Evaporator, and control method for vacuum degree, evaporation kettle liquid level and water tank water level detection

Abstract

The invention relates to an evaporator, and a control method for vacuum degree, evaporation kettle liquid level and water tank water level detection. The method comprises: starting a system; detectingthe liquid level of a waste liquid barrel; determining whether the liquid level is low or not, if yes, controlling, by a PLC, a circulating water pump to be closed and turning on an emptying valve, and otherwise, controlling, by the PLC, the circulating water pump to start, and turning on a liquid inlet valve so that the circulating water pump runs to turn the pressure in an evaporation kettle tobe negative pressure; determining whether the vacuum degree is larger than a set value or not, if yes, starting a compressor so that a refrigerant starts to circulate, and otherwise, returning; sucking a stock solution into the evaporation kettle through the liquid inlet valve under negative pressure, and detecting the liquid level of the evaporation kettle by a sensor; if the liquid level is higher than the high liquid level, controlling the liquid inlet valve to be turned off by the PLC in the evaporation kettle; if the liquid level is lower than a low liquid level, determining whether thenumber of times of liquid supplementing is larger than a set value or not by the PLC, if not, controlling the liquid inlet valve to be turned on by the PLC and returning, and if yes, controlling the emptying valve and the liquid discharging valve to be turned on by the PLC, starting a liquid discharging pump, turning off the compressor and the circulating water pump, after concentrate is discharged after set time, turning off the emptying valve, the liquid discharging valve and the liquid discharging pump and returning.

Description

technical field [0001] The invention relates to the technical field of waste liquid treatment, in particular to a control method for detecting the vacuum degree of an evaporator, a vacuum gauge, detecting the liquid level of an evaporating kettle, and detecting the water level in a water tank. Background technique [0002] PCB, electroplating and other industries will produce waste liquid in the production process. The main pollutants are COD, nitrogen, phosphorus and heavy metals. If discharged without treatment, it will seriously pollute the environment and endanger human health. Waste liquid has the characteristics of many types of pollutants, high concentration, small amount and dispersed distribution. Common treatment methods include chemical method, membrane separation method and evaporation method. At present, most enterprises outsource the disposal of waste liquid, and there are problems such as high disposal costs, untimely transshipment, and backlog storage that a...

AI Technical Summary

Problems solved by technology

Another technical problem solved by the present invention is to provide a control method for PLC automatic control of water level detection in the circulating water tank

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