A functional diagram of a sequence valve

A functional diagram of a sequence valve with flow through to a primary circuit is shown in Fig. 3.22. When pressure at the inlet creates a hydraulic force large enough to offset the spring force, the spool shifts to open a passage to the secondary circuit and close the primary circuit.

Figure 3 shows a cutaway view of a typical kick-down sequence valve, with a schematic representation below it. Pressurized fluid at the inlet flows up to a main poppet, through a control orifice, and to an adjustable poppet, which is held closed by spring force. Pressure tends to push the main poppet up (open), but equal pressure and a light spring on the opposite side holds it shut. When pressure builds enough to open the adjustable poppet, flow starts passing through it faster than it goes through the control orifice. This creates a pressure imbalance, so the main poppet rises. When the main poppet rises high enough to route trapped fluid through a bypass orifice, hydraulic pressure above the main poppet drops because the bypass orifice is larger than the control orifice. At this point the only force holding the main poppet shut is spring force and backpressure at the outlet port. When flow stops, spring force closes the main poppet because pressure has equalized.

这是个什么阀·？

顺序阀，楼主翻译个中文来看就更好了

学一门外语是多么的重要！