RU2044604C1 - Method and apparatus for producing compacted articles from ceramic at high pressures in burning mode of operation - Google Patents

Abstract

FIELD: plastic working of materials. SUBSTANCE: method involves inserting punch 2 into die 1 and pouring basic burden 14; positioning die with punch and burden into working cavity A of container 3; closing shutters 4 and biasing them by supporting frame 5; starting on control system with programming device 8; switching on gas supply system 9 with valves 11,12,13 being opened and valve 10 closed, to fill cavities A and B of container with gas (nitrogen, argon carbon dioxide gas) to predetermined pressure. When valves 11,12 are opened and valves 10,13 are closed, burning of burden 14 is initiated by initiating system 7. Upon expiration of predetermined delay time, valves 11,12,13 are closed and valve 10 is opened to relieve gas from working cavity A. Sample is pressed by pressure differential in cavities A and B. Gas pressure is applied through cylinder 6 and punch 2 to burden 14. Upon expiration of predetermined delay time valves 10,11,12 are opened under pressure and valve 13 is closed. In this case gas is relieved from both cavities of container. Then frame 5 is shifted away from shutters to open shutters 4 and die is withdrawn. EFFECT: increased efficiency and improved quality of ceramic articles. 1 dwg

Description

 The invention relates to the field of production and processing of refractory inorganic materials in the combustion mode of the components of the reaction mixture in a reacting gas atmosphere at high gas pressure and can be used for the manufacture of products of their ceramic materials by combining self-propagating high-temperature synthesis (SHS) and subsequent compaction.

 A known installation for the synthesis of carbide products [1] comprising a press with a table, a reaction mold with a hollow body, a heat-insulating shell, an initiating spiral and a base, forming punches, gas channels, a time delay device and a control system.

 The main disadvantage of this installation is the lack of a high-pressure container, which makes it impossible to obtain ceramic products on it.

Closest to the proposed is the installation for compact products from nitride ceramics in the combustion mode [2]
The installation includes a power frame, a container with gates, a gas supply system, a control and management system, a combustion initiation system, a press with a table, a reaction mold with punches, heat shields, a cooling system and a heater.

 The main disadvantage of the prototype is the low pressure of the reacting gas, which does not allow to obtain products of the required purity at this installation due to the incomplete reaction of the materials.

 The aim of the invention is to improve the quality of the products.

 The goal is achieved by the fact that in the installation for compact ceramic products at high gas pressures in the combustion mode, containing a power frame, a container with valves, a reaction mold with punches, a control system, a combustion initiation system and a gas system, the container cavity is divided into two separation by a wall with a through hole in which a movable cylinder is installed, installed with the possibility of interaction with one of the punches, the control system is equipped with a software device, and in the gas system In addition, high-pressure solenoid valves connected to the software device have been introduced.

 The essence of the claimed invention is as follows.

 The reaction mold with punches allows pressing after the passage of the combustion wave. The wall separating the container allows you to create a pressure differential between the cavities of the container. A through hole in the wall, into which a movable cylinder is installed, which transfers force to one of the punches, allows you to turn the gas pressure into a mechanical force for pressing products. In addition, electromagnetic valves introduced into the gas system make it possible to create a pressure differential in the container cavities. The control system, equipped with a software device that commands the solenoid valves, automates the pressing process. The combination of all the features of the installation can improve the quality of the products by reducing their porosity.

 The drawing shows a diagram of the proposed installation.

 Installation for producing compact ceramic products at high gas pressures in the combustion mode contains a reaction mold 1, punches 2, container 3, closures 4, a supporting frame 5, a movable cylinder 6, a combustion initiation system 7, a control system 8, a gas system 9, high pressure solenoid valves 10-13, initial charge 14.

 The container includes two cavities: A working volume, B prepress volume.

 Installation works as follows.

The lower punch 2 is inserted into the reaction mold 1 and the initial charge 14 is poured. Then the mold with the punch and the charge is placed in the working volume A of the container 3. Then the closures 4 are closed, pressed by the supporting frame 5. After that, the control system 8 with software device. Further, the control system operates according to the following program:
I. Valves 11,12,13 are open, valve 10 is closed. The gas system 9 is turned on and both compartments of the container are filled with gas (nitrogen, argon, CO ₂ ) to the required pressure (1-5000 atm).

 II; Valves 11,12 are open, valves 10,13 are closed. Initiation of combustion takes place in the initial charge 14 using the initiation system 7.

 III. After a predetermined (depending on the charge composition) delay time (0-120 s), valves 11,12,13 are closed, valve 10 is open. The gas is vented from the working volume A and at the same time the sample is pressed due to the pressure difference in the volumes A and B. The gas pressure is transmitted through the cylinder 6 and the punch 2 to the initial charge 14.

 IV. After holding time under pressure (0-60 s), valves 10,11,12 are open, valve 13 is closed. There is a complete bleeding of gas from both cavities of the container.

 Then the supporting frame 5 is retracted, the shutter 4 opens, the mold is removed and the resulting product is pressed out.

 The combination of these installation elements provides the ability to obtain non-porous ceramic products in one operation without preliminary pressing and on one installation, which improves the quality of the products.

 The proposed installation allows to obtain ceramic products, almost non-porous (density 98-100% of theoretical), with a high uniformity of structure, which is ensured by pressing the workpiece immediately after the passage of the combustion wave.

 The basic object to the claimed installation is the installation adopted as a prototype [2] The disadvantage of the basic object is the insufficient purity of the resulting ceramics due to the low pressure of the reacting gas. Compared with the base object of the claimed installation provides a wide range of products both in porosity and in composition, which improves the quality of the products. Installation is very easy to maintain.

Claims (1)

 INSTALLATION FOR PRODUCING COMPACT CERAMIC PRODUCTS AT HIGH GAS PRESSURES IN THE COMBUSTION MODE, comprising a power frame, a container with shutters, a reaction mold with punches, a control system, a combustion initiation system and a gas system, characterized in that, in order to improve the quality of the products obtained , the container cavity is divided into two compartments by a wall with a through hole in which a cylinder is installed, which is installed with the ability to move and interact with one of the punches, while the control system polyene with programming device and the gas system with a high-pressure electromagnetic valves connected to the programming device.