Overview

This document provides comprehensive technical specifications and application details for Richter PFA/PTFE shut-off and control butterfly valves, including wafer-style (NKS, NKS-C) and lug-style (NKL, NKL-C) bodies. These valves are designed for corrosive, hazardous, and pure media across sizes from 50 to 1000 mm (2 to 40 inches).

1. Fields of Application

• Control and shut-off of corrosive and hazardous media such as wet chlorine gas, NaOH, H2SO4, HCl, NaOCl, and chemical effluents.
• FDA-compliant wetted materials suitable for food processing and pharmaceutical industries.
• Handling of free-flowing, low-abrasive bulk materials with metallic disc/stem units.
• Compact design facilitates installation in confined spaces.
• Economical and easy installation and maintenance.

2. Operating Range

• Temperature range: -40 °C to +200 °C (-40 °F to +400 °F).
• Pressure range: Vacuum from 0.1 mbar to 10 bar (0.0015 psi to 145 psi vacuum).

3. Product Features

• Soft-sealing, gas-tight valves with lined or metallic disc/stem units.
• Leak-tight per DIN EN 12266 leakage rate A (zero bubbles), compliant with German Clean Air Act (TA-Luft); NKS and NKL series additionally certified to ISO 15848.
• Optional safety stuffing box for environmentally hazardous media.
• Almost equal-percentage flow characteristics.
• Face-to-face dimensions per ISO 5752 series 20, API 609 Table 1, MSS SP-67 Table 3.
• Flange compatibility with ISO 7005-2 PN10, ASME B16.5 Class 150, and JIS R 2210-10K.
• Anti-adhesive wetted surfaces due to PFA/PTFE lining.
• Valve identification per DIN EN 19 and ASME B16.34.
• Actuation options: lockable hand lever, worm gear with handwheel, pneumatic or electric actuators.

4. Valve Construction and Materials

4.1 Disc/Stem Unit

• Single-piece disc/stem lined with pure PFA for corrosion resistance and low friction; optional antistatic PFA-L version.
• Core materials: Duplex stainless steel 1.4517/CD-4MCu (DN 450-1000 uses SS 1.4435/316L).
• Metallic alternatives: precision cast stainless steel (Duplex 1.4470 for DN 50-200, 1.4404 for DN 250-1000) with polished sealing surfaces.
• Special materials on request: Hastelloy® C22, titanium grade 2.

4.2 Valve Body Lining

• Thick-walled PTFE lining (3-3.5 mm), vacuum-proof.
• Options: modified PTFE for permeating fluids, antistatic PTFE-L, PE-UHMW.
• Wide sealing surfaces ensure reliable sealing even with mating flanges with large radii.

4.3 Sealing

• Elastic silicone insert under PTFE lining for permanent sealing in valve opening.
• Optional FKM (Viton®) insert for chlorine gas applications.
• Double-action, maintenance-free, self-adjusting top and bottom stem sealing with primary seal between body lining and disc/stem shoulder and secondary FKM or FFKM O-ring.
• Leak-tight against atmosphere per German Clean Air Act without safety stuffing box.

4.4 Valve Body

• Pressure-bearing body made of ductile cast iron EN-JS 1049 (0.7043)/ASTM A395.
• Optional stainless steel or carbon/glass-fiber reinforced vinyl ester bodies.
• Long valve neck for optimal heat insulation; stem extensions available.

4.5 Corrosion Protection and Centering

• External epoxy coating for corrosion protection.
• Stainless steel nuts and bolts (except special chlorine electrolysis options).
• Centering per ISO 5211 standard.

5. Special Options for Chlorine Electrolysis

• Viton® elastic insert instead of silicone.
• Permeation-proof modified PTFE body lining.
• Steel nuts and bolts replacing stainless steel.
• Tantalum-coated ductile iron body.

6. Components and Materials Summary

• Body materials: ductile cast iron, stainless steel, reinforced vinyl ester.
• Disc/stem units: Duplex stainless steel, Hastelloy® C22, titanium, PFA-lined.
• Seals and packing: FKM, FFKM, PTFE, silicone.
• Actuators: manual lever, worm gear, pneumatic/electric actuators.
• Safety stuffing box with optional monitoring for hazardous media.

7. Connection Dimensions and Standards

• Flange connections per ISO 7005-2 PN10 and ASME B16.5 Class 150.
• Face-to-face dimensions per ISO 5752 series 20, API 609 Table 1, MSS SP-67 Table 3.
• Valve weights and flange hole patterns detailed for DN 50 to DN 750.
• ISO 5211 actuator mounting dimensions provided.

8. Actuation and Accessories

• Manual lockable hand lever for DN 50-200 (except DN 65 and 125).
• Worm gear with handwheel option.
• Pneumatic and electric quarter-turn actuators compatible (e.g., Richter RA, Norbro, El-o-matic, AMG, AirTorque).
• Optional inductive or mechanical limit switches for position monitoring.
• Stem extensions and special designs available on request.

9. Performance and Compliance

• Leakage rate A per DIN EN 12266 ensures gas-tight sealing with zero bubbles.
• Compliance with German Clean Air Act (TA-Luft) for atmospheric emissions.
• Materials and design suitable for FDA compliance in food and pharmaceutical applications.

Additional Technical Details

• Pressure and temperature suitability varies by body lining and disc material, with specific versions (NKS-C, NKL-C) designed for low temperature and regulatory compliance.
• Torque requirements provided per valve size and disc material, ranging from ~100 Nm (DN 50) to 8000 Nm (DN 750+).
• Flow characteristics tabulated for valve openings from 20° to 90°, including conversion factors to Cv for US customary units.
• Valve weights vary significantly with size and material, from 3 kg (DN 50) to over 480 kg (DN 1000).

Summary

Richter PFA/PTFE butterfly valves offer robust, corrosion-resistant, and versatile solutions for controlling aggressive and pure media in chemical, pharmaceutical, and food industries. Their modular design, broad material options, and compliance with international standards ensure reliable shut-off and control under challenging conditions. Optional features such as safety stuffing boxes, special linings, and diverse actuation methods enhance operational safety and adaptability.