Immersion type water level transmitter

Abstract

To provide an immersion type water level transmitter capable of preventing excessive pressure from being applied to a pressure sensor.SOLUTION: An immersion type water level transmitter of an embodiment comprises a measuring unit that measures a water level based on water pressure, a display unit that displays the water level measured by the measuring unit, and a cable that connects the measuring unit and the display unit. The measuring unit includes: a housing, a pressure-receiving diaphragm provided at an end of the housing and receiving water pressure; a pressure sensor provided inside the housing and detecting pressure; a transmission unit that transmits the water pressure from the pressure-receiving diaphragm to the pressure sensor; and an elastic body that connects the pressure sensor to the housing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE An embodiment of the present invention relates to a immersion type water level transmitter. [Background technology]

[0002] There is a submersible water level transmitter that measures the water level based on the water pressure by submerging a measuring unit having a pressure sensor in water. In such a submersible water level transmitter, if the pressure sensor is subjected to pressure (overpressure) that greatly exceeds the rated pressure, the pressure sensor may break down. Therefore, in such a submersible water level transmitter, it is necessary to suppress the application of overpressure to the pressure sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-124250 A Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a immersion type water level transmitter that can prevent excessive pressure from being applied to the pressure sensor. [Means for solving the problem]

[0005] The immersion type water level transmitter according to the embodiment includes a measuring unit that measures the water level based on the water pressure, a display unit that displays the water level measured by the measuring unit, and a cable that connects the measuring unit and the display unit. The measuring unit has a housing, a pressure-receiving diaphragm that is provided at an end of the housing and receives water pressure, a pressure sensor that is provided inside the housing and detects pressure, a transmitting unit that transmits the water pressure from the pressure-receiving diaphragm to the pressure sensor, and an elastic body that connects the pressure sensor and the housing. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a side view illustrating a immersion type water level transmitter according to an embodiment. [Diagram 2] 1 is a cross-sectional view showing a schematic diagram of a portion of a immersion type water level transmitter according to an embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view showing a schematic diagram of a portion of a immersion type water level transmitter according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view showing a schematic diagram of a portion of a immersion type water level transmitter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios of each part may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

[0008] FIG. 1 is a side view that diagrammatically illustrates a immersion type water level transmitter according to an embodiment. As shown in FIG. 1, a immersion type water level transmitter 100 according to the embodiment includes a measurement unit 10, a display unit 20, a cable 30, and a weight 40.

[0009] The measuring unit 10 measures the water level based on the water pressure. More specifically, the measuring unit 10 calculates the water level based on the difference between a reference pressure (e.g., atmospheric pressure) and the water pressure. The measuring unit 10 is submerged in water together with a weight 40. The structure of the measuring unit 10 will be described later.

[0010] The display unit 20 displays the water level measured by the measurement unit 10. The cable 30 connects the measurement unit 10 and the display unit 20. The measurement unit 10 transmits an electrical signal obtained by converting the measurement result (water level) to the display unit 20 via the cable 30. The display unit 20 displays the received measurement result (water level). The display unit 20 is installed, for example, on the ground.

[0011] The measurement unit 10 will be described in more detail below. 2 to 4 are cross-sectional views that diagrammatically show a portion of the immersion type water level transmitter according to the embodiment. FIG. 2 shows a state in which no pressure is applied to the measuring unit 10. FIG. 3 shows a state in which a pressure equal to or lower than the rated pressure is applied to the measuring unit 10. FIG. 4 shows a state in which a pressure exceeding the rated pressure is applied to the measuring unit 10. As shown in FIGS. 2 to 4, the measurement unit 10 has a housing 11, a pressure-receiving diaphragm 12, a pressure sensor 13, a transmission unit 14, a seal member 15, an elastic body 16, and a restriction unit 17.

[0012] The housing 11 is a hollow member. The housing 11 has an upper surface portion 11a, a lower surface portion 11b, and a side surface portion 11c. The upper surface portion 11a constitutes the upper end of the housing 11. The lower surface portion 11b constitutes the lower end of the housing 11. The side surface portion 11c connects the upper surface portion 11a and the lower surface portion 11b. In this example, the upper surface portion 11a is integral with the side surface portion 11c, and the lower surface portion 11b is separable from the side surface portion 11c. In this example, the housing 11 has a cylindrical shape.

[0013] The housing 11 further has a connection portion 11d provided therein. The connection portion 11d is provided on the inside of the side surface portion 11c. In this example, the connection portion 11d is a plate-like member parallel to the upper surface portion 11a. The connection portion 11d is provided with a first through hole 11p that passes through the connection portion 11d vertically. A part of the pressure sensor 13 (first pressure guiding portion 13b) is located inside the first through hole 11p. In addition, a part of the cable 30 (electric wire 31) passes through the first through hole 11p and is connected to the pressure sensor 13 (sensor portion 13a). The connection portion 11d is provided as necessary and can be omitted.

[0014] The lower surface portion 11b of the housing 11 is provided with a second through hole 11q that vertically penetrates the lower surface portion 11b. A seal member 15 is provided inside the second through hole 11q. The internal space of the housing 11 is divided by the seal member 15 into an upper space 11x and a lower space 11y. The upper space 11x is a portion of the internal space of the housing 11 that is above the seal member 15. The lower space 11y is a portion of the internal space of the housing 11 that is below the seal member 15. The seal member 15 is, for example, an O-ring.

[0015] Below the second through hole 11q of the lower surface portion 11b, there is provided a recess 11e recessed upward. The recess 11e is connected to the second through hole 11q and constitutes a part of the lower space 11y. The width of the recess 11e is larger than the width of the second through hole 11q. The recess 11e has a bottom surface 11f and a vertical surface 11g. The bottom surface 11f is continuous with the second through hole 11q. The vertical surface 11g extends downward from the bottom surface 11f. The depth of the recess 11e is, for example, several mm. As described later, the bottom surface 11f functions as a restricting portion 17 that restricts the deflection of the pressure-receiving diaphragm 12.

[0016] A pressure-receiving diaphragm 12 that receives water pressure is provided at the lower end of the housing 11. The pressure-receiving diaphragm 12 is provided below a recess 11e in the lower surface portion 11b of the housing 11 (i.e., at the lower end of the housing 11). The recess 11e is closed by the pressure-receiving diaphragm 12.

[0017] A pressure sensor 13 for detecting pressure is provided inside the housing 11. The pressure sensor 13 is provided in the upper space 11x of the housing 11. The pressure sensor 13 has a sensor portion 13a, a first pressure guiding portion 13b, and a second pressure guiding portion 13c. The first pressure guiding portion 13b is provided above the sensor portion 13a. The second pressure guiding portion 13c is provided below the sensor portion 13a.

[0018] The first pressure guiding part 13b is a cylindrical member extending upward from the sensor part 13a. The upper end of the first pressure guiding part 13b is located in the upper space 11x of the housing 11, and guides the pressure in the upper space 11x of the housing 11 to the sensor part 13a. The pressure in the upper space 11x of the housing 11 is the reference pressure. In this example, the pressure in the upper space 11x of the housing 11 is atmospheric pressure. Therefore, in this example, the reference pressure is atmospheric pressure. The pressure in the upper space 11x of the housing 11 does not have to be atmospheric pressure. In other words, the reference pressure does not have to be atmospheric pressure. By setting the reference pressure to atmospheric pressure, measurement errors due to temperature can be reduced.

[0019] The second pressure guiding portion 13c is a cylindrical member extending downward from the sensor portion 13a. The lower end of the second pressure guiding portion 13c is located in the lower space 11y of the housing 11, and guides the pressure in the lower space 11y of the housing 11 to the sensor portion 13a. The pressure in the lower space 11y of the housing 11 is the water pressure received by the pressure-receiving diaphragm 12.

[0020] Between the pressure-receiving diaphragm 12 and the pressure sensor 13 (second pressure guiding portion 13c), there is provided a transmission portion 14 that transmits water pressure from the pressure-receiving diaphragm 12 to the pressure sensor 13 (second pressure guiding portion 13c). In this example, the transmission portion 14 is a liquid sealed inside the lower space 11y and the second pressure guiding portion 13c of the housing 11. The liquid is, for example, oil. The seal member 15 closes the gap between the second through hole 11q and the second pressure guiding portion 13c, and prevents the liquid sealed inside the lower space 11y and the second pressure guiding portion 13c from leaking into the upper space 11x. The second pressure guiding portion 13c is slidable up and down inside the seal member 15.

[0021] 3, when water pressure is applied to the pressure-receiving diaphragm 12, the pressure-receiving diaphragm 12 bends toward the inside of the housing 11. When the pressure-receiving diaphragm 12 bends toward the inside of the housing 11, the volume of the lower space 11y becomes smaller, and the pressure applied to the liquid (transmitting portion 14) sealed in the lower space 11y is transmitted to the sensor portion 13a via the second pressure guiding portion 13c.

[0022] The pressure sensor 13 calculates the water level at the location where the measurement unit 10 is submerged based on the difference between a reference pressure (e.g., atmospheric pressure) applied from the first pressure guiding unit 13b and the water pressure applied from the second pressure guiding unit 13c.

[0023] The elastic body 16 connects the pressure sensor 13 and the housing 11. In this example, the elastic body 16 connects the pressure sensor 13 and the connection portion 11d. The elastic body 16 may be a spring or a member having elasticity such as rubber. In this example, the elastic body 16 is a coil spring. It is sufficient that at least one elastic body 16 is provided. In this example, a plurality of elastic bodies 16 are provided.

[0024] The elastic force of the elastic body 16 is adjusted to a value exceeding the rated pressure of the pressure sensor 13 and equal to or less than the pressure resistance limit value of the pressure sensor 13. For example, the elastic force of the elastic body 16 is preferably adjusted to a value slightly smaller than the pressure resistance limit value of the pressure sensor 13. For example, the elastic force of the elastic body 16 is preferably adjusted to a value between 80% and 90% of the pressure resistance limit value of the pressure sensor 13.

[0025] The pressure resistance limit is the maximum pressure at which the pressure sensor 13 does not break down. If pressure exceeding the pressure resistance limit is applied to the pressure sensor 13, the pressure sensor 13 will break down. The pressure resistance limit is, for example, about 10 times the rated pressure. The rated pressure of the pressure sensor 13 is, for example, several hundred kPa. The pressure resistance limit of the pressure sensor 13 is, for example, several thousand kPa. For example, when the measurable water level of the immersion type water level transmitter 100 is greater than 0 m and equal to or less than 20 m, the rated pressure of the pressure sensor 13 is about 200 kPa, and the pressure resistance limit of the pressure sensor 13 is about 2000 kPa.

[0026] In this example, the pressure sensor 13 further includes a support portion 13d that supports the sensor portion 13a. The support portion 13d is fixed to the sensor portion 13a and the second pressure guiding portion 13c. The elastic body 16 connects the support portion 13d and the connection portion 11d. The elastic body 16 may connect, for example, the sensor portion 13a and the connection portion 11d. In this case, the support portion 13d of the pressure sensor 13 can be omitted.

[0027] The cable 30 has an electric wire 31 and a cover 32. The electric wire 31 connects the pressure sensor 13 and the display unit 20. The pressure sensor 13 transmits an electric signal, which is a converted measurement result (water level), to the display unit 20 via the electric wire 31. The electric wire 31 is provided inside the hollow cover 32.

[0028] The cover 32 connects the upper surface 11a of the housing 11 to the display unit 20. By connecting the upper space 11x of the housing 11 to the display unit 20 by the hollow cover 32, the pressure in the upper space 11x of the housing 11 can be made atmospheric pressure. Note that if the reference pressure of the pressure sensor 13 is not atmospheric pressure, the hollow cover 32 can be omitted.

[0029] The behavior of the measuring unit 10 when pressure is applied will be described below. 2 and 3, when no pressure is applied to the pressure-receiving diaphragm 12 or when a pressure equal to or less than the rated pressure is applied to the pressure-receiving diaphragm 12, the pressure sensor 13 is held in a predetermined position by the elastic body 16. More specifically, when a pressure equal to or less than the rated pressure is applied to the pressure-receiving diaphragm 12, the pressure (water pressure) transmitted from the pressure-receiving diaphragm 12 to the pressure sensor 13 via the transmission unit 14 is less than the elastic force of the elastic body 16, so that the elastic body 16 does not contract and the pressure sensor 13 is held in a predetermined position. As a result, when a pressure equal to or less than the rated pressure is applied to the measurement unit 10 (pressure-receiving diaphragm 12), the pressure sensor 13 can measure the water pressure received by the pressure-receiving diaphragm 12.

[0030] 4, when pressure exceeding the elastic force of the elastic body 16 is applied to the pressure-receiving diaphragm 12, the pressure (water pressure) transmitted from the pressure-receiving diaphragm 12 to the pressure sensor 13 via the transmission unit 14 exceeds the elastic force of the elastic body 16, causing the elastic body 16 to contract and the pressure sensor 13 to move upward. This allows the pressure applied to the pressure sensor 13 to be reduced.

[0031] In this way, by providing the elastic body 16 between the pressure sensor 13 and the connection part 11d, it is possible to prevent excessive pressure from being applied to the pressure sensor 13 without increasing the size of the measurement part 10. As a result, even if excessive pressure is applied to the pressure-receiving diaphragm 12 when, for example, the measurement part 10 is submerged at a water depth equal to or greater than the measurement rated depth or when the pressure-receiving diaphragm 12 is touched during maintenance of the measurement part 10, it is possible to prevent excessive pressure from being applied to the pressure sensor 13. Therefore, it is possible to prevent the pressure sensor 13 from breaking down due to excessive pressure, and the reliability of the immersion type water level transmitter 100 can be improved.

[0032] 4, when pressure exceeding the elastic force of the elastic body 16 is applied to the pressure-receiving diaphragm 12, the pressure-receiving diaphragm 12 comes into contact with the bottom surface 11f of the recess 11e of the housing 11. As a result, the bottom surface 11f functions as a restricting portion 17 that restricts the deflection of the pressure-receiving diaphragm 12. The depth of the recess 11e is preferably adjusted to a depth such that, for example, when pressure exceeding the elastic force of the elastic body 16 and less than the pressure resistance limit value is applied to the pressure-receiving diaphragm 12, the pressure-receiving diaphragm 12 comes into contact with the bottom surface 11f.

[0033] In this way, by providing the restricting portion 17 that restricts the deflection of the pressure-receiving diaphragm 12, when pressure that exceeds the elastic force of the elastic body 16 is applied to the pressure-receiving diaphragm 12, the deflection of the pressure-receiving diaphragm 12 is restricted, and excessive pressure is prevented from being applied to the pressure sensor 13. In addition, since a portion of the pressure applied to the pressure-receiving diaphragm 12 can be released to the restricting portion 17, damage to the pressure-receiving diaphragm 12 can be suppressed.

[0034] The embodiment may include the following features.

[0035] (Configuration 1) A measuring unit that measures a water level based on a water pressure; A display unit that displays the water level measured by the measuring unit; A cable connecting the measurement unit and the display unit; Equipped with The measurement unit is A housing and a pressure-receiving diaphragm provided at an end of the housing and receiving water pressure; a pressure sensor provided inside the housing and detecting a pressure; a transmission section that transmits the water pressure from the pressure-receiving diaphragm to the pressure sensor; an elastic body that connects the pressure sensor and the housing; A immersion type water level transmitter having the above structure.

[0036] (Configuration 2) 2. The immersion type water level transmitter according to claim 1, wherein the measurement unit further includes a regulating unit that regulates the deflection of the pressure-receiving diaphragm.

[0037] As described above, according to the embodiment, a immersion type water level transmitter capable of preventing excessive pressure from being applied to the pressure sensor is provided.

[0038] Although some embodiments of the present invention have been illustrated above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. In addition, the above-mentioned embodiments can be implemented in combination with each other. [Explanation of symbols]

[0039] 10: Measurement section 11: Housing 11a:Top part 11b: Bottom part 11c: Side part 11d: Connection 11e: Recess 11f: Bottom 11g:Elevation 11p: 1st through hole 11q: 2nd through hole 11x: Upper space 11y: lower space 12: Pressure diaphragm 13: Pressure sensor 13a: Sensor section 13b: 1st pressure impulse part 13c: 2nd pressure impulse part 13d: Support part 14: Transmission section 15: Sealing material 16: Elastic body 17: Regulation Department 20: Display section 30: Cable 31: Electric wire 32: Cover 40: Weight 100: Immersion type water level transmitter

Claims

1. A measuring unit that measures a water level based on a water pressure; A display unit that displays the water level measured by the measuring unit; A cable connecting the measurement unit and the display unit; Equipped with The measurement unit is A housing and a pressure-receiving diaphragm provided at an end of the housing and receiving water pressure; a pressure sensor provided inside the housing and detecting a pressure; a transmission section that transmits the water pressure from the pressure-receiving diaphragm to the pressure sensor; an elastic body that connects the pressure sensor and the housing; A immersion type water level transmitter having the above structure.

2. The immersion type water level transmitter according to claim 1 , wherein the measurement unit further comprises a regulating unit that regulates the deflection of the pressure-receiving diaphragm.

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