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| Illustration 1 | g00719123 |
(1) Port (2) Valve (preload) (3) Port | |
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| Illustration 2 | g00719186 |
Preload valve (2) is located in line (4). Line (4) is connected to the rod side port of the ejector cylinder. | |
Preload valve (2) is a cartridge valve. The valve contains a check valve and a relief valve.
Ejecting
Oil from the rod side of the ejector cylinder flows to port (3). The pressure of this return oil rises until the pressure reaches the relief setting of the valve. This ensures that the ejector cylinder extends against a force which is a result of this back pressure. The valve prevents the ejector cylinder from extending in the incorrect sequence. This would cause a pressure rise within the rod side of the ejector cylinder which will damage the ejector cylinder.
returning
Pump oil flows to port (1). Flow from port (1) to port (3) is unrestricted. This oil flows from port (3) to the rod side of the ejector cylinder.