Valve, in which the ports are connected or separated by placing a sealing element down or lifting it up. They have the advantage of being leakage-free sealed.
In terms of seated valves, a distinction is made between cone, ball and disc seated valves, depending on the design of the sealing element.
Cone-seated valves (a)
use a countersunk, guided cone as a sealing element. They are used in oil hydraulic systems as: check valves, pressure-limiting valves or 2-way plug-in valves.
Ball-seated valves (b)
use a non-guided ball as a seating element. A typical application is the Check valve. The ball prevents return flow of the fluid.
As spring-loaded versions, this valve type can also be used as a Pressure-limiting valve or as a self-actuating seal. This protects a pressure system against impermissible pressure.
Disc-seated valves (c)
also known as poppet valves, have a disc-shaped sealing element, which can easily be created in duplicate, resulting in a 3/2 directional valve. They are sealed at normal pipe pressure as the sealing disc is pressed onto the valve seat. If the pressure in the line being protected falls, the disc seal is lifted from the valve seat by the spring.
Seated valve designs
The actuation is divided into the following types:
Directly controlled: in this case, the actuation influences the control element directly. Direct actuation of valves
Pilot controlled: in this case, a hydraulic pilot pressure acts on the control element, for example. Pilot actuation
Due to the hydraulic forces that are present, directly controlled directional seated valves are available up to approx. 35 lpm. Beyond this, pilot-controlled directional seated valves are mostly used.
Directional seated valves are used in hydraulics as:
- Check valve
- Pressure-limiting valve
- 2/2, 3/2, 4/2 and 4/3 directional valves. These can also be combined in an extremely compact fashion as a valve bank and flange-mounted directly on power packs.
