An ATEX certified fan from Woodcock & Wilson Ltd will give you confidence that the fan supplied has been assessed by an approved notification body to be safe, manufactured to the strictest European standards, and designed to meet the specific type of explosive or hazardous environment that it is intended to operate in, whilst also reducing the need and cost of additional testing.
South Korea, with its super high-speed internet and giant technology corporations is considered a world leader in many innovation-driven industries. The growth development of the South Korean market is impressive and unique.
As the eighth largest importer in the world, South Korea is a very attractive market for many international companies looking to sell technology and other sophisticated products. In 2021 the country announced investments totalling $432 billion USD in the semiconductor industry alone. This industry was in the news recently as it became major problem affecting manufacturing and international trade during the COVID-19 pandemic.
How are the electrostatic hazards generated and how to prevent the danger effectively?
Over time, various accidents caused by ignition, were recorded during the loading of tank trucks. For example, over 250 accidents were recorded between 1960 and 1981 in the USA and Germany. The accident rate is reducing. These accidents are all related to static Electricity, or more precisely, uncontrolled electrostatic discharge. In many accidents, although measures against electrostatics were established, uncontrolled discharge was still found to be the ignition source, after investigation.
Generation of electrostatic charge
Two surfaces in close contact (liquid/liquid or liquid/solid) will generate an electrical double layer (EDL) when they are moving relative to each other. As a result of the physical separation of the surfaces, the electrical charge separation will lead to electrostatic charging. The static electric charging rate will be increased as the speed of interface separation increases.
If the recombination of the electric charges is not possible, or when the charges cannot be dissipated, or the charges dissipate too slowly, the charges generated during the process will remain and accumulate on the surface.
Typical situations in loading operations include flowing, mixing, pouring, pumping, filtering or agitating materials, where there is forceful charge separation.
The following mechanisms lead to the accumulation of electrostatics during truck loading:
- product flow through filters and screens
- product flow through pipes or hoses
- splash during loading
- multiphase flow
The real danger arises through uncontrolled electrostatic discharge. After the potential difference between the two surfaces reaches 3 kV/mm, discharge in the form of a spark with enormous energy can easily ignite hydrocarbon products.
What can we do to protect the loading process from the hazards of static electricity?
Prevention of electrostatic hazards during truck loading
The answer is simple: prevent the accumulation of electrostatic charges on the loading equipment and tank trucks during the process and dissipate the static charges in time before they reach the limit.
According to the German Technical Rules for Hazardous Substances, practical and effective methods to prevent the accumulation of static electricity are:
- limit the filling speed (decreasing the speed of separation)
- avoid splashing of liquid
- prevent gas bubbles
- avoid a second, immiscible phase (e.g. water in the bottom of the container)
Increasing the dissipation of static charges can also be achieved by:
- increase the conductivity of the liquids (with additives)
- leave sufficient time for the relaxation of the electrostatic charge during the process
- dissipation of static electricity by grounding all conductive components
Some of the methods can be applied forcibly in an organizational way, e.g. by limiting the filling speed or not including different products in the same tank. There are still some more methods which are regarded as uneconomical or inefficient, like leaving enough time for the relaxation of static.
Theoretically, spark discharge can be easily avoided by simply grounding all conductive parts. However, experience shows that the safe grounding of all conductive parts in practice is not always that easy to ensure. This applies in particular to mobile objects that have to be grounded again and again by the staff, such as tank trucks. How to ensure a reliable and effective grounding of the tank truck?
Reliable grounding monitoring system
According to the IEC TS 60079-32-1: a grounding cable should be connected to the truck before any operation is carried out. To ensure the grounding of tank trucks, TRGS recommends a ground monitoring system (with interlock equipment) that blocks the loading or unloading process when the grounding cable is not connected or not working appropriately.
It is further recommended by IEC TS 60079-32-1 that the system should be capable of differentiating between the truck and other metal objects. This type of system can prevent operators from connecting the grounding system to objects that may be electrically isolated from the truck’s container.
The main difference between the tank trucks and the
metallic objects are their electrical properties. Tank trucks are not purely resistive. A typical tank truck nowadays has an electrical capacity and resistance. To fulfil the recommendation from the IEC TS 60079-32-1, the grounding device should be able to measure the impedance of the object. It should be capable of distinguishing between proper truck grounding and metallic parts on the gantry. It should also be able to identify the grounding connection, if the operator inadvertently connects the system to an insulated part on the truck.
The quality of the connection should be also evaluated continuously during the loading / unloading process, to ensure that the generated static charge is dissipated. Signals should be sent by the system to the control system to terminate the process, if the grounding connection is not sufficient. Meanwhile, it should also be able to indicate an unsafe situation to the operator with a light signal.
Additional safety thanks to object recognition
A modern grounding system such as TIMM‘s Grounding Control Device EKX-4 provides an object recognition function to detect the tank truck. This function prevents manipulation by connecting the clamp to other metallic parts. To realize this recognition function, the impedance (resistance and capacitance) of the connected object is measured.
According to the Health and Safety Executive’s guidance for the safe operation and use of mobile jaw crushers, equipment operators may be subject to multiple risks including exposure to dust, noise, whole body vibration and being struck by objects ejected from the crusher. Here's how, WEG’s premier distributor Technidrive, developed an energy efficient automatic jaw crusher unblock system using entirely WEG products.
Commonly used in the quarrying, mining, recycling of demolition waste and chemical industries, jaw crushers are a reasonably difficult application for systems integrators, due to the large inertia of the fly wheel, cyclic loading and differences in materials that customers feed them with.
This didn’t prove to be a problem for Technidrive, who were initially approached by a customer looking to implement a new motor in their jaw crusher machine. With over 20 years’ experience in industrial drives, Technidrive used its expertise to meet the demands of the project and exceed the initial requirements. Using a combination of quality WEG products, Technidrive was not only able to improve the efficiency and reliability of the motor, but the efficiency and safety of the entire jaw crusher system. WEG was asked to supply the motor, control and alternator for the project due to the quality, versatility and energy efficiency of its product line and its technical expertise.
Crushing is an important process in turning rock into a useable product. Rock enters the jaw crusher from the top of the machine and gets compressed between two surfaces — the fixed and moveable jaw. The rock will continue to be crushed until it is small enough to fall through the opening. Ensuring that the size of raw material is appropriately matched to the jaw opening, can alleviate blockage incidents. This can be achieved by removing oversize product prior to processing and careful control of the crusher feeder, however blockages do still occur. To unblock a crusher a plant must be shut down and the system must first be isolated, but despite these precautions a crusher can still be a serious risk to personnel, due to the amount of kinetic energy that is released during unblocking.
Technidrive wanted to develop a system that was highly energy efficient and crucially, eliminated operators from the dangerous job of manually removing blocked material from jaw crusher machines.
Technidrive commenced this project by carrying out power torque and speed calculations to decide upon a suitable selection of WEG electric motor and gear units. The electric motor was selected based on the power and speed and further mechanical calculations were carried out to ensure the motor shaft could cater for the high radial loads the application can impose. The WEG W22 motor was eventually selected for its superior cast iron frame, inverter rated windings and insulated non drive end flange.
The next vital part of the system is the control of the motor, which can incorporate a soft start or variable speed drive (VSD) to control the motor starting speed or torque, for example. The VSD model selected was a CFW11 WEG inverter with built in soft programmable logic control (PLC) functions. There were several advantages to this selection, including the standard DC bus chokes to reduce harmonics. The inverter was selected with an output sinusoidal filter to create a nice sine wave, reduce output current and importantly reduce electrical noise.
Electrical disturbances however aren’t the only consideration, crusher blockages can be a real problem for operators, resulting in periods of prolonged downtime. One of the main advantages of this project was the level of control that was achieved through an innovative piece of software, which Technidrive developed.
On a normal start from empty, the VSD ramps the crusher up on a slow ramp time, restricting the absorbed current due to the high inertia of the application. This not only keeps the power supply requirements low, for a more efficient system, but also reduces the stress on the mechanical system. Over time this can lead to significant maintenance cost savings and extend the life of the machine. It’s estimated that a 10°C reduction in operating temperature typically doubles the motor’s lifetime.
The innovative software allowed for a special start up function when starting the jaw crusher from full. In the event that the crusher is stopped full, the VSD is able to be remotely activated in an unblock mode, with a very fast ramp time in forward or reverse depending on the position of the crusher. It will continue to automatically control the direction, current, ramp times, DC bus voltage, torque, position, and speed until the product in the chamber has been cleared and the crusher has run empty for a set period of time. This innovative system removes the dangerous and laborious job operators have had to do for years, by manually unblocking jaw crushers using rock breakers or winches to remove product.
Another very important part of the system was the alternator, which is vital to achieving an efficient and reliable system. According to the International Energy Agency (IEA), 16 per cent of motor failures are due to external conditions, such as contamination, so ensuring application suitability was essential. The alternator selected was from the WEG G-line range with some special features such as a dust filtering system, to allow it to operate in a dusty quarry atmosphere, without the risk of foreign particles entering the system. The alternator also included a digital input AVR to allow remote voltage adjustment, standard I-PMG auxiliary winding system feature to allow a dynamic response to load change and short envelope compared to traditional external PMG alternators.
“The complete drive system was expertly selected to work in harmony to address many issues manufactures in the industry come across,” explained David Strain, technical director at Technidrive. “The added unblocking feature transforms the starting of the application, an often energy intensive process and provides a unique benefit for system safety. With the system supplied, we are able to provide a three-year warranty for the motor and inverter and ensure the three main parts to the drive system all work together for optimum performance and reliability. Since our first jaw crusher project, we have had much interest from other businesses in the quarrying industry. We treat each project on an individual basis, to offer bespoke turnkey systems.”
“WEG offers specialist products that are developed specifically for the rock crushing industry,” explained Russell Maccabe UK Sales Manager at WEG. “It’s vital that manufacturers and suppliers both have extensive product, application and systems integration knowledge and that’s why this project with Technidrive proved to be so successful.”
For further information about Technidrive’s range of products and services visit www.technidrive.co.uk.
Offering various benefits, demand for integrated head and face protection has, arguably, never been so high. It would seem that contractors the world over have begun to recognise the value of equipping workers with fully integrated solutions. With that in mind, there is also the hope that the efficacy and safety of PPE, rather than cost, is placed firmly at the top of the agenda for purchasing policy. Let’s take a look at the benefits integrated protection offers and the advantages of choosing greater efficacy and safety over cost.
According to new data from Delamere Health, manufacturing is estimated to be one of the most hazardous industry for workplace burnout potential during the nationwide lockdown: https://delamere.com/blog/burnout-britain-the-effects-of-the-glorification-of-grind-culture
During the coronavirus pandemic, it’s become harder and harder for Brits to maintain a work-life balance, and many of us are coming close to burnout. Nearly two-thirds of full-time workers have experienced some form of burnout in the workplace.
In the electrical world an IP rating is the rating given to a certain product to represent the quality of water and substance resistance. This is an extremely important aspect of electrical products, as if they are exposed to these elements for a prolonged period of time, then they will cease to work and can also cause injury.
The standards are set by the IP Code, or Ingress Protection Code, IEC standard 60529, (also known as the International Protection Code), and companies have to build their products to the specifications and standards, then send their products off for inspection and testing.
The IP rating is the given rating for resistance against alien substances and the rating is split in a way that will show the resistance from solid substances first, in a 1-6 rating with 6 being the best and then the second digit is the water resistance rating, which is given a 1-8 rating. It is worth noting that water resistance and being waterproof are different, water resistant is exactly what it says, a resistance, so that it cannot remain submerged indefinitely.
The international high-tech mining and mineral company LKAB always prioritises sustainability and safety in the workplace. This includes ensuring that the working environment does not expose staff to radon gas levels above the applicable limit values.
We met LKAB's work environment technician Johan Sjöström, who tells us how the company has used Radonova's personal radon dosimeters over the past year to continuously check the status of radon levels.
NW Security finds CCTV increasingly being deployed to support remote management of workplaces during COVID restrictions
A new study of CCTV system managers commissioned by security technology company NW Security, found that nearly half (46 per cent) of medium and large-sized businesses across England, plan to use their CCTV systems to support remote management of processes and people in the workplace.
For more than 10 years, Sumitec International uses Tyvek® coveralls to protect mining equipment repairmen. "Our priority is safety of our employees," says Maria Zakharova, Occupational Safety Specialist at Sumitec International. "Employees can perform a variety of work without fear of chemical contamination. For many years Tyvek® coveralls remain the best for us."