THM – FDPV & VDPV – Proportional Multi-way Directional Spool Valve

Description

THM – FDPV & VDPV – Proportional Multi-way Directional Spool Valve

Proportional multi-way directional spool valve type FDPV and VDPV according to load-sensitive principle are mainly applied to engineering machinery electric hydraulic control field to control the movement direction & speed of hydraulic oil cylinder or hydraulic motor. With various functions such as electric proportional control, electric switching value control, hydraulic control, pneumatic control, manual control, etc., such valves can realize stepless speed regulation and will not be influenced by load change. The characteristic of load sensing enables the multi-way actuators to run simultaneously and independently from each other at different speed and pressure ratings until the maximum flow of bumping source is reached.

Load-sensitive principle, applied in hydraulic system, can realize flow control of actuators without any influence of the load. Load-sensitive mechanism (fixed differential reducing valve) enables the outlet pressure to match with the changing load continuously during the working period. One side is with the function of load signal & spring force, while the other side is imposed on outlet pressure of fixed differential reducing valve which is equal to the sum of load pressure and the pressure generated by spring, namely, the differential pressure beside the throttle of proportional valve is a constant value and therefore the flow of proportional valve is only in proportional to control signal. As to the valve type FDPV, the load pressure signal passes shuttle valve, and the damper exerts a function on the spring cavity. of fixed differential overflow valve which will regulate the system pressure to the value of the sum of load pressure and spring force, so that the outlet pressure of pump can match with the load pressure. In case the load pressure is low, the outlet ressure of pump will be low and vice verse, so as to realize the energy conservation of the system.

As to multi-way directional spool valve type VDPV, the directional spool valve of each way, after selection of load pressure by shuttle valve, will deliver the maximum load pressure signal to load-sensitive port X of the variable displacement pump, and make the output pressure & ow of variable displacement pump match with the system through the control of pump’s variable displacement mechanism, so as to realize the energy conservation of the system.

As to multi-way directional spool valve type VDPV, the directional spool valve of each way, after selection of load pressure by shuttle valve, will deliver the maximum load pressure signal to load sensitive port X of the variable displacement pump, and make the output pressure & flow of variable displacement pump match with the system through the control of pump’s variable displacement mechanism, so as to realize the energy conservation of the system.

Proportional multi-way directional spool valve according to load-sensitive principle is a kind of combined-type valve, which generally consists of 3 functional elements, namely, connection block, directional spool valve and end plate. If necessary, ancillary block can be mounted on the directional spool valve additionally and intermediate block can be added between directional spool valves.

Connection block

Oil-taking way of multi-way valve is equipped with pressure oil inlet P and oil return tank port R, as well as control port LS and measurement ports Z & M. (Please refer to Section 3.1 for detailed information.)

Model selection

• In compliance with the variety of oil source, constant displacement pump and variable displacement pump
• In compliance with the specifications of connecting threads of port P and port R, G1/2, G3/4 & G1

Directional Spool Valve

Proportional directional valve shall be fixed between connection block and end plate by three screw stems (pull rods) and 12 directional spool valves can be mounted for a valve bank at most. Generally, the number of ways of the directional spool valve doesn’t exceed 8. In case the number is equal to or larger than 9, it’s suggested to divide the valves into two valve banks of multi-way valve. As to the directional spool valve with 9 or more ways, in case the system can’t be divided into two valve banks of multi-way valve, it’s required to add ZPL33/15 intermediate block or order corresponding.

enhanced-type pull rod accessory. (Please refer to Section 3.2 for detailed information.)

— In accordance with the size of working port of directional spool valve AB, G1/2 & G3/4

— In accordance with the neutral-position function and ow of directional spool valve

With or without secondary pressure limitation, N no pressure limitation, C-type pressure limitation and AB-type pressure limitation

In accordance with the operation manner, pure manual control, electronic control, hydraulic control & friction positioning With or without any auxiliary function.

End Plate

As the terminal of combined-type multi-way valve, the end plate shall be selected according to the characteristics as follows: with oil return port T controlling the internal discharge or external discharge of oil, with or without additional LS, oil inlet P, oil return port R, etc. (Please refer to Section 3.3 for detailed information.)

–With port T for pilot control of internal discharge or external discharge of return oil

–With or without additional LS inlet or cut-off of pump’ s circulation loop