How to select valves for media that are fluorine-containing, chlorine-containing, have solid particles, and are viscous?
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Medium: calcium fluoride (80%), calcium hydroxide, calcium carbonate; contains chloride ions and organic matter; fluoride content: 1000 ppm; moisture content of the residue: 2%; in the form of particles (30%), powder (10%), and lumps (60%). The solid material becomes harder under compression, and it has a certain degree of stickiness. Temperature 70°C, pressure before valve –50 kPa, double-acting, air-operated! Flange pressure: 16 kg; valve body material: 304; ceramic lining; leakage rating: VI; opening frequency: 10 times per minute; negative pressure required. 2. The torque of the actuator shall be no less than 25,000 N/m. 1. The valve body is equipped with drainage holes to facilitate cleaning when the material inside the valve gets clogged. 2. Are there any requirements regarding the tools to be used during cleaning, in order to avoid damaging the valve internals? 3. Ceramics do not conduct electricity; how can static electricity be induced? The medium contains fluorine, so I’ve ruled out ceramic valves. Fluorinated-lined valves are not wear-resistant and cannot be used; what other options are there? We welcome everyone to contribute their ideas and discuss together the best approach.
For the medium you described, which contains fluorine and chlorine and features viscous as well as hard solids, conventional ceramic-lined valves and fluorine-lined valves may indeed not be able to meet the requirements for wear resistance and corrosion protection. The following types of valves can be considered: 1. Metal material valves: Choose valves made from corrosion-resistant metal materials with high hardness, such as Hastelloy or titanium alloy valves. These materials are not only corrosion-resistant but also possess good mechanical strength and wear resistance. 2. Ductile iron valves: Ductile iron possesses good wear resistance and high compressive strength. Ductile iron materials can be considered, and a special coating (such as epoxy resin or a special plastic coating) can be applied to the inner surface of the valve to improve its corrosion resistance. 3. Hard-sealed ball valve: Uses cemented carbide materials (such as tungsten steel) as the sealing surface, offering improved wear and corrosion resistance. Hard-sealed ball valves are suitable for media containing solid particles and can achieve good sealing performance. Regarding static electricity issues, if the main material of the valve is metal, static electricity can be dissipated through grounding to ensure the safe operation of the system. Furthermore, due to the viscosity of the medium and the risk of blockages, it is advisable to incorporate into valve design features that facilitate cleaning and maintenance, such as removable valve seats or a structure designed for easy cleaning. In summary, selecting the appropriate valve requires taking into account the chemical properties of the medium, the operating environment, and the physical durability of the valve. It is recommended to consult with professional valve manufacturers or suppliers in detail before making a decision, in order to obtain the solution that best meets your application requirements. .