JPH0725633Y2 - Bend flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a bend flowmeter for measuring a fluid flow rate based on a differential pressure of fluid pressure detected at two points in a flow path in a bend.

[Conventional technology]

The basic structure of a conventional bend flow meter is disclosed in the flow rate measurement handbook issued on July 10, 1979, and its structural example is specifically shown in FIG. As shown in the figure, the conventional bend flowmeter is provided on each of the diaphragms 4 and 5 by setting pressure detection points 2 and 3 by providing openings in the outer and inner portions of the bend wall 1 which face each other. Pipe lines 8, which are separately installed from the pressure detection points 2 and 3 to the pressure receiving ports 6 and 7,
9 are connected to each other, and the pipe lines 8 and 9 are formed by fluid introduction pipes extending perpendicularly to the bend wall 1. The diaphragms 4 and 5 constitute a part of the differential pressure gauge, and the pressure receiving ports 6 and 7 are also the pressure receiving ports of the differential pressure gauge. 10 and 11 are valves for supplying and discharging cleaning water.

According to such a bend flow meter, the pressures P ₁ and P _{2 of} the fluids introduced into the fluid chambers of the diaphragms 4 and 5 through the pipes 8 and 9 are set at two pressure detection points in the in-bend flow passage F. It corresponds to the pressure at 2 and 3, and the flow rate is obtained from the differential pressure P ₁ -P ₂ .

[Problems to be solved by the invention]

However, the conventional bend flowmeter has an upslope in the range from the pressure detection point 2 set on the outer side of the bend wall 1 to the pressure receiving port 6, and thus the flow path in the bend. There is a problem that a fluid flowing in F, for example, bubbles contained in water easily enter the conduit 8 from the pressure detection point 2, and this problem causes the following inconvenience. That is, once the air bubbles enter the pipe line 8, the air bubbles are trapped inside the pipe line 8 or in the fluid chamber of the diaphragm 4, and if such air bubble confinement occurs, it is unacceptable in the differential pressure gauge. Accurate differential pressure (P ₁ -P ₂ ) cannot be obtained due to measurement error, and when flow rate measurement is repeated, different flow rate values are required due to bubble closure even under the same conditions. Was occurring.

The present invention has been made in view of the above problems, and an object thereof is to provide a bend flowmeter in which bubbles are unlikely to enter a conduit extending from a pressure detection point set in a flow path in a bend to a pressure receiving port of a differential pressure gauge.

[Means for solving problems]

In the bend flowmeter of the present invention, each of the conduits, which are individually guided from the pressure detection points set at two locations in the flow path in the bend and respectively connected to the two pressure receiving ports of the differential pressure gauge, have the above-mentioned pressure receiving ports. Is set in a horizontal state or a state having an upslope toward the pressure detection point.

[Action]

According to the bend flow meter with this configuration, each of the separate pipelines connecting the two pressure detection points and the two pressure reception ports is from the pressure detection port to the pressure detection point in the range from the pressure detection point to the pressure reception port. Since it has a horizontal or upslope, bubbles with a smaller specific gravity than fluids such as water do not easily enter the respective pipelines, and even if those bubbles enter the pipelines, they flow along the upslope of the pipelines to the flow path in the bend. Easy to get out.

〔Example〕

FIG. 4 shows the bend flowmeter of the present invention in principle. Pressure detection points 2 and 3 and pressure receiving ports 6 and 7 of diaphragms 4 and 5.
Each of the separate pipelines 8 and 9 connecting to and has an upward slope from the pressure receiving ports 6 and 7 to the pressure detecting points 2 and 3 in the range from the pressure detecting points 2 and 3 to the pressure receiving ports 6 and 7. is doing. Since other configurations are similar to those of the conventional example described in FIG. 6, the same reference numerals are given and detailed description will be omitted. θ ₁ represents the inclination angle of the conduit 8 and θ ₂ represents the inclination angle of the conduit 9, and may be θ ₁ = θ ₂ or θ ₁ ≠ θ ₂ .

According to such a bend flow meter, the flow rate can be obtained by the same principle as that explained in the conventional example of FIG. Then, even if the fluid flowing in the in-bend flow path F, for example, water contains bubbles, the pipelines 8 and 9 have the upward gradient as described above, so that the bubbles are It is difficult to enter 9, and even if it enters, it is easy to go out to the flow path F in the bend along the ascending slope. In addition, in FIG. 4, the conduits 8 and 9 may be horizontal.

By the way, when a new pump is installed in a dirty water tank or the like, the pump is actually operated to check the pumping capacity of the pump, and the flow rate of water flowing through the discharge pipe is inspected at that time. In such an inspection, the bend flow meter of the present invention can be preferably used.

FIGS. 1 to 3 show an example of a bend flow meter in which a discharge pipe 20 of a pump made of an arcuate curved pipe is used as a bend, and a rotary shaft 21 of a vertical shaft pump is inserted into the discharge pipe 20. There is. In addition, small holes 22 and 23 used as pressure detection points are formed at opposite portions of the outer portion and the inner portion of the discharge pipe 20.

A down pipe 26 is vertically connected to the short pipe 24 drawn out from one of the small holes 22 via an elbow 25, and a straight pipe 28 is connected to the down pipe 26 via an elbow 27. The tip of 28 is connected to the pressure receiving port 30 of the diaphragm 29. An air reservoir 31 is connected to the upper part of the fluid chamber of the diaphragm 29 via a connecting pipe 32. V ₁ is a valve interposed in the connecting pipe 32. A drain drain valve V ₂ is provided below the fluid chamber of the diaphragm 29.

A down pipe 37 is vertically connected to the short pipe 35 drawn out from the other small hole 23 via an elbow 36, and a straight pipe 39 is connected to the down pipe 37 via an elbow 38. The tip of 39 is connected to the pressure receiving port 41 of the diaphragm 40. An air reservoir 42 is connected to the upper part of the fluid chamber of the diaphragm 40 via a connecting pipe 43. V ₃ is a valve interposed in the connecting pipe 43. A drain drain valve V ₄ is provided below the fluid chamber of the diaphragm 40.

Reference numeral 46 denotes a differential pressure converter, which plays a role of converting the differential pressure of each pressure obtained by the diaphragms 29, 40 into a flow rate. The differential pressure converter 46 and the diaphragms 29, 40 are used to measure the differential pressure. Is configured.

50 is a connecting pipe connecting the two straight pipes 28 and 39, 51 is a wash water inlet pipe connected to the connecting pipe 50, and the wash water inlet pipe 51 is connected to a wash water source 52. V ₅ is a valve interposed in the connecting pipe 50, and V ₆ is a valve interposed in the wash water inlet pipe 51.

Here, the small hole 22, the short pipe 24, the elbow 25, and the falling pipe described above are provided.
The pipe line formed by 26, the elbow 27 and the straight pipe 28 corresponds to the pipe line 8 described in FIG. 4, and also includes the small hole 23, the short pipe 35, the elbow 36, the falling pipe 37, the elbow 38 and the straight pipe. The pipe formed by the pipe 39 corresponds to the pipe 9 described in FIG. 4, and each portion in the range from the pressure receiving ports 30 and 41 to the openings of the small holes 22 and 23 which are pressure detection points is Bubbles contained in the water flowing through the discharge pipe 20 that is set in a state having an upslope or in a horizontal state are hard to enter, and even if they enter, they are easy to come out. In particular, since the falling pipes 26, 37 are interposed in the middle of the pipeline, bubbles are generated in the falling pipes 26, 3
Although it may enter up to the starting point of 7, it rarely passes through the falling pipes 26 and 37. Nevertheless, the bubbles that have entered the fluid chambers of the diaphragms 29, 40 escape to the inside of the air pools 31, 42, so that an unacceptable conversion error does not occur in the differential pressure converter 46.

Reference numerals 60 and 61 denote Y-shaped strainers, which are interposed in the straight pipes 28 and 39, and serve to take out solid foreign matters such as dust mixed in the water in front of the diaphragms 29 and 40 to the outside of the pipeline. If such Y-shaped strainers 60 and 61 are installed, it is possible to prevent solid foreign matter from entering the diaphragms 29 and 40. Therefore, the weight of the solid foreign matter causes an unacceptable conversion error. There is no. In addition,
Instead of the Y-shaped strainers 60 and 61, a dust reservoir for accumulating solid foreign matter outside the pipeline may be installed.

In FIG. 5, pressure receiving ports 30 and 41 are provided above the fluid chambers of diaphragms 29 and 40, and straight pipes 28 and
This is an example in which vertical falling portions 28a and 39a formed at the tip of 39 are connected. In this way, the vertical falling portions 28a, 39a prevent bubbles from entering the fluid chambers of the diaphragms 29, 40, and even if they enter, they immediately go out through the falling portions 28a, 39a. There is. Therefore, if it is set as shown in FIG. 5, the same operation is performed without providing the fall pipes 26, 37 described in FIGS. 1 to 3, and the air reservoirs 31, 42 and the valves V ₁ , There is no need to provide V ₂ .

[Effect of device]

The bend flowmeter of the present invention makes it difficult for bubbles contained in a fluid such as water to enter into each of the separate pipelines that connect the two pressure detection points and the two pressure receiving ports, and the bubbles that have once entered the pipelines. Is likely to flow into the flow path in the bend, it is less likely that air bubbles will be trapped inside the pipe and the flow rate measurement error will increase, and an accurate flow rate value can be obtained, and when flow rate measurement is repeated. Under the same conditions, a flow rate value with less variation compared to the conventional example can be obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment in which the bend flow meter of the present invention is constructed by utilizing a discharge pipe of a pump, FIG. 2 is a front view of the same embodiment, and FIG. 3 is a view of the same embodiment. FIG. 4 is a plan view, FIG. 4 is a cross-sectional view showing another embodiment of the present invention, and FIG. 5 is a partially cutaway side view showing an example of connection between a pipeline and a pressure receiving port of a differential pressure gauge.
FIG. 6 is a sectional view of a conventional example. F …… Bend flow path, 2,3 …… Pressure detection point, 4,5 …… Diaphragm, 6,7 …… Pressure receiving port, 8,9 …… Pipe line, 22,23…
… Small hole, 24,35 …… Short pipe, 25,36 …… Elbow, 26,37 ……
Fall tube, 27,38 …… Elbow, 28,39 …… Straight tube,
29,40 …… Diaphragm (component of differential pressure gauge), 30,41…
… Pressure receiving port

Front page continuation (72) Inventor Sohei Umezawa 1-1-1, Nakamiya Oike, Hirakata-shi, Osaka Inside Kubota Iron Works Hirakata Factory (72) Inventor Masahiko Akiyama 1-1-1, Nakamiya Oike, Hirakata-shi, Osaka Kubota Iron Works Co., Ltd. Hirakata Works (72) Creator Koichi Nishimura 1-1-1 Nakamiya Oike, Hirakata City, Osaka Prefecture Kubota Iron Works Co., Ltd. Hirakata Works (56) References: 54-92761 (JP, U) )

Claims (1)

[Scope of utility model registration request] 1. A bend flow meter, wherein pipes respectively provided separately from pressure detection points set at two points in a flow path in a bend are separately connected to two pressure receiving ports of a differential pressure gauge, A bend flowmeter characterized in that each of the pipes is set in a horizontal state or a state having an upward slope from the pressure receiving port toward the pressure detection point.