1·The slide adopts hydraulic overload protecting device, which controlled imported pump valve;
滑块采用液压过载保护装置，进口泵阀控制；
2·The utility model provides a double-stage slide valve vacuum pump, which consists of an air pipe and two slide valve cylinders.
一种双级滑阀真空泵，由气路管道和二级滑阀缸组成。