JPH055634A - Rotary flowmeter - Google Patents

Abstract

PURPOSE:To obtain a rotary flowmeter which can be extremely easily set in a newly or already installed pipeline and has a simple structure. CONSTITUTION:This rotary flowmeter is provided with a main body 3 which is set in a pipeline 1, impeller housing section 15 which is formed in the main body and opened toward the downstream side, and impeller 17 which is housed in the section 15 and supported by the wall section 20 of the main body 3. In addition, communicating holes 27 are also formed through the surrounding wall of the main body 3 so as to rotate the impeller 17 by causing a fluid to collide with the impeller 17 and lead the fluid into the section 15 from the upstream side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary flow meter, and more particularly to a rotary flow meter that can be installed in a new or existing pipe line very easily.

[0002]

2. Description of the Related Art Generally, an impeller is provided inside a main body of a flow meter, a fluid flowing in a pipe is collided with the impeller to rotate the impeller, and the rotation of the impeller is detected by a proximity sensor. A rotary flow meter that measures the flow rate is known.

In this type, conventionally, the flowmeter main body is housed in a housing, and this housing is incorporated in the middle of the pipeline.

[0004]

However, the conventional construction has a problem that the construction is difficult and the construction cost is high because the new or existing pipeline is cut midway and the housing is incorporated therein. .. Further, since the structure of the flowmeter itself is complicated, there are problems that the production cost becomes high and the maintenance becomes difficult.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to install the rotary flowmeter in a new or existing pipe line very easily with a simple structure. To provide.

[0006]

In order to achieve the above object, the present invention provides a flowmeter main body fitted in a pipe, and an impeller housing formed in the flowmeter main body and opening downstream. Part, an impeller housed in the impeller storage part and rotatably supported by the wall part of the flowmeter main body, and a perforation hole provided in the peripheral wall of the flowmeter main body for colliding fluid with the impeller and rotating the impeller. And a communication hole for guiding the fluid from the upstream into the impeller storage portion.

[0007]

According to the present invention, the flowmeter main body mounted in the conduit is provided, the impeller is axially supported in the impeller accommodating portion of the flowmeter main body, and the fluid flowing into the impeller through the communication hole is provided. Since the number of revolutions of the rotating impeller is detected by the collision, the structure is extremely simple, and the flowmeter main body can be installed in a new or existing pipe line very easily.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a pipe, and a flowmeter main body 3 is fitted in the pipe 1. The outer shape of the half part 3a of the flowmeter body 3 is formed in a conical shape, and
The outer shape of the other half 3b is formed in a cylindrical shape. Two O-ring grooves 5a, 5b extending in the circumferential direction are formed on the outer circumference of the other half portion 3b, and inside the O-ring grooves 5a, 5b, the inner circumference of the conduit 1 and the outer circumference of the flowmeter body 3 are formed. Two O-rings 7a and 7b are attached to seal the space between them. A step portion 9 is formed on the outer circumference of the other half portion 3b so as to be continuous with the one half portion 3a, and an annular inlet passage 11 is formed between the outer circumference of the step portion 9 and the inner circumference of the conduit 1. .. Reference numeral 13 is a stop ring, and the stop ring 13 is press-fitted into the pipe line 1.

Inside the other half 3b of the flowmeter main body 3, an impeller accommodating portion 15 is formed which opens downstream, and an impeller 17 is rotatably accommodated in the impeller accommodating portion 15. Has been done. As shown in FIG. 2, this impeller 17 is composed of a boss portion 17a and a plurality of blades 17b radially provided on the outer periphery of the boss portion 17a.
The bearing 19 is mounted as shown in FIG. The bearing 19
A mounting bolt 23 having a rectifying cover 21 on its head is fitted to the inner ring portion of the spacer 2.
It is screwed into the female screw hole of the wall portion 25 of the flowmeter main body 3 via 4.

The tip portion 23a of the mounting bolt 23 has an angle γ.
Is formed into a conical shape, and the inner part of the female screw hole of the wall portion 25 that receives the tip is formed into a conical shape with an angle δ. Therefore, according to this embodiment, the relationship of angle γ ≦ angle δ is set, and when the impeller 17 is mounted, the axis of the mounting bolt 23 deviates from the axis of the female screw hole of the wall portion 25. It is designed so that it does not exist.

As shown in FIG. 3, a plurality of communication holes 27, 27 ... 27 for making a fluid collide with each blade 17b of the impeller 17 are formed in the peripheral wall of the stepped portion 9 of the flowmeter main body 3. ing. The communication hole 27 is formed by the inlet passage 11 and the impeller storage unit 1.
5 for communicating the fluid from the upstream side into the impeller housing portion 15.

The shape of the communication hole 27 is as shown in FIG.
The axis center of the step portion 9 is o, the intersection of the inner circumference of the step portion 9 and the portion closest to the axis center o of the communication hole 27 is a, and the outermost portion of the step portion 9 and the axis center o of the communication hole 27 is the farthest portion. , B is the angle formed by the line connecting the points a and o with respect to a predetermined reference line, and β is the angle formed by the line connecting the points b and o with respect to the predetermined reference line.
Then, it is desirable to set the relationship of angle α ≧ angle β.

With this setting, the fluid flowing into the communication hole 27 is rectified in the communication hole 27 while colliding with the peripheral wall thereof, as shown by the arrow, and from there, the impeller housing 1
Since it is discharged into the inside of the impeller 5, it is possible to make a flow without turbulence collide with each blade 17b of the impeller 17. For example, in FIG.
Is an inappropriate example. If the relationship of angle α ≦ angle β is set as described above, the turbulent flow is discharged into the impeller housing portion 15, and the turbulent flow collides with each blade 17b of the impeller 17, which is not preferable.

A through hole 29 is bored in the one half portion 3a of the flowmeter main body 3 in parallel to the axial direction, and one end of a light guide 31 having a length of, for example, about 5 m is inserted into the through hole 29. .. The light guide 31 is led out of the conduit 1, and the other end thereof is connected to an optical sensor (not shown) for detecting the rotation of the impeller 17.

Next, the operation of this embodiment will be described.

The fluid flowing in the conduit 1 flows into the impeller housing portion 15 through the communication hole 27 formed in the flowmeter body 3, where it collides with the impeller 17 and rotates it.
Here, the diameter of the communication hole 27 is d (cm), the number thereof is n,
The flow rate from the communication hole 27 is Q (l / min), the impeller 1
The diameter of 7 is D (cm), the rotation speed of the impeller 17 is N (c / s)
Then, N = 2 × 10 ² · Q / 3 · n · D · d ² (1) When the number of blades 17b of the impeller 17 is m and the pulse of the rotation frequency of the impeller 17 is H (Hz) When ^{H = 2 × 10 2 · Q} · m / 3 · n · D · d 2 ... (2) the expression (2) to expand the Q, Q = (3 · n · D · d 2/2 × 10 2・ M) H (3) When the flow rate is small, the fluid flows out without rotating the impeller 17 or the friction between the impeller 17 and the shaft causes the impeller 17 to reach a certain flow rate. There are phenomena such may not rotate, considering the invalid flow b, Q = aH ± b ... (4) However, a = (3 · n · D · d 2/2 × 10 2 · m) Thus According to this embodiment, the combined force of the forces that act on the rotation of the impeller 17 is directed toward the axis, so the impeller 1
The friction between 7 and the shaft is extremely small, so that the reactive flow rate b is extremely small and the durability is excellent.
Moreover, since the fluid collides with the impeller 17 at a right angle, the energy of the fluid is efficiently converted into the rotational force of the impeller 17,
Even if the flow rate is increased, thrust force is not generated, so
Even if measured at an excessive flow rate, it will have excellent durability. Further, if the number of blades of the impeller 17 is increased, the proportional constant a can be reduced and the measurement resolution can be freely increased, as is apparent from the equation (4).

In this type, unlike the turbine type flow meter, since the thrust force does not act on the impeller 17, the impeller 17 is conventionally made of a Teflon material having a small friction coefficient. Since the rotational imbalance due to the cutting of the impeller 17 remains, when the number of revolutions of the impeller 17 increases, the balance of the rotation deteriorates, which may impair the durability of the impeller 17. Further, in a turbine type flow meter having a large maximum measured flow rate, since the impeller 17 is large, the force acting on the shaft center of the impeller 17 is weak when the flow rate is small, so that the friction between the impeller 17 and the shaft is reduced. There is a possibility that the flow rate increases, and as a result, the invalid flow rate b increases.

Further, in the case where any of the turbine type flow meters as described above is connected by the manufacturer's standard to measure the flow rate of the apparatus, it must be connected to the apparatus piping in accordance with the flow meter. , Therefore, to measure the flow rate of the existing equipment,
In order to use the turbine type flow meter, a major modification of the equipment was required. Further, in the conventional rotary flow meter, when the axis of the flow meter main body 3 and the axis of the impeller 17 deviate from each other, the invalid flow rate b increases and the durability of the impeller 17 decreases. was there.

According to this embodiment, however, the impeller 17 is integrally provided in the flowmeter main body 3 and the O ring is double mounted on the outer circumference of the flowmeter main body 3. It can be installed as is in existing piping.
Further, since the bearing 19 is attached to the shaft portion of the impeller 17, the impeller 17 can be used even in a region where the flow rate of the jet from the communication hole 27 is small.
Can be rotated smoothly. At the same time, impeller 17
The rotational friction of the impeller 17 can be reduced even when the dynamic balance of is insufficient. Therefore, the flow rate Q (l /
min) and the rotational frequency H (Hz) of the impeller 17 at that time, that is, Q = aH ± b, the invalid flow rate b (l /
min) can be reduced.

The tip of the mounting bolt of the impeller 17 is formed in a conical shape (angle = γ), and the end of the female screw hole into which it is screwed is similarly conical (angle = δ, where γ ≦
Since it is formed in δ), it is possible to prevent the axial centers of the two from deviating during the assembling process, so that the perpendicularity between the hole axis of the communication hole 27 and the axial center of the impeller 17 can be improved,
It is possible to reduce the rotational friction, that is, the reactive flow rate b.

When the angle formed by the line connecting the points a and o with respect to a predetermined reference line is α and the angle formed by the line connecting the points b and o with respect to the predetermined reference line is β, Since the relationship of the angle α ≧ the angle β is set, as described above, the swirl is formed in the axial direction of the communication hole 27, and the fluid can vertically act on the blade 17b of the impeller 17.

The inner diameter of the impeller storage portion 15 is D ₁ , and the outer diameter is D
_2, the diameter of the communication hole 27 d, the distance l between the axis and the reference line of the communication hole 27, when the relief amount at the time of processing and l _0, in the inner circumference of the meter body 3, (D _1/2) in · sin α = l- (d / 2) ... (5) outer periphery of the meter body 3, at the time of processing of the _{(D 2/2) · sin} β = l + (d / 2) ... (6) communicating hole 27, as blade does not hit the inscribed circle (D _1/2), the provision of the relief amount _{l 0, l = (D 1} /2) - (d / 2) -l 0 ... (7) as described above , in order to flow the fluid in accordance with the communication hole 27, the α ≧ β ... (8) above relationship, {l- (d / 2) } / D 1 ≧ {l + (d / 2)} / D 2 ... (9) This compound is rearranged for _{D 2, D 2 ≧ {l} + (d / 2)} · D 1 / {l- (d / 2)} ... (10) here, by substituting expression (7) _{Te, D 2 ≧ {(D 1} /2) -l 0} _{D 1 / {(D 1/} 2) -l 0 -d)} ... (11) According to this, the inner diameter D ₁ of the impeller housing portion 15, the diameter d of the communication hole 27, clearance amount during processing By determining l ₀ , the outer diameter D ₂ of the impeller housing portion 15 can be automatically determined, so that the best performance of the flow meter can be derived extremely easily. That is, the flow path of the communication hole 27 is not lengthened unnecessarily, and the pressure loss performance is not sacrificed. According to this, the relationship between the rotational speed H of the impeller 17 and the flow rate Q can be calculated with a more accurate primary It is possible to establish a proportional relationship and improve the measurement accuracy.

Furthermore, according to this embodiment, the impeller 17
In order to prevent the fluid involved in the rotation of the impeller from impeding the rotation of the impeller 17, a flow regulating cover is provided in the lower part of the flow in the vicinity of the impeller 17. According to this, regardless of the viscosity of the fluid, the relationship between the rotational speed H of the impeller 17 and the flow rate Q can be made a more accurate linear proportional relationship, and the measurement accuracy can be further improved. Produce an effect.

FIG. 6 shows another embodiment. According to this, the outer circumference of the flowmeter main body 3 is press-fitted into the inner circumference of the conduit 1 by the interference fit 33. When measuring the flow rate of gas, since a large pressure difference does not occur between the upstream side and the downstream side, the coupling force between the conduit 1 and the flowmeter main body 3 is not so required.

However, when measuring the flow rate of the liquid, since a considerable pressure difference occurs between the upstream and the downstream, there is a risk that the flowmeter main body 3 will flow downstream if there is no significant coupling force between the two. Occurs. In the above embodiment, the stop ring 1
However, in this embodiment, the stop ring 13 is omitted and the outer circumference of the flowmeter body 3 is press-fitted.

[0027]

As is apparent from the above description, according to the present invention, a commercially available pipe can be used as a conduit,
Significant price reduction can be achieved. In the case of an existing device, it may be designed according to the pipeline being used, and this flow meter can be provided without major structural changes.
In a device such as a compressor whose one end is open, the flow rate can be measured very easily by inserting this flow meter into the suction port. Q = aH ± b
In the conversion formula of the flow meter of, the effective flow rate b can be reduced,
The measurement accuracy can be improved and the maximum flow rate /
The rangeability, which is the ratio of the minimum flow rate, can be greatly improved. Further, since the rotational balance of the impeller is stably maintained by the bearing, the durability can be greatly improved and the maximum measurable flow rate can be increased. Since the accuracy of assembling the shaft center of the impeller is improved, rotational friction can be reduced, the durability of the impeller can be improved, and the invalid flow rate b can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a rotary flow meter according to the present invention.

FIG. 2 is a view of the rotary flow meter of FIG. 1 viewed from an impeller storage section.

FIG. 3 is a cross-sectional view showing a communication hole formed in the flowmeter body.

FIG. 4 is a sectional view showing an appropriate shape of a communication hole.

FIG. 5 is a cross-sectional view showing the shape of an inappropriate communication hole.

FIG. 6 is a vertical sectional view showing another embodiment of the rotary flow meter.

[Explanation of symbols]

 1 Pipeline 3 Flowmeter Main Body 15 Impeller Storage 17 Impeller 17b Impeller 19 Bearing 21 Rectifying Cover 23 Mounting Bolt 27 Communication Hole 31 Light Guide

Claims (1)

Claim: What is claimed is: 1. A flowmeter main body which can be fitted in a pipe line, an impeller storage portion formed in the flowmeter main body and opening toward the downstream side, and a storage in the impeller storage portion. And an impeller axially supported on the wall of the flowmeter main body, and a fluid from the upstream side is provided in the peripheral wall of the flowmeter main body in order to collide the fluid with the impeller and rotate the impeller. A rotary flowmeter, comprising: a communication hole that leads into the storage section. 2. In the shape of the communication hole, the axial center of the flowmeter main body is o, the intersection point of the inner circumference of the flowmeter main body and the portion closest to the axial center o of the communication hole is a, and the outer circumference of the flowmeter main body. The intersection point with the portion farthest from the axial center o of the communication hole is b, the angle formed by the line connecting the points a and o to a predetermined reference line is α, and the line connecting the points b and o is the reference line. The rotary flow meter according to claim 1, wherein a relationship of angle α ≧ angle β is set, where β is an angle formed with respect to the rotary flow meter.