Hydraulic valves with electrical controls CETOP

Directional control valves are designed for starting, stopping and changing the direction of flow of the working fluid in pipelines, and therefore for controlling the movement and position of hydraulic actuators (hydraulic cylinders and hydraulic motors).

For panel mounting distributors (plate mounting) - CETOP all ports are displayed in a single mounting surface. With this surface, the distributors are attached to the plate by bolts, also called the main or panel to which the pipelines are connected. The connecting dimensions of the distributors and base plates are standardized, which makes it easy to replace hydraulic devices from different manufacturers. The base plate can be made as a single plate (for one distributor only), as a plate for mounting several distributors (up to 8 distributors per plate), or as a plate that can be connected to other plates with additional devices.

Distributors are classified and specified on the basis of different attributes. For example, depending on the number of external pipelines (channels, lines) connected to the distributor, they are defined as 2-way, 3-way, 4-way, etc.

According to the number of positions occupied by the control element - 2-position, 3-position and multi-position valves. So, the distributors are indicated by two digits, the first indicating the number of pipelines and the second the number of positions. For example, the 4/2 distributor designation refers to a 4-way, 2-position distributor, i.e. it is connected to four pipelines and has two positions. The most basic design is a 2/2 distributor, which has two pipelines connected and occupies two positions (closed and open position).

Two-way distributors (2/2) are rarely used, because in reality they are ordinary stopping elements. They are available in two variants - normally closed and normally open. Usually, the return to the starting position is by a spring. For the control of hydraulic cylinders with similar distributors, it takes 2 pieces for single acting and 4 pieces for double acting, which is not rational.

Three-way valves are typically used to control single acting two-position hydraulic cylinders, i.e. as 3/2 valves. There are also 3-way three-possitions distributors - 3/3 distributors, in which in the middle position the liquid from the pump is drawn to the tank. Through suitable coupling, they can also control double acting cylinders with differential action.

Four way distributors are widely used to control systems for reversing the movement of the cylinder or the hydraulic motor. The most basic implementation is the 2/2-way distributor. It provides reversible movement of the actuator without stopping in the intermediate position. The functions of the 4-way distributors are expanded by the addition of a third, central position - ie. 4/3 distributor, which depending on the purpose has a different configuration.

Open center distributors and open drainage - In the middle position connect all pipelines to the tank and ensure complete unloading of the system. This allows the cylinder of the piston to move freely under the action of an arbitrary external force (floating piston). Such valves are used if the workflow has long breaks, but it is not appropriate to stop the pump - for example, in the process of working machine tools while removing heavy and bulky workpieces.

Manifolds with open center and closed outlet - In the zero position, both sides of the hydraulic cylinder are pressurized. For cylinders with one-way rod, a fast forward motion is made, and for two-way rods the movement stops. The pump is unloaded through a safety overflow valve, which is accompanied by significant energy losses. Therefore, the distributor is not recommended in applications characterized by long breaks.

Closed center distributors and open drainage - In the zero position the piston of the hydraulic cylinder is floating, but unlike type 1, the flow of the pump to the hydraulic cylinder is blocked and its discharge is through a safety overflow valve. The pump discharge line remains under high pressure, which can be used to supply other branches of the system.

Closed center and closed distributors - With this mid-range distributor, all lines are blocked. The actuator is fixed, the pump is unloaded through a safety overflow valve or is fed by another actuator.

Closed center distributors and pump unloading - The actuator is fixed, the pump is unloaded to the tank and operates at very low pressure (with low energy losses), but cannot supply another consumer unless the latter is connected in series. This valves are suitable for long cycle breaks.
 

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