Repair & Refurbishment of Diaphragm Seals

Diaphragm Seals are used to separate the pressure instrument from the process to protect the vulnerable measuring element. This protection enhances the lifetime of the measuring instrument significantly. However, it is possible that the diaphragm eventually breaks. One of the advantages of Diaphragm Seals is that they can be renewed, whilst re-using the pressure instrument. It will function just as a new instrument, but with the benefits of lower costs and a much shorter lead time, compared to buying a new instrument with seals. In addition to short lead times, we also offer rush repairs (within 48 hours) and when requested we analyze the defective instrument to learn what has happened and advice how to improve the reliability and lifetime of the instrument in the future.

Examples of damaged diaphragm seals

Diaphragm is bulged

It happens frequently that the diaphragm is bulged. A possible cause could be that the process temperature has been too high and the filling fluid has cooked, resulting in a bulged diaphragm. Check the temperature specifications on the datasheet with the process. Another possible cause is the presence of hydrogen diffusion. This means that very small hydrogen ions (H+) have permeated the diaphragm and joined together again behind the diaphragm, resulting in a bulged diaphragm. Of course, the measurement is no longer correct. The solution preventing hydrogen permeation is a gold plated diaphragm. Badotherm offers a unique 40 µm layer, ensuring a longer lifetime.

Diaphragm is bulged

It happens frequently that the diaphragm is bulged. A possible cause could be that the process temperature has been too high and the filling fluid has cooked, resulting in a bulged diaphragm. Check the temperature specifications on the datasheet with the process. Another possible cause is the presence of hydrogen diffusion. This means that very small hydrogen ions (H+) have permeated the diaphragm and joined together again behind the diaphragm, resulting in a bulged diaphragm. Of course, the measurement is no longer correct. The solution preventing hydrogen permeation is a gold plated diaphragm. Badotherm offers a unique 40 µm layer, ensuring a longer lifetime.

Diaphragm is blown up

Sometimes a diaphragm is “blown up”. This can be caused by a high pressure water jet stream directed at the diaphragm, but it can also be a sign that the application has
leaked and/or is on a vacuum. Extra care should be taken into account for installation, mounting and/or maintenance to prevent this problem from recurring.

Diaphragm is blown up

Sometimes a diaphragm is “blown up”. This can be caused by a high pressure water jet stream directed at the diaphragm, but it can also be a sign that the application has
leaked and/or is on a vacuum. Extra care should be taken into account for installation, mounting and/or maintenance to prevent this problem from recurring.

Diaphragm is corroded

Some processes are so aggressive that they corrode the diaphragm material. A correct selection of diaphragm material ensures a longer lifetime. Badotherm can assist and advise in making the selection. Several types of diaphragm materials are available from Badotherm (a.o.Tantalum, Monel 400, Titanium Gr. 1, Duplex 2205, Hastelloy C-276, Nickel 201 or Inconel 600). Also, exotic flange materials are readily available.

Diaphragm is corroded

Some processes are so aggressive that they corrode the diaphragm material. A correct selection of diaphragm material ensures a longer lifetime. Badotherm can assist and advise in making the selection. Several types of diaphragm materials are available from Badotherm (a.o.Tantalum, Monel 400, Titanium Gr. 1, Duplex 2205, Hastelloy C-276, Nickel 201 or Inconel 600). Also, exotic flange materials are readily available.

Diaphragm is dented

The diaphragm has a thickness of only 75 micron and thus transmits the pressure accurately. However, it is also very sensitive and vulnerable and needs to be handled with care. In case the diaphragm is dented, it no longer gives a correct reading. A renewal of the Diaphragm Seal is the solution. In the example of an extended type the diaphragm can be removed, the flange cleaned and machined, and a new diaphragm is welded to it, then, the complete application is mounted and filled and tested. The instrument is as good as new.

Diaphragm is dented

The diaphragm has a thickness of only 75 micron and thus transmits the pressure accurately. However, it is also very sensitive and vulnerable and needs to be handled with care. In case the diaphragm is dented, it no longer gives a correct reading. A renewal of the Diaphragm Seal is the solution. In the example of an extended type the diaphragm can be removed, the flange cleaned and machined, and a new diaphragm is welded to it, then, the complete application is mounted and filled and tested. The instrument is as good as new.

Process medium behind diaphragm

When the diaphragm is damaged and the process medium gets behind the diaphragm a hazardous situation can exist. Because the complete system stays more or
less liquid filled and continues to transmit a (process) pressure. This could give the (wrong) impression that the application is still functioning correctly. In the meantime, the
process medium could corrode the flange material, which could lead to a dangerous situation. A periodic check to see if the diaphragm is still in perfect condition is recommenced, especially with corrosive processes.

Process medium behind diaphragm

When the diaphragm is damaged and the process medium gets behind the diaphragm a hazardous situation can exist. Because the complete system stays more or
less liquid filled and continues to transmit a (process) pressure. This could give the (wrong) impression that the application is still functioning correctly. In the meantime, the
process medium could corrode the flange material, which could lead to a dangerous situation. A periodic check to see if the diaphragm is still in perfect condition is recommenced, especially with corrosive processes.