Pneumatics connectors -- types of threads and sizes

[gowniak13]

Hello guys, I need advice and helpI am a maintenance technician at food manufacturing place, my boss requested me to fix air leaks around machinery pointed by the external

energy usage survey.The problem is I don't have experience with pneumatics installations, most of the leaks are around connectors, fittings etc

there are places where i can stick a lot of ptfe tape and that does the job, but there are places where fittings are corroded and needs

to be changed and here is where my questions raisehow do i recognize type of threads and sizes usedsome air lines are in mm, some air pipeworks are inches, some are bsp, any guide? advice? do i measure inside or outside, its

very difficult for me as there are like 50 types of connectors, couplers, reducers and quick fittings used here and therewhat about pressure regulators ? some of them have cracked filter bowls, so I can't fix that, I could replace that, but its still the case

of proper size of thread, hose, pipework etcAnd I am going to be responsible for ordering parts :(

 

[berkeman]

Welcome to PF.

Can you post a few pictures of the typical fittings and piping that you are working on? Also, do you have a pair of calipers that you can use to measure the OD of some of the pipes and fittings? Do you have a small ruler with fine inch and mm scales that you can use to measure the # of threads per inch/cm, etc.?

https://upload.wikimedia.org/wikipedia/commons/1/18/Caliper_detail_view.jpeg

 

[gowniak13]

Hello Berkeman, unfortunately I don't have any photos just now

I do have caliper and its metric only same as tape, I think I understand now what I need to properly measure

 

[dlgoff]

Here's a thread and end connection identification guide. see attached .pdf file.

 

[Baluncore]

... how do i recognize type of threads and sizes used some air lines are in mm, some air pipeworks are inches, some are bsp, any guide? advice? do i measure inside or outside, ...

You are on a steep learning curve, and that experience goes on forever.

Compile a kit of reference examples for BSP and NPT.
Expect to find some UN and metric threads.

Because pipe threads are often tapered, measuring the diameter will not always identify the system.
I first measure the exact pitch in TPI = 8, 10, 11, 11½, 14, 18, 19, 26, 27, 28; or in mm.
It could then be;
BSP = 28, 19, 14, 11, 10, 8.
NPT = 27, 18, 14, 11½, 8.
or Brass = 26.

Since only 8 tpi and 14 tpi pipe threads are shared by BSP and NPT. I next measure the profile angle to see if it is the deep 55° British thread, or the shallower 60° which makes it NPT, UN, or ISO metric.

 

[Tom.G]

https://www.google.com/search?&q=thread+gauge+tool
Very handy thing to have around, even for us electronic folks.

 

[dlgoff]

https://www.google.com/search?&q=thread+gauge+tool
Very handy thing to have around, even for us electronic folks.

bold by me.

Especially if you are wanting the separation between the plates of a parallel plate capacitor