As the name suggests, slip on flanges are placed on pipes by sliding them into place. The flanges are then fastened in place by two fillet welds. One fillet weld is executed on the inside and another on the outside of the flange cavity.
The diameter of the slip-on flange is larger than the outer diameter of the pipe on which it is fitted. This makes it easy to slide the flange in place before executing the fillet welds. The slip-on flange does not affect the diameter of the pipe on which it is fitted. This makes it applicable for pipelines that require steady flow. The following are steps to be followed when installing a slip-on flange on a pipe.
Check the Condition of The Slip-On Flange and Pipe
Before installation, one needs to ensure the pipe and the slip on flanges are in perfect condition. This ensures there is do damage on the pipe or flange that might prevent the formation of a proper seal. In some cases, the surface of the pipe might be bent; this leaves a space between the flange and the pipe, which might cause leakages.
Sliding the slip-on flange onto the pipe
After checking the condition of the pipe and flange, the slip-on flange is slid on the pipe to the desired position. In most cases, the flange is slid to the end of the pipe. Such cases are when two different pipes are to be joined in a pipeline.
Fasten the Slip-On Flange in Position
Once the right position of the slip-on flange is established, it has to be fastened onto the pipe. One of the ways in which the flange is fastened is by screwing the flange pins in position to hold the pipe. Once the pins hold the flange in place, the flange slightly tapped using a hammer to ensure its face is flush with the end of the pipe. The most important step in fastening the flange in position is by welding. Two fillet welds are executed on either side of the flange to hold it in position.
The person executing the weld should have adequate experience to produce excellent results. The welds should be strong enough to withstand pressure and vibrations in the pipeline.
Check for The Efficiency of The Slip-On Flange
Once the flange has been fastened in position, pressure and strength checks should be done. If the slip-on flange is fitted on a water pipeline, the tap should be turned one to check to leakages. The tap should be turned on gradually while observing the response of the flange at different pressure levels. If there is a leakage at the fillet welds, they should be removed and the welding process repeated. Leakages that occur between the flanges might be due to the damages gasket. If this happens, the gasket should be replaced.
To check for the strength of the slip-on flange, the water should be left running at maximum pressure for over an hour. If the flange develops no signs of breaking off, it means it is strong enough to withstand the pressure in the pipeline.