Impulse valve for remote control of hydraulic systems.

A pulse valve is a standard directional control valve that has been extended with a mechanical actuator. This pneumatically or electromagnetically operated actuator switches the valve by means of a pulse.

Structure of Pulse Valves

Pulse valves ensure remote-controlled and automated operation of actuators in hydraulic and pneumatic systems. This makes these systems convenient and safe to use. The controlling component is a standard switching valve, such as a 4/2-way valve. The control spool is connected to a pneumatically or electromagnetically operated piston. A short stroke of the piston, the eponymous pulse, causes the control spool to switch. The incoming volume flow is redirected depending on the design of the pulse valve. However, the pulse does not serve to maintain the switching position of the valve. This is the task of holding valves, which are usually equipped with a spring return for this purpose. To increase system safety, pulse valves are therefore often additionally provided with a detent. This prevents the unintentional resetting of the control latch. Structurally, however, directional control valves with pulse control are designed so that the redirected volume flow itself ensures the holding position of the control spool.

Resetting is performed by a second pulse. Depending on the design of the pulse valve, this counter-pulse can be generated by a second pulse piston on the opposite side of the control spool or by a pulling pulse on the same side. Pulse valves with pulling pistons are more cost-effective and space-saving, but not as reliable as pulse valves with pulse pistons mounted on both sides. Therefore, they are used much less frequently.

Application of Pulse Valves

The pulse valve is a cost-effective, reliable, and energy-saving option for controlling hydraulic or pneumatic systems. It is therefore a central component of systems that are flexible and must fulfill a variety of tasks.

For small and medium-sized systems, pneumatically operated pulse valves are sufficient. This makes them less susceptible to power outages. However, compressed air always requires a pressure generator, usually an electrically operated compressor. Pneumatically operated pressure valves therefore have good emergency running properties, which can become important for the controlled shutdown of a system in the event of a power failure. In large systems, long lines can reduce the reliability of pneumatic pulse valves. Therefore, for a certain system size, electromagnetically operated pulse valves are preferred. This makes them independent of compressed air, which is not always available.

Expansion Options for Pulse Valves

Modern technology makes it possible to produce electromagnetically operated pulse valves without wiring. Since they only require a short current pulse, a locally mounted battery can provide the electrical current for operating the electromagnets. The control signal can be sent to the pulse valve via radio. This allows for the creation of electro-hydraulically operated systems that are completely decoupled from the control unit. An example of this is large military drones with hydraulic control.