Diaphragm Seal of a Pressure Transmiter

Use an isolator between the gauge and the process fluid.

Thanks for the answer lyn.

We have this type of transmitter

http://www.google.cl/imgres?um=1&hl=es-419&sa=N&tbo=d&biw=1140&bih=520&tbm=isch&tbnid=MqMed80CkgFy1M:&imgrefurl=http://www.tradekorea.com/products/271505/Pressure_Transmitters.html%3BJSESSIONID_TK%3D4h6GK8bWdpHnnf4T7Kfxrjjn1G9dy2fMLXRThs9t29FH95dCZJhG!-146681928!731366051%3FoutMax%3D30%26nationCd%3D%26certNm%3D%26linkFlag%3D&docid=1ntPEEuF3RwO8M&imgurl=http://web.tradekorea.com/upload_file2/product/586/P00229586/cbe9caa5_27bcb2b4_e1cc_4fdf_b8fe_2b72ca0686ef.jpg&w=1500&h=635&ei=ptCvUIWAFYfK9gSh54D4Bw&zoom=1&iact=rc&dur=470&sig=113669158949297111534&page=1&tbnh=120&tbnw=266&start=0&ndsp=18&ved=1t:429,r:6,s:0,i:102&tx=172&ty=63

that is already isolated from the process fluid for a diaphragm seal, like is showed in the scheme.

http://en.wikipedia.org/wiki/File:Seal_(diaphragm).png

So we installed a flush ring between the gauge flange and the process flange to clean that diaphragm seal.

When you refer to an isolation, was it that type of isolation what you mean? or other type of isolating?

Thanks in advanced.

Is this a new installation?

Did it ever work acceptably, OK?

Was it orginally installed without flush rings? And the problem was ? ?

Immediately after flushing, how accurate is the level reading?

How big is the error after flushing? (example: drifts 40mm w.c. in 2 minutes after flushing)

What are you comparing the transmitter level reading to as a level reference? WHat level reading do you trust?

Are the level readings stable when the level is stable?

What are the LRV and URV values?

What is the tank height between the seal flanges?

What are the dimensions of the tank.

Where are the sensors located on the tank?

How critical is the level?

How critical is the Brix of the mixture?

What is the operating temperature?

What is the operating pressure(s)?(MINIMUM/MAXIMUM?)

What is the process liquid?

I can offer valid suggestions when I have the requested information.

What are the dimensions of the tank.

it's an evaporator

Where are the sensors located on the tank?

at the suction of the recirculation pump and in the space above the level of liquid that accumulates the juice at the bottom

How critical is the level?

it's controlled around 40%

How critical is the Brix of the mixture?

Very Critical

What is the operating temperature?

Around 70-80°C

What is the operating pressure(s)?(MINIMUM/MAXIMUM?)

400-500 mbar, it depends on the product

What is the process liquid?

a sugar solution (long chains) of around 50 % Brix

What you have is build up of sugar on the external ridges of the seal, the only way you can eliminate this is to use a smooth faced seal, or install not a flushing ring but a flush with steam directly onto the face of the seal with a timer so it periodically cleans the seal face.

Thanks for the answer

Could I use a flush ring like the one on the next image for steam in place or this is not going to be applicated directly onto the face of the flush ring?

http://www.omicron.org.in/flushing-ring.html

Thanks in advanced.

Dawn, The Answer to your questions:

Is this a new installation?

The flush ring was a new modification to wash the seal ring that exists at the beginning of the operations of the evaporator.

Did it ever work acceptably, OK?

Yes, about a month after the flush ring was installed.

Was it orginally installed without flush rings? And the problem was ?

It was originally without flush rings, and the level readings were inaccurate, because the sugar in the solution solidifies.

Immediately after flushing, how accurate is the level reading?

It was accurate.

How big is the error after flushing? (example: drifts 40mm w.c. in 2 minutes after flushing)

I can't answer, but when the sensor is clean, it works well.

What are you comparing the transmitter level reading to as a level reference? WHat level reading do you trust?

We are comparing the level with the visual reading at the peephole.

Are the level readings stable when the level is stable?

Yes

What are the LRV and URV values?

What is the tank height between the seal flanges?

About 20 ft

Your link shows a flushing ring (the Omicron). That's what I consider a flushing ring. So it isn't clear what it is that you have installed now that you call a flushing ring, if you plan on replacing it with the Omicron.

What do you have installed now, that you call a flushing ring?

Yes, We had installed a flush ring like the Omicron, but with 4 holes. My question was if this flush ring could be adapted to work with cleaning with steam

Is the transmitter mounted at the bottom with the diaphragm facing up? Can the transmitter be mounted so the the diaphragm is vertical or facing down? It seems that solids settling out is your problem, and if you can mount the transmitter with the diaphragm in a different orientation it may solve your problem.

Thanks

The diaphragm is mounted vertically