Gents,
I'm quite new to pressure vessel codes, I usually deal with a specialized pump part. Vessels are used as part of a support system to keep the part I'm familiar with cool and clean while in service. I hear my customers talk about requirements for a U stamped vessel when the internal...
One way to reduce the problem during start-up is to use a liner of sorts that acts like a lip seal on the shaft sleeve. Imagine a PTFE gland gasket that extends into the seal chamber that then tapers down and "rides" on the shaft sleeve just a bit further into the seal chamber than the seal...
The other possibility is that the gland was distorted during installation. If the bolts fastening the gland to the pump were overtightened it is possible to distort the gland plate. This is fairly easy to look into- check to see if the high spots line up with the gland bolt holes. If so, this...
Each number is a different seal support plan.
Plan 72 is the introduction of a buffer gas between the process and containment mechanical seals. This is used to "sweep" leakage to the containment vessel or to a flare/ collection header system. Pressure specified here is for the Nitrogen or...
One advantage of this arangment is that with the bellows facing inwards the seal faces are within the barrier fluid flow allowing more heat transfer to the fluid. Rotating the bellows forces the seal faces towards each end of the glands and out of the flow. In my experience this allows the...
Just noticed something that might be confusing:
In a Plan 52 the restriction I mentioned is between the reservoir and vent or flare header not in the circuit between the reservoir and seal.
More often that not, major seal vendors can also supply these seal support systems and are happy to...
There are 2 basic systems that use reservoirs.
API Plan 52: Unpressurized dual mechanical seals use a reservoir and piping to provide a circuit for fluid between two seals. The reservoir is often connected to a vent or flare header in such a way that leakage from the 1st seal can collect in...
I am pretty certain that DuPont will take a sample and perform some destructive testing to ascertain the composition. Greentweed or Parker would likely also do the same for you.
The answer is that it depends.
The availability of a flare or nitrogen header might help dictate which is used. The lubricity of the process fluid, concentration of solids, how toxic the process fluid is, or how high the seal chamber pressure is might push a user to a pressurized or...
I assume you're going with a pusher design with pefluoroelastomer o-rings- at least with the outboard seal.
There are some other options available for hot services that require dual seals. Dual gas/steam seals have been put to market recently for high temperature services by at least two of...
Just curious- what kind of pump are you using in this service?
At first glance a dual seal does seem to be a good option. A high viscosity service like this one makes start-up extraordinarily difficult for a seal lubricated by the process fluid. Not that start-up isn't going to be difficult...
With some basic pump and process/fluid information your salesperson should also be able to come up with numbers regarding heat soak and heat generated by the seal faces to help you make informed decisions on seal support systems.
