Vacuum stop valve

The utility model relates to the technical field of vacuum stop valves, in particular to a vacuum stop valve which comprises a tee joint, flange plates are fixedly installed at the two ends of the tee joint respectively, an installation frame is fixedly installed at the upper end of the tee joint, a lead screw is arranged in the installation frame in a threaded and penetrating mode, and a hand wheel is fixedly installed at the upper end of the lead screw. And a replacing device is arranged on the surface of the flange plate. According to the utility model, by arranging the replacing device, the sealing gasket can be replaced by screwing the two nuts on the flange plate and loosening the two nuts, so that the phenomenon that the sealing gasket can be replaced only by completely disassembling the flange plate between the valve body and the pipeline is avoided; and then, the flange plate and the pipeline need to be positioned and mounted again, so that the sealing gasket can be replaced, the workload of workers