Tag Archives: maintenance

Martin Engineering: Conveyor Technology helps Gold Rush Team compete

Neponset (IL), USA – Martin Engineering has supplied belt conveyor technology to 316 Mining Company to maximize the output of their gold mining operations. 316 Mining is well known from “Gold Rush”, the most popular show on the Discovery channel. The show follows the exploits of three competing mining teams as they seek to extract the most placer gold from their operations.

Continue reading Martin Engineering: Conveyor Technology helps Gold Rush Team compete

Martin Engineering: Innovative Air Cannon Positioning at Clinker Cooler for easier Maintenance

Neponset (IL), USAMartin Engineering has helped a U.S. cement plant resolve clogging issues in its clinker cooler, using advanced air cannon technology and an innovative mounting strategy.  HeidelbergCement’s Lehigh-Hanson facility upgraded to modern air cannons and set them in a long U-shaped pipe configuration away from the hottest area of the cooler to offer powerful material flow support with easy maintenance.  The result is a safer workplace, extended equipment life, less downtime and a lower cost of operation.  Continue reading Martin Engineering: Innovative Air Cannon Positioning at Clinker Cooler for easier Maintenance

General Kinematics introduce Barrier Advanced Vibratory Equipment Monitoring

Crystal Lake (IL), USA – General Kinematics has introduced BARRIER™, a vibratory equipment monitoring solution that includes three components:  APEX™, VERTEX™ and NOMADX™. Barrier provides three levels of equipment tracking that can be customized to the user’s process to better maintain their equipment and avoid downtime. Continue reading General Kinematics introduce Barrier Advanced Vibratory Equipment Monitoring

Flexco TUG HD Belt Clamp simplifies Maintenance Work on Conveyor Belts

Rosenfeld, Germany – When a conveyor belt is stopped for maintenance, say in a coal mine, its own weight can create problems by distributing the tension unevenly. To ensure that a belt can be safely cut and securely spliced by service technicians, the forces in the area under repair should be spread over the whole width. For this purpose Flexco has developed the TUG HD belt clamp. It is suitable for a variety of materials and belt types – and meets rigorous industry standards. Continue reading Flexco TUG HD Belt Clamp simplifies Maintenance Work on Conveyor Belts

Heyl & Patterson: Thrust Roller Maintenance – Rolling into 2016

Happy New Year! As we head into a new year many of us resolve to be less stressed, more efficient and in the best shape of our lives. Those same resolutions can often be applied to capital equipment.  So while you are setting those goals to improve your well-being in 2016, let us review the ways we can improve the life of our equipment. A few simple preventative maintenance items can make 2016 your continuous barge unloader’s best year yet.

Proper equipment maintenance is crucial in extending the useful life of any machine. For a continuous barge unloader the maintenance of trolley thrust rollers is paramount to efficient function. Without properly adjusted thrust rollers installed weight is redistributed to other components that are simply not designed to handle them. Thrust rollers are necessary to bare heavy loads.



Issues involving trunnion equalizers, rail or wheel flanges are often the result of poorly maintained thrust rollers.  Thrust rollers must be properly maintained to avoid a snowball effect of malfunction.

Regularly completing a visual inspection of the thrust roller can help to avoid long term damage. Be on the lookout for any side to side motion which would be a telltale sign that there is an issue.


It is of utmost importance that the rollers be lubricated regularly. Depending on the machine’s usage level this may be once week, up to daily for machines that run 24/7.

Maintaining the integrity of the trolley thrust roller will prevent wear on the flanges of the trolley wheels, wear on the side of the main vertical rail head as well as excessive stress on the trunnion equalizer wheel frames.



Basic maintenance will help prolong the life of rails, trunnions, wheels and ultimately the life of the continuous barge unloaders.

H&P offers and strongly recommends comprehensive inspections for all continuous barge unloaders. As the Original Equipment Manufacturer, no one understands the machine better or is more qualified than Heyl & Patterson to determine the condition and expected operating life.

In addition to this capital equipment, Heyl & Patterson is also a trusted partner after the sale, to cover the complete operational life of customers’ machines.  This wide range of services also includes replacement parts and upgrades whether the equipment was purchased from our company or another manufacturer, as well as inspections to maintain operation at peak performance and field service to help extend a machine’s life.  Additional literature in the green-branded Bulk Transfer Division line includes CBU UpgradesRailcar Dumping SystemsHammermillsDumper Upgrades and Railcar Movers.

For more information on Heyl & Patterson’s Barge Unloaders, click here

Heyl & Patterson Celebrates 125 Years in Business

Heyl & Patterson Videos on bulk-online

Mac + AccuRate = Schenck Process


Reports on “Parts and Services”

Baghouse Services Utilize 40 Years of Experience

With over 40 years of dust collection experience, our Baghouse Service Program helps customers lower emissions and meet EPA standards. Experienced technicians and trained crews handle inspections, bag changes, repairs, installations both new & used, flow studies, conversions and more for any size dust collector or brand.
Benefits of Baghouse Service Program:
Extended life of bags

  • Lower emissions
  • Reduced downtime
  • Reduced in-house maintenance costs
  • Improved plant sanitation and employee satisfaction
  • Minimized plant liability
  • Reduced operational costs
  • Reduced spare parts inventory

Tech Tips:
Monitoring the Differential Pressure of Your Baghouse
Tips from Schenck Process Service Technicians to ensure your equipment continues to run accurately and efficiently.

  • The differential pressure reading is a simple way to get a quick assessment of how your baghouse is running. It is important to monitor the pressure differential of your baghouse on a regular basis (at least once a day), and make sure the pressure differential gauge is working correctly.
  • If there are any sudden changes in the pressure differential, whether up or down, first make sure the two lines connecting the gauge are not plugged, crimped or damaged.
  • If the gauge is reading “normal” range, and there are no emissions visible, the filter is running properly. If, however, you begin to notice an upward creep in the pressure differential, it can be an indication that the filter bags are beginning to plug and may need to be replaced.
  • If there is sudden upward spike in pressure differential, it is usually symptomatic of an upset condition in the baghouse (for example, a sudden influx of moisture-laden air that decreases bag permeability) or possible problems with the bag-cleaning system.
  • If there is a sudden decrease in pressure differential, often accompanied by visible emissions, may indicate actual failure of one or more filter bags.
  • If you have any questions please contact our Baghouse Service group at 800-821-2476.

Schenck Process Crossword Puzzle
Test Your Material Handling Knowledge
Complete this puzzle and send it to mktg@schenckprocess.com for your chance to win a $100 VISA gift card. Winner will be determined by the most correct answers. In case of a tie a drawing will be held to determine a winner.

Tech Tips:MECHATRON Feeders
Tips from Schenck Process Service Technicians to ensure your equipment continues to run accurately and efficiently.

  • Make sure your flex hopper clamp is above the guide pin on the front of the hopper. This ensures material will never leak from the flex hopper connection.
  • Do not use any chlorine based cleaners on the flexible hopper. If you have questions check with the Schenck Process Service department to make sure you’re cleaner is approved.
  • Make sure your inlet and discharge connections always have a little bit of slack. A feeder on load cells should be “floating.”
  • If in gravimetric mode make sure the feeder remains untouched. Bumping or resting on the feeder while its running can greatly influence the load cells and flow rate.
  • If changing to a new material, contact the Schenck Process Service department to help verify your helix is capable of your required rates.
  • If you have any questions please contact our Technical Service group at 888-742-1249 x3.


Repair Program Extends Product Life
The Schenck Process Equipment Repair Program helps customer minimize costs, and avoid downtime. Repair work can be done on a wide range of equipment, for both Schenck AccuRate and Mac Process product lines.
Our Whitewater, WI Repair Center offers repairs on Schenck Process weighing and feeding equipment such as: feeders and weighfeeders, load cell modules, counterbalance scales, platform scales, mass flow meters, IDMS valves, iris valves, and controls. Schenck Process service personnel are available for on and off-site repairs and equipment exchange during times of repair. When available, refurbished equipment can be exchanged or rented during times of repair, reducing plant downtime.


The Valve Rebuild Center located in Sabetha, KS, restores airlocks and vales to peak performance. Services offered include: re-machining of castings, replacement of components (seals, o-rings, package bearings, and shaft blades), sandblasting, painting, re-anodizing, and new actuator packages. Schenck Process technicians will conduct a full inspection of equipment and will send a detailed estimate. Refurbished valves are returned in like-new condition and come with a 1 year warranty.

About Schenck Process
The name Schenck Process is synonymous with more than 125 years of experience and is a strong brand. Originally founded as an iron foundry and weighing machine factory, it has grown to become one of the global market leaders in applied measuring and process technology. In 22 countries on five continents, more than 3,200 employees are developing innovative solutions for weighing, feeding, conveying, screening, automation and air filtration technology processes. The members of the Schenck Process Group are: Schenck Process, Schenck AccuRate, Stock, Redler, Fairfield, Screenex, Pentec, Clyde Process and Mac Process.


Coperion K-Tron at Fakuma 2014

Coperion K-Tron cordially invites you to attend Fakuma 2014, Oct 14-18, 2014 in Friedrichshafen, Germany, Booth 6406, Hall A6 to learn more about the latest advances in feeding, weighing and pneumatic conveying solutions.

We will show you the patented BSP-135 Bulk Solids PumpTM Feeder on pivoting base frame which has been specially designed and engineered to provide gentle, precise feeding of free-flowing pellets, granules, and friable bulk materials.

Additionally on display will be a Gravimetric Batch Blender with integrated 2400 Series Vacuum Receivers and a Twin Screw Powder Feeder.

Stop by the booth and explore our innovative solutions.

We look forward to seeing you at Fakuma 2014!

Your team of Coperion K-Tron

Bulk Solids PumpTM for precise feeding of free flowing bulk materials

First in the Industry: Positive Displacement Feeding Technology


The new Coperion K-Tron Bulk Solids Pump (BSP) feeders have been specifically designed and engineered to provide gentle, precise feeding of free-flowing materials

The Features

Coperion K-Tron Bulk Solids Pump (BSP) feeders have been specifically designed and engineered to provide gentle, precise feeding of free-flowing pellets, granules, and friable products.

Preview animations and video

The BSP feeders do not use the usual screws/augers, belts or vibratory trays to convey the material. The feeder utilizes positive displacement action to feed free flowing materials with astounding accuracy, offering uniform discharge, consistent volume and gentle handling.

The BSP feeders have vertical rotating discs that create a product lock-up zone, conveying the material smoothly from storage hopper to discharge outlet, achieving true linear mass flow.

Utilizing a simple design and the principle known as “lock up” (see demonstration), the material in the feeder is moved together in true positive displacement, producing excellent linearity and breakthrough accuracy levels.

With no pockets or screws and only one moving part, the compact feeder is cleaned in seconds, making it ideal for applications with frequent material changes.


Download the BSP brochure

Bulk Solids Pump Feeders:
Brochure highlights the features, principle of operation and anatomy of the Coperion K-Tron Bulk Solids Pump feeder line, including information on “Positive Displacement Feeding”, as well as information on various feed rates / models available.
picture of the 4 zones of a Bulk Solids Pump feeder

The Principle

Interparticle forces produce lock-up at the end of Zone 1


Material is in lock-up condition throughout Zone 2 and rotates as a solid body


Interparticle forces fall below lock-up threshold


Material discharge occurs.


BSP technology demonstrations and video

The Anatomy of the BSP-100 and BSP-135

exploded view of BSP-100 and BSP-135



The BSP-100 features a single feeding duct formed by two rotating discs. It includes a conical inlet transition piece which can be combined with a variety of standard extension hoppers.

A slide gate on the inlet allows for material shut-off and removal of feeder for cleaning and hopper emptying. A low power stepper motor drive mechanism and controller provide excellent turndown and flexibility ensuring a very wide operating range.


The BSP-100 is designed for feed rates of 2 to 400 dm³/hr (0.07 to 14 ft³/hr). It is available as a volumetric unit or as a gravimetric unit with a choice of 2 platform scales, single point suspension scale or three-point suspension scale.



The BSP-135 is a slightly larger version of the BSP-100, with all the same features except that it has three feeding ducts instead of one.

The BSP-135 is designed for feed rates of 22 to 4,400 dm³/hr (0.8 to 155  ft³/hr).

Unit is available as volumetric or as gravimetric, with a choice of platform scale, single-point suspension scale, or three-point suspension scale.



BSP-150-S is designed with four feeding ducts, and is based on the same technology as the BSP-100, but manufactured of stainless steel.

The unit is designed with an inlet transisiotn piece, as well as a stepper motor and removable material discharge chute.

With only one moving part and no pockets or screws, the design provides ease of use and almost zero maintenance.

The BSP-150-S is designed for feed rates of 34 to 6,700 dm³/hr (1.2 to 237 ft³/hr).

It is available as a volumetric unit or as a gravimetric unit with a three-point suspension scale.



Benefits of the Revolutionary BSP Technology

  • True Positive Displacement Action
  • Linear Over Full Operating Range
  • Uniformity of Discharge
  • Active Discharge (minimal residual material)
  • Unaffected by Differential Pressures
  • Mechanical & Maintenance Simplicity

For video, animated demonstrations, brochures and technical articles click here.


Gravimetric Batch Blenders

Coperion K-Tron Gravimetric Batch Blenders are available in various sizes from 0.5 kg to 25 kg total batch size and include up to 8 main feed elements depending on the unit.


Each one of the materials is dispensed sequentially into a common weighing hopper in the desired proportions. The weighed materials are then released into a separate mixing chamber, which provides a consistent homogeneous blend. It includes an advanced metering and weighing system that accurately controls every ingredient of every batch to the desired amounts and is not averaged over multiple batches.

Gravimetric Batch Blenders Design Features

The Coperion K-Tron range of blenders are compact with a robust design. They are designed and constructed of heavy gauge steel (11 gauge steel) to withstand the most rigorous of operating conditions. The load cell is overload protected and guarded from physical damage. Each blender is constructed with high load bearing continuous welding and is protected against vibration and shocks. All blenders include self-optimizing software to give you the most efficient output on every recipe. Continuous mixing of the bulk materials means the mixing times do not need to be adjusted and the consistency of every mix is guaranteed.

Standard Mechanical Specifications

  • Ingredient accuracy of +/- 0.02% per batch at highest accuracy setting
  • Robust design (11 gauge steel)
  • Color touch screen
  • 3 level password security
  • Ethernet port with remote service capability
  • 2 USB ports
  • Integrated loading platform for mounting material loaders/vacuum receivers
  • Simple quick drain models
  • Integrated slide valves on each material hopper
  • Side feeders – up to (4) available on most models


For more information on Coperion K-Tron, please click here.

For more information on Coperion, please click here.

bulk-online Leader, Mechanical Feeders, Agitated Feeders, Dosing Feeders, Gravimetric Feeders, Loss-in-Weight Feeders, Proportioning Feeders, Sanitary Feeder, Screw Feeders, Vibratory Feeders, Volumetric Feeder, Weigh Belt Feeders, Pneumatic Conveyors, Modes of Pneumatic Conveying, Dilute Phase Conveying, Vacuum Conveying, Process Automation, Silo Storage Equipment & Systems, Silo Discharge Equipment, Live Bottom Flow Devices, Pneumatic Flow Devices, Weighing & Proportioning Equipment, Weigh Feeders, K-Tron Feeders: Volumetric & gravimetric feeders, K-Tron Premier: pneumatic conveying equipment


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Coperion K-Tron is a  bulk-online Leader

Why does my corporation not give me the funds to improve my plant? Kick your budget requests up a notch

Fishing for capital equipment money every year and going home empty handed is the typical thing happening to maintenance and operation managers every year. Even the support of the plant manager will often not help getting anywhere with your requisition request. Plenty of money will be saved in the long run. Lower energy bills and a much lesser maintenance budget should surely look good to the financial folks.  Well, you are so wrong (usually).

Problem is that in the big scheme of things top level managers and chief financial officers will not give you a Cent because operations are not affected enough and there is not a super short return on investment to entice them giving you the money. Often enough it is actually your ROI (Return on investment) logic and how you structured and formatted it that will make sure that your request will gather dust at HQ (Headquarters).  Then again it can also be the information you did not include. How about the info you included, but jut not in a format top level manager would appreciate?

The list below is just a few ideas how to turn a typical capital investment request into a rocking one with a kick-behind ROI.

  • Let the manufacturer of the equipment help you put an ROI together.  Do not forget speaking with the one whose equipment you want to replace involved too.  For one you never know if they have something better themselves, and on the other hand, they will also be the ones who should give you the latest overhaul and repair prices.
  • Make sure you have you repair and maintenance records straight.  Do you have all the numbers for how much maintenance and operations (lubricant cost, cooling water, and yes, also energy consumption) have cost you?  Do you know what your going energy cost (demand and $/KWh) is?
  • Do you intend to replace heavy oil leaking equipment?  Did you capture how much kitty litter or oil dry you are using now?  How many times does a crew need to walk by the machines checking and topping oil off?
  • How many air filter changes and how much do the filters cost?
  • How much cooling water is needed and how much does it save you getting rid of your old equipment?
  • Can you put an energy audit together?  Get all your own and vendor resources organized collecting data about your air, water, lubricant usages and the required man power that it takes to do all of the above.

Now that you have the basic information gathered you can focus on getting your budget calculated.  The rest is up to the process you use getting your money approved.  The bullet list above deals with the mere mechanics of getting to a basic ROI.  Below is how you can kick your project up a notch and thus you increase your chances to getting financial approval.

  • Replacing a piece of equipment is not a simple tear the old out and put the new in scenario.  Do you have the cost for removal and new installation gathered?  Great.  How about the system integration cost from a controls point?  Did your controls group contribute to your ROI?  Same with operations.  How will operations be affected during the change out?  How easy or tough is will this be to install and start the new equipment?  Hopefully this cost will be low, but did you consider putting this into your ROI?
  • Will the old stuff represent a health or environmental hazard?  How much scrap value is there?  Would sister companies or others want to have this equipment and how much value would this represent?
  • Do not laugh about this one:  How many new or refurbished pieces of equipment do you still have in your company (your own plant and system wide)?  Chances are if you have any left, you will not stand a chance replacing it and the system it is installed in.  It represents a clap trap:  If you do not have any and your production is down it may cost you dearly replacing it in a hurry and the manufacturer of the new stuff may not be able to get you a one to two week delivery.  Planning and risk management is everything with this one.  Look forward too.  Is the current machine still in production?  Does the manufacturer intend to make it obsolete soon?  What have you heard about this from your industry specialists?
  • How much money can be saved with this new piece of equipment if it uses lubricants that you already have in the plant?  Does the new one eliminate routine tasks or stretch out the schedule?
  • Does your equipment run 24/7 or at least 2500 hours per year?  If so, are you using premium efficient motors?  You should!  Calculate the savings with this helpful program called Motor Master.  Note:  Make sure that you have included money for the new motor starter or heaters as the premium efficient motor will have a greater inrush current.
  • Can your new piece of equipment eliminate power demand spikes during starts?  Do they have unloading devices (here is one for blowers)?  Demand charges
    is something few people know about.  Your power bill always has a demand charge and the money per KWh charge.  Did you know that sometimes your demand charge is higher than the other?  Demand comprises the total KW’s (or better the resulting amperage load) that the power company needs to have available for your system not to overload and go off line.  This means that all motors could come on line at the same time.  This means that your charges are based on a much higher demand than what your normal operation load is.  Problem here are the significant spikes at time of equipment start up that are particular bad when you cannot start your motor under no load.  Something to consider and explore with your financial people.
  • Compressed air systems are THE power hog of most plants.  Here is a helpful tool (Air master) in studying your energy consumption and different technologies and manufacturers.  Perhaps why you did not get money in recent requisitions is because you did not fix the more basic problem:  Air leaks.  Do the basics first and then ask for more money for capital improvements.
  • Does the manufacturer offer a remote monitoring system that helps you get off a time based maintenance schedule and instead provides an “as needed” maintenance schedule?  Here is an example for one that alerts you when the machine is in need of attention soon:  Remote.  Experts fix what needs fixing.  Here the machine literally tells you when it needs attention all the way to including vibration and oil level with web based and smart phone accessibility.  It can save you thousands of Dollars annually as such a maintenance system is based on the expert – manufacturer – point of view.
  • The political part is often the trickiest and the most overlooked part of equipment requisitions and ROIs.  Gathering and getting support from your key stake holders is immensely important or you will never get your money into the budget.  That you need to have a solid case made in your ROI goes without saying.  Did you get you plant manager’s support though?  How about your electrical, maintenance, shift, operations, union managers and spokes persons?  How good is your relationship with HQ?  You do not have one?  Well, get to it and get yourself known there for solid work and build your reputation as a cost saver and sustainability improver.

Surely you have realized that this never easy, nor quick to getting your improvements documented and approved.  Some aspects are cut and dry.  The pure mechanics of it all is often what occupies your mind most and yet, the process of getting the stake holder’s support and illuminating the whole system around the piece of equipment is actually almost more important.  Good luck with your journey and make sure to use all the resources that exist around and within you.  Otherwise you will still only be like a lonely angler putting out the line into the big pond of budgets and come home with nothing on your hook.

Ralf Weiser


Time is money: Another case of pay-me-now-or-pay-me-later

This one is for you Mr. Plant Manager or CEO.? Especially if your company is publicly traded company you are very familiar with how tight money appears to be when it comes to funding projects that involve machinery and condition monitoring, which do not have a ? to a 1 year ROI it is virtually impossible to bring them alive.? I have seen projects not make it even though they would have saved the company tenths of thousands of Dollars in power savings, cooling water elimination, repair reduction etc.  You also know that little expense is spared when production is down because a machine broke that sometimes does not even need to have been a critical piece of equipment.? Bunches of money are then spent trying to expedite the repair or replacement.? Ironic, is it not?

I have lost track of how many maintenance managers I have spoken to that wanted to buy a much more reliable and efficient machine that had an average ROI of around 2 years in most cases.? Much like local anglers the manager is casted his line out into the big yearly budget pond in hope that his request would finally be granted.? Yet he gets few nibbles? and thus he is reduced to repeating the same spiel in the following year.?

Now I am not saying that every project is worth pursuing, however, I would implore plant managers and CFOs to look twice before sending your maintenance managers back to the pond:? The money that they could be saving you over time would pay great dividends in less than 2 years.  Imagine what you could do with that money then!? You would need to have faith and not get tied up in the 90 day turn thinking for a little while.? Or you could kick it up a notch and let your CFO run the number that you are currently spending in unnecessary downtime and repairs.? Do not trust existing numbers.? Go speak with you maintenance people that do the actual work and see if your impression now matched what your balance sheet is trying to tell you.? Do not be surprised finding out that your company has become complacent by accepting the current state of affairs as something that cannot change.? If you still cannot go through with the project it may be time sharing this blog with the main company board.? They also should go out and walk the plant floor sometime soon and see what short term thinking does to their folks, morale and most of all their cherished profits.? Perhaps the maintenance managers can finally go home with a big catch from the pond.?

Have an awesome day,

Ralf Weiser

Leaky Blower Safety Relief Valves in Pneumatic Conveying Systems

Do you have money to burn?? Of course not, yet chances are that you are doing just that within your pneumatic conveying system.? Have you ever noticed the hissing sound of such valves when you tour your plant? If so, you are wasting electric energy and maybe risking future maintenance issues.? I cannot tell you how many cement and food processing facilities I have been to, where not at least some valves leaked severely.? You may think the cause is the valve itself. Think again:? Most likely it is your system that does not need all the air and hence is blowing it off through the valve.? The fix is not necessarily a new valve, but either a new belt drive or motor speed slow-down by means of a variable speed drive.

You do not need to be a blower expert to be able to troubleshoot this issue.? Ask your plant operators and production personnel if any product quality or process problems exist in the area you are reviewing.? Guess what, you can turn down the blower speed, if your valves blow off air from conveying (or aeration) systems that are working fine.?The problem assessment step is the most important one; you can leave it to your system OEM, or the blower manufacturer to help you figure out how much to turn down the speed.

Recently?I was invited to review a 75HP vacuum blower system that we were able to slow down by 20%.? Based on 24/7 operating service and the local electricity rate the customer was able to save over $7,000 per package – they had a total of 8 (!).? This is not only more money in your pocket, but it is also easier on the blowers and drives.  Besides of increasing the total service life, this measure also helps reduce the overall CO2 envelope of your plant – you can help the environment by using less energy.

Especially positive pressure relief valve create another issue in plant areas where blowers are installed in building or sound enclosures:? The hot air escaping the valves literally super heats the area around the blowers.? This tends to cause long term reliability issues as the hotter than normal blower intake air lets the machine run even hotter.? Lube oil viscosity decreases, which can cause premature bearing failures.? And it usually reduces the oil service life too (mineral oil in particular).? Elastomeric (rubber) blower shaft seals tend to harden, which can cause oil leaks:? Catastrophic failures follow quickly.? I am sure you get the idea, it is even more money in your company’s budget.

Ralf Weiser