齿轮执行机构
GEAR ACTUATORS

　　如果需要，Velan阀门可配置齿轮执行机构，以满足所需要的机械性能。齿轮可以是凸形，斜角形或螺杆形。Velan的齿轮执行机构用来为所有环境和精确应用场合提供优异的、综合的、稳定可靠的性能。所有齿轮箱体都是由高强度球墨铸铁制造，适用于偶尔会遭受撞击的应用场合。轴和齿轮均配置抗摩擦轴承。所有齿轮都是采用高级合金钢并经过硬化处理。所有装置都是永久性润滑，并且是耐气候变化，可用于室外环境。
　　Velan valves are equipped with gear actuators, as required, for satisfactory mechanical advantage. Gears could be of the spur, bevel or worm type. Velan gear actuators are engineered to offer a superior combination of features for reliable and dependable service in all environmental and precision applications. All gearbox housings are produced from high strength ductile iron for service in applications where they are subject to accidental blows. Shafts and gears are all supported by anti-friction bearings. The gear sets are produced from high-grade alloy steel and hardended. All units are permanently lubricated and are weatherproof for outdoor service.

　　Velan的V系列、VT系列和VTS系列执行机构可以采用简单的螺栓适配器进行安装。可以选择凸式齿轮附件来降低手动操作扭矩。
　　Velan's V, VT and VTS series of actuators can be attached with simple bolt-on adapters. Optional spur gear attachments are available to reduce manual operating torque.

电动执行机构
ELECTRIC ACTUATORS

　　在实际应用中，几乎可以在任何位置或场所，对任何通径的阀门进行电动控制。所有装置，无论是直接安装在阀门上，还是在地基上，都可以在出现电力故障时进行手动操作。所有装置都可以配置交流电或直流电。Velan提供的电机具有高扭矩，线圈绕组经过浸渍，能够抵抗油或潮湿的腐蚀。它们完全不受气候影响，（可选）防爆、防灰尘和防蒸汽。有各种大小和类型可供用于不同应用场合和系统，并可根据各种特殊需要进行改装。
　　Motorized controls may be applied to valves of almost any size for operation in practically any position or location. All units, whether installed directly on a valve or on a floor stand, can be manually operated in case of power failure. The units are available for either alternating or direct current. Motor units supplied by Velan are the high torque type with windings impregnated to resist both oil and moisture. They are completely weather-proof, explosion-proof (optional) and dust and steam tight. Various sizes and styles are available for different applications, and systems and can be varied to fit special requirements.

液动执行机构
CYLINDER ACTUATORS

　　有各种形式的液动执行机构可用在Velan阀门上。最常用的液动执行机构是气动，但是如果需要，也可提供油动和水动。
　　Various types of cylinders are available for Velan valves. The most commonly-used cylinders are actuated by air, but oil and water types are also available if required.

　　在所有的结构中，阀杆通常相当于活塞杆，并将阀瓣直接固定在阀杆上面。标准配置包括尾杆，用于指示开关位置并在紧急情况下作为一种开启方法。手轮和齿轮头可以安装在液动执行机构的顶部用于出现缺乏运行介质的紧急状态下使用。
　　In all designs, the valve stem normally serves as a piston rod with disc fastened directly to them. Tail rods are also supplied as standard equipment to serve as position indicators and as an emergency means of opening. Handwheels and gear heads can be mounted on top of cylinders for operation in an emergency which may arise due to the loss of operating medium in the cylinder.

阀门执行机构的大小
VALVE ACTUATOR SIZING

　　Velan选择执行机构的原则是在所需要的环境下，计算操作阀门所需要的扭矩和推力。在最后选择执行机构是，总是要考虑给与执行机构在运行能力方面增加合理的余量，但是避免采用能力过大的执行机构。
　　The Velan philosophy for selecting an actuator is to calculate the required torque and thrust to operate the valve at the required service conditions. A reasonable margin of excess actuator capability over that required is always allowed for in the final actuator selection, but grossly oversized actuators are avoided.