DAIRY PLANT DESIGN AND LAYOUT

Module 4. Design aspects of dairy plant

Lesson 23
MATERIAL HANDLING

23.1 Introduction

The modern dairy plant today is faced with continually rising labour cost, higher prices of milk, equipment and suppliers. As a result the progressive plant operator and equipment manufacturers have given considerable thought to the development and application of automatic equipment and controls to reduce man hours per unit of product, decrease product and container losses, and to increase overall plant efficiency. As operating costs increase more product per man-hours at a lower cost per unit must be realized to maintain a profitable operating balance. Progressive dairymen today are recognizing the need for the development and use of modern material handling methods and equipment for the materials handling phase of any dairy plant operation.

In setting up operations and designing material handling systems, it is essential that an analysis be made of the entire plant product flow. This analysis show the raw product in, the major product movement, the specialized or branch movements, the processes, the storages for the various products, and the out movements. It is particularly important to note the areas where high density traffic is found. It is also important to note the sequence of movements and provide for them so that the whole operation will move forward smoothly. The designer should take advantage of the many new material handling methods and equipment, utilizing each one where it is crates, cans, etc. can be moved by means of chain conveyors or they may be moved by trucks or pallets. Surprisingly enough, there may be places where some handling can best be made by means of manual labour.

Material handling systems for food products should be carefully selected so that it will not be affected by temperature change or severe vibrations. The material handling system should be simple in design, having ease of lubrication, corrosion resistant and low maintenance. The use of automatic stopping and starting controls, speed regulators, switches, and over-load safety devices are all important. Fig. 23.1 shows concept of material handling system in the dairy plant.

23.2 Material Handling Systems for Dairy Plant

The key raw material for any dairy plant is milk. The raw milk can be procured in different vessels, generally cans of 5, 10, 20 and 40 liters capacity of aluminum, stainless steel, food grade plastic can be used (Fig. 23.2 (a), (b) and (c)). The milk can be procured in cans by truck (Fig. 23.7) or in road tankers (23.8). The milk can be transported for long distance by rail tankers. To reduce microbial load and to increase shelf-life of the milk cold chain is maintained during handling and procurement (Fig. 23.4).

The milk cans received at dairy plant can be handled by gravity or chain conveyors (Fig. 23.3 (a), (b)). The milk received by road tankers can be directly pumped to the silo (Fig. 23.6). The viscous and powdered products can be conveyed by screw type of conveyors (Fig. 23.3 (c)).

The boxes and blocks (cheese blocks) can be transferred from one place to another place by pallets and it can be racked and stacked in the rooms. The powdered products can be conveyed by blowing the air or by suction using air ducts. The material handling systems for different products can be designed using automation, so that material can be handled with minimum labour and damage to the product.

Fig. 23.1 Concept of material handling in the dairy plant



Fig. 23.2 Milk cans



Fig. 23.3 Conveyors for dairy plant



Fig. 23.4 Bulk milk coolers



Fig. 23.5 Storage tanks for milk



Fig. 23.6 Milk silo



Fig. 23.7 Trucks handling milk cans



Fig. 23.8 Road milk Tanker



Fig. 23.9 Pallet for racking and stacking