恒温恒湿试验箱是各行各业不可或缺的工具,从电子、汽车到制药和材料科学,无所不包。它们能够模拟各种环境条件,用于测试产品的可靠性和耐久性。然而,与任何精密设备一样,它们也可能出现故障。了解常见问题并严格遵守维护规程是确保测试结果准确和延长设备使用寿命的关键。本指南将带您了解常见故障并提供实用的故障排除步骤。

常见问题及故障排除
当您的枪膛出现故障时,采用系统的方法可以节省时间和金钱。以下是一些最常见的问题,按症状分类。

1. 湿度控制问题
湿度问题是最常见的投诉之一。这些问题通常表现为无法达到设定的湿度值、湿度波动不定,或者显示屏始终显示100%的湿度。

症状:湿度无法上升或不稳定。

加湿器管道堵塞或空气阻塞:水中的矿物质沉积物会堵塞管道,或者空气会被困在管道内,从而阻碍水流。解决方法:用柠檬酸等弱酸性溶液清洁管道,并排出管道内的空气。

固态继电器 (SSR) 故障:SSR 控制加湿器。如果它出现故障,加湿器将无法通电。解决方法:使用万用表测试 SSR。如果发现故障,请更换为相同型号的 SSR。

过温保护器设置错误:加湿器配有过温保护器,通常设置为 130°C。如果设置过低,则会过早切断加湿器的电源。解决方法:检查控制器上的设置,并将其调整回正确值(通常为 130°C)。

症状:湿度读数为 100% 或无法控制。

Dry or Hardened Wet-Bulb Wick: The wet-bulb wick is critical for measuring humidity. If it's dry, dirty, or hard, it won't provide an accurate reading, often causing the display to show 100% RH. Solution: Check the water level in the wet-bulb reservoir. Replace the wick regularly (e.g., every two weeks) if it's dirty or has lost its absorbency.

2. Temperature Control Problems
Failures to reach or maintain set temperatures can compromise an entire test.

Symptom: The low temperature cannot be reached, or cooling is very slow.

Wet Working Chamber: If the chamber isn't dried before a low-temperature test, moisture will freeze on the evaporator, insulating it and drastically slowing the cooling rate. Solution: Before a low-temperature test, especially after a humid heat test, run the chamber at a high temperature (e.g., 100°C) for a period to bake it dry.

Poor Sample Placement: Overloading the chamber or stacking samples too tightly blocks airflow, preventing cold air from circulating properly. Solution: Ensure samples are spaced apart and do not block the air inlet or outlet. A good rule is that the sample volume should not exceed one-third of the chamber's usable volume.

Refrigeration System Fault: If the above checks are fine, the issue likely lies with the refrigeration system, such as a refrigerant leak or a faulty compressor. Solution: Check system pressures. Low pressure may indicate a leak. This requires a qualified technician to repair.

Symptom: The high temperature cannot be reached, or heating is very slow.

Air Circulation Issues: The circulation fan is responsible for distributing heat evenly. If the motor is faulty, blades are damaged, or the airflow damper is closed, heat transfer will be poor. Solution: Check the fan motor operation and ensure the damper is in the correct position. Replace any faulty components.

Failed Heating SSR or Heater: Similar to the humidity system, a failed SSR will prevent power from reaching the heater. Solution: Use a multimeter to check the heater and SSR for continuity and proper switching.

Symptom: Temperature is unstable or fluctuates widely.

Incorrect PID Parameters: The controller's PID (Proportional-Integral-Derivative) loop might need tuning. Solution: Run the chamber's auto-tune function, or if it's an older chamber, consult the manual to manually adjust the PID values to smooth out the control.

3. Alarm and Display Issues
Modern chambers have safety features that trigger alarms when something is wrong.

Symptom: High-Pressure (HP) or Low-Pressure (LP) Alarm.

High Ambient Temperature: The equipment's ideal operating environment is 5–35°C. High ambient temperatures make it difficult for the refrigeration system to shed heat, causing pressure to spike.

冷凝器脏污:灰尘和绒毛堵塞冷凝器翅片,起到隔热作用,阻碍热交换,导致压力过高。解决方法:确保冷凝器安装在通风良好、有空调的房间内。定期用压缩空气清洁冷凝器盘管。

症状:温度/湿度显示屏显示“----”或出现不规则跳动。

过温保护器跳闸:此安全装置(通常设定为温度系统约 150°C)可能已跳闸或设置错误。解决方法:检查控制面板上的过温保护器,必要时进行重置。

传感器故障:PT100 或其他温湿度传感器故障会导致读数不稳定。解决方法:检查传感器的连接和电阻。如有故障,请更换传感器。

必要的维护措施:
主动维护始终优于被动维修,而且成本更低。标准化的维护流程可以将人为故障减少 60% 以上。

日常/操作前检查(5-10分钟)
目视检查:检查门封条(密封垫)是否有裂缝或损坏。确保观察窗畅通无阻。

供水:检查水位,并用蒸馏水或去离子水补充,以防止矿物质积聚。

湿球温度计灯芯:确保灯芯清洁、柔软,并正确放置在传感器上。

每周维护(30 分钟)
清洁冷凝器:使用压缩空气吹掉冷凝器翅片上的灰尘,以确保高效的热交换。

检查和清洁:用中性清洁剂溶液擦拭内部,冲洗干净,然后擦干。

季度维护(2 小时)
校准:对温度和湿度传感器进行多点校准,以符合可追溯的标准,确保精度。

拧紧电气连接:振动会导致接线端子随着时间的推移而松动。请检查并拧紧控制面板上的所有主要电气连接。

深度清洁:清洁加湿器托盘和水管,去除水垢。

长期储存
如果储存室长时间不使用:

清空并清洁内部和水箱。

将内部彻底烘干,用 50°C 的温度运行一小时。

请将其存放在干燥通风处,避免阳光直射。

建议每月开机运行一小时,以保持压缩机处于良好状态。

关于 KOMEG

科美格公司成立于1990年,拥有超过30年的研发和生产经验,为客户提供适用于各行业的系列设备。公司主要产品包括:温湿度循环试验箱、热冲击试验箱、快速热循环试验箱(室)、ESS环境应力筛选试验箱、气候老化试验箱、高海拔温度环境试验箱、大型(步入式)环境试验箱以及其他可靠性测试设备。