Low Pressure up to 19 bar
Nitto Kohki
The Nitto Kohki low-pressure Cupla series cover operating pressures up to 19 bar (1.9 MPa) and are designed for compressed air, nitrogen and other non-aggressive gases as well as water. From the miniature Micro Cupla through the best-selling HI Cupla (1.5 MPa) to the large-bore Super Cupla, the range offers a matching connector for every nominal size and flow requirement - in brass, steel and stainless steel 1.4301/1.4404.
All low-pressure series use the proven one-touch sleeve mechanism for tool-free connection and disconnection in under one second. The automatic socket-side shut-off prevents pressure loss on disconnection, while the ball-latch locking withstands full working pressure. ISO 6150-B versions ensure interchangeability within existing compressed-air networks.
Nitto Kohki Low Pressure - Cupla series up to 19 bar
| Criterion | Nitto Kohki | Parker | Stäubli | Rectus |
|---|---|---|---|---|
| Standard air series | HI Cupla | Rectus-compatible | RBE / RPL | Series 25/26 |
| Max. working pressure (air) | up to 2.0 MPa (Super/HI 200) | approx. 1.5 MPa | approx. 1.5 MPa | approx. 1.5 MPa |
| Nominal bore range | NB 4-20 mm | NB 5-19 mm | NB 5-18 mm | NB 5-19 mm |
| Miniature body size | Yes (Micro/Small Cupla) | Limited | Limited | Mini series |
| One-touch operation | Yes, all series | Yes | Yes | Yes |
| Body materials | Brass/steel/SUS 304/316 | Brass/steel/SUS | Brass/SUS | Brass/steel |
| ISO 6150-B | Yes | Yes | Yes | Yes |
| Series | Application | Pressure / bore | Key feature |
|---|---|---|---|
| Micro Cupla | small devices, instrumentation, lab air | up to 1.5 MPa, NB 4-6 | smallest body, brass/SUS |
| HI Cupla | general compressed air, tools | up to 1.5 MPa, NB 6-15 | standard series, most widely used |
| HI Cupla 200 | compressed air at elevated pressure | up to 2.0 MPa, NB 6-15 | 2.0 MPa variant of the HI series |
| HI Cupla ACE | low-spill air connection | up to 1.5 MPa | valved both ends |
| Super Cupla | high-flow air, large consumers | up to 2.0 MPa, NB to 20 | maximum bore |
| Lever Lock Cupla | large bores, safety-critical | up to 1.5 MPa | lever lock against accidental release |
Typical applications: compressed-air supply in manufacturing and assembly (EN ISO 4414), pneumatic hand tools and assembly lines, workshop and tyre service, laboratory and test air, nitrogen purging, and water/coolant lines in machinery and plant engineering.
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 |
|---|---|---|---|---|---|---|
| LEVER LOCK CUPLA | 18 bar | Metal body: 3/4 inch to 4 inch. Plastic body: 3/4 inch, 1 inch, 1 1/2 inch, 2 inch, 3 inch. | Straight through | Water, Hydraulic oil, Air, Powder, Steam | Aluminum alloy (AL), Copper alloy (BR), Stainless steel (SUS), Polypropylene (PP) | 77 |
| FULL BLOW CUPLA | 15 bar | Thread and hose barb 1/4 inch, 3/8 inch, 1/2 inch. SN type for urethane hose: for dia. 6.5 mm x dia. 10 mm, dia. 8 mm x dia. 12 mm, dia. 8.5 mm x dia. 12.5 mm and dia. 11 mm x dia. 16 mm polyurethane hose. | One-way shut-off | Air | Aluminum alloy | 49 |
| HI CUPLA | 15 bar | Thread and hose barb 1/8 inch to 1 inch, 1/4 inch to 1 inch hose | One-way shut-off | Air, Water | Steel (Chrome plated), Brass, Stainless steel (SUS304) | 39 |
| HI CUPLA 200 | 15 bar | Thread and hose barb 1/4 inch, 3/8 inch, 1/2 inch. Tube barb (Tube fitter): Polyurethane tube outer dia. 6 +/-0.1, 8 +/-0.15, 10 +/-0.15; Polyamide tube outer dia. 6 +0.05/-0.08, 8 +0.05/-0.1, 10 +0.05/-0.1; Fluorine contained resin tube outer dia. 6 +/-0.07, 8 +/-0.07, 10 +/-0.07. | One-way shut-off | Air | Steel (Chrome plated) | 43 |
| HI CUPLA ACE | 15 bar | Thread and hose barb 1/4 inch, 3/8 inch; PN, SN, PNG and SNG types for ø5 mm x ø8 mm, ø6 mm x ø9 mm, ø6.5 mm x ø10 mm, ø8 mm x ø12 mm and ø8.5 mm x ø12.5 mm polyurethane hose | One-way shut-off | Air, Water | Engineering plastics (PBT, POM) | 61 |
| LINE CUPLA 200 | 15 bar | - | One-way shut-off | Air | Body: Aluminum alloy, CUPLA: Steel (chrome plated) | 57 |
| COMPACT CUPLA | 10 bar | Thread 1/8 inch; tube barb for ø4 x ø6 and ø6 x ø8 tube | Two-way shut-off | Air, Water | Brass, Stainless steel (SUS304) | 31 |
| CUBE CUPLA | 10 bar | 4 mm and 6 mm ID tube, 1/8 inch | Two-way shut-off, one-way shut-off or straight through, depending on the combination of valved and valveless socket and plug. | Air, Water | Polyacetal resin (POM) | 33 |
| MICRO CUPLA | 10 bar | Thread 1/8 inch, M5x0.8. Tube barb tube ID o3, o4. Tube barb (Tube fitter): polyurethane tube outside dia. o4 +/-0.1, o6 +/-0.1; polyamide tube outside dia. o4 +0.05/-0.08, o6 +0.05/-0.08; fluorine contained resin tube outside dia. o4 +/-0.05, o6 +/-0.07 | One-way shut-off | Air, Water (Tube Fitter type is unsuitable for water.) | CUPLA : Brass (Plated), CUPLA : Stainless steel (SUS304), Tube Fitter Part : Brass (Plated), Tube Fitter Part : Plastic, MICRO LINE CUPLA branch body : aluminum alloy | 23 |
| SMALL CUPLA | 10 bar | Thread 1/8 inch, 1/4 inch; Hose barb polyamide hose o4xo6, o4.5xo6, urethane hose o4xo6; Tube barb (Tube fitter) polyurethane tube OD o6 +/-0.1, o8 +/-0.15, polyamide tube OD o6 +0.05/-0.08, o8 +0.05/-0.1, fluorine contained resin tube OD o6 +/-0.07, o8 +/-0.07 | One-way shut-off | Air, Water (Tube Fitter type is unsuitable for water.) | CUPLA : Brass (Chrome plated), Tube Fitter Part : Brass (Nickel plated) , Plastic | 27 |
| SUPER CUPLA | 10 bar | Thread: 1/8 inch, 1/4 inch. Hose barb: 1/4 inch, urethane hose ø5 x ø8, ø6.5 x ø10. Tube barb (Tube fitter): outside dia. ø6 and ø8 | One-way shut-off | Air | CUPLA : Steel (Chrome plated), CUPLA : Aluminum alloy, Tube Fitter Part : Brass (Nickel plated), Tube Fitter Part : Plastic | 37 |
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.
