Inexpensive flush mount DP transducer (WWTP maybe)

I work in a Batching Chemical facility. In most applications I use one of the big instrument vendors, Rosemount, Siemens, E&H, Honeywell etc....

However, I have a new application where I need an inexpensive Differential Pressure transducer/transmitter. It needs to be flush mount, this is a very dirty process and fouling is a major issue. I suspect something designed for the Waste Water treatment industry will be my best bet. Needs to have a 4-20mA output, and a NEMA 4 rating. Expected DP will be in the 0-50 psig range. Accuracy is not critical anything in the 5-10% range will work.

I will be mounting this on a two bag filter inlet & outlet, and when the DP reaches a setpoint, stop a pump and alert the operator, all the logic will be handled by a PLC.

I've done a few searches on the net, but have had zero success with the flush mount requirement.

Has anyone ever used something like this? A web link would be greatly appreciated.


thanks,

Ken

The paper industry uses a G1xx internal threaded adapter, which welds into the process line/vessel. When the transmitter is screwed into the adapter, O-rings seal the process, and the flush diaphragm forms a flush surface on the wetted side.

Go here
http://www.lesman.com/acatalog/WIKAAnalogPressureTransmitters.html
to see both the flush mounts and Wika's conventional 3A triclamp style sanitary transmitters.

Note that these are lower cost xmtrs because they're not 'smart', they're dumb, fixed range transmitters.

A G1xx adapter is sold under the accessories link at the bottom of the page. Its number doesn't look right. Be sure to check to make sure the adapter matches the process fitting.

Dan

Dan

Thanks Danw.
I don't see a DP transmitter, but other than that, they are exactly what I was looking for.
I will need double the wiring, and double the AI channels, and calculate the DP in the PLC.

Again thanks for the link.

Ken

Ken.
I don't know what their presence in the USA is like but I have always found Trafag to be good for applications which do not warrant a full blown process instrument. It might be worth a quick Google.
Andybr

Sorry, Ken, I missed the 'differential' part. You were clear, but I missed it.

I'm not aware of anything beyond remote capillary seals on industrial DP's, like you already mentioned, or doubling up flush mounts like those I linked to.

Dwyer has some really cheap DPs but they're made for clean gas or air and if you need flush mount you're not measuring DP across clean air. So you'd still have the problem of flush mount and sensing tubing from the process to the gauge, and then you're right back into remote seals on Rosemount, Honeywell, E&H, Siemens, etc.

Dan

I'm going with the WIKA units, one of my local reps. carries this, so reduces the paper work.
I'm trying to negotiate better pricing because I need 20 of these things for 10 filter stations.

Again, thanks for the link.