Medium Pressure up to 75 bar
Nitto Kohki
The Nitto Kohki medium-pressure series bridge the gap between compressed-air and high-pressure hydraulics, covering operating pressures up to 75 bar (7.5 MPa). The TSP and SP series are non-spill couplings with double- or single-side shut-off - ideal for nitrogen, CO₂, industrial gases, hydraulic oil and coolants where leakage and air inclusion must be avoided.
The pressure-relieved sleeve mechanism allows connection even under residual pressure, while the double-valve design of the TSP Cupla keeps both medium and system fully closed on disconnection. Steel and stainless-steel SUS 316 bodies with FKM/NBR seals are designed for demanding media and temperatures.
Nitto Kohki Medium Pressure - TSP & SP Cupla up to 75 bar
| Criterion | Nitto Kohki | Parker | Stäubli | Rectus |
|---|---|---|---|---|
| Max. working pressure | up to 7.5 MPa (75 bar) | approx. 6.3 MPa | approx. 5-6 MPa | approx. 5 MPa |
| Non-spill technology | Yes (TSP/Zero Spill) | Yes | Yes (CBI) | Partial |
| Double-side shut-off | Yes (TSP Cupla) | Yes | Yes | Limited |
| Integrated ball valve | Yes (TSP-BV) | Rare | No | No |
| Body materials | Steel/SUS 316 | Steel/brass | Stainless | Steel/brass |
| Gas / inert-gas suitability | Yes, N₂ / CO₂ | Yes | Yes | Partial |
| Series | Application | Pressure / spec | Key feature |
|---|---|---|---|
| TSP Cupla | gas, oil, coolant | up to 7 MPa | valved both ends, non-spill |
| Zero Spill Cupla | sensitive/expensive media | up to 7 MPa | minimal media loss on disconnect |
| SP Cupla Type A | hydraulics, gas lines | up to 7 MPa | single-side valve |
| TSP-BV Cupla | maintenance, transport safety | up to 7 MPa | integrated ball valve, lockable |
Typical applications: nitrogen and CO₂ supply, hydraulic test benches and clamping hydraulics, cooling and tempering circuits, industrial-gas distribution, and systems requiring non-spill disconnection and inert-gas tightness (e.g. food, beverage and laboratory applications).
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 |
|---|---|---|---|---|---|---|
| SP CUPLA Type A | 75 bar | 1/8 inch to 2 inch | Two-way shut-off | Water, Hydraulic oil, Chemicals, Air, Gas, Steam | Brass, Stainless steel (SUS304), Steel (Nickel plated) | 85 |
| TSP CUPLA | 75 bar | 1/8 inch to 2 inch (thread and hose) | Straight through | Water, Hydraulic oil, Chemicals, Air, Gas, Steam | Brass, Stainless steel (SUS304), Steel (Nickel plated), SUS316 (available as option) | 81 |
| ZEROSPILL CUPLA | 36 bar | 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch (thread) | Two-way shut-off (Spill Reduction) | Water, Hydraulic oil, Chemicals, Air, Gas | Brass, Stainless steel (SUS 304) | 89 |
| TSP CUPLA Socket with Ball Valve | 10 bar | 1/4 inch to 1 inch | One-way shut-off | Water, Hydraulic oil, Air, Gas | Brass | 83 |
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.
