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G™ Rotary Unions

Product catalog summary

Overview of G™ Rotary Unions

The G™ Rotary Unions by Kadant Johnson are precision-engineered components designed for high-speed fluid transfer applications including coolant, water, oil, and air. They are extensively used in machine tool industries such as CNC machining, grinding, drilling, milling, presses, and rotary index tables. These unions ensure effective cooling and lubrication with smooth, vibration-free operation through precision ball bearings, optimized seals, and rotor concentricity control.

1. Key Features

Precision ball bearings lubricated for life, ensuring maintenance-free operation.
Hardened stainless steel rotors for durability.
Optimized seal balance ratios to minimize friction and wear.
Leak-free operation enabled by laser-etched hydrodynamic grooves on seal faces.
Body materials include anodized aluminum and brass for corrosion resistance.
Special seal designs allow dry running in select models.
Labyrinth seals and drain holes protect bearings from contamination and fluid ingress.
Low vibration and heat generation support precise machining processes.
Some models compatible with proximity sensing for drawbar position detection.

2. Specifications Summary

The rotary unions cover a broad range of operating parameters depending on the series:

Pressure: Up to 5,800 PSI (GB Series), with most models rated between 1,000 and 2,175 PSI.
Temperature: Typically up to 195°F, with some models rated up to 250°F.
Rotational Speed: Ranges from 1,500 RPM (GB Series) up to 42,000 RPM (GHS/GHSA Series).

Each series is optimized for specific pressure-speed-temperature combinations to maximize joint life and performance.

3. Model-Specific Details and Applications

GA Series: General-purpose air and hydraulic unions, up to 1,500 PSI and 6,000 RPM. Bodies in anodized aluminum or brass; carbon graphite or bronze seal faces for hydraulic oil above 1,000 PSI.
GAI Series: Compact internal-mounted unions for installation inside shafts; up to 1,000 PSI and 3,500 RPM.
GFR/GFRA Series: Dry running coolant unions with silicon carbide seal faces, labyrinth seals, and drain holes; up to 1,160 PSI and 10,000 RPM.
GFL/GFLA Series: Similar to GFR but supporting speeds up to 15,000 RPM and reduced coolant misting for improved air quality.
GFS/GFSA Series: High-speed dry running unions with angular contact bearings to eliminate vibration; up to 20,000 RPM.
GFP/GFPA Series: High-pressure coolant unions with stainless steel springs outside flow path; up to 2,175 PSI and 15,000 RPM.
GB Series: High-pressure water and hydraulic unions rated up to 5,800 PSI but limited to 1,500 RPM.
Bracket Mounted Models: Support speeds up to 24,000 RPM at 1,160 PSI.
GHP/GHPA and GHS/GHSA Series: Ultra-high speed unions supporting up to 42,000 RPM with pressures around 1,160 to 2,030 PSI.

4. Technical Data and Dimensions

Detailed dimensional tables specify thread types, body dimensions, and weights for each model, provided in both metric and imperial units. Tolerances are precisely defined (e.g., +0.012" to +0.016" for GAI series). PV (Pressure-Speed) diagrams illustrate recommended operating envelopes to achieve an estimated joint life of 10,000 hours, emphasizing the importance of adhering to pressure-speed limits to avoid premature failure.

5. Recommendations and Usage Guidelines

Consult Kadant Johnson for custom requirements and specific application details.
Refer to catalog pages for precise application parameters and compatibility.
Higher speeds and pressures may be available upon consultation but require careful evaluation.
Avoid simultaneous operation at maximum pressure, temperature, and speed to prevent premature wear or failure.
Quick select charts indicate recommended, acceptable, and not recommended operating conditions for ease of selection.

6. Installation and Maintenance

Use flexible hoses (minimum 12 inches) of SAE 100R1 type AT single-braid to prevent side loading and allow free movement.
Follow OEM filtration recommendations; no additional filtration beyond coolant system requirements is necessary.
Installation instructions are available online or through Kadant Johnson sales offices.
Handle components carefully due to precise manufacturing tolerances.

7. Lubrication and Seal Technology

Seal faces are lubricated by the fluid media passing through the union.
Auto-Off™ seal devices enable dry running without damage, extending seal life.
Bearings are lubricated for life and require no additional maintenance.

8. Warranty and Support

All G rotary unions undergo testing before shipment and include a 12-month warranty against manufacturing defects. Kadant Johnson offers global sales and service support in over 150 countries.

9. Other Rotary Union Types

RX Series: Balanced seal with carbon-to-tungsten carbide faces, rated up to 500°F, 150 PSI, and 3,000 RPM; suitable for water, thermal oil, and air.
ELS Series: Carbon-graphite bearings, rated up to 650°F, 300 PSI, and 200 RPM; designed for steam and thermal oil.
Over-the-Shaft (OTS): For cooling driven roll journals, rated up to 200°F and 150 PSI.
SX Series: Steam and thermal oil unions with self-aligning bearings, rated up to 650°F, 300 PSI, and 550 RPM.

10. Custom Rotary Unions

Kadant Johnson offers custom-designed rotary unions in both housing-less and housed versions. Options include laser-etched hydrodynamic grooves to enhance seal life. Engineering support is available to tailor unions to specific application requirements.

Summary

Kadant Johnson's G series rotary unions provide a comprehensive range of high-precision, durable solutions for fluid transfer in rotating machinery. Advanced seal and bearing technologies enable high-speed operation, dry running capability, and extended service life. Detailed specifications, performance data, and installation guidelines facilitate optimal selection, integration, and maintenance in demanding industrial applications.

Catalog excerpts

For coolant, water, oil, and air service KADANT AN ACCENT ON INNOVATION Precision rotary unions for more effective cooling and lubrication. High speed rotating unions for transferring fluids and air

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Contents G™ Rotary Union Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 GA General Purpose Air and Hydraulic Rotary Unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 GAI Internal Mounted Rotary Unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 GFR/GFRA Coolant Rotary Unions for Dry Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 GFL/GFLA Coolant...

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Overview The G rotary union is a high performance, high precision rotary union for coolant, water, air, and hydraulic oil applications. The G rotary unions are generally applied to the machine tool industry for: u Transfer lines u Rotary index tables Based on decades of mechanical seal design and application expertise, the G rotary union line is built to perform under the most demanding conditions. A thorough understanding of seal load optimization, seal wear characteristics, and application knowledge means the G rotary union can provide years of reliable service for coolant, water, air, and...

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Consult factory for additional thread type Features and Benefits u Precision ball bearings lubricated for life u Body available in anodized aluminum or brass u Hardened stainless steel rotor u Stationary seal face available in carbon graphite, bronze u Optimized seal balance ratio for minimal friction seal face for hydraulic oil above 1,000 psi

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Features and Benefits u Compact design mounted inside shaft u Available with non-contacting seal ring with u Hardened stainless steel rotor hydrodynamic gi-°°ves u Optimized seal balance ratio for minimal friction u Anodized aluminum body

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*C and X in mm for metric threads Rotary Union Type GFR-GFRA PV Diagram Features and Benefits u Special seal design permits dry running u Labyrinth seal and drain holes protect bearings u Optimized seal balance ratio u Silicon carbide seal faces resist wear and thermal shock u Precision ball bearings eliminate vibration u Anodized aluminum body u Full flow area, minimal pressure drop u Stainless steel springs located outside the flow u Stainless steel rotor resists corrosion u No leakage during tool change

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Features and Benefits u Special seal design permits dry running u Optimized seal balance ratio for minimal friction u Precision angular contact bearings widely spaced to eliminate wobble and vibration u Labyrinth seal and drain holes protect bearings u Anodized aluminum body u Reduced coolant misting for improved air quality u Low heat generation in bearings and mechanical seal u No leakage during tool change commutation u Low vibration for precise machining u Also available for rotation with compressed air u Supplied with bearings run-in upon request u Closing ring suitable for proximity sensing...

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*C and X in mm for metric threads Rotary Union Type GFS-GFSA PV Diagram Features and Benefits u Special seal design permits dry running u Optimized seal balance ratio for minimal friction u High precision angular contact bearings eliminate wobble and vibration u Labyrinth seal and drain holes protect bearings u Anodized aluminum body u High speed, dry run applications u Reduced coolant misting for improved air quality u Low heat generation in bearings and mechanical seal u No leakage during tool change commutation u Low vibration for precise machining u Also available for rotation with compressed...

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Features and Benefits u Labyrinth seal and drain holes protect bearings u Optimized seal balance ratio u Silicon carbide seal faces resist wear and thermal shock u Angular ball bearing design resists side loading u Low vibration for precise machining u Anodized aluminum body u Full flow area, minimal pressure drop u Multiple stainless steel springs located outside the flow u Stainless steel rotor resists corrosion u Closing ring suitable for proximity sensing drawbar position

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Features and Benefits u Stainless steel rotor u Labyrinth seal between bearing and mechanical seals for longer lifetime and safety u Rigid bearing installation for safety u Optimized seal balance for minimal friction u Stainless steel and aluminum body u All materials in contact with medium are non-corrosive u Stainless steel springs lo

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Features and Benefits u Two channel rotary union u High speed for specific machine tool applications u Dry running capable (consult factory) u Aluminum body u Stainless steel rotor u Flanged connection for stable operation and long life u Drain connection between passages for separation of media u Also available for rotation with compressed air

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Rotary Union Type GHP-GHPA PV Diagram Features and Benefits u Special seal design permits dry running u Labyrinth seal and drain holes protect bearings u Optimized seal balance ratio u High precision angular contact bearings for high speeds u Anodized aluminum body u Full flow area, minimal pressure drop u Long drawbar stroke for maximum flexibility u Low heat generation in bearings and mechanical seal u No leakage during tool change commutation u Large drain holes to evacuate coolant from the rotary union u Supplied with bearings run-in upon request u Stainless steel springs located outside...

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Features and Benefits u Special seal design permits dry running u Labyrinth seal and drain holes protect bearings u Optimized seal balance ratio u High precision angular contact bearings for high speeds u Anodized aluminum body u Full flow area, minimal pressure drop u Long drawbar stroke for maximum flexibility u Seal to protect bearings for air pressure in rotor area u Low heat generation in bearings and mechanical seal u No leakage during tool change commutation u Large drain holes to evacuate coolant from the rotary union u Supplied with bearings run-in upon request

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