DAIRY PLANT DESIGN AND LAYOUT

Module 4. Design aspects of dairy plant

Lesson 18
SERVICE ACCOMODATION

18.1 Introduction

Siting of auxiliary services mean proper placing of service sections providing auxiliary services such as steam, refrigeration and electricity to the dairy plant. In small and medium capacity plant, it is practicable to provide these rooms within the main building. But in large plants, it is better to group these rooms in a separate building. The arrangement of rooms where secondary equipment such as boiler, compressor, evaporators, condensers and workshop equipments are installed should be such, so as to allow easy supervision. Equipment, such as brine pumps, chilled water pumps, hot water circulating units and control should be located in a separate or beneath the floor away from processing section.

18.2 Boiler Room

The boiler house, if placed in the main building, it should then be placed near the main areas utilizing steam, such as mil drying and condensing. Usually boiler is installed on the ground floor with access from one side for the removal and replacement of the plant when required. The room for boiler accessories should be close to the boiler house. The discharge of solid fuel and removal of ash are dusty operations. Therefore, it is desirable to place the boiler section in such a way that the process room is not affected by it. This point has to be considered carefully if solid fuel is used.

18.3 Refrigeration Machinery Room

Refrigeration is a costly affair. Economy should be considered in minimizing the length of service lines by locating it centrally, and near the place where cooling is required. In small and medium capacity plants, the condensing unit for the cold store may be placed adjacent to it; but in large plants or where the products include ice-cream, the equipment involved will require a special room. This should be placed as close to the load areas as possible because in these and other applications of direct refrigeration, the longer the service lines, the greater the cost of refrigerant required to charge the system and greater the running cost.

Indirect refrigeration using chilled water is mainly concerned with precooling of raw milk and final cooling of pasteurized milk. In small and medium sized dairy plants, it is possible to place the compressor and chilled water tank with those for direct refrigeration. In large plant, it is better to site compressor near the section concerned.

An energy exist must be provided in the compressor room. Care for installation or replacement of equipment should be taken in view and this would decide to site the compressor room on ground floor with easy approach to room 8in case of emergency.

18.4 Electricity

If the electricity is purchased from outside, i.e., State Electricity Board or Municipal Undertaking, then high or low voltage intake will present no unusual siting problems. In case the electricity is to be generated, the power house should then be located close to the boiler house for supervisory reasons. The switch rooms should be centrally located to economise in wiring. A large plant may have moré than one switch room.

The siting of switch room may be more difficult to decide especially in a multistory building. If all or most of the motor starters are housed there, power cables must be taken to the equipment concerned and control circuits must be brought in from all the operating stations. Thus, the switch rooms must be located as central as possible to economise in wiring.

18.5 Workshops and Garages

Workshops include three main sections which will carry out routine repair and maintenance work of dairy in respect of Civil Engineering, Mechanical Engineering and Electrical Engineering. A small dairy will have one large workshop having three sections under one roof. For medium and large dairies, there will be separate workshops for electrical, mechanical and civil works, respectively. All workshops can be grouped and placed in a separate building near the plant.

Garages are generally of two types, one meant for parking cars tankers or other vehicles, the second one is for repairs. Parking garages are located near offices or place of work. If the plant has its own fleet of vehicles, then garages have to be erected at a suitable place on the site. The garages may be placed close to workshop with facilities for washing the vehicles and for lubrication services.

Residential accommodation for key workers or essential service personnel may be constructed near the plant side but quite separate from plant building.