A vacuum buffer tank is also called a negative – pressure buffer tank. It can be made of stainless steel or carbon steel. A vacuum buffer tank made of stainless steel is simply called a stainless – steel vacuum tank. The function of a vacuum buffer tank is to buffer the pressure fluctuations of the system, make the system work more stably, prevent the backflow of materials, and can also be used for gas – liquid separation to achieve a stable vacuum degree (otherwise, the vacuum degree cannot meet the requirements). Most vacuum buffer tanks have a vertical structure. Those used in the food and pharmaceutical industries are generally made of stainless steel. The air inlet is generally set on the side, and the feeding is carried out in a tangential direction, which is conducive to gas – liquid separation. The air extraction port is at the upper part of the tank. The liquid is discharged from the lower part. A pressure vacuum gauge port, an air inlet, an exhaust port, a liquid discharge port, etc. are set on the tank. A one – way valve is set on the pipeline to prevent the back – suction or backflow of liquid. The vacuum buffer tank is placed in front of the vacuum pump, that is, at the inlet direction of the vacuum pump.
The function of a compressed – air buffer tank is similar to that of a vacuum buffer tank. Its function is to reduce the pressure fluctuations of the air system, ensure the stable and continuous air supply of the system. A compressed – air buffer tank is usually set at the outlet of the air compressor and at the gas – using point. The air buffer tank set at the outlet of the air compressor is mainly to reduce the pulsation of the outlet pressure of the air compressor and separate the water in the compressed air. For a reciprocating compressor, the volume of the air buffer tank at the outlet of the air compressor is generally about 10% of the air compressor’s flow per minute (Nm3/min). For a centrifugal or screw – type centrifuge, since the air pressure at its exhaust port is relatively stable, the main function of the air buffer tank is to separate the condensed water, and its size and volume are determined according to the requirements of separating the condensed water; while the air buffer tank set at the gas – using point functions to adjust the gas – using load, reduce the system pressure fluctuations caused by the change of gas consumption at different gas – using points, and ensure the normal operation of the production device. The structure of a compressed – air buffer tank is similar to that of a vacuum buffer tank. Their structures are relatively simple, and the main thing is to determine the volume.
