EP0719992B1

EP0719992B1 - Water heater

Info

Publication number: EP0719992B1
Application number: EP95600012A
Authority: EP
Inventors: Pantelis Charalampidis
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-12-22
Filing date: 1995-12-21
Publication date: 2001-10-10
Anticipated expiration: 2015-12-21
Also published as: EP0719992A2; GR2001648Y; EP0719992A3; DE69523131D1; ATE206814T1

Abstract

A support mechanism of the electric resistance in the heater/boiler which consists of the cap (2), FIG. 4.,the tubular bolt (7), which is fastened at the center of the cap (2) around the opening (3) in such away that it nestles outside the cord (or rim) (X). The rubber flange (10) is placed on the cord (X), the metal flange (4) with the electric resistance (5) and the magnesium rod (6) on the rubber flange. Then the externally threaded tubular nut is manually screwed into the internally threaded bolt until the lower surface of the of the tubular nut touches the metal surface of the electric resistance (4). In turn, a metal rod is inserted into the opening and the tubular nut is turned until it tightens completely the metal flange (4) of the electric resistance with the rubber flange (10). In ths way we have secured the electric resistance and at the same time we have hermetically closed the opening (3) of the cap (2) of the heater/boiler (1).

Description

This invention is about the bottom cap of a heater or boiler and is particularly related to water heaters/boilers of the high pressure closed circuit type and support mechanisms thereof. Normally, caps in water heaters/boilers in this category have a central opening, through which the inner cylindrical surface of the heater/boiler is enameled (vitrified) and the electric resistance along with the water heating mechanism is placed.
Caps with such mechanisms are known. They have a metallic neck , the outer end of which turns into a flange bearing eight holes. The other end is soldered circumferentially at the center of the cap. The flange with the electric resistance is mounted onto the cap with a rubber flange in between and with the aid of eight bolts and nuts the resistance is fastened and the opening of the cap is thereby closed.
The use of such a mechanism, in which the nuts are tightened to support the resistance and make it waterproof, tends to deform the metal surfaces of the mechanism. This in turn results to the cracking of the enamel of the inner surface of the heating apparatus, thereby creating oxidation and water leakage from the heater or boiler and eventually renders the whole apparatus useless.
Caps fitted with mechanisms different from the one above are those fitted with a clamp. The opening at the center of such a cap is oval in shape with a circumferential groove, whereupon the rubber flange of the electric resistance bearing a fixed bolt and nut is seated.
When the outer oval shaped metal flange, as well as that of the resistance are tightened by the fixed bolt and nut, the metal flange is forced to press the rubber flange of the cap into the groove together with the electric resistance against the inner wall of the opening.
The purpose of the oval shaped opening in this case is to facilitate the insertion of the metal flange of the electric resistance into the boiler to tighten from the inside outwards. When using this type of mechanism, the groove available for the positioning of the rubber flange causes problems to the enamel of the inner surface of the boiler, around and within the groove, resulting to lack of homogeneity in the mass of the enamel.
This lack of homogeneity, i.e. non uniform thickness of the enamel causes its cracking when the clamp is tightened. In turn oxidation follows because of this problem, i.e. with this type of tightening of the electric resistance (clamp). Thus the whole heating apparatus soon becomes useless. Moreover, the temperature and the pressure of the water tend to push the rubber flange out of the groove and so there is leakage from the water heater/boiler. Although of a relatively low cost, a mechanism of this type eventually turns out to be expensive due to the problems and disadvantages arising thereby.
Amongst support mechanisms for water heaters, however of the open circuit type, wherein water is circulated under low pressure, DE-A-3805 559 discloses a water heater which is made of synthetic material. Normally water heaters of the open circuit, low pressure type are made as a single piece, of any shape, such as the rectangular section of the water heater disclosed in DE-A-3805 559, which provides for water inlet and outlet pipes through the same central end opening of the heater that is used for the introduction of the heating resistor and of the magnesium rod. DE-A-3805 559 proposes a support mechanism for the electric resistance consisting of a cap, a rim, a tubular bolt bearing inner threading, a tubular bolt with an outer threading and a metal flange whereupon are mounted the electric resistance and the magnesium rod.
Such type of support mechanism creates difficulties in case that the electric resistor has to be replaced, because in such a case one has to disconnect the water inlet and outlet pipes as well. To enable such disconnecting, water inlet and outlet pipes are given a bent shape in DE-A-3805 559, whilst the tubular bolt with outer threading is made in two pieces.
The object of the present invention is a water heater/boiler of high pressure closed circuit type having a support mechanism with an electric resistance and magnesium rod wherein a cap is of hemispherical section to withstand high pressures being provided with an outward bent rim which constitutes the base upon which sits a metal flange onto which are mounted the electric resistance and magnesium rod, wherein a tubular nut with an internal threading is removably mounted around the rim of the cap and wherein a tubular bolt made from a compact cylindrical tube with external threading is rotated via a circumferential arrangement of holes thereof, so that its external threading engages with the internal threading of the tubular nut, thereby pressing and effecting firm mounting of the metal flange.
The invention will be made apparent by reference to the accompanying drawings, in which:
Fig. 1 shows a cross sectional view of the support mechanism of the electric resistance in accordance to one application of the prior art.
Fig. 2 shows a cross sectional view of the support mechanism of the electric resistance in accordance to yet another application of the prior art.
Fig. 3 shows a cross sectional view of the support mechanism of the electric resistance in accordance with the invention.
Figs 4A and 4B show a cross sectional view of the support mechanism of the electric resistance in accordance with the invention, wherein the tubular nut is welded onto cap 2.
Fig 5 shows a perspective view of the series of individual parts used in the support mechanism of the invention.
Fig 6 shows a cross sectional and a plan view of the support mechanism of the electric resistance in accordance with the invention, wherein the tubular nut is mounted upon the cap by means of a plurality of dowels.
As depicted in Fig. 1, in accordance to one conventional application of the prior art, the outer end of the metallic cap 2 turns into a flat base 2a bearing eight holes, whilst the bottom end of cap 2 is soldered circumferentially onto the circular open bottom of water heater/boiler 1. A flange 4 with the electric resistance 5 and magnesium rod 6 is mounted onto the flat base 2a of cap 2 with the rubber flange 7 in between. Subsequently, bolts 17 and nuts 18 are used for pressing flange 4 onto the flat base 2a of cap 2 and the cap is thereby closed.
As depicted in Fig. 2, in accordance to one further conventional application of the prior art, the cap has a central opening, which is oval in shape, whilst the rim of the cap is formed with a circumferential groove wherein is seated the rubber flange 7. In this case an outer metal flange 4a is used which is connected with the inner metal flange 4 with the electric resistance 5 and magnesium rod 6, when fastened thereupon via bolts 17 and nuts 18, with the rubber flange 7 in between.
The disadvantages of both the above mechanisms of the prior art have already been disclosed in the introductory part.
In accordance to the invention, a tubular nut 3 with internal threading 3a in association with a tubular bolt 8 with external threading 8a is used for mounting the electric resistance 5 and magnesium rod 6 onto cap 2 of the water heater/boiler 1.
The advantage of this invention is that the inner surface of this new type of support mechanism of the electric resistance does not come into contact with the water inside the water heater/boiler 1. The apparatus therefore does not need any enameling (vitrification), but a mere coat of paint.
A further advantage of the invention lies in the fact that it secures a perfect waterproofing without creating bending of the metal surfaces during the tightening, thereby avoiding cracking of the enamel. Thus, the problem of oxidation and consequent uselessness of the entire water heater/boiler is eliminated.
In summarizing, the present invention solves the problem of cracking of the enamel in the inner surface of the cap, makes the installation and replacement of the electric resistance easier and ensures a perfect waterproofing. In this way, wear of the water heater/boiler is controlled and the whole apparatus is more durable.
The above advantages are obtained due to uniform pressing of the tubular bolt 8 onto metallic flange 4 with the electric resistance 5 and magnesium rod 6, which in turn uniformly presses upon the annular rubber flange 7 and against the outward bent rim 10 of the cap 2.
As illustrated in Figure 5, wherein are depicted in a disassembled array the various parts of the apparatus of the invention, the cap 2 of hemispherical section, typical for the high pressure closed circuit type water heater/boiler 1, is provided with an outward bent rim 10 around the central opening 16 thereof, whereupon sits the annular rubber flange 7 and metal flange 4, which is subsequently pressed via screwing of the tubular bolt 8 into the tubular nut 3. Screwing of tubular bolt 8 is effected via rotation of the same by means of a suitable tool introduced into anyone of a circumferential arrangement of openings 9 provided on the circumference of the tubular bolt 8. Rotation of tubular bolt 8 results in the engagement of the external threading 8a thereof with the internal threading 3a of the tubular nut 3, and in the subsequent pressing upon metal flange 4 with the electric resistance 5 and magnesium rod 6.
Subsequent Figures illustrate alternative embodiments of mounting the tubular nut onto cap 2 of the water heater/boiler 1.
In accordance with the invention (Fig. 3), the tubular nut 3 is provided with a bottom inwards projecting circumferential base 15 and the tubular nut 3 is mounted onto cap 2 when an elongated portion 2a of the cap rim is bent and circumferentially overlaps the bottom inwards projecting circumferential base 15 of the tubular nut 3.
According to figures 4A-4B, the tubular nut 3 is welded onto cap 2 of the water heater/boiler 1, the welding being effected by means of a circumferential arrangement of welding points 19.
The cap rim 10 around which is mounted the tubular nut 3 takes a semi-circular form in Fig. 4A, whilst the same has an outward bent curved form in Fig. 4B.
Fig. 6 shows the invention in which a plurality of metal brackets 11 are welded onto the cap in a circumferential arrangement around the tubular nut 3. The tubular nut 3 is provided with a circumferential arrangement of holes 14, which are coaxial with corresponding holes 12. of the metal brackets 11. Thus the tubular nut 3 is fixedly mounted onto cap 2 by means of a plurality of dowels 13 passing through the circumferential arrangement of holes 14 at the walls of the tubular nut 3 and subsequently through the corresponding circumferential arrangement of coaxial holes 12 provided onto metal brackets 11.

Claims

A water heater/boiler of the high pressure closed circuit type having a support mechanism with an electric resistance (5) and magnesium rod (6), the mechanism comprising a metal flange (4) whereupon are mounted the electric resistance (5) and the magnesium rod (6), a water heater/boiler cap (2) including a central opening (16) via which said electric resistance (5) and said magnesium rod (6) are introduced, whilst said metal flange (4) sits upon a rim of said central opening (16), an annular rubber flange (7) being introduced intermediately between said metal flange (4) and the rim, said metal flange (4) being pressed upon said rubber flange (7) and underlying rim of said central opening (16) by means of a tubular bolt (8) with external threading (8a) screwed within the internal threading (3a) of a tubular nut (3), characterized in that:

said cap (2) is of hemispherical section and provided with an outward bent rim (10) around said central opening (16) thereof, said rim (10) constituting the base upon which sits said annular rubber flange (7) and said metal flange (4), wherein said cap (2) is removably connected to the high pressure water heater/boiler of cylindrical section;

said tubular nut (3) is removably mounted upon said cap (2) and around said rim (10), and

said tubular bolt (8) is a compact cylindrical tube equipped with a circumferential arrangement of holes (9) via which and by means of a suitable tool said tubular bolt (8) is rotated so that said external threading (8a) of said tubular bolt (8) engages with said internal threading (3a) of said tubular nut (3) and thereby said tubular bolt (8) is screwed within said tubular nut (3) and presses upon said metal flange (4).
A water heater/boiler as claimed in Claim 1, wherein said tubular nut (3) is mounted upon said cap (2) by means of a circumferential arrangement of welding points.
A water heater/boiler as claimed in Claim 1, wherein said tubular nut (3) is mounted upon said cap (2) by means of a plurality of dowels (13) passing through a circumferential arrangement of a plurality of holes (14) at the walls of said tubular nut (3) and through a corresponding circumferential arrangement of a plurality of coaxial holes (12) provided onto metal brackets (11) welded upon said cap (2).
A water heater/boiler as claimed in Claim 1, wherein said tubular nut (3) is mounted upon said cap (2) by means of the cap rim extending into an elongated portion (2a), said elongated portion (2a) circumferentially overlapping a bottom inwards projecting circumferential base (15) of said tubular nut (3).