贝尔旋转接头概述与分类

旋转接头概述ROTARY JOINTS OVERVIEW

   旋转接头是一种旋转的机械密封装置，是为固定管路和旋转滚筒输送和排除热传导介质。应用旋转接头的热传导介质包括蒸汽，水，导热油，液压油和冷却液。

   A rotary joint, also referred to as a rotary union or rotating union, provides a mechanical seal between a stationary supply pipe and a rotating drum or cylinder to permit the flow of heat transfer media into and/or out of the rotating roll. Heat transfer media typically used with rotary joints and rotating unions include steam, water, thermal oil, hydraulic oil, and coolant.

   普通旋转接头，弹簧式机械密封可以在液体与气体介质间或介质与周围空气间提供密封隔离。旋转接头的弹簧是用以提供最初的内部密封压力，接头一旦开始运作就呈压力密封状态。低气压或真空环境依靠弹簧推力来进行密封。一般旋转接头有两种支撑形式，使用内部碳－石墨密封环的自支撑形式和采用杆或支撑架的外支撑形式。

   With conventional rotary joints, a spring-loaded mechanical seal is used to keep the fluid or gas medium from being dispersed into the atmosphere. The spring is used in the rotary joint to maintain the initial internal seating, and the rotary joint is pressure-sealed once in operation. Low pressure or vacuum service relies on the spring force to create the seal. Conventional rotary joints are either self-supported with the use of an internal carbon bushing, or external-supported using rods or a mounting bracket.

   平衡式密封旋转接头通常用于液体介质（例如，水，冷却液等），也可以用于蒸汽或其他气体介质。平衡密封技术就是依靠外部弹簧压力在旋转接头内部进行密封。介质的运行压力对密封的影响比较小。平衡式密封通常是平面密封，旋转接头通常是由球轴承支持。

   Balanced seal rotating unions are generally used with fluid service (e.g. water, coolant, etc.), but can be used with steam and other gases. The balanced seal technology relies on external spring pressure to create a positive seal within the rotating union. The operating pressure of the media has little, if any, affect on the seal load. Balanced seals are typically flat face seals and the rotary unions are usually supported by ball bearings.

   密封环是旋转接头的主要易损件。在运行时，密封环不仅承受内部流体介质的压力而且还要承受来自外管及壳体的摩擦力。因此车速，温度及介质等可以影响到密封环的使用寿命。在相当大的程度上，旋转接头实际只是一个密封外壳。质量差的密封环磨损较快，导致增加维护，停机，和维修成本。如果密封失效，那么介质泄漏会影响到纸机的加热或冷却效率。 更换一个密封环的费用相比密封失效后总经济损失小得多。

   The seal ring is the main wearing part of the rotating union. During operation, seal rings can experience internal loading forces from fluid pressure, as well as friction from contact between the sealing faces. Factors related to the machine speed, temperature, and media used can also affect the life of the seal ring. To a large extent, a rotary union is only as good as its seal package. Poor quality seals naturally wear out more rapidly, leading to an increase in maintenance, downtime, and repair cost. When a seal fails, media escapes and the efficiency of the entire heating or cooling process suffers. All of this makes the actual replacement cost of the seal just a small portion of the total cost of a seal failure.

旋转接头的分类

   随着各类成套设备工艺流程和性能的不断改进，旋转接头的种类也在不断变化增加着。旋转接头的分类方法有很多种，分类方法不同，结果也不相同，常用的几种分类方法如下。

按介质流向分类FLOW CONFIGURATION

单通式接头是指介质只按一个方向流过接头。多用于介质从缸体的一段流入，从另一端流出的情况。

In a mono-flow rotating joint, the medium flows in only one direction through the joint. A single-flow rotating joint is used where the medium enters at one end of a drum or cylinder and exits the other end, making a single pass through the joint.

双通式接头是指介质从同一个接头中流进和流出，多与虹吸管配套使用。双向式接头可在两种不同的介质或介质与周围空气间进行密封。

In a duo-flow rotating joint, the media enters and exits through the same joint. It is most often utilized in applications where syphon or distribution pipes are used. A duo-flow rotating joint seals between both media, as well as between one of the media and the surrounding atmosphere.

多通式旋转接头是指不同的介质在同一个接头中流进和流出。这些流向是可以同一个方向流动或反方向流动。

In multi-passage rotating joints, various types of media make multiple passes through the same rotating joint. These directions of flow can be in the same direction or opposing directions with any combination thereof.