Sensor module

Abstract

To provide a sensor module that protects a power supply unit and a communication unit against an external factor such as water, a pressure and the like.SOLUTION: A sensor module 3 comprises: an electric type sensor 3d; a power supply unit 3b that converts light received from an optical fiber 4 into electricity; a communication unit 3c that converts an electric signal received from the electric type sensor 3d into an optical signal; a metal unit case 11 that is formed into a cylinder having both ends opened, and accommodates the power supply unit 3b and communication unit 3c; a first encapsulation part that encapsulates a sensor-side opening end part 11a which is one end part of the unit case 11; and a second encapsulation part that encapsulates an optical fiber-side opening end part 11b which is other end part of the unit case 11.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sensor module used for measurement using an electric sensor.

Background Art

[0002] In recent years, the parameters that can be measured by optical sensors using optical fibers have been increasing, but there are also many parameters that can only be measured by electric sensors. In particular, the measurement of parameters of groundwater in a borehole or underground facilities is currently mainly carried out by electric sensors. However, electric sensors have problems such as limitations in transmission distance, corrosion of electric wires, effects of lightning strikes and electrical noise, and explosion protection. For this reason, a monitoring system that supplies power to an electric sensor using an optical fiber and communicates with the electric sensor using an optical fiber has come to be considered (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described monitoring system, a measuring device installed on the ground and a sensor module arranged at a measurement point are connected by an optical cable. The sensor module is equipped with an electric sensor, a power supply unit, and a communication unit. The power supply unit converts the light received from the optical cable into electricity and supplies power to the electric sensor. The communication unit converts the output of the electric sensor into an optical signal and transmits the optical signal to the measuring device in order to monitor the output of the electric sensor with the measuring device.

[0005] Although commercially available general-purpose products can be used for the electric sensor, since the power supply unit and the communication unit are not commercially available general-purpose products such as electric sensors, they are extremely expensive and it is not easy to obtain substitutes. Therefore, in the sensor module, it is important to protect the power supply unit and the communication unit from external factors such as water and pressure. In particular, in the measurement of groundwater parameters in a borehole or underground facilities, since the sensor module is placed under the pressure of water, the protection of the power supply unit and the communication unit against external factors such as water and pressure becomes more important. However, a sensor module that protects the power supply unit and the communication unit against such external factors has not yet been disclosed.

[0006] Therefore, an object of the present invention is to provide a sensor module capable of protecting a power supply unit and a communication unit against external factors such as water and pressure.

Means for Solving the Problems

[0007] The sensor module according to the present invention includes an electric sensor, a power supply unit that converts the light received from the optical fiber into electricity, a communication unit that converts the electrical signal received from the electric sensor into an optical signal, a metal unit case formed in a cylindrical shape with both ends open to accommodate the power supply unit and the communication unit, a first sealing portion that seals the sensor-side opening end portion which is one end portion of the unit case, and a second sealing portion that seals the optical fiber-side opening end portion which is the other end portion of the unit case.

[0008] In this sensor module, since the unit case that houses the power supply unit and the communication unit is made of metal formed in a cylindrical shape, it can have high pressure resistance. Further, since the unit case is formed in a cylindrical shape with both ends open, the unit case can be easily manufactured. And since the sensor-side opening end portion and the optical fiber-side opening end portion of the unit case are sealed by the first sealing portion and the second sealing portion, it can have high water resistance. For this reason, the power supply unit and the communication unit can be protected against external factors such as water and pressure.

[0009] The unit case may be made of stainless steel. In this sensor module, since the unit case is made of stainless steel, it can have low cost and high pressure resistance and corrosion resistance. Thereby, the power supply unit and the communication unit can be protected against external factors such as water and pressure over a long period of time.

[0010] It may further include a metal sensor case for housing an electric sensor, the sensor case having a first insertion end portion inserted into the sensor-side opening end portion to form an opening, and the first sealing portion including the sensor case, a sealing connector that seals the opening and electrically connects a first electric wire disposed in the unit case and a second electric wire disposed in the sensor case, and a first O-ring disposed between the sensor-side opening end portion and the first insertion end portion to seal between the sensor-side opening end portion and the first insertion end portion. In this sensor module, since the sensor case for housing the electric sensor is made of metal, the electric sensor can be appropriately protected. And the sensor-side opening end portion of the unit case is sealed by the sensor case having a first insertion end portion inserted into the sensor-side opening end portion, a sealing connector that seals the opening of the first insertion end portion, and a first O-ring disposed between the sensor-side opening end portion and the first insertion end portion. Therefore, while electrically connecting the first electric wire disposed in the unit case and the second electric wire disposed in the sensor case, the sensor-side opening end portion of the unit case can be sealed. Also, since both the sensor-side opening end portion of the unit case sandwiching the first O-ring and the first insertion end portion of the sensor case are made of metal, the space between the first O-ring and the sensor-side opening end portion of the unit case and the first insertion end portion of the sensor case can be appropriately sealed.

[0011] Furthermore, it further includes a columnar optical fiber introduction member having an introduction hole for airtightly introducing an optical fiber. The optical fiber introduction member has a second insertion end portion inserted into the optical fiber side opening end portion. The second sealing portion may include an optical fiber introduction member and a second O-ring disposed between the optical fiber side opening end portion and the second insertion end portion for sealing between the optical fiber side opening end portion and the second insertion end portion. In this sensor module, the optical fiber side opening end portion of the unit case is sealed by an optical fiber introduction member having a second insertion end portion inserted into the optical fiber side opening end portion and a second O-ring disposed between the optical fiber side opening end portion and the second insertion end portion. Therefore, while introducing the optical fiber, the optical fiber side opening end portion of the unit case can be sealed.

[0012] It may further include a fixing mechanism for fixing the optical fiber introduction member to the unit case. In this sensor module, since the optical fiber introduction member is fixed to the unit case by the fixing mechanism, when the sensor module is placed under a pressure water, it is possible to suppress the optical fiber introduction member from being pushed into the unit case by the external pressure.

[0013] The unit case further includes a nut for fixing the optical fiber introduction member, the optical fiber side opening end portion has a first bulging portion protruding radially inward of the unit case, the optical fiber introduction member further has a second bulging portion formed on the outer peripheral surface of the second insertion end portion and abutting against the first bulging portion from the sensor side opening end portion side, an extending portion protruding from the unit case, and a male screw formed on the outer peripheral surface of the extending portion. The fixing mechanism may include the first bulging portion, the second bulging portion, and a nut formed with a female screw screwed onto the male screw of the extending portion. In this sensor module, the optical fiber introduction member has an extending portion protruding from the unit case, and the female screw formed on the nut is screwed onto the male screw formed on the extending portion. Therefore, by tightening the nut, the nut abuts against the end surface of the unit case, and the second bulging portion of the optical fiber introduction member abuts against the first bulging portion of the unit case from the sensor side opening end portion side. As a result, the first bulging portion of the unit case is sandwiched between the nut and the second bulging portion of the optical fiber introduction member, so that the optical fiber introduction member can be appropriately fixed to the unit case.

[0014] The sensor module further includes a unit mounting member that mounts a power supply unit and a communication unit and is fixed to the sensor case and the optical fiber introduction member. The optical fiber introduction member may be configured to be insertable and removable from the unit case from the sensor side opening end portion side. In this sensor module, the unit mounting member that mounts the power supply unit and the communication unit is fixed to the sensor case and the optical fiber introduction member, and the optical fiber introduction member is insertable and removable from the unit case from the sensor side opening end portion side. Therefore, by inserting and removing the optical fiber introduction member with respect to the unit case from the sensor side opening end portion side, the unit mounting member on which the power supply unit and the communication unit are mounted, and the sensor case can also be integrally inserted and removed with respect to the unit case.

[0015] The maximum outer diameter of the extending portion is equal to or less than the minimum inner diameter of the unit case, and the maximum outer diameter of the optical fiber introduction member may be equal to or less than the minimum inner diameter of the portion on the sensor-side opening end side of the unit case than the first bulging portion. In this sensor module, since the maximum outer diameter of the extending portion is equal to or less than the minimum inner diameter of the unit case and the maximum outer diameter of the optical fiber introduction member is equal to or less than the minimum inner diameter of the portion on the sensor-side opening end side of the unit case than the first bulging portion, the optical fiber introduction member can be inserted into and removed from the unit case from the sensor-side opening end side.

Effect of the Invention

[0016] According to the present invention, the power supply unit and the communication unit can be protected against external factors such as water and pressure.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0019] FIG. 1 is a block configuration diagram of a monitoring system including a sensor module according to an embodiment. The monitoring system 1 shown in FIG. 1 is a system for measuring various parameters at a measurement point. The measurement point is not particularly limited, but for example, it is groundwater in a boring hole or underground facilities. The monitoring system 1 includes a measurement device 2 installed on the ground or the like, a sensor module 3 disposed at the measurement point, and one or a plurality of optical fibers 4 connecting the measurement device 2 and the sensor module 3.

[0020] The measurement device 2 is connected to a control device (not shown) such as a personal computer and is a device for performing measurement by the sensor module 3. The measurement device 2 has a light source unit 2a and a communication unit 2b. The light source unit 2a irradiates light on the optical fiber 4 in order to perform optical power supply to the sensor module 3. For example, the number of optical fibers 4 corresponding to the amount of electric power for performing optical power supply is connected to the light source unit 2a. The communication unit 2b converts an electric signal received from the control device into an optical signal and transmits it to the optical fiber 4, and also converts an optical signal received from the optical fiber 4 into an electric signal and transmits it to the control device. For example, a total of two optical fibers 4, namely, an optical fiber 4 for transmitting an optical signal from the measurement device 2 to the communication unit 2b and an optical fiber 4 for transmitting an optical signal from the communication unit 2b to the measurement device 2, are connected to the communication unit 2b.

[0021] The sensor module 3 is a module disposed at the measurement point and measures various parameters at the measurement point. The sensor module 3 has a sensor unit 3a, a power supply unit 3b, and a communication unit 3c.

[0022] The sensor unit 3a includes one or more electric sensors 3d that measure various parameters, and a profiler 3e that profiles the outputs of the one or more electric sensors 3d and outputs an electric signal. The one or more electric sensors 3d are sensors that operate when powered and output the measured information as an electric signal. The one or more electric sensors 3d are not particularly limited, and examples include a pressure sensor that measures water pressure, a pH sensor that measures hydrogen ion concentration, an ORP sensor that measures oxidation-reduction potential, an EC sensor that measures electrical conductivity, a TSS sensor that measures turbidity, a DO sensor that measures dissolved oxygen, a temperature sensor that measures water temperature, a soil moisture meter that measures soil moisture content, a neutron moisture meter that measures moisture content, and the like.

[0023] The power supply unit 3b converts the light received from the optical fiber 4 into electricity and supplies power to the sensor unit 3a and the communication unit 3c. The communication unit 3c receives power from the power supply unit 3b, converts the optical signal received from the optical fiber 4 into an electric signal and transmits it to the sensor unit 3a, and converts the electric signal received from the sensor unit 3a into an optical signal and transmits it to the optical fiber 4.

[0024] Thus, in the monitoring system 1, optical power is supplied from the measuring device 2 to the sensor module 3 via the optical fiber 4, and optical communication is performed between the measuring device 2 and the sensor module 3 via the optical fiber 4.

[0025] FIG. 2 is a cross-sectional view of the sensor module according to the embodiment. As shown in FIG. 2, the sensor module 3 according to the present embodiment includes, in addition to the sensor unit 3a, the power supply unit 3b, and the communication unit 3c described above, a unit case 11, a sensor case 12, an optical fiber introduction member 13, a nut 14, and a unit mounting member 15.

[0026] FIG. 3 is an enlarged cross-sectional view of the connection portion between the unit case and the sensor case. FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3. FIG. 5 is an enlarged cross-sectional view of the connection portion between the unit case and the optical fiber introduction member. FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. 5. As shown in FIGS. 2 to 6, the unit case 11 is a case that houses the power supply unit 3b and the communication unit 3c. The unit case 11 is formed in a cylindrical shape with both ends open. Inside the unit case 11, an accommodation space S for housing the power supply unit 3b and the communication unit 3c is formed. The unit case 11 is made of metal. From the viewpoint of low cost and high pressure resistance and corrosion resistance, the unit case 11 can be made of stainless steel.

[0027] One end of the unit case 11 is referred to as the sensor-side opening end 11a, and the other end of the unit case 11 is referred to as the optical fiber-side opening end 11b. The sensor-side opening end 11a is the opening end on the sensor case 12 side in the extending direction D of the unit case 11. The optical fiber-side opening end 11b is the opening end on the optical fiber introduction member 13 side in the extending direction D of the unit case 11. The central portion of the unit case 11 excluding the sensor-side opening end 11a and the optical fiber-side opening end 11b is referred to as the case central portion 11c. The power supply unit 3b and the communication unit 3c are housed in the case central portion 11c.

[0028] The outer diameter of the unit case 11 is the same over the entire length in the extending direction D of the unit case 11. The inner diameter of the case central portion 11c is the same over the entire length in the extending direction D of the unit case 11. The inner diameter of the sensor-side opening end 11a is equal to or greater than the inner diameter of the case central portion 11c.

[0029] A female screw 11d is formed on the inner peripheral surface of the sensor-side opening end 11a. The female screw 11d is a thread groove formed on the inner peripheral surface of the sensor-side opening end 11a.

[0030] On the inner peripheral surface of the optical fiber side opening end portion 11b, a first bulging portion 11e protruding radially inward of the unit case 11 is formed. The first bulging portion 11e is a portion protruding inward in the radial direction of the unit case 11 (toward the accommodation space S). The first bulging portion 11e is formed at the end of the sensor side opening end portion 11a, and the minimum inner diameter of the first bulging portion 11e is the minimum inner diameter of the unit case 11.

[0031] The minimum inner diameter of the portion on the sensor side opening end portion 11a side of the optical fiber side opening end portion 11b, which is closer to the sensor side opening end portion 11a than the first bulging portion 11e, is equal to or greater than the minimum inner diameter of the case central portion 11c. Note that the minimum inner diameter is the smallest inner diameter. For example, when the inner diameter varies in the extending direction D of the unit case 11, it refers to the smallest inner diameter. Also, the maximum outer diameter is the largest outer diameter. For example, when the outer diameter varies in the extending direction D of the unit case 11, it refers to the largest outer diameter.

[0032] As shown in FIGS. 2 to 4, the sensor case 12 is a case that houses the sensor portion 3a. That is, the sensor case 12 houses the profiler 3e and one or a plurality of electric sensors 3d. The material of the sensor case 12 is not particularly limited, but from the viewpoint of protecting the sensor portion 3a, the sensor case 12 can be made of metal. In this case, the sensor case 12 can be made of stainless steel from the viewpoints of low cost, high pressure resistance, and corrosion resistance.

[0033] The sensor case 12 is formed in a cylindrical shape. The sensor case 12 has a first insertion end portion 12b that is inserted into the sensor side opening end portion 11a and an opening 12a is formed. That is, the portion of the sensor case 12 that is inserted into the sensor side opening end portion 11a becomes the first insertion end portion 12b. A sealing connector 16 for sealing the opening 12a is fixed to the first insertion end portion 12b.

[0034] The sealing connector 16 electrically connects a plurality of first electric wires W1 arranged in the unit case 11 and a plurality of second electric wires W2 arranged in the sensor case 12 while hermetically holding the opening 12a. That is, in the unit case 11, there are arranged a first electric wire W1 connected to the power supply unit 3b to supply power to the sensor unit 3a, and one or a plurality of first electric wires W1 connected to the communication unit 3c to perform communication by an electric signal with the sensor unit 3a. In the sensor case 12, there are arranged a second electric wire W2 connected to the sensor unit 3a to supply power to the sensor unit 3a, and one or a plurality of second electric wires W2 connected to the sensor unit 3a to perform communication by an electric signal with the sensor unit 3a. And the sealing connector 16 has a plurality of electric wires 16a connected to the plurality of first electric wires W1 and the plurality of second electric wires W2, and a sealing portion 16b such as glass that hermetically holds the plurality of electric wires 16a and seals the opening 12a. Also, an O-ring 17 that seals between the sealing connector 16 and the first insertion end portion 12b is arranged between the sealing connector 16 and the first insertion end portion 12b. As the sealing connector 16, for example, a hermetic connector can be used.

[0035] On the outer peripheral surface of the first insertion end portion 12b, a male screw 12c and a recess 12d are formed. The male screw 12c is a thread groove formed on the outer peripheral surface of the first insertion end portion 12b so as to be screwed into the female screw 11d of the sensor-side opening end portion 11a. The recess 12d is an annular groove, and an O-ring 18 (first O-ring) is inserted into the recess 12d. The O-ring 18 is a sealing member arranged between the sensor-side opening end portion 11a and the first insertion end portion 12b to seal between the sensor-side opening end portion 11a and the first insertion end portion 12b.

[0036] On the end surface of the first insertion end portion 12b, a screw hole 12e is formed. The screw hole 12e is a bottomed hole in which a thread groove of a female screw is formed. A screw 21 described later is screwed into the screw hole 12e.

[0037] The first insertion end portion 12b is shaped to be insertable and removable with respect to the sensor-side opening end portion 11a. Specifically, the first insertion end portion 12b is locked to the sensor-side opening end portion 11a only at the male screw 12c in the extending direction D of the unit case 11. Also, the maximum outer diameter of the first insertion end portion 12b is equal to or less than the minimum inner diameter of the portion of the sensor-side opening end portion 11a on the side opposite to the optical fiber-side opening end portion 11b with respect to the female screw 11d. For this reason, by releasing the screwing of the male screw 12c with respect to the female screw 11d, the first insertion end portion 12b can be inserted and removed with respect to the sensor-side opening end portion 11a.

[0038] And the sensor-side opening end portion 11a is sealed by the sensor case 12, the sealing connector 16, and the O-ring 18. For this reason, the sensor case 12, the sealing connector 16, and the O-ring 18 function as a first sealing portion for sealing the sensor-side opening end portion 11a.

[0039] As shown in FIGS. 2, 3, 5, and 6, the optical fiber introduction member 13 is a lid member in which an introduction hole 13a for hermetically introducing one or a plurality of optical fibers 4 is formed. One or a plurality of optical fibers 4 are hermetically inserted into the introduction hole 13a. The material of the optical fiber introduction member 13 is not particularly limited, but from the viewpoints of low cost and high pressure resistance and corrosion resistance, it can be made of stainless steel. Note that a tube (not shown) made of high-density polyethylene (HDPE) is connected to the introduction hole 13a, and the optical fiber 4 is passed through this tube.

[0040] The optical fiber introduction member 13 is formed in a columnar shape. The optical fiber introduction member 13 has a second insertion end portion 13b inserted into the optical fiber-side opening end portion 11b and an extending portion 13c protruding from the optical fiber-side opening end portion 11b. That is, the portion of the optical fiber introduction member 13 inserted into the optical fiber-side opening end portion 11b becomes the second insertion end portion 13b, and the portion of the optical fiber introduction member 13 not inserted into the optical fiber-side opening end portion 11b becomes the extending portion 13c.

[0041] On the outer peripheral surface of the second insertion end portion 13b, a second bulging portion 13d and a recessed portion 13e are formed. The second bulging portion 13d is a portion that protrudes outward in the radial direction of the second insertion end portion 13b. The second bulging portion 13d is disposed on the sensor-side opening end portion 11a side of the first bulging portion 11e and abuts against the first bulging portion 11e from the sensor-side opening end portion 11a side. That is, the maximum outer diameter of the second bulging portion 13d is larger than the minimum inner diameter of the first bulging portion 11e. The recessed portion 13e is an annular groove, and an O-ring 19 (second O-ring) is inserted into the recessed portion 13e. The O-ring 19 is a sealing member that is disposed between the optical fiber-side opening end portion 11b and the second insertion end portion 13b and seals the space between the optical fiber-side opening end portion 11b and the second insertion end portion 13b.

[0042] And the optical fiber-side opening end portion 11b is sealed by the optical fiber introduction member 13 and the O-ring 19. Therefore, the optical fiber introduction member 13 and the O-ring 19 function as a second sealing portion that seals the optical fiber-side opening end portion 11b.

[0043] On the end face of the second insertion end portion 13b, a screw hole 13f is formed. The screw hole 13f is a bottomed hole in which a screw groove of a female screw is formed. A screw 22 described later is screwed into the screw hole 13f. On the outer peripheral surface of the extending portion 13c, a male screw 13g is formed. The male screw 13g is a screw groove formed on the outer peripheral surface of the extending portion 13c.

[0044] The optical fiber introduction member 13 is shaped so as to be insertable and removable from the sensor-side opening end portion 11a side with respect to the unit case 11. Specifically, the maximum outer diameter of the second bulging portion 13d is equal to or less than the minimum inner diameters of the case central portion 11c and the sensor-side opening end portion 11a. That is, the minimum inner diameter of the portion on the optical fiber-side opening end portion 11b side of the unit case 11 rather than the first bulging portion 11e is equal to or greater than the maximum outer diameter of the second bulging portion 13d. Also, the maximum outer diameter of the extending portion 13c is equal to or less than the minimum inner diameter of the unit case 11. That is, the maximum outer diameter of the extending portion 13c is equal to or less than the minimum inner diameter of the first bulging portion 11e. And the optical fiber introduction member 13 is inserted into the unit case 11 from the sensor-side opening end portion 11a side, whereby the second insertion end portion 13b is inserted into the optical fiber-side opening end portion 11b and the second bulging portion 13d abuts on the first bulging portion 11e from the sensor-side opening end portion 11a side.

[0045] The nut 14 fixes the optical fiber introduction member 13 with respect to the unit case 11. A female screw 14a is formed on the inner peripheral surface of the nut 14. The female screw 14a is a screw groove formed on the inner peripheral surface of the nut 14 so as to be screwed onto the male screw 13g of the extending portion 13c.

[0046] When the female screw 14a is screwed onto the male screw 13g and the nut 14 is tightened to the optical fiber introduction member 13, the nut 14 abuts on the end surface of the optical fiber-side opening end portion 11b and the optical fiber introduction member 13 moves to the side opposite to the sensor-side opening end portion 11a. Therefore, when the nut 14 is tightened to the optical fiber introduction member 13, the length of the nut 14 and the position of the female screw 14a in the extending direction D of the unit case 11 are set so that the nut 14 abuts on the end surface of the optical fiber-side opening end portion 11b and the second bulging portion 13d abuts on the first bulging portion 11e from the sensor-side opening end portion 11a side.

[0047] Then, by tightening the nut 14 onto the optical fiber introduction member 13, the nut 14 abuts against the end face of the unit case 11, and the second bulging portion 13d abuts against the first bulging portion 11e from the sensor-side opening end portion 11a side. As a result, the first bulging portion 11e of the unit case 11 is sandwiched between the nut 14 and the second bulging portion 13d of the optical fiber introduction member 13, and the optical fiber introduction member 13 is fixed to the optical fiber-side opening end portion 11b. Therefore, the first bulging portion 11e, the second bulging portion 13d, the male screw 13g of the extending portion 13c, and the nut 14 function as a fixing mechanism for fixing the optical fiber introduction member 13 to the unit case 11.

[0048] As shown in FIGS. 2 to 6, the unit mounting member 15 is a plate-like member on which the power supply unit 3b and the communication unit 3c are mounted. The unit mounting member 15 is fixed to the sensor case 12 and the optical fiber introduction member 13. The unit mounting member 15 can be fixed to the sensor case 12, for example, by screwing a screw 21 passing through the unit mounting member 15 into the screw hole 12e of the sensor case 12. Similarly, the unit mounting member 15 can be fixed to the optical fiber introduction member 13, for example, by screwing a screw 22 passing through the unit mounting member 15 into the screw hole 13f of the optical fiber introduction member 13.

[0049] Next, a method for assembling the sensor module 3 will be described.

[0050] First, as shown in FIG. 7, the sensor case 12 and the optical fiber introduction member 13 are fixed to the unit mounting member 15 to form a unit. At this time, the first electric wire W1 and the second electric wire W2 are electrically connected by the sealing connector 16. Then, one or more optical fibers 4 are passed through the nut 14, the unit case 11, and the optical fiber introduction member 13, and one or more optical fibers 4 are connected to the power supply unit 3b and the communication unit 3c.

[0051] Next, as shown in FIGS. 7 and 8, the unit including the optical fiber introduction member 13, the unit mounting member 15, and the sensor case 12 is inserted into the unit case 11 from the sensor side opening end portion 11a side. Then, the female screw 11d of the sensor side opening end portion 11a and the male screw 12c of the first insertion end portion 12b are screwed together to fasten the first insertion end portion 12b to the sensor side opening end portion 11a. Thereby, the sensor side opening end portion 11a and the optical fiber side opening end portion 11b are sealed.

[0052] Next, as shown in FIGS. 8 and 2, the female screw 14a of the nut 14 and the male screw 13g of the extending portion 13c are screwed together to fasten the nut 14 to the extending portion 13c. Thereby, the optical fiber side opening end portion 11b is sealed and the optical fiber introduction member 13 is fixed to the optical fiber side opening end portion 11b.

[0053] As described above, in the sensor module 3 according to the present embodiment, since the unit case 11 that houses the power supply unit 3b and the communication unit 3c is formed of metal and has a cylindrical shape, it can have high pressure resistance. Further, since the unit case 11 is formed in a cylindrical shape with both ends open, the unit case 11 can be easily manufactured. And since the sensor side opening end portion 11a and the optical fiber side opening end portion 11b of the unit case 11 are sealed, it can have high water resistance. Therefore, the power supply unit 3b and the communication unit 3c can be protected against external factors such as water and pressure.

[0054] Further, in this sensor module 3, since the unit case 11 is made of stainless steel, it can have high pressure resistance and corrosion resistance at low cost. Thereby, the power supply unit 3b and the communication unit 3c can be protected against external factors such as water and pressure over a long period of time.

[0055] In addition, in this sensor module 3, since the sensor case 12 that houses one or more electric sensors 3d is made of metal, the electric sensors 3d can be appropriately protected. The sensor-side opening end portion 11a of the unit case 11 is sealed by a sensor case 12 having a first insertion end portion 12b inserted into the sensor-side opening end portion 11a, a sealing connector 16 that seals the opening 12a of the first insertion end portion 12b, and an O-ring 18 disposed between the sensor-side opening end portion 11a and the first insertion end portion 12b. Therefore, while electrically connecting the first electric wire W1 disposed in the unit case 11 and the second electric wire W2 disposed in the sensor case 12, the sensor-side opening end portion 11a of the unit case 11 can be sealed. Further, since both the sensor-side opening end portion 11a of the unit case 11 and the first insertion end portion 12b of the sensor case 12 that sandwich the O-ring 18 are made of metal, the space between the O-ring 18, the sensor-side opening end portion 11a of the unit case 11, and the first insertion end portion 12b of the sensor case 12 can be appropriately sealed.

[0056] In addition, in this sensor module 3, the optical fiber side opening end portion 11b of the unit case 11 is sealed by an optical fiber introduction member 13 having a second insertion end portion 13b inserted into the optical fiber side opening end portion 11b and an O-ring 19 disposed between the optical fiber side opening end portion 11b and the second insertion end portion 13b. Therefore, while introducing one or more optical fibers 4, the optical fiber side opening end portion 11b of the unit case 11 can be sealed.

[0057] In addition, in this sensor module 3, since the optical fiber introduction member 13 is fixed to the unit case 11, when the sensor module 3 is placed under a pressure water, it is possible to suppress the optical fiber introduction member 13 from being pushed into the unit case 11 by the external pressure.

[0058] Further, in this sensor module 3, the optical fiber introduction member 13 has an extending portion 13c that protrudes from the unit case 11, and the female screw 14a formed on the nut 14 is screwed onto the male screw 13g formed on the extending portion 13c. Therefore, by tightening the nut 14, the nut 14 abuts against the end face of the unit case 11, and the second bulging portion 13d of the optical fiber introduction member 13 abuts against the first bulging portion 11e of the unit case 11 from the side of the sensor-side opening end portion 11a. As a result, the first bulging portion 11e of the unit case 11 is sandwiched between the nut 14 and the second bulging portion 13d of the optical fiber introduction member 13, so that the optical fiber introduction member 13 can be appropriately fixed to the unit case 11.

[0059] Further, in this sensor module 3, a unit mounting member 15 on which a power supply unit 3b and a communication unit 3c are mounted is fixed to the sensor case 12 and the optical fiber introduction member 13, and the optical fiber introduction member 13 can be inserted into and removed from the unit case 11 from the side of the sensor-side opening end portion 11a. Therefore, by inserting and removing the optical fiber introduction member 13 into and from the unit case 11 from the side of the sensor-side opening end portion 11a, the unit mounting member 15 on which the power supply unit 3b and the communication unit 3c are mounted, and the sensor case 12 can also be integrally inserted into and removed from the unit case 11.

[0060] Further, in this sensor module 3, the maximum outer diameter of the extending portion 13c is equal to or less than the minimum inner diameter of the unit case 11, and the maximum outer diameter of the optical fiber introduction member 13 is equal to or less than the minimum inner diameter of the portion of the unit case 11 on the sensor-side opening end portion 11a side rather than the first bulging portion 11e. Therefore, the optical fiber introduction member 13 can be inserted into and removed from the unit case 11 from the side of the sensor-side opening end portion 11a.

[0061] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and may be modified without changing the gist described in each claim, or may be applied to other things.

[0062] For example, a wire cable or a rod may be attached to the sensor module, and the sensor module may be suspended by this wire cable or rod.

[0063] Also, when it is desired to fix the sensor module at a predetermined position within the hole, a packer may be attached to the sensor module or at a position separated from the sensor module. When attaching the packer, in addition to one or a plurality of optical fibers, an intake pipe or the like for inflating the packer is provided.

[0064] Also, the communication unit may perform two-way communication between the measuring device and the sensor module, or may perform one-way communication from the sensor module to the measuring device.

Explanation of Reference Numerals

[0065] 1... Monitoring system, 2... Measuring device, 2a... Light source unit, 2b... Communication unit, 3... Sensor module, 3a... Sensor section, 3b... Power supply unit, 3c... Communication unit, 3d... Electrical sensor, 3e... Profiler, 4... Optical fiber, 11... Unit case, 11a... Sensor-side opening end, 11b... Optical fiber-side opening end, 11c... Case central part, 11d... Female screw, 11e... First bulging part, 12... Sensor case, 12a... Opening, 12b... First insertion end, 12c... Male screw, 12d... Recess, 12e... Screw hole, 13... Optical fiber introduction member, 13a... Introduction hole, 13b... Second insertion end, 13c... Extending part, 13d... Second bulging part, 13e... Recess, 13f... Screw hole, 13g... Male screw, 14... Nut, 14a... Female screw, 15... Unit mounting member, 16... Sealing connector, 16a... Electric wire, 16b... Sealing part, 17... O-ring, 18... O-ring (first O-ring), 19... O-ring (second O-ring), 21... Screw, 22... Screw, D... Extending direction, S... Accommodation space, W1... First electric wire, W2... Second electric wire.

Claims

1. An electric sensor, A power supply unit that converts the light received from the optical fiber into electricity, A communication unit that converts the electrical signal received from the electric sensor into an optical signal, A metal unit case formed in a cylindrical shape with both ends open to accommodate the power supply unit and the communication unit, A first sealing portion that seals the sensor-side opening end portion, which is one end portion of the unit case, A second sealing portion that seals the optical fiber-side opening end portion, which is the other end portion of the unit case, and includes: A sensor module.

2. The unit case is made of stainless steel, The sensor module according to claim 1.

3. Further comprising a metal sensor case for accommodating the electric sensor, The sensor case has a first insertion end portion that is inserted into the sensor-side opening end portion and has an opening formed therein, The first sealing portion is, The sensor case, A sealing connector that seals the opening and electrically connects a first electric wire disposed in the unit case and a second electric wire disposed in the sensor case, A first O-ring disposed between the sensor-side opening end portion and the first insertion end portion to seal between the sensor-side opening end portion and the first insertion end portion, and has: The sensor module according to claim 1 or 2.

4. Further comprising a columnar optical fiber introduction member in which an introduction hole for hermetically introducing an optical fiber is formed, The optical fiber introduction member has a second insertion end portion that is inserted into the optical fiber-side opening end portion, The second sealing portion is, The optical fiber introduction member, A second O-ring disposed between the optical fiber-side opening end portion and the second insertion end portion to seal between the optical fiber-side opening end portion and the second insertion end portion, and has: The sensor module according to claim 3.

5. Further comprising a fixing mechanism for fixing the optical fiber introduction member to the unit case, The sensor module according to claim 4.

6. Further comprising a nut for fixing the optical fiber introduction member to the unit case, The optical fiber-side opening end portion has a first bulging portion that protrudes radially inward of the unit case, The optical fiber introduction member is, A second bulging portion formed on the outer peripheral surface of the second insertion end portion and abutting against the first bulging portion from the sensor-side opening end portion side, An extending portion protruding from the unit case, A male screw formed on the outer peripheral surface of the extending portion, and further has: The fixing mechanism is, The first bulging portion, the second bulging portion; the male screw of the extending portion; a nut having a female screw screwed onto the male screw of the extending portion; The sensor module according to claim 5.

7. further comprising a unit mounting member on which the power supply unit and the communication unit are mounted and which is fixed to the sensor case and the optical fiber introduction member; The optical fiber introduction member is shaped so as to be insertable and removable from the sensor-side opening end side with respect to the unit case. The sensor module according to claim 6.

8. The maximum outer diameter of the extending portion is equal to or less than the minimum inner diameter of the unit case; The maximum outer diameter of the optical fiber introduction member is equal to or less than the minimum inner diameter of the portion of the unit case on the sensor-side opening end side rather than the first bulging portion. The sensor module according to claim 7.

Images