Sensor holder and maintenance method for a flow sensor

Abstract

The invention discloses a sensor holder (10) for a flow sensor (20) and a maintenance method, the sensor holder comprising a substantially cylindrical housing (11) having a housing interior (12) with an opening (13) at a first front face designed to receive a flow sensor, the housing being conical (1) at a second front face, i.e. the front face opposite the first front face, the housing having a first flushing opening (8) leading into the housing interior, the opening opening into an end region of the cone (1), the housing having a second flushing opening (9) leading into the housing interior, a fastening unit (3) designed to fasten the flow sensor to the housing, and a first wall holder (30) designed to be fastened to a wall (41), the first wall holder comprising a joint (2) in the region of the second front face, the joint being connected to the housing, the housing being movable from a measurement position to a maintenance position via the joint.

Description

TECHNICAL FIELD

[0001] The invention relates to a sensor holder for a flow sensor and to a method for its maintenance. BACKGROUND

[0002] Sensors for liquid analysis are usually designed as immersion sensors which are applied to an open basin. On the other hand, there are flow containers for processes in which the medium is under pressure in a pipe. The sensor measures the flow and is therefore called a flow sensor.

[0003] The sensor and the flow container can become soiled during operation. In order to clean sensitive areas of the sensor, the flow container usually has a cleaning nozzle. Thus, automatic cleaning can be carried out using compressed air or a liquid cleaning medium. Due to the process medium and the air cleaning, air bubbles can interfere with the measurement or large amounts of air can accumulate in the flow container. In order to remove stubborn dirt, the disassembly of the sensor must be as simple as possible. In this respect, it must be taken into account that the unit consisting of the flow container and the sensor is usually installed in a protective cabinet with very limited space conditions. SUMMARY

[0004] The invention is based on the object of making the flow container easy to maintain under limited space conditions, wherein the flow container should also be suitable for bubble-free measurement.

[0005] This object is achieved by a sensor holder for a flow sensor, comprising a substantially cylindrical housing having a housing interior, which has an opening at a first front, which is designed to receive a flow sensor, wherein the housing is conical at a second front, which is the front opposite the first front, the housing has a first flushing opening, which opens into the housing interior, which opens into an end region of the cone, the housing has a second flushing opening, which opens into the housing interior, a fastening unit, which is designed to fasten the flow sensor to the housing, and a first wall holder, which is designed to be fastened to a wall, wherein the first wall holder comprises a joint in the region of the second front, which is connected to the housing, wherein the housing can be moved from a measurement position to a maintenance position via the joint.

[0006] Thus, the sensor can be easily disassembled under limited space conditions while ensuring pressure resistance. This leads to easy maintenance, primarily easy cleaning of the interior, and easy replacement or cleaning of the seals.

[0007] In this case, the material, surface quality and profile of the sensor holder are chosen such that the liquid volume is as small as possible and the measured variable is not influenced by a wall effect. This design should also counteract the accumulation of dirt as much as possible.

[0008] One embodiment provides that the sensor holder comprises a second wall holder, which is designed to be fastened to the wall; in particular, the second wall holder is arranged at an offset from the first wall holder,

[0009] wherein the second wall holder comprises a receptacle for the flow sensor.

[0010] One embodiment provides that the first wall holder comprises a damper, which damps the movement of the housing from the measurement position to the maintenance position.

[0011] One embodiment provides that the first wall holder with the joint is designed and in particular also together with the second wall holder is designed such that the longitudinal axis of the housing is arranged at an angle to the longitudinal direction, which is > 5°, in particular between 5° and 45°, in particular between 5° and 20°.

[0012] One embodiment provides that the sensor holder comprises a cleaning opening to the interior of the housing, which is arranged such that, in the installed state of the flow sensor, it points to the sensitive area of the flow sensor.

[0013] One embodiment provides that the fastening unit is a union nut and the housing has a corresponding outer thread in the region of the first front face.

[0014] One embodiment provides that the sensor holder comprises a holder, in particular a ring-shaped holder, which is designed to be fixed to or around the flow sensor, wherein the holder is designed to be attached to the housing at the first front face, wherein the fastening unit engages in the holder and prevents the flow sensor mounted in the sensor holder from moving.

[0015] One embodiment provides that the holder comprises a collar, wherein the union nut is supported on the collar, whereby the holder is pressed onto the housing and the flow sensor is prevented from moving.

[0016] One embodiment provides that the sensor holder comprises a sealing element, which is designed to prevent a flow of medium from the interior of the housing to the outside, wherein the housing has a recess in the region of the first front face, into which the sealing element can be inserted.

[0017] One embodiment provides that the sealing element is ring-shaped and comprises a first O-ring on the inner side thereof and a second O-ring on the outer side thereof.

[0018] One embodiment provides that the flow sensor is an optical sensor, in particular a fluorescence sensor, in particular for determining the oil-in-water content; a turbidity sensor; an oxygen sensor.

[0019] Furthermore, the object is achieved by a method for maintaining a flow sensor in the sensor holder described above, comprising at least the following steps: moving the housing from the measuring position to the maintenance position via the joint; releasing the fastening unit, in particular the union nut; removing the holder with the flow sensor attached from the interior of the housing; removing the sealing element; optionally, cleaning or replacing the sealing element; cleaning the interior of the housing and, if necessary, cleaning the first flushing opening and / or the second flushing opening and / or the cleaning opening; optionally, cleaning the holder and the flow sensor; attaching the sealing element; attaching the holder with the flow sensor; attaching the fastening unit; and moving the housing to the measuring position.

[0020] The claimed sensor holder and the claimed method minimize the volume of the flow cell without affecting the measurement signal, which makes it easiest to maintain under limited space conditions and enables effective protection against measurement errors due to air bubbles, while enabling rapid measurements after compressed air cleaning. BRIEF DESCRIPTION OF DRAWINGS

[0021] This will be explained in more detail with reference to the following drawings.

[0022] Figure 1 A cross-sectional view of the claimed sensor holder is shown.

[0023] Figure 2 A claimed sensor holder with a second wall holder is shown.

[0024] Figure 3 A claimed sensor holder is shown, in which the sensor is in the measuring position.

[0025] Figure 4 A flow sensor is shown.

[0026] Figure 5 A sensor holder with a transmitter is shown in a protection cabinet.

[0027] Figure 6 A cross-sectional exploded view of the claimed sensor holder is shown.

[0028] Figure 7 A holder in the fastening unit is shown.

[0029] Figure 8 A sealing element is shown.

[0030] Figure 9 A partial cross-sectional exploded view of the claimed sensor holder with a second wall holder is shown.

[0031] In the drawings, identical features are identified with the same reference numerals. DETAILED DESCRIPTION

[0032] The overall claimed sensor holder is denoted by reference numeral 10 and is shown in Figure 1 cross-section without the sensor 20.

[0033] The sensor holder 10 comprises a substantially cylindrical housing 11 having a housing interior 12. On a first side, at the top of Figure 1 the sensor holder 10 has an opening 13 leading into the interior 12 into which the flow sensor 20 can be inserted. The housing 11 is conical on the opposite side. This is denoted by reference numeral 1. The conical design prevents light reflection and avoids dirt accumulation.

[0034] The housing 11 comprises a first flushing opening 8 leading into the housing interior 12, which opens into the end region of the cone 1, and a second flushing opening 9. Through the first flushing opening, a flushing / calibration or cleaning medium is introduced into the interior 12, and the medium exits the interior 12 again through the second flushing opening.

[0035] The sensor holder 10 comprises a fastening unit 3 which is designed to fasten the flow sensor 10 in the housing 11. The fastening unit is, for example, a union nut 3, wherein the housing 11 has a corresponding outer thread 14 in the region of the first front face 13. In one embodiment, the fastening unit 3 comprises one or more radial openings, for example as threads, through which one or more screws can be guided, wherein corresponding openings, for example threads, are arranged in the housing 11. Likewise, the radially inner retaining piece 4 (see below) can have corresponding openings, for example threads. The sensor 20 can also have corresponding receiving means. The sensor can thus be fixed in / on the housing.

[0036] The retaining piece 4, in particular an annular retaining piece, is designed to be fixed to or around the flow sensor 20. To this end, the sensor 20 comprises a marking 21, in particular a factory-applied marking, in order for the user to know exactly at what position the retaining piece 4 must be attached to the sensor 20; see Figure 4 . The marking 21 is applied to the sensor 20, for example by laser marking or embossing, such that the thus arranged sensor 20 is located in the sensor holder 10 with the aid of the retaining piece and its sensitive region 22 is at the level of the cleaning opening 16. To this end, the retaining piece 4 is designed such that it can be attached to the housing 11 at the first front face 13. The fastening unit 3, i.e. for example the union nut, engages in the retaining piece 4, thereby preventing the flow sensor 20 mounted in the sensor holder from moving.

[0037] Via the cleaning opening 16, compressed air can be directed onto the sensitive area 23 of the sensor 20 in order to remove any residues present. The cleaning opening 16 has a nozzle shape with a suitable orientation, i.e. with a corresponding angle, in order to effectively remove contamination from the central sensor window.

[0038] The holder 4 comprises a collar 17, wherein the union nut 3 is supported on the collar 17, whereby the holder 4 is pressed against the housing 11 and prevents the flow sensor 20 from moving. Figure 6 An exploded view is shown. In Figure 6 The collar 17 of the holder 4 can be seen. The union nut 3 comprises a kind of overhang or a corresponding matching portion with a smaller inner diameter.

[0039] Figure 7 An isolated view of the union nut 3 and the holder is shown, but in the assembled state.

[0040] In the region of the first front face 13, the housing 11 has a recess 18 into which the sealing element 6 can be inserted. The recess 18 directly adjoins the upper edge of the housing 11, i.e. on this side of the opening 13. The sealing element 6 is designed to prevent the medium from flowing from the interior 12 of the housing to the outside. The sealing element 6 can be designed as an O-ring or as a sealing band. In Figure 1 In one embodiment shown in Figure 8 An isolated view of the sealing element 6 is shown; Figure 6 The sealing element is shown as part of an exploded view.

[0041] In the lower region, i.e. on this side of the cone 1, the sensor holder 10 comprises a first wall holder 30 which is designed to be fixed to the wall 42. In this case, the first wall holder 30 comprises a joint 2, e.g. a hinge, which is connected to the housing 11, wherein the housing 11 can be moved via the joint 2 from the measuring position to the maintenance position. The first wall holder 30 with the joint 2, especially also together with the second wall holder 31 (see below), is designed such that the longitudinal axis of the housing 11 is arranged at an angle to the vertical, i.e. to the wall 42, which is > 5°, especially between 5° and 45°, especially between 5° and 20°. The slightly inclined sensor assembly and the annular bubble trap 7 prevent the accumulation of air or bubbles. In the bubble trap 7, air can accumulate in the ring without impairing the sensor function. For this purpose, the sensor front must be pushed at least as far forward as the center of the annular groove. This can prevent bubbles from accumulating in front of the sensor. Furthermore, this ensures that air introduced due to the root cause, i.e. from compressed air cleaning, is discharged as quickly and effectively as possible.

[0042] By folding the housing 11 together with the sensor 20 down to the maintenance position, the joint 2 makes it possible to easily detach the sensor 20 with the union nut 3 even under limited space conditions in the protective housing 40. In Figure 5 In the middle, the transmitter 41 connected to the sensor 20 is visible in the protective housing 40, wherein the sensor 20 is in the measuring position in this figure.

[0043] For example, the following materials are selected: housing 11 made of PE, union nut 3 made of PE, sealing element 6 made of PVDF, and holder 4 made of PE.

[0044] Figure 2 The sensor holder with the first and second wall holders 30, 31 is shown (at the bottom / top in the figure). The sensor holder 10 comprises a second wall holder 31 which is designed to be fastened to the wall 42. The second wall holder 31 is arranged at an offset from the first wall holder 30, wherein the second wall holder comprises a receptacle 32 for the flow sensor 20, which receptacle has a locking or latching action as required. The sensor 20 can be locked, e.g. clipped or latched, in the receptacle.

[0045] The first wall holder 30 comprises a bumper 5 which brakes the movement of the housing 11 from the measuring position to the maintenance position. The bumper, e.g. a rubber bumper 5, limits the angle of the longitudinal axis of the housing 11 to the vertical such that even in the maintenance position no liquid from the interior 12 can leak.

[0046] Figure 3It is shown that the sensor 20 is mounted in the sensor holder 10 in the measuring position, wherein the two wall holders 30, 31 are fastened to the wall 42.

[0047] Figure 9 It is shown that the sensor holder 10 with the sensor 20 is received in the second wall holder 31. The sensor 20 is enclosed by the union nut 3, which engages in the thread 14 during assembly, thus fixing the sensor.

[0048] The sensor 20 is discussed below; see Figure 4 or Figure 9 The sensor is, for example, an optical sensor, in particular a fluorescence sensor, in particular for determining the oil-in-water content; a turbidity sensor; an oxygen sensor.

[0049] The sensor 20 comprises a light source. The light source radiates excitation light into the medium to be measured in the interior 20, wherein the excitation light is converted by the medium into fluorescence. The fluorescence is received by a photodiode and converted into a first signal. The photodiode measures the decay curve of the fluorescence. Alternatively or in addition, the fluorescence intensity is measured directly after excitation. The decay time is determined via the decay curve. The decay time obtained is an integral value without spectral information. The feature "determining the decay curve" also means determining the decay time by measuring the phase shift in the case of periodic excitation. Alternatively or in addition, the fluorescence can also be captured by a spectrometer. The spectrometer measures the spectrum of the fluorescence and converts it into a second signal. The light source, the spectrometer and the photodiode together with the transmitter 41 determine the oil-in-water content of the sample from the first signal and / or the second signal. The concentration is determined by a calibration model which combines the measured information about the decay time in discrete wavelength intervals and about the fluorescence intensity and determines the concentration therefrom. Additional information about the oil is included in the spectral distribution of the fluorescence, its decay time and its dependence on the excitation wavelength.

[0050] The maintenance procedure for sensor 20 can be as follows: First, housing 11 is moved from the measurement position to the maintenance position via connector 2. In doing so, sensor 20 is detached from the second wall bracket 31 or released from opening 32. The clamps must be opened if necessary. If sensor 20 (and housing 11) is in the maintenance position, the fastening unit 3, i.e., the connecting nut, is released. Then, sensor 20 is removed from bracket 10. Retainer 4 can remain on sensor 20. Finally, sealing element 6 can be removed. The sealing element is cleaned or completely replaced, or one or both O-rings are replaced. This is followed by cleaning the inside of housing 12, and, if necessary, cleaning the first and / or second flushing openings 8, 9 and / or cleaning opening 16. Since sensor 20 is disassembled, sensor 20 and retainer 4 can be cleaned. Finally, assembly is performed in reverse order: first attaching sealing element 6, then attaching retainer 4 and flow sensor 20 together, attaching and tightening the connecting nut, and finally, moving housing 11 (i.e., housing 11 of sensor 20) to the measurement position.

[0051] List of reference numerals

[0052] 1. Conical region

[0053] 2. Joints and hinges

[0054] 3. Fastening unit, connecting nut

[0055] 4. Retaining components

[0056] 5 Buffers

[0057] 6 Sealing elements

[0058] 6a O-ring

[0059] 6b O-ring

[0060] 7. Bubble trap

[0061] 8 First flushing opening

[0062] 9 Second flushing opening

[0063] 10 Sensor bracket

[0064] 11. Outer shell

[0065] 12 11 interior

[0066] 13 for openings in 20

[0067] 14 External thread

[0068] 16 Cleaning opening

[0069] 17 4 collar

[0070] 18 recess

[0071] 20 flow sensor

[0072] 21 marking

[0073] 22 sensitive area of 20

[0074] 30 first wall bracket

[0075] 31 second wall bracket

[0076] 31 receptacle for 20 in 31

[0077] 40 protective housing

[0078] 41 transmitter

[0079] 42 wall

Claims

1. Sensor holder (10) for a flow sensor (20), the sensor holder (10) comprising: a substantially cylindrical housing (11) having a housing interior (12) and having an opening (13) at a first front face, the opening (13) being designed to receive the flow sensor (20), wherein the housing (11) is a cone (1) at a second front face, the second front face being the front face opposite the first front face, a first flushing opening (8) leading into the housing interior (12), the first flushing opening (8) opening into an end region of the cone (1), a second flushing opening (9) leading into the housing interior (12); a fastening unit (3) designed to fasten the flow sensor (20) in the housing (11), and a first wall holder (30) designed to be fastened to a wall (42), wherein the first wall holder (30) comprises a joint (2) connected to the housing (11) in the region of the second front face, wherein the housing (11) is movable via the joint (2) from a measurement position to a maintenance position.

2. Sensor holder (10) according to claim 1, comprising: a second wall holder (31) designed to be fastened to a wall (42), wherein the second wall holder (31) comprises a receptacle for the flow sensor (20).

3. Sensor holder (10) according to claim 1 or 2, wherein the first wall holder (30) comprising a damper (5) which brakes the movement of the housing (11) from the measurement position to the maintenance position.

4. Sensor holder (10) according to claim 2, wherein the first wall holder (30) with the joint (2) being designed such that a longitudinal axis of the housing (11) is arranged at an angle to the vertical, the angle being > 5°.

5. Sensor holder (10) according to claim 1 or 2, comprising: a cleaning opening (16) leading into the housing interior (12), the cleaning opening (16) being arranged such that, in the installed state of the flow sensor (20), it points to a sensitive region (22) of the flow sensor (20).

6. Sensor holder (10) according to claim 5, wherein the fastening unit (3) being a union nut and the housing (11) having a corresponding external thread (14) in the region of the first front face.

7. Sensor holder (10) according to claim 6, comprising: a holder (4) designed to be fixed to or around the flow sensor (20), wherein the holder (4) is designed to be attached to the housing (11) at the first front face, wherein the fastening unit (3) engages in the holder (4) and prevents the flow sensor (20) mounted in the sensor holder (10) from moving.

8. Sensor holder (10) according to claim 7, wherein, the holder (4) comprises a collar (17), wherein the union nut is supported on the collar (17), whereby the holder (4) is pressed onto the housing (11) and the flow sensor (20) is prevented from moving.

9. Sensor holder (10) according to claim 8, comprising: a sealing element (6) which is designed to prevent a medium from flowing from the housing interior (12) to the outside, wherein the housing (11) has a recess (18) in the region of the first front face, into which the sealing element (6) can be inserted.

10. Sensor holder (10) according to claim 9, wherein, the sealing element (6) is ring-shaped and comprises a first O-ring on its inner side and a second O-ring on its outer side.

11. Sensor holder (10) according to claim 1 or 2, wherein, the flow sensor (20) is one of the following sensors: optical sensor; turbidity sensor; oxygen sensor.

12. Sensor holder (10) according to claim 2, wherein the second wall bracket (31) is arranged at an offset from the first wall bracket (30).

13. Sensor holder (10) according to claim 4, wherein, the angle is between 5° and 45°.

14. Sensor holder (10) according to claim 4, wherein the angle is between 5° and 20°.

15. Sensor holder (10) according to claim 11, wherein the flow sensor (20) is an optical sensor, which is a fluorescence sensor.

16. Sensor holder (10) according to claim 11, wherein the flow sensor (20) is an optical sensor for determining the oil-in-water content.

17. Sensor holder (10) according to claim 2, wherein the first wall bracket (30) with the joint (2) is designed together with the second wall bracket (31) such that the longitudinal axis of the housing (11) is arranged at an angle to the vertical, the angle being > 5°.

18. Sensor holder (10) according to claim 17, wherein the angle is between 5° and 45°.

19. Sensor holder (10) according to claim 17, wherein the angle is between 5° and 20°.

20. The sensor support (10) according to claim 7, wherein the holder is a ring-shaped holder.

21. Method for servicing a flow sensor (20) in a sensor holder (10) according to claim 9, the method comprising the following steps: moving the housing from the measurement position to the servicing position via the joint (2); releasing the fastening unit (3); removing the holder (4) with the flow sensor (20) attached from the housing interior (12); removing the sealing element (6); cleaning the inside of the housing (12) and, if necessary, the first and / or second flushing opening (9) and / or the cleaning opening (16); attaching the sealing element (6); attaching the holding piece (4) together with the flow sensor (20); attaching the fastening unit (3); and moving the housing into the measuring position.

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