EP2895712A2

EP2895712A2 - Method and apparatus for collecting samples of oil from marine engines

Info

Publication number: EP2895712A2
Application number: EP13739248.6A
Authority: EP
Inventors: Fabian CHEW
Original assignee: Flame Marine Ltd
Current assignee: Flame Marine Ltd
Priority date: 2012-07-27
Filing date: 2013-07-09
Publication date: 2015-07-22
Also published as: KR20150040968A; WO2014016559A2; GB2505760B; GB201312414D0; GB201213385D0; JP2015525850A; WO2014016559A3; GB2505760A

Abstract

A device for collecting oil from a marine engine comprising a helical collection conduit (12) connected to receive a mixture of oil and scavenge gas (i.e. air) from the marine engine. The curvature of the helical conduit and the flow speed distribution in the tube combine to cause the oil to accumulate on the inner surface of the conduit, from where is drains under gravity into a collection container (30).

Description

METHOD AND APPARATUS FOR COLLECTING

SAMPLES OF OIL FROM MARINE ENGINES

FIELD OF THE INVENTION

The invention relates to devices for collecting oil from marine engines.

BACKGROUND TO THE INVENTION

It is known to monitor the running behaviour of a two stroke marine diesel engine by analysing a sample of the cylinder drain oil. The contents of the oil can provide information about combustion quality, adequacy of lubrication and wear condition. For example, the wearing of engine parts produces minute particles which are picked up by the drain oil. Detection of these particles gives information about the parts that are wearing and the extent to which it is wearing. Monitoring the oil contents also provides information on the adequacy of lubrication applied. This allows the cylinder oil feed rate into the engine to be adjusted in a safe and cost effective manner. Over-lubrication can cause piston deposits which disturb the free movement of the piston rings and cause misalignment leading to increase engine wear as well as increasing the generation of particulates which cause air pollution .

To analyse the oil, it must be extracted from the under- piston drain of an engine. Fig. 1 is a schematic drawings conventional cylinder drain oil sampling point in a marine engine. The marine engine 50 has a cylinder oil drain pipe 52 extending from the under-piston space of the engine. A shut off valve 56 is mounted on the drain pipe 52 to enable it to be closed. A sampling line 54 is connected upstream of the shut off valve 56. The sampling line 54 has a sampling valve 58 mounted on it. Samples are collected by closing the shut- off valve 56 and opening the sampling valve 58 to collect the drain oil into a suitable container.

However, the under-piston space from which the used cylinder oil drains is pressurised by the intake air. This air, called "scavenge air", flows out with the used cylinder drain oil and causes a spray as the oil is being collected. This spraying makes collection of the sample difficult; it may create a mess and may constitute a health hazard.

The conventional collection technique also encounters problems in more recent engine designs, where a low cylinder oil feed rate is applied, which reduces the amount of cylinder drain oil that flows towards the drain when the shut off valve is closed. The result is a long waiting time before sufficient cylinder drain oil sample can be collected and collected samples which may not be representative.

SUMMARY OF THE INVENTION

At its most general, the invention proposes drain pipe configuration and a collection device for an engine which:

- allows a contemporaneous flow of the scavenge air and oil out through a drain line, which assists in transporting the oil out of the drain, and

- causes droplets and mist of oil to combine and separate from the scavenge air for collection.

According to the invention there may be provided a device for collecting oil from a marine engine, the device having a sampling port attachable to receive a mixture of oil and scavenge gas (i.e. air) from the engine, a curved collection conduit arranged to receive oil and gas from the sampling port at a first end and to output collected oil at a second end, wherein the curved collection conduit is helical.

The marine engine may be a two stroke diesel marine engine . The device may be used to collect oil from any oil and air mixture output from the engine. For example, the device may be used to collect cylinder drain oil, e.g. from the under-piston space of a marine diesel engine.

In use, the device receives the mixture of oil and gas into the helical collection conduit. As the mixture flows through the conduit, two phenomena occur:

- the curvature of the helical conduit and centrifugal force cause the oil to impact onto the internal surface of the conduit, and

- according to lamina flow theory in a tube, the flow speed of the mixture decreases from a maximum at the centre of the conduit towards the internal surface. This variation in flow speed causes the oil that impacts onto the inner surface of the conduit to accumulate. This theory applies to the invention, as the scavenge air is ejected under pressure from within the engine.

The collection conduit is arranged to separate the oil from the air. The dimensions of the conduit are selected to ensure that, when the oil and air emerge from the second end thereof, they will be almost completely separated.

The second end of the collection conduit may be located in a bottom chamber that is arranged to allow the separated air to escape freely while capturing the separated oil. The device may comprise a funnel (e.g. a conical or tapering flow channel) for channelling oil collecting at the second end of the conduit to a suitable receptacle (sampling container) . The second end of the conduit may be located in the top of the funnel. The funnel may be in or part of the bottom chamber. The separated oil may flow through the funnel under gravity. Before separation, the flow of oil may be facilitated by the flow of scavenge air.

The sampling port may be attachable to a drain line from the under-piston space. The device may comprise a sampling valve to open and close the conduit. The sampling valve may be a full flow ball valve, which allows unrestricted flow when open so that the drain oil will be pushed into the drain line by the air flow. The sampling valve may be in the sampling port or at any point in the conduit. Alternatively, the sampling valve may be in the drain line of the engine, i.e. already present as a shut off valve for the engine itself.

The device may comprises a support, e.g. a retaining frame, for holding the conduit in position during use. The support may be a cylindrical frame securely mounted on a surface (e.g. the floor) of the engine room. As the oil and air are travelling through the conduit under pressure, the support holds the conduit steady to prevent spillage. The support may have a first positioning member, e.g. an internal ledge, for receiving the base of the helical conduit. The support may have a second positioning member, e.g. internal flange, for mounting over the top of the helical conduit. The first and second positioning members may thus form a bracket for holding the conduit. The positioning members may be shelves which project inwards from the side walls of the cylindrical frame.

The drain line may be a pre-existing oil drain pipe of the engine. Alternatively, the drain line may be provided (e.g. retrofitted) to an engine in preparation for receiving the device. For example, a new drain line may be installed in engines where the existing drain pipe has an unsuitable shape or position. The drain line may be installed by drilling a hole in the drain pipe and attaching the sampling port to this hole; or it may be via an adaptor fitted to the drain pipe. For example, the adaptor may be a collar which can be fitted to a marine engine, the collar having an opening to which the sampling port can be attached. The adaptor may have a sampling valve to control access of oil from the drain pipe to the sampling port. The device and the adaptor may both have sampling valves to prevent leaking should one fail. The sampling port may be attached to the drain pipe above the drain pipe shut off valve. This allows the shut off valve to be closed, diverting all oil from the engine to the sampling port .

Preferably, the device is upright with the first end vertically above the second end. This allows the oil to elute by gravity.

The present invention may also be expressed as a marine engine comprising the device described above, and use of the device described above for collecting oil from a marine engine.

In another aspect, the present invention provides a drain pipe configuration suited to the extraction of cylinder drain oil using the device mentioned above. According to this aspect, there is provided a drain pipe for extracting cylinder drain oil from the under-piston space of a marine diesel engine, the drain pipe comprising a run-off pipe extending laterally from the under-piston space, the run-off pipe having an outlet for extracting cylinder drain oil, wherein the runoff pipe has a cross-sectional area sized to permit free flow of scavenge air from the engine through the outlet. Herein, free flow may mean that the run-off pipe presents no obstacles to the flow of scavenge air. For example, the run-off pipe may include a smooth transition (i.e. without surface

discontinuities) into the under-piston space. The bottom surface of the run-off pipe may be level with the bottom surface of the under-piston space.

The drain pipe may include a valve for opening and closing the run-off pipe. The valve preferably does not limit the cross-sectional area of the run-off pipe. For example, the valve may be a full flow ball valve.

The outlet may be in a side surface of the run-off pipe, e.g. the outlet may comprise an sampling conduit running in a direction offset from (e.g. orthogonal to) the direction of the run-off pipe. The outlet or sampling conduit may have a smaller cross-sectional area than the run-off pipe. However, to ensure that an accurate sample is obtained, the bottom of the outlet is preferably in line with the bottom of the runoff pipe.

According to a further aspect of the invention, a method of collecting oil from a marine engine is provided, the method comprising: attaching a device having a curved collection conduit for capturing an extracted sample of oil to a marine engine and collecting an oil sample from the conduit. The device may be according to the first aspect of the invention above .

The method may comprise flushing the conduit with compressed air before collecting the oil sample. In this way an earlier sample can be prevented from contaminating the next sample .

Preferably the device is attached to the drain pipe of the engine. In which case, the method may further comprise closing the shut off valve of the engine's drain pipe so as to direct all oil from the engine to the device.

The method may also comprise analysis of the oil according to known techniques. For example, the content of the oil may be assessed using any one or more of inductively coupled plasma mass spectrometry (ICP-MS) , X-ray fluorescence (XRF) and physical tests for viscosity, dispersancy, Total Base Number (TBN) , water content, and sooty insoluble

material .

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention are described below with reference to the accompanying drawings, in which:

Fig. 1 is a schematic drawing of a cylinder drain oil sampling point in a marine engine as known in the art, and is discussed above;

Fig. 2 is a schematic cross-sectional view of a

collection device that is an embodiment of the invention; Fig. 3 is a schematic drawing illustrating the collection device of Fig. 2 attached to a marine engine;

Fig. 4 is a flow diagram of a method of collecting oil from a marine engine that is an embodiment of the invention;

Fig. 5 is a schematic drawing illustrating the collection device of Fig. 2 attached to an alternative drainage

configuration for a marine engine;

Figs. 6A and 6B are cross-sectional views through a cylinder oil drain pipe; and

Fig. 7 is a schematic cross-sectional view of a

collection device that is another embodiment of the invention.

DETAILED DESCRIPTION; FURTHER OPTIONS AND PREFERENCES Fig. 2 shows a cross-sectional view of a device 10 that is an embodiment of the invention. A coiled length of tubing (conduit) 12 is supported in a cylindrical housing 14. At a first end 16, the tubing is connected to a sampling port 15 which is attachable to a marine engine. The second end 18 of the tubing leads into a funnel 20 connected to the housing 14.

The tubing 12 is supported within the housing by a lower shelf 22 which along with the upper shelf 24 brackets the tubing in the housing. The shelves 22, 24 serve to retain the tubing in the housing 14 during the collection of oil. The second end of the tubing 18 sits below the lower shelf 22, projecting into the funnel 20. A stand 26 supports the housing and places the outlet of the funnel above a collecting point 28 where a container 30 to collect the oil is placed.

The housing 14 is open at its top end to permit the air travelling through the device to escape. The coiled tubing is arranged so that the first end 16 is higher than the second end 18, whereby oil depositing on the inner surface of the tubing flows under gravity into the funnel 20.

The coiled tubing may be a helical conduit having about ten coils. The number of coils may be selected to strike a balance between effective separation of oil from the air in which it is entrained and speed of collection. In the embodiment, a 15 mm ^χ 22 mm hose is used for the coiled tubing. This size of tubing is practical in terms of flow cross section and overall size of the device, but other sizes may be used.

Fig. 3 shows attachment of the device of Fig. 2 to a marine engine 40. The cylinder oil drainage configuration in Fig. 3 is similar to Fig. 1. The marine engine 40 has a cylinder oil drain pipe 42 extending from the under-piston space of the engine. A shut off valve 44 is mounted on the drain pipe 42 to enable it to be closed. A sampling line 48 is connected upstream of the shut off valve 44. The sampling line 48 has a sampling valve 46 mounted on it. The device 10 is connected downstream of the sampling valve via a suitable conduit 49, which may be a section of flexible hose.

Fig. 4 illustrates a method of collecting oil using the device of Fig. 2. The device 10 is attached to the engine 40 via the sampling line 48 as described above. In a first step 100, a container 30 is put below the second end of the tubing

18. In a second step 102, the shut off valve 44 is closed and the sampling valve 46 in the sampling line 48 is opened to allow scavenge air in the engine drain pipe 42 to blow through the tubing 12. This removes the dirty oil from the tubing which can be collected in the container and subsequently discarded .

In a third step 104, a clean container is then put below the second end of the tubing 18 and the sampling valve 46 is opened again. The shut off valve 44 of the engine's drain pipe 42 remains closed to direct all oil from the engine through the sampling valve 46 and into the device.

In a fourth step 106, after the sample valves are open, further scavenge air and oil blow out of the second end 18 of the device. The scavenge air passes through the conduit and out of the device, venting out at the top of the device. The oil follows, for example, under gravity as shown here where the device is upright with the first end 16 vertically above the second end 18, causing accumulated oil to drain down to the sampling container 30 below. Oil is collected in the sampling container until a sufficient amount is drawn for analyses, for example, approximately 100 ml.

In a fifth step, after sufficient oil is collected, the shut off valve 44 is opened again, the sampling valve 46 is closed and the sample is thoroughly mixed and poured into a sampling bottle for analysis.

Fig. 5 shows an alternative drainage configuration that may be suitable for use with the collection device of the invention. Similarly to the arrangement in Fig. 3, the marine engine 40 has a cylinder oil drain pipe 42 extending from the under-piston space of the engine. However, in this case the shut off valve 44 is mounted on a horizontal section of the cylinder oil drain pipe 42, in line with the under-piston space. The sampling line 48 is connected upstream of the shut off valve 44, which means that it too is located in line with the under-piston space of the engine. The sampling line 48 is angled away from the cylinder oil drain pipe 42, e.g. by 90°. The entrance to the sampling line 48 is an orifice 45 having a diameter smaller than the diameter of the cylinder oil drain pipe 42, but of a size suitable for permitting free flow of scavenge air from the engine through the sampling line 48.

The sampling line 48 has a sampling valve 46 mounted on it. Similarly to the arrangement shown in Fig. 3, the device 10 is connected downstream of the sampling valve via a suitable conduit 49.

The bottom of the orifice 45 is in line with the bottom of the cylinder oil drain pipe 42. This arrangement may facilitate the collection of cylinder drain oil, as

illustrated in Figs. 6A and 6B. Fig. 6A shows a cross- sectional view through the cylinder oil drain pipe 42 at the orifice 45 into the sampling line 48. The level 41 of cylinder drain oil needed in the cylinder oil drain pipe 42 for flow in the sampling line is relatively low. In contrast, Fig. 6B shows a similar cross-sectional view through the cylinder oil drain pipe 42 except that the sampling line 48 lies on the same axis as the drain pipe 42, so the orifice 45 is located midway up the side of the drain pipe 42. In this case, the cylinder drain oil needs to exceed a level 43 before a sample can be taken. The efficiency of modern engines is such that it can take a long time for cylinder drain oil to accumulate. Moreover, in some engines, the updraft in the under-piston space can blow accumulated oil away. The arrangement shown in Fig. 6A is advantageous for reducing the time required to collect a sample.

Fig. 7 shows a cross-sectional view of a oil collection device 70 that is another embodiment of the invention.

Similarly to the device shown in Fig. 2, the device 70 has a coiled length of tubing (conduit) 72 supported in a

cylindrical housing 74. The cylindrical housing 74 is supported in a stand 78. The bottom end of the housing 74 is open to allow collected oil to drain out of the tubing towards a funnel 80 mounted in the stand 78, where it is guided into a container 82.

In this embodiment, one end of the tubing 72 is connected to a sampling port (not shown) which is attachable to a marine engine. The other end 75 of the tubing terminates part way up the cylindrical housing 74 so that there is a vertical distance between it and the funnel 80. Having a vertical space here helps prevent the oil from splattering.

The cylindrical housing 74 has an inner tube 76 which with the outer wall of the housing defines an annular space containing the tubing 72. The inner tube may have a diameter of around 10 cm (4 inches) . This diameter sets the curvature for the tubing, and can reduce splattering. The inner tube 76 also functions to cover the coiled tubing in order to protect it from oil that splatters up with the exhausted air from the engine. The inner tube is easier to clean that the undulating inner surface of the coil of tubing.

When oil is collected, particular when the engine is active, it may creep up from the container 82 into the cylindrical housing 74. To prevent oil from overfilling the device, the inner tube 76 is made in two pieces with an annular ring space in between. A drain line 84 is located in the ring space. The drain line 84 has a plurality of drain holes 86 therein, through which oil creeping up the inner tube 76 passes to be carried away via drain pipe 88.

Claims

1. A device for collecting oil from a marine engine, the device having a sampling port attachable to receive a mixture of oil and scavenge gas from the engine, a curved collection conduit arranged to receive oil and gas from the sampling port at a first end and to output collected oil at a second end, wherein the curved collection conduit is helical.

2. The device of claim 1 further comprising a support for the helical conduit.

3. The device of claim 1 or 2 further comprising a funnel at the second end of the conduit for channelling collected oil to a receptacle.

4. The device of any one of the preceding claims having a drain pipe adaptor at the first end, the drain pipe adaptor being attachable to the oil drain pipe of the engine.

5. The device of claim 4, wherein the drain pipe adaptor comprises a quick-release connector.

6. A marine engine comprising the device of any one of claims 1 to 5.

7. Use of the device of any one of claims 1 to 5 to collect oil from a marine engine.

8. A drain pipe for extracting cylinder drain oil from the under-piston space of a marine diesel engine, the drain pipe comprising a run-off pipe extending laterally from the under-piston space, the run-off pipe having an outlet for extracting cylinder drain oil, wherein the run-off pipe has a cross-sectional area sized to permit free flow of scavenge air from the engine through the outlet.

9. A drain pipe according to claim 8, wherein the runoff pipe includes a smooth transition into the under-piston space .

10. A drain pipe according to claim 8 or 9, wherein the bottom surface of the run-off pipe is level with the bottom surface of the under-piston space.

11. A drain pipe according to any one of claims 8 to 10 including a valve for opening and closing the run-off pipe.

12. A drain pipe according to any one of claims 8 to 11, wherein the outlet comprise an sampling conduit extending from a side surface of the run-off pipe in a direction offset from the direction of the run-off pipe.

13. A drain pipe according to any one of claims 8 to 12, wherein the bottom of the outlet is in line with the bottom of the run-off pipe.

14. A method for collecting oil from a marine engine comprising :

attaching the device of any one of claims 1 to 5 to the engine ;

collecting an oil sample from the second end of the device .

15. The method of claim 14 further comprises cleaning the device by flushing it with scavenge air after attaching the device and before collecting the oil sample.

16. The method of claim 14 or 15 further comprising closing the shut off valve of the engine' s drain pipe so as direct all oil from the drain pipe to the device.