A merchant coupling is used to join pipes together in a straight-line run. They are used most often in low-pressure piping situations, like with water, oil, air, or gas lines. Merchant couplings typically do not stand up well in situations where high pressure is involved. These couplings are generally made of steel tubing and are most often found in carbon, galvanized, stainless or black.
Merchant couplings are often said to be little more than thread protectors. In reality, they are much more than that as they join together your pipe so that you can have long and continuous runs of pipe in various situations. Merchant couplings are best used in situations where 150psi or less is in use.
These couplings also work best in situations where temperatures are moderate. They also come in tapered or non-tapered styles. Where a solid and tight seal between two pipes is called for, then using the tapered style is best as it will form a tighter seal as it is screwed on. Straight-line merchant couplings are less likely to form the tight seal you may need. In the end, your merchant coupling will also need to be welded onto your pipe. Most merchant couplings will come with a chamfered end to help compensate for the welding necessary to your coupling.
Any time that strength is needed to continue straight line runs is where you want to use merchant couplings. Since merchant couplings are made of stronger steel rather than malleable steel their use is needed rather than some other types of coupling.
At Detroit Nipple Works we have many years of experience in the manufacture of merchant couplings. Let us help you to determine which type of merchant couplings will be best for your particular use. Don’t make the error of using the wrong type of pipe coupling that will not stand up to your application. As they always say: do it right the first time. It is our goal to help assure that you have the right pipe nipples on your job.
Contact us for all of your fittings, pipe nipples, pipes and tubing or valves. We have the experience to help assure that your job stands out as one done right.