Winder Expansion & Contraction Cylinders: 25MPa Industrial Hydraulic Solutions for Steel Reeling

Product Overview
The coiler expansion cylinder consists of a double-acting hydraulic cylinder combined with a rotary joint. Its main function is to expand and contract the drum diameter of coilers or uncoilers by extending and retracting the cylinder during rotation.

For precise stroke control, a displacement sensor can be installed, with an optional pressure sensor for accurate monitoring and control of push-pull actions. Two exhaust/pressure test ports are located on the top of the rotary joint, while each side has four inlet/outlet ports—two in use and the others sealed. The leakage port at the bottom must be connected to the return line to ensure smooth oil return and prevent external leakage caused by back pressure exceeding 0.5 bar.
A torque arm hole is provided beneath the rotary joint to fix an anti-rotation bar (floating positioning to avoid axial load). The flange surface must be perpendicular to the rotation axis, ensuring radial run-out ≤1 mm. Oil and leakage pipelines should be firmly fixed to avoid radial or axial forces on the rotary joint. For high-temperature hot-rolling coilers requiring cooling water, expansion cylinders with an integrated water rotary joint are available.

Key Features

・High-quality reciprocating and rotary seals; rotary joint with precision bearings
・Reliable operation, long service life, easy maintenance
・Over 1,000 units delivered worldwide in the past two decades
・Customizable bore size 100–900 mm, max. working pressure 25 MPa
・Unique clearance seal structure prevents heat generation, removes speed limits, and greatly extends rotary joint lifespan
・The mandrel expansion cylinder of the coiler can undergo dynamic balancing testing and adjustment according to customer requirements, in order to meet the specified balancing speed range (balancing cycle), balancing quality grade, and ensure that the residual unbalance complies with the customer-permitted eccentricity (residual centrifugal rate) standard. A dynamic balance test report will be issued accordingly.

Applications
Widely used in:
・Cold-rolling and hot-rolling strip coilers and uncoilers
・Construction machinery and injection molding machines
・Chemical processing equipment

In high-speed operations, traditional rotary joints typically adopt contact seals. The relative motion generates excessive heat at the sealing interface, causing premature wear, aging, and leakage, which significantly shortens service life.

Uranus has developed a proprietary clearance-sealed rotary joint, which relies on a precision gap between the rotor shaft and sleeve to achieve sealing. With no direct metal-to-metal or seal-to-metal contact during operation, it effectively avoids heat generation, removes speed limitations on sealing performance, and greatly extends service life.

The rotary joint is equipped with precision bearings, ensuring reliable performance. Over the past 20 years, Uranus has delivered over 1,000 expansion cylinders worldwide, applied extensively in cold- and hot-rolling coilers, uncoilers, sheet and strip processing lines, as well as construction machinery, injection molding, and chemical equipment.

The reel expansion and contraction cylinder comprises a double-acting sequential hydraulic cylinder and a rotary joint. The hydraulic cylinder regulates the expansion and contraction of the steel reel diameters by extending and retracting during rotation. To accurately display and control the stroke of the pressure cylinder, a displacement sensor can be integrated into the telescopic mechanism. Additionally, a pressure sensor can be installed if required to ensure precise monitoring and control of the telescopic push and pull movements.

Two exhaust pressure measuring joints are installed above the rotary joint, allowing for convenient gas venting from both chambers of the telescopic cylinder and real-time detection of oil pressure in these chambers. For easy use, four oil inlet and outlet ports are positioned on both sides of the rotary joint's horizontal axis. You can select any two ports for use, while the remaining two can be sealed with sealing screws.

Uranus expansion and contraction cylinders are equipped with high-quality reciprocating and rotary seals. Precision bearings are installed in the rotary joint, ensuring reliability and long service life. In the past 20 years, we have developed and produced over a thousand expansion and contraction cylinders for global users. These cylinders are widely used in both cold and hot rolling, plate and strip reeling machines,as well as many engineering machinery, injection molding machinery and chemical equipment.

Uranus has produced expansion and contraction cylinders with diameters ranging from a minimum of 100mm to a maximum diameter of 900mm. In addition, they have a maximum operating pressure of 25MPa. These cylinders can be custom-designed and manufactured to meet specific customer needs or can be produced based on drawings provided by customers.

1.Expansion and contraction cylinder (two cylinders in series) Large cylinder diameter: 900; rod diameter: 360; stroke: 17;
Small cylinder diameter: 850; rod diameter: 360; stroke: 77
Built-in displacement sensor
Operating pressure 10MPa; test pressure: 15MPa
Rated speed: 450r/min

2.Reel-Expansion-and-Contraction-Cylinders14.jpg
Reeler and roller expansion and contraction cylinder diameter: 250; rod diameter: 110; stroke: 113.5; buffer stroke: 30;
Built-in displacement sensor
Operating pressure 14MPa; test pressure: 21MPa
Rated speed: 650r/min

3.Expansion and contraction cylinder (two cylinders in series) Large cylinder diameter: 760; rod diameter: 315; stroke: 20;
Small cylinder diameter: 680; rod diameter: 315; stroke: 75
Built-in displacement sensor
Operating pressure 12MPa; test pressure: 21MPa
Rated speed: 450r/min

4.Rotary telescopic cylinder diameter: 320; rod diameter: 180; stroke: 74;
Built-in displacement sensor Rotating joint jacket Cooling water jacket
Operating pressure 21MPa; test pressure: 25MPa;
Rated speed: 3800r/min