S: Contact area between flattened airbag and floor, namely area between airbag and ship bottom
How to repair the airbag?
For the marine rubber airbag with small damage, as long as no serious aging (surface without cracking and tacky ) all can be repaired. Recommend using heating method, process as below.
1. Clean airbag surface
Rinse airbag with water, make the damaged place (internal and external surface )clean, don’t have sediment, dirt and oil , then dry the surface. When clean the airbag in water, the soaking time should be no more than 10 minutes.
2. Put the Nylon rubber.
Nylon rubber is rubber dipped Nylon cord fabric. The Nylon rubber used for airbag repairing should be the same as the airbag material . ( Our company can supply the Nylon rubber according to the customer request ). The Nylon direction of Nylon rubber should be the same as Nylon direction on the airbag wall . Laying method of Nylon rubber depends on different forms of breakage. The damage form can generally be divided into Longitudinal cracks ( Crack length direction along the airbag extension ). Transverse crack (Cracks along the circumference direction outspread ). Nail hole (Including the shape less than 10cm diameter damage ) .
Operating steps as below:
(1) Mark the scope of repairing area out as the bound of polish area. The repairing scope should extend to the surrounding of the damaged place , don’t ignore the hidden cracks. The extended range depends on the airbag size and damage size. Usually extend 18~26cm larger than the damage place (Picture 6 for your reference).
(2) Polish the damaged surface need to be repaired ,till shows the Nylon fiber, but don’t damage the Nylon fiber.
(3) For the long crack, it has to be sewed with Nylon rubber first, please note that the distance from pinhole to the crack is around 2~3cm , the space between pinhole is around 10cm
(4) Clean the airbag surface need to repaired using gasoline , and waiting for the surface to be dry.
(5) Brush the glue on the surface. The glue is mixed pure rubber with gasoline . The weight proportion of pure rubber and gasoline is 1:5 . When brush the first layer, thinner glue is better ( The weight proportion of pure rubber and gasoline can be 1:8 ). After the first layer become dry, brush the thick glue and wait until it dry.
(6) Seal the crack with the pure rubber strip with 1mm thickness and 1cm wider than the sewed area.
(7) Brush the gasoline and wait until the surface dry.
(8) Regarding longitudinal cracks, put one layer Nylon rubber with width about 10cm vertically on the crack direction. For horizontal cracks and nail hole can go directly to the step 10 . (Picture 7a for your reference).
(9) Brush the gasoline and wait until the surface dry.
(10) Put one layer Nylon rubber parallel to longitudinal direction. The overlapped range around the crack should be 5cm larger and round the four corners. (Picture 7b for your reference).
(11) Brush the gasoline and wait until the surface dry.
(12) Put one layer Nylon rubber obliquely . The Nylon direction should be the same as Nylon direction on the airbag wall . The scope of overlapped should be 1cm larger than last layer and round the four corners. (Picture 7c for your reference).
(13) Brush the gasoline again and wait until the surface dry.
(14) Put one layer Nylon rubber obliquely with symmetric direction of last layer with the same angle. The scope of overlapped should be 1cm larger than last layer and around the four corners. (Picture 7d for your reference). For 4 layers or less than 4 layers airbag with longitudinal cracks, can stop put more Nylon rubber layer and turn to the step 17. For 4 layers airbag with transverse crack and nail eye damage , go on step 15 and 1
(15) Brush the gasoline again and wait until the surface dry.
(16) Put one layer Nylon rubber perpendicularly to longitudinal direction. The scope of overlapped should be 1cm larger than last layer and round the four corners. For airbag less than 5 layers, can stop put more Nylon rubber layer and turn to the step 17. For airbag with 5 layers , repeat the step 9, 10. The scope of overlapped should be 1cm larger than last layer and round the four corners. Then turn to the
step 17. For airbag more than 5 layers, repeat step 11 to 14. Then turn to the step 17.
(17) Brush the gasoline again and wait until the surface dry.
(18) Put one layer pure rubber on the surface.
(19) Compaction the Nylon rubber layers , remove the air from the Nylon rubber layer.
The shipyard can make a working platform as shown on the picture and prepare Jack ,U-steel , steel heating plate, cotton cushion , sandbag,steel plate. The heating steel plate thickness 25mm, Length 0.5m, Width 0.4m, all the four corners and edge should
be smooth. Put the airbag in the center and heat the steel plate ,using the thermometer to check the temperature of the steel plate. When the temperature rise to 150 ±5 degree centigrade, can be put on the cotton cushion and the damaged airbag area , tight the Jack (pressure up to about 0.6MPa) . With steel plate cooling , heating process can be finished (takes about 40 minutes ) . If the damaged place is larger than the heating steel plate, heating the center first, then heat the two side in order. When heat next part, the heating steel plate should overlap 15mm in the position of the last heating place.
Checking if the repaired area is sealing tightly ,don’t allow internal bubble , peeling off layers etc. The new repairing rubber can’t have aging crack, under heated or over heated. Do the pressure test after surface inspection, the testing pressure should be
1.2 times the working pressure.
Warning: The serious damaged airbag after repairing, should reduce the working pressure.
5. Airbag not suitable for repairing.
To ensure the safety, the airbag is not suitable for repairing if there are one of the following situations :
(1) 8 years or longer since the original shipment.
(2) The bursting airbag caused by serious violation of the rules of use and exceed guaranteed safety work pressure.
(3) Seriously damaged airbag, such as horizontal cracks larger than 1/3 of the circumference. Longitudinal cracks longer than 2m or cross damage fracture.
(4) The airbag surface is severely aged, cracked and sticky , Nylon is rotten.
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