扩口式接头 Flared Tube Fittings

1、  扩口式接头概述 Flared Tube Fittings Instructions

1.1  扩口式管接头采用图8的结构型式，由三部分组成：接头体、衬套、螺母。钢管端口扩口角为37°。使用时钢管的37°扩口角紧压在接头体的锥面上，形成金属密封。使用衬套能吸收并减少管路振动和管子疲劳，并且拧紧螺母时，钢管不会跟着转动。

      As shown in Fig . 8, the fitting consists of three pieces: the body, sleeve and nut. The tube end is flared at a 37° angleand held between the fitting nose and the sleeve with the nut, providing a metal to metal seal between the fitting nose and the flare. The advantage of sleeve is reducing vibration and fatigue of tube, the stee; tube will not turn when tighten the nut.

1.2  扩口式管接头的连接螺纹有两种：公制螺纹、美制JIC螺纹

        The flared tube fitting has two connected thread: metric thread and JIC thread

1.3  扩口式管接头安装方便，不用焊接，广泛用于中低压管路系统 ，由于是金属对金属的硬密封，因此适用温度范围大

        it is easy to assemble without weld. It is especially suited for low and medium pressure systems. As metal to metal seal, it allows wide operting temperature range.

2、  扩口式接头安装   Flared Tube Fittings Assembly Insturctions

2.1  安装   Assembly

     a) 在安装前应先垂直锯下钢管（±1°以内），去掉内外径毛刺，清除脏物，需要时套上衬套、螺母后在专用设备上扩口。且尺寸D应在D1和D2之间，见图9。

     Cut tube reasonably square (within±1°),deburr the I. D. of the tube, remove the dirt. set a nut and sleeve on the tube, the tube is flared with special equipment, diameter D should fall between diameter D1 and D2, see Fig .9.

 b) 扩口式管接头半数以上的泄漏是由于扩口或安装不当引起的，安装时应使钢管、扩口轴线与接头体锥面轴线同心。

       Over half of the leakage with flared fittings is caused by impoper flaring or installation, when saaembled, the axis of the tube, the tube flare and the fitting nose should be concentric.

c) 将管子扩口面与接头体锥面对准贴紧后，用手拧紧螺母，再用扭矩扳手按扭矩建议表扳紧；如无扭矩扳手，可用普通扳手再拧紧1到2圈，一般大规格1圈，小规格2圈。

     Screw the nut onto the fitting body by hand and tighten it to the recommended torque with a torque wrench. if torque wrenches are not available, tighten 1 to 2 turns with general wrench .In general, the small fitting is tighten about 1 turn and the large fitting is tighten about 2 turns.

2.2  重复安装  Reassembly

     所有的扩口式接头都可以多次重装，但要保证零件无损坏且清洁。注意扩口无开裂。

     Fitting can be used many times. To ensure this, part must be clean and free of defects .no tube cracked.

2.3  泄漏原因  Leakage reason

  a) 安装时未对准，钢管、扩口轴线与接头体锥面轴线不同，强制将管子扳到位。

     When assembled, the axis of the tube, the tube flare and the fitting nose are not concentric, force the tube to the station.

  b) 拧紧力矩过大或过小。

     The tighten force is too large or too small.

     c) 管子扩口处开裂。

     The tube flare cracked.

     d) 接头体或管子扩口处的密封面上有影响密封的杂质、凹坑等。

     The fitting body or the tube flare is collapsed.

     e) 连接螺母松开。

     The connected nut is loosen.

     f) 过大的扭矩或多次重复使用造成接头结合密封面损坏，丧失密封性能。

     The sealing suface is damaged for longer torque or reassembly time after time.

     g) 管子扩口太大或太小，不能与接头体很好的贴合密封。

     The tube flare is too large or too small, so the seal between the fitting nose and the tube flare is not effective.