Rotary Unions GP Series

GP Series 3-Passage Rotary Unions & Joints

GP Series 3-Passage Rotary Unions & Joints
Maximum Pressure See Other Pressure Options
Maximum Speed See Other Speed Options
Connection Type See Other Connection Options
Suitable Media* See Other Media Options
*Suitable Water/Glycol or Coolant media must have rust inhibitors present. Oil/Hydraulic media must be petroleum-based. Please consult with DSTI for approval.

The 3-passage, GP Series rotary unions feature specialized sealing technology suitable for vacuum and bidirectional pressures and three independent flow passages capable of transferring different media types simultaneously.

The carbon steel (black oxide) construction is suitable for air/gas, coolant, and hydraulic service. Stainless steel models are available to prevent corrosion for use with applications requiring water or corrosive media transfer (see GPS Series).

GP 3-passage models with NPT thread connections consist of a unique shaft configuration for easier installation, allowing the choice of mounting the shaft connections using the threaded passages or O-ring face seal glands for flush mounting the union to an interface. GP 3-passage models with BSPP thread connections are not available with O-ring face seal glands.

Need to combine fluid with electrical power, signal and/or data transfer? No problem. The GP Series rotary unions are designed to integrate directly with our standard electrical slip rings. See options.


Part # Connection Passage Size Diameter Length Through Bore Min. Torque* Part Downloads Information
GP-130 [GPM-130]1/8"-27 NPT [G1/8"-28 BSPP]0.156" [3.962 mm]2.687" [68.25 mm]4.147" [105.334 mm]None1.5 ft-lbs [2.03 Nm] Buy Now
GP-131 [GPM-131]1/8"-27 NPT [G1/8"-28 BSPP]0.156" [3.962 mm]2.937" [74.6 mm]4.186" [106.325 mm]0.500" [12.7 mm]2.6 ft-lbs [3.53 Nm] Buy Now
GP-230 [GPM-230]1/4"-18 NPT [G1/4"-19 BSPP]0.250" [6.35 mm]3.187" [80.95 mm]5.290" [134.366 mm]None5.3 ft-lbs [7.19 Nm] Buy Now
GP-231 [GPM-231]1/4"-18 NPT [G1/4"-19 BSPP]0.250" [6.35 mm]3.750" [95.25 mm]5.601" [142.266 mm]0.750" [19.05 mm]7.6 ft-lbs [10.3 Nm] Buy Now
GP-330 [GPM-330]3/8"-18 NPT [G3/8"-19 BSPP]0.375" [9.525 mm]3.875" [98.425 mm]6.030" [153.162 mm]None7.6 ft-lbs [10.3 Nm] Buy Now
GP-331 [GPM-331]3/8"-18 NPT [G3/8"-19 BSPP]0.375" [9.525 mm]4.187" [106.35 mm]6.342" [161.087 mm]0.750" [19.05 mm]9.5 ft-lbs [12.88 Nm] Buy Now
GP-430 [GPM-430]1/2"-14 NPT [G1/2"-14 BSPP]0.500" [12.7 mm]4.250" [107.95 mm]7.061" [179.35 mm]None9.5 ft-lbs [12.88 Nm] Buy Now
GP-431 [GPM-431]1/2"-14 NPT [G1/2"-14 BSPP]0.500" [12.7 mm]4.937" [125.4 mm]7.406" [188.113 mm]0.750" [19.05 mm]16.2 ft-lbs [21.96 Nm] Buy Now
GP-530 [GPM-530]3/4"-14 NPT [G3/4"-14 BSPP]0.750" [19.05 mm]5.250" [133.35 mm]8.280" [210.312 mm]None16.2 ft-lbs [21.96 Nm] Buy Now
GP-630 [GPM-630]1"-11.5 NPT [G1"-11 BSPP]1.000" [25.4 mm]6.937" [176.2 mm]10.570" [268.479 mm]None24.7 ft-lbs [33.49 Nm] Buy Now

*Minimum torque required to rotate based on zero pressure with Oil/Hydraulic media (or Air/Gas media for SPS Series). Required torque to rotate may be greater when using other media types or dry running. For specific torque requirements, please contact DSTI to discuss your application.

Technical Specifications

Maximum Pressure 7,500 PSI [515 BAR]
Maximum Speed 500 RPM
Maximum Vacuum 30 HG
Temperature Range 0° F to 220° F [-18° C to 105° C]
Suitable Media* Air/Gas, Coolant, Oil/Hydraulic, Water/Glycol
Connection Type NPT, BSPP
GP Series Rotary Unions - Housing Material
Housing: Material (Plating/Coating) Carbon Steel (Black Oxide)
GP Series Rotary Unions - Shaft Material
Shaft: Material (Plating/Coating) Carbon Steel (Black Oxide)

*Suitable Water/Glycol or Coolant media must have rust inhibitors present. Oil/Hydraulic media must be petroleum-based. Please consult with DSTI for approval. All values listed under Technical Specifications are dependent on a combination of all application parameters. Please note operational life is dependent upon both rotational speed and duty cycle. Contact DSTI if your application requires operating close to the maximum rotational speed with a continuous duty cycle. Applications with temperatures above 220° F (105° C) require alternative seal materials. The use of Water media with temperatures above 212° F (100° C) require alternative seal materials. Please consult with DSTI regarding your specific application requirements.

Available Options

Available Custom Modifications for GP Series Rotary Unions

Custom Modifications

Easier and less expensive than you may think. We can modify our standard products to fit your project requirements.

Learn More
Electrical Slip Rings for GP Series Rotary Unions

Electrical Slip Ring Integration

Get the complete package. We offer a wide range of electrical slip rings designed to directly integrate with our GP Series rotary unions.

View Options


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