In-Line Purge Adapter
Quick couplings
The Nitto Kohki In-Line Purge Adapter is a steel purge adapter with NBR seal that is installed directly in line in a compressed-air circuit, allowing targeted flushing of defined sections. The range covers four types (PAD-3FM, PAD-4FM, PAD-6FM, PAD-8FM) in nominal sizes 3, 4, 6, and 8. The adapters allow removal of moisture, particles, or residues from specific line sections without full disassembly.
| Type | Nominal size | Material | Seal |
|---|---|---|---|
| PAD-3FMSTEELNBR | 3 | Steel | NBR |
| PAD-4FMSTEELNBR | 4 | Steel | NBR |
| PAD-6FMSTEELNBR | 6 | Steel | NBR |
| PAD-8FMSTEELNBR | 8 | Steel | NBR |
Typical applications: Cleaning and flushing of compressed-air line sections during plant maintenance, removal of condensate and particles from pneumatic systems, preparation of lines for leak testing, and purge operations in food, medical, and cleanroom technology.
Technical data from the manufacturer catalogue
| Series | In-Line PURGE ADAPTER |
|---|---|
| Body material | Steel (Nickel plated) |
| Seal material | Nitrile rubber (NBR), standard material |
| Max working pressure | 35.0 MPa {357 kgf/cm2, 350 bar, 5080 PSI} |
| Working temperature | Nitrile rubber (NBR): -5 °C to +80 °C |
| Applicable fluids | Hydraulic oil |
| Vacuum service | Not suitable for vacuum application. |
| Size range | 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. |
| Catalogue page | C01en-b, 168 |
Operating principle
- Can be attached to hydraulic lines to purge residual pressure effectively.
- Can be operated with a screwdriver if the button is stiff. Insert an ordinary flat head screwdriver into the groove in the valve holder and press the button by leverage.
- Residual pressure is purged through a drain outlet port by pushing the residual pressure purge button.
- PAD-2 comes with a tube fitting included; PAD-FM types are supplied without tube fittings.
- FLOW METER: graduated scale shows the coolant flow rate numerically, thus reducing operator variation in setting cooling conditions.
- FLOW METER: although small, it has a built-in flow rate adjustment valve, allowing the molding conditions of each machine to be set freely.
- FLOW METER: molding conditions are reproducible and lead time can be shortened.
- FLOW METER: installation and replacement is easy since the screw part of the T2 side rotates freely to the left and right.
All models of the series
FM - Female thread both ends
| Model | Coupling part | Application | Brass (g) | L | øD | øH1(WAF) | øT1 | øT2 |
|---|---|---|---|---|---|---|---|---|
| FM-03-B | flow meter | Rc 3/8 both ends | 190 | (89) | (33) | Hex.23 | Rc 3/8 | Rc 3/8 |
PAD-2 - Female thread with tube fitting
| Model | Coupling part | Application | Steel (g) | øD | øH (WAF) | øL1 | øP1 | øP2 | øT1 | øT2 |
|---|---|---|---|---|---|---|---|---|---|---|
| PAD-2 | purge adapter | R 1/4 | 235 | 39.5 | Hex.36 | (62) | (48) | 14 | R 1/4 | 8 |
PAD-3FM/4FM - For thread connection
| Model | Coupling part | Application | Steel (g) | øD | øB | øH (WAF) | øL1 | øL2 | øL3 | øP1 | øP2 | øT1 | øT2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PAD-3FM | purge adapter | R 3/8 x Rc 3/8 | 320 | 10 | (11) | 29 | 72.5 | (39) | 21.5 | (51) | (33.5) | R 3/8 | Rc 3/8 |
| PAD-4FM | purge adapter | R 1/2 x Rc 1/2 | 307 | 12.5 | (11) | 29 | 72.5 | (39) | 21.5 | (51) | (33.5) | R 1/2 | Rc 1/2 |
PAD-6FM/8FM - For thread connection
| Model | Coupling part | Application | Steel (g) | øD | øB | øH (WAF) | øL1 | øL2 | øP1 | øP2 | øT1 | øT2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PAD-6FM | purge adapter | R 3/4 x Rc 3/4 | 665 | 16.5 | (15.5) | Hex.46 | 86 | 21.5 | (63.5) | (38) | R 3/4 | Rc 3/4 |
| PAD-8FM | purge adapter | R1 x Rc 1 | 620 | 21.5 | (15.5) | Hex.46 | 86 | 21.5 | (63.5) | (38) | R1 | Rc 1 |
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 |
Use the In-Line PURGE ADAPTER when residual pressure has to be released from a hydraulic line at up to 35.0 MPa {357 kgf/cm2} before the coupling is separated, since it is fitted into the line itself and does not replace the coupling. The purging peer series in this category, PURGE HI CUPLA at 1.5 MPa {15 kgf/cm2} and PURGE LINE CUPLA at 1.0 MPa {10 kgf/cm2}, are couplings for the low pressure range and do not reach this pressure level. Where the line only has to be connected and shut off, the one-way shut-off peers such as HI CUPLA BL, NUT CUPLA or LOCK CUPLA 200, or the two-way shut-off COMPACT ZEROSPILL CUPLA, are the appropriate choice.
Body and seal materials
| Body material |
|---|
| Steel (Nickel plated) |
| Seal material | Mark | Working temperature | Remarks |
|---|---|---|---|
| Nitrile rubber | NBR | -5 °C to +80 °C | Standard material |
Further catalogue data
| Note | Value |
|---|---|
| Drain outlet port, PAD-2 | For 8 mm OD tube |
| Drain outlet port, PAD-3FM to PAD-8FM | Rc 1/8 (Max. Tightening Torque: 5 Nm) |
| Working pressure, all models | 35.0 MPa / 357 kgf/cm2 / 350 bar / 5080 PSI |
| Maximum tightening torque | R 1/4: 28 {286} Nm {kgf . cm}; R 3/8 x Rc 3/8: 40 {408}; R 1/2 x Rc 1/2: 80 {816}; R 3/4 x Rc 3/4: 150 {1530}; R1 x Rc 1: 250 {2550} |
| Minimum cross-sectional area, mm2 | PAD-2: -; PAD-3FM: 78.5 (ø10); PAD-4FM: 122 (ø12.5); PAD-6FM: 213 (ø16.5); PAD-8FM: 363 (ø21.5) |
| Residual pressure purge speed comparison | Test conditions: fluid hydraulic oil, fluid viscosity 32x10-6 m2/s, pressure 35 MPa, cubic capacity of piping approx. 5 L. PAD-2 and PAD-FM are plotted against our current model over 0 to 5 s and 0 to 40 MPa. |
| FLOW METER FM-03-B, body material | Brass; graduated tube (scale tube) of polycarbonate |
| FLOW METER FM-03-B, size | Both ends Rc 3/8 female thread |
| FLOW METER FM-03-B, working pressure | 0.5 MPa / 5 kgf/cm2 / 5 bar / 72.5 PSI |
| FLOW METER FM-03-B, maximum flow rate | 18 L/min (5 to 18 L/min adjustable) |
| FLOW METER FM-03-B, seal material | Nitrile rubber (NBR), standard material |
| FLOW METER FM-03-B, maximum tightening torque | 11 {112} Nm {kgf . cm} |
| FLOW METER FM-03-B, flow direction | Fluid must flow in the direction of the arrows. |
| FLOW METER FM-03-B, pressure - flow characteristics | Chart only, no tabulated values. Test conditions: fluid water. Pressure loss plotted from 0.001 {0.01} to 0.1 {1} MPa {kgf/cm2} against 1 to 100 L/min, with valve opening level of the FM type shown. |
Safety and application notes
- When ordering, please indicate Model Name or part number.
- Semi standard items: as these items are not always in stock, delivery time is subject to confirmation.
- Not suitable for vacuum application.
- The operable temperature range depends on the operating conditions.
- FLOW METER: plastic part (scale tube) cannot be replaced.
- FLOW METER: fluid must flow in the direction of the arrows.
All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 168. The complete catalogue is available for download on this page.
