Lesson 13 Process schedule

13.1 Introduction

Process schedule is one of the important activity of planning, before diverting raw material to different section for product manufacturing. It is prepared well in advance to give instructions to boiler operator, refrigeration plant operator, different process section incharge to plan for the activity of different unit operations for processing the material to have smooth operation of the process. It also helps to prevent product losses and to have efficient use of equipments, energy and water.

The benefits of scheduling include:

  • Process change-over reduction

  • Inventory reduction and levelling

  • Reduced scheduling effort

  • Increased production efficiency

  • Labour load levelling

  • Accurate delivery date quotes

  • Real time information

13.2 Planning for process schedule

Preparation of process schedule is one of the important tasks in food plant operation for an engineer/technologist in order to prevent losses in terms of manpower, energy, services, and time. A well planned time schedule will help in preventing losses as well aid in routine work viz. Maintenance, breakdown, establishment etc.

After careful consideration of food building planning mentioned above, a process scheduled layout is drawn. Process scheduling means arranging the flow of products through various operations in the plant in such an order that maximises use of all labour and equipment, and the processing of the products is accomplished in the shortest possible time with minimum delays between processing of different products.

First of all “Basis of Plant Layout’ is drawn according to item of manufacturer to decide definite line flow. To this skeleton layout are added as other information, such as operating rates, storage capacity, raw material required, man power required etc. as each section of plant is considered in relation to the equipment available.

Planning for operations involved in processing of any food product has to be done in advance so that maximum use is made of men and material with little waste of time. Process schedule which is more or less work plan ensures that the proposed operation will run smoothly. It provides the basic information from which schedule of service requirements and list of equipment can be made. Time and operation graph can be made which will indicate at what time particular operation has to be performed. It may be noted that all operation for manufacture of any particular food product can not be started at time. There must be a sequence for performing an operation in the plant and that is why the process schedule is required.

The features of the plant considered during preparation of process schedule are:

· Reception capacity,

· Unit processing cost,

· Frequency of CIP,

· Installed capacity of the plant,

· Handling capacity of the plant,

· Running hours and Idol time of plant,

· Quantity of material received in different season,

· Capacity of the various equipments installed for the processing and production purpose viz. PHE, SEPARARTOS, PUMPS, CATLES, VAT, etc;

· Capacity of the services and providing machines viz. Air compressor, refrigeration, boiler, water, ETP, etc;

· Product dispatch timing

Example: Process schedule of a milk-processing plant handling approximately 1.5 lakh lit of milk in morning and evening:

Milk is received two times in a day approximately 82,000 lit in evening and 68,000 lit in the morning.

Considering the processing capacity of the plant 20,000 lit /hr.

L 13 Fig.1

L 13 Fig.2

Last modified: Wednesday, 5 March 2014, 4:30 AM