Excess Steam Quench / Seal Leaking From Asphalt Pumps

Depends on what type of seals you have....some are made to leak a bit, and the packing needs to changed periodically....Do you have a maintenance history on the pumps?...and are they packed type seals?

https://blog.craneengineering.net/the-basics-of-mechanical-seals

many of them are plan 62

I see that API Plan 62 doesn't really distinguish among various conditions for different pumped fluids, but the purging of oxygen from the seal face could be a primary function of the steam, maybe heat / seal housing is not important.

So then you might be able to reduce steam until you were sure no air is entering the drain connection, maybe you don't need 2 psig of steam pressure.

This source (McNally Institute) is cited in several locations:

http://www.mcnallyinstitute.com/03-html/3-6.html

Quench is used to control temperature behind the seal, if steam with asphalt, would be to keep it warm. So your steam condenses as it gives up heat to the seal cavity, and the water must escape somewhere, preferably not into the asphalt, I suspect.

So if you shoot the seal casing with perhaps an IR thermometer, that will tell you if you have enough steam, the temperature will be close to the 100C steam temperature. If not enough steam, the temperature will be lower.

The pump manufacturer's data, buried in some instruction book for the equipment, will tell you what temperature they recommend for the product you are pumping.

I spoke to our flowserve guy and he basically told me to make sure the steam isn't more than 2-3psi and to eyeball the amount of steam coming from the stuffing box.

What if the steam is running at 1-2 psi but there's still a significant amount of excess steam coming out?

Are you supposed to be heating or cooling, would be one question to answer. If you blow the steam through so fast it doesn't condense, the heat transfer will be poor, which you may want, or might not want.

Also, what is the variability of your steam flow/pressure? You may not always observe high demand periods where the steam pressure might drop for longer times than you might consider acceptable, for temperature or oxidation upsets. Plant historical trend data may show you why the pressures are adjusted the way they are...

This is where it gets tricky. Per Flowserve, you will need to take a calibrated eyeball and adjust the amount of steam to a lower flow rate. I suspect this will be below 1 psi. I suspect a pressure gauge will become less useful and you will need to adjust to a visually acceptable flow of steam, maybe a light puff from the discharge port.

Initially, you will want to check this 2-3 times a day. Eventually, you will get comfortable with the operating condition and will check once a week. Make sure nobody plugs the discharge port. That defeats the purpose of the steam purge!

One more question, are you using a pressure regulator to adjust the steam pressure? In my opinion, that is the most reliable means to adjust this system. A globe valve or ball valve adjustment is not self-regulating and will need constant adjustment.