DURALINE™ Recirculating Laboratory Faucets — Natural Polypropylene (PPN) or PVDF
How it works (core): For return-to-tank DI/UPW loops using a non-pressurized reservoir. A factory-installed compact recirculating module sits below the deck at the inlet of the thru-deck nipple shank. Module ports are 3/8" FNPT inlet from the supply loop and 3/8" FNPT outlet back to the tank. A 0.125" ID recirculating tube seats inside the module, exits the outlet, and returns water to the reservoir to keep the loop moving when the dispense valve is closed.

Materials & purity (wetted path): Natural PP or PVDF; Virgin PTFE seals; no elastomers or lubricants used in construction; non-metallic path; zero-dead-leg at dispense.

Ports & tube interface: Module 3/8" FNPT inlet and 3/8" FNPT outlet; accepts 0.125" ID recirculating tube that returns to the non-pressurized tank.

Key specs: Target velocity ≥ 4.5 ft/s (with 0.125" ID tube, about 0.2 GPM ≈ 5.2 ft/s); pressure rating 120 PSI.

Valve & control: DURALINE control valve with positive shutoff and 120° metering; encapsulated PTFE shutoff seal kept in compression for constant on/off duty; PTFE stem seal; renewable cartridge enables in-place service.

Models: DL-DDR-2 (Natural PP) · DL-DDR-3 (Natural PVDF).

Applications:
  • DI/UPW benches requiring continuous return-to-tank circulation between dispenses
  • High-purity labs mitigating stagnation and biofilm risk at the point of use
  • Multi-faucet series loops with a common return to a non-pressurized reservoir

Series piping note: For faucets in series, use a common return and introduce a small downstream ΔP (diverter tee, valve, or orifice plate) at each faucet to ensure positive recirculation while maintaining dispense pressure.

Installation notes: Use like materials across components; follow best-practice joining for PP or PVDF; verify velocity at the recirculating tube and set the required ΔP when piping in series.

Next step: Select an Item # below for full specifications, installation details, and downloads.