Volume shrinkage control device for isostatic pressing formed green body

Abstract

The utility model relates to the technical field of carbon product production, and provides an isostatic pressing forming green body volume shrinkage control device which comprises a cold isostatic pressing machine cylinder body and a mold barrel, the mold barrel is arranged in the cold isostatic pressing machine cylinder body, and a cold isostatic pressing machine end cover is arranged at the top of the cold isostatic pressing machine cylinder body. An overflow device is arranged on the right side of the top of the cold isostatic pressing machine end cover, a pressure measuring device is arranged at the top end of the right side wall of the cold isostatic pressing machine cylinder body, and a pressurizing device with flow meters and a pressure relief device with flow meters are arranged at the bottom end of the right side wall of the cold isostatic pressing machine cylinder body. The flow of the emulsified liquid can be measured during pressurization and pressure relief, and the PLC system calculates the volume shrinkage of a formed product through the flow of the emulsified liquid entering the cylinder body of the press. In the pressurizing process, the pressure relief valve is in a closed state, and the flow meter can be used for detecting the leakage condition of the pressure relief device. In the pressure maintaining process, the pressurizing device valve is in a closed state, and the flowmeter can be used for detecting the leakage condition of the pressurizing device.

Description

TECHNICAL FIELD

[0001] The utility model relates to the carbon product production technical field, especially a kind of isostatic pressing forming green body volume shrinkage control device. BACKGROUND

[0002] The production process of special carbon graphite material is usually to grind coke particles into micron-level fine powder using a pulverizer, to mix and preheat the fine powder after batching according to certain batching requirements, to add molten liquid pitch to the mixed and preheated fine powder to form a paste, to form a paste block with a size less than 10 centimeters after cooling the mixed paste, to grind the paste block into fine powder with a size of tens of microns, and then to form a green body by molding or isostatic pressing, to form a special carbon material after baking the green body, and to form a special graphite material after further impregnation, secondary baking and graphitization.

[0003] Isostatic pressing is a new type of forming method, which has the advantages of high forming pressure, isotropy and the ability to press special-shaped parts compared with traditional molding, extrusion and vibration forming, and is widely used in the fields of special graphite, special ceramics and aerospace.

[0004] The cold isostatic press currently used in the special carbon industry has automatic pressurization and pressure compensation functions, and the maximum pressure can reach 200MPa, so that the formed product shrinks and densifies under a certain pressure for tens of minutes.

[0005] The forming pressure and pressure holding time of green bodies of different specifications are different, and the ultimate goal is to densify the product and ensure that the inside and outside have the same degree of densification. The existing cold isostatic pressing method cannot measure the shrinkage of the product in the press and the volume density of the formed product, and can only set the pressure holding time based on experience. The longer the pressure holding time, the higher the volume density, and the shorter the pressure holding time, the lower the volume density. However, the true volume density can only be calculated after the product is demolded after forming.

[0006] Too long pressure holding time is not helpful for improving the volume density of the product, but affects the production efficiency, accelerates the stress fatigue of the cold isostatic press body and reduces the service life of the press. UTILITY MODEL CONTENTS

[0007] The utility model aims to provide an isostatic pressing green body volume shrinkage control device, which solves the above problems by using the device.

[0008] In order to solve the above technical problems, the utility model provides technical scheme as follows: a kind of isostatic pressing green body volume shrinkage control device, including cold isostatic pressing machine cylinder and mould barrel, mould barrel is arranged in the inside of cold isostatic pressing machine cylinder, the top of cold isostatic pressing machine end cover is provided with overflow device on the right side of cold isostatic pressing machine end cover top, pressure measuring device is arranged at the top of cold isostatic pressing machine cylinder right side wall, the bottom of cold isostatic pressing machine cylinder right side wall is provided with pressurizing device with flowmeter and pressure relief device with flowmeter, pressurizing device with flowmeter is located above pressure relief device with flowmeter, PLC control cabinet is provided on the right side of cold isostatic pressing machine cylinder.

[0009] Preferably, the inside of the mould barrel is sleeved with a sealing rubber sleeve, the inside of the sealing rubber sleeve is provided with a shaped product, and the inside of the cold isostatic pressing machine cylinder is filled with an emulsion.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] 1. The isostatic pressing green body volume shrinkage control device provided by the utility model has two flowmeters, and the flow of emulsion can be measured during pressurization and pressure relief, and the PLC system calculates the volume shrinkage of the shaped product according to the flow of emulsion entering the press cylinder. During pressurization, the pressure relief valve is in a closed state, and the flowmeter can be used to detect the leakage of the pressure relief device. During pressure maintenance, the valve of the pressurizing device is in a closed state, and the flowmeter can be used to detect the leakage of the pressurizing device.

[0012] 2. The isostatic pressing green body volume shrinkage control device provided by the utility model, the PLC system can automatically calculate the flow of emulsion remaining in the cylinder according to the flow difference between the pressurizing device and the pressure relief device, so as to calculate the volume shrinkage of the shaped product. According to the loading weight of the shaped product and the volume shrinkage during the shaping process, the volume density increase of the shaped product is automatically calculated. According to the initial volume and weight of the shaped product loaded in the sealing rubber sleeve, the initial volume density of the shaped product is automatically calculated, and the real-time volume density of the shaped product during the shaping process is automatically calculated according to the volume density increase during the shaping process. The PLC system determines the appropriate pressure maintenance time according to the volume density change.

[0013] 3. The isostatic pressing green body volume shrinkage control device, different forming products, the powder particle size, etc. are different, the finer the powder, the greater the shrinkage, the longer the pressure holding time required, the larger the specification, the greater the shrinkage, and the longer the pressure holding time required. The conventional operation is to fix the pressure holding time, usually 20-30 min. For small size or coarse particle size products, this pressure holding time may be too long, affecting production efficiency and press service life, or too short to cause insufficient compaction of the formed product. The PLC system can automatically calculate the shrinkage of the formed product according to the emulsion flow, select the appropriate pressure holding time, ensure that the volume density of the formed product meets the forming requirements, and shorten the invalid pressure holding time, improve the production efficiency and the service life of the press. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a front view structural schematic diagram of the utility model.

[0015] The reference signs in the drawing are explained: 1, cold isostatic press cylinder; 2, emulsion; 3, die barrel; 4, sealing rubber sleeve; 5, formed product; 6, cold isostatic press end cover; 7, overflow device; 8, pressure measuring device; 9, pressure device with flowmeter; 10, pressure relief device with flowmeter; 11, PLC control cabinet. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

[0017] In order to further understand the content of the utility model, the utility model will be described in detail in combination with the drawings.

[0018] In combination with Figure 1 As shown in the utility model, an isostatic pressing green body volume shrinkage control device comprises a cold isostatic press cylinder 1 and a die barrel 3, the inside of the cold isostatic press cylinder 1 is provided with the die barrel 3, the top of the cold isostatic press cylinder 1 is provided with a cold isostatic press end cover 6, the right side of the top of the cold isostatic press end cover 6 is provided with an overflow device 7, the top end of the right side wall of the cold isostatic press cylinder 1 is provided with a pressure measuring device 8, the bottom end of the right side wall of the cold isostatic press cylinder 1 is provided with a pressure device with flowmeter 9 and a pressure relief device with flowmeter 10, the pressure device with flowmeter 9 is located above the pressure relief device with flowmeter 10, and the right side of the cold isostatic press cylinder 1 is provided with a PLC control cabinet 11.

[0019] The inside of the mold barrel 3 is sleeved with a sealing rubber sleeve 4, the inside of the sealing rubber sleeve 4 is provided with a shaped product 5, and the inside of the cold isostatic pressing machine cylinder body 1 is filled with an emulsion 2.

[0020] Specifically, the sealing rubber sleeve 4 is sleeved in the mold barrel 3, the sealing rubber sleeve 4 is tightly attached to the inner wall of the mold barrel 3, and the shaped product 5 is usually a powder. A certain amount of powder is loaded into the sealing rubber sleeve 4 for vacuumizing and the like, so that the shaped product 5 is isolated from the outside.

[0021] The mold barrel 3 is hoisted into the cold isostatic pressing machine cylinder body 1 together with the sealing rubber sleeve 4 and the shaped product 5, the emulsion 2 is injected into the cylinder body to fill the entire cavity, and the mold barrel 3 and the sealing rubber sleeve 4 are completely immersed in the emulsion 2.

[0022] The press is controlled to cover the cold isostatic pressing machine end cover 6, so that a closed cavity is formed in the cold isostatic pressing machine cylinder body 1. The pressuring device 9 with a flowmeter is controlled to supplement the emulsion 2 in the cylinder body until the overflow device 7 automatically blocks after discharging the remaining air in the cylinder body.

[0023] The pressuring device 9 with a flowmeter continues to supplement the emulsion 2 in the cylinder body under the control of the PLC system. Since the liquid is incompressible, the cold isostatic pressing machine continuously increases the pressure under the action of the continuously supplemented emulsion 2, and at the same time, the shaped product 5 in the sealing rubber sleeve 4 shrinks. When the pressure reaches the set value, the pressuring device closes the valve to stop pressurizing, and the shaped product 5 continues to shrink under high pressure in the cylinder. Since the product shrinks and the volume becomes smaller, the pressure in the cylinder decreases. When the decrease value reaches the set pressure value, the pressuring device is controlled by the PLC system to supplement the pressure until the set pressure is reached again.

[0024] The flowmeter records the flow of the emulsion 2 throughout the pressurizing and pressure supplementing process. The PLC system calculates the volume shrinkage of the shaped product 5 according to the flow of the emulsion 2, and calculates the bulk density of the shaped product 5 according to the input initial volume of the sealing rubber sleeve 4 and the weight of the shaped product 5. When the calculated bulk density reaches the set value, the pressure holding is completed, the pressure relief device 10 with a flowmeter is automatically opened for pressure relief until normal pressure. Then the cold isostatic pressing machine end cover 6 is lifted, the mold barrel 3 is hoisted out, the sealing rubber sleeve 4 and the shaped product 5 are taken out of the mold barrel 3, and the shaped product 5 is weighed, measured in size, inspected in quality, and calculated in bulk density. According to the final calculated bulk density of the shaped product 5, each parameter in the PLC control system is revised, thereby improving the accuracy of system operation.

[0025] It is to be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0026] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made therein without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A device for controlling the volume shrinkage of green blanks formed by isostatic pressing, comprising a cold isostatic press cylinder (1) and a mold barrel (3), characterized in that: The inside of the cold isostatic press cylinder (1) is provided with a mold barrel (3), the top of the cold isostatic press cylinder (1) is provided with a cold isostatic press end cover (6), the right side of the top of the cold isostatic press end cover (6) is provided with an overflow device (7), the top of the right side wall of the cold isostatic press cylinder (1) is provided with a pressure measuring device (8), the bottom of the right side wall of the cold isostatic press cylinder (1) is provided with a pressurizing device (9) with a flow meter and a pressure relief device (10) with a flow meter, the pressurizing device (9) with a flow meter is located above the pressure relief device (10) with a flow meter, and a PLC control cabinet (11) is provided on the right side of the cold isostatic press cylinder (1).

2. The isostatic pressing green body volume shrinkage control device according to claim 1, characterized in that: The mold barrel (3) is fitted with a sealing sleeve (4), and the molded product (5) is placed inside the sealing sleeve (4). The interior of the cold isostatic press cylinder (1) is filled with emulsion (2).

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