Use of Dresser Couplings
Use of Dresser Couplings
(OP)
I work in a refinery ~ 50 years old and the original owner used many Dresser couplings mostly near the piping connection to an atm storage tank however we have also seen them used on underground piping near valve pits. My guess (or hope) is that they were popular to use for misalignment not that they were looked at as a inexpensive alternative to minor expansion joints. Does anyone have a historical perspective on why they were so popular?





RE: Use of Dresser Couplings
Some of these same features that make the couplings desirable might arguably also be detriments in some applications, particularly when the joining concepts and limitations are not well understood. For example, such stuffing-box couplings in and of themselves, unlike a weld, are not restrained joints, and if the pipes are subjected to forces attempting to overdeflect or pull the joints apart, there is nothing in the coupling itself that will prevent this (supplementary restraint can however be provided with rods/harnesses etc.)
Likewise, the couplings normally employ some sort of rubber or elastomeric seal with perhaps far different properties (including heat, hydrocarbon from inside or ouside the joint, or other resistances etc.?) than the normal steel of some process piping etc. Again, if not well understood, and particularly when not judiciously chosen and assembled properly for the exposures, this can eventually result in problems.
Finally, although not requiring a skilled welder the bolting of the couplings is however some labor-intensive and reliant, and may in larger sizes require proper lubrication and several even, circumnavigations of tightening around the joints to appropriate torque levels. If this sometimes hard work, particularly in larger pipe sizes that have a great many bolts, is not completed with adequate knowledge and diligence, problems(leaks) can also result. Of course, however, there can be various problems with fused or welded joints as well!
Maybe this brief discussion will at least provoke more detailed and/or learned responses.
RE: Use of Dresser Couplings
there is a job near here where it appears the line is leaking and some form of non-threaded or non glued joint was used.
comments?
RE: Use of Dresser Couplings
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Use of Dresser Couplings
I've seen gas pipes open up, but partly due to cold weather shrinkage and partly due to some digging damage to an existing gas line. But these were steel. I understand plastic has a much higher temp coef. of linear change. I'd guess the grip of the coupling is pretty slight also.
Comments?
RE: Use of Dresser Couplings
Then again, I guess there is also the chance of a piece of pipe being inadvertently hooked by a backhoe, or snagged by a moving trenchbox, in process of installation!
RE: Use of Dresser Couplings
They are also used to get small bends in underground piping without actually having to calculate and order an elbow. Dressers can give you up to 3-5 degrees of flex (can't remember exactly, check their website) which over long distances can be a lot of movement.
The most common used coupling is the Style 38, but check their catalog and if you can check the existing coupling for the style.
Remember these are not "expansion" joints. They will give you no linear expansion, but you may be able to get about 2" of total compression. This compression will limit your angular deflection though. Most of these couplings are held into place by a backing ring and a gasket. You can get ones that require a welded clip ring like those commonly found on DI pipe.
There is the chance that the pipe will pull out. It really doesn't take much, you are just overcoming the friction of the backing ring and the gasket. A backhoe or a good 6" ground compaction can pull the pipe.
If you need an actual linear expansion joint, Dresser makes one, I think its the Style 68.
RE: Use of Dresser Couplings