Material Holding, Feeding and Metering

UNIT 9. MATERIALS HANDLING

Task 1. List factors that must be known when a material handling system is designed. Compare your list with that of your partner.

This is how we express our opinion in English. Study this table.

Task 2. Look at the picture. What are these made of? Match the photos with these materials.

aluminum ceramic fiberglass graphite nylon

polycarbonate rubber steel titanium

Task 3. Work in pairs. What are the most important properties of the materials in the box? Discuss with your partner.

B) listen again and complete the dialogue.

● I’m (1) _____ the rope. I’m (2) _______ it. Is it (3) ______?

○ No, it (4) ______.

● That’s right. It (5) __________.

Task 5. Read and translate the following text.

Material Holding, Feeding and Metering

The movement of material from the place where it is to place where it is needed can be time consuming, expensive, and troublesome. The material can be damaged or lost in transit. It is important, therefore, that it be done smoothly, directly, with the proper equipment and so that it is under control at all times. The several factors that must be known when a material handling system is designed include:

1. Form of material at point of origin, e.g., liquid, granular, sheets, etc.

2. Characteristics of the material, e.g., fragile, radioactive, oily, etc.

3. Original position of the material, e.g., under the earth, in cartons, etc.

4. Flow demands, e.g., amount needed, continuous or intermittent, timing, etc.

5. Final position, where material is needed, e.g., distance, elevation differences, etc.

6. In-transit conditions, e.g., transocean, jungle, city traffic, inplant, etc., and any hazards, perils, special events or situations that could occur during transit

7. Handling equipment available, e.g., devices, prices, reliability, maintenance needs, etc.

8. Form and position needed at destination

9. Integration with other equipment and systems

10. Degree of control required

Material handling may be divided into classifications or actions related to the stage of the process. For some materials the first stage is its existence in its natural state in nature, e.g., in the earth or ocean. In other cases the first stage would be its receipt at the factory’s receiving dock. Subsequent material handling actions might be: holding, feeding, metering; transferring, positioning; lifting, hoisting, elevating; dragging, pulling, pushing; loading, carrying, excavating; conveyor moving and handling; automatic guided vehicle transporting; robot manipulating; identifying, sorting, controlling; storing, warehousing; order picking, packing; loading, shipping.

Material may be in solid, liquid, or gaseous form. Solid material may be in end-product shapes or in intermediate forms of slabs, sheets, bars, wire, etc., which may be rigid, soft, or amorphous. Further, each item may be unique or all may be the same, allowing for indiscriminate selection and handling. Items may be segregated according to some characteristics or all may be commingled in a mixed container. They might have to be handled as discrete items, or portions of a bulk supply may be handled. If bulk, as coal or powder, their size, size distribution, flowability, angle of repose, abrasiveness, contaminants, weight, etc., must be known. In short, before any material can be held, fed, sorted, and transported, all important characteristics of its form must be known.

Devices used to hold material should be selected on the basis of the form of the material, what is to be done to it while being held (e.g., heated, mixed, macerated, dyed, etc.), and how it is to be fed out of the device. Some such devices are tanks, bins, hoppers, reels, spools, bobbins, trays, racks, magazines, tubes, and totes. Such devices may be stationary – either with or without moving parts – or moving, e.g., vibrating, rotating, oscillating, or jogging.

The material holding system is the first stage of a material handling system. Efforts should be made to assure that the holding devices never become empty, lest the entire system’s flow stops. They can be refilled manually or automatically and have signals to call for refills at carefully calculated trigger points.

The feeding and metering devices selected depend on the above factors and the properties of the material. Some, but not all, possible devices include: pumps, dispensers, applicators; feed screws, reciprocating rams, pistons; oscillating blades, sweeps, arms; belts, chains, rotaries, turnables; vibratory bowl feeders, shakers; escapements, mechanisms, pick-and-place devices.

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