Model 70 Diving FRU

Model 70 Fluid Rotary Union

The Model 70 is a multi-pass fluid rotary union that has served as the standard FRU to the diving industry for over 30 years. It is available as a stand alone FRU or can be combined with electric slip ring and fiber optic rotary unions. Typically configured with up to 13 passes, inter-port mixing is prevented through the use of double seals and an intermediate vent between passes. It has also proven itself in non diving applications such as centrifuge, indexing tables, and floating oil production swivels where product quality is paramount.

The Model 70 is available in several standard port configurations as illustrated below. The Model 70 is available with two standard application specific seal options. In its standard configuration, it is rated for 1000 psi [68 bar] at 10 rpm continuous service and up to 30 rpm intermittent service.


  • Configurable with up to 13 ports as standard
  • 1/4, 1/2, 5/8 and 1 inch SAE straight thread o-ring ports standard
  • Corrosion resistant materials suitable for hot sea water and other harsh chemicals
  • Rated to 1000 psi [68 bar] at 10 rpm continuous service
  • Maximum speed 30 rpm intermittent
  • Polymer bearings eliminate the need for periodic service
  • Optional rolling element bearing design available
  • Available with hollow bore for ESR / FORJ pigtails


  • Continuous 360º rotation
  • Proven reliability
  • Provides long maintenance free service
  • Configurable
Ambient Temperature
-40°C to +60°C
-40°C to +100°C
0°C to +60°C
Pressure1 1000 psi
Rotational Speed1
10 rpm continuous
30 rpm intermitent
(Dependent on configuration)
Consult product specific installation drawing. Operating torque varies based on number of passes, shaft diameter, pressure, speed, medium and seal type
Shock / Vibration MIL-STD-167 (ships)
Weight Dependent on configuration
Marine, open deck
Leakage Std. Seal 50 std. mL / min N2 gas per seal rotating @ 1000 psi max
Typically less than 10 std. mL / min N2 gas per seal rotating @ 1000 psi
Low Leak Seal 2 std. mL / min N2 gas per seal rotating @ 1000 psi max
Typically less than 0.05 std. mL / min N2 gas per seal rotating @ 1000 psi
Nominal Port Size
1/4 inch
1/2 inch
5/8 inch
1 inch
SAE straight thread O-ring thread size
7/16-20 UNF
3/4-16 UNF
7/8-14 UNF (passage size suitable for 3/4" nominal, 1-1/16-12 UN adapter)
1-5/16-12 UN
1 Operational life is dependent on pressure, temperature, rotational speed duty cycle and size of assembly. Maximum values do not apply concurrently. Please consult the factory for actual value.
2 Break-in torque may be higher.
Flexible conduit should be used to couple to the rotating component. The torque arm must be loose coupled.

Contact Us

Technical Support

Telephone:  +1-902-468-2263

Typical Applications

  • Marine - diving umbilical winches, seismic survey winches,  hydraulic control winches
  • Scientific - centrifuges
  • Military - radar turrets
  • Industrial - machining centers, rotary index tables, heavy equipment turrets, cable reels, packaging machines, palletizing machines, labeling machines, remote sensing