Industrial Presses ‒ Guardian of the Pressure

No chance for unwanted pressure buildup

A proven standard sealing system is predominantly used in a plunger cylinder. Large diameters and high system pressures with long strokes are the norm here. The pressure-relieved Merkel® Omegat primary rod seal takes on the important task here of preventing excessive pressure buildup in the space between the primary and secondary seals due to drag oil. A possible risk of extrusion for both sealing elements and thus failure of the sealing system is averted.

Typical application fields: Metal forming presses; Chipboard presses; Tube forming presses.

Typical operating conditions:
Rod Diameter: 700 mm
Movement: Linear, downward stroke
Pressure: 30 MPa
Speed: Loaded: 0,02 m/s; Load-free: 0,5 m/s
Stroke: Loaded: 400 mm; Load-free: 2500 mm
Medium: Mineral Oil

When things get hot and dusty

If environmental influences such as dirt and liquids or radiant heat play a role, a special wiper made of PTFE is used in the proven standard sealing system for the plunger cylinder. The double wiper Merkel® PT2 with housing-enclosing geometry reliably protects the sealing component behind it from contamination. This sealing solution also allows the cylinder to be arranged with the rod extending upwards.

Typical application fields: Chipboard presses; Short-cycle presses; Stone and ceramic presses; Up-stroke presses.

Typical operating conditions:
Rod Diameter: 700 mm
Movement: Linear, upward stroke
Pressure: 30 MPa
Speed: Loaded: 0,02 m/s; Load-free: 0,5 m/s
Stroke: Loaded: 400 mm; Load-free: 2500 mm
Medium: Mineral Oil

For water-based hydraulic fluids

If flame-retardant hydraulic fluids (HFA) are used to operate a plunger cylinder, the standard sealing system is trimmed for hydrolysis resistance. This means that only sealing elements made of elastomer or PTFE materials are used. Even the static cover seal is designed as an O-Ring with a PTFE backup ring.

Typical application fields: Forging presses; Metal forming presses; Particle board presses.

Typical operating conditions:
Rod Diameter: 700 mm
Movement: Linear, downward stroke
Pressure: 30 MPa
Speed: Loaded: 0,02 m/s; Load-free: 0,5 m/s
Stroke: Loaded: 400 mm; Load-free: 2500 mm
Medium: Water Emulsion (HFA)

For shortest control strokes

During short strokes of a plunger cylinder, no sufficient oil film is built up under the sealing edges and the guide elements. Suitable seal materials from our portfolio and special guides are the answer to this type of poor lubrication. The convex geometry of our Merkel® Guivex guide facilitates the intake of operating medium for sufficient lubrication of the guide element even with the shortest strokes.

Typical application fields: Continuous particleboard presses, Fine blanking presses.

Typical operating conditions:
Rod Diameter: 400 mm
Movement: Linear, upward stroke
Pressure: 26 MPa
No. of cycles: 60/min
Stroke: 2 mm up to 10 mm
Medium: Mineral Oil

Optimized V-Packing Set

The modern polyurethane pressure ring in the Merkel® ES81 roof collar set scores points in several ways:

• Increased sealing effect
• Additional static sealing edge against the ingress of air
• Favorable friction behavior
• High resistance to gap extrusion

Typical application fields: Down-stroke presses; Short cycle presses.

Large diameter, rough operation

Hard usage often goes hand in hand with a highly stressed surface of the cylinder rod. This is where a Merkel® V-Packing Set V1000 shows its strength. The seal set is resilient to scratches and wear and still provides good gap bridging even at high pressure and increased guide clearance. If open installation and tolerance to dust & dirt are also on the to-do list, the re-adjustable Merkel® V-Packing Set V1000 is the first choice.

Typical application fields: Large-size presses.

From old to new

The modern Merkel® cassette solution is a potential replacement for older V-packing sets in plunger cylinders. The driving forces for a retrofit are:

• Higher sealing performance requirements
• Favorable friction characteristics for greater control accuracy, short cycle times, and high speeds
• Constant long-term behavior
• Easier installation

Typical application fields: Retrofit; When requirements change.

Long strokes under control

Under normal operating conditions, the standard sealing system for a differential main cylinder consists of the most advanced components in the Freudenberg Sealing Technologies product portfolio. They offer features such as

• Merkel® Omegat OMS-MR PR primary seal for maximum extrusion protection
• Merkel® T20 polyurethane secondary seal for low friction and minmal residual oil film on the rod
• Polyurethane double wiper with long service life
• Merkel® Guivex guide bands for highest loads

Typical application fields: Downstroke presses; Metal forming presses; Bending presses; Working cylinders.

Typical operating conditions:
Rod Diameter: Rod: 200 mm; Piston: 250 mm
Movement: Linear, downward stroke
Pressure: Rod: 16 MPa; Piston: 30 MPa
Speed: Loaded: 0,01 m/s; Load-free: 1 m/s
Stroke: Loaded: 200 mm; Load-free: 1600 mm
Medium: Mineral Oil

Taking the scare out of rough conditions

In order to avoid metallic contact between the moving and static parts, large gaps are generally used, especially under harsh ambient conditions, high operating pressures or pressure peaks. The sealing system of a differential cylinder must therefore be particularly robust and bridge large sealing gaps. A Merkel® ES61 V-packing set with bronze pressure ring masters these challenges.

Typical application fields: Baling presses; Scrap presses.

Typical operating conditions:
Diameter: Rod: 200 mm; Piston: 280 mm
Movement: Linear, horizontal stroke
Pressure: Rod: 10 MPa; Piston: 30 MPa
Speed: 0,3 m/s
Stroke: Up to 10,000 mm
Medium: Mineral Oil