Piping: Chapter 4
Connecting Pipe
In this module, we will learn about methods to connect the pipe. The methods that we are going to learn are as follows:
- Pipe connection
- Threading
- Flaring
- Swaging Skip to quiz!
Pipe Connections
After bending the pipes, we use pipe connection such as fittings to increase length of the pipe. A pipe fitting is used in plumbing systems to join multiple pipes of the same size or different sizes. Fittings are connected to threaded end of pipes.
We use pipes running over long length for carrying fluids. Think about a water supply line that transfer water from buildings water tank to our home. The pipes carrying fluid need to be supported so that they don’t break due to weight of fluid inside and weight of pipe itself.
Pipe hanger is a type of clamp that is used to support the pipe. The major functions of pipe hangers are to guide, tie up, and support load. The pipe should be supported every four feet with pipe hanger.
As seen in the video, we can easily clamp the pipe along wall or ceiling using hangers. We need to place the clamp around the pipe and drill through the two holes on the pipe clamp. Once this is done, we have to just screw the clamp.
Threaded Piping
Recall that Threaded piping is used to connect fittings on the threaded end of pipe. Threads are grooves cut on the periphery of the pipe. They prevent the two connected objects from pulling apart.
As seen in the video, many pipe threads including black, galvanized, and PVC are tapered. Tapered thread is smaller on the end and gradually gets bigger as it goes up the pipe. As fittings are tightened to this threads, connection becomes tighter, but not liquid-tight as there is small space between the threads.
A liquid-tight connection does not leak out after longer usage. Thread sealants are used to get a liquid-tight connection. Teflon tape or liquid thread sealants, also known as pipe dope, are used to seal the space in between the threads.
To make a sealed connection using only a teflon tape, first clean the threads to remove dirt. Then wrap the tape clockwise 2-3 times tightly on threads. Connect the fitting completely by using a ratchet or pipe wrench.
We can also make sealed connection using the teflon tape and pipe dope. First wrap the tape around the threads and then apply pipe dope. This is more efficient than just using the teflon tape.
The pipe dope will dry over time and expand slightly. This will create an liquid-tight seal between the pipe and the fitting.
Flaring
Flaring means to gradually widen the end of a pipe at an angle. Flared pipe is used to connect two pipe using flaring nut and fitting.
A flaring nut is already installed in the end that we will widen. Flaring nut is used to connect the threaded ends of connector.
To connect the the flared end of tube to another tubing, flare fitting is used. A flare fitting has both the ends threaded. One threaded end of the fitting is connected with flaring nut. The other end is used to connect threaded tubing.
We make use of flaring tool to flare or widen the end of a pipe. Flaring tool consists of two main components:
Die Block, and
Yoke
Let us have a look at each of them.
Die block is a metal bar with holes. These holes are provided for fitting standard pipe sizes ranging from ⅜ inches to ⅝ inches. Die blocks hold the pipe while flaring the pipe using wing nuts.
A yoke is a ‘U’ shaped metal piece that has a screw and handle. The cone part of the yoke is pressed over the end of the tube to be flared. As you turn the handle, cone moves towards pipe end.
When the cone is pressed into the pipe end, it shapes the soft metal into the 45° flare end. Let us look at how to use a flaring tool.
Place the flare pipe end out against the fitting, ensuring that the flare sits fully on the fitting. Tighten flare nut to fitting.
Swaging
Swaging is increasing the diameter of tubing over a short length. Unlike flaring, swaging does not widen the pipe end at an angle. A swaged tubing has an enlarged end that allows you to fit another tubing inside the swaged tubing.
The tool used for creating enlarged end of tube is called a swaging punch. As the swaging punch is hammered into the pipe end, it enlarges the end of the tube. This enlargement depends on the shape of punch.
Swaging punch has a series of steps to shape a tube in six different sizes. We can shape the pipe in diameter ranging from 3/16 inches to ⅝ inches using swaging punch.
Recall that die block is used to hold the pipe during flaring an end of pipe. You also need to hold the piping while swaging. Die block firmly holds the pipe while hammering using swaging punch.
Recall that flare fitting and flaring nut is used to connect tubing after flaring the tube end. We don’t require fittings for swaging. Because once you fit one tube inside the other you can braze them. Recall that brazing is joining two metals by heating.
As seen in the video, hold the pipe securely in the die block. This makes hammering the swage punch easier. It also protects you from hitting your hand if the pipe slips from your hand. We need to hold the hammer by its end to get maximum force.
Insert the swaging punch inside the tubing. Make sure it is aligned perfectly straight. Strike the end of the punch with a hammer until the tube end is enlarged.
We then insert the enlarged tube into another tubing to make a connection. These two tubings are connected using brazing process.
Brazing process is similar to sticking two sheets of paper together. When we stick two sheets of paper, we apply glue to stick them together. We need to press the two sheets of paper together so that they stick firmly.
Similarly, to assemble tubing to swaged end of pipe, we will have to apply heat and filler metal. Filler metal acts as a glue. It fills the gap between the pipes to stick them.
As we heat the pipes, it starts to expand. This is similar to the pressing action done on the sheets of paper.
Teflon tape and pipe dope are used for connecting threaded pipes. Flared tubing is used to connect tubes using flaring nut and fitting. Swaged tubing can be inserted into other tubing and then brazed to form permanent joint.
Question #1: What is the function of pipe hanger?
Cleaning pipe
Connect pipe
Guide, tie up, and support pipe
Threading pipe
Scroll down for the answer...
Answer: Guide, tie up, and support pipe
Pipe hanger is a type of clamp that is used to support the pipe.The major functions of pipe hangers are to guide, tie up, and support pipe.
Question #2: What is used to fill the space in between the threads for a sealed connection. (select all that apply)
Teflon
Pipe dope
Nut
Washer
Scroll down for the answer...
Answer: Teflon, Pipe dope
Teflon tape or pipe dope, are used to fill the space in between the threads for a sealed connection.
Question #3: What is flared end of pipe?
A pipe having its end at an angle.
A pipe with large diameter at end
A pipe with closed end
None of theseScroll down for the answer...
Answer: A pipe having its end at an angle.
Flaring is gradually widening the end of a pipe at an angle. Flared end of pipe is used to create flare joint.
Question #4: What is installed in pipe for creating flare fitting?
Nut
Connector
Washer
None of these
Scroll down for the answer...
Answer: Nut
A flaring nut is already installed in this gradually widen end. Flaring nut is used to connect threaded ends.
Question #5: Which wing nut needs to be tightened first to hold the pipe in the die block?
No need to tighten the wing nut
Farthest from the pipe
Closest to the pipe
None of these
Scroll down for the answer...
Answer: Closest to the pipe
Tighten the wingnut closest to the pipe first. Then, tighten the far wingnut to hold the pipe firmly.
Question #6: When do you need to stop rotating the handle of yoke?
When cone is fully seated in the pipe end.
When cone is slightly touching the pipe end.
When cone is farthest from the pipe.
None of the above
Scroll down for the answer...
Answer: When cone is fully seated in the pipe end.
Tighten the wingnut closest to the pipe first. Then, tighten the far wingnut to hold the pipe firmly.
Question #7: Which one of the following is the tool used to create swaged tubing?
Swaging die
Swaging Punch
Claw Hammer
Flaring nut
Scroll down for the answer...
Answer: Swaging Punch
The tool used for creating enlarge end of tube is called a swaging punch. As the swaging punch is hammered into the pipe end, it enlarges the end of the tube.
Question #8: Which one of the following processes use brazing process?
Sweat fitting
Swaging
Threading
Flaring
Scroll down for the answer...
Answer: Swaging
Recall that swaged tubing are connected using brazing process