Haier repeat order confirms Cannon V.A.I. a preferred method for the production of energy-efficient domestic refrigerators

By applying vacuum into the complex mould cavity where a domestic refrigerator is filled with rigid polyurethane, the V.A.I. technology facilitates the expansion of the foam into the cabinet, providing substantial benefits that convinced Haier to confirm its trust in this solution and repeat its first order, says Cannon:

• Increased productivity per foaming station: thanks to the use of highly-reactive formulations that provide a faster demoulding time, a curing cycle of around 180 s is now the reference for a side-by-side model with very thick walls, using the appropriate polyurethane chemical formulation developed by the Dow Chemical Company for this technology.
• Optimised distribution of foam throughout the whole cabinet.
• Optimum insulation performances.
• Optimum flow of expanding foam in the cabinet cavity.

A tight co-operation with Dow allowed for the joint-development of Pascal technology, an innovative chemical solution that is said to draw new frontiers in the production of refrigerators. The polyurethane chemistry developed by Dow for this technology reduces the foam thermal conductivity to a new reference level and allows for a significantly shorter polymerisation time, says Cannon.

The first industrial plant working with the Cannon V.A.I. technology, delivered to the Haier Chongqing (China) plant, has been producing its Class A refrigerators since 2011. The second V.A.I. plant of Haier is producing its high-class side-by-side wider models in the Yellow Island, Qingdao, factory, since February 2014.

Two Cannon A-System metering units, connected to four SR24 mixing heads, precisely feed the amount of foam required by each cabinet. Cannon developed a specific polymerisation 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 eight-fixture rows provide an output capacity of four foamed cabinets per minute. A patented solution, this method allows for the production of refrigerators featuring cost-effective eco-design and superior energy saving performances, says Cannon.