We checked every lot when production of pvc layflat hose. 2pcs are taken at random from finished hose. Normally, 5FT water hose are cut and assembled hose with coupling. Crimping or banding is up to clients' instruction.
Glue will be brushed on surface of coupling evenly for good sealing and inserting hose easily.
After finishing assembling PVC discharge hose, we will connect them to test bench. Test pressure is 1.5 times of working pressure. Valve will be released to expel air after PVC layflat hose is slowly filled with water.
We will increase test pressure of hose to working pressure within 1 minute. Then, we keep working pressure of PVC layflat hose for 1 minutes. Finally, we raise test pressure to 1.5 times working pressure and maintain 1 minutes.
During test, we will watch hose surface carefully and touch pvc layflat hose by hand to feel wet or not. It is critical to see the coupling whether leak.
Today, we checked two pcs at random. At working pressure, pvc layflat hose was fine. Water leaked from hose end when we raised pressure to 1.5 times working pressure.
We stopped test and dismantled coupling to inspect the inner liner of hose. The inner liner was good. We didn' t find any leaked hole. It was possible that the issue was due to clamp.
We replaced new clamps for pvc layflat hose. However, same issue happened again.
We are very puzzled for the issue. Our quality manager suggested to adjust pressure of assembling machine. We increased pressure of assembling machine to 4 Issue of pvc layflat hose assembly still existed.
Finally, as a rubber hose factory, we changed coupling and tested pvc layflat hose again. We took coupling from another order. The problem was solved.
We were well aware that problem was from coupling. We compared two couplings again. We found the important difference of two couplings.
One hose tail was machined too much. The hose tail was not round now. The gap will appear when test pressure of PVC layflat hose will increase. The water will leak from the gap.
Picture is enclosed in the following:
