JP5624312B2 - Flow sensor - Google Patents

Description

  The present invention relates to a flow rate sensor that is installed in the middle of a fluid pipe and detects the flow rate of fluid.

  Conventionally, as this type of equipment, a fixed blade (inclined blade) that generates a swirling flow is disposed on the upstream side of the flow path, and the flow path is disposed downstream of the fixed blade so as to rotate in response to the swirling flow. There is known a flow rate sensor that arranges a rotating blade that is rotatable about the central axis of the shaft, detects the number of rotations of the rotating blade, and detects the flow rate of the fluid flowing in the flow path. This detection can be performed, for example, by magnetizing the rotary blade and providing a magnetic sensor (Hall element) outside the flow tube of the flow sensor so as to face the rotary blade.

  As such a flow rate sensor, the one disclosed in the following patent publication is known as the prior art, but each has the following problems.

Japanese Patent Publication No. 7-37906 Japanese Patent No. 3615667

  Patent Document 1 discloses a flow rate sensor in which the number of fixed blades is an adjacent natural number larger than the number of rotating blades. In this Patent Document 1, the number of fixed blades and the number of rotating blades are described for combinations of 5 and 4, or 6 and 5 respectively. In the case of detecting the rotation at, it is necessary that the number of rotating blades be an even number. Therefore, the technology using substantially even number of rotating blades and one fixed blade more than that is described. It can be said that. According to Patent Document 1, when there are five fixed blades and four rotating blades, the water flow that is swirled by the fixed blades always acts on any of the rotating blades, regardless of the state of the stationary blades. For this reason, it is described that the rotating blades are reliably rotated.

  In Patent Document 2, on the premise of the technique in which the number of fixed blades is increased by one as compared with the number of rotating blades as described above, four rotating blades and seven fixed blades are used to obtain noise reduction. A sheet flow sensor is disclosed.

  However, in order to simplify the configuration of the flow sensor, when the rotor blade bearing is molded from a synthetic resin, there is a concern that the bearing wear may be large and lack durability, and noise caused by the rotation of the rotor blade may occur. However, it was necessary to further reduce it.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to further reduce noise and improve the durability of the flow sensor.

The present invention relates to a first cylindrical inner wall portion that constitutes a fluid inlet into which a fluid flows, a second cylindrical inner wall portion that is larger in diameter than the first cylindrical inner wall portion, and an inflowing fluid. An even number of six or more fixed blades that generate a swirling flow, a peripheral annular portion that supports the fixed blade at its outer peripheral portion, and a first bearing that supports the fixed blade at its inner peripheral portion, A fixed blade portion accommodated in the second cylindrical inner wall portion, four rotary blades provided on the downstream side of the fixed blade portion in the fluid inflow direction and rotating in response to the swirling flow, and a central axis of the rotary blade A rotating blade portion having a support shaft provided in the shaft, a cylindrical portion that accommodates the rotating blade portion, and a second bearing, and a fluid inflow direction from the fixed blade portion of the second cylindrical inner wall portion A cylindrical container disposed on the downstream side; and a detecting means for detecting the rotation of the rotary blade, Both ends of the support shaft of the roller blade portion are supported by the first bearing and the second bearing, and the peripheral annular portion is set to have the same width as the step of the first cylindrical inner wall portion and the second cylindrical inner wall portion. The cylindrical portion is set to be smaller than the step of the first cylindrical inner wall portion and the second cylindrical inner wall portion, and the rotating blade is set to have the same diameter as the inner diameter of the peripheral annular portion, The angle formed between the tip of the fixed blade and the first cylindrical inner wall is set to be more than 90 °.

According to the flow rate sensor described in the first means, the fixed blade is more than the even number of six or more fixed blades, the peripheral annular portion that supports the outer periphery of the fixed blade, and the first bearing that supports the inner periphery of the fixed blade. The rotary blade portion is formed by four rotary blades and a support shaft provided at the center of the rotary blade, and the cylindrical portion that accommodates the rotary blade, and the cylindrical bearing body from the second bearing Each blade portion can be configured simply by inserting them into the body .
Moreover, the outer diameter of the fixed blade is the same as the inner diameter of the first cylindrical inner wall portion, and the angle between the tip of the fixed blade and the first cylindrical inner wall portion is more than 90 °, thereby reducing the generation of turbulent flow. In addition, the swirl flow can be efficiently made into a swirl flow with less resistance, and the swirl flow is all rotated by rotating the swirl flow with the same outer diameter as that of the fixed blade. The number of fixed blades is 6 and the number of rotating blades is 4, and even if the rotational speed of the rotating blades is reduced, the rotational speed is linearly increased or decreased according to the flow rate of the fluid. be able to. Thereby, the durability is improved without degrading the performance (resolution) of the flow sensor. The above-described effects can be achieved with a very simple configuration.

The perspective view of one Example of this invention, The figure seen from the diagonally left back direction of FIG. Front view Same as above Left side view Same as above Sectional view of FIG. 3A-A line Characteristics graph of the flow sensor when there are 6 (even) and 5 (odd) fixed blades

  The present invention is a flow rate sensor comprising a fixed blade for generating a swirling flow, a rotating blade rotated by the swirling flow, and a detecting means for detecting the rotation of the rotating blade. It has and performs each action.

  One embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 1 denotes a flow sensor device which is entirely formed of a synthetic resin material, and an inner diameter portion of the flow device has a cylindrical shape. The inner diameter portion of the container body 1 is formed with a first cylindrical inner wall portion 1a, a second cylindrical inner wall portion 1b, and a third cylindrical inner wall portion 1c from the upstream side to the downstream side of the fluid. Become.

  In this embodiment, the outer shape of the upstream end in the fluid inflow direction of the vessel body 1 is in the shape of a male joint inserted into a female joint provided in a flow pipe to which the flow sensor is connected, and The inner shape of the end portion in the opposite direction (end portion outer shape on the downstream side in the fluid inflow direction) has the shape of a female joint into which a male joint provided in a flow pipe to which the flow sensor is connected is inserted.

  Reference numeral 2 denotes a fluid inlet portion of the container 1, and the first cylindrical inner wall portion 1 a constitutes a fluid inlet portion 2. A fixed blade portion 3 is provided on the second cylindrical inner wall portion 1b formed at the back of the first cylindrical inner wall portion 1a.

  The inner diameter of the first cylindrical inner wall portion 1a and the inner diameter of the peripheral annular portion 4 of the fixed blade portion 3 (that is, the outer dimensions of the fixed blade 3 'provided inside the peripheral annular portion 4) are the same diameter. And there is no step between them. In other words, the thickness of the peripheral annular portion 4 is set to the same width as the step between the first cylindrical inner wall portion 1a and the second cylindrical inner wall portion 1b. Thereby, the fluid which flows in into the 1st cylindrical inner wall part 1a flows in into the fixed blade | wing part 3 smoothly, without being disturbed.

  The fixed blade portion 3 includes six fixed blades 3 ′ for generating a swirling flow in the fluid flowing in from the first cylindrical inner wall portion 1 a, and a peripheral annular portion 4 connecting the outer end portions of the fixed blades. The first bearing 6 connects the inner end portions of the fixed blades at the central shaft portion of the container body 1 and is integrally formed of synthetic resin. The first bearing 6 rotatably supports a fluid inflow side end portion of a support shaft 5 described later.

  The number of the fixed blades 3 'is an even number of 6 in this example.

  Each of the fixed blades 3 ′ is formed from the upstream end of the peripheral cylindrical portion 4 in the fluid inflow direction toward the center of the peripheral cylindrical portion 4, and its tip (upstream in the fluid inflow direction) The end portion 3a is formed to form an obtuse angle continuously from the first cylindrical inner wall portion 1a. That is, the tip 3a of the fixed blade 3 'is provided so as to incline in the fluid outflow direction. And in the example (refer FIG. 6) on drawing, the angle of the said front-end | tip part 3a and the said 1st cylindrical inner wall part 1a is about 140 degrees.

  As a result, the inflowing fluid can be efficiently swirled without hindering each fixed blade 3 ′ from becoming a large resistance of the fluid passing through the flow sensor and without accompanying a large turbulent flow.

  7 is a cylindrical container that is provided with a second bearing 9 that is connected to the fixed blade 3 and receives the downstream shaft end of the rotary blade 8 described later. A cylindrical portion 10 having the same outer diameter as that of the portion 4 but having a larger inner diameter, three arm plates 11 extending from the inner peripheral wall toward the central portion on the downstream side of the cylindrical portion, and supported by the arm plates The second bearing 9 is formed integrally with a synthetic resin.

  In a state where the cylindrical container 7 is mounted on the second cylindrical inner wall portion 1b, the inner wall of the cylindrical portion 10 and the inner wall of the surrounding cylindrical portion 4 have a step. In other words, the inner diameter cross-sectional area of the cylindrical portion 10 is larger than the inner diameter cross-sectional area of the surrounding cylindrical portion 7.

  Reference numeral 8 denotes a rotating blade portion composed of four rotating blades 8 'and a support shaft 5. The rotating blades are formed of a magnetic material, and the tips of the rotating blades 8' are alternately attached to the N pole and the S pole. It is magnetized.

  At the time of forming the rotary blade 8 ′, a metal (for example, stainless steel) support shaft 5 having a concave portion having a small diameter at the center is disposed at the center of rotation. The recess serves to prevent the support shaft 5 from coming off. The rotary blade portion 8 is rotatable inside the cylindrical housing 7 by inserting and supporting the front end portion and the rear end portion of the support shaft 5 in the first bearing 6 and the second bearing 9. Installed.

  As shown in the drawing, the second bearing 9 has a protrusion 5 ′ protruding in the direction of the support shaft 5 at the center thereof, which reduces the sliding resistance with the support shaft 5. ing.

  As described above, the inner diameter of the cylindrical portion 10 that accommodates the rotating blade portion 8 is formed larger than the inner diameter of the peripheral annular portion 4, and the outer diameter of the rotating blade 8 'is the fixed blade 3'. The outer peripheral diameter (in other words, the inner peripheral diameter of the peripheral annular portion 4) is the same. As a result, all of the swirling flow formed through the fixed blade portion 3 is given to the rotating region of the rotating blade 8 '.

  The fixed blade portion 3, the rotary blade portion 8 and the cylindrical container 7 are first inserted into the first bearing 6 of the fixed blade portion 3 with the tip end of the support shaft 5 of the fixed blade portion 8, and the rear end of this support shaft. Is inserted into the second bearing 9 of the cylindrical container 7, and the end portion on the upstream side in the fluid inflow direction of the cylindrical container 7 is fitted to the stepped portion formed on the outer periphery of the peripheral annular portion 4. The structure is integrated into the second cylindrical inner wall 1b from the downstream side in the fluid inflow direction of the container 1 and arranged.

  In this state, the rear end portion of the cylindrical container 7 protrudes into the third cylindrical inner wall portion 1c, so that the rear end portion is pushed around the upstream side in the fluid inflow direction. The structure is biased in the direction of the first cylindrical inner wall 1a by a metal annular elastic body (retaining ring) 15 such as stainless steel having a plurality of protrusions fitted to the inner wall of the third cylindrical inner wall 1c. Then, it is fixed inside the vessel 1.

  The fixed blade portion 3 and the rotary blade portion 8 are formed inside the vessel body 1, and the thickness of the peripheral annular portion 4 is the same as that of the first cylindrical inner wall portion 1a and the second cylindrical inner wall portion 1b. Accordingly, there is no step between the fluid inlet portion 2 and the inner wall of the peripheral annular portion 4.

  On the other hand, the outer peripheral diameter of the cylindrical portion 10 is the same as the outer peripheral diameter of the peripheral annular portion 4, and the thickness of the cylindrical portion 10 is made thinner than the thickness of the peripheral annular portion 4. As a result, the inner wall of the cylindrical portion 10 and the inner wall of the peripheral annular portion 4 have a step.

  Reference numeral 12 denotes a fluid outlet portion formed at the rear portion of the vessel body 1, and a temperature sensor installation portion 13 is provided on the outer upper portion of the fluid outlet portion. This temperature sensor installation part 13 is a part to which a temperature sensor (not shown) for detecting the temperature of the fluid passing through the flow sensor is mounted, and a probe of the temperature sensor through a through hole penetrating into the fluid outlet part. The temperature sensor is attached so that is exposed in the pipeline. On both sides of the temperature sensor installation portion 13, holes for attaching the temperature sensor or female screws are formed.

  Reference numeral 14 denotes a flange provided on the outer upper portion of the container body 1 facing the rotary blade 8, and a substrate or lead wire on which a Hall element for detecting the rotation of the rotary blade 8 ′ is installed in the flange. A sensor block (both not shown) is provided. The size and shape of the flange 14 and the thickness of the container 1 corresponding to the bottom of the flange 14 are appropriately determined in consideration of the characteristics of the Hall element to be installed, the size of the substrate, and the like. The In addition, after the sensor block substrate is disposed in the flange portion 14, the inside of the flange portion is molded with a synthetic resin material, and the sensor block substrate has a watertight structure.

  FIG. 7 is a graph showing the characteristics of the flow sensor showing the difference between the case where the number of rotating blades is four and the number of fixed blades is five and six, and the horizontal axis indicates the fluid (water). The flow rate and the vertical axis indicate the frequency of the pulse output from the Hall element (this corresponds to twice the rotational speed of the rotary blade).

  The number of output pulses (frequency) of the Hall element, that is, the number of rotations of the rotating blade part is lower than that of the six fixed blades compared to the five blades. Since the characteristics are linear, it can be seen that the flow rate detection accuracy is comparable to the five blades.

  In the case of the six fixed blades, since the number of rotations is small, the load on the bearing portions (the first bearing 6 and the second bearing 9) of the rotating blade portion is small, which is advantageous for durability and less noise.

  In the case of 6 fixed blades with respect to 4 rotating blades, the number of rotating blades that do not easily hit the swirl flow increases compared to the case of 5 fixed blades with respect to 4 rotating blades. The number of revolutions is thought to fall.

  However, as described above, the inner diameter of the fluid inlet portion 2 (first cylindrical inner wall portion 1a) and the inner diameter of the peripheral annular portion 4 that supports the fixed blade 3 ′ at its outer peripheral portion (that is, the outer shape of the fixed blade 3 ′). ) And the tip 3a of the fixed blade 3 'is inclined to the outflow direction side of the fluid so as to suppress the resistance of the fluid and the generation of turbulence as much as possible, and the rotating blade 8' Is larger than the inner diameter of the peripheral annular portion 4, and the diameter of the rotating blade 8 'is set to the diameter of the fixed blade 3' (cylindrical annular portion 7). As a result, all of the swirling flow generated by the fixed blade 3 'reaches the rotation region of the rotating blade 8', and the swirling flow efficiently hits the rotating blade 8 '. Although the number is low compared to the case of 5 rotating blades, the characteristics are obtained linearly. Considered that. As a result, a flow sensor with high accuracy and enhanced durability can be obtained.

  In the above embodiment, the number of rotating blades is four and the number of fixed blades is six. However, the decrease in the number of rotations is faster than when the swirling flow is an odd number of fixed blades. Since it is considered to be caused by the phenomenon that it is difficult to hit the blade, the fixed blade is not limited to six, and may be an even number of six or more.

  Similarly, the number of rotating blades may be an even number of 4 or more. In this case, the number of fixed blades may be different from the number of rotating blades.

  Further, the angle between the tip 3a of each fixed blade 3 'and the inner diameter surface of the first cylindrical inner wall 1c is about 140 °, but the resistance of the fluid that the fixed blade passes through the flow sensor is large. In order to make the inflowing fluid into a swirling flow without causing a large turbulent flow, the tip portion may be inclined toward the fluid outflow side at an angle of more than 90 °.

  Furthermore, in the above-described embodiment, the temperature sensor installation unit 13 is provided and the temperature sensor is disposed therein. However, it is necessary to provide the temperature sensor when the temperature of the fluid passing through the flow sensor is not required. It goes without saying that there is no.

  Furthermore, although the supporting shaft 5 that is the rotating shaft of the rotating blade is made of metal, as described above, since the rotational speed of the rotating blade is lower than that of the conventional flow sensor, the supporting shaft 5 is You may form with a synthetic resin, a ceramic, etc.

  Furthermore, in the above description, as a result of the fixed blade 3 'being formed from the end portion (fluid inflow upstream end portion) of the peripheral cylindrical portion 4, the tip portion 3a of the fixed blade 3' is the first portion. Although the obtuse angle is formed continuously from the inner surface of the cylindrical inner wall portion 1a, the fixed blade 3 'is provided slightly downstream from the fluid inflow upstream end of the peripheral cylindrical portion 4. In this case, the inner diameter portion from the end portion of the peripheral cylindrical portion 4 to the formation of the fixed blade 3 ′ may be the same inner diameter as the first cylindrical inner wall portion 1a. .

  Furthermore, in the said Example, although the both ends of the said container 1 demonstrated that the fluid inflow upstream side was a male joint, and the downstream side became the shape of a female joint, What is necessary is just to determine suitably according to the shape of the coupling provided in the flow pipe to which the flow sensor is connected. When the fluid inflow end of the vessel 1 is a female joint (that is, when a male joint provided in a flow pipe to be connected is inserted into the fluid inflow end), (1) When the male joint of the flow tube is inserted partway through the first cylindrical inner wall 1a, the first cylindrical inner wall 1a is provided with a large-diameter portion into which the male joint is inserted. The remaining part of the part 1a is made to coincide with the inner diameter of the male joint, or (2) when the male joint is inserted over the entire length of the first cylindrical inner wall part 1a, the inner diameter of the peripheral annular part 4 What is necessary is just to comprise so that (the outer diameter of fixed blade 3 ') may correspond with the internal diameter of this male joint. Thereby, the fluid that has flowed into the flow sensor hits the fixed blade without being disturbed, and can be smoothly turned.

DESCRIPTION OF SYMBOLS 1 Container 1a 1st cylindrical inner wall part 1b 2nd cylindrical inner wall part 1c 3rd cylindrical inner wall part 2 Fluid inlet part 3 Fixed blade part 3 'Fixed blade 4 Peripheral annular part 5 Support shaft 6 First bearing 7 Cylindrical shape Housing 8 Rotating blade portion 8 'Rotating blade 9 Second bearing 10 Tubular portion 11 Arm plate 12 Fluid outlet portion 13 Temperature sensor installation portion 14 Hook portion 15 Ring elastic body (retaining ring)

Claims (2)

A container body having a first cylindrical inner wall portion constituting a fluid inlet into which a fluid flows, and a second cylindrical inner wall portion having a diameter larger than that of the first cylindrical inner wall portion;
Six or more even number of fixed blades that generate a swirling flow in the inflowing fluid, a peripheral annular portion that supports the fixed blades at the outer peripheral portion thereof, and a first bearing that supports the fixed blades at the inner peripheral portion thereof. A fixed blade portion accommodated in the second cylindrical inner wall portion;
Four rotating blades that are provided on the downstream side of the fixed blade portion in the fluid inflow direction and rotate by receiving the swirling flow, and a rotating blade portion that has a support shaft provided on a central axis of the rotating blade,
A cylindrical container that has a cylindrical part that accommodates the rotating blade part, and a second bearing, and is disposed on the downstream side of the fixed blade part in the fluid inflow direction of the second cylindrical inner wall part;
Detecting means for detecting rotation of the rotary blade,
Both ends of the support shaft of the rotary blade portion are supported by the first bearing and the second bearing,
The peripheral annular portion is set to have the same width as the step of the first cylindrical inner wall portion and the second cylindrical inner wall portion,
The cylindrical part is set to be smaller than the step of the first cylindrical inner wall part and the second cylindrical inner wall part,
The rotary blade is set to the same diameter as the inner diameter of the surrounding annular portion,
The flow rate sensor characterized in that an angle between a tip of the fixed blade and the first cylindrical inner wall is set to be more than 90 °. The outer diameter of the fixed blade is the same as the inner diameter of the first cylindrical inner wall,
The outer diameter of the rotating blade is the same as the outer diameter of the fixed blade,
The flow sensor according to claim 1, wherein the number of the fixed blades is six .

Images