原文：
一、阀门定位器 阀门定位器是气动执行器的主要附件，它与气动执行器配套使用，用来提高阀门的位置精度，克服阀杆摩擦力和介质不平衡力的影响，从而保证阀门按照调节器来的信号实现正确定位。 下列情况下，要配定位器： 1、介质压力高、压差大的时候； 2、调节阀口径大时（DN<100 3、高温或低温调节阀；="" 4、需要提高调节阀的动作速度时；="">非标准弹簧的执行机构时（20～100KPa以外的弹簧范围）； 6、用于分程控制时； 7、使阀门实现反向动作时（气关式和气开式互相转换）； 8、需要改变阀的流量特性时（可以改变定位器凸轮）； 9、无弹簧执行机构或活塞执行机构，要实现比例动作时； 10、用电信号去操作气动执行机构时，必须配电-气阀门定位器。 二、电磁阀 当系统需要实现程序控制或两位控制时，需要配用电磁阀选用电磁阀时，除要考虑交、直流电源及电压、频率外，必须注意电磁阀与调节阀作用型式的关系，可配用“常开型”或“常闭型”。 如果要求加大电磁阀的容量，来缩短动作时间，可以并列使用两台电磁阀或把电磁阀作为先导阀与大容量气动继动器组合使用。 三、气动继电器 气动继电器是一种功率放大器，它能将气压信号送到较远的地方，xx由于信号管线加长所带来的滞后，主要用于现场变送器与中央控制室的调节仪表之间，或在调节器与现场调节阀之间，还有一种作用就是放大或缩小信号。 四、转换器 转换器分为气-电转换器和电-气转换器，其功能是实现气、电信号之间一定关系相互转换，主要用于在用电讯号操纵气动执行机构时将0～10mA或4～20mA电讯号转换或0～100KPa气讯号转换成0～10mA或4～20mA电讯号。 五、空气过滤减压阀 空气过滤减压阀工业自动化仪表中的一种附件，其主要功能是将来自空压机的压缩空气进行过滤净化并将压力稳定在所需要的数值上，可用于各类气动仪表、电磁阀、气缸、喷涂设备及小型气动工具的供气源和稳压装置。 六、自锁阀（保位阀） 自锁阀是保持阀位的一种装置。气动调节阀气源发生故障时该装置能将气源讯号切断，使膜室或气缸的压力讯号保持在故障前一瞬间的状态，这样就使阀位也维持在故障前的位置上，起到保位作用。 七、阀位传送器 当调节阀远离控制室时为了不到现场就能准确了解阀的开关位置，就要配备阀位传送器，即将阀开度的机构位移量，按一定规律转换成电讯号送到控制室，此讯号可以是反映阀门任何开度的连续信号，也可以认为是阀门定位器的逆动作。 八、行程开关（回讯器） 行程开关反映阀门开关两个极端位置，并同时送出指示讯号的装置，控制室可以根据此讯号，叛断阀门的开关状态以便采取相应措施。

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译文：
1, valve positioner Valve positioner is a pneumatic actuator of the main accessories, complete with pneumatic actuator used to improve the accuracy of the valve position, to overcome friction and medium Fagan effects of unbalanced force, thus ensuring the regulator valve according to signal to achieve the correct positioning. The following cases, to go with locator: 1, medium pressure high pressure big time; 2, valve diameter is large (DN <100 3,="" high="" or="" low="" temperature="" control="" valve;="" 4,="" the="" action="" necessary="" to="" raise="" the="" speed="" control="" valve;="" 5,="" using="" standard="" signal,="" the="" operation="" of="" non-standard="" spring="" when="" the="" implementing="" agency="" (20="" ~="" 100kpa="" spring="" outside="" the="" range);="" 6,="" when="" used="" for="" sub-process="" control;="" 7,="" when="" the="" valve="" to="" achieve="" the="" reverse="" action="" (air="" to="" close="" each="" open-type="" gas="" conversion);="" 8,="" need="" to="" change="" the="" valve="">Ball Valvesvalve type of relationship, can be equipped with "Normally open type" or "normally closed." Solenoid valve if the request to increase the capacity, to reduce the movement time, you can use two parallel solenoid valve solenoid valve or the valve as a pilot and large-capacity pneumatic actuators used in combination following. 3, pneumatic relays Pneumatic relay is a PA, it will pressure the signal sent to distant places, eliminate the signal delay caused by longer pipelines, the main transmitter and the central control room for live instrumentation regulation between or the regulator valve and the scene between, there is a zoom function is to signal. IV converter Converter is divided into gas - electric converter and electric - gas converter, and its function is to achieve air, a certain relationship between the conversion between electrical signals, is mainly used in electric pneumatic actuator control signal will be 0 ~ 10mA or 4 ~ telecommunications numbers when switching to 20mA or 0 ~ 100KPa air signal into the 0 ~ 10mA or 4 ~ 20mA telecommunications number. 5, air filter regulator Air filter regulator of industrial automation instruments in an annex to its main function is to filter the compressed air from the compressor and purification of the pressure stabilized at the required value, it can be used for various types of pneumatic instruments, solenoid valve, cylinder, spray equipment and pneumatic tools for small gas source and regulator device. 6, self-locking valve (Paul position valve) Self-locking valve is a device to maintain valve position. Pneumatic valve air source failure signal the device can cut off the gas source, so the membrane chamber or cylinder pressure signal is maintained at fault before the moment of state, thus causing the valve position is also maintained at the fault position before, playing Paul-bit role. 7, valve position transmitter When the control valve away from the control room on site for less than the switch valve can accurately understand the location, it is necessary with valve position transmitter, about valve body opening displacement, according to a certain number sent to the telecommunications law into the control room, This signal can be reflected in opening the valve of any continuous signal can also be considered to be the inverse of the valve positioner action. 8, limit switch (Echo device) Travel switch valves switch reflect the two extreme positions, and simultaneously send signals of the device, the control room can be based on this signal, the switch state of rebellion off valve in order to take corresponding measures.

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