KR101730122B1 - A large two-stroke diesel engine and a supporting plate structure for connection between an engine main structure and an exhaust gas receiver - Google Patents

Abstract

A support plate structure (100) for connection between an engine main structure (1) and an exhaust gas receiving portion (16), the plate structure (100) comprising:
Two opposing steel plates (110, 115) each having a first end and a second end (117, 118);
At least one spacer 130 for maintaining the two plates 110 and 115 in spaced relation so that the plates 110 and 115 at a location 116 between the first and second ends 117 and 118, At least one spacer (130) disposed between the first and second spacers; And
A connector (102,105) at the first end (117) and the second end (118), wherein the two steel plates (110,115) are spaced apart from one another at the ends (117,118) Wherein the at least one spacer 130 is spaced apart from the two steel plates 110 and 115 by a greater second spacing S1 between the spacers 130, ).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large two-stroke diesel engine and a support plate structure for connection between an engine main structure and an exhaust gas receiving portion,

The present invention relates to a large two-stroke diesel engine having an engine main structure and a support plate structure for connection between the engine main structure and the exhaust gas receiving portion.

The exhaust gas receiving portion of a large two-stroke diesel engine receives high temperature (approximately 450 ° C) exhaust gas at pressures of up to 4 bar from each cylinder as a component under high load.

Because of the large size of the exhaust gas receiving portion (which can be significantly longer than 10 m and can have a diameter of up to 2 m) and a high operating temperature, the thermal expansion of the exhaust gas receiving portion is very prominent, And an exhaust gas receiving portion that can be divided into two or more housing portions separated by bellows to absorb the dimensional change caused. The finished exhaust gas receiving portion and any portions thereof are covered with a thick layer of the heat insulating material so that the temperature of the outer surface of the exhaust gas receiving portion is substantially lower than the exhaust gas temperature inside the exhaust gas receiving portion. The safety requirement requires that the temperature of the outer surface of the exhaust gas receiving portion be lower than 220 占 폚 so that the engine fuel or other oil is not exposed to the engine portions such that the temperature is so high as to inadvertently contact and ignite the exposed engine portions . In practice, the outer surface of the exhaust gas receiving portion is well insulated so that its surface temperature is kept below 150 캜.

The exhaust gas reservoirs are supported in the middle or at one end of the longitudinal expansion by a rigid main support. Some of the flexible supports are distributed along the length of the exhaust gas receiver on either side of the rigid support and connect the exhaust gas receiver to the engine housing or engine main structure. The flexible supports are typically formed by a single plate that allows substantial movement in the longitudinal direction of the exhaust gas receiver, and such longitudinal movement is necessary to compensate for the thermal expansion / contraction of the exhaust gas receiver when the exhaust gas receiver is heated / cooled .

In addition to the load of heat and pressure, the vibrational motion of the engine shakes the structure further to further increase the mechanical load on the exhaust gas receiving portion. One particular problem is the vibration of the flexible supports, which creates a particularly undesirable noise. There have been attempts to solve such problems by welding reinforcing ribs to the flexible supports to reduce the natural frequency, but cracks have occurred where the ribs have been welded to the support and the overall problem has not been solved completely satisfactorily.

In this context, it is an object of the present invention to provide a support plate structure that at least partly solves this problem, which is achieved by increasing the lowest natural frequency of the flexible support without compromising the need for a reliable and durable plate structure .

This object is achieved by providing a flexible support as a pair of flexible steel plates arranged to extend transversely in the longitudinal direction, wherein the steel plates are spaced at intervals (S1, S2, S3) whose major faces are changed between the upper and lower ends And at least one spacer is disposed between the steel plates at a location between the top and bottom so as to hold the steel plates in a larger spacing S1 in the spacers.

Other objects, features, advantages and characteristics of the exhaust gas receiving portion according to the present invention will become apparent from the detailed description.

In the following detailed description of the present invention, the present invention will be described in more detail with reference to the embodiments shown in the drawings.
1 is a view of a long side of a large two-stroke engine with a plate structure according to an embodiment of the present invention.
Fig. 2 is a view of the rear end of the engine shown in Fig. 1. Fig.
3A is a perspective view of an end portion of an exhaust gas receiving portion supported by a plate structure according to an embodiment of the present invention.
Figure 3b is a side view of the embodiment of Figure 3a.
Figure 3c is a top view of the embodiment of Figure 3a.
4 is a schematic side view when the plate structure is mounted, and the exhaust gas receiving portion is in a cold state.
Figure 5 schematically shows a flash image of the plate structure vibrating during operation of the engine, ignoring accumulation.
6 is a schematic diagram showing test results for comparing how the lowest natural frequency of the plate structure can be changed.

1 and 2 show the engine main structure 1 of a large two-stroke diesel engine as a side view and a rear view, respectively. The engine is a uniflow low-speed 2 stroke crosshead diesel engine of the crosshead type, which may be the engine of the propulsion system of the ship or the power plant . These engines typically have from three to a maximum of fourteen engines that are in a row. The engine is constructed from a bedplate 2 having a main bearing for the crankshaft (only the flywheel 3 attached to the end of the crankshaft is shown). The bed plate 2 may be made into a single part or may be divided into sections of appropriate size depending on the manufacturing facility.

The A-shaped frame box 4 of the welded design is mounted on the bed plate 2. On the exhaust side, the frame box 4 has a relief valve for each cylinder, whereas the frame box 4 on the camshaft side has a large hinged door for each cylinder, Respectively. The crosshead guide planes (not shown) are incorporated into the frame box 4.

The cylinder frame 5 is mounted on the upper part of the frame box 4. A staybolt (not shown) connects the bed plate 2, the frame box 4 and the cylinder frame 5 and holds the structure together. The cylinder frame (5) holds the individual cylinders (6). Each of the cylinders of the engine is connected to the inlet of the exhaust gas receiving portion 16 by an exhaust passage. The cylinder frame 5 forms a scavenge air space together with a cylinder liner 6. The scavenging receptacle 9 is bolted to the cylinder frame 5. A piston (not shown) is accommodated in each of the cylinder liner 6. A piston rod (not shown) connects the bottom of the piston to the top of the crosshead (not shown). The cylinder liner 6 is held by the cylinder frame 5.

The engine is provided with one or more turbochargers (10), and the turbocharger is disposed at the side or rear end of the engine. The cylinders are uniflow type and have scavenge ports (not shown) located in an air box from which scavengers 10 are fed to the scavengers 10. The air intake to the turbocharger 10 is generated directly from the engine room through the intake muffler (not shown) of the turbocharger. From the turbocharger 10, air flows to the scavenge ports of the cylinder liner 6 through the air cooler 11, the charging air pipe 12 and the scavenging receiver 9. The engine is equipped with an auxiliary blower (13) driven by electricity. The auxiliary blower assists the turbocharger compressor under low and medium load conditions.

An exhaust valve (not shown) is centrally mounted at the top of the cylinder in the cylinder lid 14. At the end of the expansion stroke, the exhaust valve is opened before the engine piston passes past the scavenge ports, so that the combustion gas in the combustion chamber on the piston flows out through the exhaust passage opening into the exhaust gas receiving portion 16 And the pressure in the combustion chamber is reduced. During the upward motion of the piston, the exhaust valve is closed again. Manhole covers allow repair personnel to access the exhaust gas receiving portion 16 during maintenance and disassembly.

As shown in Fig. 1, the exhaust gas receiving portion 16 is preferably supported by the scavenge receiving portion 9 of the engine main structural body 1. In alternate embodiments, the exhaust gas receiving portion 16 may be mounted to other major engine structures such as the frame box 4 or the cylinder frame 5, which may include a plurality of plate structures < RTI ID = 0.0 > (Not shown), possibly through a suitable support flange (not shown). Referring now to FIG. 1, the exhaust gas receiving portion 16 is supported on the scavenging portion 9 by a rigid main support portion 22. In the illustrated embodiment, the main support portion is provided in the middle of the exhaust gas receiving portion 16 to fix the middle of the exhaust gas receiving portion to the scavenging portion 9. Although the main support 22 is preferably centered with respect to the exhaust gas receiving portion 16, it does not necessarily have to be provided precisely in the middle and can be slightly offset. The main support portion 22 may be disposed differently at the end portion of the exhaust gas receiving portion 16. [ As shown in the figure, the exhaust gas receiving portion 16 is mounted on the scavenging accommodating portion 9 through a plurality of flexible supports 100 according to the present invention. The plurality of flexible supports 100 are distributed along the length of the exhaust gas receiver 16 on both sides of the rigid support 22. Each of the flexible supports 100 is formed by a plate structure which is adapted to receive the engine housing / scavenging receptacle 9 (or other engine structure in which it is mounted ) To the temperature of the exhaust gas receiving portion 16, as shown in Fig. During operation of the engine, the hot gases from the combustion chambers of the cylinders are accumulated in the exhaust gas receiving portion 16. Therefore, due to the thermal expansion of the material used in the exhaust gas receiving portion 16, the length of the exhaust gas receiving portion 16 will increase during engine operation. Due to the overall length of the exhaust gas receiving portion 16 in a large two-stroke diesel engine (5-20 meters), the expansion in the longitudinal direction can be significant (may be as much as a few centimeters). The overall thermal expansion of the exhaust gas receiving portion 16 in the transverse direction, i.e., the direction perpendicular to the plane of Fig. 1, is relatively small due to the small dimensions. The flexible supporting portion 100 does not exhibit or exhibit elasticity in the lateral direction of the exhaust gas receiving portion 16 so as to avoid any lateral vibration of the exhaust gas receiving portion 16. [

Conventionally, one upright plate having a thickness on the order of 10 to 25 mm has been used to make flexible supports or individual plate structures 100, and each upright plate is welded to the scavenging receptacle 9 in a conventional manner And most of the surface of the plate is oriented in the transverse direction of the exhaust gas receiving portion 16, that is, at right angles to the longitudinal axis of the elongated exhaust gas receiving portion 16, Lt; / RTI > As mentioned at the beginning, undesirable resonance vibrations of these plate structures have been experienced in the operating range of the engine.

Figure 3a shows in greater detail the end portion of the elongated exhaust gas receiving portion 16 opposite to the turbocharger 10 shown in Figure 1 and shows that the upright support plate structure 100 according to the present invention has an exhaust gas Is disposed between the receiving portion 16 and the mounting bracket 9 'of the scavenge receiving portion 9. [

The novel plate structure 100 includes mounting devices 120 and 125 each rigidly connecting the plate structure 100 to the exhaust gas receiving portion 16 and the scavenging portion 9 (as best seen in Figure 3b) And two flexible steel plates 110 and 115 extending transversely to the longitudinal axis of the exhaust gas receiving portion 16 so as to be opposed to each other. The thickness of the two plates can be the same and can be selected extensively; A plate thickness of the order of 5 to 10 mm will often be selected. In alternative embodiments, two plates of different thickness may be applied.

The plates 110 and 115 are preferably similar or identical in shape, and each plate has two opposing major surfaces and side edges. The two steel plates (110, 115) are arranged such that the major surface of each plate is opposite the major surface of the other plate. Each plate 110,115 has a top portion 117, a bottom portion 118 and a central region 116 as shown in Figure 3c and the plate structure 100 has a central region 116 of two plates 110,115, At least one spacer 130 that keeps the spacers 130 spaced apart from one another and spacers 130 are disposed between the two plates 110 and 115 at a location between the tops 117 and 118. The individual connectors 105,102 at the top and bottom portions maintain the two plates 110,115 closer together at the top and bottom than at the location of the spacer 130 so that the plate structure 100 is moved outwardly as shown And the two plates 110 and 115 are offset from each other in the central region 116. The spacers 130 may be positioned intermediate between the two ends 117, 118, or may be located at a location intermediate any of the two connectors 102, 105. Although the outwardly bulging structure as shown in Figure 3b and the two plates 110 and 115 fixed relative to each other by the spacer 130 provide the desired technical characteristics of the plate structure 100 as a whole, 117, 118 are not essential to the present invention.

The upper end portion 117 of the novel plate structure 100 can be mounted on the mounting flange 16 'on the exhaust gas receiving portion 16' and the lower end portion 118 can be mounted on the mounting bracket 9 ' Can be mounted to another lower mounting device 125, which is the bracket 9 'on the scavenging receiver 9 in the illustrated embodiment. Thereby, the exhaust gas receiving portion 16 is mounted on the scavenging accommodating portion 9. In alternative embodiments, the exhaust gas receiving portion 16 may be mounted to other major engine structures, such as the frame box 4 or the cylinder frame 5, through the plate structure 100 described above , Possibly through an additional support flange (not shown).

The exhaust gas receiving portion 16 is installed on the engine structure, such as the scavenging receptacle 9, through the plate structure 100 as described above, and when the engine is in the cold state, that is, The temperature of the mounting flange 16 'in the longitudinal direction of the exhaust gas receiving portion 16 at such a horizontal offset position becomes a position where the two mounting devices 120 and 125 are horizontally offset, Will be positioned closer to the support 22 that is harder than the lower mounting bracket 9 ', i.e. it will be located closer to the symmetry axis A of the hot state of the plate structure 100 as shown in Figure 3b Is offset to the right in Fig. 3B. In Fig. 4, the axis A 'of the cold phase is indicated. When the cold horizontal distance or interval between the upper mounting flange 16 'and the lower mounting bracket 9' is desirably at a high temperature operating state, the main structure of the engine, that is, Is selected to correspond to the relative longitudinal expansion of the gas receiving portion 16; In this manner, the mounting flange 16 'and mounting bracket 9' will be aligned and positioned above each other substantially without horizontal separation when the exhaust gas receiving portion 16 is at operating temperature.

The exhaust gas receiving portion 16 is installed on the engine structure such as the scavenge receiving portion 9 through the plate structure 100 as described above so that the plate structures 100 are installed before the engine operation, Is installed with the aforesaid cold state horizontal spacing between the flange 16 'and the mounting bracket 9', serves as a support for the exhaust gas receiving portion 16 as usual, and the rolling motion of the ship And serves to help secure the exhaust gas receiving portion 16 in place during the operation.

It is preferable that the plates 100 and 115 forming the plate structure 100 in the hot state be positioned symmetrically with respect to the axis A of symmetry of the hot state of the plate structure 100 as shown in FIG. Therefore, in the process of mounting the plate structure 100 in the cold state to the offset mounting flange 9 'and the mounting bracket 16', the plate structure 100 is deformed elastically or elastically in a slightly oblique or bent shape Or bent. After mechanically forcing the plate structure 100 to be aligned with the unaligned offset flange 9 'and the bracket 16', the plate structure 100 is mounted on the flange 16 'and the bracket 9' Respectively, and the plate structure 100 will take the oblique shape shown schematically in FIG. The bending force applied during mounting will be reduced to a minimum point since the exhaust gas receiving portion 16 is heated to a point where the flange 16 'and the bracket 9' are no longer horizontally offset, The main forces on the plate structure 100 in terms of forces due to the vertical loads resulting from the weight of the exhaust gas receiving portion 16 combined with the forces generated due to engine vibrations.

With respect to the connection with the plate structure 100, the bolts 106 are tightened to prevent any free rotational movement of the plate ends 117,118 relative to the mounting devices 120,125. The connectors 102 and 105 formed as metal bars can be disposed between the plates 110 and 115 at the upper and lower ends 117 and 118 and the bolts 106 are used to connect the plates 110 and 115 to each other through the connectors 101 and 105, The plate structure 100 is connected to the flange 16 'and the bracket 9' through the device 120, respectively.

In addition, bolts and nuts 133 with bolt head 132 are included in the plate structure 100 transversely and near the middle (in the region 116) between the top 117 and the bottom 118 The rows of spacers 130 that can be placed are arranged to secure the plates 110 and 115 against one another and ensure that there is no movement of the plates 110 and 115 away from each other or away from each other in the spacers 130 do. The spacers 130 are spaced apart from one another by a mutual spacing S1 (S1, S2) wider than the mutual spacings S2, S3 between the plates 110, 115 at the top portion 117 and the bottom portion 118, Holding the plates 110 and 115 in the region 116; S2 may be the same as S3. In this manner, the plate structure 100 will take the outwardly bulging geometry shown in FIG. 3B, and as a column formed as a truss structure as shown in FIG. 5 (as indicated by double arrows D in FIG. Will vibrate in the transverse direction (as indicated); It will be appreciated that such vibrations will be in the longitudinal direction of the exhaust gas receiving portion 16. The spacer 130 may be a tubular metal tube that has bolts with internal heads extending through holes formed in the plates 110 and 115 to maintain or fix the spacing S1 in cooperation with the nuts 133 . In this way, a pure mechanical connection that does not require welding can be formed.

Figure 5 shows a flash image or "snap shot" of the vibrating plate structure 100 during engine operation (not to scale). What the instantaneous image means is that the diagram momentarily shows the vibrating plate structure 100 while the plate structure is moving, i.e., vibrating. Thus, the plate structure 100 is not shown in the drawing and the two individual plates 110, 115 of the vibrating plate structure 100 can not be distinguished individually. In the drawings, the plate structure 100 is in one of the extreme positions possible. The amplitude A of the vibrations of the plate structure 100 is affected or controlled by the high stiffness of the plate structure 100 intermediate between the top 110 and the bottom 115, And the ratio of the interval S1 to the intervals S2 and S3, respectively. The amplitude A appears as the distance from the rest position to the extreme position in FIG.

Figure 6 illustrates how the lowest natural frequency of the plate structure 100 can be varied by using spacers 130 that provide the desired relative spacing S1 between the steel plates 110, 115 midway between the ends 117, For comparison purposes. The frequency values are compared for pairs of plates having different thicknesses; It will be appreciated that the lowest natural frequency increases overall as the interval S1 increases. Use of steel plates with even greater thickness will also increase the lowest natural frequency. For comparison, the vibration of a typical 16 mm single plate is shown in the figure (indicated by "diamond "). Since there is no gap in such a single plate, the reading of the vibration is located on a line parallel to the abscissa in the figure. As can be appreciated, even using a plate half the thickness of a typical thickness of 16 mm provides an advantage. Thus, material savings can be achieved through increased stiffness of the plate structure 100 compared to a conventional single plate structure.

The plate structure 100 may be formed by mechanically urging the two flat plates 110 and 115 together and then connecting the plates using connectors 102 and 105 at the ends 117 and 118 so that the exhaust gas receiving portion 16 ) And the scavenging receptacle (9), it is stressed or deflected to provide a plate structure (100) bulging outwardly. Alternatively, the two plates 110, 115 can be rolled or otherwise processed to take on an inherent, non-deflected shape, as shown in Figure 3b, and then connected to each other by bolts 106 and spacers 130 do.

Although the present invention has been described in detail for the purpose of illustration, it is to be understood that such description is for illustrative purposes only and that modifications may be effected by those skilled in the art without departing from the scope of the present invention.

The present invention also relates to a support plate structure (100) for connection between an engine main structure (1) and an exhaust gas receiving portion (16), said plate structure (100) comprising:

Two opposing steel plates (110, 115) each having a first end and a second end (117, 118);

At least one spacer 130 for maintaining the two plates 110 and 115 in spaced relation so that the plates 110 and 115 at a location 116 between the first and second ends 117 and 118, At least one spacer (130) disposed between the first and second spacers; And

The two steel plates 110 and 115 are spaced apart from each other at the ends 117 and 118 by spacings S2 and S3 as connectors 102 and 105 at the first end 117 and the second end 118, Wherein the at least one spacer (103) holds the two steel plates (110, 115) at spacers (130) with a greater spacing (S1) between them, do. The support plate structure 100 may include any of the features described in claims 1 to 10.

The invention relates to a vessel comprising a large two-stroke diesel engine with a support plate structure (100) having the features of any of the claims 1-10.

The term " comprising "in the claims does not exclude other elements or steps. The articles or articles specified in the claims do not exclude a plurality. A single processor or other unit may perform the functions of any of the means described in the claims.

1. Engine main structure 2. Bed plate
3. Fly Wheel 4. Frame Box
5. Cylinder frame 6. Cylinder liner

Claims (10)

Engine main structure (1);
An elongated exhaust gas receiving portion (16) having at least one engine exhaust gas inlet and at least one engine exhaust gas outlet;
A main support portion 22 and a plurality of upright plate structures 100 disposed below the exhaust gas receiving portion 16 to support the exhaust gas receiving portion 16 on the engine main structural body 1 As a large two-stroke diesel engine,
The upright plate structure 100 is distributed along the length of the exhaust gas receiving portion 16,
Each of the upright plate structures 100 has an upper end portion 117 mounted on the exhaust gas receiving portion 16 and a lower end portion 118 mounted on the engine main structural body 1,
At least one of the plate structures 100 comprises:
And the steel plates are fixed together at the upper end portion 117 and the lower end portion 118 and are arranged to extend transversely in the longitudinal direction of the exhaust gas receiving portion 16 ,
The steel plates 110 and 115 extend their major surfaces facing each other and the spacing between the steel plates is increased from the top portion 117 and the bottom portion 118,
At least one spacer 130 is disposed between the steel plates 110 and 115 at a location between the upper end 117 and the lower end 118,
The at least one spacer (130) is adapted to secure the spacing (S1) between the steel plates (110, 115) at the spacer (130). The method according to claim 1,
The at least one spacer 130 is arranged to provide the greatest spacing S1 between the plates 110 and 115 midway between the top portion 117 and the bottom portion 118. The large two- . 4. The method according to any one of claims 1 to 3,
The plate structure 100 is flexible in the longitudinal direction of the exhaust gas receiving portion 16 so as to accommodate the thermal expansion of the exhaust gas receiving portion 16 with respect to the engine main structural body 1, . 3. The method according to claim 1 or 2,
Mounting devices 120 and 125 for rigidly mounting the plate structure 100 to the exhaust gas receiving portion 16 at the upper end portion 117 and firmly mounting the plate structure 100 at the lower end portion 118 to the engine main structural body 1, Gt; 2-stroke < / RTI > diesel engine. 3. The method according to claim 1 or 2,
Wherein the steel plates (110, 115) of the at least one plate structure (100) are deflected away from each other by the at least one spacer (130). 3. The method according to claim 1 or 2,
The at least one spacer (130) provides a mechanical connection between the steel plates (110, 115). 3. The method according to claim 1 or 2,
Wherein the at least one spacer (130) forms the spacing (S1) between the steel plates (110, 115) at the spacer (130) by its length. 3. The method according to claim 1 or 2,
The at least one spacer (130) establishes a mechanically fixed spacing (S1) between the steel plates (110, 115) at the spacers (130) without any welding. 3. The method according to claim 1 or 2,
Wherein the plate structure (100) is supported by a scavenging receptacle (9) of the engine main structure (1). 3. The method according to claim 1 or 2,
Wherein the plurality of spacers (130) are arranged in rows.

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