Hello, everyone.
This is Enta.
Starting today, I'm heading to Mie to assist the dewatering drilling crew!
Long live the labor shortage!
But that's beside the point.
Failures in Drainage Boring Operations
The most troublesome thing about drainage drilling is when the pipe won't go in (lol).
Normally, it would fit. Normally...
However, while the PVC pipes are the same in some areas, there’s a catch!
↑This is it!
This is a pipe fitting used to connect two perforated pipes.
To connect them, plug them into each other.
Generally speaking, the perforated pipes used in dewatering borehole construction are either VP40 or SGP50A.
The minimum inner diameter for a φ90 bore is 68 mm.
The outer diameter of the VP40 is 48 mm. When it is centered, the clearance is approximately 10 mm on each side.
Since the outer diameter of the pipe fitting is 57 mm, the maximum clearance is 11 mm.
When placed in the center, there is a gap of about 5 mm on either side.
In theory—on paper—it’s guaranteed to work!
But this isIn actual fieldwork, I don't go in there.
Even with a VP40 and a borehole diameter of φ90, the PVC pipe may actually come up with the casing (i.e., the PVC pipe falls out along with the casing).
Please look at the figure above.
The black part is the casing, and the gray part is PVC.
Red indicates clearance.
Debris and other stuff gets stuck in this red area!
Even with 10 mm of clearance on either side, it may still get stuck.
If the socket is only 5 mm wide, inserting it becomes an extremely difficult task.
No, no—it won't work because you haven't washed it properly! Are you really cleaning inside the holes thoroughly??
That's what the director says lol (Well, I was saying that too, lol)
It's enough. I wash it quite a bit.
Still, what's no good is just no good.
When it comes to offering food, I just can't help but do it.
Large gravel or, in some cases, backflow of sandy soil, etc.
Gas pipes like the SGP50A are the best option whenever possible. (It’s standard practice to thread SGP pipes.)
PVC would be fine, but I’d like you to machine it with left-hand threads.
The important thing here isThe threading is left-hand!
On Japanese drilling machines, counterclockwise rotation is considered forward rotation.
Since there is a risk that the fastener will loosen and come off if it isn't left-handed, left-hand threads are standard practice.
See you later.
Tips for Drainage Drilling | Preventing Clogging and Jamming
