JPH0465306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hot water boiler used in domestic water heaters and heating equipment.

2. Description of the Related Art A conventional hot water boiler of this type has a can body with a water chamber formed between an inner and an outer body, and is configured to heat the inner surface of the inner body of the can body with a heating element.

Problems to be Solved by the Invention However, in such a structure, one end and the other end are respectively closed and fixed between the inner and outer can bodies.
When the inner surface of the inner shell is heated by the heating element,
There was a problem with the glass lining on the inner and outer shell surfaces facing the water chamber peeling off.

In other words, due to the difference in the amount of heating between the inner and outer shells, stress is applied and peeling occurs. When this peeling occurs, corrosion occurs from that part, and eventually In some cases, holes were formed.

Therefore, an object of the present invention is to prevent the glass lining from peeling off.

Means for Solving the Problems And in order to achieve the above objects, the present invention provides the following:
Of the inner and outer shells, at least the inner shell has a bulge (also called bellows) process to prevent the glass lining from cracking.

Function: By doing this, the inner shell will expand well when heated, but the bulge-processed portion will work to minimize this expansion. By providing this bulge processing, the amount by which the inner shell expands can be reduced compared to a structure without the bulge processing. If this is done, stress will be less likely to work, and the glass lining will not come off. This therefore eliminates perforations.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings. In FIGS. 1 and 2, 1 is a can body in which a cylindrical water chamber 4 is formed between a cylindrical inner shell 2 and a cylindrical outer shell 3. A bulge process 7 is performed in which troughs 5 and peaks 6 are alternately and continuously formed above approximately the middle part. Note that the 7 portions of the bulge are formed by extruding the troughs 5 outward from the 2 surfaces of the inner shell, and the peaks 6 are flush with the 2 surfaces of the inner shell. Furthermore, the inner surfaces of the inner shell 2 and outer shell 3 facing the water chamber 4 are treated with glass lining 8. In addition, in the bulge-processed portion 7 of the inner shell 2, the material is deposited on the outer surface of the valley portion 5 by ejecting the material from the upper and lower ejection bodies toward the upper and lower peak portions 6. Further, the expanded pipe portion 9 at one end of the inner shell 2 and the outer shell 3, and the contracted pipe portion 10 at the other end of the inner shell 2 and the outer shell 3 are each closed and fixed by welding. 11
is a water supply port provided on the circumferential side wall of the outer shell 3 so as to face the trough 5 of the bulge 7 of the inner shell 2.

12 is a hot water supply port on the upper part of the outer shell 3. Reference numeral 13 denotes a hot water temperature detector, which is provided on the circumferential side wall of the outer shell 3 so as to face the peak 6 of the bulge 7 of the inner shell 2. Reference numeral 14 designates a plurality of buff-full plates provided on the peripheral wall of the prismatic body, which are provided so as to face the valley portions 5 of the bulge processing 7 of the inner shell 2. Reference numeral 15 denotes a cylindrical combustion cylinder of a swirling burner used as an example of a heating element, and a large number of swirling air injection holes 16 are provided around the side wall of the cylindrical combustion tube.
is provided in the tangential direction and communicates with a blower composed of a motor 17, a fan 18, and a fan case 19. 20 is a nozzle as a fuel atomization means, and an electromagnetic pump 21 is connected to the oil tank (not shown).
Fuel is sprayed from the tip through. Reference numeral 22 denotes a cylindrical auxiliary combustion cylinder with openings 23 provided around the combustion cylinder 15 to prevent oil particles ejected from the nozzle 20 from colliding with each other, and forms a mixing chamber 24 between the combustion cylinder 15 and the combustion cylinder 15 .

Reference numeral 25 denotes a ring-shaped burner ring for forming a combustion chamber 26 in the lower part of the inner shell 2.

In the above configuration, the combustion air and fuel particles are
Mixing and vaporization are promoted in the mixing chamber 24, and swirling vaporization combustion is performed in the upper part of the combustion tube 15, and while the combustion gas passes between the buff-full plate 14 and the inner shell 2, it is mixed with water in the water chamber 4. When the two surfaces of the inner shell are heated by the combustion heat of the burner, the maximum elongation due to thermal expansion of the inner shell 2 and outer shell 3 is theoretically calculated as a( Linear expansion coefficient of material 1/℃)
×T (℃) (average temperature) × L (length mm), but the average temperature of the outer shell 3 is due to indirect heating.
While the temperature of the hot water is approximately the same, the average temperature of the inner shell 2 is high due to the heat of combustion, and the amount of elongation of the inner shell 2 due to thermal expansion is greater than the amount of elongation of the outer shell 3. At this time, since the inner shell 2 and the outer shell 3 are closed and fixed at both ends, compressive stress is applied to the inner shell 2 and tensile stress is applied to the outer shell 3.However, according to the present invention, In one embodiment, the bulge processing 7 is applied to the two surfaces of the inner shell, so although the two surfaces of the inner shell become high in temperature, the bulge processing 7 has the function of absorbing thermal expansion, and the inner shell The amount of elongation of the outer shell 3 can be made almost the same as the amount of elongation of the outer shell 3.

Data obtained through experiments regarding the above characteristics will be explained with reference to FIGS. 3 and 4. FIG. 3 shows an example of the expansion characteristics of the can body 1 having a two-inner shell configuration without the bulge process 7, and FIG. show. In the figure, the expansion lengths of the inner shell 2 and outer shell 3 are the inner, outer shell 2,
The amount of elongation was measured in a free state without closing or fixing one end of 3. For one can unit, the elongation was measured with both ends of the inner and outer shells 2 and 3 closed and fixed. This shows what was measured.

That is, the expansion length of the structure without the bulge processing 7 in FIG. 3 is the theoretically calculated value, (a・
T・L), but the expansion length with bulge 7 in Figure 4 is (a・T・(L−l)), which proves that bulge 7 absorbs the expansion. This eliminates compressive stress and tensile stress acting on the inner and outer shells 2 and 3, and eliminates peeling of the glass lining 8.

Although the expansion absorption effect of the bulge process 7 has not been fully analyzed at present, according to our analysis, as shown in Figure 5, the expansion absorption effect of the bulge process 7 and the Due to the full plate 14, there is a difference in warm/cold temperature distribution between the valleys 5 and peaks 6 that receive the flow of combustion gas, and furthermore, there is a similar temperature distribution in the water chamber 4 of the bulge processing section 7. There is a difference, which is thought to be due to deformation in the stress distribution in the 7-part bulge process. Moreover, the same thing can be said not only for the swirl burner in this embodiment but also for a pot-type burner in which the exhaust gas rises uniformly.

A second embodiment of the present invention will be described below with reference to FIG. Components that are the same as those in FIG. 1 are given the same numbers, and detailed explanation thereof will be omitted. Therefore, in FIG. 6, only the changes from FIG. 1 will be explained.

In this example, the form of the burner used as the heating body is changed. That is, the burner shown in FIG. 1 is a swirl type burner, whereby the combustion gas rises uniformly over the entire circumference of the inner shell 2. In contrast, the one in Figure 6 has inner shell 2 and outer shell 3 of can body 1.
This is a gun-type burner that is inserted through the side of the cylinder and burns it. With this gun type burner, combustion is a diffused yellow flame, so the flame temperature is higher than that of the vaporized blue flame combustion shown in Figure 1, and the combustion flame concentrates and collides with the part of the inner shell 2 facing the burner. As a result, the temperature rises and the combustion gas flows unevenly to the inner surface of the inner shell 2. However, in this embodiment, the firebox wall 27 prevents flames from colliding with the inner shell 2, and the burner ring 25 prevents the flames from colliding with the inner shell 2. The temperature distribution of the exhaust gas within the combustion chamber 26 is made uniform, and the number of ridges of the bulge processing 7 is increased to reduce the amount of expansion, thereby achieving the same effect as in the previous embodiment. be.

FIG. 7 shows a third embodiment.

Compared to the one shown in FIG. 1, the lower ends of the inner shell 2 and outer shell 3 are straight without spinning, and a ring-shaped bottom plate 28 is fitted and welded to both ends.
That is, in this embodiment, only the upper side is welded first, the glass lining base material is poured into it, and then the ring-shaped bottom plate 28 is joined by welding to form the integral hollow can body 1. Even in this method, the glass lining 8 can be applied uniformly, and the can body 1 can be stored in a joined state rather than separately for the inner and outer shells, so that the installation space can be reduced.

Other features of this embodiment are listed below.

(1) The water supply port 11 is provided on the circumferential side wall of the outer shell 3 so as to face the trough 5 of the bulge 7 of the inner shell 2, so that the speed of the supplied water is reduced as it hits the trough 5. After being decelerated, the speed is further decelerated as it moves toward the peaks 6 above and below the troughs 5. Therefore, even if the water is supplied quickly, the speed of the water flowing upward is reduced, and less water goes directly to the hot water supply port 12, so that a high and stable hot water temperature can be obtained. Moreover, since the water is guided more quickly in the circumferential direction along the mountain portion 6, the water can be heated more efficiently.

(2) The hot water temperature detector 13 is provided on the circumferential side wall of the outer shell 3 facing the peak 6 of the bulge 7 of the inner shell 2, so that the water temperature of the hot water temperature detector 13 is Since the water is guided in the circumferential direction along the portion 6, the water temperature is uniformly heated, and good water temperature detection without local boiling can be performed.

(3) By providing the full plate 14 opposite to the trough 5 of the bulge 7 of the inner shell 2, the gap between the trough 5 and the peak 6 of the bulge 7 can be filled without reducing the ventilation function. , can be set small, and can generate turbulence in the flow of combustion gas to promote heat exchange, resulting in highly efficient characteristics.

Effects of the Invention As described above, according to the present invention, at least the inner shell surface of the inner shell and the outer shell, which receives a large heat load due to the heating body, is provided with a heat absorbing material that is applied to the upper half of the total length of the inner shell in accordance with the temperature rise received by the inner shell and the outer shell. In order to prevent thermal stress from being partially concentrated in the range of 1 and 2, it is possible to apply a bulge process to the glass by continuously forming R curves of the same shape without straight parts so that the heat stress can be evenly distributed and absorbed at the peaks and valleys. This is an important point that can completely prevent lining cracking, and our experimental data shows that if the ridges and valleys have different R dimensions, or if the R part is straight but has a sharp bend. In this case, it is not possible to absorb thermal stress evenly and dispersedly, and the thermal stress is partially concentrated at the steepest R part, and even though it is the same expansion tube, the stress is concentrated and the glass lining in that area is affected. This results in cracking. In the present invention, the elongation within the entire length of the bulge processing part can be dispersed and absorbed by all the peaks and troughs, and the elongation of the entire length of the inner shell can be set to be exactly the same as the elongation of the outer shell. We provide a can body with bulge processing that is ideal for preventing cracking of the glass lining, by relaxing the stress in the equalizing parts at both ends and preventing stress from concentrating on the tube contraction part of the outer shell, the tube expansion part of the inner shell, and the bulge processing part. It is something to do.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of one embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line A-A' in Figure 1, Figure 3 is a diagram showing the expansion characteristics of the can without bulging, and Figure 4 is the can with bulging according to an embodiment of the present invention. FIG. 5 is a diagram showing the expansion and absorption characteristics of the bulge-processed portion of the present invention, and FIGS. 6 and 7 are front sectional views of other embodiments. 1...Can body, 2...Inner shell, 3...Outer shell, 4...
Water chamber, 7...Bulge processing, 8...Glass lining.

Claims (1)

[Claims] 1 A can body with a water chamber formed between the inner shell and the outer shell by welding the expanded pipe part of one end of the inner shell and the outer shell, and the contracted pipe part of the other end of the inner shell and the outer shell, and this can body. a heating element for heating the inside of the inner shell, a glass lining is provided on the inner and outer shell faces of the can body facing the water chamber;
In the circumferential direction of at least the upper half of the inner shell of the outer shell, there are valleys extruded outward from the inner shell surface and peaks flush with the inner shell surface, which are curved in the same shape without straight parts. A hot water boiler that is formed alternately and continuously, and has a bulge process to prevent the glass lining from cracking due to thermal distortion from the heating element.