The vacuum performance test method of PVC transparent steel wire hose and the analysis of the cause of wrinkle on the surface of the steel wire hose
After PVC transparent steel wire hose is produced, the general manufacturer needs to carry out related vacuum performance testing. This standard refers to the experimental method for the shape change of the inner and outer surface of the hose after the suction hose is evacuated to the specified negative pressure. , There are two test methods, let's take a look together below.
First of all, as far as the length of the test hose is concerned, the minimum length, excluding the end hose joint, should be five times the nominal inner diameter of the hose, or 1 meter long. In terms of these two data, you can Choose the longer one. For some cases where the length is less than 1 meter, you can choose the whole hose or hose assembly. For some hoses with an inner diameter of 80 mm and below, we generally need to lay the hose as flat as possible on a flat surface, and use a metal plug to block one end to prevent air leakage. At this time, a solid ball is inserted into the hose, and then the open end of the hose needs to be connected to a vacuum pump with a vacuum gauge. Within 60 seconds, we need to reduce the internal pressure of the hose to the specified experimental pressure. And keep this value for at least 10 minutes. In the process of maintaining this test pressure, we can also check whether there is a dent on the outside of the transparent steel wire hose. Finally, we need to tilt the test hose so that the inner solid ball can be The entire hose passes inside, and remember to check the hose for other faults.
For some transparent steel wire hoses with a diameter of more than 80 mm, we need to take another measurement method, which needs to be emphasized here. When testing its tightness, we can first install a sealing plug made of transparent material or a transparent sealing plate on one end of the hose, and the other end can be connected to a vacuum pump with a vacuum gauge. Reduce the internal pressure of the hose to the experimental pressure value within seconds, and keep it for at least 10 minutes. During this process, we can use some light sources that meet a certain brightness to check the internal condition of the hose through the transparent plate and check Is there any injection dent on the outside of the hose, or dryness?
Analysis of the causes of wrinkles on the surface of the PVC steel wire hose
PVC steel wire hose sometimes wrinkles in the production process, the main reasons are as follows
1. Uneven temperature of the die. Uneven temperature will cause uneven heating of the production materials. Check the heating ring to ensure that it is evenly nested in the die.
2. The cooling effect is not good. The hose is not sufficiently cooled after production, so it is necessary to lower the temperature of the cooling water to completely cool it.
Third, the traction speed is not appropriate. The traction speed will be fast or slow, which will affect the surface finish, and the traction speed should be adjusted.
Four. Impurities in the materials Impurities in the production raw materials will cause defects on the surface of the hose and wrinkles. The raw materials must be replaced.
5. The temperature of the body and parts is low. If the temperature is too low, the production process will not meet the requirements, which will affect the processing quality. The temperature of the body and parts must be increased.