Poppet valve – flow control without interference

A poppet valve is a hydraulic or pneumatic component. It takes its name from its position: instead of being integrated into the flow, the poppet valve “sits” on top of the through line. This has the advantage that, when not actuated, the valve practically does not impede the flow. This distinguishes it from spool valves.

Design of poppet valves

Poppet valves are available in three designs

• Conical-seat poppet valves
• Ball-seat poppet valves
• Disc-seat poppet valves

Conical-seat poppet valves use a ground cone as the sealing element, guided precisely onto a sealing surface. Conical-seat poppet valves are most widely used in hydraulic lines, especially in oil hydraulics. There they are used as pressure relief valves, shut-off valves, or 2-way valves.

Ball-seat poppet valves have an unguided ball as the sealing element. They are most commonly designed as check valves. In the event of a pressure drop or pressure increase, the preloaded ball closes or opens the flow path abruptly.

Disc-seat poppet valves, also simply called “disc valves” for short, have a correspondingly disc-shaped sealing element. For particularly high sealing performance, the sealing element can also be designed as a double seal. Disc-seat poppet valves are often used for automatic pressure control in a hydraulic system. As with the ball valve, control is achieved by hydraulic pressure and a compression spring in the valve. Unlike the ball-seat poppet valve, however, this control is not abrupt but very fine. A typical disc-seat poppet valve is a standard water tap. The further it is opened, the more water flows through it.

Actuation of poppet valves

When actuating poppet valves, a distinction is made between two types:

• Direct actuation
• Pilot actuation

A directly actuated poppet valve is, for example, any water tap or any shut-off valve in a hydraulic line. It is operated manually and has no further automated or centrally controlled regulation.

In pilot-operated valves, a hydraulic pilot pressure acts on the valve.

Use of poppet valves in hydraulics

Typical applications for directional poppet valves include:

• Pressure relief valves
• 2/2 to 4/3 directional control valves
• Shut-off valves (manual and automatic, e.g., check valves)

Advantages of poppet valves

The greatest advantage of poppet valves is their hermetic sealing of the flow. They do not require a leakage oil line, as they can seal the flow line with both force and form fit.
This makes them durable, reliable, and less susceptible to contamination.

They are more expensive than spool valves. However, over their service life, poppet valves are usually significantly more cost-effective. They reduce repair and maintenance costs. In addition, they contribute to the operational readiness of the hydraulic system and prevent downtime.

Development of poppet valves

The advantages of poppet valves have now been recognized in design engineering and further developed in a targeted manner. Today, poppet valves are available in a much wider range than just a few years ago. They are preferred especially in heavily loaded systems with demanding maintenance requirements.

The variety of different types and designs of poppet valves available today enables their increased use. Poppet valves can be equipped with any actuators. Mechanical, electromechanical, or pneumatic actuation is possible for both axial and radial operation of a poppet valve. Centralized control and monitoring of each poppet valve can be implemented without difficulty. Additional functions such as remote capabilities, wireless or wired, are merely a matter of technical effort. The poppet valves themselves are open to any applications and actuation methods. This makes them a preferred valve in modern applications.