2023日本第5回建筑工程施工机械展

CSPI-EXPO 2023

〜次世代を担う蕞先端技術が一堂に〜

会期：2023年5月24日(水)-25日(木)-26日(金)

会場：幕張国际展览中心

主催：建設測量生産性向上展実行委員会

後援(予定)：数据科技厅　経済産業省　国土交通省　環境省

協力(予定)

土木学会  全国土木施工管理技士会連合会

日本建設業連合会  全国建設業協会

全国中小建設業協会  国際建設技術協会

建設業振興基金  日本建設機械工業会

日本建設機械施工協会  日本測量調査技術協会

日本測量協会   日本測量機器工業会

全国測量設計業協会連合会

建設コンサルタンツ協会

日本橋梁建設協会  プレストレスト-コンクリート建設業協会

ドローン測量教育研究機構  日本UAS産業振興協議会

協力展示会：ハイウェイテクノフェア (公財)高速道路調査会

Overcenter valves

The overcenter valves are employed to control the stop and the motion of one direction of an actuator (single overcenter valves) or both the directions (dual overcenter valves).

Functions:

- load lowering control: the lowering of the load is possible only if there is a pilot pressure from the other line; this operation ensures the oil supply of the cylinder preventing cavitation problems;

- containing of the pressure at the setting value, pressure relief for any pressure peaks caused by shocks or overloads;

- arrest of the flow (and of the load) when the pump is not working or the directional valve is in neutral position;

- free flow for load lifting, with reduced pressure drops;

Pilot operated check valves

Check valves are normally used to allow free flow in one direction and to stop the fluid in the opposite one, unless a pilot pressure (Ppil) is applied by the other line of the circuit.

They can be used to ensure the static lock of a load, not for dynamic control or for lowering control.

If used in combination with restrictor valves, these ones should be preferably fitted between the actuator and the pilot operated check valve, not between valve and spool valve, so that the back pressure generated by the restrictor operates against the pilot pressure applied to the valve.