Appliance leak check & drying
Air conditioning and refrigeration cooling assemblies demand stringent leak test parameters and drying process to meet the needs of product life, efficiency and address environmental concerns of today.
- Fast reaction time to maximize manufacturing throughput
- High sensitivity and repeatability to guarantee product quality
- Ergonomic & robust design for full time sniffing operation
- Highest flexibility: Helium and Hydrogen tracer gases
- Robust rotary vane pumps
How does it work?
Two main manufacturing steps are required before filling the appliance with refrigerant gas: leak check & drying, which have a direct impact on unit lifetime and performance.
After an optional gross leak test performed with air, the cooling circuit is evacuated then filled with Helium or Hydrogen tracer gas. Operators use a sniffer leak detector to pinpoint any potential leak. Leak rate specifications should match operating conditions of the test item whenever possible. Most HVAC and refrigeration systems have a typical leak rate criterion between 1 to 10 gr/year refrigerant loss. Mass loss is converted to an equivalent tracer gas leak rate: Helium/hydrogen sniffer type leak testing will go well beyond conventional leak testing methods in regard to response time, accuracy and sensitivity.
Efficiency and reliability of a HVAC-R system depends on its conditioning before the final refrigerant charge: mostly tightness, to avoid the refrigerant gas to leak out but also drying to prevent remaining moisture traces to react with refrigerant. The drying process is generally performed under vacuum, under typical pressure in the mbar range.
For leak checking, Pfeiffer Vacuum has developed the ASM 306 S, the new standard unit for HVAC-R applications. The next generation sniffer unit offers high sensitivity and fast reaction time, combined with the best in class robustness and cost of ownership.
For vacuum drying, oil sealed rotary vane pumps are commonly used, in the range of 10 to 30 m3/h pumping speed. Pfeiffer Vacuum offers DuoLine & Pascal series, a comprehensive range of robust pumps. In addition, for the most demanding assembly lines, DuoLine pumps offer optional magnetic coupling, increasing time between maintenance operation.