one of the main elements in pneumatic automation; consists of a cavity filled with air or another gas.
A distinction is made between constant (nonadjustable) and variable (adjustable and controlled) pneumatic capacitances. The volume of a constant pneumatic capacitance is usually bounded by rigid walls and remains virtually unchanged during operation. The volume of a variable pneumatic capacitance can be changed substantially by manual, automatic, or remote external action. To improve the dynamics of pneumatic equipment, the pneumatic capacitances that have no functional purpose (called spurious capacitances) should be reduced as much as possible.