Common problems and causes of stainless steel thick film heating tube components
1. The incoming material has poor pressure resistance. At present, some of the new thick film heating tube suppliers on the market are prone to this problem. The possible reasons are that the number of printed layers or printing thickness of the insulating layer on the stainless steel tube is insufficient, or the glass powder specification of the dielectric paste is too low, which causes the dielectric sintering ability to fail to meet the standard. For example, the heating pipe produced by the medium slurry of a slurry factory in Hunan has experienced problems with insulation capacity NG, which led to batch returns.
2. Abnormal take-off of temperature control is relatively rare. It is generally manifested as abnormal take-off of the temperature controller during testing or use of the whole machine, but it will not reappear after resetting the manual temperature controller. There is a certain probability that there is a local hot spot in the thick-film heating tube when observing through water and electricity.
The reasons are more complicated. The currently known reasons are: a. When the heating body is in the incoming material inspection and testing withstand voltage or leakage current (common withstand voltage testers have two modes of dynamic test and static test), the error will be dry The burning test time exceeds five seconds, resulting in a certain degree of dry burning of the heating tube and slight changes in the dielectric layer, and hot spots appear in the subsequent use process, which causes the temperature control to jump and is not easy to reproduce; b. The second reason is a low-level error , But it is difficult to be analyzed, that is, the SUS444 stainless steel substrate tube is not clean enough, and there are oil stains or other stains on the inner wall surface. When the heating tube works for the first time or in the early stage, the oil stain causes the water to not contact the inner wall of the stainless steel tube well, and cannot take away the heat in time, resulting in local hot spots, causing the thermostat to jump or the heating element plastic shell to burn yellow or even black.
3. Tube bursting during use may be a problem with the printing quality of thick film circuits, and the tube bursts due to local hot spots during use. In the past few years, it was more common on the thick film heating tube of the palladium-silver paste system. In the past two years, it has been greatly improved with the improvement of printing machine accuracy;
4. The odor of the water is serious. The whole machine has no obvious odor when the cold water is discharged. However, when the water is boiled or when the first cup of water is taken overnight, a clear odor can be felt, most of which are plastic. The possible reasons are as follows: a. The heating tube assembly shell or other structural parts are made of engineering plastics, such as V0 grade PA66+30% GF containing flame retardant. The flame retardant volatilizes peculiar smell after heating. At the same time, the heating tube components and the whole machine have guide rods, sealing rings or water pipes made of silica gel, which have strong adsorption capacity to absorb the odor of flame retardants. b. The second reason is a problem in the industry, that is, the peculiar smell of the small motor of the diaphragm pump. c. The material of the spiral guide rod in the heating tube assembly is NG. For example, non-food grade engineering plastics are used, or plastic particles provided by black-hearted suppliers are adulterated.
