RU1794285C - Waveguide chamber for thermal treatment of dielectrics - Google Patents

Abstract

Usage: for pasteurization and sterilization of physiological solutions, juices, dairy products and other liquids, heating and thawing foods, drying asbestos, wood, other building materials, vulcanization, rubber products, etc. The invention: a waveguide chamber for heat treatment of dielectrics, containing a waveguide segment consisting of the first and second metal pipes of rectangular cross section, the wide walls of which are parallel, and the narrow ones are located in the same plane, in the narrow walls of a howl and a second metal pipe located in one of the planes, slots are made along the entire length, the corresponding edges of which are connected by metal walls .; which form a channel for the material to be processed, the metal walls connecting the corresponding edges of the slots in the cross section are in the form of arcs of concentric circles.

Description

The invention relates to .tc microwave technology, in particular, to the / direction of microwave energy associated with the use of wave-wave paths as basic elements of working chambers For conveyor heat treatment of dielectric materials :: v j.;;;;. ;; : V

There are known designs of chambers for heating dielectrics in a microwave field based on waveguides of the simplest sections. Thus, a setup is carried out in which it is dried. the film is transported inside pr - -; angular waveguide along its axis; perpendicular to a wide wall; a chamber in the form of a meander structure on a rectangular waveguide, bent at a right angle: along a wide wall, for microwave drying of wide tape materials is described. In these devices, the dielectric being processed is located in the region of maximum

: electric field of the main wave Hio.

A prototype of the proposed device is a waveguide chamber of a microwave conveyor heating installation based on a P-waveguide. Interaction space

: The quasi-Nude type traveling wave field with a dielectric is the capacitive gap. Use-; The formation of a U-shaped profile causes an increase in the electric

.the floor in the space take action and, as a consequence ;: there is an intensification of the processor-heat treatment. ; . /.

 The disadvantage of this design is that when operating at a standard frequency of microwave energy of 915 MHz, its dimensions are sufficiently large (the size of the wide waveguide wall is from 15 to 35 cm), and this determines the high metal consumption of the installation. In Ustg

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The property cannot heat treat liquid or bulk materials - the processed product moves in the chamber along a chain conveyor. Finally, the P-waveguide camera can by no means always be used for microwave heating of materials whose dielectric constant substantially changes during the heat treatment, since this requires, as a rule, a wider single-mode band than that which is characteristic P-waveguides.

The purpose of the invention is to increase the width of the width of the waveguide chamber for heat treatment of dielectrics, to reduce its size, to enable heat treatment of liquid and bulk materials while maintaining a high process intensity. Using the invention, it will be possible to expand the class of dielectrics that can be subjected to uniform and highly efficient heat treatment in the same working chamber, both due to materials in various physical states and due to dielectrics with sharply changing permeabilities in the operating temperature range ; it is possible to reduce the metal consumption for the manufacture of the camera itself.

This goal is achieved by the fact that in the waveguide chamber for heat treatment of dielectrics containing a length of the waveguide, consisting of the first and second metal pipes of rectangular cross section, the wide walls of which are parallel and the narrow ones are located in the same plane, in the narrow walls of the first and second metal pipes, located in one of the planes, slots are made along the entire length, the corresponding edges of which are connected by metal walls that form a channel for the processed material. According to the invention, meta The face walls connecting the corresponding edges of the slots in the cross section are in the form of arcs of concentric circles.

This profile, in comparison with a rectangular and a round one, leads to higher values of the critical wavelengths of the main type and the coefficient of wide-width of the working chamber. In the general case, a waveguide with a capacitive gap can be obtained from a rectangular waveguide by introducing a regular metallic inhomogeneity in the maximum electric field of the Nu wave. However, in comparison, for example, with a U-shaped waveguide, the proposed waveguide is characterized by substantially larger values of the critical wavelengths of the fundamental mode. This provides a fixed frequency

heat treatment the smaller dimensions of the chamber on the waveguide line of the claimed profile than on the P-waveguide used in the prototype, and also makes it possible to heat treat more voluminous materials with a wide range of changes in the operating temperature range. It is characteristic that, when the material e changes, the resulting variations in the deceleration of the heat-treating wave

quasi-Nu does not lead to noticeable distortions in the uniform distribution of the electric field in the capacitive gap.

The drawing shows a possible cross section of a waveguide chamber

for heat treatment of dielectrics,

As an example of a specific embodiment, a chamber for pasteurizing or sterilizing liquids (physiological saline, food, etc.) may be described. The developed project provides for its operation as part of a microwave pasteurizer of milk protein concentrate. Installation parameters: generator frequency 2450 MHz, its power up to

4 kW; chamber dimensions: a wall is wide 13 cm, narrow 6 cm, the diameter of the internal arc bounding the capacitive gap 4 cm, the height of the gap 2 cm

Milk-protein concentrate obtained in the process of ultrafiltration at 40 ° C enters the channel of the working chamber; while its permeability to 55. During the movement along the waveguide, the concentrate is heated to pasteurization temperature

80 ° C (Ј while decreasing to about 40 °), after which it is brought out. The outlet temperature is set either by adjusting the power of the generator or the speed of movement of the material inside

cameras, Estimates show that the performance of this installation is not less than 150 l / h.

Due to the increased electric field strength in the interaction space, the camera built using the described device has an increased (compared to the traditionally used - on) performance and small dimensions, and

consequently, a reduced (5-10%) metal consumption of the structure.

Claims (1)

SUMMARY OF THE INVENTION A waveguide chamber for heat treatment of dielectrics, comprising a length of a waveguide consisting of first and second metal pipes of rectangular cross section, the wide walls of which are parallel and the narrow ones are located in the same plane, in the narrow walls of the first and second metal pipes located in one of the planes , slots are made along the entire length, the corresponding edges of which are connected by metal walls that form a channel for the material to be processed, characterized in that, in order to increase the width In order to reduce the space and reduce dimensions, to provide the possibility of heat treatment of liquid and bulk materials while maintaining a high intensity of the process, the metal walls connecting the corresponding edges of the slots in the cross section are in the form of arcs of concentric circles.  / / / / / //