Series DW - Added protection for pipeline systems in high traffic or confined areas.

Dual-window sight flow indicators provide two glass discs on each side, so that if either glass should fail for any reason, the other window can withstand pressures temporarily until the unit can be repaired or replaced. Dual-window sight flow indicators and Factory Mutual System approved dual-window sight flow indicators are available in 150 pressure class NPT models and 150 and 300 pressure class flanged models.

​Models:

150 pressure class NPT dual-window

• DWF: Dual-window NPT SFI (plain)

• DWFF: Dual-window NPT SFI (flapper)

• DWFR: Dual-window NPT SFI (rotator)

• DWFD: Dual-window NPT SFI (drip tube)

​Models:

150 pressure class flanged dual-window

• DWF-F: Dual-window flanged SFI (plain)

• DWFF-F: Dual-window flanged SFI (flapper)

• DWFR-F: Dual-window flanged SFI (rotator)

• DWFD-F: Dual-window flanged SFI (drip tube)

*Product images are for reference only, please refer to general or approval drawings for accurate dimensions.*

Materials of construction for body:

• Standard:

  • ASTM A216 steel gr. WCB*

  • ASTM A351 316L/316 STS gr. CF3M*/CF8M

• Optional:

  • ​ASTM A494 Monel® gr. M-30C

  • ASTM A494 Hastelloy® C CW12MW*

  • ASTM A473 Alloy 20 CN7M

Gaskets:

• Grafoil®

• Garlock IFG-5500

• Consult factory for other materials.

The double, tempered glass window design provides added protection in applications where there is:

• External mechanical impact – if the outer glass is cracked or shattered, the inner glass can temporarily continue in service until the unit can be repaired or replaced.

• Abnormal compressive forces – in maintenance or replacement situations, the housing assists in alignment of the glass and can absorb uneven or excessive compression.

• Thermal shock – in high temperature applications, the inner and outer glass protect one another from an extreme thermal gradient. The air pocket between the glass provides an insulative effect.

• Corrosion – if the inner glass is weakened and it breaks, the outer glass can temporarily contain the fluid, withstand the pressure and continue in service until the unit can be repaired or replaced.