JPH0732523U - Measuring instrument for fluid flow meter - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a measuring instrument that can be easily manufactured by being used in a fluidic flow meter without being affected by external vibration. [Structure] A rubber-molded inner case 14 is airtightly surrounded by an outer case 18. The pressure gradient type sensors 10a and 10b having the same performance are placed in the cylindrical hole of the inner case so that the surfaces of the same poles face each other, and the space 1
7 are fixed airtightly. Spaces 19 and 20 are formed between the back surfaces of both sensors and the outer case 18, and through holes 26 and 27 that communicate with pressure extracting through holes of the fluidic element are formed in the outer case 18, and two guiding grooves 28, Through holes 23, 24, 25 for communicating the through holes 26, 27 with the spaces 17, 19, 20 via 29 are formed in the inner case 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a measuring instrument for detecting a frequency of vibration generated by a fluidic flowmeter, which is used in combination with a fluidic device which generates a vibration having a frequency proportional to a flow rate when a fluid is passed through.

[0002]

[Prior art]

 The fluidic element is a kind of oscillator that generates a vibration having a frequency proportional to the flow rate by the fluid flowing in the casing. A fluidic flow meter is a flow meter that uses this element to know the flow rate of a fluid, and an electrical sensor is used to measure the frequency of generated vibration.

The fluidic element is constructed as shown in the sectional view of FIG. That is, the target 2, the flow guide projections 3 and 3, and the flow guide wall 4 are formed in the casing 1. When the fluid is ejected from the nozzle 5 toward the target 2, the fluid is the target 2, the projection 3 Because of the flow guiding wall 4, the two flows of the white arrow a and the hatching arrow b are alternately taken and flow out from the outlet 6.

As described above, the fluid flowing out while alternately changing the flow path generates vibration due to a change in pressure when the streamline is changed. The frequency of this vibration is such that a part c or d of the flow going to the lateral part of the nozzle 5 which has become dead creates pressure at the dead part, and at this time, negative pressure is applied at the part opposite to the nozzle. Is generated, this pressure change can be measured by introducing it to the measuring instrument through the holes 7 and 8.

That is, as shown in FIG. 6, one pressure gradient type sensor 10 capable of obtaining an output proportional to the pressure gradient between two points is provided in a U-shaped tube 9 communicating with the through holes 7 and 8 at both ends. (For example, a microphone or a piezoelectric film sensor) is attached with the tube 9 blocked. When the positive pressure is applied to the through hole 7 side and the negative pressure is applied to the through hole 8 side, the diaphragm 11 of the sensor 10 is curved so as to be convex toward the through hole 8 side as shown in FIG. When the positive pressure is applied to the side, the diaphragm 11 bends convexly toward the through hole 7 as shown in FIG. Therefore, if the electrical output of the sensor 10 is measured and the frequency of the fluctuation is known, the flow rate of the fluid passing through the fluidic element can be known.

When the vibration pressure generated by the fluidic element is measured by the sensor 10 as described above, if noise or mechanical vibration is applied to the casing 1 from the outside, the operation of the sensor 10 is affected by noise or mechanical vibration. Uncertainty and inaccurate flow measurement of fluidic flow meters.

In order to eliminate the influence of such external vibration, it has been considered that the influence of external vibration is offset and removed by a measuring instrument using two sensors as shown in FIG. The measuring instrument shown in FIG. 9 is configured by providing two sensors 10a and 10b having the same performance with opposite polarities to each other and in tubes 12 and 13 whose both ends communicate with the through holes 7 and 8 of the fluidic element. It In order to reverse the polarities of both sensors, one tube 12 is bent linearly and the other tube 13 is bent S-shaped.

According to this structure, when positive pressure is applied to the through hole 7, this positive pressure is applied to the left side of the sensor 10a and the right side of the sensor 10b in FIG. 9, and the negative pressure of the through hole 8 is applied to both sensors. Join the other side of the above. As a result, output with the same polarity is generated from both sensors 10a and 10b, and both outputs can be added to be the output of the measuring instrument. Even if external vibration F is applied to the flow meter, both sensors 10a and 10b will output. Output due to external vibration is canceled out and does not interfere with flow rate measurement.

[0009]

[Problems to be solved by the device]

 In order to construct a measuring device for a fluidic flow meter as shown in FIG. 9, a straight pipe 12 and a pipe 13 bent in an S shape must be formed, and the sensors 10a and 10b must be inserted therein, so that the fabrication is difficult. It is extremely troublesome.

[0010]

[Means for Solving the Problems]

 Two pressure gradient type sensors with the same performance are placed in an elastic inner case with both ends blocked and are airtightly fixed with the same poles facing each other, and the pressure gradient type sensors are connected to a through hole that takes out the pressure of the fluidic element. The inner case is hermetically enclosed by the outer case having the through holes, and the space between the two sensors facing each other and the space on the opposite side of both the sensors are individually communicated with the through holes for taking out the pressure of the fluidic element. A hole and guide groove are formed on the outer surface of the inner case to construct a measuring instrument for fluidic flow meters.

[0011]

[Action]

 The positive and negative pressures of the fluidic element that entered the two guide grooves on the outer surface of the inner cylinder from the two through holes of the outer case are the space between the two pressure gradient type sensors facing the same pole and the respective pressures. Since it is guided to the space on the opposite side of the sensor, pressure fluctuations occurring in the fluidic element are measured by two sensors, and the outputs of these are summed and output as the output of the measuring instrument of the fluidic flow meter.

Since this measurement is performed with two sensors, the magnitude of the output is doubled.

Since the through hole and the guide groove are formed in the inner case and the outer case surrounding the two sensors to guide the pressure fluctuation to the sensor, the manufacturing is easier than the conventional structure in which the pressure fluctuation is guided by the pipe.

[0014]

【Example】

 1 to 4 show an embodiment of a measuring instrument of the present invention, FIG. 1 is a side view in which an outer case is cut, FIG. 2 is a schematic sectional view of the measuring instrument taken along the line AA of FIG. 1, and FIG. FIG. 4 is a schematic sectional view of the measuring instrument along the line BB, and FIG. 4 is a schematic diagram showing the concept of the passage of pressure applied to both sensors.

A cylindrical hole 15 is formed in the center of an inner case 14 made by molding rubber, and two pressure gradient type sensors (a microphone is used in this embodiment) 10a and 10b having the same performance are provided. The poles are faced to each other and abutted against the inner flange 16 formed in the intermediate portion of the cylindrical hole 15 to fix the inside of the cylindrical hole in an airtight manner. A space 17 is formed between both sensors. The inner case 14 is airtightly wrapped by the outer case 18. Spaces 19 and 20 are formed on the opposite side of the space 17 between the two sensors 10a and 10b. 22 is led to the outside. On the side surface of the inner case 14, a through hole 23 communicating with the space 17 and through holes 24, 25 communicating with the spaces 19, 20 are formed. The outer case 18 is formed with through holes 26 and 27 which communicate with the through holes 7 and 8 of the fluidic element, respectively. A guide groove 29 is formed to connect the No. 28 and the through holes 23, 27.

In the measuring instrument configured as described above, the through hole 26 of the outer case and the through hole 7 of the fluidic element are communicated with each other, and the through hole 27 and the through hole 8 of the same element are communicated with each other, so that the fluidic flow rate is increased. Used as a measuring instrument.

When positive pressure is applied to the through hole 7 of the fluidic element and negative pressure is applied to the through hole 8, a positive pressure is applied to the spaces 19 and 20 through the through hole 26, the guide groove 28, and the through holes 24 and 25 of the measuring instrument. Then, a positive pressure is applied to the back surfaces of the sensors 10a and 10b, and a negative pressure is applied to the surfaces of the sensors 10a and 10b through the guide groove 29, the through hole 23, and the space 17. As a result, the diaphragms of both sensors are curved so as to be convex toward the space 17 side. When the positive and negative pressures entering the through holes 7 and 8 of the fluidic element are reversed, the spaces 19 and 20 become negative pressure and the space 17 becomes positive pressure, and the diaphragms of both sensors bend in the opposite direction. When a positive or negative pressure is alternately applied to the through holes 7 and 8 due to a jet of a fluid such as a gas passing through the fluidic element, the alternating frequency is the positive or negative pressure generated by the fluidic element due to the output of the microphone which is the sensor. The alternating frequency of can be measured. In this case, even if an external vibration F is applied to the measuring instrument, the diaphragms of the two microphones having the same performance move in opposite directions with respect to positive and negative polarities, so that the outputs are canceled out, so that the fluidic element is It does not affect the measurement of positive and negative pressure changes.

[0018]

[Effect of device]

 (1) The pressure change generated by the fluidic element can be taken out and measured as the output of two sensors. Since this measurement can be performed as the sum of the outputs of the two sensors, a large output can be obtained.

(1) Even if external vibration is applied, the outputs of the two sensors are canceled by this, so that the flow rate measurement will not be inaccurate due to the influence of external vibration.

(3) It is easy to form the radial through holes 23 to 25 and the guiding grooves 28 and 29 in the inner cylinder 14 by using an elastic material such as rubber or plastic. It is easy to wrap the inner cylinder in the outer cylinder 18 in an airtight manner, and it is easy to manufacture a measuring instrument that is not affected by external vibration.

[Brief description of drawings]

FIG. 1 is a side view of a measuring instrument of the present invention with an outer case cut off.

2 is a schematic sectional view of the measuring instrument taken along the line AA in FIG.

3 is a schematic cross-sectional view of the measuring instrument taken along line BB of FIG.

FIG. 4 is a schematic diagram showing the passage of pressure applied to two sensors.

FIG. 5 is a cross-sectional view showing the structure of a conventionally known fluidic element.

FIG. 6 is a schematic diagram showing a conventional means for measuring a pressure change in a fluidic element.

FIG. 7 is a schematic diagram showing the curvature of the diaphragm of the sensor in the measuring means of FIG.

FIG. 8 is a schematic diagram showing the curvature of the diaphragm when the positive and negative pressures inside the fluidic element change.

FIG. 9 is a schematic diagram showing a conventional method for measuring a pressure change in a fluidic element using two measuring elements.

[Explanation of symbols]

 1 Casing 2 Target 3 Flow Protrusion 4 Flow Wall 5 Nozzle 6 Outlet 7, 8 Through Hole 9 Tube 10 Pressure Gradient Sensor 10a, 10b Sensor 11 Vibration Plate 12, 13 Tube 14 Inner Case 15 Cylindrical Hole 16 Inner Flange 17 Space 18 Outer case 19, 20 Space 21, 22 Conductive wire 23, 24, 25, 26, 27 Through hole 28, 29 Conductive groove

Claims (1)

[Scope of utility model registration request] 1. A pressure gradient type sensor having the same performance is fixed in an elastic inner case whose both ends are closed at intervals, and the same poles are opposed to each other in an airtight manner to fix the pressure of the fluidic element. The inner case is airtightly surrounded by an outer case having a through hole that communicates with the through hole, and the space between the two sensors facing each other and the space on the opposite side of both sensors are connected to the through holes for taking out the pressure of the fluidic element. A measuring instrument for a fluid flow meter, which has a through hole and a guide groove separately formed on the outer surface of the inner case.