DE3302679A1 - Swing-out, electrically heated precision furnace - Google Patents

Abstract

Published without abstract.

Description

1. Description

Title: Hinged, electrically heated precision furnace Area of application: The invention relates to a hinged, electrically heated precision furnace, for various scientific and technological process and experimental procedures can be used.

For example: Rapid, precise heating of materials and samples Use in hot tensile tests on tearing machines Liquefaction and evaporation of Substances Melting and heating processes in the field of solar energy conversion Thermal Processes in the nuclear sector The list does not claim to be complete.

A currently preferred application is the foldable, electric one heated precision furnace for hot tensile and tensile tests of material samples. here especially in the case of short-term tensile tests in contrast to long-term tests which these ovens can also be used in a closed version.

Purpose: In the hot tensile test, hinged, electrically heated Precision furnace material samples heated under controlled thermal conditions, in order to determine the mechanical and physical values of the the respective material can be determined experimentally. In the case of short-term attempts preferably hinged ovens are used, since the attachment of the sample (17) Fig. 1 and 2 and the measuring rod (19) is hereby made much easier.

State of the art: According to the state of the art, this is already used closed and hinged ovens. The maximum operating temperature is usually 12000C.

Criticism of the state of the art: The conventionally used ovens show Disadvantages, individually or in their entirety, according to the following list may occur: 1. The heating resistors are relatively heavy ceramic masses embedded around pipes or in supporting stones.

This results in thermal inertia which causes an exact temperature control is practically impossible, even with the greatest control effort or is only achieved after very long heating and holding times.

These are tests in the lower and medium temperature range particularly affected.

2. To counteract the undesirable thermal inertia of the furnaces, small grooved bearing blocks made of pressed and sintered refractory masses are also used used. However, these stones only allow very thinly wound heating resistors with thin wires by 1 mm in diameter. Due to the applicable construction guidelines and experience in the construction of heating resistors, these resistors are for the temperature range above 7000C completely unsuitable.

3. The heating-up time for heat rupture tests is longer with conventional ones Ovens too long 4. The energy consumption of conventional ovens is too high.

5. Replacing heating resistors often requires a total Dismantling the ovens.

Task: The invention is based on the object, as possible to achieve rapid and, above all, uniform heating of the sample (17) Fig. 1 and 2, without overshooting the control loops due to unnecessary thermal ballast mass (Temperature deviations from the target value) the experiment is falsified.

Furthermore, a shorter heating-up time with lower energy consumption at the same time become possible. The furnace should be easy to use and unproblematic in maintenance and be repair. Likewise is a solid overall construction with a good technical To strive for design. The basic concept of the furnace should also be used for other scientific purposes and technological processes become usable.

Solution: According to the invention, the problem is solved by that with specially developed insulating bricks (2) Fig.lu.2 and using specially shaped heating resistors (1) (3) a powerful and robust heating system is produced with minimal storage capacity. The insulating stone can be made of composed of preformed insulating stone disks, carved out of the full block or made from unshaped masses. With a manufactured in this way Heating elements can also be safely controlled at high temperatures. In a modified version, this furnace can also be used under approximately the same Design of the heating system (Fig. 1 and 2) (1) and (2) for larger inner diameters be built according to Fig. 1 half section k. In this modified version was the semicircular, bowl-shaped heating element (1) and (2) by a trapezoidal heating element (3) and (4) replaced. This possibility of variation is based on the basic structure and the mode of operation of the invention has no effect.

Achievable benefits; The advantages achieved by the invention exist essentially: 1. Exact temperature behavior in the heating, holding and regulating process.

2. Shortened heating-up process with the option of doing it in the same time to carry out twice as many tests in hot tensile tests than with conventional ones ovens is possible.

3. Approx. 30% lower energy consumption 4. High operational reliability also in the upper temperature range over 10000C through the use of resistance wire of at least approx. 3 mm in diameter.

5.Improved outside temperature conditions with approx.

0 0 80 C compared to 100 C for conventional ovens.

6. Easy replacement of heating coils possible.

7. Versatile mounting options, low weight and solid Industry design.

8. Versatility in scientific and technological Area.

Description of the design: In Figures 3 and 4 the design of a hinged, electrically heated precision furnace is shown. Fig. 5 shows the associated technical characteristics.

Figs. 1 and 2 characterize the basic structure.

Fig. 1 shows in the section half A a modified embodiment the cut half B. The function and mode of operation as well as the principle inner and external structures are not affected.

The oven can be opened around the hinge point (9). about foldable Locking screws (11) with star grip (10) close the furnace. Handles with Ball knobs (12) make handling easier.

The insulating blocks (2) or (4) are separated from the insulating layers (13) and (14) surrounded. The entire inner lining is held by the pressure plates (15). 3 thermocouples (20) can be radially attached to the sample via the thermocouple flange (16) (17) and to the tie rod (6). The sealing takes place in the folding axis by circumferential strip seals (5).

The upper tie rod (6) is surrounded by flexible seals that be pressed on by en two-part slides (8) or the screwable lids.

The lower tie rod (6) is closed by a sliding block (18). The openings for the measuring rod (19) and the pull rod (6) are cut out.

The connection ends of the heating resistors (1) or (3) are via bushings (22) led out opposite the operating side and covered by protective hoods (23).

The furnace jacket (24) and the screw-on lids (25) form the Furnace housing. The covers are provided with threaded holes (26) on all sides so that the fastening straps (27) can be attached either on the right or on the left.

Claims (1)

Patent claims preamble: Electrically heated precision furnace that can be opened Characteristic part: Characterized by the fact that by the combination of a special developed insulating stone with a specially shaped heating resistor Heating system was created, which is essential compared to conventional designs has technical improvements. Generic term of the dependent claim: Shorter, more compact, foldable, electrically heated precision furnace. Characteristic part of the dependent claim: characterized thereby, that a furnace was developed through the form shown in Fig. 3 and Fig. 4, which has the characteristics according to FIG. 5 in this order of magnitude.