Loss In Weight Feeder

Over View :Loss in-weight feeders operate on the principle of controlled loss-in-weight. The proposed system comprises of a Weigh Hopper, Loadcells, Screw Conveyor with motor and associated control electronics. The Weigh Hopper and Screw Conveyor are mounted on 3 Nos. of Loadcells. The Loadcells are connected to a controller through a junction box.

The material from the storage hopper is fed to the weigh hopper, which is controlled by a gate. A small screw feeder is mounted below this weigh hopper. The weigh hopper and screw feeder are mounted on high precision Loadcells and the output of the Loadcells are summed in a junction box and fed as an analog input to the controller. The controller calculates the rate, compares with the set rate and feeds the corresponding 4-20mA signal to the VVVF drive so as to control the speed of the motor of the screw, thereby controlling the rate of discharge.

The controller is programmed with a set high and set low values of material weight in the weigh hopper. Once the set value is achieved, the gate of the storage hopper is closed and the screw conveyor runs at the set rate value and the system works as explained in the "Loss-In-Weight" principle i.e, gravimetric mode. Once the material reaches set low value, the system switches over to operating in volumetric mode i.e. the screw runs in a constant speed and maintains at the previously running speed. At the same time, the material fed to the weigh hopper, until the weight of material in the weigh hopper reaches set high value. On reaching set high value the gate of the storage hopper closes and the system switches from volumetric mode to the gravimetric mode of operation.

Weigh FeederWeigh Feeder

Over View : Movement of bulk material is an essential feature in modern industrial processes. The simplest and fastest mode of transportation of such material is to convey them over a moving belt. In this operation the precise weighing of material, as it moves, has assumed a key role in process industries. Hence weigh feeder is a closed loop control system in which a precise control can be had over the flow of materials, which has indicating, totalizing and controlling instruments and circuits.

The Weigh Feeder is a custom engineered equipment that finds application in continuous bulk proportioning of solids. This gravimetric feeder is operated by a closed loop control system enables feeding at a controlled rate and exercises precise control over rate of flow based on a micro controller.

The system is capable of accepting external signals from other controllers or from the process computer, depending on the extent of plant instrumentation. These gravimetric feeders are in operation in steel, cement, fertilizer and chemical industries. Each system consists of control and local panels, loadcells to measure the instantaneous load, a digital tacho to sense the speed of the belt and a belt feeder conveyor shaft is driven by an AC motor coupled through the gear box

solid flowSolid Flow Meter

Over View : In the proposed system, the flow meter is fixed after the air slide. The material from the storage hopper flows out through the dozing valve and comes on to the impact flow meter. The output from the load cell of the impact flow meter which is a mill volt signal is taken to a high precision electronics. The controller has two high precision analog to digital convertors that accepts the load cell signal and also the signal of the position of the dozing valve.

Operational sequence : The set rate of feed is entered into the controller through its key pad. This set point can also be set via a computer which interfaces to the RS232 port of the controller. When the start command is given, the controller gives command to the gate to open and also the output of 4-20mA goes to the drive to open the dozing valve. The dozing valve opening position is got as position feedback from the potentiometer inbuilt in the dozing valve. The rate is calculated by the load on the flow meter. In case this feed rate is lesser than the set feed rate then, the dozing valve shall be opened further to increase flow rate else to decrease flow rate it is closed further. The feed rate is controlled by the opening and closing of the dozing valve.

When the stop command is given, the controller will first command the pneumatic slide gate to close. After this command is given, the dozing valve is closed

Advantages of IPA Batching System

  • Quick installation combined with high accuracy.
  • Password protection
  • Programmable through key pad
  • Mimic board & push button on the desk for easy operation
  • Coarse feed and fine feed facility.
  • Manual/semi auto mode of operation.

Bagging SystemBagging System

Over View : Bag Filling machine works on pre-weigh & dump principle. The bag filling machine consists of a weighing hopper with dual feed flow gate, a discharge hopper and suitable bag clamping arrangements

The filling sequence starts with a START input from the operator via push button on the controller. The controller automatically tares the gross weight to obtain a net weight of Zero. The material is then fed into the weigher hopper via a two speed flow gate which controls the rate at which it is fed. The controller compares the actual weight with the target weight settings. When the main/coarse feed setting is reached the main feeder of the sector gate is latched and feeding continues in the fine/dribble feed mode. The material is fed in the fine feed mode until the final weight minus in-flight value is reached, after which the fine feeder is closed. Once the feeding is stopped a settling time is given after which the end of batch is signaled and the totalizer and bag counter is updated automatically. This weighed quantity is immediately transferred into the discharge hopper and the weighing hopper gets ready for the next weighing.

The bag is clamped to the bag holder by a pneumatically operated clamping arrangement. Necessary safety interlock is provided to ensure that the material is discharged into the bag from the discharge hopper only if the bag is clamped. Once the pre-weighed quantity of material in the discharge hopper is completely discharged, the bag is declamped and the discharge hopper gets ready to receive the next weighed quantity from the weigh hopper. This cycle continues. Note: The slat conveyor for carrying the bag and the required stitching machine can be provided optional at extra cost.

  • Belt Conveyors
  • Bucket Elevators
  • Level Switches
  • Weighing Scales
  • Weighing Systems
  • Plant Automation

 

© 2011 Dynacraft Inc. All Right Reserved