High pressure up to 700 bar
Nitto Kohki
The Nitto Kohki high-pressure Cupla series are rated for operating pressures up to 700 bar (70 MPa) and intended for hydraulic oil, water and test media in high-pressure technology. The pressure-class-named series 210, 280, 350, 450B and 700R make selection unambiguous - the number equals the maximum working pressure in bar. They are complemented by the HSP and HSU series with screw-to-connect locking for maximum safety.
Hardened steel bodies and stainless versions (S210, SUS 316) withstand pressure peaks and continuous load in accordance with the Pressure Equipment Directive 2014/68/EU (PED). Pressure-relieved valves allow disconnection even under trapped residual pressure - essential for safe work on presses, clamping systems and test rigs.
Nitto Kohki High Pressure - Cupla series up to 700 bar
| Criterion | Nitto Kohki | Parker | Stäubli | Rectus |
|---|---|---|---|---|
| Max. working pressure | up to 700 bar (70 MPa) | approx. 400 bar | approx. 250-500 bar | approx. 350 bar |
| Pressure-class grading | 210/280/350/450B/700R | limited | RPL/RPG series | limited |
| Screw-to-connect locking | Yes (HSP/HSU) | Partial | Yes | Rare |
| Pressure-relieved disconnect | Yes | Yes | Yes | Partial |
| Body material | hard. steel/SUS 316 | steel | stainless | steel |
| PED 2014/68/EU | Yes | Yes | Yes | Yes |
| Series | Application | Pressure class | Key feature |
|---|---|---|---|
| HSP Cupla | high-pressure hydraulics | up to ~30 MPa | standard high-pressure series, steel |
| 210 Cupla | hydraulics, clamping | up to 210 bar | pressure-relieved |
| 280 Cupla | presses, tool making | up to 280 bar | hardened steel |
| 350 Cupla | high-pressure hydraulics | up to 350 bar | fatigue-resistant |
| 450B Cupla | test rigs, power units | up to 450 bar | high-pressure locking |
| 700R Cupla | water-jet, pressure testing | up to 700 bar | highest pressure class |
Typical applications: high-pressure hydraulics and clamping systems, press and tool making, hydraulic pressure testing and test rigs, water-jet cutting and high-pressure cleaning, mobile hydraulics, and power units to PED 2014/68/EU.
Series in this category compared
Maximum working pressure is the first selection criterion. It decides the series, not the size: a low pressure coupling does not become high pressure capable by choosing a larger bore.
| Series | Max working pressure | Sizes | Shut-off type | Fluids | Body material | Catalogue page |
|---|---|---|---|---|---|---|
| 700R CUPLA | 686 bar | Thread 3/8 inch, 1/2 inch | Two-way shut-off | Hydraulic oil | Special steel (Nickel plated) | 112 |
| 450B CUPLA | 441 bar | 3/8 inch | Two-way shut-off | Hydraulic oil | Special steel (Nickel plated) | 111 |
| PURGE ADAPTER | 350 bar | R 1/4 (PAD-2), R 3/8 x Rc 3/8, R 1/2 x Rc 1/2, R 3/4 x Rc 3/4, R 1 x Rc 1 | - | Hydraulic oil | Steel (nickel plated) | 168 |
| 350 CUPLA | 345 bar | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch, 1 1/4 inch, 1 1/2 inch | Two-way shut-off (Spill Reduction) | Hydraulic oil | Special steel (Nickel plated) | 105 |
| 280 CUPLA | 315 bar | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off | Hydraulic oil | Special steel (Bright chromate conversion coating : silver color) | 103 |
| HSU CUPLA | 210 bar | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off | Water, Hydraulic oil, Gas | Stainless steel (SUS304) | 99 |
| 210 CUPLA | 206 bar | 1/4 inch to 1 inch | Two-way shut-off | Hydraulic oil | Special steel (Nickel plated) | 97 |
| HSP CUPLA | 206 bar | 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch, 1 1/4 inch, 1 1/2 inch, 2 inch | Two-way shut-off | Hydraulic oil | Special steel (Nickel plated) | 91 |
| HYPER HSP CUPLA | 206 bar | 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off | Hydraulic oil | Special steel (Nickel plated) | 95 |
| S210 CUPLA | 206 bar | 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off | Water, Hydraulic oil, Gas | Stainless steel (SUS304) | 101 |
The four shut-off types
The shut-off type decides what happens on disconnection. It is the second criterion and depends on whether the line is under pressure when it is parted and how much fluid may escape.
Choosing a coupling in five steps
- Fix the fluid and the operating temperature, which gives the seal material.
- Determine the maximum working pressure, which gives the pressure class and the series.
- Choose the shut-off type: one-way, two-way, valveless or flat face.
- Fix the end connection and size: hose barb, male thread, female thread or tube fitter.
- Choose the body material for the fluid and the environment, then order plug and socket as a pair.
This page is based on the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, 190 pages. The complete catalogue is available for download on this page.
