This paper presents the results of a study investigating the assembly, durability, and leak rate of mechanical joints used in refrigerant and air-conditioning systems. A significant motivating factor of the study is identifying joint types that are suitable for use in systems that employ flammable refrigerants. In the study, three different fitting types were evaluated (press or crimp fittings, compression fittings, and flare fittings) as well as a set of brazed joints to act as a leak-free baseline. The fittings were asssembled by a combination of experienced and inexperienced technicians, and the assembly times and number of leaks observed after assembly were recorded and compared for different fittings and technician experience levels. All fittings then underwent one type of durability test: Pressure-temperature cycling, freeze-thaw cycling, or vibration testing. The fittings were then leak checked under positive pressure with R32. The results showed the press fittings resulted in the shortest assembly time, fewest assembly errors, fewest failures from harshness testing, and an acceptable leak rate. However, while more prone to failures during assembly and harshness testing, compression and flare fittings, when properly assembled and tightened, resulted in noticeably lower positive-pressure leak rate compared to press fittings.

本文介绍了一项研究的结果，该研究调查了制冷剂和空调系统中使用的机械接头的组装，耐用性和泄漏率。该研究的一个重要推动因素是确定适用于使用易燃制冷剂的系统的接头类型。在研究中，评估了三种不同的接头类型（压力接头或压接接头，压缩接头和火炬接头）以及一组铜焊接头，以作为无泄漏的基准。配件由经验丰富和经验不足的技术人员组装而成，并记录组装时间和组装后观察到的泄漏次数，并比较不同配件和技术人员的经验水平。然后，所有配件均经过一种类型的耐久性测试：压力温度循环，冻融循环，或振动测试。然后用R32在正压下对配件进行泄漏检查。结果表明，压装配件使组装时间最短，组装错误最少，粗糙度测试失败最少，泄漏率可以接受。但是，尽管在组装和粗糙度测试期间更容易出现故障，但压缩和扩口配件经过正确组装和拧紧后，与压力配件相比，正压泄漏率明显降低。