WO1999015853A1

WO1999015853A1 - Device for determining the internal measurements of cylinder linings

Info

Publication number: WO1999015853A1
Application number: PCT/SE1998/001704
Authority: WO
Inventors: Hans Sundén
Original assignee: DAROS HOLDING AB
Current assignee: DAROS HOLDING AB
Priority date: 1997-09-25
Filing date: 1998-09-24
Publication date: 1999-04-01
Anticipated expiration: 2000-03-25
Also published as: AU9290298A; SE9703459L; SE510793C2; EP0941449A1; KR20000069093A; SE9703459D0

Abstract

The invention concerns a device for determining the internal measurements of a cylinder lining (6). Primarily large-size cylinder linings (6) are concerned, such as those used in marine engines. The device comprises a suspension unit (4) which is arranged to be placed above an essentially vertically upright cylinder lining (6). The device further comprises a measuring unit (5) which is arranged to be lowered from the suspension unit (4) into the cylinder lining (6) and which is provided with means (28, 34, 36) for performing a series of measuring operations and determining distances from a line of reference (11) extending between the suspension unit (4) and the measuring unit (5) to the inner wall (26) of the cylinder lining (6) at a plurality of levels and in several different radial directions at each level.

Description

DEVICE FOR DETERMINING THE INTERNAL MEASUREMENTS OF

CYLINDER LININGS

The present invention concerns a device for determining the internal measurements of cylinder linings, especially large-size cylinder linings used in marine engines. In order to optimise the operational conditions of marine engines and to prevent shut-downs to the largest extent possible, the operational state of the engines is checked at regular intervals. One common cause for impaired engine state or for shut-downs is that the piston rings have become worn-out or burnt and conseguently need to be replaced. Experience has shown, however, that the cause may equally well be the cylinder-mounted linings which, when examined, have been found to be in a worn state or to no longer ex- hibit a smooth surface because of depositions of soot or of corrosive attacks on the lining walls. Attacks of this kind might be due to sulphurous fuel used to operate the engine, which in combination with steam produces sulphuric acid that condenses at predeter- mined temperature and pressure levels in the engine.

The effects on the cylinder from the corrosion attacks are localised because of the uneven distribution of cylinder oil, of gas leakage via openings, such as passages between piston rings and linings, and/or variations of the cylinder wall temperature.

Cylinder lining checks have hitherto been made entirely manually. The preliminary work, preceding the measuring operation as such, is comparatively extensive. Initially, the cylinder head of the engine must be dismantled and the piston of one cylinder be lifted out before an operator may enter the cylinder, using a ladder which is lowered into the cylinder. In addition, a ruler having pre-punched holes therein is inserted vertically into the cylinder alongside the inner wall of the cylinder lining. With the aid of a measuring rod, a number of different diameter measurements, usually about ten, are taken vertically in the fore-and-aft as well as in the thwartships directions.

In this manner it is possible to make an as a rule incomplete evaluation of the state of the cylinder lining as concerns the amount of soot deposition and the number of corrosion damages and their size. However, this method is completely insufficient when one wishes to determine any deviations in the cylinder lining from the cylindrical shape, i.e. to determine whether the heat stress to which the cylinder lining has been exposed has caused the lining to deform, resulting in the lining adopting an S-like configuration or a somewhat banana-curved configuration. The present invention provides a device with the aid of which it becomes possible, after dismantling of only a few engine components, to rapidly and comparatively conveniently perform a large series of measuring operations in an arbitrary number of radial directions at a selected level calculated from the centre of a cylinder lining to its internal wall, and at an arbitrary number of levels in the cylinder lining. The characteristic features of the device are defined in the appended claims. Several possible embodiments of the invention will be described in more detail in the following with reference to the accompanying drawings, wherein

Fig. 1 is a broken view of a cylinder equipped with the device in accordance with the invention, which device consists of a suspension unit resting on top of the cylinder, and of a measuring device lowered into the cylinder, Fig. 2 is a perspective exploded view of components forming part of the suspension unit,

Fig. 3 is also a perspective exploded view of components forming part of the measuring device, and Figs 4 and 5 are views of alternative embodiments of the measuring unit.

Fig. 1 illustrates a cylinder 1 having a piston 2 and a head 3 from which an exhaust valve has been removed to accommodate the measuring device in accord- ance with the invention. The latter consists of a suspension unit 4 which is arranged to rest on the cylinder head 3, and of a measuring unit 5 which is arranged to be lowered into the cylinder 1. In the cylinder 1 is mounted a lining 6 the measurements of which are to be determined.

The suspension unit 4 is connected to the measuring unit 5 by means or wires or, as shown in the drawing, by means of straps 7. Each strap 7 may be reeled onto or unreeled from a roller 8 which is actuated by a motor 9. Controls, not shown in the drawing, are provided to actuate each individual motor 9, ensuring complete control at all times of the length of unreeled strap and consequently knowledge of the level occupied by the measuring unit 5. The suspension device 4 is provided with a laser directing means 10 which is arranged to direct a beam of light 11 downwards, onto a position sensitive detector 12 (PSD) located in the measuring unit 5. Preferably, the laser directing means 10 is devised in the manner more clearly apparent from Fig. 2. A translation-motion table consists of two plates 13, 14 each having a setting nut 15 and 16, respectively, for displacement of the plates in mutually perpendicular directions. Each plate 13, 14 is formed with an oval aperture 17 and 18, respectively, extending at right angles to one another. The laser directing means 10 is mounted in a bushing 19, the latter in turn mounted in the two oval apertures 17, 18. In addition, the laser directing means 10 is formed with a domed portion 20 the purpose of which is to engage in a protrusion 21 formed in the bushing 19. With the aid of the components associated with the translation-motion table it is possible to displace the laser directing means 10 laterally in two mutually perpendicular directions and in addition thereto to adjust the inclination of the table in such a manner that the beam of light 11, intended to form a line of reference when setting the measuring unit 5 in position, impacts on the PSD 12 as close to the centre thereof as possible.

According to the embodiment illustrated in Figs 1 and 3, the measuring unit 5 includes an upper ring 22. From said ring extend radially outwardly three adjusting means 23 and from said means project in turn three support legs 24 each one of which supports at its outer free end a small wheel 25 which may be set in position of abutment against the inner wall 26 of the cylinder lining 6 when actuated by the respective adjusting means 23. The adjusting means 23 may consist of linearly acting means actuated by an integrated motor of known design and are used to centre the measuring unit 5 in the cylinder lining 6, preparatory to the start of the measuring operation.

Once the measuring unit 5 has been lowered to the desired level and the small wheels 25 have been moved into their position of abutment against the inner wall 26, the upper ring 22 is non-rotationally clamped to the cylinder lining 6.

The measuring unit 5 likewise comprises a lower ring 27 through which passes a measuring rod 28. The lower ring 27 is integrally connected to an actuating ring 29, the latter in turn being connected to the upper ring 22 by way of a bearing 30. The actuating ring 29, and thus the lower ring 27 and the measuring rod 28, are mounted for rotation over 360° in both directions when actuated by a step motor 31, the latter being connected to the actuating ring 29 via a cogged belt 32, as shown in Fig. 3, or in some other way. The measuring rod 28 is supported in the lower ring 27, for instance by means of ball bushings, not shown, and it is displaceable radially into a position in abutment against the inner wall 26 of the cylinder lining 6, by means of a solenoid 33. The PSD 12 is mounted on the measuring rod 28, in the centre of the measuring unit 5.

Fig. 4 illustrates an alternative embodiment of the measuring unit 5. In accordance with this alternative embodiment, the measuring unit 5', instead of being formed with the measuring rod 28, comprises an essentially horizontally disposed laser directing means 34. The PSD 12 is disposed on the upper face of the laser means in order to orientate the measuring unit 5' in manner similar to that earlier described, with the aid of the beam of light 11. The laser directing means 34 is arranged to direct a second beam of light 35 against the inner wall 26 of the cylinder lining 6. The laser directing means 34 is arranged to be turned over 360° to determine an optional number of radial measurements.

Fig. 5 illustrates a further alternative embodiment of the measuring unit. In this case the measuring unit 5" is provided with a vertically disposed laser directing means 36 which directs a beam of light 37 against a rotary, obliquely positioned mirror 38 which deflects the beams of light at right angles outwardly, against the inner wall 26 of the cylinder lining 6. By turning the mirror 38 it is thus possible to determine radial measurements in different angular directions. The PSD 12 arranged to orientate the measuring unit 5" in the centre of the cylinder lining 6 is in this case positioned on the upper end wall of the laser directing means 36.

The device in accordance with the invention likewise comprises a separate computer unit, not shown in the drawings, into which may be entered a program designed for measuring a cylinder lining 6. The suspension unit 4 and the measuring unit 5 comprise one software module (processor) each, not either shown, which are connected to the computer unit. The measure- ments to be registered are, in additional to the radial measurements, also the temperature of the cylinder lining 6 at each measurement point as well as the time and the date of the measuring operation.

Before start of a measuring operation, the posi- tion of the laser directing means 10 is checked, and if required, it is adjusted to ensure that its beam of light 11, serving as a line of reference, coincides to the highest possible extent with the longitudinal axis of the cylinder lining 6. The measuring unit 5 is thereafter lowered to a lowermost position and its centred and inclined attitude interiorly of the cylinder lining 6 is measured and corrected, whereupon the upper ring 22 is fixed in position.

A pre-programmed measuring sequence may now be started during which the measuring unit 5 performs a series of radial measuring operations with the lower ring 27, or the laser directing means 34, or the mirror 38, set in different angular positions. The measurement values thus obtained are stored in the pro- cessor memory of the measuring unit 5 and are then transferred either to the processor memory of the suspension unit 4 or directly to the computer unit. Following release of the measuring unit 5, raising it one step and immobilising it at the upper level, the measuring sequence just described is repeated. Once a complete measuring procedure has been performed and all measurement values are stored in the processor memory of the suspension unit 4 the measurement data may be transferred to the computer unit for presentation and analysis.

The measurement values could be presented on the screen of the computer unit on which the collected radial measurements are shown in the form of a diagram of contour lines with numerical data added, similar to a topographic map. The presentation could also be in the form of a pattern of colours wherein the depths or heights represented by each colour are also indicated. The device in accordance with the invention is very convenient and practical to handle. As mentioned above, the measuring unit 5 is secured in position by means of the adjusting means 23 preliminary to the start of a measuring sequence. By measuring the position of the beam of light 11 in the X and Y coordinate directions on the PSD 12, see Fig. 1, it becomes possible to calculate a normalised radial measurement which is stored in the processor of the suspension unit 4. The beam of light 11 then serves as a reference line by means of which it becomes possible to determine, during the measuring sequence, not only the radial measurements but also whether the cylinder lining 6 is bent (into a banana shape) or deviates from the true cylindrical shape in some other way.

In order to further simplify and accelerate the evaluation of the measuring sequence one may chose to show only those parts of the interior wall 26 of the cylinder lining 6 that present radial measurements that deviate from a predetermined limit value within a restricted area. In this manner the operator may rapidly gain information on unacceptable local wear, if any, on the cylinder lining 6.

It is an advantage if the processor of the sus- pension unit 4 is sufficiently powerful to be able to store the data from a complete measuring sequence so that consequently no exterior control is required. The reason is that in this case there is no need for bringing along a computer unit to carry out measurements in an engine room but instead the collected measurement data could be transferred to the computer unit and be presented at some other location. Rapid transfer of measurement data to the computer unit in real time is not either necessary.

The invention is not limited to the embodiments shown and described but could be varied in several ways within the scope of the appended claims. For instance, the suspension unit 4 may be equipped with a laser distance meter which directs a beam of light against a reflecting surface on the measuring unit 5. Furthermore, instead of forming the laser directing means 10 with a domed portion 20 as illustrated in

Fig. 2, the entire translation table may be disposed in a cradle.

Claims

1. A device for determining the internal measurements of cylinder linings, especially large-size cyl- inder linings used m marine engines, c h a r a c t e r i s e d in that the device comprises a suspension unit (4) which is arranged to be placed above an essentially vertically upright cylinder lining (6), and a measuring unit (5) which is arranged to be lowered from the suspension unit (4) into the cylinder lining (6) and which is provided with means (28, 34, 36) for performing a series of measuring operations and determining distances from a line of reference (11) extending between the suspension unit (4) and the measuring unit (5) to the inner wall (26) of the cylinder lining (6) at several levels and m several different radial directions at each level.

2. A device as claimed m claim 1, c h a r a c t e r i s e d in that the measuring unit (5) is sus- pended by means of wires or straps (7) which are arranged to be reeled on or off rollers (8) supported by the suspension unit (4), m order to adjust the vertical setting of the measuring unit (5) .

3. A device as claimed m any one of the preced- mg claims, c h a r a c t e r i s e d m that the suspension unit (4) is provided with a first laser directing means (10) arranged to direct a beam of light (11) against a position-sensitive detector (12) located in the vicinity of the measuring unit (5), said beam of light (11) forming said line of refer^¬ ence .

4. A device as claimed m any one of the preceding claims, c h a r a c t e r i s e d in that the first laser directing means (10) is located m a translation-motion table (13, 14) m which said laser directing means (10) is movable essentially perpendicularly to the direction of the beam of light (11) in two mutually perpendicular directions, said translation-motion table consisting of one bottom plate (14) formed with an oval hole (18) therein, and one upper plate (13) likewise formed with an oval hole (17) therein, which latter hole extends at right angles to the first-mentioned hole (18) in a plane above and in parallel with the plane in which is positioned said first-mentioned hole (18), and in that the laser directing means (10) extends through both said holes (17, 18) .

5. A device as claimed in claim 4, c h a r a c t e r i s e d in that the first laser directing means

(10) is provided with a peripherally extending domed portion (20) which is received in a complementary pro- trusion (21) formed in a bushing (19) which is mounted in the holes (17, 18), in order to allow setting of the laser directing means (10) in different positions of inclination.

6. A device as claimed in claim 1, c h a r a c - t e r i s e d in that the measuring unit (5) is provided with at least three support legs (24) which project radially from the measuring unit (5), each in a different direction, and are arranged to be extended by means of their respective adjusting means (23) into contact with the inner wall (26) of the cylinder lining (86), for the purpose of anchoring the measuring unit (5) at a selected level in the cylinder lining ( 6) .

7. A device as claimed in claims 1 and 6, c h a r a c t e r i s e d in that the measuring unit (5) is provided with a part (27) which is mounted for rotary movement relative to the support legs (24) and in that said part (27) is provided with the means (28, 34, 36) arranged to measure the distance to the inner wall (26) of the cylinder lining (6).

8. A device as claimed in claims 3 and 7, c h a r a c t e r i s e d in that said means consist of a second laser directing means (34) which is rota- tionally mounted relative to the support legs (24) and which is provided on its upper face with a position sensitive detector (12) arranged to capture the reference-line forming beam of light (11) that is emitted from the first laser directing means (10) and to determine the position of the second laser directing means (34), and in that said second laser direct- ing means (34) is arranged to emit a second beam of light (35) essentially at right angles to the first beam of light (11) in the direction towards a selected point on the inner wall (26) of the cylinder lining (6) in order to determine the distance from the beam of light (11) that forms the line of reference to said point on the inner wall (26) .

9. A device as claimed in claim 8, c h a r a c t e r i s e d in that the second laser directing means (36) is stationary relative to the support legs (24) and emits a downswards directed beam of light

(37), and in that a rotary mirror (38) is arranged to capture said beam of light (37) and to direct said beam towards the inner wall (26) of the cylinder lining (6) essentially at right angles to the beam of light (11) that forms the line of reference.

10. A device as claimed in claim 7, c h a r a c t e r i s e d in that the rotary part (27) may be set in different angular position by means of a step motor (31), and in that it comprises a measuring rod (28) which is equipped with a position sensitive detector (12), said detector being located in the optical path of the beam of light (11) that forms the line of reference and being arranged to determine the position of the measuring rod (28), the latter being displace- able lengthwise into contact with the inner wall (26) of the cylinder lining (6) to determine the distance from the beam of light (11) that forms the reference line to the point of contact in question on the inner wall (26) .