Design Features Of Pneumatic Sanitary Stainless Steel Tl Type Welded Directional Valve

In multi-product processing lines, different media—water, oil, CIP chemicals—share the same piping. A mixproof valve with double-seat design prevents cross-contamination, even if one seal fails. The TL-type welded valve features two independent plug seals, with a leakage chamber between them open to atmosphere. If a seal fails, leaking media drains through a dedicated outlet, never mixing with the other fluid. Available in 304 or 316L stainless steel, sizes 1.5″–4″, with PTFE/EPDM/NBR seals. Pneumatic actuation, pressure up to 10 bar, temperature -10°C to 120°C.

The Cross-Contamination Threat

Single-seat valves allow mixing if a seal fails. This compromises product integrity, triggers recalls, and wastes batches. A mixproof valve eliminates this risk through two independent seals. Each seal provides independent shut-off, making it impossible for fluids to mix even if one seal leaks.

Double-Seat Design and Leakage Control

The valve operates with two independently controlled stems. When closed, two seals separate upper and lower pipelines. The leakage chamber between them opens to atmosphere via a detection port. If a seal fails, leaking media flows into this chamber and exits through the leakage outlet, providing positive leak detection and preventing cross-contamination. When the valve opens, the leakage chamber closes, allowing flow from one line to another.

Key design features:

1. Two independent plug seals for dual separation

2. Integrated leakage chamber with detection port

3. Pneumatic actuator for remote automated control

4. Welded connections for permanent, crevice-free joints

5. 304 or 316L stainless steel with Ra ≤ 0.8 µm finish

Material and Seal Options

The valve body is available in SS304 or SS316L. SS304 suits water, oil, and general service. SS316L provides molybdenum-enhanced corrosion resistance for aggressive or high-purity applications. Seal materials include PTFE (chemical resistance), EPDM (water and general service), and NBR (oil resistance). Welded connections eliminate gaskets and threaded joints. Internal surfaces polished to Ra ≤ 0.8 µm prevent bacterial adhesion and support CIP/SIP.

Specifications and Selection Criteria

Applications and Selection Considerations

The valve mixproof configuration is used in dairy processing, beverage production (flavor changeovers), CIP systems, and oil/water separation.

When selecting:

• Media compatibility determines seal material — PTFE for chemicals, EPDM for water, NBR for oil.

• Pressure rating must match system pressure — standard up to 10 bar.

• Size depends on line diameter — 1.5″-4″ covers most applications.

• Actuation — pneumatic for automated processes; manual available.

Mixproof valves meet 3-A, EHEDG, and FDA standards for hygienic design.

Installation and Maintenance

Weld valve per qualified procedures. Connect leakage outlet to a drain for visual leak detection. Connect pneumatic supply (4-7 bar) and control signal. Valve supports CIP without disassembly. Inspect seals and leakage chamber regularly. Replace seals every 12-18 months.

This valve design eliminates cross-contamination risk in processing facilities where product integrity is critical. The TL welded mixproof valve provides secure, automated separation of incompatible media.

Pneumatic Sanitary Stainless Steel  TL Type Welding Reversing Valve 

• We can supply Sanitary Manual Reversing Valve, Hygienic Pneumatic Divert Valve, Sanitary T Type Divert Valve, Hygienic L Type Divert Valve, Sanitary LL Type Reversing Valve.
• The series of valve are major let the medium reach the purpose of reversing or end stop, because the good sealablity and cleanability, they are extensively use to different sanitary industry areas.
• The series of pneumatic cut-off reversing valve change the energy which process by compressed air to the mechanical energy, the mechanical energy can drive the valve rod axial moving, thus move the different location of seal elements, which can control the switch for inlet of pipeline, finally realise the purpose of medium reversing or stop.
• The manual cut-off reversing valve series control by handle, also reach the purpose of medium reversing or stop at the end.

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