Fittings and Tube For the interconnection of pneumatic

Fittings and Tube For the interconnection of pneumatic components and systems

Contents Introduction Presentations l 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 l Click the section or presentation to go to it l l l l l Pneufit Push-on fittings External nut compression Internal nut compression BSP and Hose fittings Fleet. Fit (vehicle fittings) Weld. Fit (welding industry ) Plasfit (brewing industry) Tube and Hose

Introduction Fittings connect the components of a pneumatic system with flexible tubing, hose and rigid pipe l A variety of fittings ranges are produced to fulfil the needs of general and specific industries l The variables include: l l l l l methods of connection thread sizes tube sizes angles of connection number of connections materials of construction applications industry standards

Thread sizes l l 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 l l l 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 / , 5/ , 3 / , 1 / , 5 / , 3 / , 1 / , 8 32 16 4 16 8 2 5/ , 3/ o/d 8 4

Tube and hose materials l Plastics l l l l Copper l l Polyamide ( Nylon ) Nylon, food grade Polyurethane Terylene braided PVC Metal braided rubber Weld tube Annealed Half hard standard duty Half hard heavy duty Steel l Double wall brazed

Types of Pneumatic Fittings l l l 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: l l internal nut version external nut version

Industry specific fittings l l l Plasfit, hygienic, food grade plastic push in fittings designed for use in drinks dispense and brewing industries Fleet. Fit, brass push-in fittings with tube support, for vehicle air braking systems and auxiliary systems Weld. Fit, nickel plated brass push-in fittings with tube support, for use with Weld. Tube to protect against damage from weld spatter. 8 mm

General purpose fittings l l BSP and Hose taper and parallel fittings Nickel plated brass construction l l l l l Adaptors Connectors Reducers Expanders Bulkheads Tees Elbows Unions Hose connectors Banjos

Function fittings l Pneumatic sensor l l Blocking l l Senses the falling exhaust pressure in an actuator and sends a signal when it has stopped Activated by removing a pneumatic pilot signal to block flow one way Pressure reducing l Placed in the line to one end of a cylinder to reduce pressure 2 1

Thread standards (Europe) Fittings l l l 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 (BS 3643) designated M 5 x 1, M 10 x 1, M 12 x 1. 5, etc. Ports l l The ports in components such as cylinders and valves are parallel and comply to ISO 228 (BS 2779) these are designated G 1/8 , G 1/4 , G 3/8 , etc. Parallel metric threads are to ISO 261 (BS 3643) designated M 5 x 1, M 10 x 1, M 12 x 1. 5, etc.

Thread standards (USA) Fittings l l 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/ -27, 1/ -18, 3/ -18, 1/ 8 4 8 2 3 14, /4 -14 Ports l l 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 l l 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 l l 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 l l 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 l Pneufit 18 bar * l Fleet. Fit 10 bar l Weld. Fit 18 bar * l Plasfit 10 bar Limited by plastic tube l Push-on 9 to 11 bar l Compression 15 to 28 bar * If tubing allows and not including regulating banjos which are 10 bar Tubing details

Working temperature ranges l l l 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 - 40 OC to 70 OC l Push- in Range l l l Push- on l l 24 Series 0 OC to 70 OC Compression fittings with metal tube at 10 bar l l Pneufit -200 C to 700 C Plasfit 00 C to 700 C Fleetfit - 400 C to 1000 C Weldfit - 300 C to 700 C - 40 to +100 OC BSP and Hose l limited by tube or hose

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Pressure rating Plastic tube O/D mm 4 5 6 8 10 12 14 16 22 28 28 31 25 19 24 18 15 15 Polyurethane (PU) 10 11 10 9 9 bar maximum Polyamide (PA) 9 Pressure values are for a temperature range -40 OC to +20 OC For compressed air above 16 bar consult our technical service Higher temperatures OC 30 40 50 60 80 Pressure adjustment factor 0. 83 0. 72 0. 64 0. 57 0. 47

Pressure rating Copper and steel tube O/D mm 4 5 6 8 10 12 16 22 28 Copper Annealed 128 138 112 81 64 81 59 53 41 Copper Half Hard 193 208 218 157 150 122 89 81 62 bar maximum Steel 300 250 195 160 Pressure values are for a temperature range -40 OC to +50 OC For compressed air above 16 bar consult our technical service Pressure adjustment factors OC Annealed Half Hard 100 150 175 200 0. 97 0. 82 0. 63 0. 43 0. 95 0. 88 0. 54 0. 29

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