All you need to know about Dresser Style 90 Compression Coupling
Video Transcript (see video below)
Hello. We are talking about Dresser style 90 fitting, it’s also called style 90 compression coupling or compression fitting. This is a style 90 universal coupling, this is a style 90 regular coupling, this is a style 90 compression elbow, and this is a style 90 male adapter. I just want to give you a quick comparison. This is a style 65 coupling that you can see in our other videos, and if you compare it with a style 90, they are both for a 1 inch pipe, and you can see that a style 90 is much heavier than the style 65. They are both are compression coupling, compression fitting, style 65 is 150 pound coupling whereas style 90 is a 300 pound. For a much more rugged application, you will use a style 90.
Style 90 couplings are also very popular in gas applications, and that’s where you use style 90 universal coupling. The main difference between a style 90 universal coupling and a regular coupling is that a universal coupling has a lock ring so it prevents from the pipe pulling out. You can see right here, again, this one is even beefier than this, a slightly different nut to accommodate the lock ring, and I’ll show you that.
Let’s talk about the style 90 universal coupling first that has the ability to restrain the axial movement of the pipe. You can see, this is the lock ring that goes like this. Once you tighten it up, the sealing closes and there are jaws right here that would grip on the pipe and prevent it from pulling out. The other end is pretty much similar, it has a gasket. In fact, this gasket is interchangeable with the style 38 coupling gasket, so it’s a much bigger gasket. In fact, I’ll show you for comparison purpose. If you take the style 65 out, you can see the difference. They both are for 1 inch pipe, but this is, for style 90, a much beefier gasket and a retainer cup, style 65, for much lighter application.
These are the components of a style 90 universal coupling, retainer cup, gasket, lock ring, and the same thing on the other side, like this. The way you put this together is, remember, you just measure the coupling, make a line right here. You don’t want your coupling to be touching in the middle; it’s always good to leave about an inch of room. Subtract an inch from here, make a line here, so start from the very outer, this is the nut, slide this on, this is the lock ring that goes like this, and the way to remember is that the tapered edge goes like this, then the retainer cup. In fact, it’s better to assemble the retainer cup and the gasket. On the gasket and retainer cup, the wedge end is always pointing inside. Put it like this, and like this, slide it on, and once you... Of course, you will use a pipe vise or something to grab onto it, and once you make it tight, the lock ring will grab onto the pipe and prevent any axial pullout. Then you repeat the same thing on the other side and you have a compression coupling.
These can also be used on HDPE pipe, we get that question a lot. You have to remember, if you are using it on a PVC pipe or a PE pipe, then the rigidity of the pipe is also important because this thing will really clamp onto it. We usually recommend that, if you’re using it on a PVC pipe or a PE pipe, then use stiffeners that will prevent the pipe from crushing. But it can be used as long as the size matches, you can use it on a PVC pipe also.
This is a style 90 regular coupling. This does not have a lock ring; that’s the only difference between this one and the universal coupling. You can see. This one has a lip, this is an armored gasket. Again, as I said, the style 90 coupling is very popular in gas applications where sometimes you want to maintain electrical contact and this armored gasket, this lip here, gives a little bit more rigidity, it also creates a contact with the pipe, a metal to metal contact, so this is how an armored gasket looks like on a style 90 coupling. As I mentioned, this is the exact same gasket that is usually style 38 coupling also. But remember, that’s not the case with a style 65.
This is a style 90 compression coupling elbow. Again, it looks exactly like a regular coupling; instead, it’s just in a 90° elbow shape. The same thing, armored gasket, a retainer cup goes like this, and I’ve shown you how to assemble it. Take it out, slide your pipe in, measure how far it has to go, leave about an inch room, put the gasket, and it’s better you put it on a vise, and then you use a torque wrench and tighten it to that required torque and that’s how you get a compression coupling.
Remember, other than the universal coupling, which has a lock ring, the elbow, the regular coupling, the male adapter does not prevent axial pullout. This one will create a seal and will hold the pipe to some extent but if there’s a lot of axial force, then it can pullout.
This is a style 90 compression male adapter. As I showed you for the style 65, it allows you to take a threaded connection and make a compression coupling out of it. This has a cap on it, but this is a male thread and you can thread it onto any coupling, any 3000 pound, any 2000 pound, or threaded coupling and then the other end now becomes a compression coupling, which is exactly like the other ones. This also has a retainer cup and a gasket, and the installation is exactly the same. The male adapter allows you to convert any regular threaded connection into a compression fitting.
In summary, Dresser offers a line of compression couplings. These are available in sizes of up to 2 inch nominal pipe. This is a style 90 compression coupling; this is a style 90 universal compression coupling. The only difference between a universal and a regular coupling is that the universal coupling has lock rings and it prevents from the pipe pulling out. This is the style 90 compression elbow, and this is a style 90 male adapter. Once again, if you compare it with the style 65, you can see it’s much more heavier, much more beefier connection. Style 90 coupling are rated for 300 pound service, it’s also very popular in gas service because of the armored gasket. A style 90 coupling, universal coupling, can be used on a PVC pipe or a PE pipe as long as the size matches. You may have to use a stiffener.
- Asif Ehtesham