Abstract
The pressure level of pneumatic devices is not only above atmospheric pressure but also below atmospheric. In particular, devices operating at low pressure and middle pressure vacuums are essential. However, vacuum pressure systems are not energy saving because of their low energy efficiency.
This study proposes a new type of positive and negative pressure source with an unload circuit. This new pump could generate positive pressure from the exhaust side and vacuum pressure from the intake side. However, if it generates both pressures simultaneously, the load of the pump increases. This circuit is equipped with an unload mechanism that can control the level of the positive and vacuum pressures by control valves. As a result, the energy consumption at low level when pressure is produced using this system is smaller than that using the usual two pumps separately. The proposed system has advantages in energy efficiency and space availability.
