当发生过度振动时，冷却塔振动开关触发警报和/或关闭设备有多种选择，从简单的机械开关到“智能”开关。SPX冷却技术提供以下开关类型，每种类型都具有不同的复杂程度，可帮助监测和保护冷却塔部件免受振动的潜在破坏性影响。Cooling tower vibration switches trigger an alarm and/or shut down equipment when excessive vibration occurs. A variety of options are available, from simple mechanical switches to “smart” switches. SPX Cooling Technologies provides the following switch types, each with varying levels of sophistication, which can help monitor and protect cooling tower components from potentially destructive effects of vibration.
Mechanical Vibration Switch
机械振动开关是冷却塔振动管理最经济有效的选择。然而，它往往是最不准确和最不可靠的选择。机械开关包括一个惯性敏感机构，当振动超过规定的设定值时，该机构激活一个速动开关。当开关“跳闸”时，可以同时触发警报并关闭设备。因为这些开关不收集数据，所以它们只能在振动事件发生时作出反应。在许多情况下，这对于防止故障已经太迟了；机械开关唯一能防止的是对风塔的进一步损坏。The mechanical vibration switch is the most cost-effective option for cooling tower vibration management. However, it is often the least accurate and least reliable option. The mechanical switch comprises an inertia-sensitive mechanism that activates a snap-action switch if vibration exceeds a specified set point. The switch, when “tripped,” can simultaneously trigger an alert and shut down the equipment. Because these switches do not collect data, they are able only to react to a vibration event as it is occurring. In many cases this is too late to prevent a failure; the only thing the mechanical switch prevents is further damage to the tower.
Electronic Vibration Switch
用于冷却塔振动管理的电子振动开关比机械开关有几个优点。电子开关利用固态压电晶体在振动力变形时提供4-20毫安的电输出。超过预设极限的振动会触发警报，提醒操作人员检查冷却塔，并在故障发生前将其关闭。如果在操作员手动关闭风塔之前，振动超过第二个预设限值，则开关触发固态继电器自动关闭。机械和电子开关通常安装在结构支撑梁上。另外，电子开关还提供了一个外部加速计选项，当安装在变速箱外壳上时，可以提供更高的振动测量精度。The electronic vibration switch for cooling tower vibration management has several advantages over a mechanical switch. The electronic switch utilizes a solid-state piezoelectric crystal to provide a 4-20mA electrical output when deformed by vibration forces. Vibration that exceeds a preset limit triggers an alarm, alerting operators to inspect the cooling tower and shut it down before failure occurs. If vibration exceeds a second preset limit before operators manually shut down the tower, the switch triggers a solid-state relay for automatic shutdown. Both the mechanical and electronic switches typically are mounted on structural support beams. Alternately, the electronic switch offers an external accelerometer option which provides superior vibration measurement accuracy when mounted on the casing of the gearbox.
“Smart” Vibration Switch
“智能”振动开关用于冷却塔振动管理的“智能”振动开关提供了电子振动开关的许多优点。智能开关使用内置压电加速度计测量振动。它占地面积小，外壳密封，可直接安装在齿轮箱或轴承箱上，不需要额外的外部加速计。SPX提供的智能开关具有工厂编程设定值、启动延迟和警报延迟计时器，特别针对冷却塔振动保护进行了优化。The “smart” vibration switch for cooling tower vibration management offers many of the advantages of an electronic vibration switch. The smart switch measures vibration with an imbedded piezoelectric accelerometer. Its small footprint and hermetically sealed casing allow installation directly onto the gearbox or bearing housing and does not require an additional external accelerometer. Smart switches offered by SPX feature factory-programmed set points, start-up delays, and alarm delay timers specifically optimized for cooling tower vibration protection.