Slit valve apparatus

A slit valve apparatus comprising:

• a door plate configured to open and close an opening of a valve housing;
• a valve rod connected to the door plate;
• a guide housing disposed at a lower end of the door plate and disposed so that the valve rod passes therethrough;
• an L-motion block disposed in an internal space of the guide housing and connected to the valve rod;
• a cam block connected to the L-motion block and disposed in the internal space of the guide housing;
• a driving rod connected to a lower end of the valve rod;
• and
• a driving unit connected to the driving rod to drive the driving rod,
• wherein the driving unit includes a cylinder having an internal space and a piston driven up and down in the internal space of the cylinder,
• wherein the cylinder includes an inlet through which air flows, an outlet spaced apart from the inlet, and a piston movement recess disposed between the inlet and the outlet and configured to allow the piston to move therein, and
• wherein the cylinder includes a first orifice connecting the inlet to the piston movement recess and a second orifice connecting the outlet to the piston movement recess.