Full Internal Rubber Lined Dual Plate Check Valve

Description

TECHNICAL DATA SHEET

Product: Full Internal Rubber Lined Dual Plate Check Valve
Type: Wafer, Dual Plate, Spring-Loaded, Full Bore
Document No.: TDS-CHK-DP-FULL-LINED-EPDM-CF8M
Date: 24-June-2026

1. VALVE DESCRIPTION

This is a wafer-type, dual plate check valve designed with full internal rubber lining for maximum corrosion resistance. The entire internal flow path—including the valve body bore, disc faces, hinge pins, and spring cavities—is completely encapsulated with EPDM rubber. The base material of the body and discs is CF8M (Cast 316 Stainless Steel), combining structural strength with the chemical resistance of EPDM. This design ensures that no metallic components are exposed to the process fluid, making it ideal for aggressive chemical media such as acids, alkalis, seawater, and chlorinated solutions.

The dual plate configuration, assisted by independent springs, provides non-slam closure, low cracking pressure, and can be installed in horizontal or vertical (upward flow) pipework.

2. DESIGN STANDARDS

Valve Design: API 594 (Wafer Type, Dual Plate Check Valve)
Face-to-Face Dimension: API 594 (Short Pattern)
Flange Compatibility: Flangeless wafer body installs between ASME B16.5 (Class 150/300), EN 1092-1 PN 10/16 flanges
Pressure / Temperature Rating: ASME B16.34 (Applicable to stainless steel base material, derated per EPDM lining limits)
Testing & Inspection: API 598
Rubber Lining Standard: Compliant with ISO 289-1 / ASTM D412 for EPDM properties; visual inspection 100%, spark tested at 10 kV (pinhole-free guarantee)
3. TECHNICAL SPECIFICATIONS

Parameter Details
Available Size Range 2″ – 48″ (DN50 – DN1200)
Pressure Class ASME Class 150 / PN 10, PN 16 (standard); Class 300 on request
Body Type Wafer, Dual Plate
Body Base Material CF8M (ASTM A351 Gr. CF8M) — Cast equivalent of AISI 316 Stainless Steel
Internal Lining Material EPDM Rubber (Ethylene Propylene Diene Monomer)
Lining Coverage Full internal coverage: body bore, disc surfaces, hinge pin, spring housings, and seal faces
Lining Thickness 3 mm – 5 mm (uniform, non-porous, vulcanized / bonded)
Disc Base Material CF8M (ASTM A351 Gr. CF8M), fully encapsulated in EPDM
Spring Material Hastelloy C276 or 316 Stainless Steel, optionally EPDM coated
Seat / Sealing Integral EPDM seat molded on disc and body; bubble-tight shutoff
Cracking Pressure ≤ 0.05 bar (0.7 psi)
Operating Temperature Range -20 °C to +120 °C (-4 °F to +248 °F), EPDM dependent
Leakage Class Zero Leakage (API 598, Resilient Seated)
Installation Orientation Horizontal or Vertical (upward flow only)
Flow Direction Arrow Permanently marked on body
4. MATERIALS OF CONSTRUCTION

Component Material Specification
Body CF8M Stainless Steel ASTM A351 Gr. CF8M (316 SS)
Body Internal Lining EPDM Rubber Full coverage, integral to body bore
Disc (2 pcs) CF8M Stainless Steel ASTM A351 Gr. CF8M, fully encapsulated in EPDM
Hinge Pin CF8M or 316 SS Encapsulated within EPDM lining
Spring Hastelloy C276 / Inconel / 316 SS Isolated from flow by EPDM encapsulation
Stopper Pin CF8M Retained inside lining
Bushing PTFE / PEEK (if any) For low friction, located behind lining
External Body Coating Pickled and passivated (natural) Optional: Epoxy coating on external surface
5. KEY DESIGN FEATURES

Full Internal Lining Technology

The CF8M valve body is completely lined internally with EPDM via a high-pressure molding and vulcanization process.
All wetted surfaces are EPDM, including the entire disc set, hinge area, and spring compartments. The springs and hinge pins are completely sealed inside the rubber encapsulation, eliminating any exposure to aggressive fluids.
Corrosion & Chemical Resistance

CF8M base material provides excellent structural integrity even if external corrosion is a concern, and adds secondary corrosion protection should the lining be damaged (safe-layer design).
EPDM lining offers outstanding resistance to dilute acids, alkalis, oxidizing agents, seawater, and many chlorinated solutions. Not suitable for oils, hydrocarbons, or concentrated oxidizing acids.
Non-Slam, Low Pressure Drop

Each disc has an independent, torsion spring. The design allows the valve to close quickly before flow reversal, preventing water hammer.
Streamlined disc profiles ensure low pressure loss and high Cv values.
Seat Design

The seat is integrated into both the disc and body lining, creating an EPDM-to-EPDM sealing interface. No separate seat ring is required.
Bubble-tight shutoff at low and high pressures, with self-cleaning action due to disc movement.
6. TESTING & INSPECTION

Hydrostatic Tests per API 598:

Shell Test: 1.5 × CWP at ambient temperature.
Seat Test: 1.1 × CWP, zero leakage acceptable.
Lining Integrity:

100% spark test (holiday detection) at 10,000 V DC.
Hardness test (Shore A) per ASTM D2240.
Adhesion test per ASTM D429.
Documentation: EN 10204-3.1 material certificates for body/disc and lining properties, NDT reports, and final inspection certificate supplied as standard.
7. LIMITATIONS

EPDM is not resistant to mineral oils, greases, fuels, and strong concentrated oxidizing acids (e.g., concentrated nitric acid). Please consult factory for chemical compatibility charts.
The valve is designed for clean to slightly loaded liquids. Slurries with sharp abrasive particles may reduce lining life.
8. APPLICATIONS

Ideal for corrosive fluid check service in:

Chemical processing plants (acids, alkalis, salt solutions)
Chlor-alkali industry (brine, caustic soda, hypochlorite)
Seawater cooling loops and desalination
Wastewater treatment with chemical additives
Mining and mineral extraction (acidic leach solutions)
Pulp and paper (bleaching chemicals)
Note: Valve dimensions, pressure/temperature derating curves, and certified assembly drawings are provided upon order placement. The manufacturer reserves the right to modify materials and design for continuous product improvement.