JP2022175729A - measuring device - Google Patents

Abstract

To certainly measure the degree of contamination even if positional deviation of a light emitting element or a light receiving element occurs.SOLUTION: A measuring device comprises: piping in which liquid passes, the piping at least partially formed of light transmissive material; a light irradiation unit having a first light emitting element that continuously irradiates the liquid with light and a first substrate that is provided with the first light emitting element; a light receiving unit having a first light receiving element that continuously receives light and a second substrate that is provided with the first light receiving element; a housing that is provided with the first substrate and the second substrate; and a contamination degree measuring unit that measures the degree of contamination of the liquid based on an output signal from the light receiving unit. The housing is provided with holes, and the piping is inserted into the holes. The first light emitting element and the first light receiving element are arranged with the piping therebetween. An optical axis of the first light emitting element overlaps a light receiving area of the first light receiving element.SELECTED DRAWING: Figure 1

Description

The present invention relates to measuring devices.

Patent Document 1 discloses a particle detection signal that is a signal generated by amplifying an electrical signal converted by a light receiving section by a first magnification, and a second magnification that is smaller than the first magnification of the electrical signal converted by the light receiving section. Disclosed is a measuring device that generates a signal for measuring the degree of contamination of a liquid based on a bubble detection signal, which is a signal generated by amplifying at .

JP 2016-45033 A

In the invention described in Patent Document 1, light emitted from one light-emitting element is received by two light-receiving elements, so it is necessary to apply light to the two light-receiving elements evenly. However, when the measuring device is installed in construction machinery and operated at high temperatures, the mounting substrate for the light emitting element and the light receiving element will be thermally deformed, and the light will not hit the two light receiving elements evenly, resulting in an increase in the degree of contamination. Measurement may not be possible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring apparatus capable of reliably measuring the degree of contamination even when a light emitting element or a light receiving element is misaligned.

In order to solve the above problems, the measuring device according to the present invention includes, for example, a pipe through which a liquid passes, at least a part of which is formed of a light-transmitting material, and a pipe that continuously transmits light. A light irradiation unit having a first light emitting element for irradiation and a first substrate provided with the first light emitting element, a first light receiving element for continuously receiving light, and the first light receiving element are provided. a light-receiving unit including a second substrate; a housing provided with the first substrate and the second substrate; a degree measuring unit, wherein a hole is provided in the housing, the pipe is inserted into the hole, and the first light emitting element and the first light receiving element are arranged with the pipe interposed therebetween. and the optical axis of the first light emitting element overlaps with the light receiving area of the first light receiving element.

According to the measuring device of the present invention, the pipe through which the liquid passes and at least a part of which is made of a light-transmitting material is inserted into the hole provided in the housing, and the A housing is provided with a first substrate provided with one light-emitting element and a second substrate provided with a first light-receiving element. The first light-emitting element and the first light-receiving element are arranged across the pipe, and the optical axis of the first light-emitting element overlaps the light-receiving region of the first light-receiving element. As a result, the degree of contamination can be reliably measured even if the positions of the light-emitting element and the light-receiving element are misaligned.

The light emitting section has at least a second light emitting element that continuously emits light, the light receiving section has at least a second light receiving element that continuously receives light, and the second light emitting element and the second light-receiving element may be arranged across the pipe, and the optical axis of the second light-emitting element may overlap the light-receiving region of the second light-receiving element. Thereby, the measurement accuracy of the degree of contamination can be improved. This case includes the case where the number of light-emitting elements and light-receiving elements is three or more.

The second light-emitting element is provided adjacent to the first light-emitting element, the second light-receiving element is provided adjacent to the first light-receiving element, and the contamination degree measuring unit includes the The degree of contamination of the liquid may be measured based on the difference between the output signal from the first light receiving element and the output signal from the second light receiving element. This makes it possible to measure the degree of contamination while removing the effects of air bubbles.

The contamination degree measuring unit detects particles having a particle size within a first range based on the output signal from the first light receiving element, and detects particles having a particle size within the first range based on the output signal from the second light receiving element. Particles contained in a second range different from the first range may be detected. This makes it possible to measure the degree of contamination for each particle diameter.

A shift between the optical axis of the first light emitting element and the optical axis of the first light receiving element may be 50 μm or less. This makes it possible to increase the intensity of light incident on the light receiving element when the light emitting element or the light receiving element is misaligned.

According to the present invention, the degree of contamination can be reliably measured even if the positions of the light-emitting element and the light-receiving element are misaligned.

1 is a cross-sectional view showing an outline of a measuring device 1; FIG. 2 is a block diagram showing an outline of the electrical configuration of the measuring device 1; FIG. 2 is a cross-sectional view showing the outline of the measuring device 2. FIG. 2 is a block diagram showing an outline of an electrical configuration of the measuring device 2; FIG. 3 is a cross-sectional view showing the outline of the measuring device 3. FIG. 3 is a block diagram showing an outline of an electrical configuration of the measuring device 3; FIG. It is a figure which shows the outline of the conventional measuring apparatus 100. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The measuring device of the present invention is provided at a desired position of a device that performs a desired operation using liquid, such as construction machinery and hydraulic equipment, and measures the degree of contamination of the liquid.

<First Embodiment>
FIG. 1 is a cross-sectional view showing the outline of the measuring device 1. As shown in FIG. In addition, in FIG. 1, the hatching which shows a cross section is partially abbreviate|omitted. The measuring device 1 mainly has a light irradiation section 10 , a light receiving section 20 , a housing 30 and a pipe 39 .

The light irradiation section 10 mainly has a light emitting element 11 and a substrate 15 provided with the light emitting element 11 . The light emitting element 11 is, for example, an LED, and irradiates the inside of the pipe 39 with light.

The light receiving section 20 mainly has a light receiving element 21 and a substrate 25 on which the light receiving element 21 is provided. The light-receiving element 21 is, for example, a photodiode (PD), and detects transmitted light due to light irradiation.

The light emitting element 11 and the light receiving element 21 are arranged with a pipe 39 interposed therebetween. Also, the optical axis ax1 of the light emitting element 11 overlaps the light receiving area of the light receiving element 21 . The light-receiving region is a region in which incident light can be detected, and the light-receiving element 21 converts the light incident on the light-receiving region into an electrical signal. For example, when the light receiving element 21 is a photodiode, the inner area surrounded by the annular electrode is the light receiving area.

In FIG. 1, the optical axis ax1 of the light emitting element 11 is aligned with the optical axis ax2 of the light receiving element 21, but the optical axis ax1 and the optical axis ax2 may not be aligned.

At least a part of the pipe 39 is made of a light-transmitting material, and the liquid to be measured, such as oil or water, passes through the pipe 39 . The light emitting element 11 irradiates the portion of the pipe 39 made of the light transmissive material with light from one side, and the light receiving element 21 receives the light from the other side.

The pipe 39 may be entirely made of a light-transmissive material, or partially formed with a window for introducing and leading light. In FIG. 1, the pipe 39 is entirely made of a light transmissive material.

The pipe 39 is provided inside the housing 30 . The housing 30 mainly has a first housing 31 , a second housing 32 and a third housing 33 .

The first housing 31 is provided with holes 31a provided at both ends thereof, and a hole 31b connecting the two holes 31a. The central axis of the hole 31a and the central axis of the hole 31b are substantially aligned.

A pipe 39 is inserted into the hole 31b, and a second housing 32 is inserted into each of the holes 31a. A portion of the third housing 33 is inserted outside the second housing 32 into the hole 31a. A female threaded portion 31c is formed in the hole 31a, and the male threaded portions 32a and 33a formed on the outer peripheral surfaces of the second housing 32 and the third housing 33 are screwed together so that the second housing 32 and the third housing 33 are screwed together. 3 housing 33 is provided in the hole 31a.

Holes 32b and 33b are provided in the second housing 32 and the third housing 33, respectively. The holes 32b and 33b communicate with the hollow portion of the pipe 39 and serve as flow paths for the liquid.

In this embodiment, the second housing 32 and the third housing 33 are separate members, but the second housing 32 and the third housing 33 may be one member.

The first housing 31 has recesses 31d and 31e. A substrate 15 is provided in the recess 31d, and a substrate 25 is provided in the recess 31e. A hole 31g is provided in the bottom surface of the recess 31d, and the light emitting element 11 is provided in the hole 31g. A hole 31f is provided in the bottom surface of the concave portion 31e, and the light emitted from the light emitting element 11 enters the light receiving element 21 through the pipe 39 and the hole 31f.

FIG. 2 is a block diagram showing an outline of the electrical configuration of the measuring device 1. As shown in FIG. The measuring device 1 has a contamination degree measuring unit 41 , an output unit 43 and a display unit 45 . Further, the light irradiation section 10 has a driving circuit 17 and the light receiving section 20 has an amplifier 27 .

The light-emitting element 11 is driven by a driving circuit 17 . The drive circuit 17 includes a constant current circuit or the like that keeps the amount of light emitted by the light emitting element 11 constant. The drive circuit 17 causes the light emitting element 11 to emit light continuously. The light receiving element 21 continuously receives the light emitted from the light emitting element 11 and passed through the liquid. The drive circuit 17 may include an APC circuit that feeds back the amount of light received by the light receiving element 21 .

The output signal of the light receiving element 21 is amplified by the amplifier 27 and then input to the contamination degree measuring section 41 . The contamination level measurement unit 41 measures the contamination level of the liquid based on the output signal from the light receiving element 21 . If the liquid contains particles, the amount of light blocked by the particles does not enter the light receiving element 21 . The contamination level measurement unit 41 measures the amount of particles contained in the liquid, that is, the contamination level, based on the number of times and the time that the output signal from the light receiving element 21 is interrupted. Since a known method can be used for the processing of the contamination degree measuring unit 41, the description thereof is omitted.

An output unit 43 is connected to the contamination level measurement unit 41 . A display, a processing device, a storage device, a communication device, a construction machine, and the like are connected to the output unit 43 . The measurement results are displayed on a display, stored in a storage device, or output to a construction machine via a communication machine and displayed on the construction machine. In this embodiment, a display unit 45 is connected to the output unit 43 . Note that the output unit 43 may output the measurement result to an external output device or the like via a network (whether wired or wireless).

Returning to the description of FIG. The measuring device 1 is installed in a construction machine or the like, and the measuring device 1 is used in an environment of 100 degrees or more during operation of the machine. In a high-temperature environment, the substrates 15 and 25 are thermally deformed, which causes the light-emitting element 11 and the light-receiving element 21 to move in a direction substantially perpendicular to the optical axes ax1 and ax2 (horizontal direction in FIG. 1).

However, since the light-emitting element 11 and the light-receiving element 21 correspond 1:1, even if the light-emitting element 11 and the light-receiving element 21 are misaligned, strong light emitted from near the front of the light-emitting element 11 will not be emitted. Incident into the light receiving element 21 .

According to the present embodiment, even if the optical axis ax1 and the optical axis ax2 are misaligned due to thermal deformation, the strong light irradiated from near the front of the light emitting element 11 is incident on the light receiving element 21. Therefore, the measurement apparatus 1 can reliably measure the degree of contamination.

In the present embodiment, the light irradiation unit 10 and the light receiving unit 20 are provided in the housing 30 so that the optical axis ax1 overlaps the light receiving area of the light receiving element 21. However, the intensity of the light incident on the light receiving element 21 is In order to increase the strength, it is desirable that the deviation between the optical axis ax1 and the optical axis of the light receiving element 21 is 50 μm or less.

<Second Embodiment>
Although the first embodiment of the present invention has one set of light-emitting elements and light-receiving elements, the number of light-emitting elements and light-receiving elements is not limited to this. A second embodiment of the present invention has two sets of light emitting elements and light receiving elements. A measuring device 2 according to the second embodiment will be described below. The same reference numerals are assigned to the same parts as in the first embodiment, and the description thereof is omitted.

FIG. 3 is a cross-sectional view showing the outline of the measuring device 2. As shown in FIG. In addition, in FIG. 3, the hatching which shows a cross section is partially abbreviate|omitted. The measuring device 2 mainly includes a light irradiation section 10A, a light receiving section 20A, a housing 30A, and a pipe 39. As shown in FIG.

10 A of light irradiation parts mainly have the two light emitting elements 11 and the board|substrate 15. As shown in FIG. The two light emitting elements 11 are provided adjacent to each other. The light receiving section 20A mainly has two light receiving elements 21 and a substrate 25 . The two light receiving elements 21 are provided adjacently. The optical axis ax1 of the light emitting element 11 overlaps with the light receiving area of the light receiving element 21, respectively. In FIG. 3, the optical axis ax1 of the light emitting element 11 is aligned with the optical axis ax2 of the light receiving element 21, but the optical axis ax1 and the optical axis ax2 may not be aligned.

Hereinafter, the light emitting element 11 and the light receiving element 21 on the upstream side are referred to as a light emitting element 11a and a light receiving element 21a, and the light emitting element 11 and the light receiving element 21 on the downstream side are referred to as a light emitting element 11b and a light receiving element 21b.

The housing 30A mainly has a first housing 31A, a second housing 32, and a third housing 33. As shown in FIG. The first housing 31A has recesses 31d and 31e, a hole 31h provided in the bottom surface of the recess 31d, and a hole 31i provided in the bottom surface of the recess 31e. Two light emitting elements 11 are inserted in the hole 31h. Light emitted from the light emitting element 11 enters the light receiving element 21 through the pipe 39 and the hole 31i.

FIG. 4 is a block diagram showing an outline of the electrical configuration of the measuring device 2. As shown in FIG. The measuring device 2 has a contamination degree measuring section 41A, an output section 43, and a display section 45. As shown in FIG. Further, the light irradiation section 10A has a driving circuit 17, and the light receiving section 20A has an amplifier 27 and an adder/subtractor 28. As shown in FIG.

The drive circuit 17 drives the two light emitting elements 11 to make the outputs of the two light emitting elements 11 the same. Each of the two light receiving elements 21 continuously receives the light emitted from the light emitting element 11 and passed through the liquid. Output signals from the two light receiving elements 21 are amplified by amplifiers 27, respectively. The amplifier 27 that amplifies the signal of the light receiving element 21a is referred to as an amplifier 27a, and the amplifier 27 that amplifies the signal of the light receiving element 21b is referred to as an amplifier 27b.

The output signal of the light receiving element 21a is input to the adder/subtractor 28 after being amplified by the amplifier 27a, and the output signal of the light receiving element 21b is input to the adder/subtractor 28 after being amplified by the amplifier 27b. An adder/subtractor 28 provides a differential output of the light receiving element 21 (21a, 21b). Since the output signal from the light receiving element 21 is a continuous signal, the differential output of the light receiving element 21 is also a continuous signal.

The differential output is input to the contamination level measuring section 41A. Then, the contamination level measurement unit 41A measures the amount of particles contained in the liquid flowing through the pipe 39 based on the differential output of the light receiving element 21 . Hereinafter, the principle of measuring the amount of particles by the contamination level measuring unit 41A will be described, taking as an example the case where the particles D are flowing in the flow path toward the position of x1→x5.

Since the outputs of the light-emitting elements 11a and 11b are the same, the amount of light entering the light-receiving element 21 is the same when there is no impurity particle such as the particle D, and the differential output is zero. When the particle D is at the position x1, the amount of light entering the light receiving element 21 is the same, so the differential output is zero.

When the particle D is at the position x2, the amount of light received by the light receiving element 21a is blocked by the particle D and becomes smaller than the amount of light received by the light receiving element 21b, and the differential output has a negative value. When the particle D reaches the position x3, the amount of light entering the light receiving element 21 becomes the same again, and the differential output becomes zero. When the particle D comes to the position x4, the amount of light received by the light receiving element 21b is blocked by impurities, and the differential output has a positive value, contrary to the case where the particle D is at the position x2. When the particle D passes through the optical path and reaches the position x5, the light intensity of the light receiving element 21 becomes the same and the differential output becomes zero.

In this way, the particles D block one optical path to each of the two light receiving elements 21, so that the differential output signal outputs waveforms having positive and negative values, and the number of waveforms increases in proportion to the amount of the particles D. . As a result, the contamination level measurement unit 41A measures the amount of particles contained in the liquid, that is, the contamination level.

Further, the contamination level measuring section 41A removes the effects of air bubbles from the differential output signals from the two light receiving elements 21 . Bubbles are output as a larger signal than particles in the differential output signal. The process of removing the effects of air bubbles by the contamination degree measuring unit 41A will be described below.

The contamination level measurement unit 41A acquires the differential output signal output from the adder/subtractor 28, amplifies the differential output signal by a first magnification, and performs full-wave rectification to generate a particle detection signal. Further, the contamination level measurement unit 41A amplifies the differential output signal by a second factor, performs full-wave rectification, and generates an air bubble detection signal.

When bubbles are detected, the crest value of the differential output signal becomes larger than when particles are detected. By setting the second magnification lower than the first magnification, in the bubble detection signal, the particle detection result does not appear as a waveform, and only the bubble detection result appears as a waveform.

The contamination level measurement unit 41A generates an air bubble suppression signal based on the air bubble detection signal. The bubble suppression signal is a signal having two values of Low and High. When the value of the bubble detection signal is not equal to or greater than the threshold, the bubble suppression signal is set to Low, and when the value of the bubble detection signal is equal to or greater than the threshold, the bubble suppression signal is set to High.

When the bubble suppression signal is Low, the contamination level measurement unit 41A integrates the particle detection signal to obtain a contamination level measurement signal. When the bubble suppression signal is High, the contamination degree measurement unit 41A integrates the particle detection signal immediately before the bubble suppression signal becomes High to obtain the contamination degree measurement signal.

Then, the contamination level measurement unit 41A determines the contamination level of the liquid based on the contamination level measurement signal. For example, the contamination level measurement unit 41A determines the contamination level based on the value of the contamination level measurement signal using an evaluation method such as the NAS grading method or the ISO cleanliness level. Then, the contamination level measurement unit 41A outputs the determined contamination level to the output unit 43 . The output unit 43 outputs the contamination degree to the display unit 45 .

Returning to the description of FIG. Since the measuring device 2 is used in an environment of 100° C. or more like the measuring device 1, the substrates 15 and 25 are thermally deformed, the optical axis ax2 moves, and the positions of the light emitting element 11 and the light receiving element 21 shift. put away.

In the present embodiment, since the light emitting element 11 and the light receiving element 21 are in a 1:1 correspondence, even if the positions of the light emitting element 11 and the light receiving element 21 are misaligned, light is emitted from near the front of the light emitting element 11. strong light is incident on the light receiving element 21 .

According to the present embodiment, even if the positions of the light emitting element 11 and the light receiving element 21 are displaced due to thermal deformation, the light emitted from the light emitting element 11 is reliably incident on the light receiving element 21. Contamination degree can be measured reliably.

For example, when light emitted from one light emitting element 11 is received by two light receiving elements 21 as in the conventional measuring apparatus 100 shown in FIG. Arrange the optical axis ax1. The strong light emitted from near the front of the light emitting element 11 does not enter the two light receiving elements 21 , and the light emitted obliquely from the light emitting element 11 enters the light receiving element 21 .

Therefore, if the positions of the light emitting element 11 and the light receiving element 21 are displaced due to thermal deformation, light will not enter one of the two light receiving elements 21 . For example, as shown by the dotted line in FIG. 7, when the two light receiving elements 21 shift to the left side of the paper, light enters the light receiving element 21 on the right side of the paper, but does not enter the light receiving element 21 on the left side of the paper. As a result, the measuring device 100 may not be able to measure the degree of contamination.

On the other hand, in the present embodiment, the light emitted from one light emitting element 11 is received by one light receiving element 21, so that the light emitted from the light emitting element 11 is reliably incident on the light receiving element 21. Therefore, it is possible to prevent a situation in which the degree of contamination cannot be measured due to thermal deformation.

Moreover, according to the present embodiment, since there are two sets of the light emitting element 11 and the light receiving element 21, it is possible to measure the degree of contamination while removing the effects of air bubbles. As a result, the degree of contamination can be measured with high accuracy.

In this embodiment, the two light emitting elements 11 are provided adjacently and the two light receiving elements 21 are provided adjacently. You don't have to. However, in order to measure the degree of contamination by removing the effects of air bubbles from the difference between the outputs of the two light receiving elements 21, it is desirable that the two light emitting elements 11 and the two light receiving elements 21 are adjacent to each other.

<Third Embodiment>
Although the second embodiment of the present invention has two sets of light-emitting elements and light-receiving elements, the number of light-emitting elements and light-receiving elements is not limited to this. The third embodiment of the present invention has three sets of light-emitting elements and light-receiving elements. A measuring device 3 according to the third embodiment will be described below. The same parts as those in the first embodiment or the second embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

FIG. 5 is a cross-sectional view showing the outline of the measuring device 3. As shown in FIG. In addition, in FIG. 5, the hatching which shows a cross section is partially abbreviate|omitted. The measuring device 3 mainly has a light irradiation section 10B, a light receiving section 20B, a housing 30B, and a pipe 39. As shown in FIG.

The light irradiation section 10B mainly has three light emitting elements 11 and a substrate 15 . The light receiving section 20B mainly has three light receiving elements 21 and a substrate 25 . The optical axes ax1 of the light emitting elements 11 respectively overlap the light receiving elements 21 . In FIG. 5, the optical axis ax1 of the light emitting element 11 is aligned with the optical axis ax2 of the light receiving element 21 respectively.

Hereinafter, the most upstream light emitting element 11 and light receiving element 21 are referred to as light emitting element 11a and light receiving element 21a, the central light emitting element 11 and light receiving element 21 are referred to as light emitting element 11b and light receiving element 21b, and the most downstream light emitting element 11 and light receiving element 21 are referred to as light emitting element 11b and light receiving element 21b. The light receiving element 21 is assumed to be a light emitting element 11c and a light receiving element 21c.

The housing 30B mainly has a first housing 31B, a second housing 32, and a third housing 33. As shown in FIG. The first housing 31B has recesses 31d and 31e, a hole 31j provided in the bottom surface of the recess 31d, and a hole 31k provided in the bottom surface of the recess 31e. Two light emitting elements 11 are inserted in the hole 31j. Light emitted from the light emitting element 11 enters the light receiving element 21 through the pipe 39 and the hole 31k.

FIG. 6 is a block diagram showing an outline of the electrical configuration of the measuring device 3. As shown in FIG. The measuring device 3 has a contamination level measuring section 41B, an output section 43, and a display section 45. As shown in FIG. Further, the light irradiation section 10B has a driving circuit 17, and the light receiving section 20B has an amplifier 27 and an adder/subtractor 28. FIG.

A drive circuit 17 drives the three light emitting elements 11 . Each of the three light receiving elements 21 continuously receives the light emitted from the light emitting element 11 and passed through the liquid. Output signals from the two light receiving elements 21 are amplified by amplifiers 27, respectively. The amplifier 27 that amplifies the signal of the light receiving element 21a is referred to as an amplifier 27a, the amplifier 27 that amplifies the signal of the light receiving element 21b is referred to as an amplifier 27b, and the amplifier 27 that amplifies the signal of the light receiving element 21c is referred to as an amplifier 27c.

The output signal of the light receiving element 21a is input to the adder/subtractor 28 after being amplified by the amplifier 27a, the output signal of the light receiving element 21b is input to the adder/subtractor 28 after being amplified by the amplifier 27b, and the output signal of the light receiving element 21c is input to the amplifier. After being amplified by 27c, it is input to the adder/subtractor 28. FIG. The adder/subtractor 28 provides a differential output from the light receiving elements 21a and 21b, a differential output from the light receiving elements 21a and 21c, and a differential output from the light receiving elements 21b and 21c. Since the output signals from the light receiving element 21 and the light receiving element 13 are continuous signals, the differential output of the light receiving element 21 is also a continuous signal.

The differential output is input to the contamination degree measuring section 41B. Based on the differential output of the light receiving element 21, the contamination level measurement unit 41B measures the amount of particles contained in the liquid flowing through the pipe 39. FIG. First, similarly to the contamination degree measurement unit 41A, the contamination degree measurement unit 41B removes the effects of air bubbles based on the differential output signals from the two light receiving elements 21 (for example, the light receiving elements 21a and 21b), and detects the particles. measure the amount of

Further, the contamination level measurement unit 41B detects particles whose particle diameters are within the first range based on the differential output signals from the two light receiving elements (light receiving elements 21a and 21b). 21a, 21c) to detect particles whose particle size falls within the second range. The second range is a range different from the first range. At least one of the two light receiving elements used to detect particles whose particle diameters fall within the first range is different from the two light receiving elements used to detect particles whose particle diameters fall within the second range.

For example, the contamination level measurement unit 41B measures the amount of particles with a diameter of 5 to 15 μm based on the differential output signals from the light receiving elements 21a and 21b, and measures the diameter of particles based on the differential output signals from the light receiving elements 21a and 21c. Measure the amount of particles between 15 and 25 μm.

In the present embodiment, based on the differential output signals from the two light-receiving elements 21, the amount of particles whose particle sizes are included in the first range and the amount of particles whose particle sizes are included in the second range are measured. The degree measuring unit 41B removes the effect of air bubbles and measures the amount of particles having a particle size within each range.

Returning to the description of FIG. The measuring device 3 is provided in a construction machine or the like, and the measuring device 2 is used in an environment of 100 degrees or more during operation of the machine. Under this environment, the substrates 15 and 25 are thermally deformed. The thermal deformation of the substrate 25 causes the optical axis ax2 to move, and the optical axis ax1 and the optical axis ax2 are deviated from each other.

In this embodiment, three sets of light-emitting elements 11 and light-receiving elements 21 are provided, and the light-emitting elements 11 and the light-receiving elements 21 correspond to each other at 1:1. Therefore, the optical axis ax1 of the light-emitting element 11 overlaps the light-receiving element 21 even if the optical axis ax1 and the optical axis ax2 are deviated from each other. Therefore, the light emitted from the light emitting element 11 is reliably incident on the light receiving element 21 .

According to the present embodiment, even if the optical axis ax1 and the optical axis ax2 are deviated due to thermal deformation, the light emitted from the light-emitting element 11 is reliably incident on the light-receiving element 21; The device 1 can reliably measure the degree of contamination.

Moreover, according to the present embodiment, since there are two or more sets of light-emitting elements 11 and light-receiving elements 21, it is possible to measure the degree of contamination while removing the effects of air bubbles.

Moreover, according to this embodiment, since there are two or more sets of the light emitting element 11 and the light receiving element 21, the degree of contamination can be measured for each particle diameter. Depending on the size of the particles contained in the liquid, the source of the particles and the degree of influence of the particles on the hydraulic circuit differ. Therefore, by measuring the degree of contamination for each particle size, it is possible to identify the main cause of the occurrence of contamination and determine the necessity of inspection of the hydraulic system.

In this embodiment, three sets of light-emitting elements 11 and light-receiving elements 21 are provided, but the number of light-emitting elements 11 and light-receiving elements 21 is not limited to this, and may be four or more.

Further, in the present embodiment, particles having a particle diameter within the first range are detected based on the differential output signals from the light receiving elements 21a and 21b, and based on the differential output signals from the light receiving elements 21a and 21c. Although particles having a particle size within the second range are detected, particles having a particle size within a predetermined range may be detected without using the differential output signal. For example, based on the output signal from any one light-receiving element (for example, the light-receiving element 21b), particles whose particle diameters fall within the first range are detected, and particles whose particle diameters fall within the first range are used for detection. Particles having a particle diameter within the second range may be detected based on an output signal from a light receiving element (for example, light receiving element 21c) different from the light receiving element.

In addition, in the present embodiment, in order to detect particles having a particle size within a predetermined range based on the differential output signal, a measuring device is used to measure the amounts of particles having two different particle size ranges. was required to have three light-receiving elements 21, but when measuring the amount of particles in two ranges of different particle diameters based on the output signals from different arbitrary light-receiving elements, the measuring device has two All that is necessary is to have the light receiving element 21 .

Further, in the present embodiment, the three light emitting elements 11 are provided adjacently, and the three light receiving elements 21 are provided adjacently. You don't have to. However, in order to measure the degree of contamination without the effect of air bubbles, it is desirable that the three light emitting elements 11 and the three light receiving elements 21 are adjacent to each other.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and design changes and the like are also included within the scope of the gist of the present invention. . For example, the above embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of the embodiment can be replaced with the configuration of another embodiment, and it is possible to add, delete, or replace the configuration of the embodiment with another configuration. In addition, in the present invention, the term "substantially" is not limited to the case of being exactly the same, but is a concept that includes errors and deformations to the extent that the identity is not lost.

1, 2, 3: measuring devices 10, 10A, 10B: light irradiation units 11, 11a, 11b, 11c: light emitting element 15: substrate 17: drive circuits 20, 20A, 20B: light receiving units 21, 21a, 21b, 21c: Light receiving element 25: substrates 27, 27a, 27b, 27c: amplifier 28: adders/subtractors 30, 30A, 30B: housings 31, 31A, 31B: first housing 31a: hole 31b: hole 31c: female threaded portion 31d: recessed portion 31e : Recesses 31f, 31g, 31h, 31i, 31j, 31k: Hole 32: Second housing 32a: Male threaded portion 32b: Hole 33: Third housing 33a: Male threaded portion 33b: Hole 39: Piping 41, 41A, 41B: Contamination measuring unit 43: output unit 45: display unit 100: measuring device

Claims (5)

a pipe through which a liquid passes, at least a part of which is made of a light-transmitting material;
a light irradiation unit having a first light emitting element that continuously emits light and a first substrate provided with the first light emitting element;
a light-receiving unit having a first light-receiving element that continuously receives light and a second substrate provided with the first light-receiving element;
a housing provided with the first substrate and the second substrate;
a contamination degree measuring unit that measures the degree of contamination of the liquid based on the output signal from the light receiving unit;
with
A hole is provided in the housing, and the pipe is inserted into the hole,
The first light emitting element and the first light receiving element are arranged across the pipe,
The measuring device, wherein the optical axis of the first light emitting element overlaps with the light receiving area of the first light receiving element. The light irradiation unit has at least a second light emitting element that continuously emits light,
The light receiving unit has at least a second light receiving element that continuously receives light,
The second light-emitting element and the second light-receiving element are arranged with the pipe interposed therebetween,
The measuring device according to claim 1, wherein the optical axis of the second light emitting element overlaps the light receiving area of the second light receiving element. The second light emitting element is provided adjacent to the first light emitting element,
The second light receiving element is provided adjacent to the first light receiving element,
3. The contamination degree measurement unit according to claim 2, wherein the contamination degree measurement unit measures the degree of contamination of the liquid based on a difference between an output signal from the first light receiving element and an output signal from the second light receiving element. measuring device. The contamination degree measuring unit detects particles having a particle size within a first range based on the output signal from the first light receiving element, and detects particles having a particle size within the first range based on the output signal from the second light receiving element. 4. A measuring device according to claim 2 or 3, characterized in that particles contained in a second range different from the first range are detected. 5. The measuring device according to any one of claims 1 to 4, wherein a deviation between the optical axis of the first light emitting element and the optical axis of the first light receiving element is 50 [mu]m or less.

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