OPTICAL DETECTOR DEVICE

Description

[0001] The invention relates to an optical detector device comprising a housing with a projecting nozzle which is closed off to the outside by a light-transmitting disc, under which at least one optical fiber tapering towards an optical sensor is arranged.

[0002] Such a device for detecting sparks, fires, and embers within a material flow is known from DE 20 2013 006 142 U1. In the embodiment shown therein, a cylindrical sheath of a suitably coated optical fiber is received in the nozzle of the housing, and this optical fiber tapers towards an optical sensor to a cross-section that corresponds to the active area of ​​the sensor, a photosensitive element.

[0003] A problematic aspect of this device has been the monitoring of the entire spectrum, which here encompasses the entire range from infrared to ultraviolet, with only one sensor. Against this background, the invention aims to provide an optical detector device that enables highly precise measurement of the entire spectrum.

[0004] This technical problem is solved in a detector device of the generic type by the features of claim 1. Due to these features, the detector device according to the invention offers a multitude of advantages.

[0005] According to the invention, a single-piece optical fiber assembly with multiple optical fibers, e.g., two or three, is provided, so that sensors with different characteristic curves can be used. This allows for significantly improved detection of overheating and, in particular, sparks or similar phenomena within the material flow.

[0006] A preferably one-piece holding device is provided for holding and positioning the light guide arrangement with the light guides within the nozzle that penetrates the wall of a pipe limiting the material flow.

[0007] The holding device is inserted into the nozzle in a rotationally secure manner, for example by means of pre-defined grooves and springs, and is thus precisely aligned. According to the invention, a ring of the light guide assembly rests on the holding device beneath the disc, to which the light guides are radially connected on the outside.

[0008] Since the holding device is securely mounted in the nozzle and the light guide assembly is also securely and unambiguously trapped in the holding device, the light guides are positioned exactly above each sensor.

[0009] In order for the holding device to precisely enclose the light guides, according to the invention each light guide is precisely enclosed by contact surfaces of recesses of the holding device in the circumferential direction and radially inside and held against the inner wall of the nozzle over its axial length.

[0010] In the optical detector device according to the invention, it can further be provided that the ring is closed by a central light guide, preferably tapering conically towards an optical sensor.

[0011] This makes it possible to apply a signal to different optical sensors simultaneously and within a single housing, with the exact positioning of the light guides above the sensors being specified.

[0012] The design further stipulates that at least the contact surfaces of the holding device on the light guides are reflective. This largely eliminates reflections between the light guides within the nozzle.

[0013] Below the mounting device, the light guides protrude slightly, but this is hardly noticeable because a further development provides for the mounting device to have a collar that limits the insertion depth into the nozzle. This collar sits on a receptacle on a circuit board, and the receptacle has recesses in which sensors or emitters are arranged. If a sensor is arranged in each recess, the protruding light guides engage in these recesses, preventing any mutual interference.

[0014] This is not the case if the coil has tubular sheaths protruding from the underside, enclosing the light guides. In this case, only a light exit opening perpendicular to the axial extent of the nozzle remains.

[0015] In a further embodiment, the receiver can have pins protruding from its underside, which engage in recesses in the circuit board containing the evaluation electronics. This ensures that the receiver and the holder with the fiber optic assembly are aligned radially and axially with precise and predictable accuracy.

[0016] In a second variant of the detector device, the receiver has a cylinder that centrally passes through the holding device, wherein in particular the open ring and the shaft have the same inner diameters, and a sensor is held by the cylinder directly below the disc.

[0017] This is particularly useful for sensors with a large active area.

[0018] The optical properties of the material flow are passively measured using sensors. Active measurement is achieved using emitters, which can be positioned in recesses of the fixture or adjacent to it. For the emission of, for example, UV light, the fixture features a channel parallel to the nozzle's axis above the emitter. For manufacturing reasons, this channel is preferably located radially outside the fixture and has a slot facing the nozzle's inner wall.

[0019] The detector device according to the invention allows the spectrum from infrared to ultraviolet to be monitored by using multiple sensors and / or emitters.

[0020] The essence of the invention is explained in more detail with reference to the drawing, which only illustrates exemplary embodiments. The drawing shows: Fig. 1: a schematic and not-to-scale section through a detector device according to the invention, Fig. 2: a side view of a fiber optic arrangement with two fiber optics connected to a ring, Fig. 3: a top view, Fig. 4: a side view of an associated holding device, Fig. 5: a top view, Fig. 6: a side view of an associated receptacle, Fig. 7: a top view, Fig. 8: a side view of another fiber optic arrangement, Fig. 9: a top view, Fig. 10: a side view of an associated holding device, Fig. 11: a top view, Fig. 12: a top view of an associated receptacle, and Fig. 13: an isometric view.

[0021] Figure 1Figure 1 shows an idealized, not-to-scale cross-section through an optical detector device 1 according to the invention. Its housing 2 has a two-part construction. A circuit board 4 for the electronics is mounted in the lower part 3. It is connected through an opening 5 by means of an inserted plug connector or a cable harness.

[0022] The upper shell 6 is screwed to the lower shell 3 via a sealing ring 7 and has a protruding nozzle 8 that penetrates the wall of a pipe for a material flow. Towards the outside, facing the material flow, the nozzle 8 is closed in the usual manner by a translucent disc 9.

[0023] In the shaft 8, a light guide arrangement 10 is held in a rotationally secure and unambiguous manner by a retaining device 11 which is inserted into the shaft 8 and is positioned exactly above the circuit board 4 with sensors, as will be explained further below.

[0024] The insertion depth of the holding device 11 in the nozzle 8 is limited by a collar 12, which in turn sits on a receptacle 13 on the circuit board 4.

[0025] Based on the Figures 2 and 3 A first embodiment of a light guide arrangement 18 is described.

[0026] The optical fiber assembly 18 comprises two optical fibers 19, 20, which are integrally manufactured with a ring 21 and radially connected to it on the outside. The optical fibers 19, 20 taper towards the sensors on the circuit board 4 to cross-sections 22, 23, which essentially correspond to the active area of ​​the sensors.

[0027] The light guide assembly 18 is located within the nozzle 8 in a holding device 25 according to the Figures 4 The optical fibers 19 and 20 are clearly trapped on the ring 21. The ring 21 is flush with the holding device 25 on its upper surface and is positioned by it directly below the disk 9.

[0028] Furthermore, each light guide 19,20 is precisely fitted into the circumferential and radial inner recesses of the holding device 25 by contact surfaces 26-28 and held against the inner wall of the nozzle 8 over its axial length.

[0029] The insertion depth of the retaining device 25 with the light guide assembly 18 into the nozzle 8 is limited by a collar 29. The collar 29 is provided with an arrowhead 30 which engages its counterpart in the upper shell 6, thus ensuring easy and rotationally secure insertion of the retaining device 25 with the light guide assembly 18 into the shaft 8 due to the springs 31-33 engaging in grooves of the nozzle 8, and thus also ensuring precise positioning of the lower light guide ends via corresponding sensors.

[0030] The top view according to Figure 5 The figure further shows that the holding device 25 forms a channel 34 which is axially parallel to the nozzle and open to the inner wall of the nozzle 8. A radiator located below can radiate its energy through the channel.

[0031] The side view according to Figure 4The underside of the coil shows 29 tubular casings, one of which, casing 35, can sit directly on a radiator, thus largely preventing lateral emission. In contrast, casings 36 and 37 radially seal off the light guides 19 and 20 to the outside.

[0032] The holding device 25 with the light guide arrangement 18 sits directly on a receptacle 40 according to the Figures 6 and 7 The sheaths 36, 37 enclosing the light guides 19, 20 engage in recesses 41, 42 and terminate there directly above sensors not shown. The sheath 35 terminates freely above a light source, whereby the arrangement of the light-sensitive sensors in the recesses 41, 42 ensures that they are not affected by the emitted energy of the light source.

[0033] The side view according to Figure 6Figure 43 shows a rising cylinder 43 of the receptacle 40 with a ring collar 44. A sensor (not shown) can be inserted into the shaft 43, resting on the ring collar 44 and aligned by the engagement of a lug of the sensor in a slot 45. The sensor then terminates at the top below the ring 21, the clear width of which preferably corresponds to the diameter of the active area of ​​the sensor.

[0034] On its underside, the receptacle 40 has three pins 46-48 which engage in corresponding recesses in the circuit board 4. This ensures precise positioning of the receptacle 40, the holding device 25, and the light guide assembly 18 relative to each other and to the sensors or emitters arranged on the circuit board 4.

[0035] Based on the Figures 8 to 13 A further embodiment of a detector device according to the invention is explained.

[0036] The light guide arrangement 50 according to the Figures 8 and 9In addition to the radially outer light guides 51,52 according to the preceding embodiment, it has a central third light guide 53, which also tapers substantially conically towards a sensor.

[0037] The central light guide 53 closes the in Figure 9 the indicated ring 54 and is formed in one piece with this and the two other light guides 51,52.

[0038] Accordingly, the holding device 55 forms according to the Figures 10 and 11 centrally, a funnel-shaped mounting surface 56 is provided for the central light guide 53.

[0039] This eliminates entry 57 according to the Figures 12 and 13 the cylinder of the previous embodiment and the tubular covering 59, which protrudes from the underside of the collar 58 of the holding device 55 and encloses the light guide 53, engages in the recess 60 of the receptacle 57.

[0040] The drawing does not show that the mounting surfaces of the fixtures are designed to be reflective for enclosing the light guides.

Claims

1. An optical detector device (1) comprising a housing (2) having a protruding neck (8) which is closed outwardly by a light-permeable pane (9), an optical waveguide arrangement (18)which is configured in one piece being arranged therebelow with a plurality of optical waveguides (19, 20) which are held in the neck (8) by a holding device (25), wherein each optical waveguide tapers toward a different sensor and the optical waveguide arrangement (18)comprises a central ring (21, 54) below the pane (9), wherein the ring (21, 54) is positioned on the holding device (25), the optical waveguides (19, 20)are radially outwardly connected to thering (21, 54) and the holding device encompasses the optical waveguides with an exact fit, in that each optical waveguide (19, 20) is encompassed by bearing surfaces (26 - 28) of cut-outs (38) of the holding device (25) in the peripheral direction and radially internally with an exact fit and is held against the inner wall of the neck (8) over the axial length thereof.

2. The detector device according to Claim 1, characterised in that the ring (54) is closed by a central optical waveguide (53).

3. The detector device according to one or more of the preceding claims, characterised in that the holding device (25) is configured in one piece.

4. The detector device according to one or more of the preceding claims, characterised in that the holding device (25) is non-rotatably and uniquely inserted into the neck (8) and that the optical waveguide arrangement (18) is non-rotatably and uniquely captured in the holding device (25).

5. The detector device according to one or more of the preceding claims, characterised in that at least bearing surfaces of the holding device on the optical waveguides are configured to be reflective.

6. The detector device according to one or more of the preceding claims, characterised in that the holding device (25)comprises a flange (29) defining the insertion depth in the neck (8), that the flange (29) is positioned on a receiver (40) on a printed circuit board (4) and that the receiver (40)comprisescut-outs (40 - 41) in which sensors or emitters are arranged.

7. The detector device according to Claim 6, characterised in that tubular sheaths (36, 37) encompassing the optical waveguides (19, 20) protrude below the lower face of the flange (29).

8. The detector device according to Claim 6 or 7, characterised in that pins (46 - 48),which engage in cut-outs of the printed circuit board (4) comprising an electronic evaluation system, protrude below the lower face of thereceiver (40).

9. The detector device according to one or more of the preceding Claims 6 to 8, characterised in that the receiver (40)comprises a cylinder (43) which passes centrally through the holding device (25) and that a sensor is held below the pane (9) by the cylinder (43).

10. The detector device according to one or more of the preceding claims, characterised in that the holding device (25) forms a channel (34) which is axially parallel to theneck (8) above an emitter.

11. The detector device according to one or more of the preceding claims, characterised in that the spectrum from infrared to ultraviolet is monitored by the use of a plurality of sensors and / or emitters.