The bench liquid cooling test for new energy vehicle components demands stringent pressure measurement accuracy. Prolonged high and low temperature cycling, coupled with frequent pressure shocks, can easily cause instrument zero and span drift, necessitating regular standardized calibration. Here, we present a complete set of calibrating steps that can be directly implemented on-site using the Longlv PTL535 diaphragm-type digital pressure switch tailored for battery and motor electronic control water cooling test conditions.

1. Core pain points of protection in outdoor wind power liquid cooling conditions

   All-weather rain exposure and scouring: The fan's engine room and external pipelines of the tower are unprotected. Rainstorms and typhoons bring strong water spray from multiple angles, making ordinary low-protection instruments highly susceptible to water ingress and short circuits;   Continuous dust infiltration: The wind farms in the Gobi and mountainous areas experience strong wind and sandstorms, causing fine dust to penetrate through wiring gaps, corroding circuit boards and leading to screen malfunctions;   High condensation dew + salt spray corrosion: Due to the large temperature difference between day and night, continuous condensation occurs inside the engine room. Coupled with sea salt spray in coastal wind farms, insufficient sealing can quickly rust the shell and internal components     Winter rain and snow accumulation: Under low temperature conditions, accumulated snow melts and infiltrates into the meter head, freezing the sealing structure and damaging the waterproof performance;

    Regular equipment flushing: During unit maintenance, the pipeline will be flushed with a water gun, and the instruments must withstand high-pressure water jetting.

II. Classification Standards for the Minimum Protection Level of Wind Power Outdoor Instruments

1. Inland onshore wind power (wind farms in mountains, plains, and Gobi)

The minimum protection level should not be lower than IP65, with IP66 being preferred

IP65 can completely block dust and withstand regular rainwater and low-pressure spraying; IP66 has a reinforced shell seal, capable of withstanding heavy rainstorms, strong scouring from high-pressure water jets, and long-term use in windy, dusty, rainy, and snowy environments without easily letting water in.

The basic outdoor model of Longlv PTL536 meets IP66 full-seal protection and is compatible with most inland wind turbine liquid cooling pipeline measurement points.

2. Coastal/offshore wind power (sea breeze, salt spray, strong typhoons)

The protection level of IP67 or above must be selected

The coastal area has strong salt spray corrosion, and rainstorms are prone to cause short-term water accumulation around pipelines. IP67 supports short-term immersion in water up to 1 meter deep, and multiple sealing structures prevent the penetration of salt spray and water vapor. Coupled with a stainless steel shell that resists sea salt corrosion, the instrument failure rate is significantly reduced. The PTL536 outdoor enhanced model upgrades the multi-layer sealing structure to meet the IP67 protection standard, suitable for offshore wind power liquid cooling systems.

Supplementary explanation: applicable scenarios of IP68

Only the bottom of the tower, underground water accumulation points, and long-term soaked pipelines should be selected as IP68; regular exposed liquid-cooled pipelines outside the engine room do not require IP68, as it will increase unnecessary procurement costs.

III. Advantages of Longlv PTL536 Flat Diaphragm Digital Pressure Switch in Adaptation to Outdoor Wind Power Protection

1. Multi-layer integrated sealing structure, meeting IP66/IP67 protection standards

The entire device features a fully metal-sealed enclosure, with waterproof gland fittings on the wiring terminals and waterproof rubber rings around the screen, providing multiple barriers against the intrusion of rain, dust, and salt spray. Compared to ordinary, simply sealed transmitters, it is less prone to condensation, water ingress, and screen blackout issues during long-term outdoor operation.

2. The flat membrane flush structure takes into account both anti-blocking and outdoor cleaning

The wind power hydraulic cooling medium contains trace amounts of precipitated impurities, and the PTL536 flat diaphragm end face without pressure taps has no dirt accumulation dead zones. During outdoor flushing operations, water can directly flush the diaphragms, leaving no sediment or cooling fluid impurities behind, and the cleaning process will not damage the instrument's sealing and protection.

3. Wide temperature range anti-aging shell, suitable for extreme temperature differences in wind power

The outdoor fan is exposed to low temperatures in winter and intense sunlight in summer. The shell undergoes anti-ultraviolet aging treatment, ensuring that the sealing rubber ring does not harden or crack under high and low temperature conditions, maintaining long-term stable protective performance. The internal circuit is coated with a three-proofing layer, which prevents short circuits and damage even if a small amount of moisture penetrates.

4. Digital display visibility adapts to outdoor strong light environment

Under direct outdoor sunlight, the readings on ordinary meters become blurry. This type of instrument screen is equipped with an anti-glare coating, and its IP-protected casing prevents fogging and frosting. Inspectors can clearly read the real-time liquid cooling pressure from outside the engine room and beside the tower's pipelines.

5. The signal is stable and not subject to interference from humid environments

4-20mA transmitter output + relay switch signal dual signaling, sealed enclosure isolates external electromagnetic and water vapor interference, pressure alarm and remote data transmission are not affected by rain, snow, and condensation, ensuring safe interlocking of fan liquid cooling and heat dissipation.

IV. Suggestions on protection selection for different wind power installation sites

    Inside the engine room, the liquid cooling pipeline (shielded by a ceiling) is designed to meet IP66 standards and uses PTL536, which can withstand condensation and minor cleaning sprays in the engine room;

    For the exposed pipelines outside the tower and the engine room (in inland wind farms), the standard configuration is an IP66 model, designed to withstand rainstorms and sandstorms;

    For all coastal offshore wind power sites and low-lying areas prone to water accumulation, we recommend using the IP67 enhanced PTL536, which is resistant to salt spray and can withstand short-term immersion in water;

    Water accumulation area at the bottom of the tower and underground cooling pipeline: Upgrade to IP68 high waterproof version as needed.

V. Tips for the use of protective accessories for outdoor wind turbines

    When installing the instrument, ensure that the wiring port is facing downwards to prevent rainwater from flowing into the instrument head along the cables and damaging the sealing protection;

    Regularly clean the salt spray buildup on the outer casing of coastal wind turbines to prevent corrosion of the sealing gaps and extend the service life of the protective measures;

    It is prohibited to directly use the IP65 basic model at coastal or low-lying waterlogged locations, as it is prone to water ingress and malfunction in the short term.