DIFFERENT TYPES OF FEEDER'S

 There are different types of material conveying systems , in which i will be talking mostly on belt conveyor systems which is my area of expertise. As discussed earlier the cargo is unloaded from different types of machinery namely wagon tippler , Grab ship Unloader , Harbor mobile crane etc . These equipment unloades the different types of cargo with respect to handling methods and the machinery designed to handle the type of cargo with respect to load capabilities. The first step in unloading and storing process is that the unloaders unloades the cargo in to the hopper , this was discussed earlier. From the hopper how will the cargo flow happens?

There comes this equipment called feeder . As the term defines itself , the feeder feeds the cargo to the conveyor. The feeder can be a variable speed one or the fixed speed one with respect to the requirement of the feeding and the design of the plant.

The various types of feeder can be

1)    Apron feeder

2)    Feeder belt

3)    Vibro feeder

Apron feeder is the equipment which is designed to withstand high impact loads. That is the reason they have been used under the hopper where wagon tippling process is done and where the cargo density is much higher .

Construction of apron feeder

Apron feeder consist’s of a long chains of closed ends separated by a distance of width say 2000 mm (Can be of any width depends on the location and its design ) , these chains are agglomeration of links as we see in the normal chains in every day life. These links are connected to each other with long and heavy bolts usually more than 36mm in dia and fastened with nuts. These links have holes on their top to accommodate the sitting of pans and fastening them with bolts. So on both sides say left and right we have two chains on that, apron pans will sit. The apron pans are the large pans of heavy steel structure which are designed to withstand the loads from different height. These pans are made of Sail hard plate which is having a hardness of 200 hrb. These pans are having high abrasion resistance to withstand the wear from the cargo. This apron feeder is driven by an electric motor , the gearbox is connected to electric motor via a spring coupling ,the gearbox output shaft is connected to the pinion gear via an gear coupling. The pinion rotates the bull gear , which is a large gear connected to the apron feeder. The chains as was described earlier were moved on heavy rollers , this same type of arrangement can be seen in the excavator crawler chains.

                                 (apron feeder pans from the inside view and the bolts fixed )

Contruction of feeder belt

Feeder belt is similar to that of conveyor belt , it is a short conveyor consists of only two pulley’s , a head pulley which also acts as a  drive pulley and discharge pulley and  a tail pulley .

 The feeder belt is driven by an electric motor followed by geabox. The motor and gearbox is connected by a high speed coupling and the gearbox output shaft and the pulley is connected by an low speed coupling . The high speed coupling is a fluid coupling and low speed coupling is a gear coupling. The fuild coupling has different types and low speed couplings  also has a wide variety of couplings. In upcoming posts I will put forward the type of couplings I saw and their usage. The feeder belt speed can be adjusted for the requirement of TPH , this can be done by a drive and PLC logic system . To adjust the sway in feeder belt there are options like screw take up or hydraulic take up provided depending on the design , location and usage of the feeder belt.

(the tensioning cylinders on both sides of tail pulley to provide tension and to adjust belt sway)

Construction of vibro feeder

Vibro feeder is an equipment which is a large tray on which the cargo fall’s. The tray moment takes place with respect to vibration. 

The question is how does the vibration happens ?. Well like the above equipments enlisted , this also has a prime mover that is an electric motor. This vibro feeder can also be a variable speed one, if the design constitutes a drive system. The motor is connected to a cardon shaft with a rigid coupling . The cardon shaft has a knuckle joint to accommodate different loads .

                                        (the cardon shaft connected to motor and gearbox )

 The cardon shaft is connected to gear box, the gearbox is mounted onto the tray base directly which we described earlier. The gearbox output shaft there are weights mounted and fixed at an angle. When the motor rotates and the power transmission takes place through the cardon shaft , the weights mounted on the output shaft of the gearbox rotates in different directions providing vibration. When the motor rotates slowly the vibration will be less and when the motor rotates fast the vibration will be more owing to more TPH discharge.

      

        (the gearbox mounted on the base of feeder and the arrangement of weights on shaft )