Material static accumulation characteristic tester

1、 Purpose:

This system is designed specifically to assess the static electricity risk of samples. It simulates static electricity accumulation through sliding groove friction and measures the total static charge (in coulombs) using a Faraday tube. The three static voltage sensors above the newly added chute monitor the dynamic voltage changes during the sample sliding process in real time, and can predict whether the discharge threshold is exceeded to trigger a spark explosion. At the same time, the baffle at the bottom of the chute is combined with a sensor to test the voltage accumulation and attenuation curve, indicating rapid attenuation of static electricity and reducing danger; Slow decay indicates long-term static electricity retention, and the sample maintains a high-risk state. This instrument comprehensively quantifies the accumulation, dynamic behavior, and dissipation characteristics of static electricity, assisting in the explosion-proof safety assessment of hazardous materials.

2、 Function:

The core function is to simulate the sample contact and separation process through sliding groove friction (adjustable inclination angle, optional material), so as to generate static electricity in powder/granular pyrotechnic agents. The main body of the instrument includes a Faraday tube and a picoampere ammeter, which are used to accurately measure the total accumulation of electrostatic charges released by the sliding sample inside the tube (unit: coulomb).

To break through the limitation of the original standard that can only test static charges, the innovation is to add three static voltage sensors above the chute, which can capture the dynamic voltage transient values during the sample sliding process in real time, monitor whether the discharge threshold is exceeded, and directly evaluate the risk of spark ignition; The sensor in the baffle stacking area at the bottom of the chute can measure the voltage attenuation curve of the sample after stacking, and determine the static dissipation characteristics by the attenuation rate (fast low-risk duration, slow high-risk state persistence). These components work together to not only quantify charge accumulation (in compliance with military standards), but also achieve dynamic discharge risk warning and electrostatic retention risk assessment for the first time, providing multidimensional data support for explosive safety control.

3、 Application:

Static electricity accumulation is a safety hazard that cannot be ignored in industrial production, especially in sensitive areas such as powder materials. Electrostatic discharge may directly cause combustion or explosion accidents. This electrostatic tester not only solves the problem of singularity in traditional electrostatic testing through multidimensional measurement technology, but also constructs a complete electrostatic risk assessment system. Its core value is reflected in three aspects: dynamic monitoring, risk warning, and material characteristic analysis.

Traditional electrostatic testing methods (such as GJB5891.8-2006 standard) can only measure the total amount of static charge accumulated by the sample, and this static data has obvious limitations. In practical production scenarios, the process of material friction electrification is often more dangerous than the result. When the charge accumulation rate exceeds the dissipation rate, even if the final charge amount does not reach the theoretical danger value, discharge sparks may still be caused by instantaneous high voltage during the process. Your instrument innovatively introduces three sets of static voltage sensor arrays, achieving millisecond level monitoring of dynamic changes in charge during the sliding process. This real-time data can capture transient voltage peaks that cannot be detected by traditional methods, such as pulse like voltage fluctuations generated when the sample comes into contact with specific materials in the groove. Such data is of decisive significance for identifying 'high-risk friction combinations'. During testing, a certain type of fireworks propellant was found to have a final charge of only 2 μ C (below the safety threshold), but during its descent, it generated an instantaneous voltage of 15kV due to friction with the stainless steel groove wall. This is the key reason for its repeated accidental discharges during actual transportation.

The monitoring function of voltage attenuation curve reveals the static dissipation characteristics of materials, which is a key indicator for evaluating long-term risks. The voltage time curve recorded by the sensor at the baffle can quantitatively analyze the charge retention ability of the material. For example, a test on a modified nitrocellulose showed that its voltage half-life is as long as 120 seconds, which means that once the material remains in the production equipment, its electrostatic hazard state will last for more than two minutes, making it highly susceptible to accidents due to subsequent operations. In contrast, materials with short half lives may have high instantaneous voltage, but their risk window period is short, which can be avoided by optimizing the process flow. This attenuation characteristic data can provide accurate basis for anti-static packaging design, workshop cleaning cycle formulation, etc., which is a dimension that cannot be fully achieved by existing single charge testing equipment.