To help users judge the quality of fused quartz equipment, this article briefly introduces the identification methods for evaluating fused quartz equipment quality.
The quality of glass-lined equipment is determined by both its external and internal quality. External quality can be qualitatively assessed through visual inspection and instrumental testing, whereas internal quality refers to the microscopic, intangible defects inherent within the equipment due to inadequate material selection, shaping, welding, surface treatment, and firing during the manufacturing process, as well as insufficient quality control in each stage. These defects may manifest during transportation, storage, or use, leading to equipment failure. Internal defects cannot be detected by any means and can only be minimized through strict quality management and scientific, reasonable process discipline. In other words, every step in the manufacturing process of glass-lined equipment must be strictly controlled to ensure the quality of each unit. However, under the intense market competition, many companies find it challenging to achieve this. As an industry leader, our company can guarantee the quality of our products. We assure all customers of their safe and reliable use. Currently, poorly made, shoddy, and substandard equipment is widely prevalent in the market.
Below are some insights into identifying the quality of glass-lined equipment.
The external quality of glass-lined equipment can largely reflect the internal quality's superiority or inferiority.
Estimated glass-lined equipment
Wipe the surface dust of the glassware with a dry cloth (not a wet one). Inspect under normal lighting; the glass surface should be bright. If the porcelain surface is as clear as a mirror and can reflect a clear image of a person's face, it is considered high-quality. Additionally, closely examine the surface of the glassware for the absence of the following defects:
Should be dense without any tiny pores.
b. The surface should be free of glaze tumors, blisters, irreversible impurities, and significant color variation; for closed tanks larger than 6300L, the porcelain surface, especially at the manhole, upper and lower flange areas, bottom head ring welds, and bottom liquid outlet, should not have linear streaks (a technical term referred to as "hairline cracks").
c. The ceramic surface shows no significant scratches. In our country's glass-lined equipment, due to the differences in glass firing technology between domestic and foreign processes, only the glass lining surface, which is about 0.2mm thick, is dense. Below this, there are many bubbles, meaning that this 0.2mm thickness serves as an effective corrosion-resistant layer with high strength. Deep scratches can damage this dense layer, reducing the strength of the glass-lined layer. Therefore, it is strictly prohibited to allow hard objects into the glass-lined equipment during inspection, installation, and use to prevent scratching.
d. The glass frit surface at the welding seam should be free of any noticeable protrusions. Here's a professional tip: The glass frit layer on the metal substrate, specifically at the outer arc areas, is subject to tensile stress at higher temperatures due to the difference in thermal expansion coefficients between the glass frit and the metal substrate. The glass frit's tensile strength is significantly lower than its compressive strength, making it prone to cracking under tensile stress. Therefore, it is advisable to minimize the occurrence of protrusions on the metal substrate and to smooth out any protruding weld seams as much as possible.
The glass frit surface should be free of any noticeable dents. Dents are defects left by the grinding of the metallic substrate steel plate surface. The more dents there are, the poorer the surface quality of the steel plate, which is not suitable for glass frit equipment.
f. The steel plates at the pipe end and head, manhole and head, and high-neck flange and cylinder welding joints should have no significant thickness differences.
Defects typically arise in large-scale equipment, as manufacturers fail to process or select suitable pipe ends and high-neck flanges based on the actual thickness of the equipment's steel plates. Instead, they use pipe ends and high-neck flanges suitable for small-scale equipment on large-scale equipment, resulting in thickness discrepancies at the joint areas. The larger the scale, the more pronounced the thickness difference, which can reach 6 to 8mm in severity. Such abrupt changes in the thickness of the metallic substrate are highly detrimental to the quality of the glass lining. Due to the significant thickness variations, the equipment experiences large temperature differences during heating and cooling, leading to substantial thermal stress in the glass lining after cooling. During operation, as the temperature changes, the residual stress is released, causing damage to the glass lining. Additionally, it should be noted that the steep changes in the thickness of the metallic substrate during the firing process can cause inconsistencies in the reaction speed of the glass lining, leading to differences in the microstructure of the glass lining. In areas with lower temperatures, the reaction process is not yet complete, and the ideal microstructure has not been formed when the equipment is removed from the furnace.
This defect is entirely preventable. Its existence highlights the manufacturer's neglect of quality and management shortcomings.
