Oil mist detection device

Abstract

In order to provide an oil mist detection device that does not cause high costs and complies with explosion-proof specifications, an oil mist detection device (100) for detecting oil mist in a detection housing (11) includes: a sensor unit (12) housed in the housing (11) and arranged in an explosion-proof area (X) where explosion-proof measures are required; a wiring component (P) connected to the sensor unit (12); a barrier circuit (30) connected to the sensor unit (12) through the wiring component (P); and a partition component (40) through which the wiring component (P) passes. The partition component (40) is housed in the housing (11) and seals the explosion-proof area (X), and the barrier circuit (30) is arranged in a non-explosion-proof area (Y) isolated from the explosion-proof area (X) by the partition component (40).

Description

Technical Field

[0001] The present invention relates to an oil mist detection device for detecting oil mist. Background Art

[0002] As such an oil mist detection device, as shown in Patent Document 1, for example, there is an oil mist detection device that is installed in a crankcase of a marine internal combustion engine and is used to detect oil mist generated in the crankcase.

[0003] However, with recent environmental restrictions, natural gas is sometimes used as a fuel for internal combustion engines instead of heavy oil used until now. In this case, since the oil mist detection device is exposed to explosive (flammable) natural gas, explosion-proof measures are required. As a specific measure, for example, it is required to adopt an intrinsically safe explosion-proof structure in which a barrier circuit for restricting the energy supplied to a sensor unit or the like of the oil mist detection device must be provided.

[0004] However, if a device having a barrier circuit separate from the oil mist detection device is used, the manufacturing cost of the additional device will be incurred. Even if the existing oil mist device is provided with a barrier circuit, there is a possibility that the barrier circuit is exposed to natural gas, and it will not meet the requirements for explosion-proof measures.

[0005] Prior Art Documents

[0006] Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-157648 Summary of the Invention

[0007] Therefore, the main object of the present invention is to provide an oil mist detection device that does not cause high costs and meets explosion-proof specifications that have not existed until now.

[0008] That is, the oil mist detection device of the present invention is characterized in that the oil mist detection device detects oil mist in a detection housing, and the oil mist detection device includes: a sensor unit housed in the housing and disposed in an explosion-proof area where explosion-proof measures are required; a wiring component connected to the sensor unit; a barrier circuit connected to the sensor unit through the wiring component; and a partition component through which the wiring component passes, and the partition component is housed in the housing to seal the explosion-proof area, and the barrier circuit is disposed in a non-explosion-proof area isolated from the explosion-proof area by the partition component.

[0009] According to the oil mist detection device configured in this way, since the barrier circuit is disposed in the non-explosion-proof area, the barrier circuit and the sensor unit that requires explosion-proof measures can be installed in one device.

[0010] Accordingly, there is no need to manufacture a device with a barrier circuit separately from the oil mist detection device, and it is possible to provide an oil mist detection device that complies with explosion-proof specifications without incurring high costs and has not existed until now.

[0011] For example, when connecting the sensor unit and the barrier circuit using a stranded wire formed by stranding multiple wires, the gas in the crankcase passes through the gaps between the multiple wires forming the stranded wire and flows from the explosion-proof area into the non-explosion-proof area.

[0012] In order to prevent such gas from passing through, preferably, the multiple wiring components connect the sensor unit and the barrier circuit in a state where they do not contact each other.

[0013] In order to more reliably prevent the above-mentioned gas from passing through, preferably, the wiring component is a single wire.

[0014] Even when the wiring component is covered with an insulating component or the like, since the gas in the crankshaft passes through the gap between the insulating component and the wiring component, preferably, the wiring component connects the sensor unit and the barrier circuit in a manner that is not covered by the insulating component.

[0015] If there is a gap between the wiring component and the partition component, the gas in the crankshaft flows from the explosion-proof area into the non-explosion-proof area through this gap. Therefore, preferably, the wiring component penetrates the partition component airtightly.

[0016] Preferably, the partition component is an elastomer made of resin.

[0017] If so, the partition component can be closely attached to the housing, and the explosion-proof area can be reliably sealed.

[0018] As an embodiment of the barrier circuit that meets the requirements of explosion-proof countermeasures, a barrier circuit that limits the energy supplied to the sensor unit can be cited.

[0019] According to the present invention configured in this way, it is possible to provide an oil mist detection device that complies with explosion-proof specifications without incurring high costs and has not existed until now. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram showing the overall configuration of the oil mist detection device of the present embodiment.

[0021] Figure 2 It is a schematic diagram showing the internal configuration of the oil mist detection device of the present embodiment.

[0022] Figure 3 It is a circuit diagram showing the configuration of the barrier circuit of the present embodiment.

[0023] Figure 4It is a schematic diagram showing the shape of the partition member in other embodiments.

[0024] Figure 5 It is a schematic diagram showing the internal structure of the detection device in other embodiments.

[0025] Explanation of reference numerals

[0026] 100 ··· Oil mist detection device

[0027] C ··· Crankcase

[0028] 10 ··· Detection unit

[0029] 10a ··· Inlet

[0030] 10b ··· Outlet

[0031] 10c ··· Oil mist introduction chamber

[0032] 10d ··· Sensor housing chamber

[0033] 11 ··· Housing

[0034] 12 ··· Sensor unit

[0035] 13 ··· Light emitting part

[0036] 14 ··· Light receiving part

[0037] 15 ··· Substrate

[0038] W ··· Transparent window

[0039] 20 ··· Control unit

[0040] 21 ··· Computer circuit

[0041] 22 ··· Second housing

[0042] P ··· Wiring component

[0043] 30 ··· Barrier circuit

[0044] 40 ··· Partition member

[0045] X ··· Explosion-proof area

[0046] Y ··· Non-explosion-proof area Detailed implementation manners

[0047] Hereinafter, an embodiment of the oil mist detection device of the present invention will be described with reference to the accompanying drawings.

[0048] As Figure 1As shown in the figure, the oil mist detection device 100 of the present embodiment is, for example, a light scattering type device installed in the crankcase C of a marine internal combustion engine, and is used to detect the oil mist generated in the crankcase C due to overheating of bearings or the like. In addition, the use of the oil mist detection device 100 is not limited to this, and it can also be installed in internal combustion engines other than ships and used.

[0049] Specifically, the oil mist detection device 100 includes: a detection unit 10 that penetrates from the outside and is installed in an installation hole provided in the wall of the crankcase C so that the front end side protrudes into the inside of the crankcase C; and a control unit 20 that is connected to the base end of the detection unit 10.

[0050] As Figure 1 and Figure 2 shown in the figure, the detection unit 10 includes a housing 11 and a sensor unit 12 housed in the housing 11.

[0051] The housing 11 has a substantially cylindrical shape with a sealed front end face, and is formed with an oil mist inlet 10a for introducing oil mist into the interior and an oil mist outlet 10b for discharging the oil mist to the outside. A thread (not shown) for screwing connection with the installation hole of the crankcase C is formed on the outer peripheral surface of the housing 11.

[0052] As Figure 2 shown in the figure, an oil mist introduction chamber 10c configured such that oil mist can be introduced and diffused is formed on the front end side inside the housing 11, and a sensor housing chamber 10d for housing the sensor unit 12 is formed on the base end side. A light-transmitting window W such as a lens is interposed between the oil mist introduction chamber 10c and the sensor housing chamber 10d, thereby preventing the oil mist from flowing from the oil mist introduction chamber 10c into the sensor housing chamber 10d.

[0053] The sensor unit 12 detects the oil mist introduced into the oil mist introduction chamber 10c, and includes a light emitting unit 13 and a light receiving unit 14.

[0054] The light emitting unit 13 is, for example, an LED whose light emitting surface is oriented toward the light-transmitting window W. In the present embodiment, the light emitting unit 13 that emits light in a wavelength range suitable for the particle size of the oil mist is used. Of course, other light emitting units 13 such as an LD (laser diode) can also be used.

[0055] The light receiving unit 14 is, for example, a PD (photodiode) whose light receiving surface is oriented toward the light-transmitting window W, and outputs an electrical signal corresponding to the intensity of the light received by its light receiving surface. Of course, other light receiving units 14 such as a CCD can also be used, for example.

[0056] Moreover, the irradiation light emitted from the light emitting unit 13 is irradiated onto the oil mist introduced into the oil mist introduction chamber 10c through the light-transmitting window W, and the scattered light generated thereby is received by the light receiving unit 14 after passing through the light-transmitting window W.

[0057] The light emitting portions 13 and the light receiving portions 14 are arranged and disposed such that the optical axes of the irradiated light and the received light are substantially parallel to each other, and are mounted on the same substrate 15, for example. However, the optical axes of the light emitting portions 13 and the light receiving portions 14 are not necessarily parallel, and the light emitting portions 13 and the light receiving portions 14 may also be mounted on different substrates.

[0058] The substrate 15, together with the light emitting portions 13 and the light receiving portions 14, constitutes a sensor unit 12, which is housed in the sensor housing chamber 10d. One or more wiring components P are connected to the substrate 15, and the sensor unit 12 is connected to the control unit 20 through the wiring component P.

[0059] One or more wiring components P are provided. Here, a wiring component for supplying energy (current and / or voltage) from the control unit 20 to the light emitting portion 13, a wiring component for sending an electrical signal corresponding to the intensity of the scattered light received by the light receiving portion 14, that is, a detection signal, to the control unit 20, etc. are provided.

[0060] The control unit 20 structurally includes a so-called computer circuit 21 having a CPU, an internal memory, an AD converter, etc. Moreover, information processing is performed by operating according to a program stored in a specified area of the internal memory. In the present embodiment, the presence or absence of oil mist is detected based on the detection signal sent from the light receiving portion 14, and the concentration of the oil mist is measured based on the detection signal.

[0061] The control unit 20 further includes a second housing 22 that houses the above-mentioned computer circuit 21. The internal space of the second housing 22 communicates with the internal space of the housing 11 that constitutes the above-mentioned detection unit 10 to form a sensor housing chamber 10d. In addition, the second housing 22 is substantially cylindrical in shape in this embodiment, but may also be rectangular parallelepiped in shape, for example.

[0062] However, in the case of using an explosive (flammable) gas such as natural gas as fuel for a ship or the like, since the explosive gas is supplied into the crankcase C, at least the portion of the oil mist detection device 100 disposed in the crankcase C, more specifically, the portion into which the explosive gas in the crankcase C can flow, becomes an explosion-proof area X that requires explosion-proof measures.

[0063] If described in more detail, in the case of supplying an explosive gas into the crankcase C, since the explosive gas is introduced into the above-mentioned oil mist introduction chamber 10c, the oil mist introduction chamber 10c becomes an explosion-proof area X that requires explosion-proof measures. However, in the present embodiment, there are no components in the components constituting the oil mist introduction chamber 10c that require explosion-proof measures, and no specific measures for the oil mist introduction chamber 10c are required.

[0064] On the other hand, although the sensor housing chamber 10d is separated from the oil mist introduction chamber 10c by the light-transmitting window W, there is a small gap through which gas can pass between the sensor housing chamber 10d and the oil mist introduction chamber 10c. Thus, since the explosive gas flows into the sensor housing chamber 10d, this sensor housing chamber 10d is also an explosion-proof area X that requires explosion-proof measures. Moreover, a sensor unit 12 is arranged in the sensor housing chamber 10d, and components such as the light-emitting part 13, the light-receiving part 14, and the substrate 15 that constitute the sensor unit 12 may become ignition sources, so specific intrinsically safe explosion-proof measures are required.

[0065] Therefore, as Figure 2 shown, the oil mist detection device 100 of the present embodiment further includes a barrier circuit 30, and the barrier circuit 30 is connected to the sensor unit 12 through a wiring component P to limit the energy supplied to the sensor unit 12.

[0066] The barrier circuit 30 of the present embodiment and the computer circuit 21 that constitutes the above-mentioned control unit 20 are arranged on the same circuit board and housed in the second housing 22. However, as the barrier circuit 30, it may also be arranged on a circuit board separate from the computer circuit 21.

[0067] This barrier circuit 30 is a circuit for ensuring the intrinsically safe explosion-proof structure of the oil mist detection device 100, and has a function of limiting the energy supplied to the sensor unit 12 so that various electronic components that constitute the sensor unit 12 do not become ignition sources. Specifically, as Figure 3 shown, this barrier circuit 30 at least has: a current limiting element 31 that limits the current flowing into the sensor unit 12 to a specified current value or less; and a voltage limiting element 32 that limits the voltage applied to the sensor unit 12 to a specified voltage value or less, and here also has a protection element 33 that protects the voltage limiting element 32.

[0068] Then, as Figure 2 shown, the oil mist detection device 100 of the present embodiment further includes a partition member 40, and the partition member 40 is housed in the above-mentioned housing 11 to seal the explosion-proof area X, and the barrier circuit 30 is arranged in a non-explosion-proof area Y isolated from the explosion-proof area X by the partition member 40.

[0069] If described in more detail, the above-mentioned wiring component P penetrates the partition member 40, and the partition member 40 hermetically seals the oil mist introduction chamber 10c and the sensor housing chamber 10d that are the explosion-proof area X. Specifically, the partition member 40 is a substantially cylindrical member arranged in the housing 11 in such a way that the entire outer peripheral surface is in airtight contact with the inner peripheral surface of the housing 11.

[0070] In addition, the partition member 40 here is, for example, a resinous elastomer such as a liquid gasket that becomes silicone rubber when cured, and its outer diameter is in close contact with the inner wall of the housing 11. However, the material of the partition member 40 is not limited to this, and as long as it is a material through which gas does not pass, it can also be appropriately changed to glass, ceramics, etc.

[0071] Through this partition member 40, the inside of the device (inside the housing 11 and the second housing 22) is divided into an explosion-proof area X on the front end side relative to the partition member 40 and a non-explosion-proof area Y on the base end side relative to the partition member 40. In this embodiment, the explosion-proof area X is an area arranged inside the crankcase C, and the non-explosion-proof area Y is an area arranged outside the crankcase C. Moreover, gas cannot flow between these explosion-proof area X and non-explosion-proof area Y, and the above-described barrier circuit 30 is arranged in this non-explosion-proof area Y.

[0072] The oil mist detection device 100 of this embodiment is configured to also prevent gas from flowing from the explosion-proof area X into the non-explosion-proof area Y due to the wiring member P.

[0073] Specifically, if it is assumed that the wiring member P is, for example, a stranded wire formed by stranding multiple wires (wirings), the gas inside the crankcase C passes through the gaps between the multiple wires (wirings) that make up the stranded wire and flows from the explosion-proof area X into the non-explosion-proof area Y.

[0074] Therefore, in this embodiment, the multiple wiring members P connect the sensor unit 12 and the barrier circuit 30 in a state where they do not contact each other, that is, in a state where they are non-contact with each other.

[0075] More specifically, these wiring members P are linear or pin-shaped metals called single wires or single pins, and are used in a state where they are not covered by a covering member such as an insulating member and their surfaces are exposed.

[0076] The entire circumference of the outer peripheral surface of these wiring members P is in airtight contact with the inner peripheral surface of the through hole formed in the partition member 40, whereby the wiring members P airtightly penetrate the partition member 40 in a state where there is no gap through which gas can pass.

[0077] According to the oil mist detection device 100 configured in this way, since the barrier circuit 30 is arranged in the non-explosion-proof area Y, the barrier circuit 30 and the sensor unit 12 that require explosion-proof measures can be installed in one device.

[0078] Thereby, it is not necessary to manufacture a device having the barrier circuit 30 separately from the oil mist detection device 100, and an oil mist detection device 100 that does not cause high costs and complies with explosion-proof specifications can be provided.

[0079] In addition, as the plurality of wiring components P, since twisted wires are not used and single wires or single pins that do not contact each other are used, it is possible to prevent the passage of gas generated when twisted wires are used. Moreover, since the wiring component P penetrates the partition member 40 airtightly without being covered by a covering member, it is possible to reliably prevent gas from flowing from the explosion-proof area X into the non-explosion-proof area Y.

[0080] Furthermore, the partition member 40 is an elastic body made of resin and has good adhesiveness, so it is possible to reliably seal the explosion-proof area X.

[0081] In addition, the present invention is not limited to the above-described embodiments.

[0082] For example, in the above-described embodiments, the partition member 40 is a cylindrical member. However, as Figure 4 shown, the partition member 40 may also be a concave member or a convex member. In short, as long as the entire circumference of the outer peripheral surface of the partition member 40 is in airtight contact with the inner peripheral surface of the housing 11, the shape of the partition member 40 can be changed into various shapes.

[0083] In addition, as Figure 5 shown in the upper figure in, a part of the explosion-proof area X may also extend to the outside of the crankcase C. As Figure 5 shown in the lower figure in, a part of the non-explosion-proof area Y may also extend to the inside of the crankcase C.

[0084] In addition, the present invention is not limited to the above-described embodiments, and various modifications can of course be made without departing from the gist of the present invention.

[0085] Industrial Applicability

[0086] According to the present invention, it is possible to provide an oil mist detection device that meets explosion-proof specifications and does not cause high costs and has not existed so far.

Claims

1. An oil mist detection device, characterized in that, The oil mist detection device detects the oil mist inside the detection housing. The oil mist detection device includes: A sensor unit, housed inside the housing and disposed in an explosion-proof area that requires explosion-proof measures, for detecting the oil mist introduced into the housing; A wiring component, connected to the sensor unit; A partition component, through which the wiring component penetrates, and the partition component is housed inside the housing, dividing the inside of the oil mist detection device into the explosion-proof area and the non-explosion-proof area, and sealing the explosion-proof area in such a way that gas cannot flow between the explosion-proof area and the non-explosion-proof area; And A barrier circuit, disposed in the non-explosion-proof area, connected to the sensor unit through the wiring component, and restricting the energy supplied to the sensor unit.

2. The oil mist detection device according to claim 1, characterized in that, Multiple of the wiring components connect the sensor unit and the barrier circuit in a non-contact state with each other.

3. The oil mist detection device according to claim 1 or 2, characterized in that, The wiring component is a single wire.

4. The oil mist detection device according to claim 1 or 2, characterized in that, The wiring component connects the sensor unit and the barrier circuit in a manner not covered by an insulating component.

5. The oil mist detection device according to claim 1 or 2, characterized in that, The wiring component penetrates the partition component airtightly.

6. The oil mist detection device according to claim 1 or 2, characterized in that, The partition component is an elastomer made of resin.

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