Although it is not an actuator in itself, a driving form worth mentioning is the process fluid pressure itself driving the valve mechanism. The principle of self operated valves can be used for throttling or on/off applications, gas or liquid services. The process fluid can be piped directly to the actuating element (diaphragm or piston), or the pressure can be adjusted before reaching the valve actuator through a small mechanism called a pilot. The latter design allows the movement of the main valve to be controlled by an adjustable device (pilot).

先导式控制阀的一个非常常见的应用是气体压力调节，特别是对于用于为大型工业燃烧器提供燃料的燃气，如丙烷或天然气。弹簧试图迫使塞子离开阀座，而来自阀门下游侧的“反馈”气体压力作用于柔性隔膜，将塞子移向阀座。良工阀门中下游压力越小，修剪打开得越多;下游压力越大，修剪关闭的就越多。该弹簧为调压阀建立压力调节“设定值”。如果需要不同的设定点，则必须用具有不同刚度的弹簧替换弹簧。

A very common application of pilot operated control valves is gas pressure regulation, especially for gas used to provide fuel for large industrial burners, such as propane or natural gas. The spring attempts to force the plug away from the valve seat, while the "feedback" gas pressure from the downstream side of the valve acts on the flexible diaphragm, moving the plug towards the valve seat. The lower the downstream pressure in the Lianggong valve, the more open the trim; The greater the downstream pressure, the more pruning is closed. This spring establishes a pressure regulation "set value" for the pressure regulating valve. If different set points are required, the spring must be replaced with a spring with different stiffness.

这个主题的一个变体是先导加载或外部加载的压力调节器，使用外部气体压力源来建立压力调节设定点。在这里，一个简单的手动调节压力调节器用作“先导”装置，将负载压力发送到主调节器的驱动膜片顶部：外部提供的负载压力不是建立调压阀压力设定点的刚性内部弹簧。

A variant of this theme is a pressure regulator with pilot loading or external loading, which uses an external gas pressure source to establish a pressure regulation set point. Here, a simple manual pressure regulator is used as a "pilot" device to send load pressure to the top of the driving diaphragm of the main regulator: the externally provided load pressure is not a rigid internal spring that establishes the pressure setting point of the pressure regulating valve.

由于良工阀门通过转动手动设置的压力调节器上的旋钮可以轻松调节该负载压力，因此主调节器现在也可以调节。先导机构控制主气体节流机构，因此得名先导。使用先导式的安全阀具有可调节性广的优点，而非先导安全阀的调节范围通常有限。

Due to the fact that Lianggong Valve can easily adjust the load pressure by turning the knob on the manually set pressure regulator, the main regulator can now also be adjusted. The pilot mechanism controls the main gas throttle mechanism, hence the name pilot. The use of pilot operated safety valves has the advantage of wide adjustability, while the adjustment range of non pilot operated safety valves is usually limited.