During on-site inspections, if the explosion-proof wiring cavity is found to have elevated temperatures, the housing paint is discolored, or condensation is present on sealing surfaces, it often indicates that the heater has been operating long-term under conditions approaching the upper limit of its temperature group, and the selection and installation parameters need to be re-verified. The following lists the engineering parameters of the HBR-24 stainless steel explosion-proof heater by key points for on-site O&M personnel to check against.
The explosion-proof marking is Exd IIB T4 Gb, suitable for locations where Class IIB, T4 temperature group flammable gases are present. The flameproof enclosure and wiring cavity are independently sealed; the entry device is selected according to the cable outer diameter, and after installation it should be confirmed that the flameproof surface gap and fastener torque meet the requirements of the factory documents.
The allowable operating voltage error shall not exceed 1.1 times its rated value; beyond this range, the power supply quality should be checked. The heating element is a stainless steel tubular structure; insulation resistance and withstand voltage should be re-verified against factory inspection records, and cold-state insulation should be re-measured with instruments before commissioning.
When used for oil tank heat tracing, the temperature near the oil outlet is relatively high; the heater layout should take into account the flowability of the discharged oil product and avoid local overheating that could cause medium deterioration. The temperature control element measuring point should preferably be close to the oil outlet area and maintain a reasonable distance from the heating section.
Regularly check the flameproof surfaces for corrosion and the sealing rings for aging; measure the operating current and three-phase balance; record the housing temperature and compare it with the T4 group limit; during shutdown maintenance, clean surface coking and dust accumulation, and verify fastener torque after reassembly.
