- V.A.I. (Vacuum-Assisted Injection) as efficient technology to produce refrigerators
- Highly-reactive formulations facilitate curing cycle of only 180 seconds
- Four foamed cabinets per minute
Haier, the world leader in cold appliances, is currently using their second 16-fixture Cannon foaming and polymerisation line for domestic refrigerators, featuring the V.A.I. (Vacuum-Assisted Injection) process. The first industrial plant working with this technology, delivered to Haier Chongqing (China) plant, has been producing their Class A refrigerators since 2011. The second and latest V.A.I. plant of Haier is producing their high-class side-by-side wider models in the Yellow Island, Qingdao, factory.
V.A.I. technology + highly-reactive formulation = faster demoulding & shorter curing cycle
By applying vacuum into the mould cavity, where a domestic refrigerator is filled with rigid polyurethane, the V.A.I. technology facilitates the expansion and optimized distribution of foam throughout the whole cabinet. Highly-reactive formulations provide faster demoulding leading to an increased productivity per foaming station. A curing cycle of around 180 seconds is now the reference for a side-by-side model with very thick walls .The appropriate polyurethane chemical formulation has been developed by The Dow Chemical Company (Dow). The polyurethane chemistry reduces the foam thermal conductivity and allows a significantly shorter polymerization time.
16 curing jigs, aligned in two 8-fixture rows: 4 cabinets per minute
Two Cannon A-System metering units, connected to four Cannon SR24 mixing heads, feed the amount of foam required by each cabinet. Cannon developed a specific polymerization jig for this technology, in which the refrigerator cabinet is maintained under a controlled degree of vacuum during the whole period of the foam’s injection. A centralised vacuum station provides in each mould the negative pressure required at a very constant level for the whole period of the chemicals’ injection and of the foam’s expansion. Sixteen curing jigs, aligned in two 8-fixture rows provide an output of four foamed cabinets per minute.
Picture: Two new Cannon FPL SR 24 mixing heads feed eight polimerisation jigs placed in a row.