JP2024046589A - Water detection sensor unit and fuel supply device - Google Patents

Abstract

[Problem] With the distance between a transmitter 33 and a receiver 34 of a sensor that detects water in fuel accurately adjusted, the transmitter 33 and the receiver 34 can be attached across a flow path 35b through which the fuel passes. [Solution] A water detection sensor unit 30 that detects water in fuel supplied to a fuel supply target includes a transmitter 33 that transmits a signal to the fuel, a receiver 34 that receives the signal that has passed through the fuel, and a resin holder 35 having a sensor housing chamber 35c in which the transmitter 33 is housed, a sensor housing chamber 35d in which the receiver 34 is housed, and a flow path 35b formed between the sensor housing chamber 35c and the sensor housing chamber 35d and through which the fuel passes. [Selected Figure] Figure 3

Description

The present invention relates to a water detection sensor unit that detects water in fuel supplied to a fuel supply target, and a fuel supply device equipped with the water detection sensor unit.

Patent document 1 discloses a technology in which a water detection sensor consisting of a pair of light-projecting and light-receiving parts is provided in the fuel supply path, and the water content in the fuel present between the light-projecting and light-receiving parts is detected.

JP 2020-121754 A

In a water detection sensor, light (electromagnetic waves) emitted from a light-emitting unit (transmitter) passes through the fuel and is received by a light-receiving unit (receiver), and the amount of water in the fuel passing between the light-emitting unit and the light-receiving unit is detected from the intensity of the light (electromagnetic waves) received by the light-receiving unit. For this reason, if the distance between the light-emitting unit and the light-receiving unit is made small, the width of the fuel passing between them becomes small, making it impossible to accurately detect the amount of water in the fuel. Also, if the distance between the light-emitting unit and the light-receiving unit is made large, the light emitted from the light-emitting unit is significantly attenuated as it passes through the fuel, and in some cases, the light-receiving unit may not be able to receive the light. Therefore, it is very important to adjust the distance between the light-emitting unit and the light-receiving unit, and when attaching the light-emitting unit and the light-receiving unit to the fuel supply path, it is necessary to accurately adjust the distance between the light-emitting unit and the light-receiving unit before attaching them. However, this adjustment process is time-consuming.

The present invention makes it possible to install the transmitter and receiver across the flow path through which the fuel passes, while accurately adjusting the distance between the transmitter and receiver of the sensor that detects water in fuel. A water detection sensor unit and a fuel supply device including the water detection sensor unit are provided.

The water detection sensor unit of the present invention is a water detection sensor unit that detects water in fuel supplied to a fuel supply target, and includes a transmitter that transmits electromagnetic waves and a receiver that receives the electromagnetic waves transmitted from the transmitter. a first sensor housing part in which the transmitter is housed, a second sensor housing part in which the receiver is housed, and between the first sensor housing part and the second sensor housing part. and a first holder having a flow path.

According to the present invention, the transmitter and the receiver can be installed across the flow path through which the fuel passes, with the distance between the transmitter and receiver of the sensor that detects water in fuel being accurately adjusted. I can do it.

FIG. 1 is a schematic configuration diagram of a refueling device according to an embodiment. FIG. 3 is an explanatory diagram of a fuel supply path in the pump unit according to the embodiment. (a) A perspective view of a water detection sensor unit attached to a casing of a pump unit according to an embodiment, and (b) an exploded perspective view of the water detection sensor unit according to an embodiment. FIG. 2A is a side view of a pump unit according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. 3A is a perspective view, FIG. 3B is a side view, FIG. 3C is a front view, FIG. 3D is a rear view, and FIG. 1A is a perspective view of a water detection sensor unit according to an embodiment, and FIG. 1B is a view of the water detection sensor unit of FIG. 1A without a metal holder. It is a sectional view of the metal holder concerning a modification. (a) A perspective view of a water detection sensor unit attached to a casing of a pump unit according to Example 2, and (b) an exploded perspective view of the water detection sensor unit according to Example 2. FIG. 3 is a cross-sectional view of a water detection sensor unit according to Example 2. FIG. 11 is a front view of a metal holder according to a second embodiment. FIG. 3 is a cross-sectional view of a metal holder according to Example 2.

Embodiments of the present invention will be described in detail based on the drawings. It goes without saying that, in the following embodiments, the constituent elements are not necessarily essential, except when specifically specified or when it is considered to be clearly essential in principle.

An embodiment of the fuel supply device according to the present invention is installed at a gas station or other gas station, and the tip of the refueling nozzle is inserted into the fuel filler port of a vehicle, etc., and the fuel supply device replenishes the vehicle with fuel such as gasoline or diesel oil. This will be explained using a device as an example.

FIG. 1 is a schematic configuration diagram of a refueling device according to an embodiment.

(Lubrication device 1)
In the illustrated example, the refueling device 1 is a ground-mounted refueling device. The fuel supply device 1 includes a pump 11 driven by a pump motor 12 and a flow meter 13 that measures the amount of fuel discharged from the pump 11 in a fuel supply device main body 2. Further, an internal pipe 15 is connected to the outflow side of the flow meter 13, and a refueling hose 16 to which a refueling nozzle 17 is connected is connected to the tip of the internal pipe 15. The suction side of the pump 11 is connected via an underground pipe 21 to a liquid in an underground tank 22 that stores fuel oil liquid.

In the fuel supply system 1, the fuel oil liquid pumped up from the underground tank 22 by the pump 11 is supplied to the flow meter 13, and the amount of the liquid is measured. A flow rate transmitter 14 is attached to the flow meter 13, and outputs a flow rate pulse proportional to the flow of fuel oil per unit flow rate.

The refueling nozzle 17 is stored in a nozzle storage section 18 provided in the refueling device main body 2 when it is not used for refueling work. During refueling work, the refueling nozzle 17 is taken out from the nozzle housing 18, the discharge pipe at the tip is inserted into the refueling port of the vehicle, etc., the built-in on-off valve is opened by operating the operating lever, and the fuel is dispensed. Replenishment is now available. The nozzle storage section 18 is provided with a nozzle switch 19 for detecting whether the refueling nozzle 17 is taken out or put back on. Refueling information such as the amount of refueling during refueling work is displayed on a display 20 provided with its display surface facing outside from the refueling device main body 2.

In addition to devices such as the pump 11 and flow meter 13, the fuel supply device main body 2 is provided with a control device 23 that controls each part of the fuel supply device 1. The control device 23 is configured to include a microcomputer device equipped with a processor, memory, input/output interface, etc. Detection signals from the nozzle switch 19 and the like are input to the control device 23, and each part of the fuel supply device 1 is controlled based on these signal inputs.

Specifically, the control device 23 drives the pump motor 12 when the fuel nozzle 17 is removed from the nozzle storage section 18 based on a detection signal from the nozzle switch 19, and stops driving the pump motor 12 when the fuel nozzle 17 is returned to the nozzle storage section 18. In addition, the control device 23 calculates the amount of fuel added during the fueling operation based on the input of flow rate pulses from the flow rate transmitter 14, and displays the amount on the display 20.

Furthermore, in the refueling device 1, the control device 23 is connected to a POS terminal (point of sale information management device) for the refueling station (not shown) via a local area network within the refueling station (so-called refueling station LAN), and based on receiving a refueling operation permission signal or a refueling operation prohibition signal supplied from the POS terminal for the refueling station, it permits or prohibits the operation of each part of the device, including the drive of the pump motor 12 based on the operation of the refueling nozzle 17 described above, and when the refueling operation is completed, it transmits refueling information such as the amount of fuel dispensed to the POS terminal for the issuance of a receipt, etc.

In addition to the above-mentioned configuration, the fuel supply device 1 according to the embodiment includes a water detection sensor unit 30 provided in the fuel supply path from the underground tank 22 to the fuel supply nozzle 17. The water detection sensor unit 30 detects the amount of water or the presence or absence of water mixed in the fuel pumped up from the underground tank 22 by the pump 11 and supplied to the fuel supply nozzle 17.

Based on the detection output of the water detection sensor unit 30, the control device 23 detects whether or not water is abnormally mixed into the fuel supplied to the fuel supply target, such as a vehicle. In order to prevent the fuel mixed with the fuel from being supplied, the drive of the pump motor 12 is stopped.

(Pump unit 40)
In this embodiment, the water detection sensor unit 30 is provided in the pump unit 40. The pump unit 40 is configured such that the pump 11 is disposed in the same casing together with a strainer provided in the fuel supply path on the suction side of the pump 11 and an air separator and a filter provided in the fuel supply path on the discharge side of the pump 11.

Next, the pump unit 40 in which the water detection sensor unit 30 is provided will be described with reference to FIG. 2. FIG. 2 is an explanatory diagram of the fuel supply path in the pump unit according to the embodiment.

In FIG. 2, in order to clearly show the overall configuration of the pump unit 40, the relative positions of the various parts within the casing 41 are shown shifted vertically, front-to-back, and left-to-right from the actual positions.

As shown in FIG. 2, the pump unit 40 has a casing 41 with an inlet 42 and an outlet 43, inside which a strainer mounting chamber 44, a check valve mounting chamber 45, a rotor chamber 46, an air separation chamber 47, a sensor unit housing chamber 48, and a filter chamber 49 are arranged in sequence from the upstream side to the downstream side of the fuel supply path, and in addition, a gas-liquid separation chamber 50 is arranged to communicate between the air separation chamber 47 and the inlet side of the rotor chamber 46.

A strainer 51 is attached to the strainer attachment chamber 44 . The strainer attachment chamber 44 communicates with an inlet 42 that opens at the bottom of the casing 41 .

The strainer 51 is made of a mesh member that captures foreign matter (solid foreign matter other than water) contained in the fuel oil liquid flowing in from the inlet 42, and is formed into a hollow cylindrical shape from a conductive metal mesh member. The strainer 51 is inserted into the chamber from the strainer mounting opening 44a. The strainer mounting cover 52 is fastened to the casing 41 so as to liquid-tightly close the strainer mounting opening 44a of the strainer mounting chamber 44, and holds the strainer 51 in the strainer mounting chamber 44. The fuel oil liquid sucked from the inlet 42 by the operation of the pump 11 is introduced into the cylindrical interior of the strainer 51 along the axial direction of the strainer 51.

The fuel oil liquid sucked from the inlet 42 by the operation of the pump 11 is filtered by the strainer 51 and then flows into the check valve mounting chamber 45. The check valve mounting chamber 45 is provided downstream of the strainer mounting chamber 44 and is formed adjacent to the strainer mounting chamber 44 inside the casing 41. The two chambers 44, 45 are connected to each other. An inlet side check valve 54 is attached to the check valve mounting chamber 45 so that it can be opened and closed. The fuel oil liquid that passes through the inlet side check valve 54 flows out into the suction side flow path 57 that communicates with the rotor chamber 46 in which the gear pump 61 is provided.

The inlet check valve 54 is biased toward the strainer 51 by the spring force of the coil spring 55. When the pump is operating, the pump suction pressure (negative pressure) opens the communication opening 45c, and when the pump is stopped, the pump suction pressure disappears and the communication opening 45c closes.

A rotor chamber 46 is provided on the downstream side of the check valve mounting chamber 45 and is communicated with a suction side flow path 57 . A gear pump 61 is provided in the rotor chamber 46 as the pump 11. The gear pump 61 includes a rotor 62 that rotates in response to the rotational driving force of the pump motor 12, and a pinion 63 that is rotationally driven by the rotor 62.

The rotor 62 is formed in a disk shape with an outer diameter corresponding to the inner diameter of the rotor chamber 46, and multiple semicircular engagement parts 62a are provided at a predetermined pitch (interval) on the peripheral part of the disk surface in the rotational direction (circumferential direction). In contrast, the pinion 63 is rotatably supported by a rotating shaft 64, and multiple semicircular recesses 63a corresponding to the engagement parts 62a of the rotor 62 are provided at a predetermined pitch (interval) on the outer periphery.

The center of rotation of the rotor 62 and the axis of the rotating shaft 64, which is the center of rotation of the pinion 63, are eccentric along the inner diameter direction of the rotor chamber 46. In the gap between the outer periphery of the pinion 63 and the inner periphery of the rotor 62, which is the inscribed circle of each engagement portion 62a, a crescent-shaped partition portion 65 is provided according to the amount of eccentricity of the rotation center. The outer periphery of the pinion 63 slides against the inner periphery of the partition portion 65, and the engagement portion 62a of the rotor 62 slides against the outer periphery of the partition portion 65.

The engagement portion 62a of the rotor 62 engages with the recessed portion 63a of the pinion 63, so that when the rotor 62 is rotated by the motor, the pinion 63 is also rotated in the same direction. Then, due to the generation of negative pressure on the suction port 46a side of the rotor chamber 46 based on the rotation of the rotor 62 and pinion 63, the inlet check valve 54 opens, and the fuel oil liquid that has passed through the strainer 51 is sucked into the suction port 46a of the rotor chamber 46.

In the gear pump 61, the rotor 62 and pinion 63 rotate counterclockwise as shown in the figure, and the fuel oil liquid sucked from the suction side flow passage 57 flows into the recess 63a of the pinion 63 and into the gap between the engagement parts 62a of the rotor 62, and is discharged to the discharge side flow passage 66 connected to the discharge port 46b of the rotor chamber 46. The fuel oil liquid discharged from the gear pump 61 is connected via the discharge side flow passage 66 and flows into the air separation chamber 47 located further downstream in the fuel supply path.

The air separation chamber 47 has a structure that allows the inflowing fuel oil liquid to be separated into a gas-enriched liquid containing gas and a supplied fuel oil liquid containing less than a permissible amount of gas by using its centrifugal force and gravity. ing. Along with this, the upper chamber wall of the air separation chamber 47 where the separated gas-enriched liquid tends to collect is provided with a gas-enriched liquid outflow for collecting the separated gas-enriched liquid into the gas-liquid separation chamber 50. A hole 71 is provided. The gas-enriched liquid outflow hole 71 communicates between the upper part of the air separation chamber 47 where the gas-enriched liquid collects and the gas-liquid separation chamber 50.

On the other hand, the separated supply fuel oil liquid communicates with the lower part of the air separation chamber 47 where the supply fuel oil liquid collects, and a sensor unit housing chamber 48 in which the water detection sensor unit 30 is housed and a filter 72 are provided. After the foreign matter is filtered by the filter 72 , it flows into the outflow path 74 connected to the outflow port 43 of the casing 41 .

The sensor unit housing chamber 48 has a sensor mounting opening 48a provided on the side of the casing 41, and the water detection sensor unit 30 is disposed in the sensor unit housing chamber 48 through the sensor mounting opening 48a. Details of the water detection sensor unit 30 will be described later.

The filter chamber 49 has a filter attachment opening 49a provided on the side surface of the casing 41, as in the case of the strainer attachment chamber 44, and the filter 72 is arranged in the filter chamber 49 from the filter attachment opening 49a. will be established. The filter attachment lid 73 is fastened to the casing 41 so as to close the filter attachment opening 49a of the filter chamber 49, and holds the filter 72 in the filter chamber 49. The fuel oil that has flowed into the filter chamber 49 can flow out from the fuel oil outlet 49b to the outflow path 74 via the filter 72.

The outlet 43 of the casing 41 is connected in communication with the inlet of the flowmeter 13, so that only the supply fuel oil containing less than an allowable amount of gas can be supplied to the flowmeter 13. In addition, in the illustrated example, the outlet path 74 is provided with an outlet check valve 75 that opens due to the pressure of the fuel oil delivered by the gear pump 61. The outlet check valve 75 prevents the supply fuel oil from returning from the flowmeter 13 side to the pump unit 40 side.

The gas-liquid separation chamber 50 separates gas from the gas-enriched liquid that has flowed from the air separation chamber 47 through the gas-enriched liquid outflow hole 71 . A return hole 76 is provided at the bottom of the gas-liquid separation chamber 50 to return the fuel oil liquid to the suction port 46a side of the rotor chamber 46 of the gear pump 61, and the ceiling of the gas-liquid separation chamber 50 is provided to return the separated gas. An atmosphere opening hole 77 is provided for releasing the air to the outside.

The gas-liquid separation chamber 50 is provided with a float valve 78 that responds to the level of the fuel oil liquid containing the gas-enriched liquid in the gas-liquid separation chamber 50 . The float valve 78 is a valve portion that opens the return hole 76 when the liquid level of the fuel oil liquid containing the gas-enriched liquid accumulated in the gas-liquid separation chamber 50 reaches a predetermined height or more. has. In the gas-liquid separation chamber 50, bubbles (gas) contained in the gas-enriched liquid float to the space above the liquid level and are released into the atmosphere from the atmosphere opening hole 77. Further, when the liquid level reaches a predetermined level, the fuel oil liquid from which bubbles have been separated passes through the return hole 76 and is returned to the suction side flow path 57 by opening the float valve 78.

The casing 41 is provided with a relief passage 81 that connects the outflow side of the filter chamber 49 and the suction port 46a side of the rotor chamber 46, and the relief passage 81 is provided with a relief valve 82. When the hydraulic pressure of the fuel oil in the fuel supply path downstream of the pump 11, i.e., the pump unit 40, becomes higher than necessary, some or all of the fuel oil newly filtered by the filter 72 opens the relief valve 82 and is returned to the suction port 46a side of the rotor chamber 46 of the gear pump 61. The relief valve 82 is biased in the closing direction by the spring force of the coil spring 83, and opens and closes according to the difference between the hydraulic pressure in the outflow path 74 and the resultant force of the spring force of the coil spring 83 plus the suction pressure of the rotor chamber 46. During the operation of the gear pump 61, the relief valve 82 repeatedly opens and closes due to the balance between the spring force of the coil spring 83 and the resultant force of the discharge pressure and the suction pressure.

(Water detection sensor unit 30)
Next, the water detection sensor unit 30 will be described in detail with reference to Figures 3 and 4. As shown in Figure 3, the water detection sensor unit 30 has a cover 31, a water detection sensor board 32, a transmitter (sender) 33, a receiver (receiver) 34, a resin holder (first holder) 35, and a metal holder (second holder) 36. The water detection sensor board 32, the transmitter 33, the receiver 34, and the resin holder 35 (hereinafter, the water detection sensor board 32, the transmitter 33, the receiver 34, and the resin holder 35 will be referred to as the "water detection sensor assembly") are housed inside the cylindrical metal holder 36. In addition, hereinafter, the transmitter 33 and the receiver 34 will be referred to as the "sensor". The metal holder 36 housing the water detection sensor assembly is disposed in the sensor unit housing chamber 48 through the sensor mounting opening 48a. Then, the cover 31 is disposed so as to close the opening of the metal holder 36, and the cover 31 and the metal holder 36 are fixed to the casing 41.

(Lid 31)
The lid 31 closes the opening for introducing the water detection sensor assembly into the metal holder 36. The lid 31 is fixed to the casing 41. The lid 31 has a flange 31b in which a through hole 31a is formed, through which a fixing member 39 (see FIG. 6) such as a screw for fixing the lid 31 to the casing 41 passes.

(Water detection sensor substrate 32)
The water detection sensor board 32 is a board to which the transmitter 33 and the receiver 34 are communicably connected, and is used to determine the transmission timing (sending timing) and the transmission intensity (electromagnetic wave) of the signal (electromagnetic wave) output from the transmitter 33. The water content (water content) or the presence or absence of water contained in the fuel is calculated from the signal received by the receiver 34. The water detection sensor substrate 32 is a rectangular substrate, and the sides 32a engage with the grooves 35a of the resin holder 35. Further, opposing sides 32b and 32c of the water detection sensor substrate 32 engage with a groove 36a formed in the inner peripheral surface of the metal holder 36. The water detection sensor substrate 32 is arranged inside the metal holder 36 with the side 32a engaged with the groove 35a of the resin holder 35 and the opposing sides 32b and 32c engaged with the groove 36a of the metal holder 36. The slide is inserted.

(Transmitter 33, receiver 34)
The transmitter 33 transmits a terahertz wave (electromagnetic wave) signal (or terahertz wave) to the fuel passing through the flow path 35b of the resin holder 35, and the receiver 34 receives the electromagnetic wave passing through the fuel. Terahertz waves have the characteristic of easily passing through resin and being easily absorbed by water. After passing through the resin holder 35, the terahertz wave transmitted from the transmitter 33 is attenuated by moisture in the fuel passing through the flow path 35b, and is received by the receiver 34. The water detection sensor board 32 calculates the water content in the fuel and the presence or absence of water from the attenuation rate of the electromagnetic waves received by the receiver 34. The transmitter 33 and receiver 34 are fixed to a resin holder 35.

(Resin holder 35)
The resin holder 35 is made of resin and fixes the transmitter 33 and the receiver 34 such that the signal transmission surface of the transmitter 33 faces the signal receiving surface of the receiver 34. The resin holder 35 to which the transmitter 33 and the receiver 34 are fixed is stored inside the metal holder 36.

Here, the resin holder 35 will be described in detail with reference to FIG. 5. As shown in FIG. 5, the resin holder 35 has a groove portion 35a with which the side 32a of the water detection sensor board 32 engages, a flow path 35b through which the fuel passes, a sensor storage chamber 35c in which the transmitter 33 is stored, a sensor storage chamber 35d in which the receiver 34 is stored, a wire passing hole 35e through which a wire that connects the receiver 34 and the water detection sensor board 32 to be able to communicate with each other passes, a ring groove 35f in which an O-ring 37 (see FIG. 4(b)) is attached, and a partition wall 35g that divides the flow path 35b from the sensor storage chambers 35c and 35d. The resin holder 35 is a member in which the above-mentioned groove portion 35a, the flow path 35b, the sensor storage chamber 35c, the sensor storage chamber 35d, the wire passing hole 35e, the ring groove 35f, and the partition wall 35g are unitized or integrally molded.

The width of the groove 35a is approximately the same as the thickness of the water detection sensor board 32. The edge 32a of the water detection sensor board 32 engages with the groove 35a, thereby preventing the resin holder 35 from rotating relative to the water detection sensor board 32. When storing the resin holder 35 inside the metal holder 36, the water detection sensor board 32 engaged with the groove 35a is pushed in, making it possible to install the resin holder 35 at a predetermined position on the inner side of the metal holder 36. At this time, the water detection sensor board 32 slides along the groove 36a formed on the inner surface of the metal holder 36, pushing the resin holder 35 into the inner side of the metal holder 36.

The flow passage 35b is a cross flow passage that intersects at right angles. Note that the flow passages 35b do not have to be perpendicular, as long as they intersect. The flow passage 35b may be a single flow passage with one inlet and one outlet, or may be multiple flow passages with multiple inlets or outlets. The transmitter 33 and the receiver 34 are arranged opposite each other at the position where the flow passages 35b intersect. A partition wall 35g is provided between the flow passage 35b and the transmitter 33 and the receiver 34 so that the transmitter 33 and the receiver 34 do not come into contact with the fuel passing through the flow passage 35b.

The sensor housing chamber 35c houses the transmitter 33 and fixes the position of the transmitter 33. Further, the sensor housing chamber 35d houses the receiver 34 and fixes the position of the receiver 34. Note that the receiver 34 may be housed in the sensor housing chamber 35c, and the transmitter 33 may be housed in the sensor housing chamber 35d.

The wiring passage hole 35e is provided at a position where the flow path 35b is not formed so as not to intersect with the flow path 35b. This wiring passage hole 35e allows the wiring that connects the receiver 34 and the water detection sensor board 32 to pass through. In this embodiment, the transmitter 33 is disposed on the water detection sensor board 32 side, but the transmitter 33 may be disposed on the opposite side of the water detection sensor board 32. In that case, the wiring that connects the transmitter 33 and the water detection sensor board 32 so that they can communicate with each other passes through the wiring passage hole 35e.

An O-ring 37 (see Figs. 4(b) and 6(b)) is fitted into each of the ring grooves 35f. The O-ring 37 seals between the inner circumferential surface of the metal holder 36 and the outer circumferential surface of the resin holder 35, preventing electronic components such as the water detection sensor board 32, transmitter 33, and receiver 34 from becoming immersed or submerged in water.

The partition wall 35g is provided so that the transmitter 33 and the receiver 34 do not come into contact with the fuel. Since the transmitter 33 and the receiver 34 in this embodiment use terahertz waves (electromagnetic waves), the partition wall 35g does not need to be translucent. However, if the transmitter 33 and the receiver 34 use light, the partition wall 35g needs to be translucent.

As shown in FIG. 5(b), the outer diameter of the resin holder 35 decreases toward the tip. The outer diameter r1 of the resin holder 35 on the lid 31 side is larger than the outer diameter r2 on the back side. Since the outer diameter of the resin holder 35 becomes smaller toward the tip, the resin holder 35 can be easily inserted into the metal holder 36.

(Metal holder 36)
Returning to FIG. 3, the metal holder 36 is a member made of metal (conductive material) and has a substantially cylindrical shape. Metal holder 36 houses a water detection sensor assembly therein. A groove portion 36a is formed in the inner circumferential surface of the metal holder 36, with which opposing sides 32b and 32c of the water detection sensor substrate 32 engage. The metal holder 36 has a flange 36c in which a through hole 36b is formed through which a fixing member 39 (see FIG. 6) such as a screw passes. The fixing member 39 passes through the through hole 31a of the lid 31 and the through hole 36b of the metal holder 36, and is tightened into the screw hole 48b of the casing 41 (see FIG. 3(b)).

Furthermore, an opening 36d corresponding to the flow path 35b of the resin holder 35 is formed in the metal holder 36. The flow path 35b of the resin holder 35 is a cross flow path, and since fuel inlets and outlets are formed at four locations in total, openings 36d are also formed at four locations. As shown in FIG. 6(b), the opening area of the opening 36d of the metal holder 36 is larger than the opening area of the inlet and outlet of the flow path 35b of the resin holder 35. As a result, even if a slight positional deviation occurs between the center of the opening 36d of the metal holder 36 and the center of the inlet and outlet of the flow path 35b of the resin holder 35, the inlet and outlet of the flow path 35b of the resin holder 35 The outlet can be prevented from being blocked by the metal holder 36.

As shown in FIG. 4B, the inner diameter of the inner peripheral surface of the metal holder 36 becomes smaller toward the tip. The inner diameter R1 of the inner peripheral surface of the metal holder 36 on the lid 31 side is larger than the inner diameter R2 on the rear side. The inner diameter R1 of the inner peripheral surface of the metal holder 36 on the lid 31 side and the outer diameter r1 of the resin holder 35 on the lid 31 side are approximately the same, and the inner diameter R2 of the inner peripheral surface of the metal holder 36 on the rear side and the outer diameter r2 of the resin holder 35 on the rear side are approximately the same. In this way, by designing the outer diameters R1 and R2 of the resin holder 35 and the inner diameters r1 and r2 of the metal holder 36 to be approximately the same and attaching an O-ring 37 to the outer peripheral surface of the metal holder 36, it is possible to prevent electronic components such as the water detection sensor board 32, the transmitter 33, and the receiver 34 stored inside the metal holder 36 from being immersed or submerged in water.

Further, as shown in FIG. 4(b), an O-ring accommodating portion 36e for accommodating an O-ring 38 is formed on the lid 31 side of the metal holder 36. The O-ring 38 is disposed between the metal holder 36 and the casing 41 and prevents immersion or water from entering between the metal holder 36 and the casing 41.

(Effects of this embodiment)
A resin in which a sensor housing chamber 35c in which the transmitter 33 is housed, a sensor housing chamber 35d in which the receiver 34 is housed, and a flow path 35b formed between the sensor housing chamber 35c and the sensor housing chamber 35d are unitized. By using the holder 35, the transmitter 33 and the receiver 34 can be attached with the flow path 35b interposed therebetween while the distance between the transmitter 33 and the receiver 34 is accurately adjusted. Thereby, it is possible to easily adjust the distance between the transmitter 33 and the receiver 34, which is necessary for accurately detecting water in the fuel. As a result, it becomes possible to accurately detect water in fuel.

By forming an opening 36d in the metal holder 36 that corresponds to the flow path 35b in the resin holder 35, fuel can be made to flow into or out of the flow path 35b of the resin holder 35 via the opening 36d in the metal holder 36, even if the resin holder 35 and the water detection sensor board 32 are covered with the metal holder 36 for immersion, submersion, or electromagnetic shielding.

Since the metal holder 36 is made of a conductive material, the electromagnetic shielding effect protects electronic devices such as the transmitter 33, the receiver 34, and the water detection sensor substrate 32 stored inside the metal holder 36. The effects of radio waves, electromagnetic waves, and electrostatic fields can be reduced.

A groove 35a is formed in the resin holder 35 to which the side 32a of the water detection sensor substrate 32 engages, and a groove 36a is formed in the metal holder 36 to be engaged by the opposing sides 32b and 32c of the water detection sensor substrate 32. This allows the resin holder 35 to be slid into the metal holder 36 while being pushed in by the water detection sensor substrate 32 . Thereby, the resin holder 35 can be easily moved to a predetermined position on the inner side of the metal holder 36. Further, at this time, the rotation of the water detection sensor substrate 32 with respect to the metal holder 36 is regulated by engaging the water detection sensor substrate 32 with the groove 36a of the metal holder 36, and the groove 35a of the resin holder 35 By engaging the water detection sensor substrate 32, rotation of the resin holder 35 with respect to the water detection sensor substrate 32 is restricted. As a result, simply by sliding the resin holder 35 into the metal holder 36 using the water detection sensor substrate 32, alignment between the channel 35b of the resin holder 35 and the opening 36d of the metal holder 36 is achieved. It becomes possible.

By forming a plurality of channels 35b through which the fuel passes in the resin holder 35, and providing a sensor accommodation chamber 35c and a sensor accommodation chamber 35d across the intersection where the plurality of channels 35b intersect, the plurality of channels 35b are formed. Since water in the fuel flowing inside can be detected, water detection accuracy is improved.

By providing the resin holder 35 with a partition wall 35g that partitions the sensor storage chamber 35c and the flow path 35b, and a partition wall 35g that partitions the sensor storage chamber 35c and the flow path 35b, the transmitter 33 and the receiver 34 can be connected. Since the transmitter 33 and the receiver 34 do not get wet, it is possible to prevent deterioration of the transmitter 33 and the receiver 34 due to contact with the liquid.

By configuring the water detection sensor unit 30 to be detachably attached to the casing 41 of the pump unit 40, maintainability of the water detection sensor unit 30 is improved.

Furthermore, since the resin holder 35 becomes thinner toward the back, there is less resistance when moving the resin holder 35 to the back inside the metal holder 36, and workability is improved.

Although the present invention has been described above along with the embodiments, the above embodiments are merely examples of implementation of the present invention, and the technical scope of the present invention should not be construed as limited by these embodiments. It is something that should not happen. That is, the present invention can be implemented in various forms without departing from its technical idea or main features.

In the above embodiment, the transmitter 33 and the receiver 34 use terahertz waves (electromagnetic waves), but as long as they can detect the moisture content or the presence or absence of water in the fuel, they are not limited to those that use terahertz waves (electromagnetic waves). For example, the transmitter 33 and the receiver 34 may use light or sound.

Further, in the above-described embodiment, the water detection sensor unit 30 is installed in the sensor unit storage chamber 48 between the air separation chamber 47 and the filter chamber 49, but the installation position of the water detection sensor unit 30 is in the sensor unit storage chamber. It is not limited to 48. For example, the water detection sensor unit 30 may be installed in the strainer installation chamber 44, the check valve installation chamber 45, and the filter chamber 49 on the fuel supply path inside the pump unit 40, or the water detection sensor unit 30 may be installed in the fuel supply path outside the pump unit 40. It may be installed above.

In the above-described embodiment, the resin holder 35 is disposed inside the metal holder 36 which is long in the insertion direction of the resin holder 35, so the work of attaching the resin holder 35 is laborious. Therefore, as shown in FIG. 7, a modified metal holder 136 is configured by being divided into two members 136a and 136b. A thread 136c is formed on the outer peripheral surface of the member 136a, and a thread groove 136d is formed on the inner peripheral surface of the member 136b. Note that a thread groove may be formed on the outer circumferential surface of the member 136a and a thread thread may be formed on the inner circumferential surface of the member 136b, or a thread or thread groove may be formed on the inner circumferential surface of the member 136a and the thread groove may be formed on the inner circumferential surface of the member 136b. A thread groove or thread may be formed on the outer peripheral surface. First, the resin holder 35 to which the transmitter 33 and receiver 34 are attached is housed inside the member 136b on the distal end side. Since the length of the member 136b in the insertion direction of the resin holder 35 is shorter than that of the metal holder 36, the work of attaching the resin holder 35 is easy. Then, the member 136a and the member 136b are fastened by rotating and tightening the thread 136c into the thread groove 136d. Further, an O-ring 137 is provided between the two members 136a and 136b to prevent water from entering the case.

(Water detection sensor unit 230)
Next, details of the water detection sensor unit 230 of the second embodiment will be described with reference to FIGS. 8 to 11. Descriptions similar to those in Example 1 will be omitted as appropriate. As shown in FIG. 8, the water detection sensor unit 230 of the second embodiment includes a lid 231, a water detection sensor substrate 232, a transmitter 233, a receiver 234, a resin holder 235, a metal holder 236, and a water detection sensor substrate. It has a fixing plate 237 (hereinafter abbreviated as fixing plate 237) and a lid 238. Inside the cylindrical metal holder 236, a water detection sensor substrate 232, a transmitter 233, a receiver 234, a resin holder 235, and a fixing plate 237 (hereinafter referred to as water detection sensor substrate 232, transmitter 233, receiver 234) are installed. , the resin holder 235, and the fixing plate 237 (referred to as a "water detection sensor assembly") are housed therein. Furthermore, hereinafter, the transmitter 233 and receiver 234 will be referred to as "sensors". The metal holder 236 is open on both sides. The water detection sensor substrate 232 and the fixing plate 237 are inserted into the metal holder 236 through the insertion opening 236a on the lid 231 side. Further, the transmitter 233, the receiver 234, and the resin holder 235 are inserted into the metal holder 236 through the insertion port 236b on the casing 41 side. Then, the lid 231 is placed so as to close the insertion opening 236a of the metal holder 236, and the lid 238 is attached so as to close the insertion opening 236b of the metal holder 236. The water detection sensor assembly, lid 231, and lid 238 integrally configured in this manner are fixed to the casing 41 (see FIG. 8(a)).

(Lid 231)
As shown in FIG. 8, the lid 231 closes an insertion opening 236a for introducing the water detection sensor substrate 232 and the fixing plate 237 into the metal holder 236. The lid 231 is fixed to the metal holder 236 and the casing 41. The lid 231 has a through hole 231a through which a fixing member 240 such as a screw for fixing the lid 231 to the metal holder 236 passes, and a fixing member such as a screw to fix the lid 231 and the metal holder 236 to the casing 41. It has a flange portion 231c in which a through hole 231b through which the 241 passes is formed.

(Water detection sensor substrate 232)
The water detection sensor board 232 is a board to which the transmitter 233 and the receiver 234 are communicatively connected, and controls the transmission timing and transmission strength of the signal output from the transmitter 233, and calculates the water content (water content rate) or the presence or absence of water in the fuel from the signal received by the receiver 234. The water detection sensor board 232 is a rectangular board, but its shape is not limited to a rectangle. The water detection sensor board 232 may be a laminated board in which multiple boards are laminated, or may be a single-layer board.

The water detection sensor board 232 is fixed to a fixing plate 237. The water detection sensor board 232 fixed to the fixing plate 237 is then fixed to a metal holder 236. As shown in FIG. 8(b), the water detection sensor board 232 has a plurality of through holes 232a formed therein through which fixing members 242 (see FIG. 9), such as screws, pass to fix the water detection sensor board 232 to the fixing plate 237.

(Fixed plate 237)
The fixing plate 237 is a member for fixing the water detection sensor board 232 inside the metal holder 236. The fixing plate 237 is an example of a fastening member for fastening the water detection sensor board 232 to the mounting base 236f of the metal holder 236. As shown in FIG. 8B, the fixing plate 237 has a screw hole 237a formed at a position corresponding to the through hole 232a described above. The water detection sensor board 232 can be fixed to the fixing plate 237 by fastening a fixing member 242 (see FIG. 9) that has passed through the through hole 232a of the water detection sensor board 232 to the screw hole 237a. The fixing plate 237 also has two through holes 237b that open in the insertion direction of the water detection sensor board 232 (X direction in the figure). A fixing member 243 (see FIG. 9) such as a screw for fixing the fixing plate 237 to the metal holder 236 passes through the through hole 237b.

(Transmitter 233, receiver 234)
The transmitter 233 transmits a terahertz wave (electromagnetic wave) signal to the fuel passing through the flow path 235b of the resin holder 235, and the receiver 234 receives the electromagnetic wave passing through the fuel. Terahertz waves have the characteristic of easily passing through resin and being easily absorbed by water. After passing through the resin holder 235, the terahertz wave transmitted from the transmitter 233 is attenuated by moisture in the fuel passing through the flow path 235b, and is received by the receiver 234. The water detection sensor board 232 calculates the water content in the fuel and the presence or absence of water from the attenuation rate of the electromagnetic waves received by the receiver 234. The transmitter 233 and receiver 234 are fixed to a resin holder 235 with adhesive.

(Resin holder 235)
As shown in Figures 8(b) and 9, the resin holder 235 has upper and lower protrusions 235a that engage with the metal holder 236, a flow path 235b through which fuel passes, a sensor accommodating chamber 235c in which the transmitter 233 is accommodated, a sensor accommodating chamber 235d in which the receiver 234 is accommodated, a wiring passing hole 235e through which wiring that communicatively connects the receiver 234 and the water detection sensor board 232 passes, a ring groove 235f in which an O-ring 251 (see Figure 9) is fitted, and a partition wall 235g that separates the flow path 235b from the sensor accommodating chambers (sensor accommodating sections) 235c and 235d. Resin holder 235 is a member in which protrusion 235a, flow path 235b, sensor accommodating chamber 235c, sensor accommodating chamber 235d, wire passing hole 235e, ring groove 235f, and partition wall 235g are unitized or integrally molded.

As shown in FIG. 10, the protrusion 235a engages with the mounting base 236f and the restricting portion 236h inside the metal holder 236, thereby preventing the resin holder 235 from rotating relative to the metal holder 236 and the water detection sensor board 232. When storing the resin holder 235 inside the metal holder 236, the lid 238 is screwed into the threaded portion 236k (see FIG. 9 and FIG. 11) of the metal holder 236 and the resin holder 235 is pushed in, thereby making it possible to install the resin holder 235 at a predetermined position at the back of the interior of the metal holder 236.

(Metal holder 236)
As shown in FIGS. 8, 10, and 11, the metal holder 236 is a member made of metal (conductive material) and has a substantially cylindrical shape. Metal holder 236 houses a water detection sensor assembly therein. The metal holder 236 has a screw hole 236c into which a fixing member 240 such as a screw for fixing the lid 231 to the metal holder 236 is tightened, and a screw hole 236c for fixing the lid 231 and the metal holder 236 to the casing 41. It has a flange 236e in which a through hole 236d through which the fixing member 241 passes is formed. The lid 231 is fixed to the metal holder 236 by tightening the fixing member 240 that has passed through the through hole 231a of the lid 231 into the screw hole 236c. In addition, by tightening the fixing member 241 that has passed through the through hole 231b of the lid 231 and the through hole 236d of the metal holder 236 into the screw hole 48b of the casing 41 (see FIG. 8(b)), the lid 231 and the metal holder can be fixed. 236 is fixed to the casing 41.

In addition, the metal holder 236 of the second embodiment is provided with a mounting base 236f for mounting the water detection sensor substrate 232 fixed to the fixing plate 237. The mounting base 236f is formed with two screw holes 236g opening in the insertion direction (X direction in the figure) of the water detection sensor substrate 232, and the fixing member 243 such as a screw passing through the through hole 237b of the fixing plate 237 is fastened to the screw hole 236g. As shown in FIG. 10, the mounting bases 236f are provided at a predetermined interval in the Y direction in the figure. In addition, the metal holder 236 is provided with a regulating portion 236h at a predetermined interval in the Y direction in the figure so as to correspond to the above-mentioned mounting base 236f. The upper and lower protrusions 235a of the resin holder 235 are arranged in the space between the two regulating portions 236h and the space between the two mounting bases 236f, respectively. This prevents the resin holder 235 from rotating circumferentially inside the metal holder 236. The position at which the resin holder 235 is positioned by the above structure is a position at which the flow path 235b of the resin holder 235 and the opening 236j of the metal holder 236 are open to each other.

As shown in FIG. 11, the inner peripheral surface of the metal holder 236 is formed with a chamfer 236i. This prevents the O-ring 251 of the resin holder 235 from being damaged by the edge of the opening 236j corresponding to the flow path 235b of the resin holder 235 when the resin holder 235 is inserted into the metal holder 236.

Furthermore, a threaded portion 236k is formed on the inner peripheral surface of the metal holder 236. A threaded portion is also formed on the outer peripheral surface of the lid 238, and by screwing the lid 238 into the metal holder 236, the resin holder 235 can be pushed in and the lid 238 can be fixed to the metal holder 236. .

Note that as shown in FIG. 9, an O-ring 252 may be placed between the lid 231 and the metal holder 236, or an O-ring 253 may be placed between the metal holder 236 and the casing 41. You can. Further, an O-ring 254 may be arranged between the inner peripheral surface of the metal holder 236 and the outer peripheral surface of the lid 238.

The water detection sensor board 232 can be easily positioned by screwing it to the fixing plate 237, and then fixing the fixing plate 237 to the mounting base 236f inside the metal holder 236. In addition, fixing it with screws (fixing members 243) also serves as a measure against vibration when the pump is operating, so there is no need to apply vibration measures such as resin molding to the water detection sensor board 232, and the risk of cracks due to differences in the linear expansion coefficient between the molding material and each member can be avoided.

The groove portion 36a of the metal holder 36 of Example 1 and the mounting table 236f of the metal holder 236 of Example 2, which have a structure for holding the water detection sensor substrate 32 or 232, are examples of the holding portion of the present invention. .

Although the present embodiment has been described as detecting moisture in liquid fuel such as gasoline or light oil, the type of liquid fuel is not limited to this, and may be a hydrophobic liquid fuel.

1: Oil supply device, 2: Oil supply device body, 11: Pump, 12: Pump motor, 13: Flow meter, 14: Flow rate transmitter, 15: Internal piping, 16: Oil supply hose, 17: Oil supply nozzle, 18: Nozzle storage Part, 19: Nozzle switch, 20: Display, 21: Underground piping, 22: Underground tank, 23: Control device, 30: Water detection sensor unit, 31: Lid, 31a: Through hole, 31b: Flange, 32: Water detection sensor substrate, 32a to 32c: side, 33: transmitter (transmitter), 34: receiver (receiver), 35: resin holder (first holder), 35a: groove (holding part), 35b : Channel, 35c, 35d: Sensor housing chamber (sensor housing part), 35e: Wiring passage hole, 35f: Ring groove, 35g: Partition wall, 36, 136: Metal holder (second holder), 36a: Groove (holding part), 36b: through hole, 36c: collar, 36d: opening, 36e: O-ring accommodating part, 37, 38: O-ring, 39: fixing member, 40: pump unit, 41: casing, 136a, 136b: Member, 230: Water detection sensor unit, 231: Lid, 232: Water detection sensor substrate, 233: Transmitter (transmitter), 234: Receiver (receiver), 235: Resin holder, 235g: Partition wall , 236: metal holder, 236a: insertion port, 236f: mounting table (holding part), 236g: screw hole, 236j: opening, 237: water detection sensor substrate fixing plate (fastening member), 237b: through hole, 238: Lid

Claims (9)

A water detection sensor unit that detects water in fuel supplied to a fuel supply target,
a transmitter that transmits electromagnetic waves;
a receiver that receives the electromagnetic waves transmitted from the transmitter;
A first sensor housing part in which the transmitter is housed, a second sensor housing part in which the receiver is housed, and formed between the first sensor housing part and the second sensor housing part. a first holder having a flow path;
A water detection sensor unit comprising: Each of the transmitter and the receiver further includes a second holder for storing the first holder accommodated in the first sensor accommodating portion and the second sensor accommodating portion,
2. The water detection sensor unit according to claim 1, wherein the second holder has an opening formed therein for allowing the fuel to flow into the flow passage formed in the first holder or for allowing the fuel to flow out of the flow passage. The water detection sensor unit according to claim 2 , wherein the second holder is made of a conductive material. further comprising a board communicably connected to the transmitter and the receiver,
The water detection sensor unit according to claim 2, wherein the second holder is provided with a holding part that holds the substrate inside. The water detection sensor unit according to claim 4 , further comprising a fastening member for fastening the substrate to the holding portion of the second holder. The second holder is provided with an insertion opening into which the board is inserted,
The water detection sensor according to claim 5, wherein the holding portion and the fastening member are provided with a hole that opens in the insertion direction of the substrate, and screwing can be performed from the insertion opening to the hole. unit. 2. The water detection sensor unit according to claim 1, wherein the first holder is formed with a plurality of flow paths through which the fuel passes, and the first sensor housing and the second sensor housing are provided on either side of an intersection where the plurality of flow paths intersect. The first holder includes a first partition wall that partitions the first sensor accommodating part and the flow path, and a second partition wall that partitions the second sensor accommodation part and the flow path. The water detection sensor unit according to claim 1, characterized in that it has: a pump provided on a fuel supply path that supplies fuel from a tank that stores fuel to a fuel supply target;
The water detection sensor unit according to any one of claims 1 to 8,
The fuel supply device according to claim 1, wherein the water detection sensor unit is detachably attached to a casing of the pump.