Rotating unions – find manufacturers and suppliers

Rotating unions are mechanical components that enable the transfer of fluids or gases between a stationary and a rotating component.

They are used in machines where components rotate but must be supplied with media at the same time, e.g. in machine tools or packaging machines.

Below you will find an overview of how they work and the types of rotating unions, as well as an overview of their areas of application and a brief overview of maintenance and fault prevention:

How rotating unions work:

Basic principle:

1. A stationary supply line feeds the medium (e.g. oil, water, air) into the rotating union.
2. The rotating union contains seals and bearings that enable low-friction rotation and the passage of the medium.
3. The medium is transferred to the rotating outlet pipe.

Components of a rotating union:

1. Housing: This contains the internal components and ensures stability.
2. Rotor/shaft: This connects the rotating element to the machine.
3. Seals: They prevent leaks between the media chambers.
4. Bearings: Enable low-friction rotation of the shaft.
5. Inlet and outlet: Inlet and outlet for media such as liquids and gases.

Sealing technology:

1. Sliding seals: High tightness, low wear.
2. Ball seals: Suitable for high pressures.
3. Labyrinth seals: Reduce the ingress of impurities.

Types of rotating unions:

Rotating unions are available in various designs, depending on the medium and application:

1. Simple rotating union for water, oil, air.
   Used for cooling and lubrication.
2. Multi-channel rotary feedthrough designed for several media simultaneously.
   Used in machine tools and robots.
3. Hydraulic rotary feedthrough for high pressures for passing hydraulic oil.
   Used in presses and construction machinery.
4. Pneumatic rotary union for the passage of compressed air.
   Used in packaging machines.
5. Hybrid rotary feedthrough as a combined feedthrough for different media and electrical currents.
   Used in automation technology.

Use of rotary feedthroughs:

Rotating unions are indispensable in many industrial sectors. Here are some typical applications:

1. Machine tools:
Supply of spindles with coolant or lubricants.
Use in CNC milling machines and lathes.

2. Packaging and printing industry:
Rotating printing rollers with supply lines for a temperature control system.
Packaging machines with rotating filling systems.

3. Robotics and automation:
Supplying gripper arms with compressed air or electrical signals.
Multi-media rotary feedthroughs for flexible robot arms.

4. Medical technology:
transmission of fluids or signals in rotating medical devices (e.g. CT scanners).

5. Aerospace:
transmission of fluids in control systems for airplanes and satellites.
High-precision slip rings for radar systems.

Maintenance and fault prevention:

• Regular inspection of seals for wear by checking for leaks.
• Clean media supply to avoid contamination.
• Selecting the right rotating union for the specific application.

Rotating unions are essential components for the transmission of liquids, gases and electrical signals between stationary and rotating components. Depending on the application, there are different types, from simple fluid feedthroughs to hybrid systems for highly complex machines.

Below is an overview of the most important points to consider when purchasing rotating unions:

When purchasing rotating unions, there are numerous factors to consider to ensure optimal performance and lifetime of the union while minimizing operating costs.

• Before rotating unions can be purchased, the specific requirements must be analyzed in detail.
• Which media should be fed through at which pressures?
• Liquids: Water, oil, coolant or hydraulic fluids.
• Gases: Compressed air, vacuum or steam.
• Additionally electricity and signals: slip rings for data or power transmission.
• Pressure range: Required pressure resistance, e.g. 10-100 bar for hydraulic systems.
• Rotational speed and speed:
• Rotating unions must be designed for the planned rotational speed (rpm).
• High speed applications require special bearings and seals.
• Number of channels:
• Single channel for simple applications.
• Multi-channel for machines that use several media simultaneously (e.g. hydraulics & compressed air).
• Which sealing system is recommended for the application?
• Sliding seals: High tightness, for precise applications.
• Labyrinth seals: For high speeds, but not 100% tight.
• Rubber seals: Inexpensive, but have a limited service life.
• What temperature range is the rotating union intended for? This is important for high-temperature applications (e.g. steam, hot oils).
• Sealing materials can be NBR, FKM or PTFE, depending on the medium and temperature requirements.
• The following standards, regulations and quality assurance certificates must be observed for rotating unions:
• DIN EN 13480 - Pressure piping, - FDA approval - For the food and pharmaceutical industries, ISO 9001 - Quality assurance systems and ATEX certification - For potentially explosive environments.
• The protection classes and environmental resistance should also be taken into account:
• IP protection classes e.g. IP65 against dust & water. Corrosion protection for aggressive environments e.g. stainless steel for offshore applications. Vibration resistance for machines with strong shocks.
• Acquisition costs vs. service life - Cheaper models can cause higher maintenance costs.

A professional purchase of rotating unions requires a detailed analysis of the technical requirements, standards, delivery conditions and cost factors. The right choice increases the efficiency of the machines, reduces maintenance costs and prevents unplanned downtime.

Rotating unions can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Rotating unions from all over the world can be found on Exportpages.