LEAKING PIPE JOINTS

Leakage at bolted joints of hot oil and asphalt piping are common problems. Most leakage problems stem from misalignment of the joints when they were originally installed (Fig. 21 and 22). Pipe installers often try to correct misalignment problems by using unusually thick gaskets and over-tightening nuts on the flange bolts. Sometimes they even resort to using two gaskets in an effort to stop a leaking joint. Unfortunately, these unorthodox fixes don’t last very long and the leaking returns after awhile.

If you are experiencing leaking pipe joints, please refer to Heatec Tec-Note: How to prevent leaks in pipe joints at HMA plants.

Figure 21. Flanges properly positioned before bolting.

Figure 22. Flanges have unacceptable alignment.

LADDERS AND HANDRAILS

Ladders and handrails are important safety provisions (Fig. 1). Check them regularly to make sure they are secure and in good condition. Moreover, make sure they are not bent or damaged from contact with other objects. Also make sure they are not weakened from rust, especially at joints where they are welded. None of their bolts, nuts or other parts should be loose or missing.

INSULATION

Periodically check the exterior of asphalt tanks to ensure the skin and insulation are not damaged. Damaged skin may lead to loss of insulation and unnecessary heat loss. Moreover, damaged skin may allow water to soak the insulation resulting in unwanted rusting in addition to heat loss.

Damaged skin and insulation should be repaired with new materials.

CLEAN OUT OF TANK

The interior of asphalt tanks (Fig. 23) may need to be cleaned out after they have been used for a couple of years or more. Although cleaning out a tank may be tedious work, it can definitely be worthwhile.

In normal use asphalt can build up a coating inside the tank. Heavy buildup on heating coils-especially those with fins-can significantly reduce their effectiveness to heat the liquid asphalt. Massive buildups on other interior parts can reduce the usable volume of the tank. And it is not uncommon for built-up materials to form large clumps that can beak loose and block vents or clog pumps.

Cleaning out an asphalt tank requires emptying the tank completely and waiting until it is cold. All of the safety requirements set forth in OSHA regulations should be strictly followed before anyone enters the tank.

Cleaning may require using hammers, chisels, scrapers, wire brushes and shovels. It is not necessary to clean down to bare metal. Just try to get rid of the large pieces and the heavy deposits. Take care not to damage the heating coils when cleaning them. Wear hearing protectors.

Figure 23. When cleaning out a tank, take care not to damage components inside the tank—especially the coils and their fins.