JPH11142197A - Fluid detection sensor - Google Patents

Abstract

(57) [Problem] To provide a fluid detection sensor which is suitable for detecting a fluid flowing in a pipeline with pulsation and which does not cause mixing of particles into the fluid. SOLUTION: A fluid detection sensor 1 used for detecting a liquid agent flowing with pulsation inside a pipe 11 is formed by using an open base end 5a having a thick portion between an outer peripheral surface and an inner peripheral surface of the conduit 11. The tip 5b which is buried and supported in the pipe and is closed
And a flexible housing member 5 which is disposed as a free end inside and extends perpendicularly to the direction B of the flow of the liquid agent parallel to the extending direction A of the conduit 11. The flexible piezoelectric element 7, which is housed inside the housing member 5 from the base end 5a to the front end 5b and is arranged inside the pipe 11 and whose electric charge changes according to the amount of bending, allows the inside of the pipe 11 to be moved. The piezoelectric element 7 is moved from the upstream side to the downstream side in the flow direction B of the liquid agent in the pipe 11 at a degree corresponding to the flow rate of the liquid agent flowing per unit time.
Is configured to bend together with the housing member 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting the presence or absence of a fluid flowing in a pipeline, and more particularly, to a sensor which is sent into the pipeline by a bellows pump, a diaphragm pump, or the like and causes a pulsation to flow in the pipeline. The present invention relates to a fluid detection sensor suitable for detecting the presence or absence of a fluid.

[0002]

2. Description of the Related Art For example, in a semiconductor manufacturing process, after a mask on a silicon wafer is removed by pickling and then the acid remaining on the silicon wafer is neutralized and washed with a liquid agent, the neutralizing agent and the washing are used. A bellows pump or a diaphragm pump that can maintain a high supply amount accuracy is used to feed the agent onto the silicon wafer.In this type of pump, the pumped fluid has a constant period in a fluid transfer pipe. It has the characteristic of causing pulsation.

[0003] In order to measure a fluid causing pulsation in such a pipeline, conventionally, for example, an area type equation disclosed in Japanese Patent Application Laid-Open No. 7-198433 shown in a sectional view in FIG. A flow meter 21 is used.

In the area type flowmeter 21 described above, a pipe 23 constituting a fluid flow path extends vertically, an annular wall 25 for restricting the flow is provided in the middle thereof, and a frustoconical float 27 is provided. The large-diameter side portion having a larger diameter than the center through-hole 25a of the annular wall 25 is disposed so as to be located above the annular wall 25.
7, a shaft 29 protruding from above and below is supported movably in the axial direction by a thrust bearing 31 in each of the conduits 23 above and below the annular wall 25, and a magnet 33 is embedded inside the float 27, Two magnetic sensors 35 and 37 are arranged outside the pipeline 23.

According to the area type flowmeter 21 having such a configuration, the float 27 moves up and down together with the shaft 29 in accordance with the flow rate of the fluid flowing from the lower part to the upper part in the pipe 23, and Since the magnetic flux generated by the magnet 33 changes, the change in the magnetic flux is detected by the two magnetic sensors 35 and 3.
By detecting the change in the vertical position of the float 27 and detecting the change in the position of the float 27, the presence of the fluid flowing in the pipeline 23 can be detected even if the fluid is accompanied by pulsation.

[0006]

However, in the conventional area type flow meter 21 described above, the float 27
Moves up and down together with the shaft 29, so that the annular wall 25
Contact between the inner peripheral surface of the through hole 25a and the outer peripheral surface of the float 27,
Due to the sliding between the thrust bearing 31 and the shaft 29, fine particles, that is, particles are generated.
3 mixed into the fluid flowing inside, and as described above,
In the case of measuring the flow rate of a neutralizing agent or a cleaning agent sent onto a silicon wafer, particles adhere to the silicon wafer and become defective products that cannot be supplied to the cutting process, thereby deteriorating the yield of semiconductor production. there were.

[0007] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a fluid detection sensor which is suitable for detecting the presence or absence of fluid flowing in a pipeline with pulsation and which does not cause particles to mix into fluid. .

[0008]

According to the first aspect of the present invention, there is provided a fluid detection sensor according to the first aspect of the present invention.
What is claimed is: 1. A fluid detection sensor for detecting a fluid flowing in a pipeline, wherein the fluid detection sensor is disposed inside the pipeline, extends in a direction intersecting with an extending direction of the pipeline, and has a base end provided in the pipeline. And a flexible housing member having a distal end disposed inside the conduit in a non-contact state with the conduit, and a flexible housing member extending from the base end to the distal end of the housing member. And a flexible piezoelectric element whose electric charge changes according to the amount of bending, which is disposed inside the conduit and has a degree according to a flow rate per unit time of a fluid flowing through the conduit. The piezoelectric element is bent together with the housing member from the upstream side to the downstream side of the flow of the fluid in the pipeline.

According to a second aspect of the present invention, in the fluid detection sensor according to the present invention, the spring member is housed in the housing member along the piezoelectric element from the base end to the front end of the housing member. Further, the piezoelectric element bent together with the housing member from the upstream to the downstream by the flow of the fluid in the pipeline, the flow rate of the fluid per unit time of the fluid flowing in the pipeline With the decrease, the spring material returns to the state before being bent by the restoring force.

[0010] According to the fluid detection sensor of the present invention, the flow of the fluid in the pipeline from the upstream side to the downstream side is determined at a degree corresponding to the flow rate of the fluid flowing in the pipeline per unit time. When the pulsating fluid flows through the pipeline and the flow rate of the fluid in the pipeline per unit time changes periodically due to the piezoelectric element flexing with the housing member toward the side, the change occurs. The charge of the piezoelectric element changes according to the flow rate.

Therefore, a phenomenon such as repeated contact and separation of the structure in the pipeline and sliding between the two members does not occur, and as a result, the occurrence of such a phenomenon does not result in a fine structure.
An electric signal with a signal level corresponding to the fluid flow rate in the pipe used to detect the presence or absence of fluid in the pipe without causing the generation of particles or contamination with the fluid. It can be generated by a change in the charge of the piezoelectric element in accordance with the change in.

Further, according to the fluid detection sensor of the present invention, the piezoelectric element which is bent together with the housing member in accordance with the flow rate of the fluid flowing in the pipe per unit time is moved along the piezoelectric element. In addition, due to the restoring force of the spring member housed inside the housing member, the fluid returns to the original state as the flow rate of the fluid flowing in the pipeline decreases per unit time.

For this reason, when the fluid flows in the pipeline with pulsation, the piezoelectric element is repeatedly bent in accordance with the degree of continuation of the flow of the fluid, and the fluid flowing in the pipeline is continuously deformed. Upon detection, it is possible to repeatedly generate an electric signal having an amplitude number corresponding to the continuous time due to a change in the electric charge of the piezoelectric element according to a change in the flow rate of the fluid flowing in the pipeline.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of a fluid detection sensor according to one embodiment of the present invention together with a fluid pipe.
The fluid detection sensor according to the present embodiment, denoted by reference numeral 1, for example, is a liquid agent (not shown) that neutralizes and cleans an acid used for removing a mask on a silicon wafer in a semiconductor manufacturing process.
Is supplied by a bellows pump or a diaphragm pump in a constant amount at a constant period, and is provided in a pipeline 11 flowing inside with pulsation.

The fluid detection sensor 1 includes a signal output unit 3, a housing member 5, a piezoelectric element 7, and a spring member 9.

The signal output section 3 has a substrate 3a attached to the outer peripheral surface of the conduit 11 by a stay or the like. On this substrate 3a, FIG. 2 is a block diagram of the electrical configuration. As shown, a power supply circuit 3b for transforming the power supplied from the power supply 13 and a charge / voltage conversion circuit 3c operated by the transformed power supplied from the power supply circuit 3b;
A filter circuit 3d and a Schmitt trigger circuit 3e are mounted.

In the signal output section 3, a voltage signal having a waveform corresponding to the electric charge of the piezoelectric element 7 generated in the electric charge / voltage conversion circuit 3c is subjected to a Schmitt trigger after a noise component is removed by a filter circuit 3d. The circuit 3e is configured to shape the pulse into a rectangular pulse signal.

As shown in FIG. 1, the housing member 5 has an elongated cylindrical shape with a bottom having a base 5a opened and a tip 5b closed by a flexible material. The base 5a is buried and supported in the thick portion between the outer peripheral surface and the inner peripheral surface of the conduit 11, and the tip 5b of the housing member 5 projects from the inner peripheral surface of the conduit 11 to the inside. The pipe 11 extends in a direction orthogonal to the direction in which the pipe 11
Free end not supported by

The piezoelectric element 7 is formed of a conventionally known bimorph, and is housed in the housing member 5 from the base end 5a to the front end 5b. 9 has a base end 5 a inside the housing member 5.
To the tip 5b.

The housing member 5 is integrated with the piezoelectric element 7 and the spring member 9 by the fluid pressure applied to the peripheral surface of the housing member 5 from the liquid agent in accordance with the flow rate (flow velocity) of the liquid agent flowing in the pipeline 11. 1 from the upstream side (left side in the figure) to the downstream side (right side in the figure) in the direction of flow of the liquid agent in the pipeline 11 indicated by the arrow B in FIG. 5b side is bent, and the fluid pressure applied to the peripheral surface of the housing member 5 from the liquid medicine by the decrease in the flow rate (flow velocity) of the liquid medicine is reduced, so that the spring material 9 returns to the linear posture shown in FIG. It is configured to be.

The piezoelectric element 7 is configured such that the electric charge changes in accordance with the posture of the piezoelectric element 7 integrated with the housing member 5, that is, the degree of bending, and a signal output from the base end 5a of the housing member 5. The charge / voltage conversion circuit 3c connected to the piezoelectric element 7 via the lead wire 7a led to the unit 3 changes the bias voltage applied from the power supply circuit 3b according to the change in the charge of the piezoelectric element 7. , And output to the Schmitt trigger circuit 3e via the filter circuit 3d.

Next, the operation (action) of the fluid detection sensor 1 of the present embodiment configured as described above will be described.

The liquid agent fed by the bellows pump or the diaphragm pump in a constant amount at a constant period flows through the inside of the pipe line 11 with pulsation, and around a peak time of the pulsation, that is, a short time per unit time. As the flow rate approaches the maximum, the fluid pressure applied to the peripheral surface of the housing member 5 from the liquid agent exceeds the force obtained by adding the stiffness of the piezoelectric element 7 and the housing member 5 to the spring force of the spring member 9, thereby increasing the housing force. The member 5 is integrated with the piezoelectric element 7 and the spring member 9, and the tip 5 b side of the housing member 5 bends from the upstream side to the downstream side in the flow direction B of the liquid agent.

After that, after the peak of the pulsation of the liquid agent, the flow rate per hour as seen in a short time decreases,
The fluid pressure applied to the peripheral surface of the housing member 5 from the liquid material becomes lower than the spring force of the spring member 9, and the housing member 5 is integrated with the piezoelectric element 7 and the spring member 9 by the restoring force of the spring member 9, Return to the original posture before bending.

Then, after passing through the state where the flow rate per time as seen in a short time is the smallest, it approaches the peak of the pulsation of the liquid agent flowing inside the pipe line 11 again, and the piezoelectric element 7 and the housing member When the fluid pressure applied to the peripheral surface of the housing member 5 from the liquid agent exceeds the force obtained by adding the rigidity of the housing 5, the housing member 5 bends together with the piezoelectric element 7 and the spring material 9 as described first, and thereafter, After the peak of the pulsation,
The housing member 5 is integrated with the piezoelectric element 7 and the spring member 9 to return to the original posture before bending.

That is, the housing member 5 inside the pipe 11 repeats bending and returning together with the piezoelectric element 7 and the spring material 9 at the same cycle as the pulsation of the liquid agent.

Then, the charge of the piezoelectric element 7 repeatedly increases and decreases in the same cycle as the pulsation of the liquid agent, and the output from the charge / voltage conversion circuit 3c of the signal circuit board 3 to the Schmitt trigger circuit 3e increases and decreases in the same cycle. Circuit 3e
3 (a), an electric signal having a waveform obtained by half-wave rectification of a sine wave with a diode is input, and this is shaped into a waveform by a Schmitt trigger circuit 3e, and the liquid material shown in FIG. 3 (b) is formed. A pulse signal having a rectangular waveform having the same cycle as the pulsation is output from the signal output unit 3 from the Schmitt trigger circuit 3e.

Therefore, by outputting the pulse signal from the Schmitt trigger circuit 3e to the outside of the signal output unit 3, the presence of the liquid agent flowing in the pipe line 11 can be detected by converting it into an electric signal and notified. .

As described above, according to the present embodiment, it is detected whether or not the liquid agent fed by the bellows pump or the diaphragm pump at a constant interval in a constant amount flows through the inside of the pipeline 11 with pulsation. In the fluid detection sensor 1 used for the above, the open base end 5a is buried and supported in the thick portion between the outer peripheral surface and the inner peripheral surface of the pipeline 11, and the closed distal end 5b is free inside the pipeline 11. It is arranged as an end,
A flexible housing member 5 extending perpendicular to the direction B of flow of the liquid agent parallel to the extending direction A of the conduit 11, and the inside of the housing member 5 from the base end 5a to the distal end 5b of the housing member 5; The flexible piezoelectric element 7, which is accommodated in the pipe 11 and is arranged inside the pipe 11 and changes the electric charge according to the amount of bending, has a degree corresponding to the flow rate of the liquid agent flowing through the pipe 11 per unit time. The piezoelectric element 7 is configured to bend together with the housing member 5 from the upstream side to the downstream side in the flow direction B of the liquid agent in the conduit 11.

For this reason, phenomena such as repetition of contact and separation of the structure in the pipeline 11 and sliding between the two members do not occur, and the occurrence of such phenomena does not result in fine particles. While the liquid agent is flowing through the pipe 11 without causing the generation of the liquid or the mixing thereof into the fluid, the electric signal of the signal level corresponding to the flow rate is generated by the electric charge caused by the bending of the piezoelectric element in the pipe 11. Can be caused by the variation of

Further, according to the fluid detection sensor 1 of the present embodiment, the spring member 9 is further accommodated in the accommodation member 5 along the piezoelectric element 7 from the base end 5a to the distal end 5b of the accommodation member 5. When the pulsation of the liquid agent in the pipe 11 reaches the vicinity of the peak and the piezoelectric element 7 bent together with the housing member 5 from the upstream side to the downstream side, the piezoelectric element 7 of the liquid agent flowing through the pipe 11 after the peak of the pulsation. As the flow rate per unit time decreases, the spring member 9 returns to the state before bending due to the restoring force.

For this reason, when the liquid material flows in the pipeline 11 with pulsation, the piezoelectric element 7 is repeatedly bent according to the degree of continuation of the flow of the liquid material, so that the liquid material flowing in the pipeline 11 When continuously detected, an electric signal having an amplitude number corresponding to the continuous time is generated by the fluctuation of the electric charge of the piezoelectric element 7 which repeatedly bends and returns in the same cycle as the pulsation of the liquid medicine in the pipeline 11. Can be.

The configuration described in the present embodiment in which the spring member 9 is further housed inside the housing member 5 along the piezoelectric element 7 provides a necessary restoring force due to the rigidity of the housing member 5 and the piezoelectric element 7. If it can be obtained, it may be omitted.

Further, in the present embodiment, on the assumption that the liquid agent fed by the bellows pump or the diaphragm pump in a fixed amount at a constant period flows through the pipeline 11 with the pulsation, Although a pulse signal capable of notifying the existence by converting it into an electric signal to the outside is notified from the electric signal output from the charge / voltage conversion circuit 3c by the Schmitt trigger circuit 3e, the bending degree of the piezoelectric element 7 is changed by the conduit 11 The signal output unit 3 may be configured so as to be directly proportional to the flow rate of the liquid agent flowing therein, and to directly output an electric signal from which the flow rate can be measured based on the signal level from the charge / voltage conversion circuit 3c. .

That is, if the piezoelectric element 7 is flexed by an amount corresponding to the flow rate of the liquid agent flowing in the conduit 11, the conduit 11
What kind of content is to output the electric signal according to the flow rate of the liquid agent flowing through the inside is arbitrary.

The piezoelectric element 7 is not limited to a bimorph,
It goes without saying that any material can be used as long as the charge changes depending on the degree of bending.

[0038]

As described above, according to the fluid detection sensor of the first aspect of the present invention, there is provided a fluid detection sensor for detecting a fluid flowing in a pipe, wherein the inside of the pipe is And extends in a direction intersecting with the extending direction of the pipeline, a base end is supported by the pipeline, and a distal end is disposed inside the pipeline in a non-contact state with the pipeline. A flexible accommodation member that is accommodated inside the accommodation member from the base end to the distal end of the accommodation member and is disposed inside the conduit, and the electric charge changes according to the amount of bending. A piezoelectric element, and the piezoelectric element moves from the upstream side to the downstream side of the flow of the fluid in the pipeline at a degree corresponding to the flow rate of the fluid flowing in the pipeline per unit time. It was configured to bend with the housing member.

For this reason, the piezoelectric element bends together with the housing member from the upstream side to the downstream side of the flow of the fluid in the pipeline to a degree corresponding to the flow rate of the fluid flowing in the pipeline per unit time. Therefore, when the fluid accompanied by the pulsation flows in the pipeline and the flow rate of the fluid in the pipeline per unit time changes periodically, the electric charge of the piezoelectric element changes according to the changing flow rate.

Therefore, a phenomenon such as repeated contact and separation of a structure in a pipeline and sliding between two members does not occur, and as a result, the occurrence of such a phenomenon is not fine, that is,
An electric signal with a signal level corresponding to the fluid flow rate in the pipe used to detect the presence or absence of fluid in the pipe without causing the generation of particles or contamination with the fluid. Can be generated by a change in the electric charge of the piezoelectric element in accordance with the change in.

Further, according to the fluid detection sensor of the present invention, the housing member is housed in the housing member along the piezoelectric element from the base end to the tip end. Further comprising a spring material, wherein the piezoelectric element bent together with the housing member from the upstream side to the downstream side by the flow of the fluid in the conduit, the per unit time of the fluid flowing in the conduit As the flow rate decreases, the spring member returns to a state before being bent by the restoring force of the spring member.

For this reason, the piezoelectric element bent together with the housing member in accordance with the flow rate of the fluid flowing in the conduit per unit time is applied to the restoring force of the spring material housed inside the housing member along the piezoelectric element. Accordingly, the fluid returns to the original state as the flow rate of the fluid flowing in the pipeline decreases per unit time.

Accordingly, when the fluid flows in the pipeline with pulsation, the piezoelectric element is repeatedly bent according to the degree of continuation of the fluid flow, and the fluid flowing in the pipeline is continuously detected. Then, an electric signal having an amplitude corresponding to the continuous time can be repeatedly generated by a change in the electric charge of the piezoelectric element in accordance with a change in the flow rate of the fluid flowing in the pipeline.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a fluid detection sensor according to an embodiment of the present invention, together with a fluid pipeline.

FIG. 2 is a block diagram illustrating an electrical configuration of a signal output unit in FIG. 1;

3A is a waveform diagram of an electric signal input to the Schmitt trigger circuit of FIG. 2, and FIG. 3B is a waveform diagram of an electric signal output from the Schmitt trigger circuit.

FIG. 4 is a sectional view of an area type flow meter according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluid detection sensor 5 Housing member 5a Housing member base end 5b Peripheral member distal end 7 Piezoelectric element 9 Spring material 11 Pipe line A Pipe extending direction

Claims (2)

[Claims] 1. A fluid detection sensor used for detecting a fluid flowing in a pipeline, wherein the fluid detection sensor is disposed inside the pipeline, extends in a direction intersecting with an extension direction of the pipeline, and has a base. A flexible accommodating member having an end supported by the conduit and a distal end disposed inside the conduit in a non-contact state with the conduit, and extending from the base end to the distal end of the accommodating member. A flexible piezoelectric element that is housed inside the housing member and is arranged inside the conduit, and changes the charge according to the amount of bending, and the flow rate of the fluid flowing through the conduit per unit time Wherein the piezoelectric element bends together with the housing member from the upstream side to the downstream side of the flow of the fluid in the pipeline at a degree corresponding to the following. And a spring member that is housed inside the housing member along the piezoelectric element from the base end to the front end of the housing member, and is provided by a flow of a fluid in the pipe. The piezoelectric element bent together with the housing member from the upstream side to the downstream side before bending due to the restoring force of the spring material with a decrease in the flow rate per unit time of the fluid flowing in the pipeline. The fluid detection sensor according to claim 1, wherein the fluid detection sensor returns to the state of (1).