JPH07286872A - Flowmeter - Google Patents

Abstract

PURPOSE:To provide a flowmeter which can accurately measure the full flow rate of a fluid flowing through a flow passage even when the fluid unevenly flows and which is less in pressure loss. CONSTITUTION:A plurality of straightening vanes 2 which generate lifts by the flow of a fluid are arranged in the vertical direction in a flow passage 1 through which a fluid flows and a linear support 3 which is coupled with the vanes 2 is led out from the flow passage 1 and connected to a lift detector 5 so that the lift generated by the vanes 2 can be transmitted to the support 3, detected by means of the detector 5, and converted into the flow rate of the fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for measuring the flow rate of fluid such as gas or liquid flowing in a flow path.

[0002]

2. Description of the Related Art A flow meter conventionally used for measuring the flow rate of a gaseous fluid flowing in a flow path will be described with reference to vertical side views of FIGS. 4 to 6. FIG. The pitot tube b is projected into the inside of the flow path a, and the flow rate of the fluid is measured from the dynamic pressure and the static pressure acting on the pitot tube b. The orifice c is provided, and the flow rate of the fluid is measured by the pressure difference between the pressure in the flow channel a and the pressure at the portion where the orifice c is present. In FIG. It measures the flow rate.

[0003]

However, the flow rate of the fluid flowing in the channel a is not always uniform in the flow rate in the entire cross section of the channel a. As shown in the velocity distribution e shown in FIG. The flow velocity tends to be high in the central portion of the flow channel a and slow in the peripheral wall portion of the flow channel a.

Therefore, in the projecting pitot tube b of FIG. 4, since the pitot tube b is located at a local portion of the flow path a, a measurement error may occur due to uneven flow velocity in the cross section of the flow path a. Further, there is a drawback that measurement cannot be performed due to clogging of a measurement hole formed in the pitot tube b due to dust or the like.

Further, in the case where the orifice c of FIG. 5 is provided and the case where the venturi meter d of FIG. 6 is attached, the flow path a is locally narrowed, so that there is a drawback that the pressure loss becomes large.

The present invention eliminates such conventional drawbacks,
It is an object of the present invention to provide a flowmeter which can accurately measure the total flow rate even if there is nonuniformity of the flow and has a small pressure loss.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a plurality of airfoil straightening vanes, which generate lift due to the flow of a fluid, are arranged in a vertical direction in a fluid flow passage, and the plurality of airfoil straightening vanes are connected to each other. A linear support, which is drawn out of the flow path, and the linear support is connected to a lift detector, and
The present invention relates to a flowmeter, wherein the lift detector is a strain gauge.

[0008]

According to the first aspect of the present invention, a lift force is generated in each of the plurality of airfoil straightening vanes due to the flow of the fluid in the flow path, and the lift force is generated via the linear support connecting the plurality of airfoil straightening vanes. The total acts on the lift detector, and the lift detects the flow rate of the fluid in the entire flow path.

According to the second aspect of the present invention, since the strain gauge is used as the lift detector, the lift acting on the airfoil straightening plate can be accurately detected with a small amount of movement.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a vertical sectional side view of an embodiment of the present invention, and FIG. 2 is a vertical sectional front view of FIG. 1. Inside the flow passage 1 provided in the horizontal direction, from the left side of FIG. The fluid flows to the right, and the flow velocity of the fluid flowing inside the flow channel 1 is high in the central portion of the flow channel 1 as shown in the velocity distribution e written in FIG. At the peripheral wall of the passage 1, the flow velocity tends to be slow.

As shown in FIGS. 1 and 2, a plurality of airfoil straightening vanes 2 are arranged in a substantially horizontal posture inside the flow path 1 in a vertical direction in a state orthogonal to the fluid flow. All the airfoil straightening vanes 2 are connected by a linear support 3 such as a thin rod. Each of the airfoil straightening plates 2 is one in which a lift force is applied by the fluid flowing inside the flow path 1 like an airplane wing.

The lower part of the linear support 3 is slidably exposed to the outside of the flow path 1 and has a weight 4 attached thereto. Also, the upper part of the linear support 3 is slidably protruded to the outside of the flow path 1,
It is connected to a lift detector 5 using a strain gauge 5a. The strain detector 5a is suitable for the lift force detector 5 because the linear support 3 has a small movement amount and can directly measure the lift force accurately. However, when the detection accuracy is not so required, the linear supporter 5a is suitable. Three
It is also possible to use a position sensor or the like for detecting the movement amount of the.

In order to prevent the fluid leaking from the portion where the linear support 3 slidably extends outside the flow path 1 from being lost to the atmosphere, the linear support 3 is placed outside the flow path 1. The protruding portion is covered with the sealing cover 6.

The lift detector 5 described above is electrically connected to a flow meter 7 for converting the lift into a fluid flow rate as shown in FIG.

Next, the operation of the apparatus shown in FIGS. 1 and 2 will be described.

When the fluid flows from the left side to the right side in FIG. 1 in the flow path 1, a lift force corresponding to the flow velocity is generated by the flow of the fluid in contact with each airfoil straightening plate 2. It will occur in 2. In this case, the airfoil straightening plate 2 arranged near the center of the flow path 1 and in contact with a fluid having a high flow velocity
A large lift is generated, and a small lift is generated in the airfoil straightening plate 2 arranged near the peripheral wall portion of the flow path 1 and in contact with the fluid having a slightly low flow velocity.

The fluid in contact with the airfoil straightening plate 2 flows away to the downstream side of the flow path 1 without being greatly disturbed.

The lift generated in each airfoil straightening plate 2 according to the flow velocity of the fluid is transmitted to the linear support 3. For this reason,
The airfoil rectifying plate 2, the linear support 3, and the weight 4 which were in the lowered position by the weight 4 are integrally lifted by a force corresponding to the total lift.

This rising force, that is, the lift force is detected by the strain gauge 5a of the lift force detector 5 connected to the upper part of the linear support 3, and the detection signal of the lift force detector 5 is input to the flow meter 7. Then, the numerical value converted into the flow rate is output. As a result, the cross-sectional flow rate of the flow path 1 is determined.

FIG. 3 is a vertical cross-sectional side view of another embodiment of the present invention, in which a plurality of airfoil straightening vanes 2 which are vertically arranged in a substantially horizontal posture and orthogonal to a fluid flow, It is connected by the linear supports 3.

The lower part of the linear support 3 slidably extends outside the flow path 1 and is connected to the strain gauge 5a of the lift detector 5. The upper part of the linear support 3 is also slidably protruded to the outside of the flow path 1, and a retaining metal fitting 8 is attached to the upper end of the linear support 3 so that the upper end of the linear support 3 is connected to the flow path 1. It is designed not to fall inside the. In order to prevent the fluid leaking from the position where the linear support 3 slidably protrudes outside the flow path 1 from being lost to the atmosphere, the linear support 3 is used.
The part that is exposed to the outside is covered with a sealing cover 6.
The lift detector 5 is electrically connected to a flow meter (not shown) as in FIG.

Also in the apparatus of FIG. 3, the lift force generated in each airfoil straightening plate 2 according to the flow velocity of the fluid in the flow path 1 is entirely transmitted to the linear support 3. Therefore, the airfoil straightening plate 2, the linear support 3, and the retaining metal 8 that were in the lowered position due to their own weight ascend in an integrated state with a force corresponding to the total lift.

This ascending force, that is, the lift force is detected by the strain gauge 5a of the lift force detector 5 connected to the lower portion of the linear support 3, and the detection signal of the lift force detector 5 is input to a flow meter (not shown). Then, the numerical value converted into the flow rate is output, and the cross-sectional flow rate of the flow path 1 is determined.

The sealing cover 6 can be omitted if the penetrating portion of the linear support 3 with respect to the flow path 1 in each of the above-described embodiments is configured to be vertically slidable and sealable.

[0026]

According to the first aspect of the invention, even if the flow velocity of the fluid flowing inside the flow passage is uneven depending on the cross-section position, the flow rate of the fluid over the entire cross-section can be accurately measured, and there is no problem due to dust or the like. Effective in reducing pressure loss.

According to the second aspect of the invention, since the strain gauge is used as the lift detector, there is an effect that the lift acting on the airfoil straightening plate can be accurately detected with a small amount of movement.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an embodiment of the present invention.

2 is a vertical front view of FIG. 1. FIG.

FIG. 3 is a vertical sectional side view of another embodiment of the present invention.

FIG. 4 is a vertical sectional side view of an example of a conventional device.

FIG. 5 is a vertical sectional side view of another example of the conventional device.

FIG. 6 is a vertical sectional side view of still another example of the conventional device.

[Explanation of symbols]

 1 flow path 2 airfoil straightening plate 3 linear support 5 lift detector 5a strain gauge

Claims (2)

[Claims] 1. A plurality of airfoil straightening vanes that generate lift due to the flow of fluid are arranged vertically in a flow passage for flowing a fluid, and a linear support in which the plurality of airfoil straightening vanes are connected is used as a flow passage. A flowmeter, characterized in that it is led out to the outside and the linear support is connected to a lift detector. 2. The flowmeter according to claim 1, wherein the lift detector comprises a strain gauge.