Low temperature wax high-pressure dewaxing kettle is a key equipment used in the precision casting industry to remove low-temperature wax molds. It uses high-pressure steam environment to quickly melt wax molds and recover wax materials. Here is a detailed introduction about it:
1、 Structural composition
Kettle body: composed of inner liner, wax collection tank, outer liner, wax conveying pipeline, steam conveying pipeline, drainage pipeline, etc. The inner liner material is generally 304 stainless steel, used to place the mold shell for dewaxing; The external gallbladder is a steam generator, often made of high-quality carbon structural steel, which generates high-temperature and high-pressure water vapor through electric heating. Double layer insulation material is filled between the inner and outer bile ducts to reduce heat loss.
Kettle door mechanism: usually adopts a mechanical quick opening door structure, with smooth and safe opening and closing. The kettle door is equipped with a safety interlock mechanism. When the pressure inside the kettle has not returned to zero, external force cannot open the kettle door; When the door is not closed properly, steam cannot enter the inner chamber chamber.
Heating system: The outer chamber serves as a steam generator, heating water to generate high-pressure steam through electric heating elements, providing the required heat and pressure for the dewaxing process.
Control system: It has two modes: manual control and automatic control. Automatic control generally adopts PLC, which can automatically complete the entire dewaxing process with one click after inputting process parameters. It also has safety automatic detection function, which can meet all the action control and interlocking requirements of the equipment, and has complete safety protection functions such as overload, overvoltage, overcurrent, short circuit, and phase loss.
Automatic water replenishment device: mainly composed of water pump, water storage tank, liquid level control system, etc., it can ensure that heating and automatic water supply are stopped when the water level reaches the lower limit, prevent accidents caused by dry burning of the heater, and stop water supply when the water level reaches the upper limit.
Wax collection system: The bottom of the kettle is equipped with a wax discharge valve. The melted wax during dewaxing flows into the collection device below through the wax discharge valve. The collection device usually has a filter screen that can filter out impurities in the wax.
2、 Working principle
The working principle of the low-temperature wax high-pressure dewaxing kettle is to use the heat of high-pressure steam to quickly melt and vaporize the low-temperature wax mold, thereby removing the wax from the mold shell. The specific process is to place the shell coated with low-temperature wax mold into the inner pot of the dewaxing kettle, close the kettle door and lock it. The water in the outer bladder is heated by an electric heating element to generate high-pressure steam, which enters the inner bladder through a steam pipe and rapidly increases the pressure and temperature inside the inner bladder. In high temperature and high pressure environments, low-temperature wax molds quickly melt and vaporize. Liquid wax flows into the wax collection device through the wax discharge pipeline, while gaseous wax condenses into liquid wax after cooling and is collected. After dewaxing is completed, release the pressure inside the inner container first, and then open the kettle door to remove the shell.
3、 Main technical parameters
Design pressure: Common pressures include 1.0MPa (10bar), 1.3MPa (13bar), etc.
Work pressure: generally between 0.6-0.9MPa (6-9bar).
Design temperature: usually 180 ℃ -192 ℃.
Working temperature: ≤ 179 ℃.
Pressure balance time: usually 3-5 seconds, can quickly achieve pressure balance between the inner and outer bile ducts.
Dewaxing cycle time: adjustable from 0-60 minutes, can be set according to different dewaxing process requirements.