Jacoby Tarbox — Sight Flow Indicators
NPT 150# Nominal Rated
Threaded · 1/8" – 2" FNPT · 150 PSI Nominal · Flapper, Plain, Drip, Rotary & ST Stainless Series
NPT 150# Nominal Rated — Threaded Bulls-Eye
Standard threaded sight flow indicators for general service. Four indicator styles: flapper (100-S), plain (100-S NF), drip (200-S), rotary (300-S). Sizes 1/8"–2" FNPT. Engineered per ASME B31.1 & B31.3 with ASTM listed metals only.
The NPT 150# Nominal Rated series is Jacoby Tarbox's standard threaded sight flow indicator line for general service applications. Engineered per the design criteria of ASME B31.1 & B31.3 Power & Chemical Piping Codes, incorporating only ASTM listed metals. Available in four indicator types — flapper (100-S), plain (100-S NF), drip (200-S), and rotary (300-S) — to suit any flow direction and process fluid. Sizes from 1/8" to 2" FNPT with a wide choice of body materials and seal options. Full bore visibility maximizes pipeline view, in most cases with a diameter equal to the nominal pipe size. The ST Series (100-ST, 100-ST NF, 200-ST, 300-ST, and 100-ST-GI glass-to-iron) shares the same 150# nominal pressure rating and is available in the same range of body materials.
Available Models — ST Series
The ST Series carries the same 150# nominal pressure rating and is available in the same range of body materials as the standard series. It adds the 100-ST-GI glass-to-iron seal variant for applications where eliminating an elastomeric window gasket is required. All models are 1/4"–2" FNPT, hydrotested prior to shipment.
Plain sight flow indicator with no internal indicator. Bi-directional and suitable for any orientation. Used where spot indication of media presence, color, clarity, or turbidity is required without a moving indicator.
Body Materials
Cast Iron, Bronze, Carbon Steel, 316 SS, and others
Indicator
None — plain glass view
Flow Direction
Any direction (bi-directional)
Flapper-type sight flow indicator. The 316 SS hinged, wheel-weighted flapper rises with flow velocity, providing a clear visual indication of flow presence and relative rate. Uni-directional — install for horizontal or upward vertical flow.
Body Materials
Cast Iron, Bronze, Carbon Steel, 316 SS, and others
Indicator
316 SS hinged wheel-weighted flapper
Flow Direction
Horizontal or vertically upward (uni-directional)
Drip-type sight flow indicator. The 316 SS drip tube forces low or intermittent flows to collect on the lower lip and drip visibly downward, making even minimal flow rates easy to detect. Uni-directional — horizontal or downward vertical.
Body Materials
Cast Iron, Bronze, Carbon Steel, 316 SS, and others
Indicator
316 SS drip tube
Flow Direction
Horizontal or vertically downward (uni-directional)
Rotary-type sight flow indicator. The TFE rotor spins in proportion to flow velocity, providing a clear indication even in opaque liquids or heavy gases. Bi-directional and multi-orientational. Extra-durable stainless steel rotors available as an option.
Body Materials
Cast Iron, Bronze, Carbon Steel, 316 SS, and others
Indicator
TFE rotor (SS rotor optional)
Flow Direction
Any direction (bi-directional, multi-orientational)
Flapper-type sight flow indicator with a glass-to-iron (GI) seal design. The glass-to-iron construction eliminates the conventional elastomeric window gasket, providing a hermetic seal suitable for higher-temperature service and applications where gasket compatibility is a concern.
Body Materials
Cast Iron, Bronze, Carbon Steel, 316 SS, and others
Indicator
316 SS hinged wheel-weighted flapper
Flow Direction
Horizontal or vertically upward (uni-directional)
ST Series Specifications
| Parameter | Value |
|---|---|
| Connection | FNPT threaded per ASME B1.20.1 |
| Size Range | 1/4" – 2" FNPT |
| Pressure Rating | 150 PSI Nominal |
| Temperature | Up to 300°F standard (100-ST-GI rated higher — consult factory) |
| Body Materials | Cast Iron, Bronze, Carbon Steel, 316 SS, 304 SS, Alloy 20, Hastelloy, Monel, PVC |
| Viewing Glass | Borosilicate glass standard |
| Window Gasket | Neoprene standard; Buna-N, Viton, PTFE available (N/A on 100-ST-GI) |
| Indicator Materials | 316 SS flapper / drip tube; TFE rotor (SS rotor optional on 300-ST) |
| Fasteners | ASTM A354 and ASTM A194 |
| Wetted Components | Meet NACE MR-01-75 / ISO 15156-1 requirements |
| ID Faceplate | Stainless steel engraved |
| Testing | Hydrotested at 1-1/2 times rated pressure prior to shipment |
| Standards | Designed per ASME B31.1 & B31.3; ASTM listed metals only |
How to Order — ST Series Model Code
Specify model base, pipe size, and gasket material. Example: 100-ST-1/2-V = Model 100-ST (flapper), 1/2" FNPT, Viton gasket.
| Pos. | Field | Options |
|---|---|---|
| 1 | Model Base | 100-ST (NF) · 100-ST · 200-ST · 300-ST · 100-ST-GI |
| 2 | Size (FNPT) | 1/4 · 3/8 · 1/2 · 3/4 · 1 · 1-1/4 · 1-1/2 · 2 |
| 3 | Window Gasket | N = Neoprene (std) · B = Buna-N · V = Viton · T = PTFE · (blank = GI seal on 100-ST-GI) |
| 4 | Rotor Material (300-ST only) | Standard = TFE · SS = Stainless Steel rotor |
Contact Northeast Controls for special materials, sizes outside standard range, or high-temperature applications.
General Series Specifications
| Parameter | Value |
|---|---|
| Connection | FNPT threaded per ASME B1.20.1 |
| Size Range | 1/8" – 2" FNPT (3" available with Style 960-F) |
| Pressure Rating | 150 PSI Nominal |
| Temperature | Up to 300°F standard |
| Body Materials | Cast Iron, Bronze, Carbon Steel, 316 SS, 304 SS, Alloy 20, Hastelloy, Monel, PVC |
| Viewing Glass | Borosilicate glass standard |
| Seal Materials | Neoprene standard; Buna-N, Viton, PTFE, Silicone available |
| Indicator Types | Flapper (100-S), Plain (100-S NF), Drip (200-S), Rotary (300-S) |
| Fasteners | ASTM A354 and ASTM A194 (Class 150 models) |
| Wetted Components | Meet NACE MR-01-75 / ISO 15156-1 requirements |
| ID Faceplate | Stainless steel engraved |
| Testing | All units hydrotested at 1-1/2 times rated pressure |
| Facility | Machined and assembled in ISO-9001 fully automated facility |
Typical Applications
Jacoby Tarbox NPT 150# sight flow indicator sales
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