RU126583U1 - KETTLE OR THERMOPOT WITH GRID FOR NOISE REDUCTION - Google Patents

Abstract

1. A kettle or thermo sweat for heating water, including a water tank and a heating surface, which is located in the lower part of the tank, characterized in that the heating surface is covered with a grid, or a grid, or a perforated plate from the side of the heated medium. 2. A teapot or a thermo sweat according to claim 1, characterized in that only the peripheral part of the heating surface is covered with a grid, or a grid, or a perforated plate. A teapot or a thermal sweat according to claim 1, characterized in that the width of the mesh cell, or lattice, or hole in the perforated plate is from 0.7 to 1.2 mm. Kettle or thermo sweat according to claim 1, characterized in that the heating surface is covered with two layers of mesh, or lattice, or perforated plate. A teapot or thermo sweat according to any one of claims 1, 2, 3 or 4, characterized in that the grid, or lattice, or perforated plate is fixed to the heating surface by means of welded joints. 6. A teapot or thermo sweat according to any one of claims 1, 2, 3 or 4, characterized in that the mesh, or lattice, or perforated plate is made in the shape of a circle and is fixed in a ring that is fixed inside the container. 8. A teapot or thermo sweat according to claim 6, characterized in that the ring is fixed inside the container with the possibility of disconnecting and removing the ring together with the net from the teapot or heat sweat. Kettle or thermo sweat according to claim 7, characterized in that the rods are cantilevered to the ring to press the mesh against the heating surface. A kettle or a thermo sweat according to claim 7, characterized in that the heating surface has a convex shape from the side of the heated medium.

Description

The utility model relates to household appliances, and in particular to devices for heating water - kettles, electric kettles and thermal pots.

A known kettle for heating water, including a water tank and a heating surface, which is located in the lower part of the tank, through which heat is supplied to the water from an electric or gas stove. Known electric kettle, which differs from ordinary in that the heat to the heating surface is supplied from a tubular electric heater (TEN). A thermal sweat is known, which differs from an electric kettle in that the vessel has better thermal insulation from the environment. All of these devices are well known and do not require detailed specifications. All of these water heating devices include a water tank and a heating surface, which is located at the bottom of the tank.

Known teapots with a reduced noise level, in which the effect is achieved by imparting a large roughness to the heating surface due to mechanical processing, sandblasting, or coating the surface with a layer of particles [1, 2, 3]. All these methods are too complicated and not too effective, since it is difficult to obtain the desired surface shape in such ways to stabilize the formation and growth of bubbles.

As a prototype, a kettle or thermo sweat for heating water was selected, including a water tank and a heating surface, which is located in the lower part of the vessel.

The technical result of the utility model is to reduce the noise of a kettle or thermal sweat.

A kettle or thermo sweat for heating water includes a water tank and a heating surface, which is located at the bottom of the tank. In order to get the effect of noise reduction, it is enough to cover the heating surface of the kettle or thermo sweat with a mesh or grill or perforated plate on the side of the heated medium.

Since the heater is often located only in the peripheral part of the heating surface, only the peripheral part of the heating surface can be covered with a grid or grating or perforated plate.

The best result is achieved when the mesh width of the mesh or lattice or the hole of the perforated plate is from 0.7 to 1.2 mm.

The heating surface may be coated with two layers of mesh or grating or perforated plate to achieve a greater effect.

The mesh or grating or perforated plate may be fixed to the heating surface by means of welded joints.

Also, the grid or grid can be made in the form of a circle and fixed in a ring, which in turn is fixed inside the tank. The heating surface may be convex towards the heated medium to ensure the mesh is pressed against the heating surface, or the mesh may be pressed to the heating surface using rods that are cantilevered on the ring.

It may also be possible to disconnect and remove the ring along with the net from the kettle or thermal sweat.

The principle of noise reduction is the same as when using rough surfaces of various kinds [1, 2, 3], but covering the surface with a mesh is much simpler and more efficient.

Figure 1 on the left shows a conventional electric kettle, comprising a housing 1 and a round heating surface 2 at the bottom of the kettle. The heating surface is covered with a mesh or a grid or a perforated plate 3. On the right are shown in larger detail: a grid 3a, a grid 3b and a perforated plate 3c.

Figure 2 illustrates the processes of surface boiling with underheating. On the left is the boiling process without a net (a). On the heating surface 2, bubbles 4 are formed and condense, no active vaporization is observed. In the center, the boiling process is depicted (b) with a grid of 3. Large bubbles large enough to detach form on the heating surface; the process of vaporization is active. The right side shows the distribution of the liquid temperature tl along the height of the vessel N for a process without a grid and with a grid. The liquid temperature is plotted along the abscissa and the wall temperature tct and water saturation temperature tn are marked; the ordinate shows the height above the heating surface. The graph shows the dependence for boiling without a grid tzh (a) and with a grid tzh (b). The graph illustrates the fact that when boiling with a grid near the surface there is a thick layer of liquid superheated above the saturation temperature.

The utility model is highly technological and easy to use. The heating surface in a teapot or thermo sweat is now always a flat disk. It is enough to cover the heating surface 2 with a grid 3a (see FIG. 1) and fix it to the heating surface by contact welding or attach to a ring, which in turn is attached to the heating surface or to the walls of the vessel.

For these purposes, a conventional stainless steel mesh with a cell width of 0.5 ÷ 2.0 mm [4] is suitable. The best result can be achieved with a cell width of 0.7 ÷ 1.2 mm.

Noise reduction is achieved by stabilizing the formation and growth of vapor bubbles. According to the definition, boiling is the process of steam formation inside the volume of a liquid heated above the saturation temperature [5]. Boiling in a teapot can be characterized as surface boiling with under-heating of the liquid [6]. In the kettle, the temperature of the liquid is significantly warmed up to the saturation temperature during the entire work cycle, with the exception of only the last stage of intense boiling, which lasts only a few seconds and is characterized by low noise.

Consider the process of boiling in a kettle without using a grid. After switching on the kettle, the water in the vessel was initially not heated to saturation temperature, only near the surface a thin boundary layer was formed, the temperature of which was higher than the saturation temperature (see figure 2). In the centers of vaporization, which are microcracks on the heating surface, small vapor bubbles arise. Since the boundary layer is very thin, the bubbles instantly condense, after which new bubbles begin to grow in microcracks. Thus, when boiling a kettle, each microcrack is a source of hydraulic vibrations.

Many bubbles of very small diameter constantly appear and condense on the heating surface, which leads to the appearance of loud noise.

In the process of heating water, the total temperature increases, boiling becomes more intense, which leads to intensive mixing of water in the vessel and thinning of the boundary layer [6]. As a result, even with a slight underheating, the kettle continues to create a considerable noise.

Consider the process of boiling a kettle with a grid on the heating surface. The grid performs several functions at once: it creates centers of vaporization in places of contact with the heating surface, prevents thinning of the boundary layer during intense boiling, and develops a heat exchange surface.

The surface area of the grid covering the heating surface is almost one and a half times larger than the area of the heating surface itself, so the grid is very conducive to improving heat transfer. Due to this, the temperature of the liquid in the mesh cells increases significantly (see figure 2). Bubbles also form on the heating surface, but now they are in a layer of water superheated above the saturation temperature, so they quickly reach the dimensions required for separation (0.5 ÷ 1.0 mm), come off and float.

When boiling with a net, one can observe active vaporization from the very beginning of the kettle. Bubbles overheat in the boundary layer above the saturation temperature and overcome the thickness of cold water without condensing. Due to the active vaporization in the vessel, intensive mixing of the liquid occurs, but thanks to the grid, the boundary layer is preserved.

The effect is confirmed experimentally with grids with a cell width of 0.7 mm, 1.2 mm and 2.0 mm. In all cases, a significant noise reduction effect was achieved. A similar result can be obtained if not a grid is used, but a grid or a perforated plate with the same cell size (see Fig. 1)

Bibliography:

1. Patent GB2386532A, IPC1-7: A47J 27/21; Н05В 3/80. Electric water heater with reduced noise level [Text] / Johnston Simon Richard, Applicant STRIX Ltd. Date of publication - September 17, 2003.

2. Patent GB2411332A, IPC1-7: A47J 27/21; A47J 36/02; HB05 3/78. Noise reduction in water heating vessels [Text] / Johnston Simon Richard, Scott Michael James, Applicant STRIX Ltd. Date of publication - 08.24.2006.

3. Patent GB2445070A, ECLA: A47J 27/21 B2; H05B 3/82. Noise reduction in electric water-heating vessels [Text] / Wright Peter H; Mottram Andrew; Gaeta Antonio Martin; Ashmore Andrew Karl, OTTER CONTROLS Ltd. Date of publication - 06/25/2008.

4. GOST 3826-82. Woven wire mesh with square cells. Specifications [Text]. - Enter. 1984-01-01. - M .: Publishing house of standards, 2003.

5. Tsvetkov F.F., Grigoryev B.A. Heat and mass transfer: Textbook for universities [Text]. - 2nd ed. corrected and additional - M.: Publishing House MPEI, 2005. - 550 p., ill. ISBN 5-7046-1270-9.

6. Isochenko V.P., Osipova V.A., Sukomel A.S. Heat Transfer: A Textbook for High Schools [Text]. - 3rd ed. reslave. and add.- M .: "Energy", 1975. - 488 p., ill.

Claims (9)

1. A teapot or thermo sweat for heating water, including a water tank and a heating surface that is located in the lower part of the tank, characterized in that the heating surface is covered with a grid, or a grid, or a perforated plate from the side of the heated medium. 2. The teapot or thermo sweat according to claim 1, characterized in that only the peripheral part of the heating surface is covered with a grid, or a grid, or a perforated plate. 3. The teapot or thermo sweat according to claim 1, characterized in that the width of the mesh cell, or lattice, or hole in the perforated plate is from 0.7 to 1.2 mm. 4. The kettle or thermo sweat according to claim 1, characterized in that the heating surface is covered with two layers of mesh, or lattice, or perforated plate. 5. A teapot or thermo sweat according to any one of claims 1, 2, 3 or 4, characterized in that the grid, or lattice, or perforated plate is fixed to the heating surface by means of welded joints. 6. A teapot or thermo sweat according to any one of claims 1, 2, 3 or 4, characterized in that the mesh, or grating, or perforated plate is made in the shape of a circle and is fixed in a ring that is fixed inside the container. 7. The teapot or thermo sweat according to claim 6, characterized in that the ring is fixed inside the container with the possibility of disconnecting and removing the ring together with the net from the teapot or heat sweat. 8. Kettle or thermo sweat according to claim 7, characterized in that the rods are cantilevered to the ring to press the mesh against the heating surface. 9. Kettle or thermo sweat according to claim 7, characterized in that the heating surface has a convex shape from the side of the heated medium.

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