How to Prevent Thermocouple Failure Caused by Cooling Water Leakage

An essential auxiliary structure inside injection molds, which are used to quickly chill and shape plastic items, is the cooling water circulation system. However, cooling water leakage incidents are frequently caused by pipeline aging, interface loosening, and assembly mistakes. Cooling water will seriously harm thermocouples if it seeps into the hot runner installation area. This damage can range from direct internal short circuit and irreversible burnout to erroneous temperature reading and signal instability. To safeguard temperature measurement components, comprehensive prevention and emergency treatment strategies must be developed.

There are three basic ways that cooling water leakage damages thermocouples. First, a significant amount of water vapor rapidly condenses on the surface of high-temperature thermocouple probes, causing a sharp drop in local temperature, distorted real-time temperature feedback, and a major disorder in the logic of hot runner temperature management. Second, leaked cooling water enters the interior of thermocouples that are not completely sealed. This leads to electrochemical corrosion of the internal alloy core wires, which destroys the performance of thermoelectric conversion and speeds up aging failure and performance drift. Third, water getting into wiring terminals and signal plugs might cause a line short circuit, set off an alert on the controller, or even burn out the temperature control equipment's internal signal collection modules.

The first step in daily preventive management is to make sure that all cooling water tubes are regularly inspected and maintained. Replace old hoses and sealing gaskets on a regular basis, inspect all water pipe interfaces, quick connectors, and internal circulating water channels for looseness, age, and cracking, and remove any concealed hazards from the source of water leaks. Standardize the cooling water pipeline docking procedures during mold construction and disassembly to prevent interface dislocation and loose sealing brought on by incorrect operation.

Second, arrange the hot runner thermocouple installation locations and cooling water routes as efficiently as possible. Set up drainage diversion grooves around hot runner areas to direct leaking water to flow out quickly and prevent water accumulation and infiltration, avoid dense crossing layout, and maintain a safe isolation distance between water cooling pipelines and temperature measuring holes during the early stages of mold design and processing.

Thirdly, for hot runner systems used in molds that leak readily, choose premium fully sealed waterproof thermocouples. With their superior internal waterproof and moisture-proof performance and integrated seamless sealing technology, these sensors can effectively withstand short-term water vapor erosion and significantly lower the likelihood of failure due to unintentional water seepage. Ordinary low-seal thermocouples should not be utilized in workplaces that are damp and prone to leaks.

Standardize the order of startup and shutdown procedures as well. When shutting down for maintenance, turn off the hot runner heating power supply, wait for natural cooling, and then close the cooling water switch. Avoid abruptly flushing the high-temperature hot runner with cold water to prevent water vapor backflow infiltration. Before the hot runner is heated up, connect the cooling water circulation system to ensure smooth water flow and no leaks.

The emergency remedial procedures must be rigorously adhered to if on-site cooling water leakage is discovered to be affecting thermocouple functioning state. Cut off all heating and signal power supplies right away to prevent short-circuit burnout accidents; thoroughly drain any accumulated water around the mold; use a dry air gun to blow dry moisture on thermocouple probes, wiring harnesses, and terminals; after the mold has completely dried naturally, perform a low-temperature trial heating inspection to see if the temperature display and signal feedback return to normal; replace severely corroded and failed thermocouples directly to avoid lingering issues.

Maintaining the dry and stable working environment of temperature measuring elements, preventing the unexpected shutdown of the temperature control system due to water seepage faults, and effectively isolating the negative impact of the cooling water system on hot runner thermocouples are all possible with long-term adherence to water leakage prevention specifications and prompt hidden danger troubleshooting.