JPH07174595A - Vane wheel-type flowmeter of branched structure - Google Patents

Abstract

PURPOSE:To provide a vane wheel-type flowmeter of branched structure which is turned quickly responding to a fluid at a small flow rate by reducing the weight of a vane wheel itself and which can measure a flow rate surely irrespective of whether the flow rate is large or small. CONSTITUTION:A vane wheel 3 which can be turned freely is installed inside a branching chamber 2 on the branched stream which is branched from a main stream, a magnet 3e is arranged and installed in a circumferential position which is close to the axial center of the vane wheel 3, and a magnetic field which is generated by the magnet 3e is detected by a detection means 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shunt type impeller type flow meter, and more particularly to a shunt type impeller type flow meter for measuring the flow rate of a fluid by a magnetic field fluctuation generated by a magnet attached to an impeller rotating according to the flow rate. .

[0002]

2. Description of the Related Art Conventionally, as a flow meter of this type, a magnet having a magnet embedded in the blade tip side surface of an impeller has been widely used.

[0003]

However, in order to embed the magnet in the blade tip side surface portion of the impeller, the thickness of the blade must be set so that the magnet can be embedded, and therefore the weight of the blade itself is reduced. Since it increases, there is a problem that it does not rotate promptly with a small flow rate of fluid. In order to reduce the weight of the impeller itself, if the thickness of the blade in which the magnet is not embedded is made lighter or thinner than the thickness of the blade in which the magnet is embedded, this time the dynamic balance becomes unbalanced due to the weight difference between the two blades. Invites equilibrium,
As a result, an unbalanced rotational force is added to the rotation of the impeller, and the rotation of the impeller does not necessarily respond to the flow rate of the fluid, so there is a problem that an accurate flow rate cannot be measured. .

The present invention is proposed in view of the above problems, and an object thereof is to reduce the weight of an impeller itself, and the impeller rotates promptly even for a fluid having a small flow rate so that the flow rate is large or small. It is an object of the present invention to provide a shunt type impeller type flow meter capable of reliably measuring the flow rate regardless of the above.

[0005]

In order to achieve the above object, the present invention provides a diversion chamber provided in a diversion flow path from a mainstream, an impeller rotatably supported by the diversion chamber, and the impeller. A magnet attached to the and a detection means provided outside the diversion chamber for detecting the magnetic field of the magnet, and measures the flow rate of the fluid by detecting the fluctuation of the magnetic field due to the rotation of the impeller. In the flowmeter described above, the magnet is arranged at a circumferential position close to the diametrical axis of the impeller.

[0006]

With the above structure, since the magnets are arranged at the circumferential positions close to the diametrical axis of the impeller, the thickness of all the blades can be made lighter and thinner than before. The weight of the impeller can be significantly reduced by that amount, and the impeller can be rotated promptly even for a small amount of fluid to measure the flow rate of this fluid, and the thickness of all blades can be made uniform. The dynamic balance imbalance caused by the difference in blade weight can be eliminated by changing the system, and the fluctuation of the magnetic field generated by the magnet attached to the smoothly rotating impeller can be detected according to the flow rate of the fluid. By doing so, the flow rate of the fluid can be accurately measured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow-dividing vane wheel type flow meter according to the present invention will be described based on embodiments of the drawings. FIG. 1 is a front view of the embodiment, and FIG. 2 is a side view thereof. The flow dividing type impeller type flow meter shown in the figure is roughly divided into a main pipe 1 in which a main flow flows, a flow dividing chamber 2 integrally provided on an upper surface of the main pipe 1, and a rotatably supported inside the flow dividing chamber 2. Impeller 3 and a permanent magnet 3 attached to the impeller 3
e and the detection means 4 arranged outside the flow dividing chamber 2.

The main pipe 1 has an upstream side 1a and a downstream side 1a.
A flange 1c that can be connected to another pipe is formed on both end faces with b, and is composed of a general pipe body having an inner peripheral surface 1d through which a fluid can flow, and the upstream side 1a on the inner peripheral surface 1d. At the center between the downstream side 1b and the downstream side 1b, an orifice plate 1e having a predetermined opening on the plate surface is provided. The orifice plate 1e provides flow resistance to the main flow of the fluid flowing in the main pipe 1 The pressure difference is generated between the upstream side and the downstream side in the passage.

On the upper surface of the main pipe 1, there are provided a diversion hole 1f and a return flow hole 1g communicating with the after-mentioned diversion chamber 2, and the diversion chamber 2 is provided in a part of the main flow flowing in the main pipe 1. It is configured to form a bypass flow path therethrough. In this case, the diversion hole 1f is formed to have a hole diameter smaller than the blade width of the impeller 3 described later so that the action of the fluid on the blade 3c can be effectively used.

The flow dividing chamber 2 is a block body 2 integrally provided on the upper surface of the main pipe 1 with a watertight packing 2a interposed therebetween.
The inner surface of b is opened at its lower end so as to communicate with the flow dividing hole 1f and the return flow hole 1g, and the shaft is provided in the flow dividing chamber 2 in a direction orthogonal to the flow of the fluid in the main pipe 1. Body 2c
Is fixed, and the impeller 3 described later is rotatably supported on the shaft 2c.

Further, the widthwise dimension of the flow dividing chamber 2 is formed so that the blades 3c of the impeller 3 do not interfere with the rotation. The vane wheel 3 includes a plurality of blades 3c radially planted in a boss portion 3b having an axial hole 3a at an equal angle, and a pair of permanent magnets 3e arranged in a buried shape on the outer peripheral surface of the boss portion 3b. The shaft hole 3a is loosely rotatably fitted into the shaft body 2c fixed in the flow dividing chamber 2 via the bearing 3f.
It is configured to rotate according to the flow rate of the fluid flowing from f.

The detecting means 4 is a permanent magnet 3 embedded in the impeller 3 outside the side wall 2d of the flow dividing chamber 2.
A magnetic sensor 4a provided at a portion facing a magnetic field region generated from e and a connection plug 4b connected to the magnetic sensor 4a, and fluctuations in the magnetic field generated between the permanent magnets 3e as the impeller 3 rotates. Is configured to detect. Next, the operation of the embodiment configured as described above will be described.

This embodiment is used by connecting and connecting via a flange 1c between the main fluid flow pipes (not shown) to be measured. The fluid flowing through the pipe enters from the upstream side of the main pipe 1 and comes into contact with the partition of the orifice plate 1e, and the pressure inside the pipe on the upstream side 1a of the orifice plate 1e rises, so that a part of the main flow of this fluid occurs. Flows into the flow dividing chamber 2 through the flow dividing hole 1f.

On the other hand, a part of the main flow other than the predetermined amount used for measurement flows directly from the flow hole 1h having a predetermined opening amount opened in the orifice plate 1e to the downstream side 1b. However,
The fluid that has flowed into the flow dividing chamber 2 collides with the blades 3c of the impeller 3, and the collision energy causes the impeller 3 to rotate in the fluid flow direction. Due to the rotation of the impeller 3, the directionality of the magnetic field generated by the pair of permanent magnets 3e provided on the impeller 3 changes according to the rotation cycle.

The magnetic sensor 4 of the detecting means 4 detects this fluctuation period.
The flow rate of the fluid flowing in the main pipe 1 is detected by detecting the detected value as a count value and reflecting it as a count signal in a computing device (not shown) via the plug 4b electrically connected to the magnetic sensor 4a. . In this case, in the present invention, since the permanent magnet 3e is arranged on the circumference of the boss 3b of the impeller 3, the distance between the magnetic fields can be shortened as much as possible, so that a strong magnetic field can be generated and the detection accuracy of the magnetic sensor 4a can be increased. Can be effectively improved, and the thickness of the blade 3c can be minimized and thinned as compared with the conventional one in which the permanent magnet 3e is provided at the outer peripheral end of the blade 3c, and the weight of the impeller 3 itself is significantly increased. Because it can be reduced
The impeller 3 rotates easily and promptly and smoothly even with a small amount of flow energy, so that the flow rate of the fluid can be reliably measured without being affected by the magnitude of the flow rate.

The shunt of the fluid that has rotated the impeller 3 in the shunt chamber 2 is naturally discharged from the return hole 1g to the downstream side where the internal pressure is low, and flows out from the flow hole 1h of the orifice plate 1e. It merges with a part of the main stream, and then returns to the original main stream state and flows further downstream.

[0017]

As described above, according to the present invention, in the structure of the flow-dividing vane wheel type flow meter, the magnet for generating the magnetic field that fluctuates with the rotation of the vane wheel is provided around the diametrical axis of the vane wheel. By arranging in a circular position, the thickness of the blade of the impeller can be made as thin and light as possible, so that the weight of the impeller itself can be reduced accordingly.
The impeller rotates swiftly even for a small amount of fluid, and the flow rate of this fluid can be reliably measured, and the thickness of all the blades can be made uniform, so that the thickness of the blade can be made different from the conventional one. The resulting imbalance of the dynamic balance of the impeller can be eliminated, and an impeller that can smoothly rotate according to the flow rate of the fluid can be obtained.
By detecting the magnetic field generated by the magnet attached to the impeller, it is possible to obtain a significantly improved effect as compared with the conventional case in which the flow rate of the fluid can be measured more accurately.

[Brief description of drawings]

FIG. 1 is a partially sectional front view of an embodiment showing the present invention.

FIG. 2 is a side view with a partial cross section of FIG.

[Explanation of symbols]

 (2) Flow dividing chamber (3) Impeller (3e) Magnet (4) Detection means

Claims (1)

[Claims] 1. A diversion chamber provided in a diversion channel from a main flow, an impeller rotatably supported by the diversion chamber, a magnet attached to the impeller, and an outside of the diversion chamber. A flowmeter for measuring the flow rate of a fluid by detecting a magnetic field of the magnet provided with a detection means for detecting the magnetic field of the magnet. A shunt type impeller type flow meter characterized by being arranged at a circumferential position close to the heart.