Quick connect coupling 350 Cupla 350-4S, steel - Nitto Kohki 431204100

In hydraulic circuits with strong pressure peaks, the coupling decides how much air enters the oil on connection. The Nitto Kohki 350 Cupla works up to 34.5 MPa and lets only 0.1 mL to 2.0 mL of air into the line when coupled, depending on size.

• Working pressure up to 34.5 MPa (345 bar, 5000 PSI), designed for hydraulic lines with large pressure fluctuations
• Shut-off valves in both socket and plug close on disconnection, so the oil stays in the line
• Air admixture on connection of only 0.1 mL on the 350-2SP up to 2.0 mL on the 350-16SP, measured with hydraulic oil at 40 °C
• Locking mechanism against accidental disconnection keeps the joint tight under vibration and impact
• The seal does not protrude into the fluid path when coupled, which extends seal life
• Nickel-plated special steel body, quenched to take pressure impulses

Technical data from the manufacturer catalogue

Dimensions

Dimensions in millimetres. Values in brackets apply in the connected condition.

Legend: L = overall length; H = width across flats or outside dimension; D = socket outside diameter; T = thread or barb size

Models in this series 350 CUPLA

Every model of the series as printed in the manufacturer catalogue. The row of the article offered here is highlighted.

Operating principle

• Body is made of special steel for durability. The body material is quenched to cope especially with impulses.
• Separation prevention mechanism is easily locked by turning the sleeve after connection.
• Both socket and plug have built-in automatic shut-off valves to prevent fluid spill out when disconnected.
• Push-to-connect operation.
• Their airless valve shut-off design greatly reduces air admixture.
• For hydraulic lines with large pressure fluctuations.

Series comparison

Choose 350 CUPLA when the hydraulic line needs more than the 20.6 to 21.0 MPa that HSP CUPLA, HYPER HSP CUPLA, 210 CUPLA, HSU CUPLA and S210 CUPLA offer, and more than the 27.5 to 31.5 MPa of 280 CUPLA, but does not require the 44.1 MPa of 450B CUPLA or the 68.6 MPa of 700R CUPLA. All of these siblings are two-way shut-off; 350 CUPLA adds spill reduction, and its airless valve design keeps air admixture low, which is the argument on lines with large pressure fluctuations. For hydraulic oil at 34.5 MPa {352 kgf/cm2} with an FKM seal it is the direct choice within this group.

Body and seal materials

Applications

• Hydraulic power units and hydraulic lines up to 34.5 MPa
• Circuits with pronounced pressure fluctuations and impulses
• Lines exposed to vibration or impact where the lock prevents disconnection
• Connections with high flow rate, the minimum cross-sectional area runs from 34.2 mm² on the 350-2SP to 907.9 mm² on the 350-16SP
• Release of residual pressure through the optional PAD-2 purge adapter rated for 35.0 MPa

Compatibility

Sockets and plugs of different sizes cannot be connected, the exceptions being 350-2SP with 350-3SP and 350-10SP with 350-12SP. Once coupled, fluid flows in either direction, and the range is not suitable for vacuum in either the connected or the disconnected state.

Standards and compliance

End connections are female Rc 1/4 to Rc 2 threads, G threads on request, the sealing materials are nitrile rubber (NBR, marked SG) for -20 °C to +80 °C and fluoro rubber (FKM, marked X-100) for -20 °C to +180 °C.

Safety and application notes

• Precautions for use: Do not connect / disconnect CUPLA when pressure is applied or remaining.
• Not suitable for vacuum application in either connected or disconnected condition.
• Before use, please be sure to read "Safety Guide" described at the end of this book and "Instruction Sheet" that comes with the products.

All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 105. The complete catalogue is available for download on this page.