Joint vulcanization is an important process to determine the quality of adhesive tape during installation. In this process, the chemical structure of the rubber changes and improves the physical and mechanical properties. Accurately grasp the technical conditions, is to ensure the joint strength and joint life of the key, vulcanization process of the technical conditions are mainly vulcanization of the three elements, that is, vulcanization temperature, time, pressure. The technical conditions of the vulcanization process are not strictly controlled or improper, which will cause quality defects such as under-sulfur, over-sulfur, delamination, foaming, heavy skin, and belt deviation, which will bring adverse consequences to future operation and maintenance.

1. Joint parameters and operation points

1, joint lap, steel wire rope core tape joint form has one, two, three and four kinds of four, of which the first two are suitable for the number of steel wire rope, small diameter, large gap tape, the latter two are suitable for high and medium strong belt. The choice of joint form should be based on the belt type, belt strength, wire rope number, wire rope diameter, wire rope spacing and many other factors.

Please refer to attached Table 1 for the technical parameters of the conventional joint of the steel wire rope conveyor belt.

Please refer to Appendix E of the MT668-2008 standard for technical requirements of the joint.

In order to improve the vulcanization quality of the joint, ensure that the two ends of the joint are not peeling and not opening, prevent water and impurities from penetrating into the interior of the joint to corrosion the steel wire rope, the groove at the opening line is generally made into a step shape, so as to facilitate the adhesive material and the master tape to firmly stick to ensure the strength and service life of the joint.

   2, vulcanization time, at a certain temperature after a certain time vulcanization, the comprehensive physical and mechanical properties of the rubber material to achieve, service life, the degree of vulcanization at this time is positive vulcanization, vulcanization time is too long (process called sulfur) or too short (process called sulfur), will make the bonding can not meet the performance requirements.

     3, curing temperature, curing temperature can speed up the curing speed, shorten the curing time. If the vulcanization temperature is increased or decreased by 100C, the basic vulcanization time can be shortened by 1/2 or extended by 1 times. The vulcanization temperature is generally 140-1500C, the temperature is too high will damage the core strength or lead to uneven vulcanization inside and outside the tape, too low will take a long time or vulcanization.

  4, vulcanization pressure, the role of pressure is to make the rubber tight and full of the model, in order to improve the adhesion of the wire rope and the tightness of the rubber and the resistance of the joint. It is generally about 1.8MPa, and both sides of the pressure plate should be pressurized at the same time to ensure that the force at the tape joint is balanced. 5, in the selection of tape joints, in general, should ensure to meet the following aspects: (1) the joint strength should meet the requirements, and reach more than 90% of the strength of the tape. (2) The average effective distance of the wire rope should be greater than 0.25 times the diameter of the wire rope. (3) The vulcanization equipment should be able to meet the needs of the vulcanization length, that is, the joint should be vulcanized once. (4) At present, there are two types of joint: diagonal and vertical flat. According to the production practice, we should generally adopt the bevel type.

Second, operation method

The vulcanization of steel wire rope core tape joint mainly includes the following steps: setting vulcanizer (operating platform), cleaning the joint, finding the center, brushing glue, laying glue, swinging rope, laying glue, installing heating plate, fastening, heating, pressing, timing, drawing mold and dressing.

(1) Preparation before operation

1, personnel requirements: before the class familiar with the operating procedures and process requirements, four in one, the Internet guarantee in place, and there are 3 to 5 skilled workers to check the operation.

2, equipment preparation: vulcanizer (electric heating and water-cooled flat type vulcanizer), 660v and 380v AC power supply, supporting vulcanization (automatic/manual) control switch, pressure pump, pressure pump control switch.

3, material preparation: face glue, core glue, glue, 120# gasoline, white cloth, white iron sheet, cushion iron.

4. Tool preparation: 6 cutters, 2 clamp pliers, 2 adjustable wrenches, 4 ratchet torque wrenches, 1 electric wire brush, 4 brush, 1 cleaning brush, 2 wire cutters, 4 stripping pliers, 2 3m steel tape measures, 1 1200mm square, 1 powder box, 6 thermometers, 1 bucket, 2 stainless steel basin, 6 pairs of rubber gloves, 2 scissors, 1 hair dryer, 2 dry powder fire extinguishers, etc.
5, site requirements: flat, wide, clean, no dust, dry air, water, enough lighting.

6, staffing: 10-14 operators, 1 electrician, four in place.

(2) vulcanizer installation:

1, equidistant horizontal stable vulcanizer of the two I-steel bottom beam, placed width is less than the vulcanizer width (if it is inclined vulcanizer, the bottom beam end according to the Angle of the vulcanizer placed each other).

2, the positioning platform at both ends of the bottom beam is fixed on the I-steel bottom beam, and the table should be flat with the vulcanized heating plate or slightly lower than the heating plate surface of about 5mm.

3. The aluminum alloy beam is evenly placed on the bottom beam according to the Angle of the vulcanized plate. Place the water pressure plate on the beam, then place the insulation board on the water pressure plate, and then place the heating plate on the insulation board.

Operating points:

1. When installing the vulcanizer, pay attention to each other to prevent injuries to hands and feet and damage to the equipment.

2. The bottom beam should be placed flat and stable, the vulcanizer heating plate should maintain the same horizontal plane, and the center line is basically the same as the center line of the belt conveyor.

3. Distinguish the upper and lower vulcanization plates to prevent mistakes.

4. The vulcanizer should be surrounded by space for easy operation.

(3) Stripping of the joint:

1. Mark the center line of the tape.

2. Draw the joint line according to the joint form.

3. Cut the conveyor belt edge glue according to the marking size, peel the covering glue and core glue along the edge of the wire rope, and pull out the steel wire successively, paying attention to retaining the core glue of the transition layer.

   (4) Cut the rope and find the center

1. Arrange the two tape joints to be vulcanized neatly on the vulcanization plate

On, according to the required length of the interface, the belt clamp is fixed on the platform at both ends of the vulcanizer.

2, find the center rope, according to the lap method and lap size requirements, lay out on the wire rope

Cut the marks and cut them one by one with wire cutters. Note: The outer two wire ropes should be fully bonded and cut according to the length.

3, after the wire rope cutting is completed, start to find the center line of the belt, three people on both sides of the vulcanizer, two

One person checks both ends, one person checks the middle. First, the two midpoints are found horizontally at the joint of the master belt, and then the powder rope is pulled tight before and after adjusting the belt so that the four midpoints at the end of the two master belts are in the same straight line, and the two master belts are fixed on the positioning platform at both ends of the vulcanizer to prevent the belt from shifting.

Operating points:

1. When intercepting the wire rope, the wire rope should be numbered one by one, carefully checked, and strictly prevented from intercepting.

2. Measure and carefully adjust when looking to prevent the belt from running off.

   (5) Dressing and shaving

1. Trim the wire burrs and excess glue on the wire rope head. When manually pulling the wire rope, the direction of force should be on the same level as the wire rope, and the force should be uniform to prevent the wire rope from twisting and circling. Use electric wire brush to remove the residual glue on the joint ladder surface and hair, pay attention to avoid the occurrence of sassafras shining or burning phenomenon.

2, with two stainless steel basin, one filled with glue and one filled with gasoline, the wire rope and joint groove have been treated with a white cloth soaked in 120# gasoline scrub clean.

3. After the gasoline is volatilized, brush the rope head and groove evenly with a brush dipped in glue, generally brush two to three times. Each time should dry thoroughly before applying the next glue.

Operating points:

1. Take care of each other when trimming the rope head with a tool to prevent scratching yourself or others;

2. When polishing the wire rope, the Angle between the tool and the wire rope should be as small as possible to prevent the tool from damaging the wire rope;

3. It is strictly prohibited to stand in front of the electric wire brush to prevent flying debris from hurting people;

4, in the whole process, it is strictly prohibited to drop water, oil and other dirt on the steel wire rope and the interface slope rubber surface.

  (6) gluing and laminating

1. Select a dry, clean and flat location, expand the lower covering glue and core glue, and clean the surface with gasoline respectively.

2, with a brush dipped in glue evenly brush two to three times, dry. If necessary, use a hair dryer to accelerate air drying.

3. After the glue solvent on the surface of the glue and core glue is evaporated and dried, the two surfaces coated with glue are relatively bonded and set aside. When fitting, the tightness of both sides of the tape should be moderately consistent, the center line should be aligned, and the tape should be fitted from the middle to both sides to facilitate the escape of air from both sides. After fitting, it should be fully rolled to prevent the accumulation of steam bubbles.

4, if it is necessary to increase the transverse reinforcement, clean the transverse reinforcement on both sides of the brush paste, and then fit between the covering glue and the core glue, and the reinforcement size is less than the interface size 30-50mm.

Operating points:

1. If there is water or other dirt on the fitting surface, it can be fitted after removal.

2, if the glue is not dry or rolling is not solid, it will produce bubbles and bulges, resulting in reduced bonding performance and even vulcanization failure.

3. When laminating, the covering glue and core glue should be extended, and there should be no wrinkles, otherwise it is easy to produce bulges and bubbles.

  (7) Spread glue

1. After finishing and gluing, clean the surface of the vulcanization plate, place a 200×0.5 copper or iron sheet at the seam of the heating plate, and then lay the temperature resistant interlining cloth on the vulcanizer heating plate, and then lay the compound gluing flat on the vulcanization plate.

2, according to the joint size requirements cut the surface glue and adhesive core glue, the length should be equal to the distance between the two ends of the joint groove, the width is equal to the width of the original belt. The groove can be hit with hammer or wrench to make it reliably bonded with the composite glue.

3. When cutting, both ends of the core glue should be 20-40mm shorter than the covering glue. Too long, the rubber material will be extruded above the groove of the master tape, making the joint uneven and easy to peel; If it is too short, it will cause insufficient filling of rubber material, insufficient density of joint, and can not reach the required strength, affecting the quality of joint.

4. After the rubber laying is completed, scrub the core rubber surface with gasoline, and then apply the glue twice. After the glue is fully volatilized and dried, begin to swing the rope.

(8) Swing the rope

1. Check whether the center line of the interface is accurate with the white wire rope, and hit the center line on the core glue, and then separate the two connectors from the middle of the wire rope.

2, find the joint center wire rope, according to the selected lapping mode start swinging rope. When arranging the swing rope, the staff should clean their hands or operate with rubber gloves. Swing it from the center to the sides, so it doesn't go wrong.

3. Insert the wire rope into the lap joint alternately, fill between the wire rope and the butt end of the wire rope with vulcanized core rubber strips, and fix the wire rope head firmly. The wire rope must be arranged neatly and straight to avoid incorrect lap bonding. And to straighten each, no concave and convex, bending, no burr head phenomenon, adjacent wire rope spacing to be uniform.

4. At the same time of swinging the rope, the upper covering glue and core glue are cleaned, coated and combined according to the above-mentioned method.

  Operating points:

1, the wire rope on both sides of the edge must be fully bonded. In addition, the outer rope head must be placed along the running direction of the belt, and must not be laid in reverse.

2, the vulcanization face is strictly prohibited from dripping water, oil, ash and other unclean things.

   (9) Cover and cut rubber

1. Fill the outer side of the steel wire rope with covering glue, and then brush the whole rope surface and groove with glue. 2. When the glue is volatilized, the composite core glue and the covering glue are covered on the wire rope. At this time, the tape should also be moderately consistent on both sides, the center line is correct, and the tape is fitted from the middle to both sides to facilitate the escape of air from both sides.

3. After fitting, fully roll to prevent the accumulation of steam bubbles.

4. Cut off the excess gluing material at the groove according to the required size, and cut off the excess glue on both sides of the interface according to the width of the belt. 5, but also use the process knife or awl in the covering glue above to draw or thorn a number of pores, to facilitate the discharge of water vapor, to ensure the quality of vulcanization.

Operating points:

1. Where there is no wire rope on both sides of the interface, fill with rubber material to reach the thickness of the original tape.

2, after cutting the glue, be sure to brush the groove and both sides of the glue.

3, used gasoline and white cloth should be properly placed, not thrown.

4, cover the composite rubber, to prevent the wire rope warping or overlapping.

5. During the whole process above, the vulcanization surface must be kept clean and hygienic, and water or oil dripping on the vulcanization surface is strictly prohibited.

   (10) Clamping plate and fastening

1. Lay a layer of heat-resistant interlining cloth on the covered glue, place a stop iron on both sides, and fix the stop iron clamp belt with a pull rod.

2. Place a sheet iron at the joint of the vulcanized plate, and then place the vulcanized plate and the upper beam in turn.

3. Tighten the tie rod with torque wrench.

   Operating points:

1, check the position of the joint on the vulcanization plate, the vulcanization joint should be in the middle of the vulcanization plate, and there should be a margin around it   

2. Test of concentricity: check the center line again before swinging the rope to ensure that the center line of the two conveyor belts is in the same straight line   

3, if it is a new belt, to identify whether the bearing surface is correct.

Safety points:

1, lift vulcanized plate, beam must pay attention to the safety of personnel;

2, the upper and lower vulcanization plate should be aligned, the number should be consistent;

3. The fastening degree of the tie rod should be uniform and appropriate;

4, to prevent the vulcanization plate lifting ring, fastening screw, other things hinder the water pressure plate water injection hole or vulcanization plate cooling hole pipe connection;

5, it is strictly prohibited to leave any tool or other foreign matter in the vulcanized joint.

   (XI) Sulfuration

1. Check that the vulcanizer is installed correctly and the line is correct. Connect the temperature sensor (with a metal thermometer if necessary).

2, switch on the vulcanizer control switching power supply, start heating vulcanization. At the same time, connect the pressure pump and the water pressure plate pipeline, start the pressure pump and gradually rise to the specified pressure.

3, the general vulcanization pressure is maintained at about 1.8±0.2MPa, the vulcanization temperature is maintained at 145±1℃, and the constant temperature holding time is 45±2 min.

  Operating points:

1, the vulcanization link is key, and it should be strictly implemented according to the specified parameters;  

2, the temperature sensor should correspond to the seat, do not insert the wrong;

3, there must be a special person to continuously observe and monitor whether the vulcanization temperature is uniform and balanced, whether the pressure is balanced and appropriate, whether the vulcanization time is set to meet the requirements, whether the equipment is operating normally, there is no leakage, if the problem is found to deal with quickly, otherwise it will lead to the entire vulcanization failure;

4, when the personnel walk, prevent the temperature sensor line, pressure water pipe, cable, pressure gauge, thermometer, etc., tripping, loose or damaged.

(12) Drawing and trimming                            

1, when the time is over, the vulcanization switch automatically trips.

2. After everything is normal, you can lock the switch and remove the temperature sensor.

3. Connect the cooling water pipe and begin to fill the heating plate with water for cooling.

4, when the temperature drops below 80 ° C, the pressure can be removed, the vulcanization plate is removed, and the vulcanization is finished.

5, after removing the vulcanization plate, check whether the vulcanization quality of the joint meets the requirements, there are no defects, and immediately repair and repair, so that the edge is neat and smooth, no imperfections or excess rubber material. If a bulge is found, prick it immediately with an awl to prevent the bulge from expanding.

   Operating points:

1. After confirming that there is no abnormal situation in the vulcanization process and everything goes smoothly, cooling, pressure relief and mold drawing can be done;

2. When removing the vulcanizer, take care of each other to prevent injury or damage to the equipment;

3, find the problem in time to deal with, shall not be left.

  (13) Tying the bundles

Clean up, debrief, call it a day.

     Operating points:

1. The remaining rubber, gasoline and white cloth shall be recycled into the well in time, and shall not be discarded at will;

2, the vulcanization equipment neatly placed, properly kept, shall not be lost or damaged;

3, carefully check the surrounding environment, do not leave security risks;

4. Explain the work situation of the class and get off work.