280 Cupla
High-Pressure up to 700 Bar
The Nitto Kohki 280 Cupla is a high-pressure quick-release coupling in steel with NBR seals, rated for operating pressures up to 700 bar. The range includes plugs (280-xP) and sockets (280-xS) in nominal sizes 2, 3, 4, 6, and 8. Unlike the 350 Cupla (FKM seal), the 280 Cupla uses NBR seals, making it particularly suitable for mineral oil hydraulic media and water-containing hydraulic fluids.
| Type | Role | Nominal size | Material | Seal |
|---|---|---|---|---|
| 280-2P / 280-2S | Plug / Socket | 2 | Steel | NBR |
| 280-3P / 280-3S | Plug / Socket | 3 | Steel | NBR |
| 280-4P / 280-4S | Plug / Socket | 4 | Steel | NBR |
| 280-6P / 280-6S | Plug / Socket | 6 | Steel | NBR |
| 280-8P / 280-8S | Plug / Socket | 8 | Steel | NBR |
Typical applications: High-pressure hydraulic connections in machine tools and presses, hydraulic power unit connections with mineral oils (HLP) and water-mixed fluids (HFA, HFB), quick-change systems on heavy and construction machinery, and high-pressure test systems and mobile hydraulics up to 700 bar.
Technical data from the manufacturer catalogue
| Series | 280 CUPLA |
|---|---|
| Body material | Special steel (Bright chromate conversion coating : silver color) |
| Seal material | Nitrile rubber (NBR) |
| Max working pressure | 1/4 inch and 3/8 inch: 31.5 MPa {321 kgf/cm2, 315 bar, 4570 PSI}; 1/2 inch, 3/4 inch and 1 inch: 27.5 MPa {281 kgf/cm2, 275 bar, 3990 PSI} |
| Working temperature | Nitrile rubber (NBR): -20 °C to +80 °C |
| Valve structure | Two-way shut-off |
| Applicable fluids | Hydraulic oil |
| Vacuum service | 1.3 Pa {1x10-2 mmHg}: socket only not applicable, plug only not applicable, operational when connected. |
| Size range | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch |
| Catalogue page | C01en-b, 103 |
Operating principle
- Conforms to international standard ISO 7241-1A.
- Hydraulic CUPLA with the working pressure up to 27.5 to 31.5 MPa {281 to 321 kgf/cm2}.
- Structure keeps pressure loss extremely low, particularly ideal for hydraulic applications requiring high flow rates.
- Both socket and plug have built-in automatic shut-off valves to prevent fluid spill out when disconnected.
- Special steel body material is adopted for its excellent strength and additional quenching treatment is done to withstand hydro pressure impacts.
- Copes with higher pressure lines in hydraulic equipment.
- Low pressure loss is ideal for hydraulic equipment.
- Fluid flow can be bi-directional when socket and plug are connected.
All models of the series
P - Female thread
| Model | Coupling part | Application | Steel (g) | L | øD | C | T | øH(WAF) |
|---|---|---|---|---|---|---|---|---|
| 280-2P | Plug | R 1/4 | 35 | 31.5 | 20.5 | 15 | Rc 1/4 | Hex.19 |
| 280-3P | Plug | R 3/8 | 59 | 35 | 25 | 18.5 | Rc 3/8 | Hex.23 |
| 280-4P | Plug | R 1/2 | 115 | 44 | 32 | 24.5 | Rc 1/2 | Hex.29 |
| 280-6P | Plug | R 3/4 | 178 | 52.5 | 35 | 28 | Rc 3/4 | Hex.32 |
| 280-8P | Plug | R1 | 331 | 63.5 | 44 | 35 | Rc 1 | 41 |
S - Female thread
| Model | Coupling part | Application | Steel (g) | L | øD | T | øH(WAF) |
|---|---|---|---|---|---|---|---|
| 280-2S | Socket | R 1/4 | 110 | (46) | (27) | Rc 1/4 | 19 |
| 280-3S | Socket | R 3/8 | 185 | (53) | (33) | Rc 3/8 | 23 |
| 280-4S | Socket | R 1/2 | 335 | 66.5 | (39) | Rc 1/2 | 29 |
| 280-6S | Socket | R 3/4 | 571 | (81) | (48) | Rc 3/4 | 35 |
| 280-8S | Socket | R1 | 871 | 98 | (55) | Rc 1 | 41 |
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; A = hose barb length; C = sleeve dimension; T = thread or barb size; B = bore
Series comparison
| Series | Max working pressure | Size range | Valve structure | Applicable fluids |
|---|---|---|---|---|
| 210 CUPLA | 206 bar | 1/4 inch to 1 inch | Two-way shut-off | Hydraulic oil |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 450B CUPLA | 441 bar | 3/8 inch | Two-way shut-off | Hydraulic oil |
| 700R CUPLA | 686 bar | Thread 3/8 inch, 1/2 inch | Two-way shut-off | Hydraulic oil |
Choose 280 CUPLA when the hydraulic circuit works above the 20.6 to 21.0 MPa {210 to 214 kgf/cm2} rating of HSP CUPLA, HYPER HSP CUPLA, 210 CUPLA, HSU CUPLA and S210 CUPLA but stays within 27.5 to 31.5 MPa {281 to 321 kgf/cm2}. All of these series shut off on both sides, so the step up changes the pressure class and not the valve behaviour. For higher pressures there are 350 CUPLA at 34.5 MPa {352 kgf/cm2}, 450B CUPLA at 44.1 MPa {450 kgf/cm2} and 700R CUPLA at 68.6 MPa {700 kgf/cm2}; where the mating half is built to ISO 7241-1A, 280 CUPLA conforms to that standard.
Body and seal materials
| Body material |
|---|
| Special steel (Bright chromate conversion coating : silver color) |
| Seal material | Mark | Working temperature | Remarks |
|---|---|---|---|
| Nitrile rubber | NBR | -20 °C to +80 °C | Standard material |
Further catalogue data
| Note | Value |
|---|---|
| Working pressure by size | 1/4 inch and 3/8 inch: 31.5 MPa, 321 kgf/cm2, 315 bar, 4570 PSI. 1/2 inch, 3/4 inch and 1 inch: 27.5 MPa, 281 kgf/cm2, 275 bar, 3990 PSI. |
| Flow direction | Fluid flow can be bi-directional when socket and plug are connected. |
| Maximum tightening torque | 1/4 inch: 28 {286} Nm {kgf . cm}. 3/8 inch: 40 {408}. 1/2 inch: 80 {816}. 3/4 inch: 100 {1020}. 1 inch: 180 {1836}. |
| Minimum cross-sectional area (mm2) | 280-2SP: 11.4. 280-3SP: 42.8. 280-4SP: 79.1. 280-6SP: 146.5. 280-8SP: 235.6. |
| Admixture of air on connection (mL) | 280-2SP: 0.37. 280-3SP: 1.02. 280-4SP: 2.63. 280-6SP: 8.83. 280-8SP: 16.04. May vary depending upon the usage conditions. |
| WAF | WAF stands for width across flats. |
| Flow rate | The pages give flow rate - pressure loss characteristic curves only, no tabulated flow values. Test conditions: fluid hydraulic oil, fluid viscosity 32x10-6 m2/s, density 0.87x103 kg/m3; the test temperature figures are not legible in the extracted text. Curves are plotted for 280-2SP, 280-3SP, 280-4SP, 280-6SP and 280-8SP from 1 to about 300 L/min against 0.01 {0.1} to 1.0 {10} MPa {kgf/cm2}. |
Interchangeability and size groups
Socket and plug of different sizes cannot be connected. Can be connected with products whose mating part dimensions are in compliance with ISO7241-1A. There is no interchangeability between 280 CUPLA and HSP CUPLA, 210 CUPLA or 450B CUPLA.
Safety and application notes
- Before use, please be sure to read "Safety Guide" described at the end of this book and "Instruction Sheet" that comes with the products.
- There is no interchangeability between 280 CUPLA and HSP CUPLA, 210 CUPLA or 450B CUPLA. Do not connect each other even if some sizes are approximate.
- Socket and plug of different sizes cannot be connected.
- Do not exceed the maximum tightening torque given for each thread size.
All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 103. The complete catalogue is available for download on this page.
