Dear Sir/Madam, 

Good Morning! 

I am Helena de CNBM. In the last mail, we talked about the quality problems of hydraulic hoses, and how can we avoid them ? The following is our methods: 


1) After we buy raw rubber , in our laboratory, we test the hardness, according to our requirment in Shore A 82-85. Rubber Tensile must be above 12 MPA.

2) After we buy Steel Wire in middlle parts, in our laboratory, we test the tensile, according to our requirment in 2450-2750N.The tensilbe must be in our required tolerance, to assure the working pressure and burst pressure.

3) In our laboratory, we make vulcanization inner tube rubber and outer rubber with steel wire. To check how much adhensive between them, to assure adhension.
Also, we will imitate vulcanization in production to assure rubber vulcanization is under our control.


1) To prepare soft or steel mandril in prevoius day, and dry the mandrill to assure it separate well from inner rubber, but not hurt inner tube.

2) We adjust steel joint machine,in every two days.Every day, we test the steel wire length difference. We requrie, the tolerance must be in XN(7N,8N,9N,10N,11N,12N) standard to assure same length before braiding machine.

3) In braiding machines, when the steel wire less 50 meters, we will throw out to avoid more connections in braiding reinforcement. 

4) In braiding machines, we adjust spider tension 0.5kg higher then standard, to assure braiding cover more compact and in good shape , higher than standard.

5) We use advanced cold feeder extruder, controlled by PLC computer. Cold feeder extruder has more power to extrude rubber inner tube in good shape.

6) After finishing extruding inner tube,we require to make it recovery prevoius shape in normal temperature, at least 4 hours, we begin to put in colding machine in -35C for brading machine.

7) In braiding and spiral machine, we require pitch and steel wire distance in our standard. To assure the steel wire angle in control.


1)After finishing hoses, we test proof pressure in 1.8 times of working pressure on EACH HOSE for one minute.To assure no any leak or defective hoses shipping to our customers. The burst must is 2-4.2 times of working pressure.

After this set of process, our hoses will be deliveried to our customers. If you want to avoid quality problems and find a supplier stable , maybe we can help you.  

Looking forward for your reply!

Address:Floor 17th, No.4 Building, Zhuyu International Commercial Center, No.9, Shouti South Road,Haidian District, Beijing 100048, China
Tel.: 86-10-68796625 Mon-Sun 8:30ato 5:30pm (China Time)
Fax: 86-10-68796655
Skype; cindyxuxy
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