JPH076488Y2 - Laminar proportional amplification element flow meter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminar flow proportional amplification element flow meter, and more particularly to a laminar flow proportional amplification element to oscillate a fluid vibration, the fluid vibration being proportional to the flow rate. Relates to the structure of a flow meter using

Prior art Laminar flow proportional amplification element shown in FIG. 6 (hereinafter referred to as LPA)
As is well known, a plate-like body having a flow passage in a closed curve flows into the fluid supply port 1, and the fluid ejected from the supply nozzle 10 is deflected by the momentum of the control flow introduced from the control port 4 or 5. Is output from the output port 3 or 2 divided by the splitter 11 as a fluid pressure amplified in proportion to the control flow pressure in a predetermined range. The control energy is small and the dynamic range is wide.
Since it has a characteristic of high pressure gain, it is also used in many fluid devices. There is an oscillator that uses the amplification effect of LPA, and the oscillator has an output port 2
And the control port 4 are communicated with each other, and a single feedback oscillator that vibrates sustainably at a frequency at which the one-cycle transmission phase delay is πrad, and the output port 3 and the control port 5 are communicated in addition to the communication path of the single feedback oscillator. The oscillating frequency in these oscillators is proportional to the transmission velocity depending on the jet velocity of the supply nozzle 10. That is, in a relationship where the jet velocity and the flow rate are proportional, the oscillation frequency is proportional to the flow rate, so it is used as an LPA flow meter, and the fluid flowing from the supply nozzle 10 is fed from the downstream vents 6, 7 and the upstream vents 8, 9. It has a method of leakage. However, as described above, the LPA flow meter has a proportional relationship between the flow rate and the oscillation frequency in the range where the jet velocity from the supply nozzle 10 is proportional to the flow rate, that is, in the Reynolds number range where the flow velocity distribution is constant, The proportional relationship is a matter of concern. Further, the LPA is a plate having a uniform thickness formed by removing the flow path portion shown in FIG. 5, and in use, it is sandwiched from both sides by a cover plate having a return path in the oscillator (not shown). Since it is a laminated body, the proportional relationship is further deteriorated because the jet velocity is affected by the viscosity of the cover plate surface and the like. In order to solve this problem, improve the proportional relationship, and expand the measurement range, as shown in the circuit diagram of Fig. 7, three stages of LPA are connected in cascade to control the output of the last stage of the first stage. Some have negative feedback to the port.

In FIG. 7, three-stage LPAs are designated as A, B, and C, and suffixes are attached to each. According to FIG. 6, the suffix has an outflow supply port of 1, an output port of 2, 3 and a control port of 4, 5, respectively. Fluid is fluid supply port A1, B
1 and C1 flow in parallel, one output port A3, B3, C3 to control port B5, C5, A5 respectively, the other output port A2, B
2, C2 form circulation paths communicating with control ports B4, C4, and A4, respectively, and upstream and upstream vents A6-9, B6
.About.9 and C6.about.9 merge and flow out. In such a circulation path, the loop transfer gain increases to the third power per stage, while the pressure signal transmission delay due to the jet increases three times, so the oscillation frequency decreases to about 1/3, and as a result, the jet flow increases. The effect of the phase delay due to the interference band and the feedback loop is relatively reduced. Therefore, the linearity of the oscillation frequency-flow rate characteristic is improved, the upper limit of measurement is expanded about three times with respect to the flow velocity, and the lower limit flow region is expanded similarly.

FIG. 8 is a diagram showing a specific example of the above-mentioned LPA flowmeter, in which a to k are plate-shaped members of equal size, a and k are cover plates, a is the uppermost part, and k is the lowermost part. Place and LPA A, B, C
Of the auxiliary plates c, f, i and the return plates 2-4, 3-5 for forming the flow passages according to the circuit diagram of FIG. g and j are alternately laminated and integrally fixed by screws or the like through screw holes formed at four corners of each plate-like body (not shown). Incidentally, A4 and A5 shown in the figure represent through holes for the fluids returning from the output ports C2 and C3 of the LPA-C to the control ports A4 and A5 of the LPA-A, respectively. The fluid to be measured flows in from the through hole 1 of the cover plate a and flows out from the vents 6 to 9 of the cover plates a and k.

Problems of Prior Art The above-mentioned LPA flowmeter is a stack of plate states, and it is possible to configure a small flowmeter. However, in the LPA flowmeter, the flow passage cross-sectional area of the return flow passage, the output ports 2 and 3,
Relationship with the output flow passage cross-sectional area formed by the splitter 11,
That is, since the flow path impedance ratio has a great influence on the linear range of flow rate-device difference, the optimum flow path cross-sectional area is experimentally obtained. According to an experiment by the applicant, it has been confirmed that the linear range is widest when the cross-sectional area of the return flow passage is set to about 4 times the cross-sectional area of the output flow passage. It is difficult to set the path impedance ratio.
In the stack of plate-shaped bodies shown in the figure, when formed so as to circulate in the return flow path, LPA-C from output ports 2 and 3 of LPA-C
It is impossible to make the flow path impedance of the return flow path to control ports 4,5 of A the same as the flow path impedance of the return flow path from LPA-A to LPA-B and LPA-B to LPA-C. Since the symmetry cannot be maintained, a flowmeter with sufficiently satisfactory characteristics could not be obtained.

Means for Solving Problems This invention was made in order to solve the above problems. Instead of laminating LPA in a plane to form a three-dimensional structure, the LPA is arranged in a three-dimensional structure and each function is The characteristics of each flow path such as inflow, outflow flow path, or return flow path between LPAs having the same characteristics are made to be the same for all LPAs, and the flow rate range is wide without any special machining method. The purpose of the present invention is to provide an excellent LPA flowmeter easily and inexpensively, and the gist thereof is an odd-numbered n-square tube, which has a main flow path that penetrates from each inner wall surface to the outer wall surface. , A base member in which a return flow path penetrating the outer wall surface with each apex angle sandwiched is bored, plate-shaped first, second, ..., Nth laminar flow proportional amplification elements, and the laminar flow proportional amplification A cover plate that is welded and laminated on one surface of the element, and the other surface of each laminar flow proportional amplification element is attached to the outer wall of the base member. , The fluid supply port of each laminar flow proportional amplification element is communicated with the main flow path, and the first, second, ..., Nth control ports are sequentially connected through the return flow path to the nth, first ,. , Nth
A main body that forms a circulation path communicating with the output port of -1 and that generates fluid vibration proportional to the flow rate of the fluid that flows in from the main flow path and flows out from the vent, and a detection unit that detects the fluid vibration It is a laminar proportional amplification element flowmeter.

Example FIG. 1 and FIG. 2 show a main body 100 which is an essential part of an LPA flow meter. FIG. 1 is a developed view, and FIG. 2 (a) is a side view of the main body 100. 2B is a sectional view taken along the line X--X in FIG. 2A, in which the main body 100 shown is formed according to the circuit diagram of FIG. 7, and the reference numerals relating to LPA are given accordingly. In the present invention, the body may be a cylindrical body having an odd number of n-gons, but here, it is an equilateral triangle. The base member 12 is supplied to each LP from the liquid supply source.
A vacant chamber 13 communicating with the LPA-A, B, C which is a fluid supply port of A through a main flow path is provided. Main channels are 14A, 14B, 14C
Indicate. Each LPA connects the fluid supply ports A1, B1, C1 to the main passage 1
A line connecting the supply nozzle 10 and the splitter 11 is formed on each side surface of the main body 100 so as to communicate with 4A, 14B, and 14C.
The cover plates AC, BC, CC are covered in the direction orthogonal to the axis of and are pressed against each other with screws 18 or the like. Cover plate A
Each of C, BC, and CC has a through hole that opens at the upstream and downstream vents of LPA, forming an outlet. Cover plate AC6-9 for AC, BC6-9 for BC, CC6 for CC respectively
It is shown by CC6-9. Each LPA-shown in the exploded view of FIG.
The return path communicating from the output port of this stage of A, B, C to the control port of the next stage is a through hole opened on both sides across each apex angle of the base member 12, LPA-A, LPA between B
-Return path between output port A2 of A and control port B4 of LPA-B is 15A, and return path between output port A3 of LPA-A and control port B5 of LPA-B is 15B. , C between 16A and 16B, and LPA-C and A between 17A and 17B. As a result, the main flow paths 14A, 14B, 14C have the same path length, and all the return paths 15A,
B, 16A, B, 17A, B can also form a circulation path having the same length. The operation of the main body 100 described above forms the fluid oscillation circuit shown in FIG. 7 by allowing the fluid to flow into the inner chamber 13 to continue the oscillation, and the fluid other than the return flow from the vent to the respective covers. Plate outlet AC6-9, BC6-9, CC
It flows out of the main body 100 through 6 to 9. Since the circuit impedance in the fluid oscillation circuit can be made completely equal, the amplification characteristics of the respective stages A to C are also equal and stable, and since the multistage amplification circuit is used, the flow rate range is expanded. In FIG. 1, the equilateral triangular base member 12 is used, but an n-gon base member may be used, and n is an odd number of n> 2, and the amplification gain is increased by increasing the number of stages, so that the flow rate range can be further expanded. . When the main body part 100 is used as a practical flow meter, the flow pipes 20 other than the inner chamber 13 are introduced into the flow pipe 20 shown in FIG. The inside is sealed and discharged from the space formed by the flow tube 20 and the main body 100. FIG. 3 shows an example thereof. FIG. 3 (a) is a sectional view taken along the line YY in FIG. 3 (b), and FIGS. 3 (b) and 3 (c) are respectively a third view. Each arrow in Figure (a) X-
In the X, ZZ cross-sectional view, the flow pipe 20 has flanges 28 at both ends, and the flow inlet 21 is an opening that seals the outside of the base member 12 in the same shape as the front opening of the inner chamber 13 of the main body 100. 21 to body
100 is pressed and fixed from the inside through a packing 27 into a fluid tight seal. The pressing and fixing means is a support column 26 having a pivot 261 at one end, and the other end surface of the support column 26 is welded to the center of the pressing plate 25.The outer periphery of the pressing plate 25 is provided on the inner periphery of the flow pipe 20 on the outlet 24 side. The bottom surface of the main body 100 is pressed by the pivot 261 by screwing the stepped portion 23 with a screw or the like, and the packing 27 is evenly pressed. An outflow window 251 is opened in the pressing plate 25 as shown in FIG. 3C, and the fluid to be measured flows in through the inflow port 21 and the main body 100.
Flows out of the empty chamber 13 through the outside of the base member 12 through the outflow port 24. The flow rate is detected by detecting the fluid vibration. The fluid vibration is detected at the vent or the output port where the fluid vibration is generated. However, when it is performed at the output port, the S / N is also excellent. Since the phases at the output port of one LPA differ from each other by π, twice the fluid vibration can be detected. Furthermore, since a phase delay occurs in each stage among LPA-A, B, and C, by adding detection signals of all output ports, vibration detection with higher resolution becomes possible. The detection means is preferably pressure detection or temperature detection means, and a specific pressure detection method is that the plate pressure on the output port side of the cover plate is formed into a thin film (not shown) and changes according to the pressure fluctuation in the thin film part In order to detect the change in strain amount, a strain gauge is attached to the thin film portion or a pressure detector is attached to the output port of the cover plate to directly detect pressure. As a temperature detection method, a heat-sensitive resistance wire such as a platinum wire or a thermistor is attached to the output port, and it is detected as a resistance change from heat dissipation due to flow.

FIG. 4 relates to another mounting method of the main body 100,
Reference numerals 01 and 202 denote pipes joined by the respective flanges 203 and 204, and a through hole through which a fluid flows is provided in a central portion of a mounting plate 30 sandwiched between the pipes 201 and 202 and into a portion corresponding to the vacant chamber 13 of the main body 100. The holes are welded and integrated so that the openings of the vacant chamber 13 are aligned with each other, and the flanges 203 and 204 are inserted into the through holes 31 penetrating the bolts and are bolted to the pipes 201 and 202. The fluid to be measured flows like the arrow Q.

FIG. 5 shows another embodiment of the present invention, in which the flow of the fluid to be measured in FIGS. 1 and 2 flows in through the inflow port 21, passes through the outer peripheral portion of the base member 12, and the outflow port. On the other hand, in the present embodiment, the fluid flowing from the base member 121 into the LPA penetrates the base member 121 again through the vent of the LPA and flows through the outflow hole to flow in the base member 121 in the Q direction. It flows out through the outflow hole 122. The constituent elements are the same as those in FIGS. 1 and 2, but the functional contents are different. That is, as shown in the figure, the base member 121 has a partition wall 120 for blocking the inflow and outflow portions, and the partition wall 120 blocks the inflowing fluid so as to flow only to the respective main flow paths 14A, 14B, 14C, The outflow fluid from the vent of each LPA is discharged from the outflow port 122 through a through hole passing through the base member 121 toward the outflow port 122 at the vent portion. The through hole is L
In the PA-A section, AC 81,91 and AC 61,71 respectively open at the positions of the upstream vents 8,9 and the downstream vents 6,7. As well
In LPA-B and LPA-C, BC81,91 and BC61,71 are shown, and in LPA-C, CC81,91 and CC61,71 are shown. In this embodiment, the same operation as that of the LPA flowmeter shown in FIGS. 1 and 2 is performed except that the fluid flows in and out of the base member 121.

Effect As described above, according to the LPA flowmeter of the present invention, the impedance of each return flow path is completely equal in the fluid oscillator having the circulating feedback function of the LPA that is multistage fluid amplified, and the apex angle of the base member is Since it is a return flow path that is perforated by sandwiching it, it has the shortest path, and since the impedance is low, the delay is small and a stable oscillation circuit can be formed. In addition, because the main flow path communicating with the fluid supply port and the outflow path have the same impedance, more stable fluid oscillation can be obtained. Therefore, it is possible to measure the flow rate in a wide range, and to connect to the pipe like a normal flow meter. Can be installed.

[Brief description of drawings]

FIG. 1 is a developed configuration diagram of a flow meter according to the present invention, FIG. 2 is a view showing a main body 100 of an LPA flow meter according to the present invention, and FIG. 3 is a view showing a flow meter in which the main body 100 is mounted. , Fig. 4 shows
FIG. 5 is a diagram showing another mounting method, FIG. 5 is a diagram showing another embodiment of the present invention, FIG. 6 is a diagram showing a basic form of LPA, FIG.
FIG. 8 is a diagram showing components of an oscillation circuit and a conventional LPA flow meter, respectively. A, B, C …… LPA, 12 …… Base member, 20 …… Flow tube, 25 …… Pressing plate, 26 …… Supporting pillar, 100 …… Main body.

Claims (10)

[Scope of utility model registration request] 1. A base member, which is an odd-numbered n-sided cylinder, having a main flow passage penetrating from each inner wall surface to the outer wall surface, and a return flow passage penetrating the outer wall surface with each apex angle sandwiched therebetween. , A plate-shaped first, second, ..., Nth laminar flow proportional amplification element and a cover plate welded and laminated on one surface of the laminar flow proportional amplification element, and the other surface of each laminar flow proportional amplification element Are fixed to the outer wall surface of the base member, the fluid supply ports of the respective laminar flow proportional amplification elements are connected to the main flow path, and the first, second, ..., Nth control ports are sequentially connected through the return flow path to the n-th flow path. The first, ..., Nth output ports are connected to each other to form a circulation path, and the main body section generates fluid vibration proportional to the flow rate of the fluid flowing in from the main flow path and flowing out from the vent, and the fluid vibration. A laminar flow proportional amplification element flowmeter characterized by comprising a detection section for detecting. 2. A partition wall is provided in a section between a main flow path and a return flow path in a square tube of a base member, and a fluid flowing into a laminar flow proportional amplification element from a front portion of the partition wall is a wall surface of the base member at a vent portion. The laminar flow proportional amplification element flowmeter according to claim 1, wherein the flowmeter flows out from the rear portion of the partition wall through an outflow passage that penetrates through the flowmeter. 3. A through hole is provided in the cover plate at the vent portion of the laminar flow proportional amplification element, the base member discharge port is closed, and the fluid flowing into the laminar flow proportional amplification element flows out of the base member through the cover plate through hole. The laminar flow proportional amplification element flowmeter according to claim 1. 4. A base member is coaxially housed in a cylindrical outer casing,
The laminar flow proportional amplification element flowmeter according to claim 1 or 2, wherein an end face between the cylinder and the base member in the cylinder is sealed. 5. The method according to claim 1 or 3, wherein the base member square tubular portion is fixed to a disc pierced at the position of the opening of the base member square tubular portion, and the disc is clamped by a pipe flange. Laminar proportional amplification element flowmeter. 6. The detection part is formed as a thin plate at the output port of the cover plate, and is detected as a strain change caused by fluid vibration of the thin plate strain. A laminar flow proportional amplification element flowmeter according to. 7. The laminar flow proportional amplification according to any one of claims 1 to 5, wherein the detection section is detected as a resistance detection value of a temperature sensitive resistor arranged at an output port portion of the cover plate. Element flow meter. 8. The method according to claim 1, wherein the fluid vibration is output by adding detection signals of the first, second, ..., Nth laminar flow proportional amplification elements. Laminar proportional amplification element flowmeter. 9. An odd-numbered n-sided cylinder is an equilateral triangle.
Item 7. A laminar flow proportional amplification element flowmeter according to any one of items 8 to 8. 10. The laminar flow proportional amplification element flowmeter according to any one of claims 1 to 8, wherein the inner wall surface of the base member is a cylindrical surface.