JP6193033B2 - Method for manufacturing fluid heating device - Google Patents

Description

The present invention relates to a method for manufacturing a fluid heating device , and more particularly to a method for manufacturing a fluid heating device using a sheathed heater.

  A fluid heating device using a sheathed heater is known as a heating means for heating a fluid such as water or antifreeze. For the sheathed heater, an elongated cylindrical cartridge type is widely used because of its compactness and convenience. The outer shell of the sheathed heater is made of stainless steel, and a heater wire or an insulating material is inserted into the outer shell. The sheathed heater is purchased as a finished product and inserted into the shell. Airtightness between the sheathed heater and the shell at the sheathed heater opening is maintained by sealing with an O-ring or packing. And a fluid is heated by flowing a fluid through the space between a sheathed heater and the shell which covers this.

  This type of fluid heating device, for example, when current is surplus in a heat / electricity supply system (cogeneration), can not sell electricity in reverse flow at present, so heat the water as hot water Used for storage. In addition, about the sheathed heater, it describes in the patent document 1, for example.

Japanese Patent Laid-Open No. 7-249477

  As described above, the airtightness between the sheathed heater and the shell is maintained by sealing with an O-ring or packing. However, when the sealing material is heated by the sheathed heater, the deterioration occurs, and the fluid in the shell is externally exposed. There are concerns about leaks.

  Then, an object of this invention is to provide the fluid heating apparatus which prevented the leakage of the fluid by deterioration of a sealing material.

The method for manufacturing a fluid heating device of the present invention includes a cylindrical shell having a fluid inlet, a fluid outlet, and a heater insertion port, a cylindrical heater outer shell having a bottom at the front end and an open rear end, The fluid outlet is formed by drawing the tip of the shell into a cylindrical shape, and the heater insertion port is formed by drawing the rear end of the shell into a cylinder, by punching from the outside, forming a convex portion on the inside in the vicinity of the fluid outlet of the shell, after forming the convex portion, the rear end of the heater outer shell protruding from the heater insertion opening, and A step of inserting the heater outer shell into the shell such that a tip of the heater outer shell is placed on the convex portion, an inner peripheral surface of the heater insertion port, and an outer periphery of the heater outer shell bonding the surface by brazing or welding And the tip of the step of bonding the tip outer peripheral surface of the convex portion and the heater shell by brazing or welding, and bonding the heater insertion port and the heater shell, and the heater shell and the convex portion And a step of forming a sheathed heater by inserting a heater wire from an opening at the rear end of the heater outer shell and covering the heater wire with an insulating material after joining the outer peripheral surfaces .

  According to the present invention, since the heater outer shell is inserted into the shell and brazed or welded to maintain airtightness, the heater wire is inserted into the heater outer shell to form a sheathed heater. It is possible to prevent fluid leakage due to deterioration of the liquid. Further, since a sealing material such as an O-ring is not used, there is an advantage that the structure of the fluid heating device is simplified and the cost can be reduced.

It is sectional drawing explaining the manufacturing method of the fluid heating apparatus in the 1st Embodiment of this invention. It is sectional drawing in the XX line of FIG.1 (d). It is sectional drawing of the fluid heating apparatus in the 2nd Embodiment of this invention.

  Hereinafter, the manufacturing method of the fluid heating apparatus in the 1st Embodiment of this invention is demonstrated based on drawing. FIG. 1 is a cross-sectional view illustrating a method for manufacturing a fluid heating device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line XX in FIG.

  As shown in FIG. 1A, a shell 10 having a fluid inlet 11, a fluid outlet 12, and a heater insertion port 13 is prepared. The shell has a cylindrical shape, and in this embodiment, has a cylindrical shape. The fluid inlet 11 is formed on the upper surface of the rear end of the shell 10. The heater insertion port 13 is formed by drawing the rear end of the shell 10 into a cylindrical shape. The fluid outlet 12 is formed by drawing the tip of the shell 10 into a cylindrical shape.

  Further, the lower portion of the tip of the shell 10 on the fluid outlet 12 side is punched from the outside, so that a convex portion 14 is formed inside the vicinity of the fluid outlet 12 of the shell 10. The convex part 14 becomes a base which joins the front-end | tip outer peripheral surface of the heater outer shell 20 so that it may mention later.

  Next, as shown in FIG. 1B, the heater outer shell 20 is inserted into the shell 10 from the heater insertion port 13. The heater outer shell 20 has a cylindrical body having a bottom at the front end and an open rear end, and has an elongated cylindrical shape in the present embodiment. The heater outer shell 20 is inserted so that the rear end 21 protrudes from the heater insertion port 13. Further, the tip 22 of the heater outer shell 20 is placed on the convex portion 14, so that the heater outer shell 20 can be stably held in the shell 10.

  Next, as shown in FIG.1 (c), the inner peripheral surface of the heater insertion port 13 and the outer peripheral surface of the heater outer shell 20 are joined by brazing or TIG welding in order to maintain airtightness. At this time, in order to enable brazing, the heater outer shell 20 and the shell 10 are preferably made of the same metal, for example, copper or stainless steel. When the heater outer shell 20 and the shell 10 are made of stainless steel, a paste-like brazing material based on nickel and added with silica is used. This brazing material is applied in the vicinity of the heater insertion port 13, and is permeated between the inner peripheral surface of the heater insertion port 13 and the outer peripheral surface of the heater outer shell 20, and then heated in an electric furnace to melt the brazing material. Perform brazing.

Further, an inflow pipe body 15A having an inflow port 15B is attached to the fluid inflow port 11 of the shell 10 by brazing or TIG welding. The inlet 15B of the inflow tube 15A communicates with the internal space of the shell 10 via the fluid inlet 11 of the shell 10. To the fluid outlet port 12 of the shell 10 to attach the outlet tube 16 A having an outlet 16B by brazing or TIG welding. The outflow port 16 </ b> B of the outflow tube body 16 </ b> A also communicates with the internal space of the shell 10 via the fluid outflow port 12 of the shell 10. The outer peripheral surface of the tip of the heater outer shell 20 can be joined to the convex portion 14 by brazing or TIG welding in order to be fixed to the convex portion 14.

  Next, as shown in FIG. 1D, a sheathed heater is formed by inserting a heater wire 23 from the opening of the rear end 21 of the heater outer shell 20 and covering the heater wire 23 with an insulating material 24. Since the heater wire 23 is an electric wire that generates heat when energized, such as a nichrome wire, and is folded near the bottom of the heater outer shell 20, two heater wires 23 are taken out from the rear end 21 of the heater outer shell 20. .

  The reason why the heater wire 23 and the insulating material 24 are inserted into the heater outer shell 20 after the outer shell 20 and the shell 10 are brazed or welded is that when the sheathed heater is already formed at the time of brazing or welding. This is because the heater wire 23 and the like may be deteriorated or damaged by heat during attachment or welding.

Then, when using the fluid heating apparatus of this embodiment energizes the heater wire 23, in a state of being exothermic, and flows the fluid into the shell 10 through the inlet 1 5 B of the inlet tube 1 5 A. The fluid that has flowed into the shell 10 flows in the space between the heater outer shell 20 and the shell 10 while being heated along the longitudinal direction of the shell 10 and flows out from the outlet 16B of the outlet pipe body 16A.

  As described above, according to the present embodiment, only the heater outer shell 20 is preceded and joined to the shell 10 by brazing or TIG welding, and integrally molded, whereby fluid leakage due to deterioration of a sealing material such as an O-ring. In addition, since a sealing material such as an O-ring is not used, the structure of the fluid heating device can be simplified and the cost can be reduced.

  Next, the manufacturing method of the fluid heating apparatus in the 2nd Embodiment of this invention is demonstrated based on FIG. This embodiment is different from the first embodiment in that a turbulent flow generating fin 25 is joined to the outer peripheral surface of the heater outer shell 20 by brazing or TIG welding. The fins 25 have a function of generating turbulent flow in the fluid flowing between the heater outer shell 20 and the shell 10 and promoting heat transfer from the sheathed heater to the fluid. The shape of the fin 25 can be selected from a spiral shape or a protrusion shape.

  When the fin 25 is brazed, the fin 25 is temporarily fastened to the outer peripheral surface of the heater outer shell 20, and a paste-like brazing material is applied to the tip of the drawing, not from the drawn heater insertion port 13. Insert from the tip of the previous shell 10. Similar to the first embodiment, the rear end 21 of the heater outer shell 20 protrudes from the heater insertion opening 13 to the outside. When welding the fins 25, the heater outer shell 20 to which the fins 25 are welded is inserted from the tip of the shell 10. Thereafter, the tip of the shell 10 is drawn. Thereafter, similar to the first embodiment, the process continues to the application of brazing material to the vicinity of the heater insertion port 13, brazing, and insertion of the heater wire 23 and the insulating material 24.

  According to this embodiment, since it is integral molding by brazing or welding, the fin 25 can be formed easily, and in addition to the effect of the first embodiment, a highly efficient heat transfer effect is added. Can do.

DESCRIPTION OF SYMBOLS 10 Shell 11 Fluid inflow port 12 Fluid outflow port 13 Heater insertion port 14 Convex part 15A Inflow pipe body 15B Inlet 16A Outflow pipe body 16B Outlet 20 Heater outer shell 21 Rear end 22 Front end 23 Heater wire 24 Insulating material 25 Fin

Claims (2)

Preparing a cylindrical shell having a fluid inlet, a fluid outlet and a heater insertion opening, and a cylindrical heater outer shell having a bottom at the front end and an open rear end;
The fluid outlet is formed by drawing the tip of the shell into a cylinder, and the heater insertion port is formed by drawing the rear end of the shell into a cylinder,
Punching the shell from the outside to form a protrusion on the inside of the shell near the fluid outlet;
After forming the convex portion, protruding rear end of the heater outer shell from the heater insertion opening, and such that the tip of the heater shell is placed on the convex portion, the said heater shell Inserting it into the shell;
Joining the inner peripheral surface of the heater insertion port and the outer peripheral surface of the heater outer shell by brazing or welding , and joining the convex portion and the outer peripheral surface of the tip of the heater outer shell by brazing or welding ; ,
After joining the heater insertion port and the heater outer shell and joining the convex portion and the outer peripheral surface of the front end of the heater outer shell, a heater wire is inserted from the opening at the rear end of the heater outer shell, and the heater And a step of forming a sheathed heater by covering the wire with an insulating material. The method for manufacturing a fluid heating apparatus according to claim 1 , further comprising a step of joining a turbulent flow generating fin to the outer peripheral surface of the heater outer shell by brazing or welding.

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