SU995386A1 - Fluidic medium heater - Google Patents

Description

(54) ELECTRIC HEATER OF THE FLOW ENVIRONMENT

one.

The invention relates to electrical engineering, in particular to electric heaters, designed to heat a gas.

Known electrical fluid heater with electrical resistance in the form of a metal tape, fixed insulators, made in the form of two insulated metal supports 1.

The disadvantage of the known apparatus is the poor heat exchange of the heated medium with the metal tape of resistance, local overheating of the metal tape due to the fact that not all layers of the flow are gas: they flow around the resistance tape, there is no flow turbulization; In addition, at the place of adherence of the metal tape, the resistance and insulators are not blown by its heated gas, and heat exchange takes place through the insulator. The specified device also has insufficient reliability in operation. The disadvantage is due to the fact that the metallic tape of resistance with heating / ve lengthens and its slipping from the insulators into the interturn circuit can occur, which will lead to the failure of the electric heater.

Closest to the present invention is a fluid electric heater, comprising a housing, heating elements of resistive tape fixed therein, wound in the slots of insulators mounted on the fastening fittings 2.

A disadvantage of the known device is the poor heat exchange of the heated medium with a metal tape of resistance and local overheating of the metal tape due to the fact that not all layers of the gas flow flow around the metal tape, there is no turbulizac gas flow. In addition, in places where the metal strip fits against the insulator, it is not blown by heated

15 by gas, and heat exchange takes place through an insulator. In addition, the known device is not sufficiently reliable in operation, since the metal tape lengthens during heating and interturn lock can occur. And also with local destruction

Claims (2)

 one of the insulators can occur interturn circuit and the heating device goes out of order. In this case, it is necessary to replace the entire insulator and completely rewind the resistance tape. The purpose of the invention is to intensify heat transfer and increase reliability. The goal is achieved by the fact that in an electric fluid heater insulators are made of a set of elements arranged in a checkerboard pattern and are provided with transverse grooves on the side of the groove for winding made with a radius smaller than the radius of winding and longitudinal grooves on the side of the fixture made in in the form of two pipes coaxially arranged and fixed one relative to the other, internally of which is provided from the outside with protrusions included in the marginal grooves of the insulators. FIG. 1 shows an electrical heater, a general view, a section; in fig. 2 - isolator, section; in fig. 3 is a section A-A in FIG. 2, in FIG. 4 is a section BB in FIG. I. In the electric heater body 1, elements 2 of metallic resistance tape wound with a radius Ri of winding in the slots 3 of insulator 4 located on the protrusions 5 of the inner tube 6, which are included in the longitudinal groove 7, are made in the insulator 4 on the side adjacent to supporting fixtures. The pipe 6 is closed by a plug 8 and, by means of the corner 9, is fixed (by welding or any other type of connection) with respect to the external pipe 10, which is connected (by welding or in any other way) to the blank grille 11 and the latter to the housing 1. In the insulator 4 3 are made along the radius R 2 less than the radius of the winding of the tape, and in the center of the grooves 3 are made transverse grooves 12, which are located under the heating elements 2 (Fig. 2). The electric heater, for example, with a capacity of 300 kW operates as follows. Gas from above, for example, 3000 with a temperature of 473 K, is supplied to the housing 1 from above. The gas is distributed over the annular space between pipes 6 and 10; the heating elements 2 flow around the heating element; it heats up and leaves the annular space from the other side with a temperature of, for example, 723 K. In the annular gap between the pipes 6 and 10, due to the staggered arrangement of the insulators 4, the gas flow is turbulized, improving heat transfer, and the heat transfer coefficient increases, which makes it possible to reduce the size of the apparatus. Heat transfer from the heating elements 2 to the heated gas is carried out over the entire surface of the metal strip, i.e. the gas flows around the entire surface of the heating elements. 2. This is achieved due to the presence of transverse grooves in the grooves 3, which are located under the heating elements 2, and also because the grooves 3 are made with a radius Rz smaller than the radius Ri of the winding of the heating element 2. At the same time, the heating elements 2 are fitted to the insulator 4 with only one line - the longitudinal generatrix. Due to the complete blowing of the heating elements 2 and intensive heat exchange, the temperature of the heating elements 2 is the same in all areas, optimal and local overheating is excluded. This increases the reliability and durability of the electric heater, as well as reduces the size of the device. In the case of the destruction of the insulator 4, the heating elements 2 are securely fixed on the adjacent insulators and protected against inter-turn closure, and the destroyed insulator 4 is easily replaced with a new one. The outer tube 10 is connected to a hollow grid 11, blocking the path to the flow of heated gas, by means of which the entire structure is connected to the housing 1 with the possibility of disassembling it. The lower ends of the pipes 6 and 10 and heating elements have free movement, which prevents thermal deformation and increases the reliability of work. The heated gas exits the electric heater from below. The proposed heater design allows to intensify the heat exchange and increases the reliability of the heater in operation. Claims of the Invention An electric fluid heater comprising a housing, heating elements fixed therein of a resistive tape wound in insulator slots mounted on fixing armature, characterized in that, in order to intensify heat exchange and increase the reliability of the structure, the insulators are made of a set of elements staggered, and provided with transverse inlets on the side of the groove for winding, made of a radius smaller than the radius of winding, and longitudinal grooves on the side of the mounting ar matura, made in the form of two coaxially arranged and fixed one relative to the other pipes, internally of which is provided outside with protrusions included in the longitudinal grooves of the insulators. Sources of information taken into account in the examination 1.Patent of France No. 1335339, A 61 N 1970. 2. The patent of France No. 1207053, H 01 C, 1966. 6 9 eleven g