What is vacuum negative pressure system
Vacuum negative pressure unit is necessary equipment for lost foam casting technology. The technical personnel of the EVP vacuum manufacturer combined with domestic and foreign related technologies and actual production experience and characteristics, a new generation of vacuum negative pressure device after years of development and research, is the core equipment in the production of lost foam casting, mainly used in pouring Process requirements in the process.
1、 Structure and use
The vacuum system mainly consists of vacuum pump, tail gas treatment tank, buffer tank, negative pressure gauge, connecting pipe, water bath tank, drain pipe, ball valve, water inlet pipe, water inlet pipe of vacuum pump, vacuum distributor, etc.
The vacuum distributor connects the negative pressure sand box through the high temperature rubber hose to make the molding sand in the sand box compact, so as to complete the liquid casting under the current stable negative pressure field.
According to the actual scale of users, we have developed four specifications of negative pressure system. This equipment covers a small area and is easy to install. At the same time, it has the functions of voltage stabilization, air filtration, dust removal, vacuum point distribution, etc.
2、water ring vacuum pump working principle
The air and other gases in the negative pressure sand box are pumped by the water ring vacuum pump to compact the sand in the sand box, so as to complete the liquid pouring under the stable negative pressure field. The extracted gas enters the water bath tank first, and then the gas, dust and impurities that can be adsorbed by water are removed in the water bath tank, and then enters the buffer tank, where the gas pressure can be buffered to obtain a relatively stable air flow. After entering the tail gas treatment tank by water ring vacuum pump, the gas is further purified in the tail gas treatment tank and then discharged into the atmosphere. The adsorbed impurities and gases are discharged from the tank through the exhaust pipe and ball valve under the action of circulating water.
4、 Installation of equipment
water ring vacuum pump installation
Installation of water ring vacuum pump: before the installation of vacuum pump, rotate the coupling by hand to ensure that there is no jamming and other damage in the pump. When the whole set of equipment arrives at the installation site, if the package has been damaged or damped, and the pump has been delivered for more than eight months, it shall be completely disassembled and inspected before installation. After inspection, it shall be placed on the preset foundation smoothly and firmly fixed with foundation bolts.
The motor and pump shaft, even if there is a slight inclination, will cause serious consequences such as bearing heating and premature wear of parts. If the installation is correct, the pump shaft can be easily turned after use. Filter device shall be installed at the air inlet of the pump to prevent foreign matters from entering the pump cavity.
If the tail gas treatment tank, buffer tank and water bath tank are installed on the foundation according to the outline drawing, if the installation position must be changed, it should be noted that the connecting pipeline should not be too long and the turning should not be too fast, otherwise the flow loss of water and gas in the pipeline will increase, thus increasing the pressure at the exhaust end of the pump, thus reducing the air volume and vacuum degree, and increasing the power consumption. The pipeline with valve 10 pumps are connected with tail gas treatment tank, which can make working fluid recycled. A water supply pipeline is installed on the tail gas treatment tank, and the water supply quantity is regulated by the valve.
A valve is installed on the vacuum distributor pipeline for control, so as to prevent the working fluid in the pump from flowing back to the system due to the vacuum suction of the system when stopping.
5. Regulatory structure
The water ring vacuum pump adjusts the vacuum degree and air volume through the valve installed on the intake pipe and the vacuum distributor pipe. The vacuum degree can be adjusted according to the vacuum degree regulating valve required by negative pressure sand box casting.