Trapped piston ring

The liquid-ring or liquid-piston compressor is shown in Figure 36.8. It has a rotor with multiple forward-turned blades that rotate about a central cone that contains inlet and discharge ports. Liquid is trapped between adjacent blades, which drive the liquid around the inside of an elliptical casing. As the rotor turns, the liquid face moves in and out of this space due to the casing shape, creating a liquid piston. Porting in the central cone is built-in and fixed and there are no valves. 

Air which is compressed in a conventional ringed piston compressor will contain particles of oil and dirt and, when it cools, droplets of water. The bulk of these contaminants will be removed by traps, filters, dirt eliminators, air receivers, and by an aftercooler, if fitted. The resultant air is then clean enough for most applications. The air feed to air motors, which require lubricating, is passed through air lubricators. It is important for the operator to check that the transparent bowl of the air filter is clear and that the air lubricator is filled to the required oil level before using machines which have these fitted in the air supply line. 

The liquid-ring, or liquid-piston, compressor is shown in Figure 8.8. It has a rotor with multiple forward-turned blades that rotate about a central cone that contains inlet and discharge ports. Liquid is trapped between adjacent... 

The samples for PALS experiments were prepared in the sandwich configuration (sample-positron source-sample). During the preparation it was formed into pastille (mechanically pressed to about 50 MPa) and placed in the argon pressure chamber. The other part of the same sample was mechanically compressed. The MCM-41 sample was put into a small tube, closed by two movable pistons sealed by 0-rings. The air from the container was evacuated to the pressure of about 0.5 Pa. Such a set was placed in the argon pressure chamber, so that mechanical pressure exerted by the pistons pushed by argon could be applied to the sample. The PALS spectra were collected in both cases in the pressure range 0.1-490 MPa. The positronium annihilation method for characterization of porosity of solids is based on the relation between ortho-positronium (o-Ps) lifetime and the size of free volume, in which o-Ps is trapped. The PALS spectra were processed as described in Ref. [9]. 

Positive displacement compressor uses mechanical components to trap gas and then compress it to hi er pressure. Positive displacement compressor can be further classified into reciprocating compressor and rotary compressor. Reciprocating compressor uses reciprocating motion of piston, plunger, or diaphragm in a cylinder or head to compress gas. Rotary compressor uses continuous rotating screws, lobes, vanes, or liquid ring to compress gas. 

---