These are "ten slot" screens, which means that the slots are 0.010" wide. Apparently this is a pretty fine screen, but it's necessary because the material at the bottom of my well has a lot of very, very fine sand that will get past larger slots. These particular screens were made by Alloy Machine Works, down in Texas.
Here's a look down the inside length of a screen:
In the picture above, you can see two other screens underneath the one propped on the tailgate. Each screen is 5' long, so I'll have 15' of screens total, after they are welded together. Three screens is what Boyd said I had room for in this aquifer. I could have gone with just one and saved some money, but the more screen surface area you have, the less time it should take for the aquifer to re-fill the well after you've pumped some water out. In theory anyway. I tend to over-build things regardless, and this seemed like cheap insurance so I went with all three screens.
The screen slots are narrowest on the outside, and open up towards the inside; this ensures that sand and other materials that get past the outside opening, won't get stuck. If any particles do make it inside, they'll just keep going and eventually fall to the bottom of the screen. You might be able to see what I'm saying, by comparing the first picture above with this one:
This doodad is what is known as a "K packer"...
The K-packer is used (if I remember this correctly) to attach\seal the well screen to the bottom of the well casing. I think we've got it upside down in the picture above, but presumably the well screen is welded to one end of the K-packer, and then it's just slid down the entire well casing until it gets close to the bottom. The very bottom of the well screen has a flat cap that gets welded on to seal that end. So the only way for water to get into the well itself, is through the well screen.
We were there this morning when Boyd fired up his rig and started pumping compressed air down the hole. This is what came out when he did that:
If I can judge correctly (based on my extensive, two-hour-long well-flow-estimation lesson), the flow in the above picture is not 11gpm as I reported in my last post. I found this quite interesting, but the flow rate (yield) actually can change at different depths within the aquifer. Near the top of the aquifer (I think) it was near 11gpm, but the material there was very, very fine sand, which Boyd was trying to avoid. So he was hunting around (up and down, I mean) for good yields at other depths in the aquifer, but with coarser material. Based on his comments I guess gravel is the best because you get good water flow through the gravel, and gravel won't plug up your screens. However, he was quite confident that in the end he'd get that 11gpm out of our well. Sound good to me!
Finally, the crew keeps a can of cake frosting on hand in case they need a quick sugar pick-me-up: