| |
|
|
BOLTING OVERVIEW
In nearly every heavy industrial application, turning threaded fasteners - nuts and bolts - is generally viewed by two criteria:
1.The need to fasten tightly enough to prevent movement of parts and achieve a good seal without exceeding the fastener's elasticity level, and
2.Successful removal of fasteners after long periods of environmental exposure to harsh conditions.
When installing heavy-duty fasteners, there are times when a little more power is required, or in other instances, a lot more power. After all, when it comes to turning nuts and bolts, especially stubborn corroded ones, what could be more basic than power?
The seemingly apparent answer to that question can be profoundly consequential: You need controlled power. That is, controlled "torque." Otherwise, you could outdo yourself and strip threads, break boltheads or even cause personal injury.
Current practice working with heavy-duty threaded fasteners in Nigeria have aimed at sheer torque power, using long lever arms and heavy hammers on slugging wrenches. Most of the foreign oil majors and servicing companies in Nigeria apply torque power with a complete range of torque control products, including manual and powered hydraulic/pneumatic torque wrenches in other countries which they operate, but their operating mode in Nigeria is quite different. These companies utilize long lever arms and heavy hammers on slugging wrenches that have proven to be very slow, inaccurate, inefficient and mostly unsafe in their operations in Nigeria.
The underlying problem with this mode of operation is facility reliability and uptime. The solution is to find ways to eliminate unscheduled equipment downtime. The problem with downtime is that most maintenance people think, "It just happens. Then we fix it." The problem with downtime is, "You can monitor it, measure it, log it, report it, track it, attack it, or delegate it, but downtime will not go away until you "eliminate it" - prevent it from happening in the first place.
Facility installation and maintenance are critical components for a company to deliver capacity and quality. To compete in today's global economy and to increase profits, many companies are moving to "Critical Bolt Torquing" the next step beyond "Just In Time." When critical machines go down for a "maintenance break, the critical questions to ask are:
>How were the fasteners torqued?
>In what order were fasteners tightened?
>What is the best way to verify the torque on fasteners?
>How does torque value vary over time?
THE RIGHT KIND OF EQUIPMENT
The tension joint, however, relies on the tension of the bolt to hold two joined parts together. The greater the tension on the bolt, the more force holding them together. Steel and most metals have a property known as fatigue, which means that they lose strength upon repeated loads. Most joints are subject to variations in load that either adds or decreases the tension in the bolt. A bolt in a tension joint will fail from fatigue if it is not tightened enough, and it will fail from fatigue and overload, if it is tightened beyond its ultimate strength. It is extremely important that we achieve the proper tension on the bolt-not too much and not too little.
The need to get the correct tension is why torque wrenches are used. What do torque wrenches have to do with tightening fasteners? We know that if a bolted joint is not tightened enough it may come apart, or it can break from being too tight. It can even break from being too loose. Torque wrenches help overcome some lack of knowledge and experience but only if they are properly used.
The utilization of hydraulic/pneumatic bolting equipment allows for a safer and faster means of the breakout of large or frozen bolts as well as highly accurate means of tightening those same bolts. From less that one inch-ounce to more than 100 thousand foot-pounds, these torque control tools provide torque, making it easier and often safer to assemble and service-threaded fasteners while reducing application problems and tool costs. When the importance of ensuring the integrity of the bolts, seals, flanges, and process equipment is being considered, Hydraulic/pneumatic bolting equipment can help realize a huge potential savings in manpower and equipment cost. The advantages will be especially beneficial in heavy-duty torque fastening applications for facility installation and maintenance in Nigeria.
|
|
| |
|
ACCURACY
Proper tightening is very important and torque wrenches continue to be the most accurate device, and substantially more accurate than the judgment of even the most experienced mechanic. A good mechanic should have a sense of how a joint should feel when it is being tightened, and should use that information in conjunction with a torque wrench.
Because of the inaccuracies between torque and tension, many users conclude that the solution is to buy a more accurate torque wrench. The significant difference is really not between quality torque wrenches but between the torque/tension relationships, which has at least a 20% range of variation. A good torque wrench might have an accuracy range of 4% or, perhaps, 8% but the TORCUP TORQUE WRENCHES have an accuracy of 3%.
|
|
| |
|
SAFETY/TIME ISSUES
Proper torque application is also vital for worker comfort, productivity and safety, including the avoidance of 'repetitive use' problems. The maintenance person must have and use the correct tools in order to do the work quickly, accurately, and safely. Using the right tool for the right job is a big boost in worker efficiency and safety.
In some instances, the effort required to set up and tighten fasteners can put operators at risk due to fatigue and resulting tool slippage. Safety, getting the job done and costs are all very important-but in just that order. Shortcuts, substitutions and the use of cheater bars are not worth the risks involved. The cost of the hydraulic/pneumatic torque tools is far less expensive than the cost of an accident and the accompanying pain and delays.
For instance, a bolting application for a BOP installation involves a difficult connection due to the interference of the surrounding structure and the requirement for 460 ft. lbs. of torque on the bolts. If done by hand, it will take two employees with breaker bars, manual torque multipliers, and wooden blocks to brace it all up. Now we use a pneumatic torque tool, which is much faster and safer. The HYDRAULIC TORCUP WRENCH is much more convenient. It weighs about 40 lbs., and one man can carry it easily.
Everyone should appreciate the significance of the safety and choosing the correct tool for the application, not only in terms of saving lives and injuries, but the high associated costs.
TIME
With a conventional wrench, properly torquing the hubs on some BOP preventers used to take about three (3) hours but with the Torcup Hydraulic and pneumatic torque wrenches, it can get it done in 30 to 40 minutes. In the oil and gas industry, any time you can speed up an operation and still do it right, that's what we are looking for.
|
|
|
|
|
|
|
|
