00:00 |
Now that we've discussed flexible hoses and couplers, we need a way of securing them to our other fittings, hardlines and sections of pipe in our plumbing systems.
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00:08 |
And this is most often achieved using hose clamps.
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00:11 |
With all the variations of plumbing components being attached, there are naturally a lot of different types of hose clamps for different jobs.
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00:19 |
But in the end of the day they all have the same function, which is applying radial tension to increase the friction force and hold the hose in place.
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00:28 |
For clarity, the friction force is the resistance to relative motion of the contact surfaces and is proportional to the force holding the surfaces together.
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00:37 |
These hose clamps are also commonly referred to as constant tension clamps, which describes the even amount of tension around the circumference of the clamp as it applies even compression to the hose.
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00:48 |
Let's dive in with the most simple hose clamps, which are most often used for small diameter hose like vacuum lines or coolant overflow.
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00:56 |
These are single piece spring hose clamps that are made with the default inner diameter smaller than the outer diameter of the hose.
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01:04 |
There are two tabs that when squeezed together increase the inner diameter, allowing the clamp to be installed over the end of the hose.
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01:12 |
When the tabs are released, the clamp will relax back to its original position, applying pressure to the hose.
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01:18 |
These are available in different sizes, structures, materials and appearance but they all work on the same principle.
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01:25 |
Another relatively simple form of hose clamp is the crimp style.
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01:29 |
Also referred to as push lock clamps due to their common use with these types of hose and hose end.
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01:35 |
These have a metal outer ring with a raised section and often smooth inner surface to protect the hose.
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01:42 |
After the hose is in place, these are crimped together and tightened to clamp the hose.
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01:47 |
While these can be removed, they can't be reused but they aren't too expensive so we just need to have a few spares.
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01:54 |
The next form of hose clamp we'll discuss is maybe the most commonly used across all the majority of hose sizes for all our plumbing systems, and that's the worm gear hose clamp.
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02:05 |
The term worm gear refers to the helical threaded screw integrated into the clamp body.
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02:10 |
This meshes with the slots in the band of the clamp, which is split and can slide over itself.
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02:17 |
So, when the gear is turned, it changes the circumference and therefore the diameter of the band, allowing it to apply pressure over the hose.
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02:25 |
Using the mechanical advantage of the thread, it's possible to apply significantly more compression to the hose than the force required to rotate the worm gear and tighten the clamp.
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02:35 |
Past the basic function, there's quite a bit of variation that isn't as commonly known besides the different materials, colours and sizes.
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02:43 |
The most basic variation is what we've just described, where the band is a single layer so the slots protrude through the entire band.
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02:52 |
While these can work fine, the inner surface of the band can be abrasive, as the slots act like a cheese grater and can permanently damage the surface of the hose.
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03:01 |
The fix here involves using a multi layer band where the slots are only on the outer surface and the inner surface in contact with the hose is smooth.
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03:10 |
Alternatively, the inner surface may also feature beads to concentrate the pressure and help with clamping security.
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03:18 |
Rounded edges on the inner band are also a requirement for clamps used with silicon hose and couplers to avoid cutting into the hose.
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03:26 |
Another variation includes a corrugated section of the outer band, providing a spring effect.
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03:32 |
This helps the clamp expand and shrink with the changing heat of the components, while maintaining constant tension.
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03:38 |
The terms Murray clamp and Jubilee clip are often used to describe worm gear hose clamps of different varieties.
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03:46 |
But these are really just companies or brands that have been major suppliers of these parts for a very long time.
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03:52 |
The final type of hose clamp we'll discuss is a T-bolt style clamp.
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03:56 |
This makes use of a T-bolt, as the name suggests, with one end connected to the band.
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04:01 |
The bolt runs through a nut secured to a separate part of the band.
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04:05 |
When the bolt is rotated, the nut is forced along the length of the bolt, changing the distance between them and therefore the internal diameter of the band, allowing pressure to be applied to the hose.
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04:16 |
In using a bolt and nut, the threads have more integrity and therefore can be tightened more than a worm gear hose clamp.
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04:23 |
We just need to be careful not to over tighten the clamp and damage the hose or pipe inside it, as the pressure applied is not distributed as evenly as that of a worm gear style hose clamp.
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04:35 |
That covers the main forms of hose clamps, so let's recap the main points.
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04:40 |
Simple spring style hose clamps are commonly used for small diameter hose, as well as some bigger sections.
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04:46 |
These are cheap and easy to use but we can't adjust the clamping force.
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04:51 |
Worm gear hose clamps are probably the most common and available with a lot of subtle variations that can make significant differences.
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04:59 |
What is important to keep in mind is how the clamp could damage the surface of the hose.
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05:04 |
T-bolt clamps allow for more force to be applied so are generally a more secure connection, these can be over tightened easily though and the pressure is not evenly distributed.
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05:14 |
So, we need to be careful not to damage the plumbing inside.
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