Valves are essential to fluid control and safe production in fine chemicals, agrochemicals, pharmaceutical chemicals and other chemical sectors. Typical conditions include low to medium pressures, vacuum or slight positive pressure, low flow rates, and multi-product, small-batch production. These differ from the high temperatures, high pressures and large flows of petrochemical processing. Corrosive, sterile, highly toxic or coke-forming media require customized valve selection, with an emphasis on small bores, tight shut-off, precise flow control, easy changeover, corrosion resistance, explosion protection and sanitary performance.

The following six sectors cover the complete process from raw material preparation through finished product storage and transport, identifying key applications, suitable valve types and selection priorities.

1. Fine Chemicals

Process characteristics: Multi-product, small-batch and customized production typically operates under vacuum or slight positive pressure, at medium or low temperatures, with corrosive or high-purity media. Precise flow control, tight shut-off, contamination prevention and easy product changeover are essential. Media include high-purity organic solvents, acid and alkali reagents, pharmaceutical and electronic intermediates, dyes, pigments and food additives.

1. Raw material preparation: Use 316L stainless steel diaphragm valves and miniature ball valves for high-purity solvents and additives, fluorine-lined miniature ball valves for corrosive feedstocks, and miniature needle valves or high-precision control valves for gram- or kilogram-scale dosing. Bellows-sealed globe valves help prevent contamination during purification.

2. Core synthesis: Vacuum ball valves or diaphragm valves serve vacuum reactors, with a specified leak rate of ≤10⁻⁶ Pa·m³/s. Fluorine-lined diaphragm valves or Hastelloy ball valves suit highly corrosive reactions. Explosion-proof pneumatic ball valves and emergency shut-off valves serve flammable or explosive processes. Throttling and bellows-sealed globe valves regulate reflux.

3. Separation and purification: High-precision control valves meter feed to vacuum distillation columns; low-flow control valves regulate reflux (reference accuracy: ±0.1). Vacuum bellows-sealed globe valves handle overhead and bottom discharge. Fluorine-lined diaphragm valves serve precision extraction, vacuum diaphragm valves serve vacuum drying, and bellows valves support nitrogen blanketing.

4. Filling, storage and transport: Miniature needle or diaphragm valves provide millilitre-scale bottle filling. Fluorine-lined miniature valves handle corrosive products, while bellows valves and sanitary diaphragm valves serve high-purity or sterile products. Use 316L stainless steel ball valves and miniature breather valves on storage tanks.

5. Utilities and environmental protection: Stainless steel globe valves and steam traps serve steam systems; miniature butterfly or ball valves serve cooling water. Fluorine-lined butterfly valves and explosion-proof control valves support organic solvent exhaust recovery. Fluorine-lined diaphragm valves handle low-concentration wastewater.

Key valve types: Vacuum ball and diaphragm valves, miniature needle valves, high-precision control valves, fluorine-lined diaphragm valves, explosion-proof pneumatic ball valves and bellows-sealed globe valves.

2. Agrochemicals

Process characteristics: Toxic, highly corrosive and coke-forming media are common in batch synthesis at medium temperatures and pressures. Tight shut-off, corrosion resistance, anti-coking performance, explosion protection and easy cleaning help prevent cross-contamination. Typical media include active ingredients and intermediates, pyridine and pyrethroid compounds, strong acids, phosphides, organic solvents, emulsifiable concentrates and suspensions.

1. Raw material preparation: Fluorine-lined diaphragm valves and explosion-proof pneumatic valves contain highly toxic phosphide or pyridine feedstocks. Fluorine-lined ball or gate valves handle acids. Corrosion-resistant, high-precision control valves maintain the required ingredient ratios.

2. Active ingredient synthesis: Fluorine-lined butterfly or ball valves serve reactor connections; carbide-sealed valves resist coking. Explosion-proof pneumatic sequence-control valves support staged feeding. Heat-resistant fluorine-lined globe valves serve hot reflux lines, check valves prevent reverse flow, and emergency shut-off valves isolate toxic media if leakage occurs.

3. Separation and purification: Fluorine-lined control and ball valves resist corrosion during distillation and solvent removal. Wear-resistant fluorine-lined butterfly valves handle solid-liquid separation and filter residue. Fluorine-lined bellows-sealed globe valves help prevent contamination during solvent recovery.

4. Formulation and filling: Use 316L stainless steel ball and control valves to regulate solvent ratios in emulsifiable concentrates, and wear-resistant pneumatic butterfly valves for powder-containing suspensions. Fluorine-lined filling valves with flowmeters provide drum dosing; miniature diaphragm valves provide drip-free bottle filling. Provide leak-containment guards in highly toxic filling areas.

5. Utilities and environmental protection: Stainless steel globe valves and steam traps serve steam systems. Fluorine-lined butterfly valves serve cooling water and toxic exhaust absorption, together with corrosion-resistant control valves for hydrogen sulfide or hydrogen chloride. Fluorine-lined diaphragm or ball valves handle concentrated wastewater; wear-resistant pneumatic butterfly valves handle pesticide filter residue.

Key valve types: Fluorine-lined diaphragm, butterfly and ball valves; explosion-proof pneumatic sequence-control valves; corrosion-resistant precision control valves; carbide-sealed wear-resistant valves; emergency shut-off valves; and fluorine-lined filling valves. Selection priorities: Tight shut-off throughout, packless diaphragm valves for highly toxic media, and straight-through passages where coking is likely.

3. Pharmaceutical Chemicals

Process characteristics: Sterile, vacuum, high-purity and low-temperature processes require hygienic design, no dead spaces, CIP/SIP capability, contamination prevention, precise dosing and sterile sealing. Applicable GMP, USP and FDA requirements must be considered. Typical media include active pharmaceutical ingredients and intermediates, sterile solvents, amino acids, peptides, acid/alkali buffers, injectables and oral formulations.

1. Raw material preparation: Sanitary bellows and diaphragm valves with mirror-polished surfaces (Ra ≤0.8 μm) transfer sterile high-purity solvents. Sterile precision control valves and miniature needle valves provide gram-scale dosing. Sanitary ball valves support inert gas blanketing.

2. API synthesis: Sanitary diaphragm valves serve sterile reactors and support SIP with 121°C steam. Sterile vacuum diaphragm valves serve vacuum reactions, cryogenic sanitary ball valves serve reactions at −20 to −80°C, and dead-space-free sanitary throttling valves serve reflux lines.

3. Separation and purification: Sanitary bellows-sealed globe valves and vacuum diaphragm valves serve vacuum distillation and crystallization. Sanitary diaphragm valves protect sterile filtration, and sanitary vacuum valves serve freeze-drying; bellows valves support nitrogen blanketing.

4. Formulation and filling: Sanitary diaphragm valves maintain dead-space-free injectable preparation. Medical miniature needle or diaphragm valves provide microlitre-scale, drip-free filling of infusion bottles and vials. Food-grade sanitary ball valves serve oral formulations. Sanitary diaphragm valves and sterile breather valves serve formulation tanks.

5. Finished product storage and transport: Sanitary diaphragm valves support sterile API packaging; sanitary bellows valves serve transfer lines; cryogenic sanitary ball valves serve low-temperature biopharmaceutical storage.

6. Utilities and environmental protection: Sanitary globe valves and steam traps serve pure steam. Sanitary diaphragm or ball valves serve purified water and water for injection under applicable GMP requirements. Sanitary butterfly valves handle dilute sterile wastewater; explosion-proof pneumatic valves and fluorine-lined valves handle organic solvent exhaust.

Key valve types: Sanitary diaphragm and ball valves, sterile vacuum diaphragm valves, medical miniature needle valves, sanitary bellows valves, cryogenic sanitary valves and high-precision sterile control valves. Selection priorities: Mirror-polished 316L stainless steel, no dead spaces or packing seals, suitability for 121°C steam sterilization, and applicable GMP/USP/FDA requirements.

4. Biochemicals

Process characteristics: Fermentation and enzymatic processing generally operate at ambient temperature and pressure, under sterile, microaerobic or anaerobic conditions. Media contain microorganisms, biomass or fermentation broth. Sterility, no dead spaces, resistance to biological deposits, easy cleaning and low shear protect cell integrity and enzyme activity. Media include glucose and starch feeds, enzymes, bioethanol, organic acids and biodegradable polymer feedstocks.

1. Raw material preparation: Low-shear sanitary butterfly or ball valves transfer starch and glucose feeds and help prevent gelatinization. Sanitary diaphragm valves serve sterile or purified water. Sanitary control valves regulate sugar concentration and pH during proportioning.

2. Fermentation: SIP-capable sanitary diaphragm valves provide sterile sealing at fermenter inlets and outlets. Sanitary vacuum diaphragm valves exclude air in anaerobic fermentation; miniature sanitary control valves regulate oxygen addition in microaerobic operation. Programmable sanitary diaphragm valves provide timed feeding, and sanitary check valves prevent backflow contamination.

3. Separation and purification: Sanitary butterfly or diaphragm valves serve centrifugation and filtration. Sanitary bellows valves serve organic acid and alcohol refining. Sanitary vacuum diaphragm valves support crystallization and drying with nitrogen blanketing.

4. Product refining and filling: Sanitary diaphragm or ball valves handle enzymes and organic acids. Explosion-proof sanitary ball valves serve bioethanol filling. Wear-resistant sanitary butterfly valves handle biodegradable polymer feedstocks containing small amounts of powder.

5. Utilities and environmental protection: Sanitary globe valves and steam traps serve steam; sanitary butterfly valves serve cooling water. Fluorine-lined diaphragm valves resist organic acid corrosion in high-COD fermentation wastewater, and wear-resistant sanitary butterfly valves handle biomass solids.

Key valve types: Sanitary diaphragm, butterfly and ball valves; sanitary sequence-control valves; miniature oxygen control valves; sterile vacuum diaphragm valves; and sanitary check valves. Selection priorities: Packless, dead-space-free diaphragm designs, low shear, CIP/SIP capability and mirror-polished 316L stainless steel.

5. Chemical Fibres

Process characteristics: Continuous fibre production combines high temperatures, molten polymers and high viscosity, with corrosive spinning auxiliaries. Valves require heat resistance, resistance to sticking, tight sealing, long service life and high flow capacity to reduce downtime. Typical media include polyester melts, nylon and acrylic polymers, ethylene glycol, purified terephthalic acid (PTA), spinning oils and acidic or alkaline spinning additives.

1. Raw material polymerization: Large-bore stainless steel ball or gate valves transfer PTA and ethylene glycol. Heat-resistant ball or globe valves, using chromium-molybdenum steel where appropriate, serve polymerization reactors at melt temperatures above 280°C. Heat-resistant control valves regulate melt reflux and viscosity; high-temperature vacuum ball valves support devolatilization and limit oxidation.

2. Melt transfer and spinning: Large-bore fully welded ball valves provide tight sealing on polyester melt mains to prevent leakage and coking. Three-way or multiport sequence-control ball valves distribute melt to multiple spinning positions. Miniature high-temperature needle valves regulate spinneret feed to maintain fibre diameter. Fluorine-lined diaphragm or ball valves resist spinning oil corrosion.

3. Fibre finishing: Stainless steel butterfly or ball valves serve washing. High-temperature control valves regulate steam during heat setting. Pneumatic ball or butterfly valves support automated fibre cutting and packaging lines.

4. Finished product storage and transport: Wear-resistant pneumatic butterfly valves handle finished fibre silos and resist abrasion from short fibres. Fluorine-lined ball valves and breather valves serve spinning oil storage tanks.

5. Utilities and environmental protection: Heat-resistant gate or globe valves and steam traps serve high-temperature, high-pressure steam. Large-bore butterfly valves serve circulating cooling water. Fluorine-lined butterfly or diaphragm valves handle wastewater containing ethylene glycol or organic acids. Wear-resistant ball or butterfly valves handle coked melt solids.

Key valve types: High-temperature fully welded ball valves, melt-service control valves, miniature high-temperature needle valves, large-bore butterfly and gate valves, fluorine-lined diaphragm valves and steam traps. Selection priorities: Heat-resistant, polished melt-contact surfaces that limit sticking, and fully welded ball valves for long-life, low-maintenance continuous production.

6. Household and Personal Care Chemicals

Process characteristics: Pastes, emulsions, surfactants, fragrances and food-grade ingredients are processed at ambient temperature and pressure, often at low flow rates. Suitable food or personal care grades, odour-free materials, resistance to sticking, easy cleaning and accurate dosing maintain consistent product quality. Typical media include shampoo and shower gel, detergent surfactants, fragrances, colourants, glycerol, alcohols, soap bases and cosmetic lotions or creams.

1. Raw material preparation: Use 304/316L stainless steel ball or butterfly valves for surfactants and glycerol. Miniature needle or diaphragm valves accurately dose fragrances and colourants. Food-grade sanitary diaphragm valves serve food-grade ingredients under applicable FDA requirements.

2. Formulation: Sanitary butterfly or diaphragm valves serve mixing vessels; plunger-type control valves help prevent paste adhesion. High-precision miniature control valves regulate surfactant ratios. Explosion-proof miniature valves handle volatile or flammable fragrances.

3. Emulsification and homogenization: Sanitary diaphragm valves serve emulsifying vessels. Sanitary ball valves and check valves protect homogenizer connections against backflow. Wear-resistant sanitary butterfly valves transfer pastes and help limit deposits on internal parts.

4. Filling and packaging: Sanitary plunger control valves and miniature diaphragm valves provide metered, drip-free paste and emulsion filling. Miniature needle valves serve small bottles; sanitary ball valves and flowmeters serve drums. Use 316L stainless steel ball valves on product tanks, and miniature breather valves on fragrance tanks to limit evaporation.

5. Utilities and environmental protection: Stainless steel globe valves and steam traps serve steam. Miniature butterfly or ball valves serve cooling water. Stainless steel butterfly or diaphragm valves handle surfactant-containing wastewater. Explosion-proof pneumatic ball valves support fragrance exhaust recovery.

Key valve types: Food-grade or sanitary diaphragm and butterfly valves, miniature needle valves, high-precision and plunger-type control valves, and 304/316L stainless steel ball valves. Selection priorities: Appropriate food-contact/FDA requirements, odour-free materials, no dead spaces, and plunger or diaphragm designs for adhesive pastes and emulsions.