Concentration meter

Abstract

To provide a concentration meter capable of measuring a reference value for phase difference. [Solution] The concentration meter comprises a flow channel section, a sealing section, a first transmitting section 21a, a first receiving section 21b, a second transmitting section 22a, a second receiving section 22b, and a processing section 30. The liquid to be measured flows through the flow channel section. Liquid is sealed inside the sealing section. The first receiving section faces the first transmitting section and receives microwaves transmitted from the first transmitting section and passing through the flow channel section. The second receiving section faces the second transmitting section and receives microwaves transmitted from the second transmitting section, passing through the flow channel section, the sealing section, and then through the flow channel section again. The processing section calculates a first difference between the phase of the microwaves transmitted from the first transmitting section and the phase of the microwaves received by the first receiving section, calculates a second difference between the phase of the microwaves transmitted from the second transmitting section and the phase of the microwaves received by the second receiving section, and calculates the concentration of the liquid to be measured in the flow channel section based on the difference between the second difference and the first difference.

Description

Technical Field

[0001] Embodiments of the present invention relate to a densitometer.

Background Art

[0002] There is a densitometer that measures the concentration of a liquid to be measured in a pipe based on the phase of microwaves. In this densitometer, microwaves are transmitted toward the liquid to be measured, and the phase difference generated in the microwaves is measured by passing through the liquid to be measured. The concentration of the liquid to be measured is calculated based on the amount of change from the reference value of the measured phase difference. As the reference value, for example, the phase difference (zero point) generated when microwaves pass through a liquid with a concentration of 0% is used. The amount of change from the reference value of the measured phase difference changes linearly with, for example, the concentration of the liquid to be measured. The reference value, the relational expression between the amount of change from the reference value of the phase difference and the concentration of the liquid to be measured, etc. are acquired in advance, for example, at the time of shipment of the densitometer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a densitometer capable of measuring the reference value of the phase difference.

Means for Solving the Problems

[0005] The concentration meter according to the embodiment includes a flow channel section, a sealing section, a first transmitting section, a first receiving section, a second transmitting section, a second receiving section, and a processing section. The liquid to be measured flows through the flow channel section. Liquid is sealed inside the sealing section. The first transmitting section transmits microwaves. The first receiving section faces the first transmitting section and receives microwaves transmitted from the first transmitting section and passing through the flow channel section. The second transmitting section transmits microwaves. The second receiving section faces the second transmitting section and receives microwaves transmitted from the second transmitting section, passing through the flow channel section, the sealing section, and further passing through the flow channel section. The processing section calculates a first difference between the phase of the microwaves transmitted from the first transmitting section and the phase of the microwaves received by the first receiving section. The processing section calculates a second difference between the phase of the microwaves transmitted from the second transmitting section and the phase of the microwaves received by the second receiving section. The processing unit calculates the concentration of the liquid to be measured in the flow path based on the difference between the second difference and the first difference. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram illustrating a concentration meter according to the embodiment. [Figure 2] This is a schematic cross-sectional view illustrating the tube portion of a concentration meter according to an embodiment. [Figure 3] This is a schematic cross-sectional view illustrating the tube portion of a concentration meter according to an embodiment. [Figure 4] This is a schematic diagram illustrating microwaves. [Modes for carrying out the invention]

[0007] Each embodiment of the present invention will be described below with reference to the drawings. In this specification and in each figure, elements similar to those already described are denoted by the same reference numerals, and detailed explanations are omitted as appropriate.

[0008] Figure 1 is a schematic diagram illustrating a concentration meter according to an embodiment. The concentration meter 100 according to this embodiment is, for example, an in-line type microwave concentration meter. As shown in Figure 1, the concentration meter 100 includes a tube section 10, a first transmitting section 21a, a first receiving section 21b, a second transmitting section 22a, a second receiving section 22b, and a processing section 30.

[0009] The pipe section 10 is connected to a pipe 70 installed in a facility, for example. The liquid whose concentration is to be measured (the liquid to be measured L1, as shown in Figure 2 below) flows through the pipe 70. With both ends of the pipe section 10 connected to the pipe 70, the liquid to be measured L1 flows through the pipe section 10 (the flow path section 11, described later) in the first direction D1. In other words, the pipe section 10 is inserted into the flow path of the liquid to be measured L1 formed by the pipe 70 and becomes part of the flow path of the liquid to be measured L1.

[0010] The piping 70 is, for example, a water supply or a sewer. The liquid to be measured L1 is a liquid (water) containing sludge flowing through the water supply or sewer. The concentration meter 100 measures, for example, the concentration of sludge contained in the liquid to be measured L1 (e.g., TS (Total Solids) concentration).

[0011] The first transmitting unit 21a and the second transmitting unit 22a are transmitting antennas that transmit electromagnetic waves (microwaves in this example). The wavelengths of the microwaves transmitted from the first transmitting unit 21a and the second transmitting unit 22a may be the same. The first receiving unit 21b is a receiving antenna that receives microwaves transmitted from the first transmitting unit 21a. The second receiving unit 22b is a receiving antenna that receives microwaves transmitted from the second transmitting unit 22a.

[0012] The processing unit 30 includes an arithmetic circuit connected to the transmitting and receiving unit (first transmitting unit 21a, first receiving unit 21b, second transmitting unit 22a, second receiving unit 22b). The processing unit 30 includes, for example, a controller that controls the transmission and reception of microwaves in the transmitting and receiving unit. The processing unit 30 acquires information such as the phase of microwaves transmitted from the transmitting unit (first transmitting unit 21a, second transmitting unit 22a) and information such as the phase of microwaves received by the receiving unit (first receiving unit 21b, second receiving unit 22b), and calculates the concentration.

[0013] Figures 2 and 3 are schematic cross-sectional views illustrating the tubing portion of the concentration meter according to this embodiment. Figure 2 shows a cross-section along the line A1-A2 shown in Figure 1. That is, Figure 2 shows a cross-section perpendicular to the first direction D1 (the direction in which the liquid L1 to be measured flows through the pipe section 10). Figure 3 shows a cross-section along the line A3-A4 as shown in Figure 2. In other words, Figure 3 is a cross-section along the first direction D1.

[0014] In this example, the tube section 10 is cylindrical. The tube section 10 is divided into a flow channel section 11 and a sealing section 12 by a partition wall 13. The flow channel section 11 is cylindrical with both ends open. The liquid to be measured L1 flows into the flow channel section 11 through the opening at one end of the flow channel section 11. The liquid to be measured L1 flows out of the flow channel section 11 through the opening at the other end of the flow channel section 11.

[0015] The inside of the sealing section 12 is a closed space, and liquid L2 is sealed inside. This space is filled with liquid L2. Liquid L2 is, for example, water (clean water) with a concentration of zero.

[0016] The partition wall 13 includes a first wall section 13a, a second wall section 13b, and a third wall section 13c. The second wall section 13b is aligned with the first wall section 13a in the second direction D2 and faces the first wall section 13a. The first wall section 13a and the second wall section 13b each extend from the inner surface 10i of the pipe section 10 along the third direction D3. The third wall section 13c extends in the second direction D2 and connects the first wall section 13a and the second wall section 13b. The first direction D1, the second direction D2, and the third direction D3 are mutually orthogonal directions.

[0017] The sealed section 12 includes a space enclosed by the partition wall 13 (first wall section 13a, second wall section 13b, third wall section 13c) and a part of the side surface of the pipe section 10. The flow path section 11 includes a space enclosed by another part of the side surface of the pipe section 10 and the partition wall 13.

[0018] The portion through which the measurement liquid L1 in the flow path portion 11 flows includes a first portion 11a arranged in the third direction D3 with the enclosure portion 12. The portion through which the measurement liquid L1 in the flow path portion 11 flows further includes a second portion 11b and a third portion 11c arranged in the second direction D2 with the enclosure portion 12. The enclosure portion 12 is between the second portion 11b and the third portion 11c.

[0019] On the side surface 11W (side wall) of the flow path portion 11, a first transmission window portion 14a, a first reception window portion 14b, a second transmission window portion 15a, and a second reception window portion 15b are provided. When the measurement liquid L1 flows in the flow path portion 11, the inner surfaces of these transmission / reception window portions are in contact with the measurement liquid L1 in the flow path portion 11. The outer surfaces of the transmission / reception window portions are exposed outside the pipe portion 10.

[0020] Also, a first window portion 16a is provided in the first wall portion 13a, and a second window portion 16b is provided in the second wall portion 13b. When the measurement liquid L1 flows in the flow path portion 11, one surface of the first window portion 16a and one surface of the second window portion 16b are in contact with the measurement liquid L1. The surfaces on the opposite sides of the first window portion 16a and the second window portion 16b are in contact with the liquid L2 in the enclosure portion 12.

[0021] For these window portions (the first transmission window portion 14a, the first reception window portion 14b, the second transmission window portion 15a, the second reception window portion 15b, the first window portion 16a, the second window portion 16b), a material with a higher transmittance for microwaves is used compared to the material around the window portion of the pipe portion 10. For example, the material of the window portion is polysulfone. For example, the material of the portion other than the window portion of the pipe portion 10 is stainless steel.

[0022] The first transmission window portion 14a and the first reception window portion 14b are arranged side by side in the second direction D2 through the central portion (first portion 11a) of the flow path portion 11. The first transmission portion 21a is provided adjacent to the first transmission window portion 14a. The first reception portion 21b is provided adjacent to the first reception window portion 14b so as to face the first transmission portion 21a in the second direction D2.

[0023] The microwaves transmitted from the first transmitting unit 21a pass through the first transmitting window 14a, the flow path 11 (the liquid to be measured L1 in the first part 11a), and the first receiving window 14b in that order, and are received by the first receiving unit 21b.

[0024] The second transmitting window 15a and the second receiving window 15b are aligned in the second direction D2 via the sealing section 12. The first window 16a and the second window 16b are located between the second transmitting window 15a and the second receiving window 15b. The second transmitting section 22a is provided adjacent to the second transmitting window 15a. The second receiving section 22b is provided adjacent to the second receiving window 15b so as to face the second transmitting section 22a in the second direction D2.

[0025] The microwaves transmitted from the second transmitting unit 22a pass through the second transmitting window 15a, the flow channel 11 (the liquid L1 to be measured in the second part 11b), the first window 16a, the sealing part 12 (liquid L2), the second window 16b, the flow channel 11 (the liquid L1 to be measured in the third part 11c), and the second receiving window 15b in that order, and are received by the second receiving unit 22b.

[0026] Figure 4 is a schematic diagram illustrating microwaves. The propagation speed of microwaves varies depending on the physical properties of the propagation medium (e.g., dielectric constant, conductivity, and permeability). Since the dielectric constant changes with the concentration of a liquid, the concentration of the liquid can be calculated based on the change in microwave propagation speed. This change in propagation speed is understood as a phase difference. For example, the higher the concentration, the larger the phase difference.

[0027] The processing unit 30 calculates the difference (θs: first difference) between the phase of the microwave transmitted from the first transmitting unit 21a and the phase of the microwave received by the first receiving unit 21b.

[0028] The processing unit 30 calculates the difference (θr: second difference) between the phase of the microwave transmitted from the second transmitting unit 22a and the phase of the microwave received by the second receiving unit 22b.

[0029] The processing unit 30 calculates the difference between θr and θs (Δθ = θs - θr: phase change). Based on the Δθ (phase change) measured in this way and a predetermined relationship formula between Δθ and the concentration of the liquid, the processing unit 30 calculates the concentration of the liquid to be measured L1.

[0030] For example, the concentration meter 100 may be equipped with a memory device that stores a previously acquired relationship between Δθ and concentration. Also, even with liquids of the same concentration, the phase may change depending on the temperature of the liquid. Therefore, a thermometer for measuring the temperature of the liquid L1 to be measured may be provided in the tube section 10. The processing unit 30 may make appropriate corrections using the temperature of the liquid L1 to be measured.

[0031] As explained above, the processing unit 30 calculates the concentration based on the difference (Δθ) between θs and θr, with θr as the reference value (zero point). By providing the sealing unit 12, the second transmitting unit 22a, the second receiving unit 22b, etc., the reference value of the phase difference (second difference: θr) can be measured.

[0032] According to the embodiment, for example, a reference value of the phase difference can be measured when the liquid to be measured L1 is flowing in the tube section 10. For example, the phase difference (reference value) generated in the microwaves transmitted and received by the first transmitting section 21a and the first receiving section 21b can be measured simultaneously with the phase difference (reference value) generated in the microwaves transmitted and received by the second transmitting section 22a and the second receiving section 22b. That is, for example, the phase difference generated by the microwaves passing through the liquid to be measured L1 in the flow path section 11 can be measured simultaneously with the phase difference generated by the microwaves passing through the liquid L2 in the sealing section 12.

[0033] Incidentally, there is a reference example of a concentration meter that uses ultrasound. In this reference example concentration meter, the concentration of the liquid to be measured is measured based on the attenuation of the ultrasonic intensity caused by the ultrasound passing through the liquid to be measured in the tube. On the other hand, the inner surface of the tube 10 is in contact with the liquid to be measured L1, and dirt may adhere to the inner surface of the tube 10. Since the intensity of the ultrasound is also attenuated by the dirt adhering to the inner surface of the tube, the method of measuring concentration by the intensity of ultrasound can be greatly affected by the adhesion of dirt and may result in errors. In contrast, a concentration meter that measures concentration by the phase difference of microwaves is less affected by the adhesion of dirt. However, even with the phase difference of microwaves, the effect of the adhesion of dirt is not entirely absent.

[0034] In the concentration meter 100 according to the embodiment, it is possible that dirt or other deposits may be attached to the inner surface of the tube section 10. The microwaves transmitted and received by the first transmitting section 21a and the first receiving section 21b pass through the inner surface of the tube section 10 (the inner surfaces of the first transmitting window section 14a and the first receiving window section 14b).

[0035] The microwaves transmitted and received by the second transmitting unit 22a and the second receiving unit 22b also pass through the inner surface of the tube section 10 (the inner surfaces of the second transmitting window section 15a and the second receiving window section 15b). Therefore, for example, the reference value of the phase difference calculated from the microwaves transmitted and received by the second transmitting unit 22a and the second receiving unit 22b will reflect the deposits on the inner surface of the tube section 10. In other words, when the phase difference of the microwaves is affected by deposits on the inner surface of the tube section 10, the reference value can also be set to a value that takes similar deposits into account. This makes it possible to calculate the concentration accurately even when, for example, dirt or other deposits are present on the inner surface of the tube section 10. For example, the frequency of cleaning to remove deposits can be reduced.

[0036] As described above, in this example, the sealing section 12 is provided by partitioning the pipe section 10 with a partition wall 13. In other words, the flow path section 11 and the sealing section 12 are integrally formed with the pipe section 10, and the relative positional relationship between the flow path section 11 and the sealing section 12 does not shift. For example, the pipe section 10 is easy to handle and easy to connect to the piping 70 of the equipment.

[0037] As shown in Figure 2, the length Lb of the third direction D3 of the sealing section 12 is less than the radius of the pipe section 10 (for example, less than half the radius). The cross-sectional area of ​​the sealing section 12 is smaller than the cross-sectional area of ​​the flow path section 11. The volume of the sealing section 12 is smaller than the volume of the flow path section 11. This allows for, for example, suppression of pressure loss.

[0038] For example, the length La of the encapsulation section 12 in the second direction D2 is longer than the length Lb of the encapsulation section 12 in the third direction D3. For example, the distance (length La) that microwaves transmitted from the second transmitting section 22a travel through the encapsulation section 12 is longer than the distance that microwaves travel through the flow path section 11 (sum of length Lc and length Ld). This makes it possible to reduce the size of the encapsulation section 12 while ensuring that the microwaves have enough length to pass through it. For example, the length La of the encapsulation section 12 in the second direction D2 may be longer than the radius of the tube section 10 (half of the outer or inner diameter).

[0039] According to the embodiment, a concentration meter capable of measuring a reference value of the phase difference can be provided.

[0040] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only 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, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. [Explanation of Symbols]

[0041] 10: Pipe part 10i: Inner surface 11: Flow channel 11W: Side 11a: 1st part 11b:Second part 11c: 3rd part 12: Enclosed section 13: Partition wall 13a: 1st wall part 13b:Second wall part 13c: Third wall 14a: First transmission window section 14b: First receiving window section 15a: Second transmission window section 15b: Second receiving window section 16a: First Window Section 16b: Second Window Section 21a: First transmitting unit 21b: First receiving unit 22a: Second transmitting unit 22b: Second receiving unit 30: Processing Unit 70: Piping 100: Concentration meter D1~3: 1st~3rd direction L1: Liquid to be measured L2:Liquid La, Lb, Lc, Ld: Length

Claims

1. The channel through which the liquid to be measured flows, A sealed section containing liquid, A first transmitting unit that transmits microwaves, A first receiving unit facing the first transmitting unit, which receives microwaves transmitted from the first transmitting unit and passing through the flow path unit, A second transmitting unit that transmits microwaves, A second receiving unit facing the second transmitting unit, which receives microwaves transmitted from the second transmitting unit, passing through the flow path and the sealing unit, and further passing through the flow path; A processing unit that calculates a first difference between the phase of microwaves transmitted from the first transmitting unit and the phase of microwaves received by the first receiving unit, calculates a second difference between the phase of microwaves transmitted from the second transmitting unit and the phase of microwaves received by the second receiving unit, and calculates the concentration of the liquid to be measured in the flow channel based on the difference between the second difference and the first difference, A concentration meter equipped with a device.

2. The pipe section includes the flow channel section and the sealing section, The concentration meter according to claim 1, wherein the tube portion is divided into a flow path portion and a sealing portion by a partition wall extending from the inner surface of the tube portion.

3. The second transmitting unit and the second receiving unit are arranged in a second direction perpendicular to the first direction in which the liquid to be measured flows within the flow path, The concentration meter according to claim 1 or 2, wherein the length of the sealing portion along the second direction is longer than the length of the sealing portion along the third direction perpendicular to the first and second directions.

4. The concentration meter according to claim 1 or 2, wherein the distance the microwave transmitted from the second transmitting unit travels through the encapsulation section is longer than the distance the microwave transmitted from the second transmitting unit travels through the flow path section.

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