ROTELMANNDN-4-STwo-Way Manual Ball Valve, DN4 Bore, M16x1.5 Ports, Quarter Turn Shut-Off

Product Description

What this part is

A Rotelmann DN-4-S two-way manual ball valve with a DN4 nominal bore and M16x1.5 threaded ports. It is the small isolating valve used on hydraulic, lubrication, grease and pressure-gauge lines — a quarter turn takes it from full flow to shut, and in the open position the through-bore is straight, so it adds very little pressure drop to the line.

Decoding the order code

Rotelmann — German maker of small-bore ball valves and fittings for hydraulic and lubrication systemsDN 4 — 4 mm nominal bore. This is the flow path, not the threadS — Rotelmann build / body variant designationM16x1.5 — metric port thread, the standard DIN 2353 light-series thread for 10 mm outside-diameter tube

What these specs mean in practice

DN4 and M16x1.5 describe two different things, and both have to match. The bore governs flow; the thread governs what fitting or tube coupling screws in. A valve with the right thread but the wrong bore will fit and still throttle your circuit.

Because it is a ball valve rather than a needle valve, it is an on/off device, not a metering device. Partially opening a ball valve to trim flow wears the seat and gives no repeatable setting; use a needle or flow-control valve for that job.

At DN4 this is characteristically a gauge isolator, test-point shut-off or a branch isolation on a lubrication manifold — a place where you need to shut one small line without draining the system.

Published specifications

Type: two-way manual ball valve, shut-offNominal bore: DN 4 (4 mm)Ports: M16x1.5 metric threadPorts count: 2, straight throughActuation: manual, quarter turnApplications: hydraulic, lubrication and gauge linesOrigin: Germany

Quantity and configuration

Sold as one valve. Stock came in as a bag of five, so the individual valves are loose rather than separately boxed. No fittings, tube couplings, adaptors or mounting hardware are included.

Fitting notes

M16x1.5 is a parallel metric thread and seals on a cone or O-ring at the fitting, not on the thread flanks — do not treat it as a tapered pipe thread and do not rely on sealant. Support the valve body when tightening tube couplings so the torque does not go through the ball seat. Leave room for the handle to swing a full quarter turn before you clamp the line down.

Interchange guidance

Other DN sizes in the Rotelmann range use the same style of body with different bores and port threads — related sizes, not substitutes. Any replacement has to match both the DN bore and the M16x1.5 port thread; matching only one of the two is the usual cause of a wrong-part order on small-bore valves.