RU2455113C1 - Gasostatic extruder - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to equipment intended for processing articles from discrete and solid materials at simultaneous or combined effects of high pressures and temperatures created in gas of gasostatic extruder working chamber, and for sintering in vacuum and impregnation at pressure. Said gasostatic extruder comprises frame and container stopped by top and bottom plugs to accommodate furnace insert making working chamber. Said container is connected with tight gas feed and discharge pipelines. Said frame and contained are bound together by high-strength tapes to make multilayer bearing carcass. Note here that first layers of said carcass feature smaller thickness and higher strength while next layers are made from tape of larger thickness. Note also that all said layers are wound with stretch.

EFFECT: reduced tape stretching and extruder weight.

2 dwg

Description

The invention relates to the field of creating equipment for processing industrial products from discrete and solid materials with simultaneous or combined exposure to high pressures and temperatures up to 2000 MPa of up to 2000 ° C created in the gas environment of the working chamber of a gas thermostat.

High pressure gas thermostats in a container up to 2000 MPa are made of three types: monoblocks with threaded plugs that seal the container on both sides and without a power frame, monoblocks with smooth plugs and a power frame to which the force is transmitted from the plugs that lock the container, and bushings with smooth plugs and a power frame, made with a winding of high strength tape and creating a preliminary stress-strain state in the frame and container elements.

The prestressing structure has several advantages:

- high reliability of the structure, eliminating fatigue and instantaneous failure, while in monoblock structures due to high stresses, the likelihood of cracks;

- the maximum stresses in the gasostat power elements from the generated pressure in the container do not exceed 2/3 of σ _t , while in monoblock structures they reach σ _t ;

- in the total weight of the structure, expensive high-strength forgings from alloy steel account for 1/4 of the weight (the rest is “inexpensive” high-strength tape 5 × 1 mm in size from 65G steel according to GOST 21997-77), while in monoblock structures high-strength alloy steel is almost 100%.

In the manufacturing process of gas thermostats with small container diameters for pressure from 500 to 2000 MPa, created by technology with a preliminary stress-strain state of the structure, significant problems arise. In such constructions, fastened by winding from high-strength tape, the first 10 ... 15 layers of winding must be carried out with a tension close to the ultimate strength stresses of the tape, and the subsequent ones with lower ones, in accordance with the calculated winding schedule and according to the readings of the tensor system of the winding device. In this case, the bending stresses in the tape are

σ _and = E × h / (2R),

where E is the elastic modulus of the tape;

h is the thickness of the tape;

R is the radius of the container sleeve, which is fastened with tape.

It can be seen from the formula that the smallest bending stresses in the tape can be obtained using a tape of smaller thickness, and the greatest stresses occur at small radii of the container.

The total stress in the tape is

Σσ = σ _and + σ _n ≤ [σ _t ],

where σ _and are bending stresses in the tape;

σ _n - tension in the tape during winding;

[σ _t ] - allowable stresses in the tape.

Therefore, the winding of the tape must be carried out with tension, at which the voltage in the tape does not exceed

σ _n ≤ [σ _t ] -σ _and .

The lower the bending stresses in the tape, the more tension you can wrap and not overload the tape.

As the formula and practice show, some problems that arise during the winding process can be solved using bays with a tape of different thicknesses and various strength groups, which are butt welded to continue winding.

A number of foreign firms, such as AVURE Technologies Inc., EPSI Inc. Develop gas thermostats with high-strength tape winding. However, they do not release gas thermostats to ultrahigh pressures (up to 2000 MPa) and therefore they do not encounter such a problem when winding.

The experience in manufacturing gas thermostats with small container sizes shows that tape winding with a constant thickness of 5 mm and a width of 1 mm leads to numerous breaks and, as a result, to weakening of the structure.

An analogue of the claimed invention is a gas thermostat ГИП 15 0-50-50 designed by OJSC AHK "VNIIMETMASH", developed in 2007 (drawing No. 24 - 1387051 SB). The gas thermostat is designed for a working gas pressure of 500 MPa. The gas thermostat has a 3-sheet power monorama, a 3-sleeve container, fastened with a tape in accordance with GOST 21997-77 (material - steel 65G, size 5 × 1 mm) of constant thickness, upper and lower tubes, hermetically closing the container. The sealed gas inlet is connected to a gas control system comprising locking, guiding, safety and indicating equipment. The gas thermostat has a top loading of the workpiece.

The disadvantages of the analogue:

- winding is made of high strength tape of constant thickness;

- large total stresses in the tape led to rupture of the tape in the first layers due to large bending stresses;

- due to the reduction of the tension force, in order to avoid breaks, the outer diameter of the container is increased;

- increased for technical reasons the mass of the container.

The prototype of the invention is a gas thermostat company "ASEA" (Sweden) with a container fastened with a high-strength tape, described in the book "Processes and equipment for gas-static treatment", G. A. Krivonos, A. D. Zverev, L. Yu. Maksimov. - M.: Metallurgy, 1994, p. 138. The thermostat-analogue contains a container fastened with a high-strength tape, with cooling channels made near the outer surface of the sleeve. For this, hexagonal rods are installed between the fastening winding and the outer surface of the sleeve along its generators. In this case, the winding is not isolated from the coolant.

The disadvantages of the prototype are:

- the ribs of the hexagons, on which the first turns of the winding rest, are the concentrators of the voltage of the tape, which does not allow winding with the highest possible tension, especially for small diameters of the sleeve;

- cooling water is not isolated from the fastening tape, which leads to its corrosion and reduce the life of the container;

- cooling channels made between the faces of the hexagons, in some cases are small for proper cooling of the container. Over time, they become clogged (as happened in the container of the ASEA gas bath installed in VILS OJSC), which leads to expensive repairs or container replacement.

The objective of the invention is the creation of reliable gas baths for processing industrial products from discrete, continuous and ultrafine materials with high (up to 2000 MPa) gas pressure.

The problem is solved in that the gas thermostat contains a frame and a container closed by upper and lower plugs, in which a furnace insert forming the working chamber is placed, while the frame and container are fastened by winding with high-strength tapes forming a multilayer power frame, and the container is connected to sealed supply pipelines and exhaust gases. The first layers of the power frame are made of winding tape of a smaller thickness of increased strength, and the subsequent layers of the power frame are made of tape of a larger thickness, while all layers of the power frame are made by winding with tension.

To solve the problem, the design of the power part of the gas thermostat (frame, container) is proposed, made with a winding of tape of variable thickness. The first layers, which account for the maximum stresses, are made with a tape of a smaller thickness and an increased (maximum - 3P) strength group, which are carried out with maximum tension, the subsequent (from the 15th ... 20th layer) can be made with a tape of a larger thickness and less (1P or 2P ) strength, which is somewhat cheaper, and since the total mass of the tape is% of the total mass of the structure, a significant saving in manufacturing costs is obtained.

The technical result is:

- in optimizing the winding of the gas thermostat container, excluding breaks in the tape during winding, in the uniform distribution of stresses across the layers of the wound tape,

- to increase the reliability of the gas thermostat due to the absence of critical voltages in the winding of the gas thermostat container, and as a result, high reliability and a long service life,

- in the application in the first layers of a high-strength tape of group 3P, but of a smaller thickness and in subsequent layers, butt welding of a tape less durable (groups 1P, 2P), but of a greater thickness, the minimum dimensions and weight of the container are achieved and, as a result, lower manufacturing costs.

The proposed thermostat is shown in graphical materials, in which Fig. 1 shows a gas thermostat with a container in section, and Fig. 2 as an information material shows a gas thermostat with a container, selected as a prototype.

The container 1 of the gas thermostat (Fig. 1) has a three-core core fastened with high-strength tape 2. The first layers of tape 2 are made of group 3P tape with a thickness of 0.5 ... 0.8 mm, the subsequent layers of tape 2 are made with tape 1 mm thick and 5 mm wide of strength group 2P. At the ends of the tape 2 are held flanges: upper 3 and lower 4. The container 1 is hermetically sealed with plugs: upper 5 and lower 6. In the lower plug 6 there are gas inlets 7 and 8, as well as current leads 9 for the furnace insert. The force from the internal pressure in the container 1 is transmitted through the plugs 5, 6 to the frame 10. The gas drive of the gas thermostat contains a compressor 11 with a hydraulic actuator 12, a control system 13 with a gas supply from the gas station 14 and a heat exchanger 15 with a supply 16 and an outlet 17 of cooling water.

The container 1 of the gas bath with a three-core core and a winding of tapes made of high strength steel is made as follows.

High strength tape 2 is wound around the bushings.

Winding tapes is as follows.

A roll of high-strength tape (for example, steel 65G) with a thickness of 0.5-0.8 mm, determined from formulas (1, 2), is wound up to 15-20 layers according to a pre-drawn winding program between the upper 3 and lower 4 flanges on pre-assembled container sleeves 1. After the roll ends, the butt of the end of the tape is welded with the next tape of greater thickness, for example 1 mm. After that, further winding of the tape of greater thickness is carried out according to a pre-compiled winding program. After winding the tape, the last layer of tape (its end) is fixed (fixed). All wound layers are tensioned.

The container 1 is hermetically sealed with the top 5 and bottom 6 plugs. In the lower plug 6, gas inlets 7, 8 are made, as well as a current lead 9 for the furnace insert. The pressure force in the container 1 is transmitted through the plugs 5, 6 to the power frame 10. A gas control system tube 13 is connected to the gas supply 7 of the lower plug 6. The gas is pumped into the container and evacuated at the beginning and end of the gas control cycle.

Thus, the proposed gas thermostat with a container having a two- or three-sleeve core, fastened with a high-strength tape of variable thickness, allows you to:

- winding with high strength tape at optimal voltage values;

- exclude in the first layers the total critical stresses leading to breakage of the tape;

- increase the reliability and service life of equipment;

- create the power part of the gas thermostat (container, frame) of optimal size and minimum weight;

- reduce the cost of manufacturing equipment.

Claims (1)

A gas bath containing a frame and a container, closed by upper and lower plugs, in which a furnace insert is placed that forms a working chamber, while the frame and container are fastened by winding with high-strength tapes forming a multilayer power frame, and the container is connected to sealed gas supply and exhaust pipelines, characterized the fact that the first layers of the power frame are wound from tape of a smaller thickness of increased strength, and the subsequent layers of the power frame are made of tape of a greater thickness, while all layers of the power frame are made are wound with tension.

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