往复式压缩机原理介绍.ppt

By now you should understand how a compressor works and what most of the major components are. Let us now look at what happens to the gas before it gets to the cylinder and after it leaves the cylinder. We will do this by viewing a standard process gas flow schematic. This should familiarize us with the remainder of the major components that make up a gas compressor package. The gas first passes through a suction strainer commonly referred to as a witches hat. This strainer is a combination of wire mesh and a steel cone. It should be cleaned when the differential pressure across it becomes excessive or the compressor may be starved of inlet gas which could lead to valve failure and temperature problems. The gas then passes through an inlet separator called a scrubber. Its purpose is to further extract any debris that may have passed through the inlet strainer and primarily to separate out any liquids. The scrubber has many components that work together to separate and dispose of the liquid. The gas first enters the scrubber and comes in contact with a baffle which causes turbulence in the gas flow. This turbulent action separates out the heavy liquid which quickly drops to the bottom of the scrubber and starts accumulating. A sight glass allows an operator to monitor the level of the liquid collecting in the scrubber. The light mists of liquid try to follow the gas out of the scrubber but first must pass through a mist extractor. The mist coalesces on this mesh pad until it becomes heavy enough to drop to the bottom of the scrubber. When the liquid level starts to rise to a critical level, the float on the level controller rises, causing the pneumatic valve in the controller to open. When this valve opens, a pneumatic signal passes to the automatic dump valve causing it to open. Once the valve is open, the pressure in the scrubber pushes the liquid out and it is then directed to a safe location. Once the liquid falls enough to lower the float on the co