JP2017129512A - Structure and method for welding lead tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure and a method in which a lead tube as a tubule is joined between pressure containers at the shortest distance.SOLUTION: In a structure in which the lead tube is welded to the pressure container, there is provided a lead tube having a flange which is laser-welded to the tip, and a pressure container having a port in a penetration part, the flange including a tapered part and the port including an opening in a port hole. The tapered part of the flange is joined by spot resistance welding at an inner diameter edge part of the opening. A method for welding the lead tube is also provided.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a welding technique for joining a pressure vessel provided for pressure transmission through a pressure vessel holding a high-pressure fluid.

  For pressure vessels that hold high-pressure or high-temperature gas / liquid fluids, pressure signals are connected to the outside or outside by pressure guiding tubes, for example, mainly in reactor vessels in reactors, and small in gas chromatography and other measuring devices. A pressure guiding tube is installed for this purpose.

First, the invention disclosed in Patent Document 1 presents a method of joining a pressure guiding tube or the like to a nuclear reactor vessel, and points out the problems of conventional brazing joining. Brazing joints have problems such as poor strength and easy formation of bubbles. In this invention, the pressure vessel is provided with a through sleeve, and a pressure guiding tube is installed on the end surface of the pressure vessel via a socket, and the through sleeve and the socket are joined by welding to prevent leakage of fluid from the through portion. It was intended.

On the other hand, it is an object of the invention of Patent Document 2 to provide a fluid connection system that improves the performance of chromatography by ensuring a zero dead space and a leak-free seal. A fluid connection system is provided that includes a port having a capillary receptacle with an end sealing surface and a threaded wall. The fluid connection system includes an axial hole that allows a capillary tube having a front end face that abuts the end sealing surface of the port in a sealed state, and a mating screw wall corresponding to the thread wall of the port. And a mounting nut having. This sealing element is made of polyetheretherketone (PEEK).

JP 62-145200 A JP 2014-095700 A

In the invention of Patent Document 1, due to its large-scale structure, the protruding portions of the penetration sleeve and the socket are large from the wall surface of the pressure vessel. On the other hand, the invention of Patent Document 2 has a structure in which a capillary is attached to the through-port and a so-called zero dead space is realized by screwing with a mounting nut from the outside of the capillary. .

The main object of the present invention is a structure and method for joining a pressure guiding tube, which is a thin tube having an outer diameter of Φ1 mm and a wall thickness of 100 μm, at the shortest distance between pressure vessels. Therefore, in the differential pressure sensor system as shown in FIG. 1, the pressure guiding tube 10 is connected to obtain the differential pressure between the pressures of the fluid held in the pressure vessels 1 and 2. If the length of the pressure guiding tube is increased, a transmission delay occurs, and the pressure loss increases and the measurement accuracy decreases. Therefore, it is necessary to shorten the pressure guiding tube length as much as possible.

The present invention has a structure in which a pressure guiding tube is welded to a pressure vessel, and includes a pressure guiding tube having a flange laser-welded to a tip portion, and a pressure vessel having a port in a penetrating portion,
The flange includes a tapered portion, the port has an opening in a port hole, and the tapered portion of the flange is joined by spot resistance welding at an inner diameter corner of the opening. It is a welding structure of a pressure guiding tube.

Further, the present invention relates to a method for welding a pressure guiding tube to a pressure vessel,
A step of providing a flange having a tapered portion, a pressure guiding tube, and a pressure vessel having a through-port, a step of attaching the flange to a tip portion of the pressure guiding tube, and laser welding the tip portion groove; A pressure guiding tube welding method comprising: pressing a pressure guiding tube having the flange against a through-port; and resistance welding the pressure guiding tube to the pressure vessel at a predetermined spot of the port hole.

  According to the present invention, the pressure guiding tube can be joined to the pressure vessel only by simple two-stage welding. Since the flange is inserted into the through-port of the pressure vessel and welded, the extra protruding height (dH in FIG. 1 example) outside the pressure guiding tube can be shortened as much as possible, and the pressure guiding tube length can be shortened as much as possible.

Overall configuration diagram of differential pressure sensor according to an embodiment of the present invention Detailed view of pressure guide tube and flange mounting according to an embodiment of the present invention Detailed view of through-port of pressure vessel according to an embodiment of the present invention The welding situation figure of the pressure guide pipe to the penetration port of the pressure vessel concerning the embodiment of the invention of this application The flowchart of the welding method which is an Example of this invention

(1) Application Example of the Invention of the Present Application FIG. 1 shows a configuration diagram of a differential pressure sensor. The pressure vessels 1 and 2 receive high and low pressures with a diaphragm or the like, and a differential pressure is measured by a predetermined sensor inside the pressure vessel, so that a pressure guiding pipe 10 that connects the pressure vessels is connected by piping. . Since the present invention is related to the welding of the pressure guiding tube to the pressure vessel, description of pressure measurement is omitted.

  Since the external protrusion height dH viewed from the through-port 110 of the pressure vessel 1 or 2 (which is a port provided as a through-portion, hereinafter referred to as “through-port”) needs to be as short as possible, The flange 100 to be connected is directly joined to the through port 110.

In the subsequent drawings, a main part of the present invention will be described based on a cross-sectional view viewed from the left side of FIG. 1 (in the direction of arrow A in the figure).

(2) Embodiment of the Invention of the Present Application FIG. 2 shows a state of mounting the pressure guiding tube 10 and the flange 100 according to the embodiment of the present invention. The upper diagram is a bird's-eye view of a three-dimensional shape, and a conical flange 100 is passed through the tip of the pressure guiding tube 10.
The member appearing in this article is a metal, which is equivalent to stainless steel (SUS304).

  The flange 100 is provided with a cylindrical groove 101 at the tip, and subsequently with a tapered portion 102. Furthermore, there is a washer-shaped washer portion 103. These are processed with an integral metal.

  Then, the washer 100 passed through an appropriate position of the pressure guiding tube 10 is joined to the pressure guiding tube 10 by the groove 101 by laser welding. A laser beam is irradiated as indicated by a dotted line 108 in the figure. This will perform all-around laser welding. Note that the degree of bonding is good when the angle of the laser beam 108 is about 20 ° from the vertical direction of the pressure guiding tube.

  The lower part of FIG. 2 shows a sectional view thereof. The taper angle Θ of the taper portion 102 of the flange 100 is marked. The taper is applied at approximately 30 to 60 degrees.

  Next, FIG. 3 shows a cross-sectional shape of the through-port 110 of the pressure vessel 1 (the same applies to 2). The through port serves as an inlet or outlet for fluid to the pressure vessel by the pressure guiding tube.

As can be seen from FIG. 3, first, a slightly larger hole is cut in the wall of the pressure vessel 1 to a predetermined depth. Next, a small port hole 111 is dug to penetrate the pressure vessel 1. As a result, burrs remain on the outside of the port hole 111, which is chamfered with a reamer or the like. The result is a chamfered portion 112 (shown somewhat exaggerated in the figure). This can be done all around the outer corner of the port hole 111.

The opening angle Γ of the chamfered portion 112 is shown. This opening angle has a predetermined condition.
Opening angle Γ> Flange taper angle Θ (1)
As represented by the formula (1), it is essential that the opening angle of the chamfered portion is wider than the taper angle of the flange 100. In this case, a part of the taper 102 of the flange 100 comes into contact with the welding spot 114 that is the inner diameter corner (top) of the port hole 111.

  The welding situation will be described with reference to FIG. The pressure guiding tube 10 having the flange 100 joined thereto is inserted into the through-port 110 of the pressure vessel 1 described above. The taper 102 of the flange 100 contacts the object to be welded at a welding spot 114. Since the taper of this example is circular, the welding spot contacts at the circumference indicated by 114.

Here, the washer portion 103 of the flange 100 is pressed from the outside (arrow on the right side of the figure).
Specifically, the electrode 22 a wired from the resistance welder 20 and the transformer 21 is pressed from the outside of the washer portion 103. The other electrode 22 b is connected to the other end of the pressure vessel 1.

  When a large current is applied from the resistance welding machine 20, the entire circumference nugget is generated at the welding spot 114 applied to the port hole 111 of the through-port 110 and the tapered portion 102 of the flange 100, and the welding is performed directly. As the welding conditions, it is sufficient to apply an instantaneous voltage of about several tens of mSec with a voltage of 2.5 V, a current of 2 kA, and a pressure of 16 kGf.

(3) Embodiment of Method Invention The present welding flow will be described with reference to FIG. First, work starts from Step 0.

<Step 1> A pressure vessel 1 provided with a flange 100, a pressure guiding tube 10, and a through-port 110, which are pre-processed metal members, are prepared.

<Step 2> Through the flange 100 through the pressure guiding tube 10, the flange 100 is joined to the pressure guiding tube 10 by laser welding at a predetermined position as appropriate at the groove 101.

<Step 3> The pressure guiding tube 10 with the flange 100 is inserted into the through port 110 of the pressure vessel 1 and pressed.

<Step 4> The pressure guide tube 10 is directly resistance-welded to the pressure vessel 1. The welding spot is joined on the entire circumference of the welding spot 114 as described above.

<Step 5> The welding result is confirmed, and if there is no problem, the welding of the pressure guiding tube is completed (to Step 6). If there is a deficiency in the joining state, control processing for adjusting the resistance welding machine 20 or the like is performed (Step 10), the process loops to Step 1, and the process is repeated.

  In the above example, the tapered portion 102 of the flange 100 has been described as having a conical shape, but is not limited to such a linear taper, and may be a parabolic shape or a spherical shape. The taper angle may be obtained from the tangential slope. Since the tapered portion 102 of the flange 100 is subjected to resistance welding at one point (one round) of the welding spot 114 at the inner diameter corner portion of the port hole 111 and can be pressure-sealed, for example, than the port hole 111 at the outer diameter corner portion. There is less bias in the internal pressure.

  The invention of the present application is an invention useful for manufacturing a device that uses a pressure guiding tube for all sensors other than a differential pressure sensor.

DESCRIPTION OF SYMBOLS 1, 2 Pressure vessel 10 Impulse pipe 20 Resistance welding machine 21 Transformer 22a, b Electrode 100 Flange 101 Groove 102 Tapered part 103 Washer part 108 Laser beam 110 Through-port 111 Port hole 112 Chamfer part 114 Welding spot

Claims (2)

In the structure where the pressure guiding tube is welded to the pressure vessel,
The pressure guiding tube having a flange laser-welded to the tip;
Using the pressure vessel provided with a port in the penetrating portion,
The flange includes a tapered portion,
An opening structure is provided in the port hole in the port hole, and the tapered portion of the flange is joined by spot resistance welding at an inner diameter corner portion of the opening portion. In a method of welding a pressure guiding tube to a pressure vessel,
Providing a flange having a tapered portion, a pressure guiding tube, and a pressure vessel having a port in the penetrating portion;
Attaching the flange to the tip of the pressure guiding tube and laser welding the groove at the tip;
Pressing the pressure guiding tube having the flange against the port of the penetrating portion provided in the pressure vessel;
Resistance welding the pressure guide tube to the pressure vessel at a predetermined spot of the port hole;
A pressure guide welding method comprising:

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