In recent years, there has been an increasing use of miniaturized pneumatic systems for a wide variety of applications. Many of these systems employ readily available miniature cylinders of pressurized gas, such as carbon dioxide, as their source of gas to operate the various system elements. Although the use of small cylinders of compressed gas allows the construction of extremely compact pneumatic systems, such systems are often limited by the relatively small supply of gas contained in these cylinders. The problems associated with the limited supply of gas are exacerbated by the use of inefficient switching valves designed for use on larger pneumatic systems in which the supply of gas is not a serious constraint.
Another consideration in the design of a portable pneumatic switching system is the ability to control the operation of the switch function electronically. Electrically controlled pneumatic systems typically employ a system of solenoid controlled valves which require a constant supply of current to maintain the valve in the desired position. Again, this is not a major concern in larger systems which have readily available sources of power. However, it is a significant constraint in the design of portable systems which will operate the solenoids with batteries.