Antminer S19 / S21 Dual 120 mm to 6-Inch Offset Shroud — Wide Base

Description

Offset duct shroud for the Antminer S19 and S21: the collar moves, the fans do not

An offset duct shroud solves the problem every racked Antminer eventually creates: the duct wants to leave straight off the centre of the fan face, and there is a shelf, a wall or the next machine exactly there. This shroud captures both 120 mm exhaust fans of an S19 or standard S21 as usual, then puts the 6-inch collar off the fan centreline so the duct exits where the room actually has space.

It sits on the wide 260 mm base plate, and in a rack that pairing is the point: the broader flange bears across the exhaust face and gives the shroud something to push against when a duct pulls sideways rather than straight back, which is exactly what an offset outlet does to the mount.

What it fits

• Antminer S19, S19j, S19j Pro, S19 XP — dual 120 mm exhaust panel
• Antminer S21 and T21 standard chassis — dual 120 mm exhaust panel
• Any dual 120 mm exhaust face on a 120.0 mm pitch and 105 mm screw square
• 6-inch flexible duct over the offset collar

If the clearance problem is real but the wide flange is itself what will not fit, the standard-base offset shroud puts the same offset outlet on a 250 mm plate. If nothing is in the way, the centred plain wide-base 6-inch shroud is the shorter, simpler part. And if the obstruction is further down the run rather than at the machine, solve it with the 6-inch 45-degree elbow instead.

How it goes on

1. Decide which way the duct needs to leave before you lift the shroud on, and orient the offset accordingly.
2. Seat the flange over both fans so the eight slots line up with the fan screw holes.
3. Fit M4 screws with a 9 mm or larger flat washer under each head, or reuse the miner’s large-head fan screws. There is 8.06 to 10.88 mm of driver clearance at every hole.
4. Slide 6-inch flex duct over the collar, past the retention bead onto the sealing band, and support it at the first bend.

Why an offset outlet beats an elbow at the machine

The obvious way to dodge a shelf is to bolt a centred shroud on and hang a 90 degree elbow off it. That works, but it adds a joint and a hard turn in the worst place: immediately downstream of the fans, where the column is still the shape the blades left it. Moving the collar inside the shroud does the same job with no extra joint, steering both fan columns onto a throat that already sits where you need it.

• Puts the duct where the rack has room without adding a fitting at the machine face.
• Steers both fan columns onto the offset throat inside one continuous plenum wall.
• Removes a joint from the hottest, most turbulent part of the run, and a place to leak with it.
• Carries sideways duct load on a 260 mm plate rather than on four screw slots.
• Keeps all eight fan screws driver-accessible so the shroud comes back off in a rack.

Specifications

Open source — the awkward variants are free too

Offset outlets are the kind of part nobody stocks, because every rack is awkward in its own way. D-Central Technologies’ answer is to draw them and hand the drawings over: the shroud line is released under CC BY-SA 4.0 at the 3D models download center, free to print, modify and sell. The card for this model links the ZIP, with the STL, the licence and the installation and safety guide inside.

Buying here gets the finished part in black or orange PETG, built to order in Montreal, Quebec. The D-Central fund page keeps that release work funded.

Works with

• Antminer S19 / S21 Offset Shroud — Dual 120 mm to 6″
• Antminer S19 / S21 Dual 120 mm to 6-Inch Shroud — Wide Base
• 6″ 45° Duct Elbow
• 6″ Duct Coupler
• 6-Inch Flex Duct Window Vent Port

Offset at the machine, gentle turns down the run, a port at the wall: that is the whole install. See the whole D-Central shroud and ducting system.

Frequently asked questions