Installing Pressure Transmitter

Hi,

I am looking for some help on installing pressure transmitter on a pipe. Do you have to drill hole in the pipe and then mount the transmitters directly?

Any help or web links will be appreciated.

Thanks,

Mr. Pressure Transmitter

It depends on the application. There are flange mounted pressure transmitters and the type that you screw into a nipple. The distributer that you are purchasing it from should be able to help you out there?

The one that I am looking is having a 1/2" NPT connection

You should be able to find it in Grainger catalog.
Is it similar to This?

There are 2 ways to do this. A joint could be broken apart and a tee or Y installed.

IF the pipe is "tight" the tees added length may not make it easy to rejoin the connections. In that case you will need to cut the pipe and rethread it then add the tee.

Many people put a Tee in the line. Most are reluctant to drill and tap the pipe directly, especially in higher pressure applications, because the thickness of the pipe wall isn't really made for holding an NPT threaded connection - not enough threads in the thickness of a pipe wall.

I've welded couplings or half-couplings to larger pipe to provide an NPT connection.

Dan

danw said:

the thickness of the pipe wall isn't really made for holding an NPT threaded connection - not enough threads in the thickness of a pipe wall.

I've welded couplings or half-couplings to larger pipe to provide an NPT connection.

Dan

Click to expand...

Agreed.

I recommend an anvilet when the pipe is not threaded and can not have a fitting inserted for the transmitter to thread into. http://www.canvil.com/pages/catalogs/fsa-p6.htm

danw said:

I've welded couplings or half-couplings to larger pipe to provide an NPT connection.

Dan

Click to expand...

Ever done it on a "live" 3" gas line??..I still cringe when i am in the same room and they are arc welding and drilling a coupling on the gas line...It just gives me the willies!!

Well, google, it depends.

I do a lot of work on low pressure (less than 15 psig)large diameter air lines, and it is common to simply drill and tap the pipe if it is schedule 40 or similar.

For small diameter pipes the tee approach is best.

For thin wall pipe at low pressure you need to drill the pipe and weld a coupling to it to mount the pressure.

For high pressure pipe you want to use a weld-o-let for the tap.

For high pressure rated pressure vessels you need a "nozzle" in the vessel wall.

For intermediate pressure pipe applications you can use a saddle tee from Grainger, McMaster Carr, etc.

You can mount the transmitter remotely and use a tubing connection for gas, but with a liquid you need to affset for the height difference between the tap and the transmitter.

You should also think about installing a valve before the transmitter so you can remove it when you want to exchange it, otherwise you have to let the pressure out of the system when you do it.

It's good engineering practice to always use a block and bleed valve between the process and the transmitter. On very high pressure systems a double block and bleed is recommended.
The block and bleed allows the pressure source to be isolated, and then the insturment bleed down in a controlled manner. Depending on specific application, this can also allow calibration in place, and also limits exposure to potentionally hazardous materials.

There are many block and bleed mfgs. here's a link to one:
BLOCK&BLEED