect of compressibility of the oil, which reduces the gas, such as hydrogen, flow from the compressor, and the channels must be wide enough to reduce flow resistance to an acceptable level.

[0137] Further it is noted that the walls of the chambers 11, 12 defined by the stacked head manifold 10 are declining towards the passage 48 to the hydraulic chambers. As mentioned above, the hydraulic plates may comprise a plurality of fluid paths 48. The supply chambers 11, 12 are designed to distribute the oil evenly along the oil cavity plates (also referred to as the hydraulic plate 18, 19), meaning that the depth is largest in the where all oil needs to flow through, and gradually declining to the end where only a small amount will flow.

[0138] Fig. 3b has another difference to the embodiment illustrated in fig. 3a. This is the cylinder housing 22 which in fig. 3b is divided in two parts 22a, 22b. These two parts are inserted into a through going bore in the stacked head manifold 10. In this way these two parts together with the piston 13 closes the through going bore. Between these two parts, the piston protrusions 54 are moving with the piston 13 in the cylinder slots 55. The piston is preferably cylindrical, with the protrusions 54 forming grooves for lip seals, and for a sliding bearing ring.

[0139] The cylinder housing parts 22a, 22b may comprise seals or the piston 13 may comprise piston rings (none of which are illustrated) to prevent hydraulic fluid from leaving the otherwise closed hydraulic fluid system. The cylinder housing parts 22a, 22b may be bolted to the stacked head manifold 10 and the cylinder housing parts 22a, 22b may close or probably more correctly create the cylinder slots 55.

[0140] The two cylinder housing parts 22a, 22b are at least partly forming the cylinder 14 in the embodiment illustrated in fig. 3b. Such two cylinder part design is advantageous over the one part cylinder housing 22 as illustrated in fig. 3a in that it is easier to manufacture and install. Further the two part design allows easier and more efficient machining / manufacturing of the manifold 10 and cylinder parts 22a, 22b which are to comply with the high pressures of the compressor arrangement. The compressor arrangement of the present invention is designed to pressurize gas to a pressure between lOPa and 1 lOPa such as between 35Pa and 95Pa, such as e.g. 90Pa. However, it should be mentioned that the compressor arrangement may be able to pressurize gas up to MOP A.

[0141] A passage 43 is illustrated in the cylinder part 22b. This passage is an example of a passage to allow leakage oil, that escapes into the cylinder part 22b, to escape from the cylinder part 22b. Non illustrate piping wall lead the oil e.g. to a drip tray.

[0142] The compressor arrangement 1 illustrated in fig. 4 comprise four diaphragm compressor heads 2, 6, 36, 37. A stacked head manifold 10 for these four diaphragm compressors is illustrated as the one described above and illustrated in fig. 1. Hence, in this embodiment one cylinder pressurize / circulates hydraulic fluid supply chambers for more than two diaphragm compressors. The stacked head manifold 10, in this embodiment, comprise fifth and sixth supply chambers with valves and sensors as described above.

[0143] On the other side of the crankcase 46 a similar stacked head manifold may be provided with two or more diaphragm compressor heads such as a third and a fourth diaphragm compressor 31, 35. In this case the additional stacked head manifoldcomprise an additional cylinder and piston which are provided on the other side of the crankcase 46 parallel to the illustrated stacked head manifold 10.

[0144] The stacked head manifold 10 is an example of the modularity of the compressor arrangement 1 of the present invention. Hence, the fluid plates illustrated in fig. 4 may be designed with the same outer dimensions as the fluid plates 18, 19 describe above. The bore for the cylinder housing in the stacked head manifold may simply be extended and thereby, the cylinder, piston and piston rod inside this cylinder housing may also simply be extended to facilitate the addition of two diaphragm compressor heads. It should be noted that an extended stacked head manifold 10 may be established by a first and a second stacked head manifold part which are mechanically connected with appropriate sealing therebetween. Such separation could be at the stipulated line

[0145] It should be mentioned that in principle, the two additional diaphragm compressors may in principle alternatively be located on the two free sides (upper and lower) of the part of the stacked head manifold 10 closest to the crankcase 46 (not illustrated). In principles, also more than six diaphragm compressors such as eight may be comprised by the compressor arrangement according to the principles of stacked diaphragm compressors according to the present invention. Either such additional compressor heads could be on a pentagonal or hexagonal shaped stacked head manifold 10 or on an extended stacked head manifold 10 as illustrated in fig. 4.

[0146] Hence in an embodiment, the diaphragm compressor arrangement 1 according to the present invention a first diaphragm compressor 2 comprises a first hydraulic fluid cavity 4 arranged to support, the first diaphragm 3 in a first extreme position, wherein the first diaphragm compressor 1 comprises a first gas cavity 5 arranged to support the first diaphragm 3 in a second extreme position, wherein the second diaphragm compressor 2 comprises a second hydraulic fluid cavity 8 arranged to support a second diaphragm 7 in a first extreme position, and wherein the second diaphragm compressor 2 comprises a second gas cavity 9 arranged to support the second diaphragm 7 in a second extreme position. Accordingly, it may be possible to implement the invention without the gas and hydraulic plates 18, 19, 20, 21. In thissituation, the cavities are made directly into the stacked head manifold 10 and into the pressure block of the compressors. This however is not at service friendly as the embodiment with gas and hydraulic fluid plates.

[0147] From the above it is now clear that the invention relates to a compressor arrangement 1 comprising a plurality of diaphragm compressors. At least two diaphragm compressors I, 2 are sharing the same hydraulic fluid system provided in a, to the at least two diaphragm compressors 1, 2, stacked head manifold 10. Since this stacked head manifold 10 comprise a cylinder 14, this cylinder 14 is also common to the at least two diaphragm compressors. The control of hydraulic fluid to the respective of the hydraulic fluid chambers 4, 8 of the at least two diaphragm compressors 1, 2 are control by a controller 49 independently via valves 50C, 50D positioned between the fluid chambers 4, 8 and a hydraulic fluid supply chamber 11, 12. The hydraulic fluid supply chambers 11, 12 are fluidly connected to the cylinder 14 and thus the amount / pressure of hydraulic fluid in the supply chambers 11, 12 is determined by the position of the piston 13 in the cylinder 14 together with the controlled stated of the valves 50C, 50D and also at least indirectly based on the controlled status of the gas inlet valves 23, 27 and gas outlet valves 25, 29.

[0148] The two or more diaphragm compressor may be controlled by the controller and be fluidly connected so as to constitute a plurality of stand-alone diaphragm compressors, duplex compressors, multi compression step compressors, etc.

[0149] The invention has been exemplified above with the purpose of illustration rather than limitation with reference to specific embodiments. Details of specific embodiment have been provided in order to understand the aim of the invention and can be combined where appropriate. Please note, that detailed descriptions of well-known systems, devices, circuits, and methods have been omitted so as to not obscure the description of the invention with unnecessary' details.List 30. Second outlet bore1, Compressor arrangement2. First diaphragm compressor 35 31. Third diaphragm compressor 3. First diaphragm4. First hydraulic fluid chamber 35. Fourth diaphragm compressor 5. First gas chamber 36. Fifth diaphragm compressor 6. Second diaphragm compressor 37. Sixth diaphragm compressor 7. Second diaphragm 408. Second hydraulic fluid chamber 43. Valve / sensor passages9. Second gas chamber 44. Valve block10. Stacked head manifold 45. Alignment pin11. 1. hydraulic fluid supply chamb. 46. Crankcase12. 2. hydraulic fluid supply chamb. 45 A. piston enclosure13. Piston B. crankshaft enclosure14. Cylinder14a. and 14b. distal ends of cyl. 48. Fluid paths15. Motor driven crank shaft 49. Controller16. First fluid channel 50 50. Regulation valve17. Second fluid channel A. Injection valve18. First hydraulic fluid plate B. Relief valve19. Second hydraulic fluid plate C. First supply chamber valve 20. First gas plate D. Second supply chamber valve 21. Second gas plate 55 51. Temperature and / or pressure sens.22. Cylinder housing22a and 22b 1. and 2. parts 53. Temperature regulating channels 23. First gas intake valve 54. Piston protrusion24. First intake bore 55. Cylinder slot25. First outlet valve 6026. First outlet bore D1-D4. 1.- 4. Distances27. Second gas intake valve28. Second intake bore29. Second outlet valve

Claims

Claims1. A diaphragm compressor arrangement comprising,at least one first diaphragm compressor (2) including a first diaphragm (3) arranged between a first hydraulic fluid chamber (4) and a first gas chamber (5), wherein said first diaphragm (3) is substantially flat in a first diaphragm plane when said first diaphragm (3) is in neutral position,at least one second diaphragm compressor (6) including a second diaphragm (7) arranged between a second hydraulic fluid chamber (8) and a second gas chamber (9), wherein said second diaphragm (7) is substantially flat in a second diaphragm plane when said second diaphragm (3) is in neutral position,a stacked head manifold (10) comprising a first hydraulic fluid supply chamber (11), a second hydraulic fluid supply chamber (12) and a cylinder (14)wherein said first hydraulic fluid supply chamber (11) is in fluid communication with said first hydraulic fluid chamber (4),wherein said second hydraulic fluid supply chamber (12) is in fluid communication with said second hydraulic fluid chamber (8), andwherein said first and second hydraulic fluid supply chambers (11, 12) are furthermore in fluid communication with said cylinder (14), anda piston (13) mechanically connected to a crankshaft (15), said crankshaft (15) is configured for linear actuation of said piston (13) in said cylinder (14).

2. The diaphragm compressor arrangement according to claim 1, wherein said stacked head manifold (10) is a common compressor housing manifold.

3. The diaphragm compressor arrangement according to any one of claims 1-2, wherein said cylinder (14) and said first hydraulic fluid chamber (4) is in fluid communication via a first fluid channel (16), wherein said cylinder (14) and said second hydraulic fluid chamber (8) is in fluid communication via a second fluidchannel (17), and wherein said first fluid channel (16) and said second fluid channel (17) are displaced relative to each other along a longitudinal axis of said cylinder (14),4. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first fluid channel (16) and said second fluid channel (17) are provided as conduits arranged inside said stacked head manifold (10) and / or in said cylinder housing (22).

5. The diaphragm compressor arrangement according to any one of the preceding claims, wherein the length of said first fluid channel (16) is different from the length of said second fluid channel (17).

6. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first hydraulic fluid supply chamber (11) is having a fixed volume.

7. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said second hydraulic fluid supply chamber (12) is having a fixed volume.

8. The diaphragm compressor arrangement according to any one of the preceding claims, wherein the volume of said hydraulic fluid supply chambers (11, 12) is independent of the position of said piston (13) in said cylinder (14).

9. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first hydraulic fluid supply chamber (11) is arranged in said stacked head manifold (10) between said first compressor head (2) and the two distal ends (14a, 14b) defining said cylinder (14).

10. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said second hydraulic fluid supply chamber (12) is arranged in said stacked head manifold (10) between said second compressor head (6) and the two distal ends (14a, 14b) said cylinder (14).

11. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said stacked head manifold comprises integrated temperature regulating channels (53).

12. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said stacked head manifold (10) comprises control valves (50C, 50D) configured for controlling flow of hydraulic fluid in said first and second hydraulic fluid channels (16, 17).

13. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first hydraulic chamber (4) is provided in a first hydraulic fluid plate (18) and wherein said second hydraulic chamber (8) is provided in a second hydraulic fluid plate (19).

14. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first gas chamber (5) is provided in a first gas plate (20) and wherein said second gas chamber (9) is provided in a second gas plate (21).

15. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first diaphragm compressor (2) and said second diaphragm compressor (6) are arranged opposite each other on opposite sides of said cylinder (14).

16. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said cylinder (14) is arranged substantially in the middle between said first diaphragm (3) and said second diaphragm (7).

17. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first diaphragm compressor (2) is pressed against said stacked head manifold (10) and wherein said second diaphragm compressor (6) is pressed against said stacked head manifold (10) by means of through going bolts extending between said first diaphragm compressor (2) and said second diaphragm compressor (6).

18. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said cylinder (14) is arranged in a monolithic cylinder housing (22) and wherein said cylinder housing (22) is arranged in a slot in said stacked head manifold (10) between said first diaphragm compressor and said second diaphragm compressor.

19. The diaphragm compressor arrangement according to any one of the preceding claims, wherein a first gas intake valve (23), arranged at the bottom of a first intake bore (24), is connected to said first gas chamber (5), wherein a first outlet valve (25), arranged at the bottom of a first outlet bore (26), is connected to said first gas chamber (5), wherein said first intake bore (24) and said first outlet bore (26) are substantially perpendicular to said first diaphragm plane, and wherein a second gas intake valve (27), arranged at the bottom of a second intake bore (28), is connected to said second gas chamber (5), wherein a second outlet valve (29), arranged at the bottom of a second outlet bore (30), is connected to said second gas chamber (9), wherein said second intake bore (28) and said second outlet bore (30) are substantially perpendicular to said second diaphragm plane.

20. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said piston (13) comprise a first piston protrusion (55) and a second piston protrusion (55) extending from the circumference of said piston (13).

21. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first piston protrusion (55) is located a third distance (D3) from an end (14A) of said cylinder housing (22) and wherein said second piston protrusion (55) is located a fourth distance (D4) from said end (14A) of said cylinder housing (22), wherein said third distance (D3) and said fourth distance (D4) are different.

22. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first and second piston protrusions (54) are moving with said piston (13 ) in first and second slots (55) provided in said cylinder housing (22).

23. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said linear actuation of said piston (13) allow movement of said piston(13) in a direction substantially parallel with said first diaphragm plane and with said second diaphragm plane.

24. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first diaphragm plane and said second diaphragm plane are parallel.

25. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said crankshaft (15) is arranged to facilitate reciprocating movement of said piston (13) in said cylinder (14) at least 300 times per minute.

26. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said diaphragm compressor arrangement (1) is a high-pressure diaphragm compressor arrangement arranged for pressurising a gas in said first gas chamber (5) of said first diaphragm compressor (2) and pressurising a gas in said second gas chamber (9) of said second diaphragm compressor (6) to a pressure between 10 and 300 MPa, preferably between 20 and 200 MPa, and most preferred between 30 and 130 MPa.

27. The diaphragm compressor arrangement according to any one of the preceding claims, wherein the first compressor head (2) and the second compressor head (6) are identical and wherein the first compressor head (2) is mounted to the stacked head manifold (10) with gas intake valve (23) towards the crankcase (46) and wherein the second compressor head (6) is mounted to the stacked head manifold (10) with gas outlet valve (29) towards the crankcase (46).

28. The diaphragm compressor arrangement according to any one of the preceding claims, wherein the volume of hydraulic fluid in said first and second fluid chambers (4, 8) are controlled independently from the location of said piston (13) in said cylinder (14) by first and second supply chamber valves (50c, 50d).

29. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first hydraulic fluid chamber (4), said first fluid channel (16), said first hydraulic fluid supply chamber (11), said second hydraulic fluid chamber (8), saidsecond fluid channel (17), said second hydraulic fluid supply chamber (12) and said cylinder (14) constitute a main closed hydraulic fluid system.

30. The diaphragm compressor arrangement according to any one of the preceding claims, wherein at least a quantity of hydraulic fluid comprised by said first hydraulic fluid supply chamber (11) travels through said first fluid channel (16), said cylinder (14) and said second fluid channel (17) to said second hydraulic fluid chamber (12) during each stroke of said piston (13).

31. The diaphragm compressor arrangement according to any one of the preceding claims, wherein an end of said first fluid channel (16) allowing flow of hydraulic fluid between said cylinder (14) and said first fluid channel (16) is positioned a first di stance (DI) from an end (14 A) of said cylinder (14),wherein an end of said second fluid channel (17) allowing flow of hydraulic fluid between said cylinder (14) and said second fluid channel (17) is positioned a second distance (D2) from said end (14A) of said cylinder (14), andwherein said first distance (DI) and said second distance (D2) are different.

32. The diaphragm compressor arrangement according to any one of the preceding claims, wherein an oil injection system comprising an injection valve (50A) discontinuously supplying oil from a reservoir to said main closed hydraulic fluid system.

33. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said main closed hydraulic fluid system comprise a relief valve (50B).

34. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said diaphragm compressor arrangement (1) further comprises,at least one third diaphragm compressor (31) including a third diaphragm arranged between a third hydraulic fluid chamber and a third gas chamber, wherein said third diaphragm is substantially flat in a third diaphragm plane when said third diaphragm is in a neutral position,at least one fourth diaphragm compressor (35) including a fourth diaphragm arranged between a fourth hydraulic fluid chamber and a fourth gas chamber, wherein said fourth diaphragm is substantially flat in a fourth diaphragm plane when said fourth diaphragm is in a neutral position,an additional stacked head manifold comprising a third hydraulic fluid supply chamber, a fourth hydraulic fluid supply chamber and an additional cylinderwherein said third hydraulic fluid supply chamber is in fluid communication with said third hydraulic fluid chamber,wherein said fourth hydraulic fluid supply chamber is in fluid communication with said fourth hydraulic fluid chamber, andwherein said third and fourth hydraulic fluid supply chambers are furthermore in fluid communication with said additional cylinder, andan additional piston also mechanically connected to said crankshaft, wherein said crankshaft is furthermore configured for linear actuation of said additional piston in said additional cylinder.

35. The diaphragm compressor arrangement according to any one of the preceding claims, wherein the direction of said linear actuation of said piston (13) and the direction of said linear actuation of said additional piston is substantially parallel.

36. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first diaphragm compressor (2), said second diaphragm compressor (3), and said cylinder (14) are arranged on a first side of said crankshaft (15), wherein said third diaphragm compressor (31), said fourth diaphragm compressor (32), and said additional cylinder are arranged on a second side of said crankshaft (15) and wherein said first side is opposite said second side.

37. The diaphragm compressor arrangement according to any one of the preceding claims, wherein said first diaphragm compressor is substantially identical to said third diaphragm compressor, wherein said second diaphragm compressor is substantiallyidentical to said fourth diaphragm compressor, and wherein said cylinder is substantially identical to said additional cylinder.

38. Use of a diaphragm compressor arrangement according to any of the preceding claims for pressurising hydrogen in a hydrogen fuelling station.

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