Proportional Solenoids provide a specific stroke position that is controlled by the input current. The stroke can be varied in direct proportion to the input current. These are mostly used for pressure control valves. These are analog device, allowing for incremental positioning. This feature is made possible by a unique design of the magnetic pole configurations. Thus the position of the armature is controlled by varying the input current to the coil. The more current that is applied to the coil, the further the armature moves in its stroke. This provides stable output force characteristics with low hysteresis and a fast response time for a wide variety of applications, especially for hydraulic applications.

Proportional Valve is an economical proportional valve for use with gases. It combines a solenoid valve with an electronics package, which digitally modulates the control signal to provide analog proportional control without the expense or complexity of stepper motors, servo valves or other proportioning devices. It can be used in open or closed loop systems to control flow, pressure, temperature, speed or position parameters of gases. There are two types of proportional valves force controlled and stroke controlled. With a force controlled proportional valve, a provision is provided to increase the force output by the solenoid proportional to the input signal. Both types provide an opening of the valve proportional to the magnitude of the milliamp current applied to the valve. Spool movement is proportional to the input current.

Proppants are spherical ceramic beads, about the size of a grain of sand, that are fired at a high temperature and are able to maintain their integrity under immense pressure. It is inserted into hydraulically created underground fractures surrounding oil and gas wells to prop open fractures and increase the productivity of the wells.