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DPI Plastics invests heavily in back-up power supply

DPI Plastics has made a substantial investment in back-up power to mitigate extrusion production losses caused by load shedding and general power failures.

A leading manufacturer of PVC and HDPE water reticulation and drainage pipe and fitting systems, the company is installing power generators and back-up UPS battery systems at both its Roodekop, Johannesburg and Bellville, Cape Town manufacturing facilities.

Renier Snyman, technical manager at DPI Plastics, stresses the serious repercussions of any unplanned load shedding or power outages at its main Roodekop plant, in particular. “When the power goes down, the extruder stops, leaving a certain quantity of PVC inside the machine.”

In the case of the 630 mm bore pipe extruder at Roodekop, this equates to a staggering 750 kg of material. This PVC material has limited heat stability, which means it starts to degrade as it cools down.

“When this happens, you cannot simply heat up the extruder and start the process again once the power comes back on. Basically you have got to strip the machinery first and break the PVC out of the tooling. Once the tooling and machinery are clean, it then has to be reassembled and heated up to the correct temperature before you are able to restart the line,” Snyman explains.

He points out that DPI Plastics lost an estimated R9 million worth of production in the last six months of 2014 due to a ‘perfect storm’ combination of load shedding and power outages. In 2013, DPI Plastics experienced 15 power outages in a single week. “It was a complete mess; we had virtually no production for the entire week and mountains of scrap,” Snyman recalls.

“If you try and restart an extruder that has not been cleaned properly, there is a risk that the equipment itself can be damaged,” Snyman cautions. It is for this reason that DPI Plastics decided to make a substantial investment in back-up power at both of its manufacturing facilities.

“The power back-up system will be able to keep the machines running without interruption in the event of an unexpected power cut or anticipated load shedding. This will save the downtime on the machines and lower the risk of damage, and obviously save us a lot of material that would otherwise have had to be recycled.”

Given that there are 15 PVC pipe extruders at Roodekop and seven at Bellville, this equates to a substantial cost-saving on its own. “It is quite a lot of interruption and a high tonnage of scrap produced during a power failure,” Snyman points out.

Another driver of the investment is the impact of any production delays on customer orders. “Normally you are running an extrusion line for an order. It is very seldom that we run an extruder just for stock, which means that if you have a power interruption, a customer is going to wait longer for his product.

“This can, in extreme cases, mean a construction site is held up with additional labour and machinery charges to a client of ours and possibly even delays to the final project deadline. This is also obviously going to be improve now with the back-up power system,” Snyman elaborates.

Scheduled to be completed in the first quarter of 2016, the project involves 3 MVA of back-up power at Roodekop, which is sufficient to keep the entire extrusion and mixing division and auxiliary services up and running – and about 1.2 MVA at Bellville.

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