SEC Manufactures three main types of Extruders
HOT Feed Extruders
COLD Feed Extruders
PIN & BARREL Type Extruders
The general Specifications of a typical SEC Extruder Are The Following
Screw – Alloy steel of EN-24 with flights cut on thread milling machine duly centrally bored for water circulation. Flights heat treated hardened nitrided & ground with hardness approx. 65 to 70 RC. The screw is machined in Right Hand profile on a special thread milling machine from alloy steel EN 41 B and heat treated hardened nitrided to approx. 70 RC. The working length of screw is 5 X Diameter (L/D Ratio 5) in case of Hot Feed Extruders and in case of Cold Feed Extruders, the ratio varies from 12 to 16 and caries reverse threads at rear end to prevent the material flow in backward direction.
Barrel Cylinder – Alloy steel tested pipe fabricated from steel pipe with Horizontal passages for water circulation.
Liner – EN 41 B alloy steel with inner dia drilled, Bored Ground and heat treated hardened (nitrided) for hardness app. 65 to 70 RC.
Bed Plate – The Bed Plate is of Steel welded fabrication construction composed of Steel beams, channels and plates. Machined pads are provided to mount main motor, Gear Reducer, Extruder Barrel and Cylinder Support, Leveling pads included at bottom side, in addition to foundation holes, for filed installation The standard arrangement for drive mounting is motor mounted outward for ease of maintenance / disassembly.
Gear and Gear Reducer – The inter connecting gears are grease lubricated and made of EN 36 alloy steel, teeth hob cut & case carburized hardened for better wear life. This is of Indian Standard make Greaves / Flender / Elecon / Shanthi Gears and is of horizontally mounted, parallel shaft, multi – reduction, case hardened and ground helical gearing supported on heavy duty antifriction bearings. The case is steel fabricated stress relived and fully machined horizontally split design unit and carries Thrust Bearing inbuilt housing at output end.
Forward Cylinder Support – A rugged, fabrication steel support, mounted in front of Extruder, to accommodate the weight of the forward cylinder and Head.
The output shaft is internally bored to permit mounting of screw cooling arrangement.
The gearing and bearings including Thrust Bearing is splash lubricated with bottom race of Thrust Bearing remaining in oil bath always.
The Main Motor to Gear Reducer in connected through Lovejoy type flexible coupling. A coupling guard included.
Forward Cylinder Barrel – Manufactured from ultrasonically & chemically tested Alloy steel & jacketed / drilled & connected in alternate circuits for circulation of temperature control water media with inlet & outlet connections. The lnner bore is heat treated (Nitrided) hardened to 60/70 RC for a depth of 0.5 – 0.6 mm.
The forward Cylinder in full length has Two Temperature Control Zones.
The Barrel is designed for max. operating pressure of 5,700 psi (400 bar) & normal working pressure is appx. 5000 psi (350 bar) & is based on Die Opening.
The forward and rear sections of the barrel Cylinder are fitted with flanges to accept Die in front and to bolt to feed Hopper section at rear.
Feed Hopper – Manufactured of steel welded construction with double wall jacketed construction with connections for cooling / heating media (water) circulation, the feed Hopper is cut machined to mount feed Roll and also has on undercut to facilitate Rubber strip continuous feed into Extruder barrel. An integral extension to the rear of the Feed opening isolates the feed zone from the gearbox Thrust Bearing to prevent any material working past the bronze gland at the rear of the screw into the Bearing area. A cage mode of smooth rotating thin bars is mounted over feed opening to guide rubber strip to the feed section.
The feed opening width is 150 mm
Feed Roll – The Feed Roll is centrally hollow and provision is made for water-cooling. An adjustable scrapper is mounted underneath Feed Roll to scrap the Roll thus ensuring roll surface to be clean of rubber. The Feed Roll housing is bolted to the Feed Hopper Extruder and can be easily dismounted when required. The feed roll is positively driven from screw by inter connecting gears and carries a tangential speed friction of minor value of 1:1. 12 for pushing the rubber in.
Main Motors – A fixed or variable speed (AC/DC drives) main motor can be provided as per the customer requirement. The motors will be Indian standard make – siemens Abb/BB/Kirloskar etc. with class F insulation and continuous rating.
Controls – In case DC drives the controls will be 3 phase, 6 pulse, 440 V, Digital Thyristor converter Panel with Tacho included. Ambient 45 C, Class 1 duty (100% continuous), IP 30 Protection Panel. The controls are suitable for unidirectional operation with speed control range 1:20 of base speed with constant torque Speed regulation shall be + 0.5% of base speed at base speed by means of tacho feedback. Necessary switch gear along with drive module such as incoming MCCB, Line reactor, Feeder for DC Motor field and blower included.