JP2941535B2 - Electromagnetic flow meter detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flowmeter detector having an explosion-proof structure which requires an explosion-proof structure and is suitable for, for example, a chemical plant.

[0002]

2. Description of the Related Art Electromagnetic flowmeter detectors having an explosion-proof structure (in order to satisfy the explosion-proof structure, the entire detector case has a pressure-resistant explosion-proof structure, and the electrode portion has an intrinsically safe explosion-proof structure). For example, various structures have been applied as a method of forming an electrode portion for extracting a signal line from a hermetic seal portion.

For example, as shown in FIG. 2, a base 5 and a housing 6 for forming a hermetic seal are welded to a pair of electrode holes 2 provided in a stainless steel measuring tube 1 by welding. And a structure in which the hermetic terminal 4 connected to the signal line from the electrode is fitted to the housing 6 and fixed using small screws, or as shown in FIG. And a structure in which an integrally formed outer casing 7 in which a fluid flow path 8 and an electrode chamber 9 corresponding to the above are integrally formed of ceramic or the like is used.

[0004] However, these methods have several disadvantages. For example, according to the former, since the base 5 and the housing 6 are fixed to the measuring pipe 1 by welding, the base 5 and the housing 6 are used for dimensional defects due to distortion due to welding heat, quality control problems due to uneven welding, etc., and airtight tests of welded portions. There was a problem such as an increase in work time involved. According to the latter, there are problems of high cost associated with integral molding of ceramics and the like, and problems of workability and dimensional accuracy after molding.

[0005]

SUMMARY OF THE INVENTION The present invention provides a novel structure which can solve various problems such as problems caused by welding in the prior art, poor workability, high cost, low workability and low dimensional accuracy. An object of the present invention is to realize an electromagnetic flowmeter detector having an explosion-proof structure adopted for the configuration of an electrode portion.

[0006]

The electromagnetic flow meter detector according to the present invention has a through hole for fitting a measuring tube whose center line is orthogonal to the axis at the center of the cylinder in the longitudinal direction. A housing having concentrically opened lead holes and opposing inner walls of the through holes and communicating with the lead holes via a step and having hermetic terminal fitting holes respectively opened at both ends of the cylindrical body is provided with an axis of the cylindrical body. A measuring tube fixed to the detector case perpendicular to the magnetic flux axis and the flow axis of the fluid and having a pair of electrodes on a tube wall on a straight line perpendicular to the tube axis at the center in the longitudinal direction is connected to the pair of electrodes by the lead of the housing. Into the through hole for fitting the measuring tube so as to face the hole, and fixed in position to the detector case, and led out from the pair of electrodes of the measuring tube through the lead holes of the housing, respectively. The signal lines are connected to the hermetic terminals fitted and fitted for fitting the hermetic terminals at both ends of the housing, and the connecting surface between the housing and the measuring tube and the hermetic terminals and the holes for fitting the hermetic terminals. Each of the joint surfaces is formed to have a size that satisfies the depth length and gap size of the gap defined by the standard of the flameproof structure.

[0007]

In the electromagnetic flowmeter detector according to the present invention, a measuring tube is fitted into a through hole for fitting a measuring tube of a single-piece housing, and a signal line from an electrode is led out through a lead hole of the housing. Simply connect to the hermetic terminals that fit into the hermetic terminal insertion holes at both ends of the housing,
The assembly of the electrode part is completed. Since the joint surfaces of the housing, the measuring tube, and the hermetic terminals are formed to a size that satisfies the required depth length and gap size for explosion protection, the joint surfaces of the components are welded as in the prior art. There is no need for airtightness. Further, the housing is made of stainless steel or the like, and has better workability and higher dimensional accuracy than an integrally molded part made of ceramic or the like. Also, costs are reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 shows a configuration of an electrode portion in an electromagnetic flowmeter detector according to one embodiment of the present invention. In FIG. 1, a housing 13 is made of, for example, stainless steel, and has a through hole 14 for fitting a measuring tube whose axis and center line are orthogonal to each other at the longitudinal center of the cylinder, and is concentric with the axis of the cylinder. Lead holes 15 opened on inner walls facing through holes 14
Further, there is a hermetic terminal fitting hole 16 which communicates with the lead hole 15 via a step and is opened at both ends of the cylindrical body. The housing 13 is fixed to a detector case (not shown) with the axis of the columnar body orthogonal to the magnetic flux axis of the exciting unit (not shown) and the flow axis of the fluid.

The measurement tube 11 has a pair of electrodes 12 on the tube wall on a straight line perpendicular to the tube axis at the center in the longitudinal direction.
The measuring tube 12 is fitted into the through hole 14 for fitting the measuring tube so as to face the lead hole 15 of the housing 13 and is fixed to a detector case (not shown). The signal lines (not shown) led out from the pair of electrodes 12 of the measuring tube 11 through the lead holes 15 of the housing 13 are respectively fitted into and attached to the hermetic terminal fitting holes 16 at both ends of the housing 13. Connected to the hermetic terminal 4.

The joint surface between the housing 13 and the measuring tube 11 (at the through hole 14 for fitting the measuring tube) and the joining surface between the hermetic terminal 4 and the hole 16 for fitting the same are both defined by the explosion-proof structure standard. The gap is formed in a size that satisfies the depth length and the gap size of the gap.

In the electromagnetic flow meter detector according to one embodiment of the present invention having the electrode portion configured as described above, the measurement pipe is inserted into the measurement pipe fitting through hole 14 of the housing 13 which is a single component.
11 is fitted in such a way that the pair of electrodes 12 face the lead hole 15 and fixed in the detector case, the signal line from the electrode 12 is led out through the lead hole 15, and the hermetic terminals at both ends of the housing 13 are provided. The assembly of the electrode portion is completed only by connecting to the hermetic terminal 4 fitted and attached to the fitting hole 16.
Therefore, the workability at the time of assembling the electrode part is greatly improved as compared with the related art. Since the joint surfaces of the housing 13, the measuring tube 11 and the hermetic terminals 4 are formed to have dimensions that satisfy the required depth length and gap size for explosion protection, the joint surfaces of the respective components are different from those of the prior art. It is not necessary to achieve airtightness by welding or the like. Also, the housing 13 is made of stainless steel or the like, has better workability than an integrally molded part of ceramic or the like, and does not require welding at the time of assembly, so that there is no dimensional change due to thermal strain. Can be raised. Furthermore, workability is improved,
Since the work efficiency is improved such that the airtight test of the welded portion is not required, the cost is also reduced.

[0013]

As described above in detail, according to the present invention, a cylindrical body has a through hole for fitting a measuring tube whose axis and center line are orthogonal to each other in the longitudinal center, and is concentric with the axis of the cylindrical body. A housing having a lead hole opened on the opposed inner wall of the through hole and a hole connected to the hole through a step, and having a hole for fitting a hermetic terminal opened at both ends of the cylindrical body, has an axis of the cylindrical body as a magnetic flux axis and a fluid. A measurement tube fixed to the detector case perpendicular to the flow axis and having a pair of electrodes on a tube wall on a straight line perpendicular to the tube axis at the center in the longitudinal direction faces the pair of electrodes directly to the lead hole of the housing. As described above, a signal line led out from the pair of electrodes of the measurement tube through the lead hole of the housing is fixed to the detector case by being fitted into the through hole for fitting the measurement tube. The housing has a structure connected to hermetic terminals fitted and attached to both ends of the housing, and the joint surface between the housing and the measuring tube and the joint surface between the hermetic terminal and the fitting hole are both flameproof and explosion-proof. By realizing an electromagnetic flowmeter detector characterized in that it is formed to a size that satisfies the determined gap depth and gap size, it is possible to insert a through hole for fitting a measurement tube in a housing that is a single part. Inserting the measuring tube, fixing the position to the detector case, leading the signal line from the electrode through the lead hole, and connecting to the hermetic terminals that are fitted and attached to both ends of the housing, the assembly of the electrode part can be completed. Complete.
Therefore, the workability at the time of assembling the electrode part is greatly improved as compared with the related art. And since each joint surface of the housing, the measuring tube and the hermetic terminal is formed to a size satisfying the depth length and gap size required for explosion protection,
There is no need to achieve airtightness by welding or the like at the joint surface of each component as in the prior art. In addition, the housing is made of stainless steel, etc., has better workability compared to integrally molded parts such as ceramics, and does not require welding at the time of assembly. Can be raised. Further, the work efficiency is improved, and the work efficiency is improved such that the airtight test of the welded portion is not required, so that the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an electrode portion of an explosion-proof structure in an electromagnetic flowmeter detector according to an embodiment of the present invention in a state before assembly.

FIG. 2 is a perspective view showing an example of a configuration of an electrode portion of an explosion-proof structure in a conventional electromagnetic flowmeter detector in a state before assembly.

FIG. 3 is a perspective view showing another example of a configuration of an electrode portion of an explosion-proof structure in a conventional electromagnetic flowmeter detector in a state before assembly.

[Explanation of symbols]

 4 ... Hermetic terminal 11 ... Measuring tube 12 ... Electrode 13 ... Housing 14 ... Through hole for fitting measuring tube 15 ... Hole for lead 16 ... Hole for fitting hermetic terminal

Claims (1)

(57) [Claims] An electromagnetic flowmeter detector having an explosion-proof structure has a through hole for fitting a measuring tube whose axis and center line are orthogonal to each other at the center in the longitudinal direction of the cylinder, and is concentric with the axis of the cylinder. A housing having a lead hole opened on the opposed inner wall of the through hole and a hermetic terminal fitting hole which communicates with the lead hole and is opened at both ends of the cylindrical body respectively has an axis of the cylindrical body for the magnetic flux axis and the fluid. A measurement tube fixed to the detector case perpendicular to the flow axis and having a pair of electrodes on a tube wall on a straight line perpendicular to the tube axis at the center in the longitudinal direction faces the pair of electrodes directly to the lead hole of the housing. As described above, is fixed to the detector case by being inserted into the through hole for inserting the measuring tube, and a signal derived from a pair of electrodes of the measuring tube through the lead holes of the housing respectively. A wire connected to a hermetic terminal fitted into the hermetic terminal fitting hole at each end of the housing; and a joining surface between the housing and the measuring tube and a joining surface between the hermetic terminal and the fitting hole. The electromagnetic flowmeter detector is characterized in that each of them is formed in a size satisfying a depth length and a gap size specified in the explosion-proof structure standard.