Mechanical Seal Hydro test vs Pneumatic Test Vs complete pump Hydro Test

[bmw318be]

Hi,

Would Seal hydro test guaranteed and recommended before
The seal is installed in the pump ?

Would the pneumatic Air leak test on the gland is sufficient to guarantee the seal is free from any leak.

Would hydro test pump at 1.5 design pressurre of the casing is rrcommended. Some advise we should hydro test the cimplete pump eith seal at iperating pressure or at 1.5 of operating but not at 1.5 maximum allowable pump pressure.

 

[QualityTime]

We all want to help on this forum! It appears that english is not your first language. But could you try to rewrite your post? It is confusing

 

[bmw318be]

My apologize, I did not check the sentences was many typo errors.


Let me rewrite .

I am concerned with a mechanical seal hydrostatic test, seal is going to be installed in internal gear pump ( Plan 11 and 62) having glands, quench and flush without instrument.

1. Is it recommended to do Seal hydrostatic test before installing in the pump ?

2 Is it true that seal hydrostatic test could only be done with the seal installed in the pump ?

3 Would the pneumatic Air leak test on the gland is sufficient to guarantee the seal is free from any leak ?

4 Would hydrostatic test complete pump at 1.5 times pump maximum allowable pressure is recommended ?.Some seal vendor mentioned that we should hydrostatic test the complete pump with seal installed at operating pressure or at 1.5 of operating but not at 1.5 maximum allowable pump pressure.

 

[EnergyMix]

There is also the translation forum (forum1529) which lets you write a question in your native language. People will help you translate it into technical English and suggest the correct forum for you to post it in (well, you know that it's this one.) You might want to check it out.

Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529.

 

[bmw318be]

It is not well understood ?

 

[flexibox]

If its a cartridge seal it can be bench tested if you had the jigs. You can use air or a suitable medium for a hydro test. If the seal is installed in the pump you can do same air or liquid test. If you use air remember this is more stringent test than liquid medium because of the viscosity.

Make sure the seal can handle 1.5 times max pressure first.

Sounds like seal is fitted in pump and you want to test the seal. Yes you can using both mediums.

 

[bk19702]

The air test for the seal is what API 682 will reference - that test is meant as an integrity check of the cartridge assembly, making sure no o-rings were cut during assembly, faces cracked, etc. It is not meant to provide an indication of the performance of the seal in service under the application process conditions. As stated, if you plan on conducting a hydrotest of the pump with the seal installed, you really need to make sure that the seal can handle the anticipated test pressure: 1.5 times operating pressure should be sufficient for a test pressure of the pump casing with the seal installed; 1.5 times max allowable work pressure of the pump casing is anticipating double and triple jeopoardy, and it may be a little overboard.

Keep in mind that any API cartridge seal should already be pressure tested by the vendor. If you want to perform a second integrity check once the seal is installed in the pump, you can use either medium but you shouldn't need a significant amount of pressure to determine if there are any concerns with the seal intergrity.

 

[bmw318be]

Thx bk, you got my point ! .

I am concerned with unwillingness
Of seal vendor to do hydro test on the seal, due to reasone that they need a pump to do hydro test it. How could seal vendor could hydro test the seal
Without pump ?

Howevet air leak test is done on the gland of the seal by seal vendor

How could the integrity be verified in the case when we going to exaggerate the hydro test on the pump with seal installed to value of maximum allowable pressure 1.5 times.

 

[bk19702]

The integrity could be verified if you detect any leaks during the initial pressurization. You can verify the seal integrity once the seal is installed in the pump by pressurizing the pump casing with air, isolating, and monitoring for loss of pressure (mounting a pressure gauge on the casing or gland). This basically reproduces the pneumatic test that the seal cartridge would be subjected to after assembly by the vendor. A lot of end users do a test similar to this post pump assembly with the seal installed; they don't necessarily pressurize to 1.5 times operating pressure and certainly don't go to 1.5 times MAWP. The seal vendor doesn't need to perform a hydrotest on the seal at assembly; the air test per API 682 is all that is required to determine cartridge integrity. If you specify that the seal will be hydrotested once installed with the pump, then that is a different story and the seal will need to be designed to handle the hydrotest pressure amount. However, if all you are concerned with is verifying integrity once the seal is installed in the pump, pressurize the seal chamber with air, isolate, and check for loss pressure. You should be able to determine quickly if any secondary seals were cut or faces damaged during the cartridge assembly into the pump. The API air test is 35 PSI, with a 2 PSI allowable drop in 5 minutes as the acceptable leakage rate.

 

[bmw318be]

Really appreciates the insights of your imformations,

You mentioned " Keep in mind that any API cartridge seal should already be pressure tested by the vendor" .

Do you mean air leak test or hydrostatic test, is pneumatic test is another term of air leak test too ? .

 

[bk19702]

Air leak test is what I was referring to - that is what is referenced in API 682.