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What is the process principle of high-voltage discharge leak detector?
Date: 2025-07-14Read: 4
The process principle of the high-voltage discharge leak detector is based on the difference in current response caused by changes in the electric field to determine the integrity of the seal or the lack of insulation performance of the equipment. The core process is as follows:
1、 Establishment of High Voltage Electric Field and Current Reference
1. Application of High Voltage Electric Field
The instrument applies a set value of high voltage (usually thousands to tens of thousands of volts) to both sides or surfaces of the test object through high-voltage power sources such as transformers and rectifiers. This process forms a strong electric field between the electrodes, and the measured object (such as drug packaging, insulating medium) serves as an intermediate medium for the electric field.
2. Capacitive effect in intact state
If the tested object is well sealed or has excellent insulation performance, its structure (such as packaging material) will isolate the electrode from the internal conductive medium (such as drug solution), forming an equivalent capacitance, and the current will be suppressed due to the capacitance effect and maintain a small value.
2、 Discharge response of leakage defects
1. Leakage channel forms discharge
When the tested object has physical defects (such as tiny holes or cracks), a strong electric field breaks through the dielectric at the defect site, forming a conductive channel (discharge channel) and causing the capacitance effect to disappear. At this point, the current rapidly increases, forming a detectable pulse discharge signal.
2. Microcurrent change detection
Probe (contact or non-contact) captures current mutation signals; The control system (such as microprocessor) analyzes the peak current in real time and compares it with the preset threshold. If the current value exceeds the threshold, it is judged as leakage or insulation failure.
3、 Applicable conditions and key constraints
1. Material requirements: The tested object itself needs to be insulated (such as plastic or glass packaging), and the internal medium needs to be conductive (such as liquid drugs), otherwise effective capacitance or discharge channels cannot be formed.
2. Safety design: The high-voltage power supply needs to be isolated for output, and insulation protective equipment should be worn during operation to avoid the risk of electric shock to personnel.
This method achieves rapid defect localization through non-destructive electrical testing (with a response time of approximately 0.1 seconds), and is widely used in drug packaging sealing testing and electrical equipment insulation testing.
