Why are people becoming increasingly fond of ceramic valves?

Metal valves have been widely used across many industries for centuries. However, due to material limitations, their structures and materials have been improved to meet increasingly demanding operating conditions. On the other hand, the use of ceramic materials in industrial valves represents a bold and useful innovation.

Ceramic materials exhibit minimal deformation and possess higher bonding strength than metallic materials. Typically, crystalline materials—such as ceramics—have small atomic radii and high ionic valences. All these properties determine the tensile strength, elastic modulus and hardness of ceramic materials. Due to their brittleness and difficulty in machining, ceramics themselves cannot be widely used. Over the past decade, however, thanks to developments and advancements in martensitic toughening technology, composite materials technology and the concept of nanoceramics, their brittleness, toughness and strength have been greatly improved, leading to their widespread application.

Ceramic valves offer significant socio-economic benefits. Why is this?

1. The use of ceramic valves improves the sealing performance of industrial piping systems whilst minimising leaks, thereby playing a proactive role in environmental protection.

2. The raw materials for ceramic production are widely available and inexpensive; high-performance ceramic materials can be produced using common elements such as aluminium, carbon and silicon, thereby conserving large quantities of metallic materials and rare mineral resources.

3. The use of advanced, innovative ceramic structural materials to manufacture valve sealing components and wear-prone parts has improved the wear resistance, corrosion resistance and sealing performance of valve products, significantly extending the service life of the valves.

4. The use of ceramic valves can significantly reduce the frequency of valve maintenance and replacement, enhancing the safety and stability of the associated equipment operating systems, reducing the workload on workers and saving on equipment maintenance costs.

The ceramic pneumatic three-way diverter valves manufactured by Zhejiang Zhanye Valve Co., Ltd. have seen widespread application in recent years across the petroleum, chemical and mechanical industries. These valves not only significantly improve the flow and sealing performance of industrial piping systems but also enhance the safety and stability of equipment operating systems, whilst playing a positive role in energy conservation and environmental protection. Ceramic materials exhibit minimal deformation, high tensile and compressive strength, and high hardness.

Within the overall structure of the ceramic pneumatic three-way diverter valve, the castings are of critical importance, as they determine the safety of the entire operation. It is worth noting that, with prolonged use, certain issues inevitably arise; therefore, we need to implement improvements to meet practical operational requirements.

Zhan Ye’s technical staff have made the following improvements to the ceramic pneumatic three-way diverter valve:

1. The melting equipment has limited ability to control the composition of the molten iron, and the sand mixing equipment lacks stability. The composition of the molten iron is constrained by various factors such as coke quality, furnace type, air volume and raw material conditions; resin sand is affected by factors such as temperature, resin content and acid dosage. For instance, if the sand is frequently not passed through the regeneration and cooling beds, its temperature remains excessively high, severely compromising the strength of the sand mould. This leads to significant sand expansion in the castings, increasing the likelihood of shrinkage cavities and porosity defects.

2. Loose sand within the mould cavity and the impact of molten iron during pouring directly cause sand holes and sand inclusions. Slag is invariably generated in the molten iron within the melting equipment; during pouring, both solid and liquid slag enter the mould cavity with the molten iron, forming slag holes.

3. During production, the nitrogen content in the molten iron increases with rising temperature and decreases as the carbon equivalent rises. When nitrogen and hydrogen are present together, they readily form gas pores, which are the primary source of porosity.

4. The base plate of the mould has poor rigidity; if it is not placed level before moulding, it may deform, resulting in an uneven parting line on the sand mould. When the upper and lower mould halves are closed, a large gap at the parting line causes dimensional and shape defects at this location.