Robobrew Question - what's the center pipe for?

[TwoHeadsBrewing]

I'm coming from a 3-piece all grain setup, so I'm used to a normal mash tun with the false bottom. Everything on the Robobrew makes sense to me except that little center pipe. What's the purpose of this, and the stainless funnel piece that sits on top? Wouldn't the malt pipe work just fine if it were capped off, leaving just the malt pipe with a screen on the bottom?

Just saw this comment:

One word of caution on plugging the center pipe, if you end up with a truly stuck recirculating mash, you could end up dry firing the element and causing a potentially bigger headache. The center pipe is designed to try to ensure there is always wort on the element. Just something to consider. I agree it isn't the easiest design to work with, but I mash very thin with the Robobrew and throttle the recirculation so it keeps a small layer of wort just above the grain bed with just a trickle going down the center pipe.

So it sounds like a safety measure to prevent no wort in the kettle while the burners are on. Makes sense if you're recirculating the mash and leaving it unattended.

 

[verboten]

That’s what it’s for. And if you want any kind of efficiency, you need to recirculate. I try to keep my flow rate low enough that I don’t get any wort down the overflow anyway, but that’s how you get husks in your boil.

 

[TwoHeadsBrewing]

Now after brewing once, I'm still stumped about this thing. If you happen to have a stuck mash, the wort level is going to get up to the holes for the lifting handle and flow through those. An even better idea than this center tube would be some small holes along the top of the malt pipe, just like what's in the bottom. Then just remove that center thing entirely. I might just do that myself and cap the bottom with a stainless bolt.

 

[mdrose]

I have a robobrew V3 and also a bit confused about this center pipe. But you have to remove the black cap from the top after you mash in. Then If the mash gets stuck on the bottom screen and the worst level rises, it will go down the middle tube (open) and not rise to the level to reach those holes for the handle.
I have actually often just left the rubber cap on the tube during mash recirculating to keep grain and husks from getting down into the bottom area. I presume that having your wort flow fully though the grain bed and to the bottom pump is going to provide better extraction efficiency. When your wort goes down the tube, it’s essentially by passing filtering through the grains.Right? Anyone have any comments on my assumption?