Model: NL-PGQM-1
The problem
Once the water ports of an air-conditioner coil are brazed, tightness is a mandatory check: charge with 4MPa compressed air, hold for three minutes and accept only if the drop stays within 0.1MPa. Shops still fit a gauge by hand, screw in plugs and watch a stopwatch, one coil at a time, and whether a drop means a real leak or a badly seated plug comes down to experience. Coils are bulky and must be loaded horizontally, and a scratched seal face creates a false leak that costs rework.
Capability
Horizontal pneumatic clamps press sealing plugs onto both water ports at once while the remaining axial holes are closed with dedicated plugs, so two coils of the same model are tested in one load. Charging pressure is 4.5MPa and the hold pressure 4MPa, with the pressure transducer reading continuously and 0.1MPa as the acceptance line. The three-minute hold is timed automatically and any drop beyond 0.1MPa is an immediate fail, so nobody watches a stopwatch. A three-colour lamp follows the sequence: amber flashing while charging, all three colours steady during the hold, green flashing for five seconds on pass before automatic release; a fail keeps red flashing until the operator confirms. Release is closed-loop - the two-way solenoid switches charge and vent paths and the cycle only counts as vented below 0.1MPa, so the guard is never opened under pressure. A safety valve plus the pressure transducer limit the pressure, the high-pressure area sits behind an acrylic guard and over-pressure vents automatically. A Mitsubishi FX3U-32MT with FX3U-4AD analogue input and a Weinview TK6010i HMI shows pressure, hold time and leakage in real time and gives the verdict directly, in manual or automatic mode. Power-fail memory keeps the test count and state and resumes after restart; the frame is stainless steel with industrial aluminium profile and the fixture seats accept G1 and G3/4 fittings.
Key specifications
- Application: pneumatic tightness testing of air-conditioner coils DN20 and DN25
- Stations: 1, two coils of the same model per load
- Charging pressure: 4.5MPa
- Hold pressure: 4MPa
- Acceptance: hold 3 min, pressure drop within 0.1MPa
- Medium: high-pressure compressed air (0-5MPa compressor by customer)
- Clamping: horizontal pneumatic clamps seal both water ports, axial holes plugged
- Workpiece size: about L180 x 80 x 60 mm
- Control: Mitsubishi FX3U-32MT, FX3U-4AD, Weinview TK6010i HMI
- Valves: two-way high-pressure solenoid for charge and vent, safety valve
- Indication: three-colour lamp plus HMI sequence and verdict
- Data: pressure, hold time and leakage displayed, verdict recorded
Applications
Post-braze tightness inspection of air-conditioner coils in DN20 and DN25 sizes; outgoing sealing checks on heat exchangers, micro-channel coils and refrigeration piping; in-line sampling on coil production lines; incoming tightness re-check of refrigeration components
About the manufacturer
Guangdong Endurance Electronic Equipment Co., Ltd provides non-standard customization, drawing confirmation, factory acceptance, on-site installation and commissioning, operation training and long-term technical service; 12-month warranty and long-term spare parts supply. Tel: 0760-88500902 / 13416787649. Web: en.zsnaili.com.