JPH02302624A - Cone type electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To reduce the dispersion in performance by providing a fluid circuit and a magnetic circuit at the upper and lower parts of a straight line connecting electrodes, and providing straightening vanes at the upstream side and the downstream side of a coil case and a coil scale stopper. CONSTITUTION:Plannar straightening vanes 24 and 25 are provided on the upstream side and the downstream side of a coil case 20 and a coil case stopper 21. Electrodes are provided at a flow-rate measuring pipe 2 which is orthogonal to the axial centers of the case 20 and the stopper 21 and the flowing direction of fluid. A fluid to be measured flows through a path between the pipe 2 and a cone pipe 19. An induced voltage generated in the fluid to be measured is taken out through the electrodes. Since the straightening vanes 24 and 25 are provided on the upstream side and the downstream side of the case 20 and the stopper 21, vortexes are not generated in the downstream, and the dispersion in performance can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in cone-type electromagnetic flowmeters.

[Conventional technology]

As shown in Fig. 7, a cone 1 which is spindle-shaped as a whole and has a circular cross section perpendicular to the flow is provided coaxially with the flow rate measurement pipe 2, and the cone 1 is placed along the outer diameter of the cone 1 as appropriate. An internally magnetic cone with magnetic poles A and B separated by the diameter of the cone 1 in a circumferential angle range, and a magnetic generator 5 with an excitation coil 4 wound around a core 3 between the magnetic poles A and B. type electromagnetic flowmeter is well known (for example, Japanese Utility Model Publication No. 59-17233).
Publication No. 2).

The concrete structure of the conventional cone type electromagnetic flowmeter is shown in FIGS. 7 and 8.

In this prior art, in order to hold the cone l concentrically with the flow rate measurement pipe 2, holder cones 6.7 are provided at the upstream and downstream ends of the cone 1, and these holders hold the cone 1 at both ends. was supporting. An outer vibrator 8 was provided surrounding the flow rate measuring pipe 2, and a flange 9.10 was fixed to the end of the outer pipe 2.

A lead wire 11 that supplies exciting current to the coil 4 placed in the center of the cone L is connected to one end of the cone (the right end in FIG. 7).
It passed through the rib 7a of the holder cone 7 and was drawn out to the outside of the flow rate measuring pipe 2.

In order to maintain watertightness between the coil 4 and the lead wire, a sealing structure with six O-rings was required.

The first and second O-rings 12 and 13 are provided at the sealing portion between the spindle-shaped portions at both ends of the cone 1 and the holder cones 6 and 7, and the third and fourth O-rings 14 and 15 are provided at the sealing portion between the spindle-shaped portions at both ends of the cone 1 and the holder cones 6 and 7. The fifth and sixth O-rings 16 and 17 are provided between the holder cone 6 and the flange 90 and between the holder cone 7 and the flange 1.
0 and 0, respectively.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, as many as six O-rings 12 to 17 are required to keep the lead wire 11 watertight, which not only complicates the structure but also requires the groove machining of the O-ring. There was a problem in that it was necessary to make grooves at six locations, and the groove machining required precision.

Furthermore, the holder cone that supports the cone 1 is heavy and not only weighs down the flowmeter, but also requires precision machining, resulting in high manufacturing costs.

In view of the above, it is an object of the present invention to propose a cone-type electromagnetic flowmeter that can solve these problems.

(Means for Solving the Problems) In order to achieve the above object, the cone electromagnetic current meter of the present invention is characterized by having the following structural requirements (a) to (j).

(a) A cylindrical cone pipe (19) having an outer diameter smaller than the inner diameter of the flow rate measurement pipe (2) and arranged concentrically with the flow rate measurement pipe (2).

b) Coil case end (20d) made of magnetic material
, one end of which is watertightly closed, the total length is smaller than the inner diameter of the flow rate measuring pipe (2), and the cone pipe (
Cylindrical coil case (20) larger than the outer diameter of 19)
.

(c) The coil case QO has one end closed by the coil case end (20d) located on the outer periphery of the cone pipe (19), and the other end protruding from a hole made in the diameter direction of the cone pipe. It traverses the flow path and further penetrates the flow rate measuring pipe (2) in a watertight manner.

(d), one end thereof fits into the closed end of the coil case (20), the outer diameter thereof is the same as the outer diameter of the coil case (20), and the other end is arranged on an extension line of the coil case 12Φ; passes through the flow rate measurement pipe (2) in a watertight manner.
Cylindrical coil case stopper (21).

(e) Magnetic poles (A) and (B) are respectively arranged in the cone pipe (19) surrounding the pair of holes provided in the cone pipe (19).

(f) Inside the coil case (20), an iron core (3) is provided, one end of which fits into the coil case end (20d).
), the coil (4) wound around this core (3), and the core (
3) A core end made of magnetic material that fits into the other end (3)
a), and the coil case end (20d) and core end (3a) are connected to the magnetic poles (B) and (A), respectively.
It is placed opposite to.

(Powder, cone heads (22) and (23) with bullet-shaped tips fitted on the upstream and downstream sides of the cone pipe (19).

(c) A plane that includes the axes of the coil case (20) and the coil case stopper (21), and the flow rate measurement pipe (2)
Plate-shaped current plates (24) and (25) are provided on the upstream and downstream sides of the coil case (20) and the coil case stopper (21) in the fluid passage between the coil case (20) and the cone pipe (19).
).

(i) The current plates (24) and (25) are fixed to the flow meter side pipe (2) and the cone heads (22) and (23), respectively, and constitute a part of the earth rib.

(j) Electrodes (26) and (27) are provided on the flow rate measurement pipe in a direction perpendicular to the axes of the coil case (20) and the coil case stopper (21) and the flow direction of the fluid.

[Effect]

The cone pipe (19) is supported by a coil case (20) and a coil case end (20d), as well as cone heads (22), (23) and current plates (24), (25).
) and is fixed concentrically with the flow rate measurement pipe (2), and the wave meter side fluid flows through the passage between the flow rate measurement pipe (2) and the cone pipe (19).

Cone heads (22) and (23) are cone pipes (19)
) to form the entire cone into a streamlined shape to keep fluid resistance low.

Coil case (20) and coil case stopper (21)
rectifying plates (24) arranged upstream and downstream of the
, (25) prevent the fluid from generating vortices downstream of the coil case (20) and the coil case stop (21).

The magnetic flux from the magnetic generator consisting of the iron core 3 and coil 4 is
From iron core 3 to coil case end (20d), magnetic pole (B
) facing the fluid system side pipe (2) across the fluid passage.
, it makes itself a magnetic path, crosses the fluid path again from the surface facing the magnetic pole (A) on the opposite side, flows from the magnetic pole (A), the core end (3a) to the iron core (3), and generates a magnetic field in the fluid path. .

The induced voltage generated in the fluid flowing through the fluid passage is applied to the electrode (26).
, (27).

Current plates (24) and (25) are installed upstream and downstream of the coil case (20), which has a cylindrical outer shape, and the coil case stopper (21).
) are provided, so even if the fluid flows in the forward and reverse directions, no vortices are generated downstream of the coil case (20) and the coil case stopper (21).

In addition, since the fluid flowing on both sides of the plane containing the straight line connecting the electrodes (26) and (27) and the center line of the flow rate measurement pipe (2) and the magnetic field are distributed symmetrically on the plane, variations in performance may occur. It's also small.

〔Example〕

In Figures 1 to 3, 2 is a flow rate measuring pipe made of a soft magnetic material, 3 is an iron core, and 4 is an excitation coil wound around this iron core, and the iron core 3 and coil 4 constitute a magnetism generator. .

19 is a cone pipe concentric with the flow rate measuring pipe 2, and 20 is a small diameter cylindrical coil case, the lower end of which is watertightly closed by a coil case end 20d made of a magnetic material.

The detailed structure of the coil case 20 is shown in FIG.

The coil case 20 is constructed by welding a short cylinder 20b made of a magnetic material to the upper end of a non-magnetic cylinder 20c closed by welding a coil case end 20d to the lower end, and further welding a cylinder 20a made of a non-magnetic material to the upper end of the short cylinder 20b. As a whole, a cylindrical coil case with a bottom is formed, and the upper end thereof is open. Each cylinder 20a, 20b, 20c and the coil case end 20d are welded to maintain watertightness. The entire length of the coil case 20 is longer than the outer diameter of the cone pipe 19 and smaller than the inner diameter of the flow rate measurement pipe 2.

The purpose of setting such a length is to allow the open end of the coil case 20 fitted to the cone pipe 19 to be penetrated and welded to the flow rate measurement pipe 2, that is, to make it a length that can be assembled.

Again in Figures 1 to 3, A and B are magnetic poles spot welded to the upper and lower inner circumferential surfaces of the central part of the cone pipe, respectively, and both of these magnetic poles have holes that penetrate the cone pipe in the vertical direction simultaneously. The pipe 20 is fitted through this hole.

The coil case end 20d is fitted with the magnetic pole B so that its lower end is located below the outer circumference of the icon pipe, and the cylinder 2
0b is fitted into the magnetic pole A. The upper part of the coil case 20, that is, the cylinder 20a crosses the fluid passage in the vertical direction, and its upper end passes through the flow rate measurement pipe 2.
are welded together to maintain watertightness. The upper end of a non-magnetic coil case stopper 21 fits into the lower end of the coil case 20, that is, the lower end of the coil case end 20d. It penetrates through the tube, protrudes downward, and is welded to the flow rate measuring pipe 2 in a watertight manner.

22 and 23 are cone heads with bullet-shaped tips that are fitted and fixed to the upstream and downstream ends of the cone pipe 19;
Reference numerals 24 and 25 indicate rectifying plates, the plate surfaces of which are arranged on a plane that includes the axes of the coil case 20 and the coil case stopper 21 and the axis of the flow rate measurement pipe, that is, a vertical plane that includes the center of the flow rate measurement pipe 2. and are fitted and fixed to the cone heads 22 and 23, respectively. In FIG. 3, one of the rectifying plates 25
The center portion 25a of the cone head is shown fitted into the cone head 23a.

FIG. 4 shows the assembly relationship between the cone pipe 19, the coil case 20, the cone head 23, and the current plate 25. After the pin 28 fits the center part 25a of the current plate 25 into the slit 23a of the cone head 23, the pin 28 is inserted through the hole 23b of the cone head 23 and the hole 25b of the cone head 25 so that both can be removed. Insert.

Ends 24c and 25c of the rectifying plates 24 and 25 are welded and fixed to the upstream end of the flow rate measuring pipe 2, respectively, and are electrically grounded to function as earth ribs.

The rectifying plates 24, 25 are made of non-magnetic stainless steel, and by welding the ends 24c and 25c to the ends of the flow rate measuring pipe 2, the fixing strength of the entire cone, such as the cone head 22, 23 and the cone pipe 19, is increased. There is.

Reference numerals 26 and 27 are a pair of electrodes arranged on the diameter of the flow rate measuring pipe perpendicular to the axis of the coil case 20, and are made of stainless steel.

- The surfaces of the cone pipe 19, coil case 20, coil case stopper 21, and flow rate measuring pipe that come into contact with the fluid are covered with a coating film. The portion indicated by the reference numeral 29 in FIG. 2 is a fluid passage. 11 is a lead wire that supplies exciting current to the coil 4. 30 is an outer pipe, and 31 is a flange.

In the embodiments shown in FIGS. 1 and 2, the electronic circuit section that amplifies and arithmetic-processes the induced voltage generated at the electrodes 26 and 27 and displays the results is omitted and is not shown.
Furthermore, in the embodiments shown in FIGS. 1 to 5, the outer diameter of the coil 4 is set relatively small compared to the prior art shown in FIGS. 7 and 8, and as a result, the diameter of the coil case 20 is reduced. ing.

Therefore, the water pressure applied to the coil case 20 is reduced as a whole, and the thickness of the cylinder of the coil case 20 can be made thinner.

(Effects of the Invention) Since the iron core 3 and coil 4 are housed in the sealed coil case 20 with one end open, the coil lead wire can be drawn out from this opening. Therefore, an O-ring is required to make the lead wire watertight. It is no longer necessary to use many
The structure is simple, eliminating the need for precision machining such as OIJ song grooves, reducing manufacturing costs. In addition, the watertight structure is highly reliable.

Furthermore, since the volume of the part that requires a watertight structure has been reduced from a few folds in the conventional technology to several hundred times smaller, the wall thickness of the pressure-receiving part of the watertight structure can be reduced, which reduces material costs and weight. We were able to reduce it. In addition, because the fluid circuit and magnetic circuit are symmetrical above and below the straight line connecting the electrodes, there is little variation in performance.
In addition, since the rectifying plates are provided upstream and downstream of the coil case and the coil case stopper, Karman vortices will not occur, and in this respect, effects such as no risk of deterioration of meter performance can be expected.

[Brief explanation of drawings]

1 to 5 show examples of the present invention, in which FIG. 1 is a vertical cross-sectional view taken along a plane including the center line of the flow rate measuring pipe, FIG. 2 is a vertical cross-sectional view perpendicular to the flow rate measuring pipe, and FIG. Figure 3 is a sectional view taken along the line ■-■ in Figure 1, Figure 4 is an exploded perspective view explaining the assembly relationship of the cone pipe, cone head, rectifying plate, etc., Figure 5 is a longitudinal cross-sectional view of the coil case, and Figure 6. 1 is a vertical cross-sectional view showing the basic structure of a conventional cone-type electromagnetic flowmeter, and FIGS. 7 and 8 are vertical cross-sectional views showing the specific structure of the conventional technology, respectively.
FIG. 2 is a diagram corresponding to the cross section of FIG.

Claims (1)

[Claims] 1. A cone-type electromagnetic flowmeter having the following structural requirements (a) to (j). (a) A cylindrical cone pipe (19) having an outer diameter smaller than the inner diameter of the flow rate measurement pipe (2) and arranged concentrically with the flow rate measurement pipe (2). (b) Coil case end made of magnetic material (20d
), one end of which is watertightly closed, and the total length of which is smaller than the inner diameter of the flow rate measuring pipe (2) and larger than the outer diameter of the cone pipe (19).
). (c) The coil case (20) has one end closed with the coil case end (20d) and a cone pipe (19).
), and the other end protrudes from a hole made in the diametrical direction of the cone pipe, crosses the flow path, and further penetrates the flow rate measurement pipe (2) in a watertight manner. (d), one end thereof fits into the closed end of the coil case (20), the outer diameter thereof is the same as the outer diameter of the coil case (20), and the coil case (20) is arranged on an extension line of the coil case (20);
A substantially cylindrical coil case stopper (21) whose other end penetrates the flow rate measurement pipe (2) in a watertight manner. (e) Magnetic poles (A) and (B) are respectively arranged in the cone pipe (19) surrounding the pair of holes provided in the cone pipe (19). (f) Inside the coil case (20), an iron core (3) is provided, one end of which fits into the coil case end (20d).
), the coil (4) wound around this core (3), and the core (
3) A core end made of magnetic material that fits into the other end (3)
a), and the coil case end (20d) and core end (3a) are connected to the magnetic poles (B) and (A), respectively.
It is placed opposite to. (g) Cone heads (22) and (23) with bullet-shaped tips fitted on the upstream and downstream sides of the cone pipe (19)
. (h), a plane that includes the axes of the coil case (20) and the coil case stopper (21), and the flow rate measurement pipe (2);
Plate-shaped current plates (24) and (25) are provided on the upstream and downstream sides of the coil case (20) and the coil case stopper (21) in the fluid passage between the coil case (20) and the cone pipe (19).
). (i) The rectifier plates (24) and (25) are connected to the flow meter side pipe (2
) and the cone heads (22) and (23), respectively, and form part of the ground rib. (j) Coil case (20) and coil case stopper (
Electrodes (26) and (27) are provided on the flow rate measuring pipe in a direction perpendicular to the axis of the pipe 21) and the direction of fluid flow. 2. Part of the cylindrical part (20b) of the coil case (20)
2. A cone-type electromagnetic flowmeter according to claim 1, wherein is made of a magnetic material and is located between the core end (3a) and the magnetic pole A.