Drop and 45° outlet (manifold) on a compressed-air network

A drop starts at the branch, runs down in aluminium pipe and ends in a 45° outlet that integrates the isolation valve and the drain. Air is taken from the top of the drop and condensate is drained at the bottom: water collecting at the low point is removed, and drier air goes to the tools.

Why this geometry

In a compressed-air line, condensation water settles and migrates to the low points. A drop is precisely a low point. The rule:

Air takeoff upward (outlet at the top of the drop) → the air carries less liquid water.
Drain at the low point → the condensate that accumulates is removed.

CAGI (handbook, ch. 4) sets the same rule: take air from the top of the header (condensate stays at the bottom of the pipe) and plumb drip legs from the bottom, where condensate flows down by gravity. It also recommends 45° elbows that introduce flow tangentially, which reduces turbulence and pressure drop.

That is exactly what the 45° outlet with drain achieves: the working outlet leaves at 45° upward, and the drain sits below the manifold.

The 45° outlet: one part, three functions

Part	Outlets	Integrates
45° outlet with valve — single (89.885)	1	Isolation valve + drain
45° outlet with valve — double (89.886)	2	Isolation valve + drain
45° outlet without valve (89.841 / 842)	1 or 2	Drain only
Wall manifold (89.844 / 845 / 847)	3 / 4 / 6	Station bank (bare — add valve + drain)

The “with valve” outlet is the complete drop station: a single part closes the drop (ball valve), serves the tool and drains the water.

Assembly

Remove the nut, clamping ring and identification ring from the fitting that will receive the outlet.
Insert the 45° outlet into the fitting and tighten it.
Align the valve and the outlet, then tighten the locking (Allen) screw.
Fix to the wall (the outlet has a bolt-hole plate).

Key point — A drop drain removes the liquid water accumulated at the low point; it does not replace the dryer (water vapour) or the filters (oil). For automatic draining of low points and receivers, see the condensate drains.

Size and complete

Drop diameter is computed from the flow of its tools, keeping the pressure drop from the header to the station under 1 psi (CAGI benchmark) — see the network estimator, which automatically adds the 45° outlet (valve + drain) to the bill of materials. For air quality at the stations, see ISO 8573-1 classes and choosing a filter and the water-in-the-network diagnosis.

References

CAGI — Compressed Air & Gas Handbook (7th ed., 2021), Chapter 4 — air taken from the top of the header, drip legs from the bottom, tangential 45° elbows, drop pressure drop ≤ 1 psi
EQOfluids — technical manual (wall manifold and 45° outlet with drain assembly)
Branching off the line — saddle branch and branch
Supports and fixing the pipework

Frequently asked questions

Why take air from the top of the drop?

Because condensation water falls to the low point of the drop. By taking air upward and putting a drain at the low point, you send drier air to the tools while removing condensate. This is the gooseneck / high-takeoff principle.

Does the EQOfluids 45° outlet already contain a valve and a drain?

Yes. The 45° outlet "with valve" (89.885 single, 89.886 double) integrates the ball isolation valve AND the manual drain. A single part closes the drop, serves the tool and lets you purge accumulated water. The "without valve" version (89.841/842) has the drain only.

How do you serve several stations in one spot?

Use a wall manifold with 3, 4 or 6 ports, fed by the drop and fixed to the wall. It is bare (no integrated valve or drain): add an isolation valve upstream and a drain at the low point.

Do I still need a dryer and filters if I drain the drops?

Yes. The manual drain removes accumulated liquid water, but not water vapour (the dryer's job) or oil (the filters' job). A drop drain complements the central treatment, it does not replace it.