30 Ton Hydraulic Cylinder

To press exactly 30 t the Ø160 mm piston needs 146.3 bar, leaving 13.7 bar for losses in valves and hoses — a 9.3 % reserve, just under the 10 % many designers keep. If the load estimate is uncertain, step up to Ø200 mm at 160 bar or Ø160 mm with the 250 bar option; both give 51.3 t. At 250 bar Ø125 mm is enough, but its 4.3 % reserve is thinner still.

Counted in US tons, both standard choices have more room: 21 % for Ø160 mm at 160 bar and 15 % for Ø125 mm at 250 bar. At 100 bar a 30 t job already takes Ø200 mm, the top of the standard series. The 210 bar lines are a reference; Fenitsa cylinders run at 160 bar, or 250 bar as an option. Every size: hydraulic cylinder sizes.

Many 30 t jobs only push. If yours also pulls — stripping a punch, drawing a part, dragging a tool back against friction — the annulus must deliver the force. At 160 bar only the Ø200 mm bore does it, with either rod; at 250 bar Ø160 mm does, pulling 35.0 t with the Ø90 mm rod.

On a fixed pump flow the rod comes back φ = 1.46 times faster than it goes out, which suits press work: a controlled pressing stroke and a quicker return. Many presses add a fast, low-force approach by switching pumps or valves; the cylinder simply follows the flow it is given, within the 0.5 m/s piston speed limit.

This example is pinned at both ends — rear clevis and rod eye, mounting factor 1 — with free length = 2 × stroke + an assumed 400 mm dead length. Buckling load F_k = π² × E × I / L_k² with E = 210,000 N/mm², divided by the usual safety factor of 3.5.

At 1,800 mm only Ø200 / Ø125 mm passes; it then needs just 94 bar for 30 t, so the bigger cylinder runs at an easy pressure. The alternative is a front flange with a guided rod end, which shortens the buckling length — see long stroke hydraulic cylinders.

A 700 bar jack-type cylinder gets 30 t from about Ø73 mm. For a press, force is only half the story. Most jack-type cylinders return by spring or load — too slow and too weak to pull a tool out of the work — while a double acting industrial cylinder returns under oil pressure: Ø160 / Ø90 mm pulls 22.4 t.

Fenitsa builds the industrial type, rated 160 bar with a 250 bar option.

Say whether 30 t is needed on push, pull or both — that decides between Ø160 and Ø200 mm. A straightening-press cylinder with a centre trunnion might read FDH-160-600-CTM-NS-CR (600 mm stroke, NBR seals, Ck45 chrome rod), with the rod diameter stated. Details: FDH type hydraulic cylinders, double acting cylinders.