JP3310652B2 - Flow sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow sensor for measuring the flow rates of various fluids.

[0002]

2. Description of the Related Art Conventionally, a venturi type flow meter has been widely used. As shown in FIG. 4, the venturi flow meter has a throttle 2 (throat portion) provided in the middle of the pipe 1, and the pressure of the fluid flowing through the throttle 2 and the pressure of the fluid flowing upstream of the throttle 2 are determined. Is measured, and the flow rate is determined by measuring, for example, the water head difference H during that time. This type of venturi type flow meter has an advantage that the pressure loss can be reduced because there is no protrusion in the hollow portion of the pipe 1 and the flow path is simple. That is, the pressure difference between the upstream side and the downstream side of the throttle 2 is small, and there is a characteristic that the fluid can flow with almost no resistance.

[0003] Therefore, it has characteristics that are convenient for measuring the flow rate of a fluid for which the pressure cannot be increased.

[0004]

As described above, the venturi type flow sensor has various features, but since the shape of the taper, such as the spread angle, is strictly defined, the production is troublesome and expensive. There are drawbacks that can be significant. Also, there is a disadvantage that a flow sensor having a relatively small flow rate (a small diameter of a pipeline) is difficult to manufacture and is expensive.

An object of the present invention is to provide a flow sensor which has a simple structure and can be manufactured at low cost.

[0006]

According to a first aspect of the present invention, a throttle is provided in a part of the pipeline, and a difference between the pressure of the fluid at the throttle and the pressure of the fluid upstream of the throttle is provided. In the venturi type flow sensor that measures the flow rate of the fluid flowing through the pipe by measuring the pipe, the pipe is formed by a pipe formed of a plastically deformable material, and the throttle of the pipe forming the pipe is restricted. A pressure extraction hole is formed at a position to be formed, and at the position of the pressure extraction hole, a screw shaft which is fed and moved in a direction orthogonal to the axis of the tube is provided. A flow sensor having a structure in which a portion is crushed to form a throttle is proposed.

According to a second aspect of the present invention, in the flow rate sensor according to the first aspect, the tube is disposed so as to penetrate a hole formed in the metal block, and a seal is provided between the hole and the peripheral surface of the tube. We propose a flow sensor with a structure in which only the hollow hole of the tube acts as a flow path by sealing with a material. According to a third aspect of the present invention, in the flow sensor according to any one of the first and second aspects, a screw hole is provided on a side substantially 180 ° opposite to a pressure outlet formed in the tubular body in a direction orthogonal to the axis of the tubular body. A flow sensor is proposed in which a screw shaft is mounted in the screw hole and the pipe is crushed by screwing the screw shaft.

[0008]

According to the flow rate sensor of the present invention, since the throttle is formed by crushing a part of the tube with the screw shaft, it is easier to manufacture than the structure in which the throttle is formed in advance. In particular, it is connected in series with the reference flow meter, and the throttle can be formed while comparing it with the measurement value of the reference flow meter, and the advantage that the throttle can be set while calibrating the flow value is obtained. Can be

[0009]

FIG. 1 shows an embodiment of a flow sensor according to the present invention. In the figure, reference numeral 11 denotes a metal block. As shown in FIG. 2, the metal block 11 has a prismatic shape in this example. A hole is formed at the axial center position of the prism-shaped metal block 11, and the tube 12 is penetrated and supported by the hole. For example, a pipe formed of a plastically deformable material such as stainless steel can be used as the pipe 12.

The space between the through hole formed in the metal block 11 and the tube 12 is sealed with a sealing material 13 such as an O-ring, and only the hollow hole of the tube 12 is used as a flow path. Numeral 14 denotes a seal suppressing member for suppressing the sealing material 13. Both ends of the tubular body 12 are disposed inside a cavity formed by connection ports 15A and 15B formed at both ends of the metal block 11, and a pipe (not shown in particular) is connected to the connection ports 15A and 15B. The flow path of the fluid to be measured is communicated.

Holes 16A and 16B are formed at substantially the center of the metal block 11 in the axial direction so as to face each other by 180 ° and to be perpendicular to the axial direction of the tube 12. One hole 16A
Is equipped with a measuring pressure extracting tool 17. Measuring pressure extractor 1
Reference numeral 7 is provided with a pressure outlet 17A communicating with a pressure outlet 12A formed in the tube 12, and a screw hole 17B connecting the pressure outlet 17A to pressure measuring means. The periphery of the measurement pressure extracting device 17 is sealed with a sealing material 18 to prevent the fluid flowing through the tube 12 from leaking. An escape hole 17C is communicated with the pressure extraction hole 17A, a fluid flowing through the tube body 12 is caused to flow out into the cavity formed by the holes 16A and 16B, and the inside of the cavity formed by the holes 16A and 16B is piped. The pressure is made equal to the pressure inside the body 12.

On the other hand, a female screw is formed on the circumference of the hole 16B, and a screw shaft 19 is screwed into the female screw. A seal member 21 is also attached around the screw shaft 19 to prevent the fluid to be measured from leaking outside through the hole 16B. Furthermore, the screw shaft 19
The compressor 19A is rotatably mounted on the tip of the
Attach. The tip of the compressor 19A and the measuring pressure extracting device 17
Has a spherical shape, and has a structure in which the tube 12 is crushed by the spherical surface. That is, by screwing the screw shaft 19, the compressor 19 </ b> A is pressed against the tube 12. By further screwing the screw shaft 19, the tube 12 is crushed by the pressure from the screw shaft 19. At this time, the compressor 19A
, The rotation of the screw shaft 19 can be prevented from being transmitted to the tube 12, thereby preventing the tube 12 from being threaded.

FIG. 2 shows a completed flow sensor according to the present invention. That is, the present invention proposes a flow sensor having a structure in which the position of the pressure outlet 12A of the tube 12 is crushed by screwing the screw shaft 19 to form a throttle. A pressure outlet 12B is formed in the pipe 12 also on the upstream side (on the connection port 15A side) from the position where the throttle is formed. The pressure outlet 12 </ b> B communicates with the cavity 22, and the fluid pressure led out to the cavity 22 is applied to the pressure outlet 1 formed in the metal block 11.
It is led out of the metal block 11 through 1A and the screw hole 11B.

According to the structure of the flow rate sensor according to the present invention, by screwing the screw shaft 19 toward the tube 12, the screw shaft 19 crushes the tube 12 and deforms it into the state shown in FIG. Form. Since the pressure outlet 12A is provided at the position where the throttle is formed, the pressure of the fluid at the throttle can be measured. Further, since the pressure outlet 12B is provided on the upstream side of the position where the throttle is formed, the pressure of the fluid on the upstream side of the throttle can also be measured.

As a result, according to the structure of the present invention, by measuring the difference between the fluid pressure obtained in the screw hole 17B and the fluid pressure obtained in the screw hole 11B, the pipe 12 is measured similarly to the venturi type flow sensor. The flow velocity and the flow rate of the fluid flowing through can be obtained. In particular, according to the present invention, the throttle amount of the throttle can be adjusted by adjusting the screw shaft 19 while the fluid is flowing, so that the flow sensor according to the present invention and the already-calibrated reference flow sensor are flowed. It is connected in series to the path, the measured value of the reference flow sensor and the measured value of the flow sensor according to the present invention are compared, and the state of forming the restrictor is set to a state that matches the measured value of the reference flow sensor. Calibration can be completed by setting.

[0016]

As described above, according to the present invention, a venturi-type flow sensor can be constructed with a relatively simple structure, and can be manufactured at low cost. In particular, since the step of forming the aperture can be performed simultaneously with the calibration work, the manufacturing cost can be greatly reduced. In addition, since the tube 12 is used, even if the formation of the aperture fails, only the tube 12 needs to be replaced, and in this respect, cost reduction can be expected. Further, the range of the flow rate to be measured can be changed by variously changing the diameter of the tube 12. Therefore, an advantage that a variety of flow sensors can be manufactured relatively easily is obtained, and the effect is very large for practical use.

[Brief description of the drawings]

FIG. 1 is a sectional view for explaining an embodiment of a flow sensor according to the present invention.

FIG. 2 is a cross-sectional view for explaining the operation of the main part of the flow sensor according to the present invention.

FIG. 3 is a side view of FIGS. 1 and 2 as viewed from the side.

FIG. 4 is a cross-sectional view for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Metal block 11A Pressure extraction hole 11B Screw hole 12 Tube 12A, 12B Pressure extraction port 13 Sealing material 14 Seal suppression 15A, 15B Connection port 16A, 16B hole 17 Measurement pressure extraction tool 17A Pressure extraction hole 17B Screw hole 17C Release hole 18 , 21 Sealing material 19 Screw shaft 19A Compressor 22 Cavity

Claims (3)

(57) [Claims] 1. A pipe having a throttle portion in a part thereof, and measuring a difference between a pressure of a fluid in the throttle portion and a pressure of a fluid upstream of the throttle portion to measure a difference between a pressure of a fluid flowing in the pipe and a flow rate of the fluid. In a venturi-type flow sensor for measuring a flow rate, a pipe is formed by a pipe formed of a plastically deformable material, and a pressure extraction hole is formed at a position of the pipe forming the pipe where the throttle is to be formed. At the same time, at the position of the pressure outlet, a screw shaft which is fed and moved in a direction orthogonal to the axis of the tube is provided, and a part of the tube is crushed by the screw shaft to form a throttle. A flow sensor characterized in that the flow rate sensor is structured. 2. The flow sensor according to claim 1, wherein the tube is disposed so as to penetrate a hole formed in the metal block, and a gap between the hole and a peripheral surface of the tube is sealed with a sealing material. A flow sensor having a structure in which only a hollow hole of a tubular body acts as a flow path. 3. The flow sensor according to claim 1, wherein the pressure outlet formed in the pipe body is substantially equal to the pressure outlet.
On the opposite side, a screw hole is formed in a direction orthogonal to the axis of the tube, a screw shaft is mounted in the screw hole, and the tube is crushed by screwing the screw shaft. Characteristic flow sensor.