JPH095131A - Orifice flow meter - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an orifice flow meter for an agricultural pipeline, which is suitable for agricultural water (fluid) containing foreign matters such as bubbles, powder, and dust. [Structure] The orifice flow meter of the present invention can measure the flow rate with practical accuracy even for agricultural water containing a large amount of bubbles and dust. Further, it is advantageous because it has a simple plate cross-section without edges. The following configuration is intended for such purposes. A plate-shaped circular orifice plate 2 is formed in the pipe, and the fluid distribution ports 3 and 6 are provided on the upstream side and the downstream side of the circular orifice plate.
Is an orifice flow meter comprising a pipe main body 1 provided with a flow meter and a flow meter for measuring the flow rate of the branched fluid via the fluid flow dividing port, and the thickness of the circular orifice plate is 2 of the pipe inner diameter.
A flowmeter for measuring the flow rate of the split fluid is formed by setting the opening area ratio of the flow passage to be approximately 0.6 to approximately 0.8, which is inserted and fixed in the lateral direction of the pipe line at a rate of less than or equal to The flowmeter 5 is characterized by having no movable part in the flow path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orifice flow meter for an agricultural pipe channel suitable for agricultural water (fluid) containing foreign matters such as bubbles, powder and dust.

[0002]

2. Description of the Related Art Heretofore, there has been no orifice flow meter suitable for an agricultural pipe channel containing foreign matters such as bubbles, powder and dust.
Further, for example, as a throttle mechanism, an orifice plate is widely known, and among them, a concentric circular orifice is easy to process and is easy to handle, and thus is used as the most general mechanism. However, since the orifice hole has the same central axis as the central axis of the pipeline and has a uniform throttling effect on the flow, it contains air bubbles and dust like an agricultural pipeline, and does not contain powder or dust. When foreign matter such as dust was included, the foreign matter was accumulated and accumulated on the upstream side, and accurate measurement could not be performed. In addition, a flowmeter having a movable part that divides the flow from the upstream side of the orifice to the downstream side and measures the divided flow rate has been used.

[0003]

Since the conventional orifice is not provided with measures against the inflow of foreign matter and the like, foreign matter is deposited on the upstream side, and an orifice in which foreign matter is hard to be deposited has been required. In addition, since the split flow meter also has a movable part in the flow path, there is a problem such as clogging of foreign matter.

It is an object of the present invention to provide an orifice flow meter having a structure in which foreign matter does not accumulate on the upstream side at the orifice and does not become clogged even if foreign matter enters the shunt flow meter.

[0005]

In order to achieve the above-mentioned object, a pipe in which a plate-shaped circular orifice plate is formed in a pipe line and fluid distribution ports are provided upstream and downstream of the circular orifice plate. An orifice flow meter comprising a channel body and a flow meter for measuring the flow rate of a split fluid via the fluid diversion port,
The aforesaid circular orifice plate has a thickness of 20% or less of the inner diameter of the conduit, is inserted and fixed in the lateral direction of the conduit, and has an opening area ratio of the passage of about 0.6 to about 0.8. The flowmeter for measuring the flow rate of the split-flow fluid, which is formed as described above, is a flowmeter having no movable part in the flow path, which is an orifice flowmeter.

The plate-shaped circular orifice plate may have a plate cross section that does not form an edge.

Further, the flow meter for measuring the flow rate of the split fluid may be an electromagnetic flow meter.

[0008]

With the above structure, the opening area ratio β is set to about 0.6 to about 0.8 from the lateral direction of the conduit body 1 (the direction orthogonal to the fluid flow direction as shown in FIG. 2). A circular orifice plate 2 having a thickness of 20% or less of the inner diameter D of the conduit body 1 inserted in the
Since upper and lower shunt channels 4 and 7 for the fluid are provided via 6 and a flow meter 5 having no movable part in the channel is provided between the shunt tubes 4 and 7 on the upper and lower sides, The main body fluid passing through the circular orifice plate 2 and the split flow fluid passing through the flowmeter 5 having no movable portion flow from the upstream side to the downstream side. At that time, the split flow rate is measured by the flow meter 5 having no movable part, and the flow rate of the mainstream fluid is measured by the product of the conversion coefficient and the flow rate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings, in which 1 is a main body of a main stream, and the main body 1 of the conduit has an opening area ratio β of about 2/3 from its lateral direction. A plate-shaped circular orifice plate 2 having a thickness of 20% or less of the inner diameter D of the conduit body 1 is inserted and fixed by welding.

Reference numeral 3 denotes an upstream fluid distribution port provided on the upstream side (introduction side) of the circular orifice plate 2 inserted in the pipe body 1, and the upstream side of the upstream fluid distribution port 3 is provided. To the flowmeter 5 having no movable parts, which is connected to the other end of the upstream side branch flow pipe 4 and is connected to the branch flow pipe 4 of FIG. Is guided.

Reference numeral 6 denotes a downstream fluid distribution port provided on the downstream side (discharging side) of the circular orifice plate 2 inserted in the conduit body 1, and the downstream fluid distribution port 6 has a downstream side. Of the flowmeter 5 having no movable part is connected to the other end via the branching flow pipe 7 on the downstream side, and the fluid discharged from the flow meter 5 having no movable part is It is guided to the conduit main body 1.

Next, the flow rate measurement will be described based on the experimental data of the present invention.

The flow rate by the circular orifice plate is calculated by the following equation.

[0014] FIG. 3 is a diagram showing the relationship between the opening area ratio β and the structural coefficient α of the missing circular orifice plate 2 with and without edges in the missing circular orifice plate 2. This means that the fluid resistance increases when passing through the orifice, and the structural coefficient α also decreases as the opening area ratio β decreases. In the present invention, the reason why the circular orifice plate 2 having a simple shape, which is a plate cross section without an edge, is adopted is that it is easy to manufacture and the fluid resistance can be reduced.

FIG. 4 shows the pressure loss (meter water column) due to the missing circular orifice plate 2, and as a matter of course, when the opening area ratio β due to the missing circular orifice plate 2 is about 0.5 or less. Since it was found that the pressure loss suddenly increased,
It will be manufactured with an appropriate opening area ratio β, and practically,
An opening area ratio β of about 2/3 with a small pressure loss was adopted.

FIG. 5 shows the relationship between the thickness t of the plate piece of the missing circular orifice plate 2 and the structural coefficient α when the opening area ratio β is 2/3. The thickness of the missing circular orifice plate 2 is shown in FIG. Is 20% or less of the inner diameter D of the conduit body 1, the structural coefficient α is constant, and the thickness of the circular orifice plate 2 may be an appropriate value of 20% or less of the inner diameter D of the conduit body 1. It is shown that.

FIGS. 6 and 7 are instrumental performance diagrams of the orifice flow meter of the present invention. In this example, the opening area ratio β = 2/3
Then, an electromagnetic flow meter with a diameter of 50 mm was used as the diversion flow meter, and in FIG. 6, the diameter of the pipe body is 500 mm, and FIG.
[Fig. 3] is an instrumental difference performance diagram in which the diameter of the conduit body is 700 mm.

[0018]

EFFECTS OF THE INVENTION Since the present invention is a circular orifice flow meter inserted from the lateral direction as described above, even if it is agricultural water containing a large amount of bubbles and dust, the flow rate can be controlled with practical accuracy. You can measure.

Further, since the circular orifice plate of the present invention has a simple plate cross section without edges, it has a simple structure and is easy to manufacture. In addition, since a flowmeter with no moving parts is provided in the branch flow channel, there is no trouble such as stopping due to dust and the like, and the flow rate of the main pipe can be measured with a flowmeter with a significantly smaller diameter than the pipe diameter.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an orifice flow meter according to the present invention.

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a diagram showing a relationship between an opening area ratio β and a structure coefficient α.

FIG. 4 is a diagram utilizing a relationship between a flow rate of a conduit and a pressure loss due to a circular orifice plate.

FIG. 5 is a diagram showing the relationship between the thickness t of a plate used as an open-circle orifice plate and the structural coefficient α.

FIG. 6 is an instrumental performance diagram of an orifice flow meter with a diameter of 500 mm according to the present invention.

FIG. 7 is an instrumental performance diagram of an orifice flow meter having a diameter of 700 mm according to the present invention.

[Explanation of symbols]

 1 Pipe Main Body 2 Missing Orifice Plate 3 Fluid Distribution Port on Upstream Side 4 Distribution Channel on Upstream Side 5 Flowmeter without Moving Parts 6 Fluid Distribution Port on Downstream Side 7 Distribution Channel on Downstream Side

Claims (3)

[Claims] 1. A pipe main body in which a plate-shaped circular orifice plate is formed in a pipe, and fluid distribution ports are provided on the upstream side and the downstream side of the circular orifice plate, and the fluid distribution port. An orifice flow meter comprising a flow meter for measuring the flow rate of a split flow fluid, wherein the circular orifice plate has a thickness of 20% or less of an inner diameter of the conduit, is fixed by inserting from a lateral direction of the conduit, The flowmeter, which is formed so that the opening area ratio of the passage is about 0.6 to about 0.8, and which measures the flow rate of the split-flow fluid is a flowmeter having no movable part in the flow passage. Orifice flow meter to. 2. The orifice flow meter according to claim 1, wherein the plate-shaped circular orifice plate has a plate cross section that does not form an edge. 3. The orifice flowmeter according to claim 1, wherein the flowmeter for measuring the flow rate of the split fluid is an electromagnetic flowmeter.