MechChem Africa January-February 2021

Instrotech solution for Tshwane municipality

Bronkhorstspruit Sewage Works handles the wastewater needs of the municipality of Tshwane via a network comprising over 200 wastewater pumps that move sewage through pipelines to the works. These submersible pumps operate 24/7/365 and are unmonitored.

S hould a pump block due to heavy volume,thepumpmotorwilloverheat and burn-out. Being subterranean and unmonitored, the first sign that there is a problem is when the wastewater is seen to be over-flowing manholes and into streets. This becomes an expensive and unpleasant calamity! PreviouslyattheBronkhorstspruitSewage Works,manypumpswereover-heatingdueto blockages in the impeller, which were caused by solid materials such as diapers and other hard matter being drawn into the pump. The pump ran dry as a result, causing overheating and burn-out, and inevitable failure. AtBronkhorstspruit,Levivi22Engineering andProjects, has beencontracted toTshwane Municipality for the past four years with responsibility for projects, installation and maintenance of instrumentation, specifi- cally the maintenance of pumps that handle

wastewater (sewage). Benoit Ntabala, Levivi22 managing direc- tor explains, “I had tried a lot of different pumps, some of them well-known brand names, without satisfactory results. I then heardof Instrotech andmetwithTinus Ludik, account salesmanager at Instrotech, whowas keen to go out to the site to see our set-up, first-hand, as well as the problems we were encountering.” Instrotech’s DPM4003 & DPM3001M temperature indicators – with low and high alarm relay outputs – were recommended to measure and control the temperature of the water pumps, so that when a pump tem- perature exceeds 120 °C, it is switched off. When thepumphas cooleddown to60 °C, it is switched on again. This process repeats until

The Instrotech DPM4003 temperature indicator.

the necessary maintenance is done. The DPM4003 indicator has two NO/NC mechanical relay switches that make this possible – and up to four relay switches are available for other applications. Tinus Ludik, concludes, “At the end of July 2020, the DPM4003 temperature control- ler that we installed onto one of the pumps tripped automatically before the pump could overheat, directly resulting in a saving of approximately R600 000. “This Instrotech solutiondefinitelyensures fewer breakdowns and has the ability to save the pumps from heat failure,” he says. www.instrotech.co.za

From left: Tinus Ludik, account sales manager, Instrotech with Benoit Ntabala, MD Levivi22 Engineering, contractor to Tshwane Municipality.

14 ¦ MechChem Africa • January-February 2021