Process ports and fittings

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.

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View all thread and fitting options

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 whereas 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 NFT 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 standard 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. As process ports, VCR is 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. As fittings, this 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)
  • Down port, mounting screws thread from below (DPORT)
  • Down port, mounting screws thread from above (TMDPORT)

Advantages

  • Works well with manifolds
  • Unique plumbing configurations

Disadvantages

  • Not useful in standard plumbing configurations

Contact an applications engineer for support

 

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”
2” 4000 to 5000 SLPM 1000 SLPM

*Flow rates below 100 SCCM for M-Series use M5. Flow rates below 20 SCCM for Whisper use M5.

Alicat also offers threaded compression fittings for our default NPT process ports.

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

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

Compression fittings (Swagelok compatible)

Compression Size M-Series
1/4″ compression 100 SCCM to 100 SLPM
3/8” compression 50 to 250 SLPM
1/2″ compression 50 to 500 SLPM

VCR fittings

VCR Size and Gender M-Series
1/8” VCR female 0.5 to 50 SCCM
1/4” VCR male 100 SCCM to 100 SLPM
1/2″ VCR male 50 to 250 SLPM
1” VCR male 500 to 3000 SLPM

VCO fittings

VCO Size M-Series
1/8” VCO 0.5 to 50 SCCM
1/4″ VCO 100 SCCM to100 SLPM
1” VCO 500 to 3000 SLPM
  • NeSSI-compliant down port (NESSI)
  • Down port, mounting screws thread from below (DPORT)
  • Down port, mounting screws thread from above (TMDPORT)