FF Cupla
Quick couplings
The Nitto Kohki FF Cupla is a flat-face quick coupling in steel with an NBR seal, available in nominal sizes 3, 4, 6 and 8 as plug (P) and socket (S). The flat-face design closes both coupling halves flush, eliminating spray when disconnecting under pressure and reducing leakage to a minimum. FF Cupla is suitable for compressed air and other gaseous media at low to medium operating pressures.
| Type | Material | Seal | Version |
|---|---|---|---|
| FF-3P / FF-3S | Steel | NBR | Size 3, plug / socket |
| FF-4P / FF-4S | Steel | NBR | Size 4, plug / socket |
| FF-6P / FF-6S | Steel | NBR | Size 6, plug / socket |
| FF-8P / FF-8S | Steel | NBR | Size 8, plug / socket |
Typical applications: Compressed air lines in production plants with frequent coupling changes, pressurised gas supply systems where spray or leakage on disconnection must be avoided, pneumatic test rigs, assembly lines, and applications with hydraulic or pneumatic media where a flat-face design is specified for environmental or safety reasons.
Technical data from the manufacturer catalogue
| Series | FLATFACE CUPLA FF |
|---|---|
| Body material | Special steel (Nickel plated) |
| Seal material | Nitrile rubber (NBR) |
| Max working pressure | 35.0 MPa {357 kgf/cm2} |
| Working temperature | Nitrile rubber (NBR): -20 to +80 deg C |
| Valve structure | Two-way shut-off (Spill Reduction) |
| Applicable fluids | Hydraulic oil |
| Vacuum service | Not suitable for vacuum application in either connected or disconnected condition. |
| Size range | 3/8 inch, 1/2 inch, 3/4 inch, 1 inch (thread) |
| Catalogue page | C01en-b, 109 |
Operating principle
- Compared with 350 CUPLA and FLATFACE CUPLA F35, the flow volume is increased 1.5 to 2 times. The increase ratio of each flow volume depends on the CUPLA product size.
- Airless valve shut-off design minimizes spillage volume on disconnection and admixture volume of air on connection.
- Suitable for hydraulic lines with drastic high pressure pulsation such as in die-casting machines.
- Separation prevention mechanism preventing accidental disconnection under vibration or impacts enhances workability and safety.
- Sizes are Rc 3/8, Rc 1/2, Rc 3/4, and Rc 1. Only the same size of socket and plug can be connected.
- Unique flat face design: concaved offset for the flat face on socket guides plug for quick and smooth centering and connection, but still easy to wipe off dirt and dusts.
- Offset concave flat face enables quick and smooth connection.
- Hexagon nut for easy mount.
All models of the series
P - Female thread
| Model | Coupling part | Application | Steel (g) | L | A | T | øH (WAF) | øoD |
|---|---|---|---|---|---|---|---|---|
| FF-3P | Plug | R 3/8 | 252 | (66) | 20.5 | Rc 3/8 | Hex.29 | 34 |
| FF-4P | Plug | R 1/2 | 409 | (74) | 22.8 | Rc 1/2 | Hex.32 | 42 |
| FF-6P | Plug | R 3/4 | 709 | (82.5) | 27 | Rc 3/4 | Hex.41 | 54 |
| FF-8P | Plug | R1 | 1314 | (96.5) | 29.5 | Rc 1 | Hex.54 | 66 |
S - Female thread
| Model | Coupling part | Application | Steel (g) | L | T | øH (WAF) | øoD |
|---|---|---|---|---|---|---|---|
| FF-3S | Socket | R 3/8 | 345 | (71) | Rc 3/8 | Hex.29 | (35.5) |
| FF-4S | Socket | R 1/2 | 608 | (84) | Rc 1/2 | Hex.32 | (44) |
| FF-6S | Socket | R 3/4 | 1053 | (95) | Rc 3/4 | Hex.41 | (54) |
| FF-8S | Socket | R1 | 1865 | (109.5) | Rc 1 | Hex.54 | (66) |
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 |
|---|---|---|---|---|
| HSP-DC CUPLA | 206 bar | 1/4 inch to 1 inch (applicable pipe size 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch) | Two-way shut-off | Hydraulic oil |
| FLATFACE CUPLA F35 | 350 bar | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off (Spill Reduction) | Hydraulic oil |
| FLATFACE CUPLA FF | 350 bar | 3/8 inch, 1/2 inch, 3/4 inch, 1 inch (thread) | Two-way shut-off (Spill Reduction) | Hydraulic oil |
| In-Line PURGE ADAPTER | 350 bar | PAD-2: R 1/4. PAD-3FM: R 3/8 x Rc 3/8. PAD-4FM: R 1/2 x Rc 1/2. PAD-6FM: R 3/4 x Rc 3/4. PAD-8FM: R 1 x Rc 1. | - | Hydraulic oil |
Choose FLATFACE CUPLA FF when the line carries hydraulic oil at a working pressure of up to 35.0 MPa {357 kgf/cm2}; the sibling series in this category are rated 1.0 to 1.5 MPa {10 to 15 kgf/cm2} and cannot be used at that pressure. Its two-way shut-off closes both socket and plug, whereas HI CUPLA BL, NUT CUPLA, LOCK CUPLA 200, HI CUPLA Two Way Type, PURGE HI CUPLA, PURGE LINE CUPLA, ROTARY LINE CUPLA, ROTARY FULL BLOW LINE CUPLA and ROTARY PLUG shut off on one side only. COMPACT ZEROSPILL CUPLA is the only sibling that also shuts off on both sides, but at 1.0 MPa {10 kgf/cm2}.
Body and seal materials
| Body material |
|---|
| Special steel (Nickel plated) |
| Seal material | Mark | Working temperature | Remarks |
|---|---|---|---|
| Nitrile rubber (NBR) | - | -20 to +80 deg C | Standard material |
Further catalogue data
| Note | Value |
|---|---|
| Pressure unit conversion | Working pressure 35.0 MPa / 357 kgf/cm2 / 350 bar / 5080 PSI |
| Maximum tightening torque, N m {kgf cm} | 3/8 inch: 40 {408}; 1/2 inch: 80 {816}; 3/4 inch: 150 {1530}; 1 inch: 250 {2550} |
| Flow direction | Fluid flow can be bi-directional when socket and plug are connected. |
| Minimum cross-sectional area (mm2) | FF-3SxFF-3P: 51; FF-4SxFF-4P: 106; FF-6SxFF-6P: 215; FF-8SxFF-8P: 332 |
| Admixture of air on connection (mL) | FF-3SxFF-3P: 0.018; FF-4SxFF-4P: 0.029; FF-6SxFF-6P: 0.033; FF-8SxFF-8P: 0.080. May vary depending upon the usage conditions. |
| Volume of spillage per disconnection (mL) | FF-3SxFF-3P: 0.009; FF-4SxFF-4P: 0.023; FF-6SxFF-6P: 0.031; FF-8SxFF-8P: 0.110. May vary depending upon the usage conditions. |
| WAF | WAF stands for width across flats. |
| Flow rate | Flow rate - pressure loss characteristics are given as a graph on page 110. Test conditions: fluid hydraulic oil, temperature 30 deg C +/- 5 deg C, fluid viscosity 32x10-6 m2/s, density 0.87x103 kg/m3. Curves are plotted for FF-3SxFF-3P, FF-4SxFF-4P, FF-6SxFF-6P and FF-8SxFF-8P over a flow rate range of 1 to 1000 L/min and a pressure loss range of 0.01 {0.1} to 1.0 {10} MPa {kgf/cm2}. |
Interchangeability and size groups
Socket and plug of different sizes cannot be connected. Only the same size of socket and plug can be connected.
Safety and application notes
- Precautions for use: Do not connect / disconnect CUPLA when pressure is applied or remaining.
- Before use, please be sure to read the Safety Guide described at the end of this book and the 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 109. The complete catalogue is available for download on this page.
