Revised Web Page - 2017 July 14

Coal Feeder

RULA design, manufacture and supply belt type coal feeders for a wide range of applications

Description

The purpose of the RULA coal mill feeders are to supply a specified coal capacity within the accuracy required. Our feeders are the only locally developed, designed and manufactured meaning that we can easily customize the design to suit your specific application. This ensures beneficial cost and lead-times.

Operating principle and accuracy

A column of coal is delivered to the feeder via the inlet spout and rests on the feeder belt.

The head-end pulley turns the belt, thereby dragging the coal at the bottom of the column out. This coal passes over the belt scale (also locally designed and built), which measures the coal mass. A controller then calculates the coal capacity by integrating the measured mass and the measured pulley speed. On-site truck tests have shown our feeders to have an accuracy of at least 2.5%.

Codes and standards

If required our coal feeders can comply with the Boiler & Combustion System Hazards (NFPA85) Code. The code requires coal feeders to withstand explosions of 344 kPa. Our in-depth Finite element designs ensure that we can optimize material strength and costs.

Each coal feeder system is unique. We design our coal mill feeders to integrate elegantly into the plant, while meeting the capacity and other technical requirements.

Design Features

- The reinforced side wall belt, has a V-groove centrally-located on the underside of the belt to assist with alignment.

- The rubber lagged head pulley with and V-groove ensures that the belt does not slip.

- The take up pulley is self-cleaning causing any material caught in the pulley to spiral outwards.

- Two belt misalignment switches, a blocked chute detector, a material on belt switch and a temperature transmitter are standard safety interlock devices fitted to our feeders.

- A tail pulley speed sensor is used to measure the belt speed for use in the speed controller.

- Thru put capacity readings are easily obtainable from the control panel display.

- A seal air deflector plate ensures that the seal air does not impinge on the belt.

- A chain scraper at the bottom of the feeder, rotates in the opposite direction of the belt, pushing any spilled material out through the discharge chute.

Operating and Maintenance

- Multiple access hatches simplify maintenance on the coal feeder.

- The head and tail ends each have an access door which can be opened and closed without the use of tools.

- Sight glasses are installed on the head and tail access doors.

- Each sight glass can be cleaned from the inside by means of an air nozzle and ball valve arrangement.

- Internal light fittings are provided at the head and tail end of the feeder.

System Integration

Rula' engineers have the knowledge and experience to optimise the upstream coal supply, which is a critical part of feeder design, making effective use of radial stress fields to reduce feeder loads and in avoiding high start-up loads due to vertical stress fields.

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