On welded diaphragm accumulators (WA) the final test moves from analog to digital. The precharge value is no longer a visual reading on the pressure gauge, but a data point calculated by the software, recorded and uniquely linked to each individual accumulator through a QR code.
How the oil test on a WA accumulator works
The final test of a welded diaphragm accumulator is an oil test: by injecting oil at a pressure higher than the precharge, the WA’s diaphragm compresses the nitrogen until pressure “drops” on the gauge — that instant is the precharge value of the accumulator.
When the test is run in analog mode, the value is read by the operator on the pressure gauge. A reading of this kind, however attentive, is subjective and exposed to several variables (operator reaction time, parallax error when reading the needle, mechanical inertia of the gauge, speed of the pressure drop, etc.).
From analog to digital: what changes in WA precharge testing
The new digital test rig manages all inlet and discharge valves via software and continuously reads pressure values. The software analyses the pressure curve and its derivative: the point where the derivative shows a sharp change is the actual precharge value of the welded diaphragm accumulator, identified with no room for interpretation.
The system automatically compares the value against the tolerance range required by the customer and determines the test outcome (conforming / non-conforming). At the end of the test, the system generates a complete report: date, parameters, operating range, measured precharge value, test curve.
QR code traceability: the digital identity of every WA accumulator
A second software, developed in-house at SAIP, manages report archiving. Every WA accumulator is born with a unique QR code: the scanner at the testing station reads the code, starts the test and automatically stores the results in the product’s digital record, with date, time, outcome, and links to the report and curve.
The QR code thus becomes the single access point to the product’s full history: test data for the individual welded diaphragm accumulator and full traceability of the material batches used in its construction.
Benefits for customers choosing SAIP welded diaphragm accumulators
- Precision of the precharge value: no operator-related variability, digital value calculated and verified automatically
- Verifiable conformity: the report states whether the piece fell within the required range, with supporting values
- Full traceability: from the QR code back to the test of the individual accumulator and to the batches of the materials it is made of
- Available documentation: report and test curve remain linked to the product serial number and can be retrieved over time
Digital testing on WA accumulators is a further step toward a production process that is increasingly traceable, measured and verifiable at every stage — to the customer’s benefit.