fittings and tube for the interconnection of pneumatic components and systems
Post on 22-Dec-2015
226 Views
Preview:
TRANSCRIPT
Fittings and Tube
For the interconnection of pneumatic components and systems
Contents
Thread sizes Tube sizes and materials Fitting types Industry specific fittings General purpose fittings Function fittings Standards Sealing the thread Taper and parallel Pressures / temperatures
Pneufit Push-on fittings External nut compression Internal nut compression BSP and Hose fittings FleetFit (vehicle fittings)
WeldFit (welding industry ) Plasfit (brewing industry)
Tube and Hose
Presentations
Click the section or presentation to go to it
Introduction
Introduction
Fittings connect the components of a pneumatic system with flexible tubing, hose and rigid pipe
A variety of fittings ranges are produced to fulfil the needs of general and specific industries
The variables include: methods of connection thread sizes tube sizes angles of connection number of connections materials of construction applications industry standards
Thread sizes
For the majority of pneumatic applications fittings will be required in the ranges:
R 1/8 , R 1/4 , R 3/8 , R 1/2 , R 3/4
M 5, G 1/8 , G 1/4 , G 3/8 , G 1/2 , G 3/4 , G 1
NPTF 1/8 , 1/4 , 3/8 , 1/2
Tube sizes
Tube sizes are identified by their o/d (outside diameter)
The metric range covers 4, 5, 6, 8, 10, 12, 14, 16, 22, 28 mm o/d
The inch range covers 1/8 , 5/32, 3/16, 1/4, 5/16, 3/8, 1/2, 5/8, 3/4 o/d
Tube and hose materials
Plastics Polyamide ( Nylon ) Nylon, food grade Polyurethane Terylene braided PVC Metal braided rubber Weld tube
Copper Annealed Half hard standard duty Half hard heavy duty
Steel Double wall brazed
Types of Pneumatic Fittings
Push-In Fittings, very quick joint with the tube
Push-On Fittings, neat, quick joint using a finger tight nut
Compression Fittings, firm joint, for plastic or metal tube:
internal nut version external nut version
Industry specific fittings
Plasfit, hygienic, food grade plastic push in fittings designed for use in drinks dispense and brewing industries
FleetFit, brass push-in fittings with tube support, for vehicle air braking systems and auxiliary systems
WeldFit, nickel plated brass push-in fittings with tube support, for use with WeldTube to protect against damage from weld spatter.
8 m m8 m m
General purpose fittings
BSP and Hose taper and parallel fittings
Nickel plated brass construction
Adaptors Connectors Reducers Expanders Bulkheads Tees Elbows Unions Hose connectors Banjos
Function fittings
Pneumatic sensor Senses the falling
exhaust pressure in an actuator and sends a signal when it has stopped
Blocking Activated by removing a
pneumatic pilot signal to block flow one way
Pressure reducing Placed in the line to one
end of a cylinder to reduce pressure
2
1
Thread standards (Europe)
Fittings Taper male threads
comply with ISO 7 (BS 21) and are designated by R 1/8 , R 1/4 , R 3/8 , R 1/2 etc.
Parallel male and female threads comply with ISO 228 (BS 2779) and are designated G
1/8 , G 1/4 , G 3/8 , G 1/2 etc.
Parallel metric threads are to ISO 261 (BS3643) designated M5x1, M10x1, M12x1.5, etc.
Ports The ports in components
such as cylinders and valves are parallel and comply to ISO 228 (BS2779) these are designated G 1/8 , G 1/4 , G 3/8 , etc.
Parallel metric threads are to ISO 261 (BS3643) designated M5x1, M10x1, M12x1.5, etc.
Thread standards (USA)
Fittings Dryseal threads are taper
male threads NPTF “National (American) Standard Pipe Taper Fuel and Oil”
Sizes show TPI (threads per inch). The most popular range for industrial pneumatics are 1/8 -27, 1/4 -18, 3/8 -18, 1/2-14, 3/4 -14
Ports The ports in components
such as cylinders and valves are NPTF. This provides a male taper to female taper joint.
NPSF and NPSI parallel female threads also allow connection with male taper NPTF fittings
Sealing the thread
Parallel threaded fittings seal on a washer between the fitting and the face of the component’s port. The surround to the port is usually spot face machined
Taper threaded fittings rely on a lightly wedged fit and use sealant between the threads of the fitting and port
Taper to parallel
Taper fittings are made smaller in diameter as there is no bearing surface required for a washer
Taper fittings do not require the port to be spot faced so are suitable for ports in unmachined components and ports at an angle to their surface
By manufacturing to selected tolerances taper fittings are successfully used with parallel ports
This combination is very popular in many sectors of the pneumatics industry
Fittings must not be over tightened, particularly for ports in thin wall cast material as there is a risk of cracking the casting
Working pressure ranges
The safe working pressure for the majority of pneumatic systems is 10 bar maximum with some components up to 16 bar maximum
Most fittings will be safe at pressures in excess of these but obtain advice
Plastic tubing is limited by wall thicknes and operating temperature
Metal tubing has a higher rating
Pressure Max from Vacuum Pneufit 18 bar * FleetFit 10 bar WeldFit 18 bar * Plasfit 10
bar
Limited by plastic tube Push-on 9 to 11 bar Compression 15 to 28 bar
* If tubing allows andnot including regulating banjos which are 10 barTubing details
Working temperature ranges
Temperatures are generally limited by the plastic and rubber parts of a fitting and the tube material
For extreme temperatures use compression fittings and metal tube. Also choose taper threads
Where parallel threaded fittings are supplied with plastic washers the temperature is limited to- 40OC to 70OC
Push- in Range Pneufit -200C to
700C Plasfit 00C to
700C Fleetfit - 400C to 1000C Weldfit - 300C to 700C
Push- on 24 Series 0OC to 70OC
Compression fittings with metal tube at 10 bar
- 40 to +100OC BSP and Hose
limited by tube or hose
End
Pressure rating
O/D mm 4 5 6 8 10 12 14 16 22 28
Polyamide (PA) 28 31 25 19 24 18 15 18 15 15
Polyurethane (PU) 10 11 10 9 9 9
Pressure values are for a temperature range -40 OC to +20 OC
Higher temperatures OC
Pressure adjustment factor
30 40 50 60 80
0.83 0.72 0.64 0.57 0.47
bar maximum
Plastic tube
For compressed air above 16 bar consult our technical service
Pressure rating
O/D mm 4 5 6 8 10 12 16 22 28
128 138 112 81 64 81 59 53 41
Pressure values are for a temperature range -40 OC to +50 OC
Copper Annealed
Copper Half Hard 193 208 218 157 150 122 89 81 62
bar maximum
Copper and steel tube
Steel 300 250 195 160
OCAnnealed
100
Half Hard
150 175 2000.97 0.82 0.63 0.43
0.95 0.88 0.54 0.29
Pressure adjustment factors
For compressed air above 16 bar consult our technical service
Click the arrow
top related