Sealing communication cable with heat shrinkable tube

- Mar 15, 2019-

The sealing operation steps and methods of heat shrinkable sleeve assemblies and heat shrinkable tubes are as follows:

(1) After the connection and testing of the cable, shielded connection wires are installed at the incisions at both ends of the cable and the core wires are wrapped.

(2) Installation of metal lined sleeve (longitudinal package non-inflatable type: pay attention to the pipeline electricity fee zipper above, wall and overhead cable zipper below, small logarithmic cable below large logarithmic cable. Longitudinal pack inflatable type: pay attention to the air nozzle upward, zipper facing the operator, small logarithmic cable and large logarithmic cable level and large logarithmic cable close to the operator.) It is required to wrap all the connecting parts of the cables, overlap the openings at both ends with the cables, and glue and fix the longitudinal splicing seams with aluminum chaff or PVC tape. The splicing seams are 90 degrees with the shrinkage sleeve zipper, and wrap all the ends of the liner sleeve with PVC tape.

(3) Clean the outer sheath of the cables at both ends of the liner bushing (about 200-300 mm in length), and then grind the clean parts of the cables with abrasive strips.

(4) According to the length of the heat shrinkable sleeve, mark the cable 20 mm inward at both ends, wrap the heat insulating aluminum foil around the outside of the mark (around the cable and 40 mm coincidence), and smooth the heat insulating aluminum foil with a blunt tool.

(5) Heating the cable sheath between the metal liner bushing and the insulating aluminium foil with a blowtorch to raise the temperature to about 60 degrees.

Cylindrical heat shrinkage steps:

(6) Move the heat-shrinkable sleeve outside the metal lined sleeve and pinch the heat-shrinkable sleeve to confirm that the metal lined sleeve is located in the middle of the heat-shrinkable sleeve. The branch cables should be fitted with divergent clamps and fixed at 150 mm away from the heat-shrinkable sleeve.

(7) After preheating the whole heat-shrinkable tube with a blowtorch, the heat-shrinkable tube is evenly baked from the middle position to one end in the form of a circle, so that the discoloration disappears until it shrinks completely, and the hot-melt glue with sleeve and dividing clamp overflows and then bakes to the other end until it is all finished.

Longitudinal package pyrocondensation step:

(1) The heat shrinkable sleeve is longitudinally wrapped outside the metal lined sleeve, fitted with connectors and clamps, pinched according to the heat shrinkable sleeve, confirming that the metal lined sleeve is located in the middle part of the heat shrinkable sleeve. (Longitudinal pack inflatable type: the shrinkable sleeve is wrapped on the metal lined gas nozzle as the middle part, and the valve core or the whole valve connecting head are removed.) Branch cables shall be fitted with bifurcation clamps and secured 150 mm away from heat shrinkable sleeves.

(2) After preheating the whole heat-shrinkable pipe with a blowtorch, heating the two sides of the zipper to make it shrink slightly. Then bake the end of the heat-shrinkable pipe in the form of a circle from the middle to the bottom to make it shrink and discolor disappear. Heat it to the shrinkage and fineness of the metal liner sleeve. Apply blunt device to tap the zipper to make it coincide with the shrinkage of the metal liner sleeve. After baking at one end, the tube at the other end is baked from the middle part.

(3) Before the end of the baking, adjust the blowtorch to a small fire, and bake the whole sleeve evenly once again (vertical pack inflatable type: focus on heating around the valve nozzle). Check whether the sleeve has discoloration, whether the hot melt glue of the sleeve at both ends and the hot melt glue of the divergent clamp overflow, otherwise continue baking until completion.

(4) Longitudinally packed inflatable casing shall be installed with valve connector after it has been completely cooled, and the valve core and cap shall be tightened, then the air tightness of the joint shall be checked by inflatability.

Installation procedure of heat-shrinkable valve

The heat-shrinkable valve is used for the maintenance of cable inflatability, and plays the role of connecting the inflatable duct. It should be installed at one end of the inflatable system.

(1) Open air holes on the cable with an electric knife (no damage to the cable core).

(2) Clean the cable with detergent, and then grind the cable 350mm.

(3) According to the length of the heat-shrinkable valve, the aluminum foil is pasted, and the aluminum foil and the heat-shrinkable sleeve coincide and press about 15 mm.

(4) Cover the heat-shrinkable valve and insert the fixing rod (self-made wood, bamboo and metal rod) from the valve nozzle to align the cable stomata to prevent valve displacement during heat-shrinkage.

_The heat-shrinkable valve is heated and baked.

_After cooling, take out the fixing rod, turn on the valve connector, draw out the inflatable pipe, and install it.

Installation steps of plugging casing

Plugging sleeve is used for cable inflation maintenance, which plays the role of sealing the gas in the cable. It should be installed at the end of the cable.

(1) Clean cables (generally around 400-500 mm), according to the length of the blocked sleeve, strip the cable outer protective layer, shielding layer and insulation layer (generally around 150-300 mm), cut off the cable ribbon, so that the core line is in an evacuation state (no damage to the core line).

(2) Connect the shielding wire and wrap the plastic in the opening. The plastic ends overlap over the cable. The two sides overlap with the cable about 20mm. The plastic fold is wrapped around the tape at the overlap of the cable to form a plastic bag with the upper opening and the lower end sealed.

(3) Stir the plugging agent according to the situation (dosage is generally 500 grams and 250 grams), pour the small-sounding liquid into the big-sounding, stirring for more than 2 minutes, until even.

(4) Instantly pour the plugging agent into the plastic package (according to the situation, it is not necessary to pour the plugging agent out at one time, preferably with a small amount of residual), gently pinch the plugging agent at the bottom of the plastic package by hand, so that it penetrates into the inside of the cable, and has no gap with the core cable. If less plugging agent is found, continue to add.

_Wrap the plastic wrap fold outside the bottom plugging agent, wrap 5-6 layers with 100 mm wide plastic tape, and wrap 2-3 layers with horseshoe tape (the thickness is smaller than the diameter of the plugging sleeve).

Grinding and plugging the cables at both ends, pasting aluminium foil, wrapping up the plugging sleeve, baking the sleeve until it is finished.

Grinding and plugging the cables at both ends, pasting aluminium foil, wrapping up the plugging sleeve, baking the sleeve until it is finished.