1. Straight Push-In Fittings
Standard linear connectors for general pneumatic applications.
Q1: What is a straight push-in fitting used for? A straight fitting connects tubing to equipment or another tube in a direct, linear configuration.
Q2: Which tube materials are compatible? They work with PU (Polyurethane), PA (Nylon), and PE (Polyethylene) tubing.
Q3: Are straight fittings reusable? Yes. Simply press the release ring (collar) to unlock and remove the tubing.
Q4: Do these fittings support vacuum applications? Yes, high-quality pneumatic straight connectors support both positive pressure (up to 10 bar) and vacuum (down to -0.95 bar).
Q5: What thread types are available? Depending on the model, available threads include Metric (M5–M27), BSPT (R), BSPP (G), and NPT.
Q6: Do I need thread seal tape for installation? Only for metal threads that do not come with pre-applied sealant. Tapered threads with pre-coated sealant do not require tape.
Q7: What are the operating pressure and temperature ranges?
- Pressure: Typically -0.95 bar (vacuum) to 10 bar (150 PSI).
- Temperature: -20°C to +60°C, depending on the tube and fitting material.
Q8: Are they leak-proof? Yes, provided the tubing is cut squarely and inserted fully past the sealing O-ring.
Q9: Are standard fittings compatible with DOT air brake systems? No. Standard pneumatic fittings are for industrial use. DOT-approved air brake systems require specialized DOT-certified fittings.
Q10: Can straight fittings handle lubricated air? Yes, they are compatible with lubricated air systems.
Q11: Do straight fittings rotate? Standard straight fittings do not rotate. However, some specific models feature a rotary body.
Q12: Can I use them outdoors or for food-grade applications?
- Outdoors: Brass or nickel-plated versions are recommended for corrosion resistance.
- Food-Grade: Stainless steel versions must be used for food contact applications.
Q13: What tube sizes are available? Common metric sizes include 4, 6, 8, 10, 12, 14, and 16 mm.
Q14: How is the tube retained inside the fitting? A stainless-steel collet (lock claw) with high-grip teeth holds the tube securely.
Q15: Can I connect two tubes without threads? Yes, by using a Straight Union (PU/APU) connector.
2. Elbow Fittings
90° angled connectors for changing direction.
Q1: Why use elbow fittings? They allow tubing to turn 90° without bending, kinking, or stressing the tube, which is essential in tight spaces.
Q2: What types of elbow fittings are available? Common types include Male Elbow, Female Elbow, Long Elbow, and Universal Swivel Elbow.
Q3: Are elbow fittings directional? Yes. The threaded side connects to the port/device, while the push-in side connects to the tubing.
Q4: Can elbow fittings rotate after installation? Swivel models (Universal Elbows) can rotate 360° after installation for flexible positioning. Fixed elbows cannot.
Q5: What is a Universal Elbow? It is a swivel-type elbow designed to allow the tubing outlet to be positioned in any direction after the thread is tightened.
Q6: Are elbow fittings compatible with air cylinders? Yes, especially Meter-In/Meter-Out versions combined with flow control valves.
Q7: Do elbow fittings reduce airflow? They may cause a slight reduction due to the directional change and turbulence compared to straight fittings.
Q8: Are they suitable for robotics? Yes, they are widely used in robotics to route cabling/tubing neatly and reduce stress on moving parts.
Q9: How do I orient a swivel elbow? Hand-tighten the fitting first, then rotate the body to the desired direction before final securing.
Q10: Do long elbows offer advantages? Yes, extended/long elbows provide better clearance when installing multiple fittings side-by-side on a manifold.
3. Tee & Y Fittings
Branching connectors for splitting or combining airflow.
Q1: What is the difference between a Tee and a Y fitting?
- Tee Fitting: Branches airflow at a 90° angle (T-shape).
- Y Fitting: Splits airflow at an angle (Y-shape), offering smoother flow with less turbulence.
Q2: Can these fittings split airflow equally? Yes, assuming the downstream tubing lengths and restrictions are identical.
Q3: What types are available?
- Tee: Male Tee, Female Tee, Union Tee, Reducing Tee.
- Y: Union Y, Reducing Y, Male Y.
Q4: Do reducing Tees/Ys exist? Yes, Reducing Tees and Ys allow you to connect tubes of different diameters (e.g., 8mm input to two 6mm outputs).
Q5: Are Y fittings directional? No, they can be used to split one line into two, or combine two lines into one.
Q6: Can these fittings handle vibration? Yes, provided the tubing is secured properly. Y-fittings are often preferred in dynamic applications as they are more compact.
Q7: Are they suitable for manifold connections? Yes, Tee fittings are ideal for creating parallel connections in manifold-style layouts.
4. Bulkhead Fittings
Panel-mount connectors for passing tubing through walls.
Q1: What is a bulkhead pneumatic fitting used for? It allows tubing or piping to pass through a panel, wall, or machine enclosure while maintaining a sealed, vibration-resistant connection.
Q2: When should I use a bulkhead union? Use it when you need to transition airflow through a metal plate, control panel, or housing case.
Q3: What is the difference between Bulkhead Straight and Bulkhead Elbow?
- Bulkhead Straight: Passes through the panel in a straight line.
- Bulkhead Elbow: Provides a 90° turn immediately on one side of the panel.
Q4: Do bulkhead fittings come with mounting hardware? Yes, most premium models include the necessary lock nut and washer/O-ring for installation.
Q5: Are they leak-proof under vibration? Yes, the lock nut design anchors the fitting securely to the panel, preventing movement and leaks.
Q6: Can they be used in truck and trailer systems? Yes, they are common in air suspension systems, auxiliary pneumatics, and cab control panels.
5. Valves & Flow Control
Manual and automatic regulation of airflow.
Q1: What is a pneumatic hand valve used for? It allows an operator to manually shut off or release airflow in a circuit for safety or maintenance.
Q2: What is the difference between a Check Valve and a Flow Control Valve?
- Check Valve: Allows air to flow in only one direction and blocks reverse flow.
- Flow Control Valve: Regulates the speed/volume of airflow (usually adjustable).
Q3: When should I use Meter-In vs. Meter-Out flow control?
- Meter-Out: Controls the exhaust air; typically used to control the speed of pneumatic cylinders (extension/retraction) for smoother movement.
- Meter-In: Controls the supply air; used for single-acting cylinders or specific applications.
Q4: How do I adjust a flow control valve? Turn the needle knob or screw on top of the fitting to increase or decrease airflow.
Q5: Can check valves be installed in any direction? No. They must be oriented according to the flow arrow printed on the body.
Q6: Are pneumatic valves reusable? Yes, most metal-bodied valves are reusable if the seals remain intact.
6. Reducer & Specialty Fittings
Adaptors for different sizes and specific configurations.
Q1: What is a reducer fitting used for? To connect tubing or threads of different sizes (e.g., connecting a 10mm tube to a 6mm tube).
Q2: Reducing Union vs. Reducing Tee: Which to choose?
- Reducing Union: For a straight, inline size change.
- Reducing Tee: When adding a smaller branch line to a main line.
Q3: Can reducer fittings connect mixed thread standards? Yes, specialty adaptors can convert between Metric, BSP, and NPT threads.
Q4: What are “Specialty Fittings”? These include multi-port connectors (like Cross or Manifold fittings) designed for complex automation, robotics, and packaging machinery.
Q5: Do reducing Y fittings split airflow equally? Yes, provided the resistance downstream is balanced.
7. Inch (Imperial) Push-In Fittings
Connectors sized for North American standards.
Q1: What are inch push-in fittings? These are connectors designed specifically for imperial tubing sizes (measured in fractions of an inch).
Q2: Are inch fittings compatible with metric tubing? No. The Outer Diameter (OD) must match exactly. For example, 1/4″ (6.35mm) tubing will not seal correctly in a 6mm fitting.
Q3: What are the common inch tube sizes? Common sizes include 5/32″, 1/4″, 5/16″, 3/8″, and 1/2″.
Q4: What thread standard do inch fittings usually use? NPT (National Pipe Taper) is the most common thread type for inch fittings.
Q5: Are they compatible with standard push-to-connect brands? Yes, they are generally interchangeable with major brands using the same sizing standards.
Q6: Can I use them for garage air compressor lines? Yes, inch fittings are widely used in workshops and garage setups in North America.
