Mechanical seal vs. packing in oil pumps 1

[jeromero]

I do not know if there is a code or regulation to select between packing system and mechanical seals in oil pumps. I think the selection has to depend on pressure, viscosity and temperature. Or is it obligatory to use mechanical seals in oil applications? I have consulted API 610, 685, 682 and ASME B73.3M but I have not found a concrete advice.

Is there any table that relates product, pressure, viscosity and temperature with use of packing and mechanical seals?


Thanks in advance,

 

[1969grad]

Mechanical seals are better for oil service because of lower if any leakage. Packing will require a certain amount of leakage for lubrication.

Leakage is a potential fire problem and is to be avoided as much as possible.

 

[poppeye]

Mechanical seals are definately preferred to packing in many services. Solids and temperature need to be checked carefully. Solids will accumulate at the Mechanical Seal bellows area if not flushed properly thus causing early failure. Temperature is also a problem. Recently a customer using Thermanol at 275F was having problems with coking at the seal bellows area. Found out that the Thermanol heating element was alowing the temp to rise above the 350F coking point in the heater with pieces of coke entering the seal chamber causing failures. We converted them over to a no leak packing from Slade industries. Quite expensive but it worked like a dream. The customer couldn't have been happier. Slade will perform on site installation of their packing systems. As a Flowserve Seal Distributor geting away from our primary product line was a tough decision, but the customers needs dictated which way we went.

Popeye

 

[longeron]

Poppeye,

Doesn't Flowserve have a line of graphite packing? I've heard the Slade presentation before and I'm skeptical about the stuff.

 

[poppeye]

Flowserve does have a graphite packing although the factory stuff is a graphite braid and some with a flax base. I do not use the OEM stuff. Just too cheap for me to put my name on in the repairs I supervise. Fortunately we are not bound by our distributor agreement with the packing. I do know the Slade packing works. I too was very skeptical with their presentation. I took them into my customer and let them put on their dog and pony for them and then let the customer make the decision. The customer was totally and completely fed up with mechanical seals and chose to go with the Slade alternative. I am now a believer in their product. It works! Believe it or not the hotter the oil the better. Within 45 minutes of start up, the stuffing box was running 50deg f cooler than the casing with zero leak off.

Poppeye

 

[rlewis]

Sealing systems are driven by environmental regulations rather than industry standards. I don't know where you are located but we would never use packing in an oil pump. In fact, packing is rarely ever used even in water service since most water is "treated" in one way or another.

 

[ciddik]

Mechanical Seal is the best choice rather than packing, which directly enhance the efficiency of pumps, we used mechanical seal in high temp oil pump & is running successfully from many years.

The proper selection is neccessary

siddik

 

[mogle]

poppeye, you are correct. slade does make a packing that we beleive, after many trial and errors, that is the best on the market today. Most all applications today can be sealed without any leakage by using slade and removing seals from equipment.

mogle

 

[pacwizard]

In response to Popeye, Flowserve does have an improvement to Slade style FGC.
In my experience the highest cost is not always the best and I am certain the FS FGC is lower in price and an improvement over Slade.
Pacwizard

 

[nascent]

I want to change tar pumps from packing to mechanical seals but it is possible for a temperature up to 430F the kind of pumps is the LQ4223 from Viking; in my company says that mechanical seals gave a lot of troubles.The packing seals give leakages and I would like to have zero leak. How could I start the proper selection?

Thanks in advance,