控制阀提速用增压器原理分析（中英文）

增压继电器，有时也称为容积增压器，是一种气动装置，旨在以1:1的比例再现气动压力信号，但输出流量要大得多。容积增压器通常用于增加仪表空气供应的体积/流量，以加快控制阀的操作。增压继电器的示意图如下所示：

Booster relays, sometimes called as volume boosters are pneumatic devices designed to reproduce a pneumatic pressure signal (1:1 ratio), but with far greater output flow capacity. Volume boosters are typically increase volume / flow of instrument air supply for faster control valve operation. A diagram of booster relay is shown below-

工作原理

Working principle

为了理解其工作原理，下图为升压继电器的分解图

To understand working principle, an exploded diagram of booster relay is showing below- 

如图所示，当输入信号压力施加到增压器时，隔膜A对隔膜B施加向下的力。当输入腔的压力超过隔膜B的压力时，内阀被压下，允许空气从二次供气口流出。当信号压力达到排气压力时，供气阀关闭，排气通道打开，允许二次供气排放到大气中。输入口和输出口通过针阀连接。调节确保信号和输出供气压力精确平衡。上述功能允许低流量信号提供高流量输出，同时保持信号与输出压力比为 1:1。由于旁通限制，较大的输入信号变化会比执行器更快地反映在增压器的输入隔膜上。输入信号的剧烈突变会导致增压器的输入信号和输出之间出现压差。此时，隔膜会移动以打开供气口或排气口，具体取决于需要哪个动作来减小压差。端口保持打开状态，直到增压器的输入压力和输出压力之间的差值回到增压器的死区范围内。

下面列出了容积增压器的各个组成部分——

Refer to figures, when input signal pressure is applied to volume booster, diaphragm-A exerts a downward force on diaphragm B. When the force of the input chamber exceeds the force of diaphragm B, inner valve is depressed allowing air flow out the secondary supply port. On signal pressure exhaust, the supply valve closes and exhaust flow path is opened to allow exhaust of the secondary air supply to atmosphere. Input and output ports are connected by the needle valve. Adjustment ensures that exact equalization occurs between the signal and output supply. The above function allows a low volume signal to provide high volume output with pressure ratio remaining (1:1) for signal to output. Because of the bypass restriction, large input signal changes register on the booster input diaphragm sooner than in the actuator. A large, sudden change in input signal causes a pressure differential to exist between the input signal and the output of the booster. When this occurs, the diaphragms move to open either the supply port or the exhaust port, whichever action is required to reduce the differential. The port remains open until the difference between the booster input and output pressures returns to within the dead band limit of the booster.

Different parts showing in a volume booster are given below-

增压继电器的主要特点

Main Features of booster relay

快速响应——当输入信号发生剧烈变化时，增压器可提供执行器快速行程所需的流量。

可调响应——内置旁通限制器可调节增压器的响应，使执行器能够平稳地跟随缓慢的信号变化。

高效运行——软密封设计可实现严密的关闭，从而减少不必要的空气消耗，并防止定位器继电器饱和。

保持精度——增压器可根据需要实现执行器高速行程，而不会降低定位器的稳态精度。

Fast Response— Booster delivers the volume needed for rapid actuator stroking when large input changes suddenly occur.

Adjustable Response—Integral bypass restriction tunes the booster response so that smooth actuator motion follows the slow signal changes.

Efficient Operation—Soft seats provide tight shutoff to reduce unnecessary air consumption and eliminate saturation of positioner relays.

Maintains Accuracy—Booster permits high actuator stroking speeds upon demand without degrading the positioner steady-state accuracy.