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Agro Engineers
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Kota - 324007, INDIA.
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Salient Features of Agnee Extruder Gear Boxes

Gears & Pinions : Gears and pinions are of helical type manufactured from high quality alloy case hardening steel. Case hardened surface with softer core provides improved wear resistance and fatigue strength. These are subsequently flank ground to precision grade to ensure high standard of accuracy, long life and quiet running characteristics.

Case : The high quality, close-grained cast iron casing horizontally - split in 2 - pieces accommodates the bearings and the gear trains. AGNEE extruder gearboxes are designed in double reduction version with thrust bearing housing integrally cast to horizontally split case. The case design has been computer optimised on CAD work station to provide precisely calculated strengthening ribs and optimal wall thickness in critical load carrying areas. They are provided with easily accessible service ports.

Bearings : Taper roller bearings from major manufacturers are used throughout except the thrust bearing which is of self-aligning spherical roller type. These bearings have ample capacity to support combined radial and thrust loads.

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Capacity Rating Chart
Capacity Ratings chart of Agnee Extruder Gearboxes

Dimensions
Dimension Charts of Extruder Gearbox

Approved Lubricants for Extruder Gear Box

Shafting : Input shaft integral with pinion is machined from case- hardening alloy steel. Direct hardening steel is used for hollow output shaft. The cylindrical seats for bearings, wheel, seal, coupling, fan are finished by precision grinding. Fitment dimensions towards specific screw shaft requirement must be addressed during placement of order.

Shaft Seals : The shaft extensions are fitted with spring-loaded rubber seals to prevent outflow of oil.

Lubrication : Lubrication of gears and bearings is entirely self-contained by automatic ‘Splash’, which provides ample and positive flow of oil resulting minimum wear and noise. The cast tray inside the top case guides churned lubricants towards the bearings. The core hole connecting the thrust bearing housing and main oil sump ensures continuous circulation of oil flowing through the spherical roller thrust bearing at the output end. Recommended oil is of viscosity grade ISO:VG-320 with EP additives. No special care is required except occasional topping up of the oil. It is not advisable to mix two equivalent brands of lubricating oil.

Cooling : Standard gear units are cooled by normal heat dissipation through convection/radiation from externally exposed surface. All such units have provisions for fitment of cooling water coil at the bottom of oil sump. Built-in cooling coils are provided against specific options.

Direction of Rotation : The units may be operated in either direction of rotation as per requirement.

Product Certification : Being manufactured under a quality system certified to ISO : 9001:2008

Painting : Casting surfaces are painted with linear epoxy primer both internally and externally. External cast faces are finally finished with PU blue Coatings, which is resistantto dilute acids and alkalis, oils and solvents, sea water and temperatures upto 140oC. Preservation / Protection AGNEE Extruder gear units are despatched without oil. Prior to despatch they are test run with a rust preventative oil assuming adequate protection to internal parts for a period of 6 months, covering normal transport and covered storage.

Preservation / Protection : AGNEE Extruder gear units are despatched without oil. Prior to despatch they are test run with a rust preventative oil assuming adequate protection to internal parts for a period of 6 months, covering normal transport and covered storage.

NOTE :
As improvements in design are being continuously made, this specification is not to be regarded as binding and is subject to alterations without notice.

Selection Procedure

AGNEE Extruder gearbox size is to be determined against rated output torque capacity in consideration with necessary service factor. The thrust bearing size should thereafter be cross-checked against its suitability in terms of basic dynamic load rating.
1.0Selection Of Size of Reducer :
1.1Gearbox ratio = Input speed / output speed
1.2 Select the nearest nominal ratio and corresponding actual ratio from the available chart.
1.3 Determine the demand torque at output based on consumed load (*) and output rpm
Required torque (Nm)=9550 x Actual Reducer Power (Absorbed power (kW)*) X service Factor /Ooutput speed (rpm)
(* In absence of consumed load, take motor power)
1.4 Get required output torque of the gearbox by multiplying the demand torque with necessary mechanical service factor. The minimum service factor is recommended to be between 1.5 and 2.0 depending upon the operating duration and loading character.
Required output torque (Nm)=Demand torque (Nm) x service factor
1.5 From the mechanical torque rating table select a suitable size wherein the rated output torque meets or exceeds the required torque under point, 1.4 with the pre-determined ratio.

2.0 Check For Thermal Rating :

2.1 Thermal ratings are listed for following cases:
1. Gearbox without additional cooling (i.e. with natural heat dissipation through connection & radiation)
2. Gearbox fitted with cooling water coil.

2.2 Determine the thermal service factor from table.
2.3 Calculate the required thermal power capacity on the basis of absorbed power (*) and thermal service factor corresponding to specified ambient temperature and running hours.
Required thermal power (kW) = Absorbed power (kW)*/Thermal service factor.
(* In absence of consumed load, take motor power)

2.4Check the type of cooling (with or without cooling coil) by referring to thermal rating table. The required thermal power must be equal to or less then the thermal capacity of the gearbox as tabled in this catalogue.

3.0 Check for Thrust Bearing :
3.1 The screw diameter, working pressure, screw rpm and thrust bearing life expectancy are to be specified by the extruder manufacturers.

3.2 Calculate the thrust load (Fa) from the following relationship :
Fa=3.14 X Ds² X Pa / 4 X 10000
Fa=Thrust load from extruder (kN)
Ds=Extruder screw diameter (mm)
Pa=Working pressure (bar)

3.3 Calculate the thrust bearing capacity (Ca) on the following basis :
Ca=1.06 x Fa x (Lh X 60 X Ns/10) ^3/10

Where, Ca=Required bearing capacity (kN)
Fa=Thrust load from extruder (kN)
Lh=Bearing life expectancy (hrs)
Ns=Speed of extruder screw (rpm)

3.4 Check the basic dynamic load rating (C) from the thrust bearing given below. The calculated capacity (Ca) must be equal to or less than the catalogue rating (C).

Since, AGNEE Extruder gear drives are standardised with integrally - cast thrust bearing housing limiting the maximum size of thrust bearing for a particular model of gear reducer, a higher size gearbox may be required for accommodating a larger thrust bearing to satisfy the dynamic capacity.

THRUST BEARING DATA :
(With maximum possible bore in hollow output shaft which may be accommodated in the respective sizes of AGNEE standard double reduction parallel shaft extruder gearboxes in C. I. Case with integral thrust bearing housing).

THRUST BEARING DATA
SIZE	Spherical Roller Thrust Bearings (Standard Size)	Basic Dynamic Load Rating C (kN)	Out put Shaft
SIZE	Spherical Roller Thrust Bearings (Standard Size)	Basic Dynamic Load Rating C (kN)	Maximum Possible Bore Dia, Having Std. Key Way (mm)	Standard Bore Length (mm)
EX-112	29412 E	335	30	90
EX-125	29414 E	440	40	120
EX-140	29416 E	550	45	135
EX-160	29422 E	950	60	160
EX-180	29426 E	1250	75	200
EX-200	29428 E	1320	80	225
EX-225	29432 E	1700	90	240
EX-250	29436 E	2120	100	260

Example:

Driving Machine : Three Phase A.C. Motor.

Motor Power: 20 Hp or 15 KW

Diameter Of Motor Pulley : 5 inch

Diameter of Gear Box pulley: 9 inch

Gear Box Ratio: 12.6

Service Factor 1.5

Ambient Temperature: 30^oC

Screw diameter (Ds) 75 mm

WORKING Pressure ( Pa)300 bar

Thrust Bearing Life duration: 20000 hrs

Selection:

1. Selection of Reducer

· Input Speed to the gear box = 1440 X5/9 = 800 rpm

· Output speed of Gear box (Extruder screw rpm) = 800/12.6 = 63.6 rpm

· Required Torque (Nm)= 9550 X 15 ( 20 Hp) X 1.5/ 63.5 = 3383.9 Nm = 3.38 kNM

· From the “Rated output Torque “ table size 140 with Rated output Torque 3.49 kN at 12.6 ratio

2. Check for Thermal Rating:

· Let’s assume that the gear box is filled with cooling coil

Taking the thermal service factor at 30^oC & 100% running time as 0.9,

· Require Thermal Power (Kw) = 15/0.9=16.67 Kw

· From “Thermal Capacity” table, Thermal capacity = 116 KW. i.e. Thermal Capacity> Required Thermal Power. Hence the selection of the size is correct.

3. Check For thrust Bearings:

· The screw Diameter , working pressure, screw rpm and thrust bearing life expectancy are to be specified by the extruder manufacturer: In this case we have the date.

· Thrust Load (Fa) = 3.14 x (75)² X 300 / 4 x 10000 = 133 kN

· Thrust Bearing Capacity (Ca) = 1.06 x 133 x ( 20000 x 60 x 63.5/10000)^{3/10 =}516 kN

· From the “ Thrust Bearing Data” table, Dynamic Load Rating © = 550 kN
· i.e C>ca. Hence the selection of bearing is correct.

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