Critical tech for a cool application

KraussMaffei has brought critical insulating technology to a cool application.

Refrigerators have to be well insulated no matter where they are in the world, but in tropical climate, the need to keep perishables and drinks nicely chilled is more of a task.

In India, Whirlpool India - a subsidiary of US-based global conglomerate Whirlpool - is the market leader in manufacturing refrigerators and cooling systems. For producing the critical insulating layer made of foamed polyurethane (PUR) in the housings and doors, the company will only use KraussMaffei's RimStar mixing and metering technology.

Every day, some 6,800 refrigerators leave the Whirlpool plant in Faridabad in North India to be sold throughout India and neighbouring countries. The KraussMaffei RimStar machines, five in total, provide perfect insulation of the housings and doors, contributing to the refrigerators' exceptional energy balance. Pentamix systems providing optimum premixing of the pentane component were also part of the order.

Whirlpool is not a new customer for KraussMaffei. The collaboration started back in 2012. The first wet side equipment, a RimStar 80/80, was sent to Brazil and has been successfully

producing refrigerators in South America ever since.

Rohit Dhiman, Director Projects at Whirlpool Faridabad, said: "The RimStar system in Brazil has impressed us in recent years with its reliability and production consistency. It was only logical for us to again choose KraussMaffei when making the new investment.

"[The KraussMaffei team has] impressed us with their flexibility of timings and deep knowledge of project execution during the whole project planning and final commissioning. In total, a perfect sync with the Whirlpool team on site."

Stable process control and high product quality

The primary strengths of the RimStar systems include stable process control and high product quality. The definitive reason for this is the KraussMaffei mixing head technology. Depending on the application, the five new RimStar systems at Whirlpool are equipped with up to 10 mixing heads. For the polyurethane foaming of the refrigerator housings and doors, linear and transfer mixing heads from KraussMaffei are used in this case. The main characteristic of these transfer mixing heads is laminar and splash-free pouring of the mixture into open and closed moulds. They are particularly designed for processing hard-to-mix systems. Their other advantages include long service lives and low maintenance costs.

Another outstanding feature of the KraussMaffei RimStar machines is the particularly precise temperature control of the components, which guarantees a constant temperature at all times. In this application, pentane is employed as the blowing agent to avoid using chlorofluorocarbons. The entire equipment configuration was manufactured in accordance with German TÜV specifications, with a successful acceptance carried out onsite by TÜV-Süd.

Pentamix systems feature outstanding premixing performance

Optimum premixing of the pentane component in the production line for refrigerator housings and doors is provided by the fully enclosed Pentamix 40 premix stations from KraussMaffei. The pentane is safely introduced into the polyol component. For this purpose, a 40l high-pressure pump developed in-house is used (on the polyol side), along with a 5l plunger metering pump. High metering accuracy is achieved even at very low feed rates. The proportion is monitored by means of flowmeters for polyol and pentane. The housing is completely suction-cleaned and monitored for leaking material.

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