Rotary Unions for Coolant Manufacturer

Rotary Unions for Coolant: A Comprehensive Guide

In the world of industrial machinery and manufacturing, ensuring the efficient operation of equipment is crucial. One often overlooked but essential component in many machining and manufacturing processes is the rotary union for coolant. These unassuming devices play a vital role in maintaining the performance, longevity, and productivity of machinery. In this blog post, we will delve deep into the world of rotary unions for coolant, exploring their functions, types, applications, and much more.

What is a Rotary Union for Coolant?

A coolant rotary union, also known as a coolant swivel or rotary coupling, is a mechanical device designed to facilitate the transfer of coolant from a stationary source to a rotating component in machinery. Its primary function is to supply coolant, typically a liquid or gas, to moving parts, preventing overheating and ensuring optimal performance during operation.

These unions are engineered to handle high pressures and rotational speeds while maintaining a leak-free seal, which is crucial for the longevity of both the union and the machinery it serves. Without a proper coolant rotary union, machinery could experience issues such as overheating, premature wear of components, and reduced efficiency.

What Are Rotary Unions for Coolant?

Definition & Basic Functionality

A rotary union is a mechanism that allows fluid to flow from a stationary supply (e.g., a coolant tank) into a rotating component (e.g., a spindle or drum). In coolant applications, its primary purpose is to:

Deliver lubrication and temperature control to cutting tools, bearings, or machinery parts.
Prevent leaks that could damage equipment, compromise safety, or increase operational costs.
Without rotary unions, systems like CNC lathes, printing presses, or wind turbines would face catastrophic failures due to overheating or friction.

Key Components of a Coolant Rotary Union

While designs vary by manufacturer and application, most rotary unions share these core elements:
Housing: The outer casing is typically made of stainless steel, aluminum, or engineered plastics.
Shaft/Rotor: The rotating part connected to the machinery.
Bearings: Support the shaft and reduce friction during rotation.
Seals: Critical for preventing leaks (e.g., mechanical seals, lip seals, or gas seals).
Ports: Inlet and outlet connections for coolant supply and return.
Mounting Flange: Attaches the union to the machine.

How Do Coolant Rotary Unions Work?

The Physics Behind Fluid Transfer

Coolant rotary unions operate on the principle of dynamic sealing. As the shaft rotates, seals maintain contact with the housing to prevent leakage while allowing fluid to pass through. Key mechanisms include:
Mechanical Seals: Use a spring-loaded rotating face and stationary seat.
Lip Seals: Employ flexible elastomers (e.g., nitrile, Viton) to create a barrier.
Magnetic Couplings: Seal-less designs using magnetic fields to transfer fluid.

Coolant Flow Dynamics

The efficiency of a rotary union depends on:
Flow Rate: Balancing supply and demand to avoid cavitation or pressure drops.
Viscosity: Thicker fluids (e.g., oil) require higher torque-resistant bearings.
Temperature Control: Coolant must absorb heat without degrading seals or lubrication.

Common Challenges

Leakage: Often caused by worn seals, misalignment, or excessive pressure.
Overheating: Inadequate coolant flow or poor thermal management.
Vibration: Results from imbalance at high RPMs.

Types of Rotary Unions for Coolant

Bearingless Unions

 

1117 series:

Deublin’s 1117 bearingless rotary union utilizes closed seal technology for long service life under harsh operating conditions. With bearingless unions, speed can range from 10,000 rpm up to 50,000 rpm. The elimination of bearings in this design reduces overall cost and allows for higher rotational speeds.

1121 series:

The bearingless 1121 rotary unions implement ppop-off®sealing technology. This unique feature allows the union to dry run even in the absence of media pressure. The short pop-off stroke limits coolant leakage when there is a tool change, making it ideal for applications where tool changes are frequent.

1124 series:

The 1124 full-flow design features balanced mechanical seals with patented auto sense® technology. This technology is a game-changer as it can sense if the media is coolant, MQL (Minimum Quantity Lubrication), or dry air and then respond by changing the seal operation accordingly. The bearingless rotating union is available with a threaded rotor only.

1139 series:

The 1139 bearingless, all-media rotary union features Deublin’s patented pop-off® seal technology. Pop-off seals remain closed when coolant is present, but allow a microscopic gap between the seals when pressure is removed. The non-rotating part of the union has a “stroke” to remain sealed when thermal expansion is caused by the spindle. This makes it suitable for applications where thermal expansion is a concern.

1154 series:

The 1154 auto sense rotary union automatically adjusts between sealing operations to accommodate different types of media. The long-stroke feature tracks drawbar movement, ensuring that the coolant supply remains consistent even when there are changes in the position of the drawbar.

1159 series:

Cool control technology in the 1159 series reduces coolant leaks when there is a tool change. An air pilot is used to keep the seals closed at the time of an axial drawbar movement. 1159 also contains autosense seal technology to adjust seals based on the media type, reducing seal wear and maintenance.

Bore-Mounted Unions

Spindles with machined counter bores require a bore-mounted rotary union. The bore-mounted union features a channel that guides leakage through a drain line to prevent the spindle from flooding.

1109 series:

Deublin is also available in a bore-mounted design. Pop-off seal technology can run without media pressure, reducing early wear of seals. Pop-off rotary unions are best in through-spindle coolant applications.

1111 series:

Deublin’s bore-mounted rotary unions are designed for long-lasting service and ease of installation. They are engineered to fit perfectly into spindles with machined counterbores, providing a reliable coolant transfer solution.

1114 series:

Through-spindle coolant rotary unions, like the 1114 bore-mounted model, deliver media directly to the source to control overheating and increase productivity. It is easy to install and can handle up to 19mm of axial drawbar movement. Designed with autosense technology, the seals adjust based on the type of media.

Rotor-Mounted Unions

Rotor-mounted unions attach directly to the machining center by the threaded rotor. The design makes for ease of installation and absorbs the thrust load on the spindle caused by coolant pressure.

1005 series:

Deublin’s bearing-supported, coolant rotary union is a single-piece design for ease of installation and replacement. Deublin offers two mounting styles, rotor, and bore, to fit nearly all machining applications.

1101 series:

Deublin’s rotary union for coolant is designed with closed seal technology to reduce seal wear by remaining closed with or without the presence of media. The bearing-supported rotary union can absorb the spindle’s thrust load, reducing early wear.

1109 series:

Deublin’s popoff® design allows unlimited dry running without media pressure to prevent early seal wear. Pop-off rotary unions are best for machining that utilizes through-spindle coolant.

1114 series:

Deublin’s auto sense® sealing technology automatically senses the type of media and responds by adjusting the seal operation. This response provides higher feed rates and reduces unnecessary downtime. The threaded rotor is available in radial and axial connections with ease of installation.

Multi-Passage Unions

A multi-passage rotating union requires balanced mechanical seals to handle high speeds and to reduce the wear of the union. Deublin’s standard line of multi-passage rotary unions can meet a variety of application needs, including work holding requiring 1 to 8 channels.

2620 series:

When transferring two types of media, Deublin’s multi-passage 2620 contains two independent passages with balanced mechanical seals. The seal design allows for maximum operation and an increased life span. The two-passage rotary union is recommended for applications such as machine tool spindles, diaphragm chucks, or clamping and unclamping.

2630 – 2650 series:

The multi-passage rotary union contains 3 to 5 independent passages for different types of media, including coolant and dry air. Balanced mechanical seals are integrated with autosense technology to withstand high speeds and pressures. The 2630 is a powerful solution for clamping, tool sensing, and spindle cooling.

2606 – 2608 series:

Best suited for data-driven rotary tables, the multi-passenger high-speed rotary union can have up to 8 media channels for various media. Closed-seal technology keeps passages independent, restricting media from mixing without leakage.

1379 – 1479 series:

Designed with four independent passages, Deublin’s 1379 and 1479 rotary unions operate with various types of media such as hydraulic oil. A vent between passages eliminates cross-contamination of two types of media. The four-passage rotary union is best for applications like clamping, unclamping, and more.

Applications of Rotary Unions for Coolant

Machining Centers

In machining centers, rotary unions for coolant are used to supply coolant to the cutting tools. This helps reduce the temperature of the cutting tool and the workpiece, which in turn improves the quality of the cut, extends the life of the cutting tool, and increases the overall productivity of the machining process. For example, in high-speed milling operations, a coolant rotary union ensures that a continuous supply of coolant reaches the cutting edges of the milling cutter, preventing overheating and reducing the risk of tool breakage.

Lathes

Lathes are another common application for coolant rotary unions. The coolant is used to cool the cutting tool and the workpiece during turning operations. A well-functioning rotary union for coolant in a lathe can improve the surface finish of the turned part, reduce the amount of heat generated during the cutting process, and increase the efficiency of the lathe operation.

Grinding Machines

Grinding machines generate a significant amount of heat during operation. Rotary unions for coolant are used to supply coolant to the grinding wheel and the workpiece. The coolant helps in dissipating the heat, preventing the workpiece from overheating and getting damaged, and also helps in flushing away the grinding debris. This results in a better-quality finish on the ground surface and extends the life of the grinding wheel.

Printing Presses

In printing presses, rotary unions for coolant are used to cool the printing cylinders. The coolant helps in maintaining the temperature of the cylinders, which is crucial for ensuring accurate printing and preventing issues such as ink smudging and uneven printing. A reliable coolant rotary union ensures a consistent supply of coolant to the cylinders, even during high-speed printing operations.

Advantages of Using Rotary Unions for Coolant

Improved Machinery Performance

By providing a continuous and efficient supply of coolant to the moving parts of machinery, rotary unions for coolant help in maintaining the optimal operating temperature of the equipment. This leads to improved performance, as components can operate at their designed efficiency levels without the risk of overheating-induced malfunctions.

Extended Equipment Lifespan

Coolant plays a vital role in reducing wear and tear on machinery components. Rotary unions ensure that the coolant reaches all the necessary parts, protecting them from excessive heat and friction. This significantly extends the lifespan of the equipment, reducing the need for frequent replacements and costly repairs.

Increased Productivity

With better-performing and longer-lasting machinery, businesses can experience increased productivity. For example, in a manufacturing plant, if the machining equipment is running smoothly with the help of effective coolant rotary unions, more parts can be produced in a given time frame, leading to higher output and potentially increased revenue.

Cost Savings

Although rotary unions for coolant are an investment, they can lead to significant cost savings in the long run. By reducing equipment downtime due to overheating and wear, and by extending the lifespan of machinery, businesses can save on maintenance, repair, and replacement costs. Additionally, improved productivity can also contribute to overall cost savings.

Maintenance and Care of Rotary Unions for Coolant

Regular Inspection

It is essential to regularly inspect the rotary union for coolant. Check for any signs of leakage, wear and tear on the seals, and damage to the housing. Leakage can indicate a problem with the seals, and if left unaddressed, can lead to coolant loss and potential damage to the machinery. Wear and tear on the seals can be caused by high pressures, speeds, or the quality of the coolant. If detected early, worn-out seals can be replaced, preventing more significant issues.

Cleaning

The rotary union should be cleaned regularly to remove any debris, dirt, or coolant residue that may have accumulated. This is especially important in applications where the coolant contains abrasive particles. Cleaning the union helps in maintaining its proper functioning and extends the life of the seals. Use appropriate cleaning agents and tools to avoid damaging the union.

Lubrication

Proper lubrication of the moving parts of the rotary union is crucial. Lubrication reduces friction, which in turn reduces wear and tear on the components. Use the recommended lubricants and follow the manufacturer’s guidelines for lubrication intervals.

Seal Replacement

Over time, the seals in the rotary union will wear out. It is important to have a schedule for seal replacement based on the manufacturer’s recommendations and the operating conditions of the machinery. When replacing the seals, use high-quality replacement parts to ensure a proper fit and reliable performance.

Case Studies

Case Study 1: Automotive Supplier Reduces Downtime by 40%

Problem: Frequent leaks in CNC spindle unions caused 12 hours/month of downtime.
Solution: Upgraded to high-speed ceramic-sealed unions.
Result: MTBF increased from 3 months to 18 months.

Case Study 2: Food Processor Achieves Hygienic Compliance

Problem: Bacteria buildup in rotary fillers led to recalls.
Solution: Installed sanitary unions with electropolished surfaces.
Result: Passed FDA audits with zero non-conformities.

Conclusion

Rotary unions for coolant are an integral part of many industrial processes. They play a crucial role in maintaining the performance, longevity, and productivity of machinery by ensuring a proper supply of coolant to moving parts. With a wide variety of types available, each designed to meet specific application requirements, it is important to choose the right rotary union for your machinery.

By understanding how they work, their applications, advantages, maintenance needs, and the factors to consider when choosing one, you can make an informed decision that will benefit your business in the long term. Whether you are in machining, manufacturing, or any other industry that relies on machinery, investing in a high-quality rotary union for coolant is a step towards more efficient and reliable operations.