Cement delivery under pressure with new MPA guidelines
To reduce the number of accidents within the quarry and cement industry, new guidelines have been introduced by the Mineral Products Association (MPA) to address the problem of over-pressurization of storage silos during tanker delivery of cement. This new document is an update of the earlier version
which was produced in conjunction with the Health and Safety Executive to tackle the problem and standardize on a best practice solution.
The objectives are simple, to reduce or eliminate risk and improve health and safety by following best practice guidelines for silo protection. The consequences of an over-pressurization on a typical
cement silo range from an expulsion of cement into the atmosphere and surrounding area causing environmental issues to damage to the silo and the filters with the consequential risk of death or serious injury to personnel and the public working within the vicinity.
In order to understand what is required for a safe silo protection system during a fill, we need to explore the dynamics of the delivery process and the typical problems that will arise during the bulk delivery to site. By applying logic to the control and monitoring of this process a safe system for both site and delivery tanker operators is provided.
The guidance notes set out by the MPA state that over-pressurization can occur due to one or more of the following:
  • increase in flow rate of air from the tanker at the end of a discharge;
  • overfilling of the silo;
  • failure of the pressure relief valve to vent flow rate from the tanker;
  • inadequate flow through the filters;
  • inadequate maintenance or design of the above equipment; and
  • uncontrolled discharge of residual air from the tanker.
In order to identify a solution for the above points it is necessary to explore how the problems arise and how they can be controlled in a safe manner to eliminate problems of over- pressurization of a silo in the future.
 
DELIVERY PROCESS
The road tanker delivering the cement carries a load of up to 44 tonnes and is fitted with a compressed air blowing system which provides the air to transport the powder from the tanker to the silo. These tankers operate at pressures up to 2 bar (29psi) and the belly or tank on the vehicle is a pressure tested and a certified vessel. The tank is pressurized via the on-board compressor, and the powder is fluidized through a distributor plate ready for discharge through the control valve on the vehicle.
These parameters are all controlled manually and monitored during the discharge process by the tanker driver. The outlet from the tanker is connected via a flexible hose and couplings to the inlet pipe of the silo. The pipe and fittings are all pressure tested and certified to a pressure of approximately 5 bar (73psi). At the bottom of the inlet pipe to the silo is an auto shutoff valve which is triggered by a pressure or level alarm in the silo but on many older systems there is nothing at all. From the point where the cement leaves the delivery truck there are no other components in the system which are pressure certified, including the silo itself.
Typically silos will not withstand a pressure greater than 0.07 bar (1psi) before rupturing or splitting, as they are only designed to withstand the load of the material inside. With supply pressures 30 times greater than this, the risk of accidents is clear. The air is then blown into the silo along with the cement. The cement will then fall out of suspension as it enters the silo and the air is vented through the silo filter to atmosphere. At this point not all of the cement dust falls from suspension and a small percentage does get drawn into the outlet filter however most designs will automatically clean themselves to prevent blockages during a delivery.
When a delivery is taking place it is imperative that the tanker driver has sufficient experience to monitor the noise of the product being discharged and the movement of the flexible hose as these are the only indicators which he has of the flow rate of powder into the silo. Mass flow of the powder being discharged into the silo is very important because the airflow into the silo will increase when the powder density is reduced, and this is particularly important towards the end of a delivery, to prevent a surge of air into the silo. This part of the filling process which relies on the experience of the delivery driver must be monitored very carefully during each delivery.
One of the main cause of incidents as identified by the MPA was increase in flow rate at the end of discharge.
The maximum air flow rate into the silo is most likely to occur at the end of the delivery process, when the tanker is nearly empty and may be pressurized up to 2 bar (29psi). At this time the silo will be close to being full and have the minimum ullage or free space. Under these conditions the pressure of 2 bar (29 psi) is connected directly to the silo which commonly cannot withstand a pressure much over 0.07 bar (1 psi) and this air needs to be vented very rapidly out to atmosphere through the silo ventilation filters. If the filters cannot discharge this air
quick enough the pressure relief valve, which must be sized to pass the maximum free flow from the delivery vehicle compressor, will activate releasing product into the atmosphere but if this is not operational or is incorrectly sized the silo is at risk of rupturing or blowing the filter housing off the silo roof. All of these incidents have occurred in the past.
It should be noted that whilst tankers have ‘on-board discharge units’ to avoid venting the tank via the silo, these systems rely on the experience of the driver to recognize that the silo is nearly full and take manual control in order to make use of this facility.
To try and prevent the above scenario from happening it is good practice to have the operation of the pressure relief valve tested frequently, ideally before each delivery, but this is not practical and requires someone climbing to the top of the silo and these people need to be qualified and equipped to comply with the ‘Working at Heights Regulation 2005’.
There were 44,152 reported slips trips and falls in 2009/10 which account for 36% of all reported industrial injuries to employees and 28% of all fatal injuries to workers involve a slip, trip or fall accident. It is obviously essential to reduce the risk of accidental falls and to this end most leading cement companies have introduced several adaptations to their tanker delivery fleets to reduce the need for drivers to climb on them by providing ground level air and electrical lines for coupling semi trailer’s and providing ground level sampling points to allow drivers to provide their customers with product samples. Both of these avoid ‘working at height’ to reduce the risk of falls and since the tanker height is much lower than the height of a silo any protection system should follow the same example.
The solution is available and relatively simple, fit an automatic monitoring and control shut off system to the silo.
 
AUTO SHUT OFF SILO PROTECTION SYSTEMS
It is the build-up of pressure that threatens the environment, damages a silo and endangers site personnel or the public. Due to the nature and speed of this pressure increase, which could be due to any number of faults, the safety control must be automatic and failsafe. It must respond immediately without the need for any human intervention.
At the very least, an auto shut off silo protection system must consist of a pressure sensor, a high level probe and a pressure relief valve all linked to an auto shut off control panel, with outputs for control and alarm. It must be capable of being tested to ensure that all the major elements are working correctly before every delivery without the need for an operator to have access to the top of the silo, i.e. ground level testing.
The auto shut off system will control the silo inlet valve, closing if a pre-set high pressure or high level condition occurs. If it fails to close the inlet valve and the pressure continues to rise, then the PRV will open to vent the excess pressure.
If we now explore the individual components we begin to understand how total silo safety with advanced ground level testing is achieved and we can eliminate the six major areas of concern as raised by the MPA in their guidance notes with an added benefit of reducing maintenance costs where these systems are fitted.
 
SILO PRESSURE SENSOR,THE HEART OF SILO PROTECTION
In order to control the pressure in the silo it is essential to continuously monitor it. The pressure sensor module is the critical first line of defence, measuring the pressure in the silo as the fill takes place. If this pressure exceeds the safe working pressure of the vessel it must take action, activating alarms and closing the discharge valve in the fill pipe line.
Hycontrol has developed an innovative method for completing the ground level test and checking of the integrity of all the major components within a silo protection system. One simple button press, before every delivery, is all that is required.
A unique patented pressure sensor from Hycontrol is protected by a porous membrane. It is electronically tested and cleaned in a single operation. It is activated by a small air supply connected to the pressure sensor which applies a fixed pressure of approximately 90% of full range output, directly to the pressure sensor face. This change in pressure is measured by the system and verifies correct operation over its full operating range. As the air escapes through the porous membrane at the end of the sensor tube it removes any build up of material. If the membrane is blocked or damaged and the air pressure cannot pass through then the system alerts the operator and does not allow filling to take place until the situation is remedied.
This device requires air to test its functionality. This is commonly taken from the air used to clean the filters as it is readily available close by. This then provides the added benefit that the sensor will not pass the GLT test if the air to the filter is not switched on, or is at an insufficient pressure providing an additional safety test. This pressure sensor will eliminate the uncontrolled discharge into the silo from either the end of the delivery cycle, or discharge of residual air into the silo, by automatically closing the inlet valve before the over-pressurization can occur. 

INADEQUATE FLOW THROUGH THE FILTERS
Silos that are pneumatically filled have a filter installed on the silo roof that is sized for the peak airflow when filling. The most common filter system used is the filter bag or filter cartridge system. These require cleaning which is usually carried out automatically, either by reverse jet cleaning (blowing air back through the filters) or mechanical shaking to remove the dust.    It is extremely important that they do not lose efficiency due to blockages and so the Hycontrol Silo Protection System logs the number of high-pressure events which occur providing a valuable record to show if a high pressure has been reached regularly. This record is invaluable as it indicates either that the filters require maintenance or the tanker drivers are transferring powder at too high a pressure both of which require an action to prevent future risks of over pressurization.
 
OVERFILLING OF THE SILO
This is prevented by the integrated level control device, typically a capacitive or vibrating level probe that is designed to switch when the product buries its sensitive tip, indicating near full capacity and that filling should stop.
Failure to stop filling can result in product release into the environment, blocked lines, blinded filters and potential damage to the pressure relief valve.
The type of high level probe selected is also vitally important. Vibrating probes with a single diamond knife blade provide reliable high level switching for powdered materials without any need to calibrate. Importantly they have a ground level test facility to ensure that the probe operates and functions correctly before every delivery. Whilst overfilling a cement silo with cement causes an environmental issue the great danger is the blinding of the filters which can have catastrophic results. The Hycontrol system logs every high level event to enable operators to analyse their deliveries and improve their working practices.
 
FAILURE OF PRESSURE RELIEF VALVE AND A BIG MISUNDERSTANDING
If the pressure in the silo exceeds the maximum operating pressure allowed, this safety valve will open to atmosphere, not only releasing air but also releasing product into the surrounding area. The valve is designed to protect the silo against physical damage and should be the last line of defense in a well designed silo protection system.
The biggest misconception is that by fitting a pressure relief valve to your silo you are ‘safe’ and that it is acceptable to have a
pressure relief valve open on a regular basis. If we examine the reasons for a PRV venting to atmosphere it
is firstly because the silo protection system has failed and secondly because the air could not escape to atmosphere quick enough. Both scenarios need to be addressed as this could indicate a filter problem due to blockage, incorrect size or the air entering the silo is not being controlled by the tanker driver in the correct manner.
The Hycontrol PRV has an integral test facility operated from ground level.This physically lifts the PRV at the correct pressure and confirms its operation as part of the ‘one button, one press ground level test’. Hycontrol’s PRV also has the added advantage of a local test button so that the valve can be opened for inspection and cleaning without any special tools being required, something previously impossible to do.
 
THE NEXT GENERATION OF SILO SAFETY
The new guidance notes from the Mineral Products Association indicate that one of the major contributory factors to incidents of over pressurization is poor maintenance and all equipment used in the discharge process must be maintained to ensure correct functionality. To date this has not been practical or possible, as to remove pressure sensors and pressure relief valves to test and check is too costly and time consuming and necessitates working at heights.
The new generation of silo safety systems from Hycontrol, are fully compliant with the latest guidelines providing full testing of all primary elements before each and every delivery. Only when all these safety devices have passed a test will the safety interlock allow the silo inlet valve to open thus ensuring that no delivery commences without all elements functioning correctly.
The new Hycontrol Silo Protection System fully tests the PRV, high level probe, and the pressure sensor leading to vastly improved silo safety.
The need to check instrumentation for protection on a daily, weekly or monthly regime has now ended. The new Hycontrol silo protection system provides peace of mind for site operatives and has the added bonus of reduced maintenance costs to help your budget.
 
 
Efficient way to transport cement with ContiTech conveyor belts
Conveyor belts transporting material for cement production must meet stringent requirements, writes Christoph A. Seeger, Head of Sales for Industry World, ContiTech Conveyor Belt Group.
Above all, they have to be flexible, robust and temperature- resistant. As a specialist in its field, the ContiTech Conveyor Belt Group offers the right solutions. That’s because the conveyor belts in the ContiTech range ensure eco-friendly, safe and cost- effective conveyance — throughout the entire production process.The following is an overview.
 
CONVEYING AS REQUIRED — RIGHT FROM THE START
With its extensive product range, ContiTech is capable of tending end-to-end to the needs of cement manufacturers. Right after the limestone is blasted, a first conveyor belt already comes into use in the stone-crushing process. It has to be up to dealing with rock measuring as much as 500mm. The sharp- edged limestone can be very heavy in some cases, so the conveyor belt has to compensate for extremely high impact energy. Conveyor belts equipped with a protective fabric or steel breaker are just right for the job. This includes conveyor belts like the CONTIFLEX RipProtect, the Con-Montex or the Con-Bitex.
As new additions to the ContiTech portfolio, Con-Montex and Con-Bitex conveyor belts boast a special EPP fabric structure that greatly restricts expansion. A thicker cover layer in the requisite stock reduces the impact energy generated when rocks hit the belt.
 
EFFICIENT IN ALL AREAS
The fractured limestone usually has a long journey ahead of it before arriving at the cement plant for further processing. This can involve distances of several kilometres, as not every cement plant is located in the immediate vicinity of a quarry. The conventional fabric belts in the CONTIFLEX range are particularly suitable for this purpose, as are STEEL CORD belts. The latter can optionally be equipped with EOB-quality cover stock. Energy-optimized cover stock can make a conveyor belt system considerably more efficient. With their pollution- preventing closed construction,TUBE BELTS present still another alternative. They are also capable of bridging curves of smaller radii. TUBE BELTS can also carry material on the system’s return run. This makes it possible to transport a wide variety of materials back to the feeding point via the same route — a decisive advantage for many system operators. Con-Montex and Con-Bitex belts are another alternative here. These newly developed belts save operators money in terms of
maintenance, servicing and replacement and thus help reduce downtime and save costs.
 
SAFE AND LONG-LASTING
Conveyor belts with a high level of operational safety are required for the conditioning (storage, homogenization and grinding) of raw materials. The CONTIFLEX fabric belt fills the bill here. CONTI CLEAN A-H conveyor belts, however, also provide good service in this type of job — especially in the transport of highly abrasive filler materials. An ultra wear- resistant surface makes the belts much more durable than conventional conveyor belts. The special conveyor belt’s non- stick plastic coating repels dirt and prevents any wet material conveyed from caking. This minimizes cleaning costs and machine downtime.
 
CONVEYOR BELTS HELP WITH ENERGY PRODUCTION
A key stage in cement production is the firing process. The energy required for this comes not only from conventional sources like coal (also transported on conveyor belts), oil or gas, but also from biomass or scrap tyres. To convey materials of this type, cement plants use belts with special cover stock characteristics — the CONTIFLEX OIL (with oil- and grease-resistant surfaces), for instance, or SICON belts (for ultra space-saving transport of shredded tires). The extremely flexible SICON belts, in particular, can transport material through narrowest clearances.
 
DEFYING EXTREME TEMPERATURES
After firing, the thermometer reads far above 200°C.The resulting ‘hot’ clinker presents a particular challenge for the conveyor belt. Belts with standard cover stock cannot be used for this purpose, as they can withstand temperatures only as high as roughly 80°C. ContiTech has the right answer here: CONTIFLEX VULKAN, with temperature-resistant cover stock. Its special design ensures that elevated temperatures do not damage tensile members.
 
ON THE RIGHT TRACK
The end of the process is the packing and loading of the cement. For jobs like this involving metering and weighing systems, ContiTech has conventional fabric conveyor belts in its CONTIFLEX range, as well as special transport belts with scalloped edges and profiles in its FLEXOWELL and MAXOFLEX product ranges. These conveyor belts are ideal for transporting loose bulk material over steep routes.
 
SERVICE WRIT LARGE
As a major manufacturer and service provider, the ContiTech Conveyor Belt Group offers a complete line of service materials for the cement industry. This starts with individual splicing materials for belt installation. It also encompasses corrosion- and wear-inhibiting lining material such as CORREX and ABS. TRANSCORREX drum linings, on the other hand, help the conveyor system to a much better transmission of force. Then there are cold repair products like CONREMA for maintaining and servicing belts or unvulcanized cover stock for hot- vulcanization repairs. And finally the range of service materials
also includes cold adhesives such as ContiSecur BFA or assembly solutions. ContiTech is always at the customers’ side with technical support and advice as well as design calculations. It is likewise quite willing to provide on-site assistance.
For decades, ContiTech conveyor belts have stood for the highest quality. This will not change any in times of rising raw material prices. The ContiTech Conveyor Belt Group maintains an extensive dealer network, with representations on all the world’s continents. Decades of experience and ongoing development enable the company to offer the cement industry solutions optimized repeatedly for energy-efficiency, cost- effectiveness and safety.
 
CONTITECH WITHIN CONTINENTAL
With sales of €26 billion in 2010, Continental is among the foremost automotive suppliers worldwide. As a supplier of brake systems, systems and components for powertrains and chassis, instrumentation, infotainment solutions, vehicle electronics, tyres and technical elastomers, Continental contributes to enhanced driving safety and global climate protection. Continental is also an expert partner in networked automobile communication. Continental currently has approximately 155,000 employees in 45 countries.
The ContiTech division holds a global market leadership position for non-tyre rubber technical elastomer products and is a specialist in plastics technology in the non-tyre rubber sector. The division develops and produces functional parts, components and systems for the automotive industry and other important industries. It employs some 26,000 staff and generated sales of some €3.1 billion in 2010.


Hazard monitoring in the cement industry with Watchdog ‘Elite’ from 4B Braime
Conveying systems in the cement industry are exposed to difficult operational conditions. Cement is a heavy duty application where dust contamination and the heavy weight of the material and high temperatures puts strain on the system components and can lead to early wear- out and failures.
Although the potential risk of cement causing a dust explosion is low compared to other materials, the kiln which is at the heart of every cement plant has been the source of a number of explosions in the industry. The kiln is fired using either, powdered coal, oil, natural gas, or more recently waste materials, and reaches temperatures of around 1,600° Celsius.The areas at each end of the rotary kiln produce dust and hot fumes which must be cleared and made safe. Any conveying system used around the kiln or for the transportation of coal and cement should be carefully monitored for the risk of explosion hazards.
 
THE BUCKET ELEVATOR
Bucket elevators with high heat steel cord belts are increasingly being used (replacing less efficient chain elevators) to convey both coal and cement, often operating at temperatures of up to 160° Celsius. The bucket elevator is one of the most efficient methods for moving bulk granular materials, but it is also one of the most dangerous. The dust generated from the movement of materials within the elevator can be highly explosive, and mechanical failure or incorrect operation of the bucket elevator can have catastrophic consequences. The most common hazards are belt misalignment, belt slippage, blocked chutes, and bearing failures each of which should be monitored to reduce the risk of fires, explosions or breakdowns that result in costly downtime.
 
MULTI-HAZARD MONITORING SYSTEMS
Over the years, many different types of monitoring systems have been designed and implemented. All use either electronic, mechanical, or electro-mechanical transducers mounted on the bucket elevator or the conveyor. These transducers pass signals to a control device, which usually provides visual/audible warnings and automatic shutdown of the bucket elevator or conveyor when dangerous or improper operating conditions are
identified. Designers attempt to engineer these systems to operate in fail- safe modes, which can assure correct operation of the monitoring system when a dangerous condition occurs or a failure is
Watchdog Elite hazard monitoring system.
Bucket elevator shown with hazard monitoring sensors.
imminent. They are a great tool for plant maintenance engineers as they give an instant overview of the different areas monitored through one central control unit.
4B’s Watchdog ‘Elite’ is a multifunctional hazard monitoring system for bucket elevators and conveyors that monitors belt speed, belt and pulley alignment, bearing temperature, and plug condition. The Watchdog ‘Elite’ features the latest solid state electronics and fail-safe design principles to ensure the most, accurate and reliable monitoring all the time.
Belt speed and belt alignment monitoring utilizes extended range magnetic proximity sensors to detect either steel elevator bucket bolts or steel elevator buckets. These sensors have an adjustable sensing range of 0-100mm, and are not affected by any amount of dust or material build-up. A high temperature version is available for temperatures up to 180° Celsius.
 
BELT SPEED
The sensors provide a single digital pulse for each target (bolt or bucket) passing through the sensing field. These digital pulse signals correspond to the speed of the elevator belt and are translated and averaged by the Watchdog control unit.
 
BELT ALIGNMENT
Two sensors are arranged so that during normal belt alignment both sensors detect the passing targets and during belt misalignment only one sensor detects the passing targets. This arrangement is simply achieved by installing the sensors on the outer edge of the steel bolt heads or on the sides of the steel buckets. When the control unit is receiving two signals the belt is aligned correctly. When the control unit receives only one signal the belt is misaligned.
Normal belt ‘wander’ is allowed for by adjustment of the sensing range and the position of the sensors from the targets during system installation and commissioning.
The benefits of using this type of non-contacting continual sensing system are two fold.
Firstly, there is no contact with the components being monitored; therefore, no parts to wear out and no dangerous contact with the belt. Secondly, the system is actively processing signals during normal operation, ensuring fail-safe operation as no signal indicates an unsafe condition.
 
CONTROL UNIT
Using the latest available technology, the Watchdog ‘Elite’ control unit processes the signals received from the speed and alignment sensors through dual PIC microprocessors. A menu system displayed on the liquid crystal display (LCD) allows for easy parameter adjustments, which are accessed via a password and three panel mounted push buttons. Calibration and set-up parameters are retained in a non-volatile EPROM memory chip.
 
DISPLAYS
The bright light emitting diode (LED) display provides continuous indication of belt speed, and the LCD screen provides operators with clear and concise messages on the status of the monitoring system and the operation of the bucket elevator or conveyor.
 
PARAMETERS & TEST
Underspeed and misalignment alarm and shutdown trip points are adjustable within industry regulations via the password protected set-up menu.
The Watchdog system and all associated external wiring, warning and shutdown controls can be fully tested through the menu system.
 
OUTPUTS
The control unit provides three standard outputs for control of external equipment;
alarm relay, shutdown relay, and RS485 serial comms. The alarm relay provides an output to warn operators when a system fault has been detected. The shutdown relay provides an output to automatically stop the elevator or conveyor under a fault condition. Both of these outputs have user definable trip points and both operate in a fail-safe mode (relay energized during normal running conditions).
The third output is used for serial communication with a computer or PLC system. Using a four-wire RS485 network cable, this output provides information on elevator or conveyor operation and control unit status. Additional control units can be ‘daisy-chained’ on the network as the system is expanded.
In addition to the three standard outputs, an optional interface board provides isolated relay contacts for belt underspeed, belt misalignment and bearing temperature. This option is useful for simple integration to PLC’s or computers when the RS485 network capability is not utilized.
 
OPTIONAL AUXILLARY SENSORS
Bearing temperature
The temperature of the elevator or conveyor bearings are
monitored using positive temperature coefficient (PTC) bearing temperature sensors. These zinc-plated steel sensors thread into the grease zerk location on the bearing housing, providing positive mounting. The sensor housing is grease-through and incorporates a standard grease nipple for bearing lubrication. The sensors wire back to the control unit, which provides a warning, followed by an automatic shutdown when an over- heated bearing is detected.
The location of the failed bearing is displayed on the LCD screen to allow for rapid location and rectification. Negative Temperature Coefficient (NTC) bearing temperature sensors are available which display the temperature of the bearing.
Plug condition monitoring
When an elevator or conveyor discharge becomes plugged, material is forced down back into the machine, quickly filling up the casing of the elevator or (enclosed) conveyor, resulting in belt slip and possible severe damage to the machine. A capacitance-style 4B proximity sensor mounts in the discharge section or discharge spout of the elevator or conveyor and can provide early warning of plug conditions. In high temperature applications a Remote Autoset can be used which has remotely mounted electronics and probes suitable for temperatures up to 600oC.
A continuous signal from the sensor to the control unit indicates a normal plug-free condition, and an open signal occurs up on a plug condition.The control unit translates this signal and displays ‘plug condition’ on the LCD screen and can automatically shut down the elevator or conveyor.
Head pulley alignment- monitoring
Under certain mechanical fault conditions, the head pulley of an elevator can move over and rub against the elevator trunking, while the elevator belt remains normally aligned. This can lead to severe damage or explosion, and the head pulley alignment should be monitored at all times. The Watchdog system incorporates a head pulley alignment monitoring option, which uses solid state inductive proximity sensors to monitor head pulley position. The non-contacting sensors provide a signal to the control unit when the head pulley is running within normal operating parameters and deactivates the signal under a misaligned condition. The control unit activates a warning device, displays ‘head pulley misalignment’, and after a delay period, can automatically shut down the elevator.
 
APPROVALS
The Watchdog ‘Elite’ system is ATEX approved for zones 21 and 22 and also carries CSA and IECEx approvals.
 
SUMMARY
The Watchdog ‘Elite’ system uses the latest solid state electronics and provides accurate and reliable safety monitoring for bucket elevators and conveyors. Some of the key features of the system are as follows:
  • non contacting fail-safe belt speed monitoring
  • non contacting fail-safe belt alignment monitoring
  • solid-state electronic bearing temperature sensors
  • solid-state electronic sensors for plug condition monitoring
  • non contacting electronic head pulley alignment sensors
  • acceleration monitoring during elevator start-up y slack or broken chain detection
  • user adjustable trip points and parameter customization
  • simple password protected menu system with front panel push buttons for set-up and parameter adjustment
  • large bright LED speed display
  • LCD message/warning panel display
  • display in English, French, Spanish, or German
  • non volatile EPROM memory chip
  • passive and active system test which verifies Watchdog system function and correct working of all external wiring and associated equipment
  • ATEX, CSA and IECEx approved
 
The Watchdog ‘Elite’ is essentially a ‘Guardian’ system, constantly monitoring for a change condition indicating a potential performance failure. An extremely user-friendly and reliable system, the Watchdog ‘Elite’ hazard monitoring system has established itself as the industry standard product for hazard monitoring in bucket elevators and conveyors.
The 4B group has been a pioneer in developing hazard monitoring systems for the bulk handling industry. 4B’s electronics division specializes in level controls, intelligent sensors and safety control systems that prevent costly downtime and minimize the risk of explosion in hazardous areas.
 
 
A clean sweep: keeping cement works spotless with Dulevo equipment
The importance of cleanliness within cement works, and cement handling areas, cannot be underestimated, both from a health and safety viewpoint, and also in order to safeguard the environment from pollution.
Italian company Dulevo International offers a range of cleaning solutions for a wide variety of applications; cement works are among the areas that are regularly cleaned using the company’s equipment.
Dulevo was founded in 1976 based on the inspiration and abilities of a group of technicians working in the Province of Parma, who created the first prototype of the model 120 industrial sweeper. The immediate success of this initiative became the incentive to set up the first manufacturing workshop in a small garage in Parma, where, barely a year later, the model 90 saw the light of day. The market’s approval of the newborn Dulevo machines was immediate and the brand spread rapidly all over Europe. It was in 1991 that what had become Dulevo International was now to grow into the great industrial corporation that it is today. In fact, the entry of the Lampogas Group gave rise to a frenetic research and development activity that led to industrializing the product and creating a number of new models in all market segments. Intense penetration into the world markets meant the company gained its prestigious position, growing finally into the huge organization that it is today.
Lampogas s.p.a., a leading company in the distribution and sales of GPL was founded in Parma in 1954 and from then onwards, thanks to the experience and entrepreneurial skill of its founders, is recognized as the top Italian private company in the sector. The Lampogas Group is currently made up of 25 corporations operating in Italy and seven companies operating in eastern Europe.
Thanks to this new drive and to more than thirty years of experience, Dulevo has attained and consolidated a top-level market position. All this has contributed to a company ethos that has created success at world level; never take anything for granted and be always on the look out for new horizons.
Dulevo International maintains its position in the market through an ongoing search for solutions and technologies that can improve the quality of the environment we live in, passionately pursuing the best technical solutions to solve any cleaning requirements for commercial, industrial and urban environments.
Furthermore, thanks to its mechanical-suction-filtering sweeper system, Dulevo gives top priority to overcoming environmental noise and dust emissions (PM10). Dulevo’s tireless drive to seek optimal solutions works in achieving excellence both in technology and quality, bringing constant innovation to its products and services with the intention not only of meeting its clients’ expectations, but, indeed, of surpassing them.
Dulevo International is now the largest manufacturer in Italy in the industrial and the urban cleaning sector. Its new industrial facility is one of the world’s most advanced production plants in the sector, located on a site of 200,000m2 that accommodates 20,000m2 of production and a state-of-the-art R&D area, where the models of the future are constantly being developed. To date, Dulevo is in a position to guarantee an annual production of approximately 3,000 machines, ranging from floor scrubber- dryers to commercial, industrial and street sweepers.
Dulevo Hydro Power is a dynamic manufacturer of scrubber-
dryers for professional cleaning. The experience and specific competence of the team of professionals who have created them are combined with the industrial resources and high qualitative standards of a leading company with the enviable international reputation of Dulevo International Spa.
This effective synergy makes it possible to maintain the same total quality value of the products together with the personal care it gives to its relations with dealers, providing consistent and dedicated attention, flexibility and maximum attention to design and production and, finally, distribution.
Dulevo prides itself on its will to continue producing functional and competitive solutions aimed at the genuine requirements of the market and of its commercial partners, guaranteeing reliable assistance and support anywhere in the world.
The range of scrubber-dryers for floors offers a targeted and customized solution for all requirements; starting from model H402C with 35cm scrubbing width and reaching model H47 with 1.25m and a steel frame, intended for the heaviest industrial work. The whole range of scrubber-dryers, which has recently been increased by two new models (H1020 and H1220), features the highest quality materials and parts, as well as the greatest care in assembling them.
All the models are available in the electrical version by mains connectionorbattery. Thestainlesssteelwasteandwater tanks, a further generation of electronic components, the extraordinary washing and drying operations, make these Dulevo machines the choice of an ever increasing number of users. Within the scrubber-dryer Dulevo Hydropower range, the ideal solution can be found for cleaning any premises, be they offices, supermarkets, showrooms, hospitals, schools, gyms, food industries, etc.
The range of industrial sweepers starts with the model 52 for use by a standing operator and progresses to the model 5000 for any external industrial application. Dulevo International is the only manufacturing corporation to use an identical ultra-fine filtering method in all its models, just adapting to the size of the various types of application. Dulevo not only designs and assembles each model in its range, but also designs and builds the frame.
This first allows full control over each component and, therefore, secondly ensures the quality of each individual machine leaving the different production lines.
 
The industrial sweepers can be divided into three different main areas of application.
  • from model 52 to model 75: for light applications both in small and medium industrial areas; such as storerooms, workshops, small aprons and all similar applications where the use of water is not required.
  • from model 1100 to model 120: for heavier applications both in small and medium industrial areas, especially where total control of dust is essential during the sweeping, as in cement works, steel works, aluminium factories or any other industrial application where the collection of large waste is important, such as ports, container terminals, etc.
  • from model 200 to model 5000: special models thanks to their combined system patented by Dulevo International, for mechanical sweeping – suction, for any industrial application requiring exceptional results in the least time possible, in working conditions that are quantitatively and qualitatively extremely heavy duty.
 
 
Rush service helps Izmir Cimentas plant meet tight outage schedule
A leading Turkish cement producer has specified high- performance air cannons to replace an under-performing existing system, which was jeopardizing the plant’s output capacity by failing to remove accumulated material from the preheaters. The new air cannon network resolves build-up issues that previously needed manual removal on a daily basis, which required at least two hours’ maintenance each time, as well as a monthly slowdown for a major cleaning.
To supply the cement industry in Turkey and other countries, the Izmir Cimentas plant manufactures 5,550 tonnes per day of clinker from two production lines. Located in Izmir’s city centre, the facility is one of the four cement plants belonging to Cementir Holding, acquired in 2001. Cimentas is the first foreign-owned Turkish cement producer, and has a total annual production capacity of 5.4mt (million tonnes). Since 2001 Cementir has invested more than US$530 million to expand capacity and increase efficiency, consolidating and enhancing its presence in Turkey.
To address the material build-up issue, the plant decided to have a detailed survey performed by Martin Engineering technicians, who inspected the preheaters and planned out a solution that included upgrading all air cannons on the entire preheater tower of the 3rd line with Martin Engineering air cannons. On 15 January, 2010, a purchase order was received from Cimentas headquarters of Turkey, with a tentative installation date in mid-March.
However, just three days later, officials from the plant called Martin Engineering Turkey’s office in Istanbul, explaining that the facility now hoped to use an outage of just ten days to install the
air cannons, starting immediately. Martin Engineering Turkey placed a rush on the order,
delivering 50 high-temperature nozzles, 50 air cannons and a variety of pneumatic components and control systems to the plant within a few working days. On the second day of the shutdown, Martin Engineering Service technicians arrived at the plant to begin the upgrade, working through the night until the changes were complete, supervising the installation and helping to program the firing sequences.
The Big Blaster® Air Cannons with Tornado Exhaust valves fire a powerful discharge of compressed air to remove material adhered to the vessel walls. Introduced by Martin Engineering in 1974, the technology has since developed a proven track record around the world for relieving bottlenecks caused by material buildup in high-capacity storage and process vessels.
The air cannon combines a fast-acting, high-flow valve with a pressure vessel (tank). It performs work when compressed air (or some other inert gas) in the tank is suddenly released by the valve and directed through a nozzle, which is strategically positioned in the tower, duct, cyclone or other location. Often installed in a series and precisely sequenced for maximum effect, the network can be timed to best suit individual process conditions or material characteristics.
The timed discharge breaks down material accumulations and opens blocked pathways, allowing solids and/or gases to resume normal flow. In order to customize the air cannon installation to the service environment, specific air blast characteristics can be achieved by manipulating the operating pressure, tank volume, valve design and nozzle shape.
Described as the latest advancement in air cannon valve design, the patent-pending Tornado valve fires in response to an air pressure surge delivered by a solenoid. The design improves air cannon safety, as discharge requires a positive signal. Unlike negative pressure-firing designs, a cannon equipped with the Tornado valve will not discharge accidentally in response to a drop in pressure, so an air supply failure or broken line won’t trigger its firing.
The positive action of the valve also delivers faster discharge, amplifying output force by as much as 20% over standard air cannon designs. The fast- acting valves can release
the tank volume in less than 300 milliseconds, creating a high-magnitude force at the exit nozzle that’s installed through the wall of the vessel or duct. In addition, the improved air path of the Tornado fills the reservoir three to four times faster than standard cannons.
Since the air cannon installation was completed in February, 2010, no manual cleaning has been needed in the entire preheater tower. Plant officials relayed positive references to another Cimentas plant in Turkey, leading to a similar system being
installed at the Cimentas Elazig plant. Martin Engineering supplies conveyor products around the
world in a wide variety of bulk material applications, including cement/clinker, rock/aggregate, coal, biomass, feed pellets, grain and other materials. Founded in 1944, Martin Engineering is a specialist provider, making bulk materials handling cleaner, safer and more productive. The company is headquartered in Neponset, IL, with global reach from operations in Brazil, China, France, Germany, Indonesia, Mexico, South Africa,Turkey, India and the UK.
 
 
Clean loading of fertilizers with DSH
The patented DSH Systems dust suppression hopper allows dry, dusty, granular materials to flow coherently ‘en masse’ so that dangerous dust emissions are virtually eliminated.
A recent installation in the United Kingdom loading lime into rail wagons, demonstrates how using a DSH System can dramatically reduce dust while bulk loading.
DSH Systems produces hoppers for bulk loading of dry goods including fertilizers, grains, stock foods, limes, sugar, salt and so forth.
The award-wining loading system from DSH Systems enables dust-free loading into a range of repositories such as trucks, rail cars, storage heaps barges and ships.
Bulk loading of fertilizers is a very dusty job as the airborne dust envelops working environments, neighbourhoods, plant and machinery and the emissions cause low visibility and dirty, dangerous and very unpleasant working conditions.
The DSH System was invented to provide a much-needed solution and achieves this result without the need for electricity, dust extraction or internal moving parts.
The DSH System offers positive product transfer control, unlike other handling and loading methods which entrain air, resulting in dust particles becoming airborne and leading to expensive problems and environmental and health and safety
issues. The DSH System reduces product wastage, thus increasing profit margins and can also eliminate the need for more expensive dust control methods. The DSH (dust suppression hopper) System is installed under a feed point where it is suspended above the target repository and kept at operating level.
At the point of loading or transferral, air is extruded from the hopper and the fertilizer is concentrated into a moving solid column falling through free air into any target repository while containing the dust fines in the centre of the column.
Extraction is unnecessary, cleaning and disposal costs are reduced and the client receives a fully specified blend as product loss is minimal. Loading is faster, storage tonnages increase, dust explosion risk is mitigated and operations can be enabled closer to urban areas.
A large New Zealand fertilizer company originally operated in a designated industrial area in a rapidly growing city and a Marae (a Maori meeting house) is a neighbour. The company was aware that it couldn’t continue to cause neighbourhood pollution and annoyance.
The company is a responsible member of the community so it searched for an effective solution. It installed one dust suppression hopper and undertook an evaluation with comparison tests. The results proved the benefits, so the company then altered its plant to incorporate several more hoppers on its site load-out. It now has DSH Systems installed in its fertilizer plants throughout New Zealand.
DSH Systems soon realized there was an urgent worldwide need for a simple dust solution.
Before – using a traditional loading spout.
The first hopper to be installed in a fertilizer plant in the USA went to Mosaic Crop Nutrition site in Savage, Minnesota. Lisa Brickey, warehouse manager needed an improved dust control system at her loading facility. An initial DSH hopper installation was quickly increased to five hoppers at her plant and her recommendations to her colleagues has now resulted in other installations at Mosaic Crop Nutrition plants in the USA and South America.
After installation of the first hopper was completed, DSH Systems received a copy of the following comments from Lisa: “We’ve just installed a
new DSH spout at our feed phosphate load out. Wow!! The dust control is amazing! We LOVE it! The spout was developed in New Zealand by an engineer at a fertilizer company. We’ll be taking out some spouts and putting this in. It doesn’t seem to matter how far the product falls, no more dust is created and the tube of product that comes out of the spout is narrower making it easier to load pneumatic trucks.
No electricity, no moving parts, dollar investment, results.... Priceless.” Lisa Brickey, Mosaic Crop Nutrition, Minnesota.