JUBILEE PIPE PATCH

The jubilee pipe patch (fig. 7-22) is a modification of a commercial hose clamp. Periodically, you may purchase heavy-duty jubilee pipe patches through the supply system. However, if you cannot purchase them, you can manufacture them yourself.

To manufacture a jubilee pipe patch, roll a piece of sheet metal into a cylinder. Bend a tab on each edge to form a flange. The flanges maybe reinforced by welding on strips of scrap iron. Drill three to five holes through both flanges for the securing bolts. To keep the flange faces somewhat parallel when under pressure, weld small braces from the flanges to the back of the patch.

Use a thick gage sheet metal that will withstand pressure but can also be sprung open enough to be put over the pipe. To use the jubilee pipe patch, put a piece of rubber or gasket material over the hole. It should be large enough to cover and overlap the damage at least 2 inches on all sides. Slip the jubilee pipe patch over the rubber or gasket material. Insert the bolts into the holes and secure them in place. The jubilee pipe patch can withstand 100 pounds of pressure.

SOFT PATCH

Small holes or cracks in low-pressure (150 psi) piping can often be repaired by applying a soft patch (fig. 7-23). When it is possible, reduce the area of the hole first by driving in softwood plugs and wedges as necessary. Do not drive the plugs and wedges in too far or else they will retard the flow of the fluids in the pipe. Once the plugs and wedges are in place, trim them off flush with the outside surface of the pipe. Cover the damaged area with a piece of rubber that will completely cover and extend about 2 inches past the damaged area on all sides. Use two tightly wound layers of marlin or wire to hold the rubber in place.

The soft patch can be modified or improved to suit the conditions at hand. Often it is advisable to use a curved piece of lightweight sheet metal between the rubber and the marline or wire. A coat of red lead on the face of the rubber will also help. You can also use marlin and oakum as a caulking material in the cracks. The soft patch

Figure 7-23.-Soft patch on a low-pressure pipe line. 7-19

can withstand 150 psi. For some types of damage, such as sharp bends in the piping, a soft patch will not be effective. In such cases, you would use a metallic pipe patch instead of the soft patch or jubilee pipe patch.