What is the working principle of steam trap?

Steam trap is installed between the steam heating equipment and water back into the manifold. When driving, barrel at the bottom, the valve fully open. After the water into the steam trap flow to the bottom, full body, completely submerged barrel, and then, the condensate to the manifold back by a fully open valve. The steam from the bottom of the barrel into the trap, also occupy the top of the barrel body, create buoyancy. Barrel rises slowly and gradually to the seat direction lever, until completely close the valve. Air and carbon dioxide gas vent holes through the barrel, gathered at the top of the trap. From vent discharge of steam, condensation due to trap the heat. When in the condensate began full barrel barrel to leverage to create a pull. As condensation water level rising, the force of increasing, until can overcome the pressure difference, open the valve. Steam trap valve began to open, the differential pressure acting on the disc will be reduced. Barrel will fell rapidly, make the valve fully open. Accumulate at the top of the trap no non-condensable gas discharge first, and then discharge frozen water. When the water flow from barrel sewage flow trap together. Condensate emissions at the same time, steam to enter the trap, and a new cycle begins.