EP2295786B1 - Connection arrangement - Google Patents

Description

The invention relates to a connection arrangement with a pressure accumulator according to the preamble of the independent claim. The invention further relates to a large diesel engine with such a with such a connection arrangement.

In devices in which fluids, in particular liquids, must be conducted under high pressure, it is necessary between the individual components compounds that withstand the high pressure and also must be tight. As an example may be mentioned here large diesel engines, which may be configured as two-stroke or four-stroke engines, and often as drive units for ships or in stationary operation, e.g. be used to drive large generators for generating electrical energy.

In modern large diesel engines, there are two media in particular, which are transported under very high pressures, on the one hand, the fuel, which is transported to the injection nozzles with a pressure of up to more than 1000 bar, and on the other a hydraulic medium, commonly referred to as servo oil becomes. The hydraulic medium is used for example hydraulic actuation of the exhaust valves. These media are conveyed by pumps in accumulators, which are designed as pressure pipes and often extend along the entire cylinder area. From these pressure accumulators, which are also referred to as accumulators, the medium passes to the injectors or to the control or actuating devices for the hydraulic components.
The connection between the pressure accumulators and the devices that require the medium are often based on screwed connections, in which the device is screwed directly onto the wall of the pressure accumulator, or on high pressure lines, which are pressed by a thread sealingly into a corresponding outlet bore of the pressure accumulator. Also, welded or soldered connections are known.
The object of the invention is to propose another, structurally simple and reliable high-pressure connection with which a pressurized fluid can be conducted from a pressure accumulator to a device. Furthermore, such a connection arrangement should be proposed. In particular, the high-pressure connection should be suitable for use in large diesel engines.
The objects of the invention solving these objects are characterized by the features of the independent claim.

In this case, the active surface means the vertical projection of the respective end face onto that plane which is perpendicular to the longitudinal axis, that is to say the surface which is decisive for the force exerted by the fluid on the end face. Since the effective area for the second end surface is greater than for the first end surface, but the pressure exerted by the fluid is substantially equal on both end surfaces, a larger force acts on the second end surface by the fluid than on the first end surface by the fluid the high-pressure connection is pressed with its first end surface sealingly into the seat. Thus, a high-pressure-tight connection can be realized, which is sealed by the pressurized fluid. In principle, neither screws nor welds are necessary for this sealing function. As mentioned, the first end surface is designed as a conical surface or truncated cone surface. With this geometry of the first end surface, a particularly good sealing effect can be achieved at the connection to the pressure accumulator.
Advantageously, the second end surface is designed as a circular surface. This is on the one hand structurally simple and maximizes the effective area of the second end face for a given diameter of the second end face.

In this connection arrangement, the seal between the high-pressure connection and the pressure accumulator is effected mainly by the pressure of the fluid on the second end surface. Since their effective area is greater than the effective area of the first end surface, results in a force which presses the first end surface sealingly against the seat surface of the pressure accumulator.

An important application in practice is that the pressure accumulator is designed as a pressure tube.

It is structurally provided that the device is fastened laterally to the pressure accumulator with respect to the normal position of use. This makes it possible to avoid pressure surges that are in the operating state of the device occur, for example, by opening, closing or switching valves, lead to a force in the pressure tube.

A further advantageous measure is when a holder is provided which surrounds the pressure accumulator, wherein the high-pressure connection is attached to the holder. Thus, it is possible to avoid screwing the high pressure connection directly in the wall of the pressure accumulator.

Preferably, the second end surface of the high pressure connection is disposed in a bore of the device. By this measure, it is possible that the fluid can exert a particularly good pressure on the second end surface.

Advantageously, the high-pressure connection is received without thread from the device, so that the force can be optimally transmitted from the second to the first end face.

In a preferred application, the pressure accumulator is a pressure tube for hydraulic medium or fuel in a large diesel engine.
The invention further proposes a large diesel engine with a connection arrangement according to the invention.
In a large diesel engine according to the invention, the pressure accumulator is a pressure tube for hydraulic medium or fuel, wherein the pressure tube is supported by the device and wherein the pressure tube is fixed laterally relative to the normal position of use of the device. In this way, it is achieved that pressure surges in the device are derived in their support and do not lead to a significant force into the pressure tube.

A particularly relevant application in practice is when the device is a valve control unit for the hydraulic control of an exhaust valve.

Further advantageous measures and preferred embodiments of the invention will become apparent from the dependent claims.

Fig. 1:

ein erstes Ausführungsbeispiel einer erfindungsgemässen Verbindungsanordnung mit einem Ausführungsbeispiel der Hochdruckverbindung,

Fig. 2:

ein Ausführungsbeispiel eines erfindungsgemässen Grossdieselmotors mit einem zweiten Ausführungsbeispiel einer erfindungsgemässen Verbindungsanordnung, und

Fig. 3:

eine Schnittdarstellung des zweiten Ausführungsbeispiel entlang der Schnittlinie III-III in Fig. 2.

In the following the invention will be explained in more detail by means of embodiments and with reference to the drawing. In the schematic, not to scale drawing show partly in section:

Fig. 1:

A first embodiment of an inventive connection arrangement with an embodiment of the high-pressure connection,

Fig. 2:

an embodiment of a large diesel engine according to the invention with a second embodiment of a connection arrangement according to the invention, and

3:

a sectional view of the second embodiment along the section line III-III in Fig. 2 ,

Fig. 1 shows in a sectional view of a first embodiment of a connection arrangement according to the invention, which is provided overall with the reference numeral 10, and which includes an embodiment of the high-pressure connection, which is generally designated by the reference numeral 1. The connection assembly 10 comprises a pressure accumulator 2 for a fluid and an only indicated device 3, which is operated by means of the pressurized fluid.

The fluid may be any gaseous or liquid medium used in pressurized working processes, such as hydraulic oil or servo oil for hydraulically actuating or controlling pistons, valves or the like, fuel for injection into the cylinder of an internal combustion engine, or water must be transported under pressure.

The device 3 may be any device operated by means of a pressurized fluid, for example a control valve, a hydraulically operated piston, a pump, or a pressure line carrying the fluid.

The pressure accumulator 2, for example, tubular, in particular cylindrical, be designed as a pressure tube with a cylinder axis L, as well as the pressure accumulators, which are used today in common rail systems. The pressure accumulator 2 comprises a wall 21, the inside of which has a storage space 22 for the pressurized fluid. The pressure accumulator 2 comprises at least one connecting bore 23, which extends from the storage space 22 radially outwardly through the wall 21, and which opens into a seat surface 24. The seat 24 is conical.

Typically, a plurality of connecting bores 23 are provided in the tubular pressure accumulator 2 of a common rail system, which are shown in relation to the cylinder axis L according to ( Fig. 1 ) are arranged one behind the other. Since it is sufficient for the understanding, the following explanations are limited to only one connection hole 23.

The high-pressure connection 1 comprises a body 11 which extends in the direction of a longitudinal axis A from a first end surface 12 to a second end surface 13. The first end surface 12 is configured for sealing engagement with the seat surface 24. In the present embodiment, the first end surface 12 is designed as a conical surface or as a frustoconical surface. In this case, the associated cone angle of the first end face 12 can be the same size as the cone surface belonging to the seat surface 24 or-depending on the material-also somewhat smaller.

Fig. 1 It is understood that in the operating state, the high-pressure connection 1 is pressed with its first end face 12 in the seat surface 24, so as to create a high-pressure-tight connection between the pressure accumulator 2 and the high-pressure connection 1 , If the cone angle associated with the first seat surface 12 is undersized compared to the seat surface 24, the first end surface 12 deforms in the operating state by the prevailing pressure and adapts to the seat surface 24.

The first end face 12 has an inlet opening 14, through which the fluid from the storage space 22 of the pressure accumulator 2 can flow into the high-pressure connection 1. From the inlet opening 14 extends a centrally disposed passage bore 15 in the direction of the longitudinal axis A up to an outlet opening 16, which is provided in the second end face 13. The second end face 13 is configured in this embodiment as a circular surface or as an annular surface.

The second end face 13 is designed such that it can be received by the device 3. The device 3 has a cavity or bore 31 which is bounded by a wall 32, and which the second end surface 13 receives. According to illustration, below the second end surface 13, the body 11 of the high-pressure connection 1 has a groove which extends over the entire circumference, and in which a sealing element 17, for example an O-ring, inserted between the wall 32 and the body 11 seals.

The first and second end surfaces 12 and 13 each have an effective area. This means the effective area over which the pressure which acts on the respective end face 12, 13 can produce a force in the direction of the longitudinal axis-that is to say upward or downward as shown. The active surface is thus the vertical projection of the respective end face 12, 13 on the plane which is perpendicular to the longitudinal axis A. For the first end face 12, the effective area is the same size as the cross-sectional area at the in Fig. 1 indicated by the arrow W1 point. For the second end face 13, the effective area is the same size as the second end face 13.

According to the invention, the effective area of the second end face 13 is greater than the effective area of the first end face 12.

In the operating state, the pressurized fluid flows from the storage space 22 of the pressure accumulator 2 through the connection bore 23 and the passage bore 15 in the part of the bore 31 of the device 3, which is located above the second end face 13 as shown. From there, the fluid may, for example, flow through a channel 33 in order to be available in the device 3.

The second end surface 13 is acted upon by the fluid at substantially the same pressure, which also prevails in the storage space 22. Since the second end face 13 has an effective area which is larger than the effective area of the first end face 12, in any case a result in the direction of the longitudinal axis - according to the drawing down - directed force, which presses the first end surface 12 sealingly against the seat surface 24. Thus, a sealing function caused by the pressure of the fluid can be achieved.

For this seal is in principle no screwing and no other attachment, z. B. by welding or soldering needed. However, it is understood that additional screws or other fastening or guiding means may be provided, for example, to guide the high-pressure connection 1 in the direction of the longitudinal axis A or to prevent tilting of the high-pressure connection 1 or to achieve a primary seal. This will be explained by way of example with reference to the second embodiment.

In the second embodiment, reference is made to the important application in practice of a large diesel engine. In modern large diesel engines, the fuel injection, the gas exchange, possibly the water injection and auxiliary system with common rail systems are operated. In this case, by means of pumps the respective fluid, for. As the fuel for injection, a hydraulic medium such as servo oil for actuating the exhaust valves or a working medium for controlling the injection under high pressure in a pressure accumulator promoted, which is also referred to as an accumulator. With the pressurized fluid from the respective accumulator all cylinders of the internal combustion engine are then supplied or actuated the valves and the fuel injectors. Usually, the accumulators are each designed as a tube-like, closed at both ends components that extend approximately at the level of the cylinder heads along the engine.

The highest pressures typically occur in the common rail fuel injection system. In the associated pressure accumulator, the pressure can be up to 2000 bar, for example. In the pressure accumulator of the common rail system for the actuation of the exhaust valves, the pressure of the hydraulic medium (eg servo oil) can be up to 300 bar.

Fig. 2 shows in a partially schematic representation of those essential for the understanding of the invention parts of an embodiment of a large diesel engine according to the invention, which is provided overall with the reference numeral 100. In particular, this embodiment is a slow-current, longitudinally-flushed 2-stroke large diesel engine 100 with a cross-head drive. The large diesel engine 100 comprises a second exemplary embodiment of a connection arrangement 10 according to the invention, which in FIG Fig. 3 can be seen in a sectional view. The section is taken along the section line III-III in Fig. 2 ,

Functionally identical or equivalent parts are in Fig. 2 or in Fig. 3 - provided with the same reference numerals as in Fig. 1 , All explanations related to Fig. 1 and the first embodiment, apply in an analogous or analogous manner also for the second embodiment.

The large diesel engine 100 usually includes a plurality of cylinders 101, of which in Fig. 1 only one can be seen. In each cylinder 101, a piston 102 is arranged to be movable back and forth. The piston 102 is connected via a piston rod 103 with a crosshead, not shown, which in turn is connected via a push rod with a crankshaft (not shown).

On each cylinder, an exhaust valve 104 is provided, which is hydraulically actuated in a conventional manner. This actuation takes place via a common rail system which comprises the second exemplary embodiment of the connection arrangement 10 according to the invention. The common rail system for the control of the exhaust valve 104 includes the pressure accumulator 2, which is designed as a pressure tube for the hydraulic medium.

The device 3 is here a valve control unit 3, which via the high-pressure connection 1 (see Fig. 3 ) is connected to the connection bore 23 of the pressure accumulator 2. The second end face 13 of the high-pressure connection 1 is analogous to that in FIG Fig. 1 shown arranged in the bore 31 of the valve control unit 3. In this case, the high-pressure connection 1 is received without thread from the valve control unit. The valve control unit 3 comprises an electrically piloted main control valve 35 and an electromagnetic pilot valve 36, which is controlled by a control unit 105 via a signal line 106. As soon as the pilot control valve 36 opens the main control valve 35, the hydraulic medium can flow from the pressure accumulator 2 through a pressure line 107 to the outlet valve 104 in order to open it.

Furthermore, a pump 108 is provided which conveys the hydraulic medium from a reservoir, not shown, via a line 109 into the pressure accumulator 2.

In Fig. 2 If only one valve control unit 3 is shown, it is understood, however, that for each cylinder 101 a respective valve control unit 3 is provided which is connected in each case via a high-pressure connection 1 to a separate connection bore 23 of the pressure accumulator 2.

The accumulator 2 is connected via a holder 4 with the valve control unit 3 (see also Fig. 3 ). The holder 4 surrounds the pressure accumulator 2 in the manner of a pipe clamp. For attachment of the high pressure connection 1, a flange 18 is provided on the body 11, which is provided with two unthreaded holes for receiving first screws 41. By means of the first screws 41, which engage in threaded holes in the holder 4, the high-pressure connection 1 is attached to the holder 4, namely here screwed. In this case, the first end surface 12 is pressed into the seat surface 24, so that already a seal between the high-pressure connection 1 and the pressure accumulator 2 takes place. As a result, at least one primary seal is achieved.

For connecting the high-pressure connection 1 with the valve control unit 3, the second end face 13 is inserted into the bore 31, wherein the designed as an O-ring sealing member 17 between the wall 32 of the bore 31 and the body 11 of the high-pressure connection 1 seals. Then, the valve control unit 3 is mounted by means of second screws 42 to the Hälterung 4 and tightened.

In the operating state, the hydraulic medium also acts on the second end face 13 of the high-pressure connection, which is located in the bore 31 of the valve control unit 3 (see also FIG Fig. 1 ) is arranged, with pressure. Since the effective area of the second end face 13 is greater than the effective area of the first end face 12, the high-pressure connection 1 is pressed with its first end face 12 sealingly into the seat surface 24 of the pressure accumulator 2.

The entire support of the connection assembly 10 comprising the pressure accumulator 2, the high-pressure connection 1, the valve control unit 3 and the holder 4 is preferably carried out only via the valve control unit 3. Since - as already mentioned - a plurality of valve control units 3 are provided supported the connection assembly 10 over several locations. The valve control unit 3 is fixedly attached to the large diesel engine 100 or to a support 5 provided therefor, as shown in FIG Fig. 3 is indicated. The pressure accumulator 2 is with respect to its normal position of use, which the representation in Fig. 2 and Fig. 3 corresponds, mounted on the bracket 4 laterally adjacent to the valve control unit 3. The designed as a pressure tube pressure accumulator 2 has no direct support on the engine or on the motor housing, but is supported only on the valve control units 3.

It is state of the art to mount the pressure accumulator firmly on the engine, for example on a support, in such a way that the connection bores point vertically upwards relative to the normal position of use. The devices 3 and the valve control units 3 are then located on top of the pressure accumulator. For this purpose, the accumulator must have on its upper side a flat surface for mounting the valve control units, which are fixed with screws on this flat surface. These screws then engage in the wall of the accumulator, that is, the wall of the accumulator must be provided with threaded holes. In this vertical arrangement, the dynamic forces that occur, for example, when switching the valve control units go through the pressure accumulator in the support. The entire assembly is supported via the pressure accumulator.

• So werden die dynamischen Kräfte, die beispielsweise beim Schalten der Ventilsteuereinheiten 3 auftreten, im wesentlichen nicht in den Druckspeicher 2 eingeleitet, sondern werden von der Ventilsteuereinheit 3 direkt auf die Auflage 5 übertragen. Dies reduziert die mechanische Belastung des Druckspeichers 2 deutlich.

Compared to this prior art, the arrangement of the accumulator 2 has laterally on the device 3 and the valve control unit 3, some advantages:

• Thus, the dynamic forces that occur, for example, when switching the valve control units 3, essentially not introduced into the pressure accumulator 2, but are transmitted from the valve control unit 3 directly to the support 5. This significantly reduces the mechanical load on the pressure accumulator 2.

A further advantage is that due to the holders 4, the pressure accumulator 2 no longer has to have a plane surface on its outside, which on the one hand increases the mechanical stability and on the other hand simplifies production.

Furthermore, the wall 21 of the accumulator 2 is free of holes and free of tapped holes, because both the first mounting screws 41 and the second mounting screws 42 engage in the holder 4, but not in the wall 21 of the pressure accumulator 2. This increases the mechanical stability the accumulator 2 quite considerably, which can lead to the pressure accumulator 2 can be made despite the same operating pressure with a thinner wall 21.

Claims (9)

1. A connection arrangement having a pressure reservoir (2) for a pressurized fluid, an apparatus (3) which is operated by means of the fluid and a high pressure connection (1) through which the fluid can arrive at the apparatus (3) from the pressure reservoir (2), wherein the pressure reservoir (2) is made as a pressure pipe and has at least one connection bore (23) which opens into a seating surface (24), wherein the apparatus (3) is laterally fastened to the pressure reservoir (2) made as a pressure pipe with regards to the normal position of operation., so that the support of the pressure reservoir (2) is effected only via the apparatus (3), wherein the high pressure connection includes a body (11) which extends in the direction of a longitudinal axis (A) from a first end face (12) to a second end face (13), wherein the first end face (12) is adapted to sealingly cooperate with the seating surface (24) and has an inlet opening (14) and wherein the second end face (13) has an outlet opening (16) which is connected to the inlet opening (14) via a passage bore (15), wherein the high pressure connection (1) contacts the seating surface (24) with its first end face (12) and is received with its second end face (13) by a cavity of the apparatus (3), such that the fluid can flow from the pressure reservoir (2) via the passage bore (15) of the high pressure connection (1) into the apparatus (3), wherein the second end face (13) has an active surface for the fluid which is larger than the active surface of the first end face (12), wherein the first end face (12) is made as a conical surface or a frustoconical surface extending in the direction away from the second end face (13) with tapering decreasing diameter.
2. A connection arrangement in accordance with any one of the preceding claims, wherein the second end face (13) is made as a circular surface.
3. A connection arrangement in accordance with any one of claims 1-2, in which a mounting (4) is provided which surrounds the pressure reservoir (2), wherein the high pressure connection (1) is attached to the mounting (4).
4. A connection arrangement in accordance with any one of claims -1-3, in which the second end face (13) of the high pressure connection (1) is arranged in a bore (31) of the apparatus (3).
5. A connection arrangement in accordance with any one of the preceding claims,, in which the high pressure connection (1) is received by the apparatus (3) without a thread.
6. A connection arrangement in accordance with any one of the preceding claims,, in which the pressure reservoir (2) is a pressure pipe for a hydraulic medium or fuel in a large diesel engine (100).
7. A large diesel engine having a connection arrangement in accordance with any one of the preceding claims,.
8. A large diesel engine in accordance with claim 7, in which the pressure reservoir (2) is a pressure pipe for a hydraulic medium or a fuel, wherein the pressure pipe is supported via the apparatus (3) and wherein the pressure pipe is laterally fastened to the apparatus (3) with regards to the normal position of operation.
9. A large diesel engine in accordance with claim 7 or 8, wherein the apparatus (3) is a valve control unit for the hydraulic actuation of an outlet valve (104).

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