Liquid ring vacuum pump negative pressure system
This paper introduces a negative pressure system based on liquid ring vacuum pump, which is mainly used for filling liquid materials, and puts forward a solution for heating and negative pressure regulation of liquid ring vacuum pump in the process of system operation. The system has been applied in the actual production, running reliably and stably, providing a new idea for the design of the negative pressure system.
Liquid ring vacuum pump as a crude vacuum pump, with its compact structure, small footprint, gas isothermal compression, without lubrication and other characteristics, and widely used in machinery, pharmaceutical, food, petrochemical and other fields. The negative pressure system designed in this paper is applied to the filling of a special material in the chemical industry. The 2BV series liquid ring vacuum pump is used as the main body to pump corrosive gas, and the heating of the vacuum pump and the adjustment of the negative pressure value of the system are successfully solved during the operation of the system. At present, the negative pressure system has been put into actual production and runs reliably and stably.
1. Structure and working principle of the negative pressure system
The negative pressure system is mainly used to pump the excess materials into the fixed container during the filling process of special materials with corrosion and volatilization, and recover the gas extracted from the vacuum pump into the corresponding container. Because of the special physical property of this material, the negative pressure system is required to be in the working state all the time in the production process, and the liquid ring vacuum pump is also required to be in the normal working state, to maintain the negative pressure stability of the whole system.
1.1 composition of the negative pressure system
The system is mainly composed of liquid ring vacuum pump, gas-water separator, circulating tank, anti-corrosion vacuum one-way valve, pneumatic ball valve, negative pressure sensor, dial type vacuum pressure gauge, excess material temporary storage equipment, manual negative pressure control valve, level gauge, temperature sensor, filter, related pipeline and so on. The level gauge and temperature sensor monitor the circulating water level and temperature in the gas-water separator during the production process. Before production, the water at the specified liquid level is injected into the excess material temporary storage equipment through the program control, and the sensor is also set to monitor the temperature and liquid level. At the same time, the negative pressure sensor and the dial vacuum pressure gauge are set to check the negative pressure value of the system in the production process. In the production process, the manual negative pressure regulator can be adjusted according to the need to adjust the system negative pressure value, which is also the focus of this paper.
1.2 working process of the negative pressure system
1) firstly adjust the negative pressure value of the negative pressure system. Open the liquid ring vacuum pump, check the values of dial vacuum pressure gauge, negative pressure sensor 2 and negative pressure sensor 1, and confirm that the negative pressure value in the excess material storage equipment reaches a stable level, and then compare with the vacuum value required in the production process, so as to adjust the negative pressure control valve to make the vacuum degree meet the production requirements.
2) material filling. When the liquid material reaches the set value of the system, the excess liquid material enters the temporary storage equipment through the negative pressure system pipeline. At the same time, the relevant valve at the entrance of the material is closed to stop the material injection.
3) after the material inlet stops the material injection, the valve connecting the negative pressure pipeline and the material inlet pipeline is opened, and the material is injected into the main pipeline and inhaled into the excess material temporary storage equipment; When the negative pressure value of negative pressure sensor 1 is stable, close the bypass suction valve.
2. Design of negative pressure system
The negative pressure system proposed in this paper is designed for special liquid materials. Based on the filling method of materials and its special physical properties, the loop of negative pressure pump exhaust gas recovery to the filling equipment is added in the system. This paper mainly introduces the negative pressure regulation of the system and the circulating water temperature drop loop of the liquid ring vacuum pump.
2.1 negative pressure regulation circuit
The negative pressure regulating valve is located on one of the air outlet of the gas-water separator, and the negative pressure in the main road can be adjusted by adjusting the gas flow back into the vacuum pump.
At present, the negative pressure system has been put into production and runs reliably and stably. The water circulation system of liquid ring vacuum pump completely solves the problem of negative pressure drop caused by pump body heating, and the negative pressure regulation range is relatively large, providing a better solution for the design of negative pressure system based on liquid ring negative pressure pump.