Control device for zero-leak directional control valves

    公开(公告)号:US10247209B2

    公开(公告)日:2019-04-02

    申请号:US15326299

    申请日:2015-07-15

    申请人: WALVOIL S.P.A.

    摘要: Hydraulic system, distributor and bidirectional valve to activate the hydraulic actuators (3; 3a, 3b) of an operating machine; the hydraulic system (1) having: a first high-pressure oil delivery (4); an oil drain (8); a slide valve with a spool, which is axially sliding and is suited to control a hydraulic actuator (3); a second low-pressure oil delivery (6); an activation valve (15); and a bidirectional valve (21) with a first passage opening (22) that can be hydraulically connected, by the slide valve (9) to the first delivery (4) and a second passage opening (23) hydraulically connected to the actuator (3); wherein, the bidirectional valve has an inlet opening (24) that can be connected, by the activation valve (15) to the second delivery (6) and an outlet opening (25) that can be connected, by the spool (12) to the drain (8).

    Modular directional valve with two or more elements of mixed type

    公开(公告)号:US10774851B2

    公开(公告)日:2020-09-15

    申请号:US16063287

    申请日:2016-12-16

    申请人: WALVOIL S.P.A.

    IPC分类号: F15B11/17

    摘要: A modular directional valve with two or more elements (E1, E2, E3, E4) in turn connectable to respective utilities (U) through the uses (A1, B1, A2 . . . B4); of which one or more elements (E1 E2) are of the CA type while one or more elements are of LS flow sharing type (E3, E4). The valve designed to be connected to a first high pressure line P1 which connects the crossing elements to a constant displacement pump (PA) and a second high pressure line P2 which connects the LS flow sharing type elements to a variable displacement pump LS, the connection to a low pressure line, the connection to a load sensing signal line (LS2) with the variable displacement pump LS (PB). Said valve acting so that if the load sensing flow sharing elements (E3, E4) fed by the line (P2) designed for the connection with the pump (PB) are in saturation, it withdraws from the carry over (6) of the group of elements (E1, E2) of the crossing type the amount of flow rate equal to the difference between the flow rate required by the utilities (U) of the elements (E3, E4) and the maximum flow rate which can be supplied by the LS pump (PB); otherwise, it freely delivers the flow rate of the constant displacement pump to the low pressure line.