JPH0324423A - Electrode structure of detector in electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To prevent noises, to make the structure of an electrode part compact and to make the entire detector compact by expanding the side surface of an electrode body part outward by the compressive insertion of an electrode shaft so that the side surface is brought into contact with the inner wall surface of an electrode attaching hole. CONSTITUTION:An electrode 3 is composed of a cylindrical electrode body part 4 having a bottom and an electrode shaft part 5. One end of the shaft part 5 is formed in a spherical shape having the outer diameter which is slightly larger than the inner diameter of the body part 4. The other end of the shaft part 5 is formed as a circular flange having the outer diameter which is approximately equal to the body part 4. The length from the inner surface of the flange to the tip of the spherical part is approximately equal to the depth of the central hole of the body part 4. The body part 4 is inserted into an electrode attaching hole 2 of a measuring pipe 1 from the outside of the measuring pipe so that the end surface of the bottom of the body part 4 faces the inner surface of the measuring pipe 1. The shaft part 5 is compressed into the body part 4 until the spherical tip comes to contact with the bottom of the central hole of the body part 4. Sealing is achieved between the side surface of the body part 4 and the attaching hole 2. Thus, the gap between the side surfaces of the attaching hole 2 and the body part 4 becomes small, and the depth of the gap also becomes small. Therefore, the possblity of stagnation of air and the like in the gap becomes less.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to the structure of an electrode section of an electromagnetic flowmeter detection unit.

(Prior technology) There are two types of electrodes for electromagnetic flowmeter detectors: one is an internal volatile type in which the electrode is inserted into a mounting hole from inside the measuring tube of the detector and fixed with a nut, and the other is an internal volatile type in which the electrode is inserted from the outside of the measuring tube. There is a ``gashin form'' with a structure to be inserted.

In the case of the internal displacement type, it is necessary to insert the electrode from the inside, so the diameter of the detector, that is, the inner diameter of the measuring tube, must be larger than the length of the electrode. It was difficult to do so.

In addition, in the case of the outer god type, as shown in Fig. 4, the fluid in the lining (32) of the 41-ri constant tube (31) is
) is sealed at the O-ring (35) attached to R (34), and the part that seals the fluid is located far deeper than the inner surface of the measuring tube, so the wetted end of the electrode (33) There may be a long and narrow gap on the side surface of the electrode between the electrode and the seal, and if air or the like accumulates in this area, there is a risk that it will cause noise.

The ratio of these electrode portions to the diameter of the detector increases as the diameter decreases, which has been a factor that prevents miniaturization of the detection device.

(Problems to be Solved by the Invention) The present invention is of an external capture type in order to be applicable to small-diameter detectors, and seals with the mounting hole on the side of the electrode near the inner surface of the measuring tube. It is an object of the present invention to realize an electrode structure for an electromagnetic flow meter detector in which the structure of the electrode part is compact, and this is also an object of the present invention.

[Structure of the invention]

(Means for Solving the Problems) The electrode structure of the electromagnetic flowmeter detector of the present invention includes a cylindrical electrode body with a bottom and a spherical shape with an outer diameter slightly larger than the inner diameter of the electrode body. One end is formed into a circular flange having an outer diameter approximately equal to that of the electrode body, and the length from the inner surface of this flange to the spherical tip is approximately equal to the depth of the center hole of the electrode body. The electrode body part is inserted into the electrode mounting hole of the measurement tube from the outside of the measurement tube so that its bottomed end surface faces the inner surface of the measurement tube, and the electrode body part is inserted into the electrode shaft part. The shaft part is press-fitted until its spherical tip contacts the bottom of the center hole of the body part, and the structure is such that it is sealed between the measuring surface of the electrode body part and the electrode mounting hole.

(Production m) In the electrode structure of the electromagnetic flowmeter detector of the present invention, the bottom outer surface of the electrode body comes into contact with the fluid to be measured. The spherical tip of the press-fitted electrode shaft portion causes the side wall surface of the electrode body portion to expand outward and come into contact with the inner wall surface of the electrode mounting hole of the illll fixed tube to effect a seal. As a result, the gap between the electrode mounting hole and the side surface of the electrode body portion is small, and the depth of the gap from the bottom outer surface of the electrode body portion is also small, so the possibility that air or the like will accumulate in the gap is extremely reduced.

(Example) The present invention will be described in detail below based on the example shown in the drawings.

FIG. 1 and FIG. 2 show the electrode structure of an electromagnetic flowmeter detector according to an embodiment of the present invention. Measuring tube (1
) is provided with an electrode mounting hole (2) having a small-diameter stepped portion on the inner surface of the tube in a direction perpendicular to the tube axis direction.

The electrode (3) attached to this electrode attachment hole (2) is
As shown in FIG. 2, it is composed of a 1t pole body part (4) and an electrode shaft 1 part (5). Both are made of conductive material, such as stainless steel.

The electrode body part (4) has a cylindrical shape with a bottom, and a small diameter step part (6) is formed on the outer surface of the eave part, and a center hole (
A portion of a certain length from the open end 11 of 7) is formed into a large-diameter stepped portion (8) with a large diameter. Furthermore, the electrode body part (4
), three V-grooves (9a), (9b), and (9c) are formed around the entire circumference in areas corresponding to the center hole (7), and these V-grooves (9a), ( 9b), (9c)
An O-ring (11) is attached to each. The electrode mounting hole (2) of the measuring tube (1) is connected to the electrode body part (4).
) is machined with precision to ensure a mating relationship.

As shown in FIG. 2, the electrode shaft part (5) has one end shaped into a spherical shape with an outer diameter slightly larger than the inner diameter of the center hole (7) of the electrode body part (4), and the other end shaped like a sphere. is shaped into a circular flange having an outer diameter approximately equal to that of the electrode body portion (4);
The length from the inner surface of this flange to the spherical tip is approximately equal to the depth of the center hole (7) from the open end of the electrode body (4). Furthermore, the electrode shaft part (
A female threaded hole (10) for fixing an electrode lead wire is provided on the flange side end surface of 5).

The electrode (3) is attached to the measuring tube (1) as follows. That is, the electrode body part (4) is fitted into the electrode mounting hole (2) of the measuring tube (1) from the outside of the measuring tube, and the small diameter step part (6) on the bottom outer surface of the electrode body part (4) is inserted. 1! Insert it until it fits into the small diameter stepped part of the horizontal mounting hole (4) and stops. Next, fit the electrode shaft part (5) into the large diameter step part (8) from the open end of the electrode body part (4), and insert it into the center hole (7) until the spherical tip reaches the bottom of the center hole (7). Press fit. As a result, since the outer diameter of the spherical tips of the electrode shafts 1 to (5) is slightly larger than the inner fM of the center hole (7), the side wall surface with the V-groove of the electrode body part (4) is The O-rings (11) attached to VifH9a), (9b), and (9c) are connected to the electrode mounting holes (2).
Contact the wall and seal. After that, lead wire (l3)
The terminal lug terminal (l2) is connected to the electrode (3) by tightening the lug terminal fixing screw (l4) fitted into the female threaded hole (10).

In the electrode structure of the electromagnetic flowmeter sensing element of the embodiment of the present invention in structure 1 above, the structure is such that the side surface of the electrode body part (4) seals with the inner wall surface of the electrode mounting hole (2). , the structure of the electrode part becomes compact, and the entire detector can be made smaller. In addition, the electrode (3) is a Jll fixed tube (1
) Since it can be inserted and assembled from the outside of the measuring tube (1), the work is easy even though it is limited by the diameter of the measuring tube (1). Furthermore, since the sides of the electrode body (4) are structured to expand outward, the gap between the electrode body (4) and the electrode mounting hole (2) is reduced compared to conventional external shape electrodes. 4) The depth of the gap from the outer surface of the bottom is also small, so the possibility of air, etc. accumulating in the gap is extremely small. Next, another embodiment of the present invention is shown in FIG. This example is
When the measuring tube (21) is made of non-magnetic metal such as stainless steel, the inner surface of the measuring tube (2l) is lined with an insulating lining (22), and the electrode mounting hole (23) is also inside the measuring tube. A surface lining (22) extends part way into the hole. In this case, the electrode body part (4A) is not provided with a V-groove on its outer surface, and the outer periphery of the electrode body part (4A) is covered with a certain cover (24 ).

Then, a ■ groove (25) is formed on the outer surface of this cover (24), and a circle ring is attached to this V groove (25). The electrode body part (4^) with this cover (24) is attached to the measurement tube (2).
The electrode (3A) is fitted by fitting it into the electrode mounting hole (23) in step 1), and the electrode shaft portion (5) is press-fitted to complete the mounting and assembly of the electrode (3A). In this case as well, effects similar to those of the embodiments shown in FIGS. 1 and 2 can be obtained.

〔Effect of the invention〕

As detailed above, according to the present invention, the electrode is composed of a bottomed cylindrical electrode body and an electrode shaft having a spherical tip having an outer diameter slightly larger than the inner diameter of the electrode body. The electromagnetic flowmeter detector is assembled by fitting the electrode body into the electrode mounting hole of the measurement tube from the outside of the measurement tube, and then press-fitting the electrode shaft into the center hole of the electrode body. By realizing the electrode structure, m
By press-fitting the tb shaft portion, the side surface of the electrode body portion expands outward and comes into contact with the inner wall surface of the electrode mounting hole to perform sealing. As a result, the gap between the electrode mounting hole and the side surface of the electrode body is small, and the depth of the gap from the bottom outer surface of the electrode body is also small, so the possibility of air, etc. accumulating in the gap is extremely small, resulting in noise. is prevented. In addition, the structure of the electrode section becomes compact, making it possible to downsize the entire detector. Furthermore, since the electrode can volatilize and ML stand from the outside of the fixed tube, detectionff;: (Hl!
I set' [? ) can be carried out without being restricted by the diameter of the tube, and the work is easy.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the electrode structure of an electromagnetic flowmeter detector according to an embodiment of the present invention, Fig. 2 is a cross-sectional view showing an enlarged electrode of Fig. 1, and Fig. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view showing the electrode structure of the electrode flowmeter detector of the example, and the fourth is a cross-sectional view showing a conventional example of the outer-shaped electrode structure.

Claims (1)

[Claims] The electrode includes a cylindrical electrode body with a bottom and an electrode shaft having a spherical tip with an outer diameter slightly larger than the inner diameter of the electrode body. The electrode body part is inserted from the outside with the bottom end face facing the inside of the tube, and the electrode shaft part is press-fitted to seal between the side surface of the electrode body part and the inner surface of the electrode mounting hole. Electrode structure of electromagnetic flowmeter detector.