Process ports and fittings
Selecting the best process port or fitting is just as critical as selecting the correct pressure or flow technology for your specific application. Although Alicat’s devices are typically shipped with either M5 or NPT female process ports, Alicat offers many additional customization options, depending on your requirements.
Process ports are physically welded or machined with device flow bodies, whereas fittings are removable and interchangeable. In other words, process ports describe permanent connections on devices and fittings describe temporary ones.
What is the difference between process ports and fittings?
Process ports are physically welded or machined with device flow bodies, whereas fittings are removable and interchangeable. In other words, process ports describe permanent connections on devices and fittings describe temporary ones.
NPT process ports and fittings
FNPT, or Female National Pipe Thread, is the default process port thread connection on Alicat’s devices. A tapered connection, NPT is the standard thread in the United States for most default applications. Alicat devices come with default NPT thread sizes ranging from 1/8” to 2” based on each device’s flow rate specifications. When using PTFE tape to seal NPT fittings on Alicat devices, do not wrap the first two threads in order to avoid any contamination of the main flow body.
In addition to NPT process port threads, Alicat offers a range of NPT fittings which allow for mixed connections such as NPT to compression and SAE to NPT adapters.
Advantages
-
- United States standard thread connection
- Fittings are easily available and affordable
- No need for O-rings
- Variety of end connection adapters available
Disadvantages
-
- Requires PTFE tape
- Small leaks possible based on variance in manufacturing quality, materials, and installation of fittings
- Overtightening can cause thread damage over time
- Parts more expensive outside US
- Not as common in liquid applications
BSPP process ports and fittings
BSPP stands for British Standard Pipe Parallel. These straight process port threads are default connections used in Europe. Sometimes BSPP is also denoted BSP or simply with the letter G (ISO Standard). Alicat offers BSPP connection threads from 1/8” to 2.0.”
Advantages
-
- British standard thread connection
- Parts common in Europe
- Generally better sealing than NPT
- Overtightening causes less thread damage than NPT
Disadvantages
-
- O-Rings must be compatible with gases or liquids used
- Small leaks possible based on variance in manufacturing quality, materials, and installation of fittings
- Parts harder to find outside Europe
SAE process ports and fittings
SAE stands for the Society of Automotive Engineers threads. These are straight process port threads usually used in vacuum applications. SAE is often indicated by fitting size and sometimes by thread size. For identification, Alicat’s part numbers will use the fitting size and its description will use the thread size. Alicat offers J1926 and AS5202 SAE process ports from 1/8” to 1-1/4” and various SAE fittings.
Advantages
-
- Helium leak check compatible threads
- Better sealing than NPT and BSPP threads
- Parts are easily located in US
- Easy to assemble and disassemble connections
- Overtightening causes less thread damage than NPT
Disadvantages
-
- O-Rings must be compatible with gases or liquids used
Swagelok compression process ports and fittings
Alicat offers Swagelok compression process ports and adapter fittings which are also referred to as two-ferrule Swagelok tube fittings. These process ports and fittings create hard seals using a tightened nut and are rated up to 15,000 PSIG. To connect, bottom out tubing inside the fitting body and tighten the nut 1-1/4 turns from finger tight. Alicat offers process ports for compression in 1/4″, 1/2” and 3/4” sizes and Alicat provides Swagelok compression fittings in 1/4″, 3/8”, and 1/2” and 3/4” sizes.
Advantages
-
- Helium leak check compatible fittings
- Easy to assemble connections
- Parts are easily located in US
- High pressure rated (up to 15,000 PSIG)
- Variety of end connection adapters available
Disadvantages
-
- VCR and VCO better for vacuum applications
Swagelok VCR process ports
Alicat also offers Swagelok VCR process ports which are ideal for vacuum and positive pressure applications. These connectors use metal gasket face seals for greater leak-resistance. Welded VCR process ports are rated from 7100 PSIG at 1/8” to 3000 PSIG at 1”. These are generally used in high purity gas lines or where space is limited. To connect, simply align both gland connections, utilize new gaskets and tighten the connecting nuts. Alicat provides Swagelok VCR process ports from 1/8” to 1” sizes.
Advantages
-
- Vacuum rated with extremely low leak rate
- Components can be removed without bending lines
- Fluid compatibility
- Metal-to-metal seal
- Parts are easily located in US
Disadvantages
-
- Need to weld, swage or flare to attach to tubing
- Gaskets can fall off when disassembling
- Lower pressure rated relative to other Swagelok fittings
Swagelok VCO process ports
Alicat also offers Swagelok VCO process ports which create vacuum seals using an O-ring. VCO fittings allow for rapid assembly for use in high-pressure, low-pressure, and high purity gas applications.
Advantages
-
- Components can be removed without bending lines
- Rated to same pressure as compression fittings up to 15,000 PSIG
- Vacuum rated with extremely low leak rate
- Quick assembly
- Wide range of temperature compatibility
- Parts are easily located in US
Disadvantages
-
- Need to weld, swage or flare to attach to tubing
- O-rings can fall off when disassembling
- O-rings must be chemical compatible
Down port process ports
Alicat also offers down port process ports which use underside connections to attach to manifolds or other custom configurations. These down ports allow for devices to mount from the bottom using through-holes, O-rings, bolts, and nuts. Instead of flowing side-to-side, both inflow and outflow are on the bottom. Alicat offers three down main port process port options:
-
-
NeSSI-compliant down port (NESSI)
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Down port, mounting screws thread from below (DPORT)
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Down port, mounting screws thread from above (TMDPORT)
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Advantages
-
- Works well with manifolds
- Unique plumbing configurations
Disadvantages
-
- Not useful in standard plumbing configurations
NPT process ports and fittings
FNPT, or Female National Pipe Thread, is the default process port thread connection on Alicat’s devices. A tapered connection, NPT is the standard thread in the United States for most default applications. Alicat devices come with default NPT thread sizes ranging from 1/8” to 2” based on each device’s flow rate specifications. When using PTFE tape to seal NPT fittings on Alicat devices, do not wrap the first two threads in order to avoid any contamination of the main flow body.
In addition to NPT process port threads, Alicat offers a range of NPT fittings which allow for mixed connections such as NPT to compression and SAE to NPT adapters.
Advantages
-
- United States standard thread connection
- Fittings are easily available and affordable
- No need for O-rings
- Variety of end connection adapters available
Disadvantages
-
- Requires PTFE tape
- Small leaks possible based on variance in manufacturing quality, materials, and installation of fittings
- Overtightening can cause thread damage over time
- Parts more expensive outside US
- Not as common in liquid applications
NPT female threads
| NPT Size | M-Series | Whisper |
| 1/8” | 100 SCCM to 20 SLPM | 50 SCCM to 5 SLPM |
| 1/4″ | 50 to 100 SLPM | 10 to 20 SLPM |
| 1/2″ | 250 SLPM | 40 SLPM |
| 3/4″ | 500 to 2000 SLPM | 50 to 500 SLPM |
| 1” | – | – |
| 1-1/4” | 3000 SLPM | – |
| 1-1/2” | 4000 to 5000 SLPM | – |
| 2” | – | 1000 SLPM |
*Full scale flow rates 50 SCCM and lower for M-Series use M5. Full scale flow rates 20 SCCM and lower for Whisper use M5.
Alicat also offers threaded compression fittings for our default NPT process ports.
BSPP process ports and fittings
BSPP stands for British Standard Pipe Parallel. These straight process port threads are default connections used in Europe. Sometimes BSPP is also denoted BSP or simply with the letter G (ISO Standard). Alicat offers BSPP connection threads from 1/8” to 2.0.”
Advantages
-
- British standard thread connection
- Parts common in Europe
- Generally better sealing than NPT
- Overtightening causes less thread damage than NPT
Disadvantages
-
- O-Rings must be compatible with gases or liquids used
- Small leaks possible based on variance in manufacturing quality, materials, and installation of fittings
- Parts harder to find outside Europe
BSPP "G" threads
| BSPP Size | M-Series |
| 1/8” | 100 SCCM to 20 SLPM |
| 1/4” | 50 to 100 SLPM |
| 3/8” | 50 to 250 SLPM |
| 1/2” | 250 SLPM |
| 3/4” | 500 to 2000 SLPM |
| 1.5” | 4000 to 5000 SLPM |
*Full scale flow rates 50 SCCM and lower for M-Series use M5. Full scale flow rates 20 SCCM and lower for Whisper use M5.
Alicat also offers threaded compression fittings for our default NPT process ports.
SAE process ports and fittings
SAE stands for the Society of Automotive Engineers threads. These are straight process port threads usually used in vacuum applications. SAE is often indicated by fitting size and sometimes by thread size. For identification, Alicat’s part numbers will use the fitting size and its description will use the thread size. Alicat offers J1926 and AS5202 SAE process ports from 1/8” to 1-1/4” and various SAE fittings.
Advantages
-
- Helium leak check compatible threads
- Better sealing than NPT and BSPP threads
- Parts are easily located in US
- Easy to assemble and disassemble connections
- Overtightening causes less thread damage than NPT
Disadvantages
-
- O-Rings must be compatible with gases or liquids used
SAE threads
| Dash Size | O-Ring Thread | M-Series |
| M5 (10-32 UNF) | – | 0.5 to 10 SCCM |
| 2 | 5/16-24 | 10 to 50 SCCM |
| 4 | 7/16-20 | 100 SCCM to 10 SLPM |
| 6 | 9/16-18 | 20 to 100 SLPM |
| 8 | 3/4-16 | 250 SLPM |
| 10 | 7/8-14 | 500 to 1000 SLPM |
| 12 | 1-1/16-12 | 1500 to 2000 SLPM |
| 16 | 1-5/16-12 | 3000 SLPM |
| 24 | 1-7/8-12 | 4000 to 5000 SLPM |
NPT process ports and fittings
FNPT, or Female National Pipe Thread, is the default process port thread connection on Alicat’s devices. A tapered connection, NPT is the standard thread in the United States for most default applications. Alicat devices come with default NPT thread sizes ranging from 1/8” to 2” based on each device’s flow rate specifications. When using PTFE tape to seal NPT fittings on Alicat devices, do not wrap the first two threads in order to avoid any contamination of the main flow body.
In addition to NPT process port threads, Alicat offers a range of NPT fittings which allow for mixed connections such as NPT to compression and SAE to NPT adapters.
Advantages
-
- United States standard thread connection
- Fittings are easily available and affordable
- No need for O-rings
- Variety of end connection adapters available
Disadvantages
-
- Requires PTFE tape
- Small leaks possible based on variance in manufacturing quality, materials, and installation of fittings
- Overtightening can cause thread damage over time
- Parts more expensive outside US
- Not as common in liquid applications
NPT female threads
| NPT Size | M-Series | Whisper |
| 1/8” | 100 SCCM to 20 SLPM | 50 SCCM to 5 SLPM |
| 1/4″ | 50 to 100 SLPM | 10 to 20 SLPM |
| 1/2″ | 250 SLPM | 40 SLPM |
| 3/4″ | 500 to 2000 SLPM | 50 to 500 SLPM |
| 1” | – | – |
| 1-1/4” | 3000 SLPM | – |
| 1-1/2” | 4000 to 5000 SLPM | – |
| 2” | – | 1000 SLPM |
*Full scale flow rates 50 SCCM and lower for M-Series use M5. Full scale flow rates 20 SCCM and lower for Whisper use M5.
Alicat also offers threaded compression fittings for our default NPT process ports.