Rehabilitation for failing water piping

New to South Africa is a system which rehabilitates the inner infrastructure of deteriorated or failing water piping using an array of cured-in-place epoxy pipe lining solutions. SABMiller’s brewery in Okahandja, Namibia, had a drainpipe failure. The network of pipes affected run beneath epoxy coated 30 MPA concrete floors supporting the plant’s heavy machinery and […]

Green building: Energy efficiency pays dividends

Tucked away just off busy Grayston Drive in Strathavon, Johannesburg, is a facebrick office park that does not appear to be very different to the many other stylish developments mushrooming in the area. The three-storey Upper Grayston Office Park on Linden Road is, in many respects, quite a remarkable development, especially its blocks E and […]

Lighting for “Africa’s greenest hotel”

Hotel Verde, part of the BON Hotel Group, has been dubbed “Africa’s greenest hotel” for obvious reasons. Every aspect of the hotel is designed to be as sustainable as possible, employing efficient systems to save water and electricity while reducing waste. The building features green landscaping, a vegetated roof, three 3 kW vertical axis wind […]

Case study: remote condition monitoring of London Underground track circuits

Delivering a reliable remote condition monitoring system for the London Underground to enable maintainers to respond to failures before they occur. London Underground serves 1,7-billion passengers per year and the Victoria Line accounts for 213-million of those journeys. The line carries 89,1-million passengers per year in the peak service, offering the most intensive service on […]

Arc flash mitigation and arc-resistant switchgear

Application of arc-resistant switchgear to help mitigate arc flash hazards can be a very effective way to enhance safety for electrical workers. Not only the selection of protective device types, but also selecting the settings for adjustable devices is important in the mitigation of arch flashing. Settings must be chosen to protect equipment properly while […]

The cost of poor power quality

  Productivity is the key to survival in today’s globally competitive environment. When you think about the basic inputs to production – time, labour and materials – you can see there isn’t much room for optimisation. You have 24 hours per day, labour is costly and you don’t have much choice in materials. Therefore, every […]

Fundamentals of laser welding

  There are two of types of neodymium-doped yttrium aluminium garnet (Nd:YAG) laser welder, continuous wave and pulsed. As the name suggests, continuous wave or CW is either on or off, whereas pulsed lasers create welds by individual pulses. The pulsed laser uses high peak power to create the weld, whereas the CW laser uses […]

An improved approach for connecting VSDs and electric motors

  Motor winding insulation can deteriorate quickly and the motor may fail when variable speed drives are connected to motors by long cable lengths. Within the VSD, AC supply voltage is converted into DC by means of a rectifier. DC power contains voltage ripples which are smoothed using filter capacitors. This section of the VSD […]

Designing high-pressure, high-volume pumps for harsh environments

  Pump designs fall mainly into two categories, centrifugal and reciprocating (piston) type, each with its own benefits and constraints. This article explores the design criteria and some of the applications. Information on the application and the fluids involved is key to matching the correct pump design to the application (see Fig. 1). Approaching a […]