译文：
　　电液执行机构 　　 电液执行机构的输入信号是电信号，输出执行元件的动力源采用液压油，因此，特别适用于大推力、大行程和高精度控制的应用场合。在大型电站，为获得大推力，在主蒸汽门等控制系统中常采用电液执行机构。 　　 电液执行机构与电动执行机构比较，由于采用液压机构，因此具有更大的推力或推力矩。但液压系统需要更复杂的油压管路和油路系统的控制，例如对液压油温度、压力等的控制，还需要补充油和油的循环。与气动活塞执行机构比较，电液执行机构采用液压缸代替气缸，由于液压油具有不可压缩性，因此，响应速度可达lOOmm／s，比气动活塞式执行机构快，行程的定位xx，控制精度高(可达0．5级)，它的行程可很长(可达lm)，输出推力矩大(可达60000Nm)，输出推力大(可达25000N)。 　　 电液执行机构将输入的标准电流信号转换为电动机的机械能，以液压油为工作介质，通过动力元件(例如液压泵)将电动机的机械能转换为液压油的压力能，并经管道和控制元件，借助执行元件使液压能转化为机械能，驱动阀杆完成直线或回转角度的运动。因此，它具有电动执行机构的快速响应性和活塞式执行机构的推力大等优点。但因使用液压油，带来油路系统的泄漏等问题。 　　 基本的液压传动系统由方向控制回路、压力控制回路和流量控制回路等组成。方向控制回路可采用换向阀、单向阀等；压力控制回路可采用压力继电器、减压阀、j顷序阀等；流量控制回路可采用节流阀、调速阀等。此外，还需要一些辅助控制回路，例如平衡控制回路、卸压控制回路、增压和增速控制回路等。为保证电液执行机构的正常运转，通常采用两套液 压传动油系统，其中一套系统工作，另一套系统备用。 　　 图2—25是某类电液执行机构的工作原理图。图中，当输入信号增加时，带动力矩马达的转子转动，使挡板靠近喷嘴，仪表波纹管压力和反馈波纹管压力都增加，仪表波纹管压力的增加使喷嘴管沿支点转动，喷嘴移到圆筒的接收口，它使液压缸的上部压力增加，液压缸的下部压力降低，液压缸的阀杆下移，直到反馈弹簧力与仪表波纹管压力平衡为止。而反馈波纹管内压力的降低，使力矩马达转子返回平衡位置。 　　 与电动执行机构类似，电液执行机构也采用位置反馈装置组成反馈控制系统。它提高了整个系统的控制精度，改善了系统的动态特性。但由于价格昂贵，管路系统复杂，只有在需要大推力和推力矩的应用场合才被采用。其特点如下。 　　 1.相同输出功率条件下，液压传动装置的体积小、重量轻、结构紧凑、惯性小，响应快。 　　 2.可大范围内实现无级调速，可输出较大推力和较大力矩。 　 　3.传动无间隙，运动平稳，可实现频繁的换向操作。操作方便，易实现自动化，易实现复杂自动控制jD匝序，易实现过载保护。 　　 4.液压油黏度受环境温度影响大，也不适用于远距离传动控制。 　　 5.对控制装置的要求高，要求设置反馈装置组·成闭环控制。根据被控变量为位移、速度和力等机械量的不同，反馈检测装置也有位移检测反馈装置、速度反馈检测装置等，使整个系统变得复杂，价格上升，也提高了对维护人员的技能要求。 　 　手动执行机构 　　 手动执行机构仅在自动操作存在困难时才操作。例如，自动控制的输入信号故障或执行机构膜头漏气等，，有时在工艺生产过程的开、停车阶段，由于控制系统还未切人自动操作，这时也需要用手动执行机构对控制阀进行操作。 　　 手动执行机构的主要用途如下。 　　 1.与自动执行机构配合，用于自动控制失效时的降级操作，提高控制系统可靠性。 　　 2.作为控制阀的限位装置，限制阀的开度，防止事故发生。例如，造纸浆料制备过程中有些阀要求正常时有一定开度，用于排放粗渣。 　　 3.节省控制阀的旁路阀。在不重要的控制系统中，当管路直径较大时，可采用手动执 行机构替代旁路阀的功能，降低投资成本，缩小安装空间。 　　 4.用于开、停车时对过程的手动操作。 手动执行机构由手轮、传动装置和连接装置等组成。按安装位置可分为顶装式和侧装式两类。顶装式手动执行机构的手轮安装在自动执行机构的顶部，通过螺杆传动装置，与自动执行机构的推杆(或膜头板)连接。正常运行时，手轮退出，用紧固螺母锁定，可作为阀位{zg}位的限制装置。当需手动操作时，松开紧固螺母，转动手轮，使之与自动执行机构的推杆连接，从而可移动推杆，改变阀门开度。正作用和反作用的自动执行机构与手动执行机构的连接方式相同，但正作用执行机构需要考虑手动执行机构传动杆的密封。 　 　侧装式手动执行机构的手轮安装在自动执行机构的侧面，可采用蜗轮蜗杆传动方式，也可采用杠杆传动方式。 　 　选用顶装或侧装式手轮执行机构时，应从方便操作考虑。当控制阀安装位置较低，或阀侧没有空间时，可选用顶装式手轮执行机构，其他场合可选用侧装式手轮执行机构。为防止手轮被误操作而转动，可设置安全锁紧装置，例如，销轴固定手轮进行限位，或用小锁紧轮顶紧手轮轴等。 　 　为提供阀门位置的信息，手轮执行机构设置了刻度显示装置，用于提供阀门位置的显示 等信息。 　 　为方便进行手动操作和自动操作的切换，通常设置离合和切换装置。当手动位置时，手轮与自动执行机构的阀杆连接；当自动位置时，手轮与自动执行机构的阀杆脱钩，不影响自动执行机构的动作。 　 　其他执行机构还有齿条齿轮执行机构，它常用于旋转控制阀，由于齿隙造成回差，因此用于位式控制和控制要求不高的场合。 　 　调节机构　 　　 　　 　　　 　　 　　 　　　 　　 　　 　　控制阀的类型 　 　调节机构是将执行机构的输出位移变化转换为控制阀阀芯和阀座间流通面积变化的装置。通常称调节机构为阀，例如直通单座阀、角形阀等。其结构特点可从下列几方面分析。 　 　从结构看，调节机构由阀体、阀内件、上阀盖组件、下阀盖等组成。阀体是被控流体流过的设备，它用于连接管道和实现流体通路，并提供阀座等阀内件的支撑。阀内件是在阀内部直接与被控介质接触的组件，包括阀芯、阀座、阀杆、导向套、套筒、密封环等。通常，上阀盖组件包括上阀盖、填料腔、填料、上盖板和连接螺栓等。在一些调节机构中下阀盖作为阀体的一部分，并不分离。下阀盖用于带底导向的调节机构，它包括下阀盖、导向套和排放螺丝等。为安装和维护方便，一些调节机构的上阀盖与阀体合一，而下阀盖与阀体分离，称为阀体分离型阀，例如一些高压阀和阀体分离阀。 　 　从阀体结构看，可分为带一个阀座和一个阀芯的单座阀阀体、带两个阀座和一个阀芯的双阀座阀体、带一个连接人口和一个连接出口的两通阀体、带三个连接口(一个人口和两个出口的分流或两个人口和一个出口的合流)的三通阀体。 　 　从阀芯位移看，调节机构分为直线位移阀和角位移阀。它们分别与直线位移的执行机构和角位移执行机构配合使用。直通阀、角形阀、套筒阀等属于直线位移阀，也称为滑动阀杆阀(SlidingStemValve)o蝶阀、偏心旋转阀、球阀等属于角位移阀，也称为旋转阀(Ro-taryValve)o近年也有一些制造·厂商推出了移动阀座的控制阀，它与角行程执行机构配合，但从阀芯的相对位移看，仍是直线位移，例如Nufflo控制阀。 　 　从阀芯导向看，可分为顶导向、顶底导向、·套筒导向、阀杆导向和阀座导向等类型。对 于流体的控制和关闭等，阀芯的导向十分重要，阀芯导向用于阀芯和阀座的对中配合。顶导向采用阀盖或阀体内的一个导向套或填料结构实现导向；顶底导向采用阀盖和下阀盖的导向套实现导向，对双座阀和需要xx导向的调节机构需采用顶底导向；套筒导向采用阀芯的外表面与套筒的内表面进行导向，这种导向方式具有自对中性能，能够xx实现阀芯和阀座的对中；阀杆导向采用上阀盖上的导向套与阀座环对中，用轴套与阀杆实现导向；阀座导向在小流量控制阀中被采用，它用阀座直接进行对中。 　 　从阀芯所受不平衡力看，调节机构的阀芯有不平衡和平衡两种类型。平衡式阀芯是在阀芯上开有平衡孔的阀芯，当阀芯移动时，阀芯上、下部因有平衡孔连接，因此，两侧压力差的绝大部分被抵消，大大减小不平衡力对阀芯的作用，平衡式阀芯需要平衡腔室，因此，需密封装置密封。根据流向不同，平衡阀芯所受的压力可以是阀前压力(中心向外流向)，也可以是阀后压力(外部向中心流向)。平衡阀芯可用于套筒结构的阀芯，也可用于柱塞结构的阀芯。不平衡阀芯的两侧分别是控制阀阀前和阀后的压力，因此，阀芯所受不平衡力大，同样口径控制阀需要更大推力的执行机构才能操作。 　 　从阀芯降压看，阀芯结构有单级降压和多级降压之分。单级降压结构因两端的压差大，因此，适用于噪声小、空化不严重的场合。在降噪要求高，空化严重的场合，应采用如图 　 　在多级降压结构中，控制阀两端的压差被分解为几个压差，使在各分级的压差较小，都不会发生空化和闪蒸现象，从而防止空化和闪蒸发生，也使噪声大大降低。 　 　 从流量特性看，根据流通面积的不同变化，可分为线性特、等百分比特性、快开特性、抛物线特性、双曲线特性及一些修正特性等。流量特、J陛表示阀杆位移与流体流量之间的关系。通常，采用流量特性来补偿被控对象的非线性特性。阀芯的形状或套筒开孔形状决定控制阀的流量特性。直行，程阀芯可分为平板型(用于快开)、柱塞型、窗口型和套筒型等。图2—30是三种常用套筒控制阀的套筒示意图，由于开孔面积变化不同，阀芯移动 时，流通面积也不同，从而实现所需流量特性。柱塞型阀和窗口型阀也可根据所需流量特性 有不同形状。角行程阀的阀芯也有不同形状，例如，用于蝶阀的传统阀板、动态轮廓阀板； 用于球阀的O形开孔、V形开孔和修正型开孔等结构。 　　

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原文：
Electro-hydraulic Actuator Electro-hydraulic Actuator input signal is a signal, the output power source for the implementation of components used hydraulic oil, therefore, particularly suitable for high-thrust, large stroke and high precision control applications. In large power plants, in order to obtain large thrust, in the main steam doors are often used in electro-hydraulic control system of the executing agency. Electro-hydraulic Actuator compared with the electric actuator, due to use of hydraulic mechanism and therefore have a greater torque thrust or push. But the hydraulic system requires more complex hydraulic piping and hydraulic system control, for example, hydraulic oil temperature, pressure control, but also need to add oil and oil cycle. Compared with the pneumatic piston implementing agencies, implementing agencies using electro-hydraulic cylinders instead of hydraulic cylinders, hydraulic oil due to a non-compression, therefore, the response speed of up to lOOmm / s, compared with pneumatic piston executive body fast, stroke positioning accuracy, control accuracy high (up to 0.5), it can be a very long trip (up to lm), the output torque to push large (up to 60000Nm), the output thrust large (up to 25000N). Electro-hydraulic Actuator standard the input electrical current signal is converted to mechanical energy to hydraulic oil as the working medium, through the power components (such as the hydraulic pump) to the motor mechanical energy is converted to hydraulic oil pressure can be, and after piping and control components, With the implementation of components so that hydraulic pressure can be transformed into mechanical energy, driving straight or turning angle stem to complete the movement. Therefore, it has a fast response electric actuator and the executing agency of the thrust piston big and so on. But the use of hydraulic oil, bringing oil system for leaks and other issues. The hydraulic drive system from the direction of the basic control loop, pressure control loop and flow control loops so on. Directional control valve circuit can be used, one-way valves, etc.; pressure control loop can use the pressure relays, pressure reducing valve, j ares sequence valves, etc.; flow control loop can use the throttle, speed control valve. In addition, need some auxiliary control circuit, such as balance control loop, pressure relief control loop, pressure and growth control loop and so on. Electro-hydraulic implementing agencies to ensure the normal functioning of commonly used two sets of liquid Pressure transmission oil system, including a system work, another set of back-up system. Figure 2-25 is a class of electro-hydraulic schematic work of the implementing agencies. The figure, when the input signal increases, the drive torque motor rotor rotation, so that baffle near the nozzle, meter bellows pressure and the feedback bellows pressure can be increased, the increase in pressure bellows instruments so that the nozzle tube along the fulcrum of rotation, nozzle moving receiving cylinder port, it makes the upper part of increased pressure hydraulic cylinder, hydraulic cylinder of the lower pressures, the hydraulic cylinder valve stem down until the feedback spring force and the instrument until the pressure balance bellows. The feedback to reduce the pressure inside the bellows, so that the rotor torque motor to return the position of equilibrium. With the electric actuator is similar to the implementing agencies also use electro-hydraulic position feedback unit with feedback control systems. It improves the control precision of the whole system to improve the system dynamic characteristics. However, due to expensive, complex piping systems only need a big push and push the torque applications has been introduced. Its characteristics are as follows. 1. The same output power conditions, the hydraulic transmission device small size, light weight, compact structure, low-inertia, fast response. 2. Can be achieved within a wide range of stepless speed regulation, can output a larger and larger torque thrust. 3. Drive a seamless, smooth motion, can be realized to the operation of frequent change. Easy to operate, easy to automate, easy-turn sequence of complex automation jD, easy to achieve overload protection. 4. Hydraulic oil viscosity affected by the ambient temperature high-impact, does not apply to long-distance transmission control. 5. For control devices with high requirements, the requirements in the composition of closed-loop control feedback device. According to accused of variable displacement, velocity and volume of different mechanical strength, feedback detection devices also have displacement detection feedback device, the speed feedback detection devices, so that the whole system becomes complicated, prices, also increased the skill requirements for maintenance personnel . Manually executing agency Manually executing agencies only when there are difficulties in the operation of automatic operation. For example, the automatic control of input signal failure or the executing agency membrane head leaks, etc. Sometimes, in the process of the production process to open, stopping stage, due to the automatic control system has not yet cut operation, then the implementing agencies also need to use manual control valve to operate. The primary purpose of manually executing agencies are as follows. 1. And automatic with the implementing agencies for the automatic control failure of the downgrade operation, improve control system reliability. 2. As a control valve limit device to limit valve opening to prevent accidents. For example, the paper pulp during the preparation of some valves require a certain aperture normal for the emission of thick residue. 3. Saving control valve of the bypass valve. In the non-critical control system, when the pipe diameter and larger, can be used manually perform a body to replace the bypass valve function, reduce investment costs, reduced installation space. 4. For the opening, stopping when the process manually. Manually executing agency by the hand wheel, transmission devices and connections so on. According to the installation location can be divided into top-mounted and side-mounted types. Top-mounted handwheel manually executing agency installed on the top of the auto-executing agency, through the screw gear, and auto-executing agencies putter (or the film the first board) connection. During normal operation, the hand wheel out, with the lock nut can be used as valve position limits the maximum bit device. When the need to manual operation, release the fastening nut, handwheel, so that the implementing agencies of the putter and automatic connection, thereby moving fader to change the valve opening. Action and reaction is self-executing agencies and implementing agencies to connect manually the same way, but it is the role of implementing agencies need to consider implementing agency manual transmission rod seal. Side-mounted handwheel manually executing agency of the executive body installed in the auto side, worm gear drive can be used in a way which can be used lever transmission mode. Use top-mounted or side-mounted hand wheel implementing agency, should be considered to facilitate operations. When the control valve installation location is low or valve side there is no room, they can use top-mounted handwheel implementing agencies, other occasions, the choice of side-mounted handwheel implementing agencies. In order to prevent misuse and the hand wheel being turned, you can set the security locking devices, for example, pin a fixed hand wheel to limit, or with a small locking wheel axle and so the top tight hand. To provide information on valve position, the hand wheel scale implementing agencies set up display device, used to provide valve position display And other information. To facilitate the manual operation and automatic operation of the switch, usually set the clutch and switching devices. When the manual position, the hand wheel and automatic enforcement agencies stem connection; when the automatic position, the hand wheel and automatic decoupling the implementing agencies of the stem does not affect the self-executing agency action. The other implementing agencies are the implementing agencies rack gear, it commonly used in the rotary control valve, due to backlash caused by the backlash, so for the digital-type control and control of less demanding occasions. Regulating the type of control valve bodies Regulating institutions are the implementing agencies will be converted to changes in the output of displacement control valve spool and the valve seat area change between the flow of the device. Commonly referred to as a valve regulating mechanism, for example, through single-seat valve, angular valve. Its structural features can be analyzed from the following aspects. From a structural perspective, regulatory agencies from the valve body, valve parts, valve cover on the component, under the valve cover so on. Body is charged with fluid flow through the device, it is used to connect pipes and the achievement of fluid channels, such as valve seat and to provide parts support. Valve in the valve within the inner parts directly in contact with the accused media components, including valve core, valve seat, stem, guide sleeve, sleeve, sealing ring. Typically, the valve cover components including the valve cover, fill cavity, packing, on the cover and connecting bolts. Regulation in a number of institutions under the valve cover as part of the body is not separated. Under the valve cover for the band at the end of the regulation-oriented institutions, which includes the next valve cover bolts guide sleeve and emissions. For the installation and maintenance convenience, some adjusting mechanism on the valve cover and body unity, but under the valve cover and valve body separation, known as the separation of valve body, for example, separation of a number of high-pressure valve and valve body. From the valve structure, can be divided into a seat and a valve core with a single-seat valve body with two seat and a valve core of the double-seat valve, with a population and a link connecting the export of two pass valve with three ports (one population and two export diversion or two of the confluence of the population and an exit) and three body. Displacement from the spool of view, regulatory agencies are divided into linear displacement and angular displacement valve valve. They are the implementing agency with the linear displacement and angular displacement used in conjunction with the implementing agencies. Through valve, angular valve, sleeve valve belongs to linear displacement valve, also known as sliding stem valve (SlidingStemValve) o butterfly valves, eccentric rotary valves, ball valves, etc. to angular displacement, also known as the rotary valve (Ro-taryValve ) o In recent years, there are also some manufacturers introduced a mobile seat control valve, which travel with the angle with the implementing agencies, but the relative displacement of spool of view, is still the linear displacement, for example, Nufflo control valve. From the spool-oriented perspective, can be divided into top-oriented, top and bottom-oriented, * sleeve orientation, stem orientation and other types of seat orientation. Right In the fluid control and shut down and so on, spool orientation is important for the spool valve core and valve seat oriented toward the tie. Top-oriented use of valve cover or valve body of a guide sleeve or packing structure to achieve orientation; top and bottom-oriented use of valve cover and valve cover, under the guidance sets of implementation-oriented, right seat valves and the need for precision-oriented regulatory agencies need to use top and bottom-oriented ; sleeve-oriented use of the outer surface of the spool and the inner sleeve surface-oriented, this right of self-oriented approach performance, can accurately realize the right in the valve core and valve seat; stem orientation with the lid on the valve guide sleeve and valve seat rings, the achievement-oriented with the sleeve and the valve stem; seat orientation in a small flow control valve was used, it uses direct right in the seat. Unbalanced force suffered from the spool of view, the valve core regulatory agencies are two types of imbalance and balance. Balanced spool is a spool on the opening hole of the spool to balance, when the spool moves, the spool on the lower part due to a balance hole connection, therefore, the vast majority of pressure difference on both sides have been offset by greatly reduced unbalanced force on the spool of the role of balanced spool need to balance the chamber, therefore, need to seal sealed. According to flow in a different, balanced spool valve the pressure can be pre-pressure (center outward flows), can also be a back pressure valve (external to the center flow). Balance the spool can be used for the structure of the spool sleeve can also be used for the structure of the valve core plunger. Unbalanced on both sides of spool valves control valves, respectively before and after the pressure valve, so valve core suffered unbalanced force, the same caliber control valves need for greater thrust of the implementing agencies to operate. Step-down look from the spool, spool structure of single-stage step-down and multi-level step-down of the points. Single-stage step-down structure at both ends of the pressure due to large, therefore, suitable for low noise, cavitation is not serious occasions. In the noise reduction for high cavitation serious occasions, should be shown in Figure In the multi-stage step-down structure, the control valves at both ends of the pressure has been broken down into several pressure, so that less pressure in each classification, will not occur and the flash cavitation phenomena, in order to prevent cavitation and flash steam occurs, but also to make noise greatly reduced. From the flow characteristics of view, according to different changes in the circulation area can be divided into linear special, and so the percentage of features, quick opening characteristics, parabolic characteristics, hyperbolic and other properties and characteristics of some of the amendments. Special traffic, J Pi, said stem displacement and fluid flow relationship. Typically, the use of flow characteristic to compensate for the nonlinear characteristics of controlled object. Spool of the shape or the sleeve openings determine the shape of the flow control valve characteristics. Straight, Cheng spool can be divided into flat-type (for Quick-open), plunger-type, window type and sleeve-type and so on. Figure 2-30 is a three commonly used control valve sleeve sleeve diagram, due to changes in hole size is different spool move When the flow area is also different, in order to achieve the required flow characteristics. Plunger-type valve and window-type valves can also be based on the required flow characteristics Have different shapes. Angle valve spool stroke also have different shapes, for example, for the traditional butterfly valve plate, the dynamic contour valve plate; The O-shaped hole for the ball valve, V-shaped hole and amendment type structure openings.