Axial Pressure Release Double Media Cold Isostatic Press
Cold isostatic press has undergone a spiral process of development from one with single medium to one with double media and again from one with double media to one with single medium, indicating a technological progress and rise, facilitating further perfection of the equipment to meet the need of the user. A brief development process has been described as follows:
I. Single medium (water or emulsion) cold isostatic press (Drawing 1)
Principle and structure: Pressurization and pressure release are realized with the help of water medium. The big piston of the intensifier drives the emulsion (or oil) to the main cylinder from the cavity after pressurization to facilitate formation of the work piece.
Advantage: 1. The nominal or effective cylinder stem may help effective utilization of the space in the main cylinder.
Shortcomings: 1. The ultra high-pressure water containing impurities may damage the mouth of the valve during pressure release, often resulting in the problems of slow or non-pressure increase followed by frequent repairing.
2. Fast injection of liquid during low pressure cannot be accomplished with water supply by double medium intensifier while 80% of the task for formation of work piece needs to be completed during low pressure, thus prolonging the time for formation of the work piece.
3. With the adoption of double medium intensifier, the ultra high-pressure water may be mixed with oil easily.
II. Radial isolation double medium cold isostatic press (Drawing 2)
Principle and structure: Put a rubber sleeve in the main cylinder to separate the oil out of the bucket and water in the bucket. The intensifier may inject the ultra high pressure oil to the outside of the separating sleeve and realize formation of the work piece by pressing the water with the rubber sleeve.
Advantages: 1. The sleeve separates oil and water. Water containing impurities is kept in the sleeve. The oil out of the sleeve will not damage the valve during pressure release, resulting in long working hours of the equipment.
2. Fast pressurization of oil may be achieved during low pressure, saving time for formation of work piece, which is about 30%¡«60% comparing with the time for formation of work piece by single medium equipment.
Shortcomings: 1. Effective volume for pressurization is reduced 40%¡«50% with the addition of the separating sleeve.
2. Any inadequate calculation of the pressing capacity or placement of the work piece etc may enable the sleeve to press onto the work piece to result in breakage and pollution of the entire oil system.
3. Incident relating to the mixing of water in the rubber sleeve and oil out of it is unavoidable.
4. Ineffective liquid will increase to cause higher consumption of energy, which is above 30%.
III. Radial Isolation single medium pressurization and double medium pressure release cold isostatic press (Drawing 3)
Principle and structure: A bowl type rubber cover or a 2-direction equal pressure sealing board is laid above the bottom of the main cylinder. Prior to pressurization, oil or water pump of low pressure and small volume pushed up their rise to fill in the cavity while the double medium intensifier will motivate the ultra high pressure water to run through the bottom of the cylinder by the oil cavity into the upper part of the water cavity to press the work piece. After completion of pressurization, there will be a release of oil followed by the falling of the separating board or the bowl type cover, the pressure of the main cylinder down to zero, return of the lid and bottom of the cylinder, coming out of the frame and uncovering of the cylinder.
Advantages:? 1. Nominal cylinder stem is the effective cylinder stem, without waste of volume or energy.
2. Pressurization is realized with the help of water and pressure release by oil (or water), ensuring long normal operation of the pressure release valve.
3. Pollution of the system owing to breakage of the separator is completely avoided.
4. Oil (or water) used for pressure release is less, hence the smaller volume of the oil (water) tank for pleasure release. In addition, the volume of pressurization of the main cylinder is not big either.
Shortcomings:? 1. Fast pressurization is not possible.
2. Double medium intensifier may cause mixing of oil and water.
TPY has conducted the following technical innovations on the basis of the available patent so as to overcome the existing shortcomings described in above article III.
- Adoption of hydraulic intensifier system featured by fast and pre-pressurization (patent).
- Adoption of double medium intensifier, eliminating the problem relating to mixture of oil and water.
The cold isostatic press of a new type manufactured by TPY has already come into emergence, starting its normal operation in some factories. It has shown more advantageous economic and technical features comparing with the previous double medium cold isostatic press used the rubber cover for separation purpose, indicating a fresh contribution to the technological development of cold isostatic press.
Pressurization with ultra high-pressure water Release of high-pressure water
Drawing 1. Single medium structure:
Pressurization with ultra high-pressure oil release of ultra high-pressure oil. Drawing 2. Vertical separator double medium structure:
Pressurization by ultra high-pressure water release of ultra high-pressure oil.
Drawing 3. Axial separator double medium pressure release structure:
