Pipeline leakage monitoring and negative pressure protecting device

The utility model relates to a pipeline leakage monitoring and negative pressure protecting device, which comprises a monitoring device and a negative pressure protecting device, wherein the monitoring device comprises a first pressure transmitter and a second pressure transmitter; a first PLC (programmable logic controller) data acquisition device is electrically connected with the first pressure transmitter; the second pressure transmitter is electrically connected with a second PLC data acquisition device; a control circuit is electrically connected with the first PLC data acquisition device and the second PLC data acquisition device, receives signals of the first PLC data acquisition device and the second PLC data acquisition device, and analyzes and processes to control the work of the negative pressure protecting device; when leakage occurs, the pressure of a leakage part is reduced caused by differential pressure inside and outside a pipeline, liquid around the leakage part supplements the leakage part, negative pressure fluctuation is generated in the pipeline, so that pressure sensors at the two ends of the pipeline receive instantaneous pressure information of the pipeline to judge the occurrence of the leakage as the negative pressure is spread upstream and downstream from a leak source; and the pipeline leakage monitoring and negative pressure protecting device is sensitive to a sudden leakage, can detect the leakage within 3 minutes and has high sensitivity.