Particle detection device

Abstract

To reduce power consumption.SOLUTION: A primary-side channel 21 is connected with atmospheric air, which may generate a constant flow of compressed fluid from a supply channel 16 in a branch channel 20. A pressure reduction part 23 reduces a pressure of the compressed fluid flowing in the primary-side channel 21. Upon introduction of a part of the compressed fluid flowing in an upstream-side channel 24 through an introduction channel 31, an ejector 28 draws toward an optical sensor 30, the compressed fluid flowing in the primary-side channel 21 after the pressure is reduced by the pressure reduction part 23. This allows the pressure-reduced compressed fluid to flow by a constant flow rate toward the optical sensor 30. Consequently, unlike the prior art, a pump is not required to be installed on a downstream side of the optical sensor 30 in the direction of flow of the compressed fluid, which may prevent occurrence of a problem that driving the pump leads to power consumption.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0003]

[0001] The present invention relates to a particle detection device for detecting particles contained in a compressed fluid.

Background Art

[0002] The particle detection device includes a branch flow path that branches from a supply flow path for supplying compressed fluid from a fluid supply source to a fluid pressure device. A part of the compressed fluid flowing through the supply flow path flows through the branch flow path. The particle detection device also includes an optical sensor. The optical sensor is provided in the branch flow path. The optical sensor detects particles contained in the compressed fluid flowing through the branch flow path.

[0003] Here, in order to flow a fixed flow rate of the decompressed compressed fluid through the optical sensor, it is known to install a pump, for example as in Patent Document 1, on the downstream side of the optical sensor in the flow direction of the compressed fluid. The pump draws in the compressed fluid toward the optical sensor so that a fixed flow rate of the decompressed compressed fluid flows through the optical sensor. By driving the pump in this way, a fixed flow rate of the decompressed compressed fluid flows through the optical sensor, and particles contained in the compressed fluid are accurately detected by the optical sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, driving the pump consumes electric power, so there is a problem that the power consumption in the particle detection device increases.

Means for Solving the Problems

[0006] A particle detection device that solves the above problems comprises a supply channel that supplies compressed fluid from a fluid supply source to a fluid pressure device, a branch channel through which a portion of the compressed fluid flowing in the supply channel flows, and an optical sensor provided in the branch channel that detects particles contained in the compressed fluid flowing in the branch channel, wherein the branch channel has a primary side channel located upstream of the optical sensor in the direction of the flow of the compressed fluid, and a secondary side channel located downstream of the optical sensor in the direction of the flow of the compressed fluid, and the primary side flow The passage is connected to the atmosphere, the primary side passage is provided with a pressure reducing section for reducing the pressure of the compressed fluid flowing through the primary side passage, and the secondary side passage is provided with an ejector, which includes an introduction passage for introducing a portion of the compressed fluid flowing through the upstream side passage, located upstream of the pressure reducing section in the primary side passage in the direction of the compressed fluid flow, into the ejector, and the ejector draws the compressed fluid flowing through the primary side passage, which has been reduced in pressure by the pressure reducing section, toward the optical sensor by introducing a portion of the compressed fluid flowing through the upstream side passage via the introduction passage.

[0007] In the particle detection device described above, the introduction channel is preferably provided with a flow rate adjustment unit that adjusts the flow rate of the compressed fluid introduced into the ejector. The particle detection device described above is preferably equipped with an on / off valve that opens when a particle is detected, thereby allowing the flow of compressed fluid from the supply channel to the branch channel. [Effects of the Invention]

[0008] According to this invention, power consumption can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram illustrating a particle detection device in an embodiment. [Modes for carrying out the invention]

[0010] Below, one embodiment of the particle detection device will be described with reference to Figure 1. <Configuration of particle detection device 10> As shown in Figure 1, the particle detection device 10 includes a body 11. The body 11 is made of resin or metal. The body 11 has an upstream port 11a and a downstream port 11b.

[0011] Upstream piping 12 is connected to upstream port 11a. Downstream piping 13 is connected to downstream port 11b. Upstream piping 12 is connected to fluid supply source 14. Therefore, upstream piping 12 connects fluid supply source 14 to upstream port 11a. Downstream piping 13 is connected to fluid pressure equipment 15. Therefore, downstream piping 13 connects downstream port 11b to fluid pressure equipment 15. Fluid supply source 14 supplies compressed fluid to fluid pressure equipment 15. The compressed fluid is, for example, compressed air.

[0012] The body 11 has a connecting channel 11c. The connecting channel 11c is formed inside the body 11. The connecting channel 11c connects the upstream port 11a and the downstream port 11b. Compressed fluid from the fluid supply source 14 is supplied to the fluid pressure device 15 via the upstream piping 12, the upstream port 11a, the connecting channel 11c, the downstream port 11b, and the downstream piping 13. Therefore, the upstream piping 12, the upstream port 11a, the connecting channel 11c, the downstream port 11b, and the downstream piping 13 constitute a supply channel 16 that supplies compressed fluid from the fluid supply source 14 to the fluid pressure device 15.

[0013] The particle detection device 10 is equipped with a branch channel 20. The branch channel 20 is formed inside the body 11. The branch channel 20 branches off from the connecting channel 11c. Therefore, the branch channel 20 branches off from the supply channel 16. A portion of the compressed fluid flowing through the connecting channel 11c flows through the branch channel 20. Therefore, a portion of the compressed fluid flowing through the supply channel 16 flows through the branch channel 20.

[0014] The particle detection device 10 is equipped with an optical sensor 30. The optical sensor 30 is built into the body 11. The optical sensor 30 is installed in the branch channel 20. The optical sensor 30 detects particles contained in the compressed fluid flowing through the branch channel 20. The optical sensor 30 has a light-emitting unit and a light-receiving unit (not shown). The optical sensor 30 is configured such that light emitted from the light-emitting unit irradiates the compressed fluid flowing through the branch channel 20, and scattered light, which is light irradiated by the compressed fluid and reflected by particles contained in the compressed fluid, is received by the light-receiving unit. The optical sensor 30 detects particles contained in the compressed fluid flowing through the branch channel 20 based on the light intensity level of the light received by the light-receiving unit.

[0015] The branched channel 20 has a primary channel 21 and a secondary channel 22. The primary channel 21 is the portion of the branched channel 20 located upstream of the optical sensor 30 in the direction of compressed fluid flow. The secondary channel 22 is the portion of the branched channel 20 located downstream of the optical sensor 30 in the direction of compressed fluid flow.

[0016] The primary side flow path 21 has a first flow path 21a and a second flow path 21b. The first end of the first flow path 21a is connected to the connecting flow path 11c. Therefore, the first end of the first flow path 21a is connected to the supply flow path 16. The second end of the first flow path 21a is connected to the atmosphere. Therefore, the primary side flow path 21 is connected to the atmosphere.

[0017] The first end of the second channel 21b is connected to the first channel 21a. The second end of the second channel 21b is connected to the optical sensor 30. A portion of the compressed fluid flowing through the first channel 21a flows into the second channel 21b. The compressed fluid that flows from the first channel 21a into the second channel 21b flows towards the optical sensor 30.

[0018] The first flow path 21a is provided with a pressure reducing section 23. Therefore, the primary side flow path 21 is provided with the pressure reducing section 23. The pressure reducing section 23 is provided at a portion located upstream of the portion where the first end of the second flow path 21b in the first flow path 21a is connected in the flow direction of the compressed fluid. The pressure reducing section 23 reduces the pressure of the compressed fluid flowing through the primary side flow path 21. The pressure reducing section 23 is, for example, a variable orifice.

[0019] The first flow path 21a has an upstream side flow path 24. The upstream side flow path 24 is a portion located upstream of the pressure reducing section 23 in the first flow path 21a in the flow direction of the compressed fluid. Therefore, the upstream side flow path 24 is a portion located upstream of the pressure reducing section 23 in the primary side flow path 21 in the flow direction of the compressed fluid. The first end of the upstream side flow path 24 is connected to the connecting flow path 11c. Therefore, the first end of the upstream side flow path 24 is connected to the supply flow path 16. The first end of the upstream side flow path 24 is also the first end of the first flow path 21a. The second end of the upstream side flow path 24 is connected to the pressure reducing section 23.

[0020] The particle detection device 10 includes a pressure sensor 25. The pressure sensor 25 detects the pressure of the compressed fluid flowing through the upstream side flow path 24. Therefore, the pressure sensor 25 detects the pressure of a portion located upstream of the pressure reducing section 23 in the primary side flow path 21 in the flow direction of the compressed fluid.

[0021] The particle detection device 10 includes an on-off valve 26. The on-off valve 26 is provided at a portion located upstream of the pressure sensor 25 in the upstream side flow path 24 in the flow direction of the compressed fluid. Therefore, the on-off valve 26 is provided in the branch flow path 20. The on-off valve 26 allows the flow of the compressed fluid from the supply flow path 16 to the branch flow path 20 by opening the valve when detecting particles. The on-off valve 26 is, for example, an electromagnetic valve.

[0022] The first end of the secondary side flow path 22 is connected to the optical sensor 30. The second end of the secondary side flow path 22 is connected to the atmosphere. And the compressed fluid that has passed through the optical sensor 30 is released to the atmosphere via the secondary side flow path 22.

[0023] The particle detection device 10 includes a flow rate sensor 27. The flow rate sensor 27 is provided in the secondary flow path 22. The flow rate sensor 27 detects the flow rate of the compressed fluid flowing through the secondary flow path 22. Therefore, the flow rate sensor 27 detects the flow rate of the compressed fluid flowing through the optical sensor 30.

[0024] An ejector 28 is provided in the secondary flow path 22. The ejector 28 is provided at a portion located on the downstream side in the flow direction of the compressed fluid from the flow rate sensor 27 in the secondary flow path 22.

[0025] The particle detection device 10 includes an introduction flow path 31. The introduction flow path 31 is formed inside the body 11. The first end of the introduction flow path 31 is connected to a portion between the pressure sensor 25 and the decompression unit 23 in the upstream flow path 24. The second end of the introduction flow path 31 is connected to the ejector 28. The introduction flow path 31 introduces a part of the compressed fluid flowing through the upstream flow path 24 into the ejector 28.

[0026] When a part of the compressed fluid flowing through the upstream flow path 24 is introduced through the introduction flow path 31, the ejector 28 draws in the compressed fluid flowing through the primary flow path 21 after being decompressed by the decompression unit 23 toward the optical sensor 30.

[0027] A flow rate adjustment unit 32 is provided in the introduction flow path 31. The flow rate adjustment unit 32 adjusts the flow rate of the compressed fluid introduced into the ejector 28. The flow rate adjustment unit 32 is, for example, a variable orifice.

[0028] <Controller 40> The particle detection device 10 includes a controller 40. The controller 40 is electrically connected to an external control device 41 such as a programmable logic controller (PLC). Power is supplied to the controller 40 from the external control device 41.

[0029] The controller 40 is electrically connected to the optical sensor 30. For example, information regarding the light intensity level of the light received by the light receiving unit of the optical sensor 30 is transmitted to the controller 40. Based on the information regarding the light intensity level transmitted from the light receiving unit, the controller 40 detects the particle size, quantity, etc. The controller 40 then transmits the detection information, such as the particle size and quantity detected by the controller 40, to an external control device 41. The external control device 41 monitors the detection information, such as the particle size and quantity, transmitted from the controller 40.

[0030] The controller 40 is electrically connected to the pressure sensor 25. The controller 40 receives information about the pressure detected by the pressure sensor 25. The controller 40 is electrically connected to the pressure reduction unit 23. Based on the pressure information transmitted from the pressure sensor 25, the controller 40 controls the opening of the pressure reduction unit 23 so that the pressure of the compressed fluid that has passed through the pressure reduction unit 23 is reduced to atmospheric pressure. The pressure of the compressed fluid that has been reduced by the pressure reduction unit 23 and is flowing through the primary side flow path 21 is slightly higher than atmospheric pressure.

[0031] The controller 40 is electrically connected to the flow sensor 27. Information regarding the flow rate detected by the flow sensor 27 is transmitted to the controller 40. The controller 40 is electrically connected to the flow rate adjustment unit 32. The controller 40 then controls the opening degree of the flow rate adjustment unit 32 based on the flow rate information transmitted from the flow sensor 27.

[0032] For example, if the flow rate detected by the flow sensor 27 is greater than a predetermined flow rate, the controller 40 reduces the opening of the flow rate adjustment unit 32. On the other hand, for example, if the flow rate detected by the flow sensor 27 is less than a predetermined flow rate, the controller 40 increases the opening of the flow rate adjustment unit 32.

[0033] The smaller the opening of the flow rate adjustment unit 32, the less compressed fluid is introduced to the ejector 28 from the upstream flow path 24 via the introduction flow path 31. This reduces the flow rate of compressed fluid drawn from the primary flow path 21 towards the optical sensor 30 by the ejector 28. On the other hand, the larger the opening of the flow rate adjustment unit 32, the more compressed fluid is introduced to the ejector 28 from the upstream flow path 24 via the introduction flow path 31. This increases the flow rate of compressed fluid drawn from the primary flow path 21 towards the optical sensor 30 by the ejector 28. Therefore, the flow rate adjustment unit 32 adjusts the flow rate of compressed fluid drawn from the primary flow path 21 towards the optical sensor 30 by the ejector 28. The opening of the flow rate adjustment unit 32 is adjusted by the controller 40 so that a constant flow rate of compressed fluid flows through the primary flow path 21 after depressurization to the optical sensor 30.

[0034] The controller 40 is electrically connected to the on-off valve 26. The controller 40 receives information regarding the operation of the on-off valve 26 from the external control device 41. For example, when the external control device 41 sends a command to the controller 40 to open the on-off valve 26, the controller 40 controls the operation of the on-off valve 26 so that it opens. On the other hand, when the external control device 41 sends a command to the controller 40 to close the on-off valve 26, the controller 40 controls the operation of the on-off valve 26 so that it closes.

[0035] [Effect of the Embodiment] Next, the operation of this embodiment will be described. Compressed fluid from the fluid supply source 14 is supplied to the fluid pressure device 15 via the upstream piping 12, upstream port 11a, connecting channel 11c, downstream port 11b, and downstream piping 13. When an operator operates the external control device 41 and sends command information to the controller 40 to open the on-off valve 26, the controller 40 controls the drive of the on-off valve 26 so that the on-off valve 26 opens. As a result, the on-off valve 26 opens.

[0036] Since the primary flow path 21 is connected to the atmosphere, compressed fluid from the supply flow path 16 can always flow into the branch flow path 20. Therefore, when the on-off valve 26 is opened, compressed fluid from the supply flow path 16 can always flow into the branch flow path 20. The compressed fluid that flows from the supply flow path 16 into the upstream flow path 24 of the branch flow path 20 passes through the on-off valve 26 and flows towards the pressure reduction section 23. The pressure sensor 25 detects the pressure of the compressed fluid flowing in the upstream flow path 24. The controller 40 controls the opening degree of the pressure reduction section 23 based on the pressure information transmitted from the pressure sensor 25. The pressure reduction section 23 reduces the pressure of the compressed fluid flowing in the primary flow path 21.

[0037] A portion of the compressed fluid flowing through the upstream channel 24 flows into the introduction channel 31. The ejector 28 then draws the compressed fluid flowing through the primary channel 21, which has been depressurized by the depressurization unit 23, toward the optical sensor 30, as a portion of the compressed fluid flowing through the upstream channel 24 is introduced through the introduction channel 31. The flow sensor 27 detects the flow rate of the compressed fluid flowing through the secondary channel 22. The controller 40 controls the opening of the flow adjustment unit 32 based on the flow rate information transmitted from the flow sensor 27. As a result, a constant flow rate of depressurized compressed fluid flows to the optical sensor 30. The optical sensor 30 then detects particles contained in the compressed fluid.

[0038] The compressed fluid that passes through the optical sensor 30 and flows out into the secondary channel 22 passes through the ejector 28 and is then released into the atmosphere. Similarly, the compressed fluid introduced into the ejector 28 via the introduction channel 31 passes through the ejector 28, flows out into the secondary channel 22, and is released into the atmosphere.

[0039] When an operator operates the external control device 41 and sends a command to the controller 40 to close the on-off valve 26, the controller 40 controls the drive of the on-off valve 26 so that it closes. As a result, the on-off valve 26 closes, and a portion of the compressed fluid flowing through the supply channel 16 is prevented from flowing into the branch channel 20. The compressed fluid from the fluid supply source 14 is then supplied entirely to the fluid pressure device 15 via the upstream piping 12, upstream port 11a, connecting channel 11c, downstream port 11b, and downstream piping 13.

[0040] [Effects of the Embodiment] The above embodiment can be achieved to obtain the following effects. (1) Since the primary channel 21 is connected to the atmosphere, a flow of compressed fluid from the supply channel 16 can always occur in the branch channel 20. Furthermore, the depressurization unit 23 depressurizes the compressed fluid flowing in the primary channel 21. The ejector 28 then draws the compressed fluid flowing in the primary channel 21, which has been depressurized by the depressurization unit 23, toward the optical sensor 30 by introducing a portion of the compressed fluid flowing in the upstream channel 24 through the introduction channel 31. This allows a constant flow rate of depressurized compressed fluid to be supplied to the optical sensor 30. Therefore, unlike conventional technology, there is no need to install a pump downstream of the optical sensor 30 in the direction of compressed fluid flow, thus avoiding the problem of power consumption due to driving a pump. Thus, power consumption in the particle detection device 10 can be reduced.

[0041] (2) The introduction channel 31 is provided with a flow rate adjustment unit 32 that adjusts the flow rate of the compressed fluid introduced into the ejector 28. With this, the flow rate of the compressed fluid introduced into the ejector 28 from the upstream channel 24 via the introduction channel 31 can be adjusted by the flow rate adjustment unit 32, thereby adjusting the flow rate of the compressed fluid drawn from the primary channel 21 towards the optical sensor 30 by the ejector 28. Therefore, it is possible to easily adjust the compressed fluid flowing through the primary channel 21 after depressurization so that a constant flow rate flows to the optical sensor 30. As a result, particles contained in the compressed fluid can be detected accurately by the optical sensor 30.

[0042] (3) The particle detection device 10 is equipped with an on-off valve 26 that opens when particles are detected, allowing the flow of compressed fluid from the supply channel 16 to the branch channel 20. With this, a flow of compressed fluid from the supply channel 16 to the branch channel 20 can always be generated only when the on-off valve 26 is open. Therefore, even when it is not necessary to detect particles contained in the compressed fluid, no part of the compressed fluid flowing through the supply channel 16 will flow into the branch channel 20, thus avoiding the wasteful consumption of compressed fluid from the fluid supply source 14.

[0043] (4) Unlike conventional technology, there is no need to install the pump downstream of the optical sensor 30 in the direction of the compressed fluid flow. This avoids problems such as the optical sensor 30 being unable to accurately detect particles due to pump vibration or noise generation from the pump.

[0044] (5) The flow sensor 27 is installed in the secondary flow path 22. This prevents dust and other particles generated from the flow sensor 27 from flowing into the optical sensor 30, as would occur if the flow sensor 27 were installed in the second flow path 21b of the primary flow path 21. Therefore, particles contained in the compressed fluid can be accurately detected by the optical sensor 30.

[0045] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0046] In this embodiment, the particle detection device 10 may be configured such that the flow rate adjustment unit 32 is not provided in the introduction channel 31. In this embodiment, the particle detection device 10 may be configured without an on-off valve 26.

[0047] In this embodiment, the on-off valve 26 is not limited to a solenoid valve. For example, the on-off valve 26 may be a manual valve. In one embodiment, for example, a regulator may be provided as a pressure reducing unit in the upstream flow path 24.

[0048] In this embodiment, the flow sensor 27 may be provided in the second flow path 21b of the primary flow path 21. In one embodiment, the optical sensor 30 may be configured such that, for example, light emitted from a light-emitting unit is received by a light-receiving unit, and the light intensity level of the light received by the light-receiving unit changes when the light emitted from the light-emitting unit is blocked by particles contained in the compressed fluid.

[0049] In this embodiment, it is not necessary to reduce the pressure of the compressed fluid that has passed through the pressure reduction section 23 to atmospheric pressure. In short, it is sufficient that the pressure of the compressed fluid that has passed through the pressure reduction section 23 is reduced to a pressure at which particles can be detected by the optical sensor 30. [Explanation of symbols]

[0050] 10...Particle detection device, 14...Fluid supply source, 15...Fluid pressure equipment, 16...Supply channel, 20...Branch channel, 21...Primary channel, 22...Secondary channel, 23...Depressurization section, 24...Upstream channel, 26...On / off valve, 28...Ejector, 30...Optical sensor, 31...Inlet channel, 32...Flow rate adjustment section.

Claims

1. A supply channel that supplies compressed fluid from a fluid supply source to a fluid pressure device branches off from the supply channel, and a branch channel through which a portion of the compressed fluid flowing in the supply channel flows, A particle detection device comprising: an optical sensor provided in the branch channel for detecting particles contained in the compressed fluid flowing through the branch channel, The aforementioned branch channel is A primary flow path located upstream of the optical sensor in the flow direction of the compressed fluid, It has a secondary flow path located downstream of the optical sensor in the flow direction of the compressed fluid, The primary side channel has a first channel and a second channel, The first end of the first channel is connected to the supply channel, and the second end of the first channel is connected to the atmosphere. The first channel is provided with a pressure reduction section that reduces the pressure of the compressed fluid flowing through the primary channel. The first end of the second channel is connected to the first channel, and the second end of the second channel is connected to the optical sensor. The first end of the secondary side channel is connected to the optical sensor, and the second end of the secondary side channel is connected to the atmosphere at a different position from the second end of the first channel. An ejector is provided in the aforementioned secondary side flow path. The system includes an introduction channel that introduces a portion of the compressed fluid flowing through an upstream channel located upstream of the pressure reduction section in the primary channel in the direction of the compressed fluid flow, into the ejector. The particle detection device is characterized in that the ejector draws the compressed fluid flowing through the primary channel, which has been depressurized by the depressurization unit, toward the optical sensor by introducing a portion of the compressed fluid flowing through the upstream channel through the introduction channel, and the fluid that has passed through the optical sensor and flowed out into the secondary channel passes through the ejector and is then released into the atmosphere.

2. The particle detection device according to claim 1, characterized in that a flow sensor is provided between the optical sensor and the ejector in the secondary flow path.

3. The particle detection device according to claim 1 or 2, characterized in that the introduction channel is provided with a flow rate adjustment unit for adjusting the flow rate of the compressed fluid introduced into the ejector.

4. The particle detection device according to claim 1 or 2, further comprising an on / off valve that opens when detecting the aforementioned particles to allow the flow of compressed fluid from the supply channel to the branch channel.

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