The Raw Milk Reception Dock (RMRD) is the primary intake point of liquid milk entry in dairies/chilling centres. It is specifically meant for the reception of milk brought in cans from village milk collection centres located over a wide area. The collection process starts from the village milk collection centres, groups of which are assigned to distinct milk truck routes. It is different from the bulk milk collection systems, which are also in operation in these dairies.

Bulk milk cooling tank is a large storage tank for cooling and holding milk at a low temp. till it gets transported. The BMC is made of stainless steel and used every day to store the raw milk on the farm in good condition and must be cleaned after each milk collection. To facilitate an adequate and rapid cooling of the entire content, tank is equipped with an agitator. On top of every closed milk tank, manhole is provided for thorough cleaning and inspection of the inner tank if necessary.

Road Milk Tankers are made up of Stainless Steel double walled construction with PUF insulation between the inner tank and the outer tank. The tank is elliptical in shape with single or multi compartment, outlets, manhole assembly with lid, Pressure relief valve, air vent and cleaning arrangement, ladder, catwalk and side protection channels. The milk discharge from the tank will be at the bottom through a discharge pipeline and butterfly valves.

Tanks for milk reception belong to the storage category like Raw milk tank, Processed Milk tanks, different types of milk storage tanks and vary in sizes from 500 to 50,000 litres. Tanks are made up of stainless steel double shell with mineral wool insulation in between. All tanks are fitted with agitators and monitoring and control equipment.

Silo tanks for milk reception belong to the storage category and used for Collection and reception of milk. They vary in size from 25,000 to about 1,50,000 litres and are made of stainless steel. They are often placed outdoors to save on building costs. The insulated tanks have a double shell with a minimum of 70 mm mineral wool insulation in between.

Milk contains some microorganisms after milking, their numbers increase during subsequent handling. The common milk microorganisms grow best between 20 – 40°C and Bacterial growth is invariably accompanied by deterioration in quality due to development of off flavors, acidity etc. Milk plate Chiller helps to maintain the quality of milk received in the Dairy/Chilling Center, it is chilled to 4°C by milk chiller. The chiller consists of stainless steel plates. Chilling is done by flowing milk from one side and chilled water from other side of the plates.

To increase milk safety for the consumer and increase keeping quality of milk and milk products by destroying spoilage causing microorganisms and enzymes that contribute to the reduced quality and shelf life of milk. Pasteurization can be done as a batch or a continuous process.

A Batch / Vat pasteurizer is a temp-controlled, closed vat. The milk is pumped into the vat, heated to the appropriate temp. and held at same temp. for the fixed time and then cooled. The cooled milk is then pumped out of the vat, for packaging or product making.

Plate Heat Exchanger (PHE) -In continuous process the milk is pumped from the raw milk tanks to continuous pasteurization system. The milk continuously flows from the tank through a series of thin plates that heat up the milk to fixed temp and further cooled to low temp. The milk flow system is set to make sure that the milk is thoroughly pasteurised, if not returned to balance tank.

Thermisation, is a method of sanitizing raw milk with low heat. Thermization is a generic description of a range of sub-pasteurization heat treatments that markedly reduce the number of spoilage bacteria in milk with minimal heat damage.The process is not used on other food products, and is similar to pasteurisation but uses lower temperatures, allowing the milk product to retain more of its original taste. 

Thermization involves heating milk at temperatures of around 63–65 °C for 15 seconds, while pasteurization involves heating milk at 71 °C for 15 seconds or at 63 °C for 30 minutes.  Thermization is used to extend the keeping quality of raw milk when it cannot be immediately used in other products, such as cheese. Thermization can also be used to extend the storage life of fermented milk products by inactivating microorganisms in the product.

This is the type of pasteurization that we most commonly see on cartons of milk, half-and-half and heavy cream. It produces a product that has a stable shelf life of up to two months! The UP method requires that the milk be held at 138°C for 2 seconds. Most commercial milk brands use this form of pasteurization since it is the quickest and cheapest.

Homogenization is a process that gives milk its rich, white colour and smooth texture. Milk that has not been homogenized contains a layer of cream that rises to the top of a glass.

The homogenization process involves reducing the size of the fat globules to 0.2 – 2 microns size which are dispersed evenly throughout the milk. Homogenization usually is achieved by pumping milk through small openings under very high pressure. Homogenization today is usually a two-step process. The first stage…pushes milk through small, tapered tubes or pores. As the diameter shrinks and the flow of milk remains constant, pressure builds up and fat globules break apart in the turbulence.

Cream Separator is machine used for separating and removing cream from whole milk; The separator consists of a centrifuge in the form of a rapidly revolving bowl containing a set of disks mounted on a spindle situated underneath the milk supply tank. As milk enters the bowl at the top, it is distributed to the disks through a series of openings, having speed of approx. 6,000 to 8,000 rpm, the heavier skim milk is thrown to the outer edge of the bowl and led off through an opening. The cream concentrates in the centre portion and moves to the cream outlet. The most efficient separators leave less than 0.01 percent fat in the skim milk.

Butter is defined is a fat concentrate product obtained by churning, cream, gathering fat into a compact mass and working it. Butter is made exclusively from milk or cream with or without common salt and colouring matter and contains not less than 80% fat. In butter, fat is present in continuous phase and water is present in dispersed phase. This phenomenon is known as phase inversion.

Ghee is clarified butter fat. It is prepared on both small and large scale, Deshi method of ghee making comprises more than 90% if Indian Ghee production. The Ghee is prepared b fermenting whole milk to curd, churning the curd to butter and boiling down the latter to ghee. Ghee is the richest source of animal fat in vegetarian diet. It supplies 9 K. calorie energy/gm. It has long keeping quality under tropical storage conditions. In India, Ghee is prepared form Makhan (deshi butter).

Yogurt is a fermented milk product that contains the characteristic bacterial cultures. The main ingredient in yogurt is milk. The type of milk used depends on the type of yogurt – whole milk for full fat yogurt, low fat milk for low-fat yogurt, and skim milk for non-fat yogurt. Other dairy ingredients are allowed in yogurt to adjust the composition, such as cream to adjust the fat content, and non-fat dry milk to adjust the solids content. The solids content of yogurt is often adjusted above the 8.25% minimum to provide a better body and texture to the finished yogurt.

Paneer is a fresh cheese common in India made by curdling milk with a vegetable-derived acid, such as lemon juice. Paneer is prepared by adding citric acid to hot milk to separate the curds from the whey. The curds are drained in muslin or cheese cloth and the excess water is pressed out. The resulting paneer is dipped in chilled water for 2–3 hours to improve its texture and appearance. From this point, the preparation of paneer diverges based on its use and regional tradition.

Ice cream is a frozen blend of a sweetened cream mixture and air, with added flavours. A wide variety of ingredients are allowed in ice cream, but the minimum amounts of milk fat, milk solids (protein + lactose + minerals), and air are defined. There are well-defined labeling requirements for the types of flavors used (natural and artificial).

Ice cream is sold as hard ice cream or soft serve. After the freezing process only a portion of the water is in a frozen state. Soft ice cream is served directly from the freezer where only a small amount of the water has been frozen. Hard ice cream is packaged from the freezer and then goes through a hardening process that freezes more of the water in the mix.

Clarifiers are settling tanks built with mechanical means for continuous removal of solids being deposited by sedimentation. A clarifier is generally used to remove solid particulates or suspended solids from liquid for clarification and/or thickening. Concentrated impurities, discharged from the bottom of the tank are known as sludge, while the particles that float to the surface of the liquid are called scum.

Ghee from the settling tank is fed through the inlet placed at the top of ghee clarifier. Separation of the ghee residue from the ghee takes place in a solid wall bowl, under the influence of centrifugal force. The residue thus separated is collected in the sludge space of the bowl and clarified ghee flows through the clarifier outlet.

The sterilization is the process of heating to a high temperature (more than 100°C) for specific time to kill almost all bacteria. The sterilized milk can be stored at room temperature for a long period of time.

The sterilization of milk has the following characteristics. • Temperature more than 100°C is used in the process. • No chilling is required for storage. Excellent storage life at room temperature. • High operating pressure is employed to prevent milk from boiling at the processing temperature.

Methods of sterilization In general there are two methods of sterilization. Conventional method: Packaging is done before heat treatment. The processing is usually carried out at 105-110°C for 30-45 min. It is also known as In-bottle sterilization. UHT or aseptic method: Packaging is done after heat treatment. The ultra high temperature short time (UHTST) and very high temperature short time (VHTST) processes come under this category. The processing is at 135-150°C for 1-20 seconds. Then the commodity is packed aseptically.

Clean-in-place (CIP) is a method of cleaning the interior surfaces of pipes, vessels, process equipment, filters and associated fittings, without disassembly.

Up to the 1950s, closed systems were disassembled and cleaned manually. The advent of CIP was a boon to industries that needed frequent internal cleaning of their processes. Industries that rely heavily on CIP are those requiring high levels of hygiene, includes dairy, beverage, brewing, processed foods, pharmaceutical & cosmetics. The benefit to industries that use CIP is that the cleaning is faster, less labour-intensive, and more repeatable, and poses less of a chemical exposure risk.

Chilling Plant is a machine that removes heat from a liquid via a vapour compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool equipment, or another process stream. Chillers may use hermetic scroll, or semi hermetic screw, or centrifugal compressors.

Chilled water is used to cool and dehumidify air in mid- to large-size commercial, industrial, and institutional facilities. Water chillers can be water-cooled, air-cooled, or evaporatively cooled. Water-cooled systems can provide efficiency and environmental impact advantages over air-cooled systems.

Glycol chillers are industrial refrigeration systems that use a type of antifreeze called glycol, mixed with water, to lower the freezing point in the application of the chilling system. Glycol is a class of organic compounds that belong to the alcohol family. When mixed with water and pumped through the pipes of a chilling system, glycol serves to slow the rate of freezing. It helps maintain temperature consistency in the application. Some glycol products also work to inhibit corrosion and bacterial growth within the pipes of the chilling system.

Refrigeration, or cooling process, is the removal of unwanted heat from a selected object, substance, or space and its transfer to another object, substance, or space. Removal of heat lowers the temperature and may be accomplished by use of ice, snow, chilled water or mechanical refrigeration. The Refrigeration basic principle is that with the aid of a heat pump, the refrigerant is being compressed to the condenser and capillary tube thus increasing its temperature (50-60°C) and pressure (750 kPa) in the refrigerator being cooled down by the condensing unit to 32°C depending the existing ambient temperature.

What Are the Different Types of Refrigeration Systems?

• Mechanical-Compression Refrigeration Systems. The most widely used refrigeration cycle method is mechanical compression. …
• Absorption Refrigeration. …
• Evaporative Cooling. …
• Thermoelectric Refrigeration.

Refrigeration systems use basic physics to move heat energy out of one area and into another, leaving the first area cooler than it was before. Artificial cooling systems keep industry running, and many of these systems use anhydrous ammonia as a refrigerant.

In very large cooling systems, like those in food processing facilities, ammonia is a common choice of refrigerant. There are three major reasons for choosing ammonia as a refrigerant:

• Effective and efficient for large systems.
• Ammonia breaks down quickly minimizing potential environmental impact.
• Any spill or accidental release can be quickly identified, due to its strong odour.

This systems are operated on the “vapor compression” principle which simply means that the heat being removed and transported to another location is accomplished by the alternate evaporation and condensation of a refrigerant usually referred to as a Freon. This type of refrigerant plant is controlled by a compressor which varies the pressure on the refrigerant. The Freon gas which transfers heat in a refrigerating machine or heat pump, has the ability to absorb heat when it changes state from a liquid to a gas. Similarly, when the Freon changes back into a liquid it releases its heat much like wringing out the sponge. It is this process that allows us to absorb heat from ground water, concentrate it through the heat pump system, and deliver it to the home in the form of warm air.

A cooling tower is a heat rejection device, which extracts waste heat to the atmosphere though the cooling of a water stream to a lower temperature. … Common applications for cooling towers are providing cooled water for air-conditioning, manufacturing and electric power generation.

Cooling towers are a special type of heat exchanger that allows water and air to come in contact with each other to lower the temperature of the hot water. During this process, small volumes of water evaporate, lowering the temperature of the water that’s being circulated throughout the cooling tower. There are three main types of cooling towers that are defined by how water or air pass through them. These types include cross-flow, counter-flow, and hyperbolic. There are also two varieties classified solely on airflow, known as induced draft and passive draft cooling towers. Cooling towers should be located with their small side toward the prevailing wind. The gives both long sides an equal intake of fresh air.

A cold storage unit incorporates a refrigeration system to maintain the desired room environment for the commodities to be stored. The system works on two principles:

1. Vapour absorption system (VAS), and
2. Vapour compression system (VCS)

VAS, compared to cost, it is quite economical in operation and compensates the higher initial investment. Wherever possible such a system should be selected to conserve on energy and operational cost. However, it has its own limitations when temperature requirement is below 10°C and many of the fruits and vegetables except seeds, mango, etc. require lower than 10°C for long storage.

VCS is comparatively cheaper than VAS. There are three types of VCS systems available depending upon the cooling arrangements in the storage rooms i.e., diffuser type, bunker type and fin coil type.

Diffuser type is comparatively costlier and is selected only when the storage room heights are low. The operational cost of such units is also higher.

Bunker type is the cheapest and is preferred when storage room heights normally exceeds 11.5 m. Its operational cost is also low. Fin coil type, about 5% costlier than the bunker type, is very energy efficient with low operational cost and higher space availability for storage of produce. Such system is used for units with room heights of 5.4m onwards.

A boiler or steam generator is a device used to create steam by applying heat energy to water. A pressure vessel that provides a heat transfer surface (generally a set of tubes) between the combustion products and the water. A boiler is usually integrated into a system with many components. Boilers are used to produce steam. The generation part of a steam system uses a boiler to add energy to a feed water supply to generate steam. The energy is released from the combustion of fossil fuels or from process waste heat. There are two basic types of boilers: fire-tube and water-tube. The fundamental difference between these boiler types is which side of the boiler tubes contain the combustion gases or the boiler water/steam.

It is the efficient and cost-effective way to generate hot water instantly. Hot Water Generator can be pressurized or non-pressurized depending on the required temperature of water. Hot water generator uses this principle to heat water above 100°C by applying pressure on the water without changing its liquid state.

Features

• Custom units built to order with capacities up to 5,000 gallons.
• Meets or exceed thermal efficiency and/or standby loss
• Steam or Water Boiler options available.
• Available in space saving vertically or horizontally models.

Heating Options for Hot Water Generators

• Liquid Fuels – Light oil / Heavy oil
• Gaseous fuels – LPG or CNG
• Solid Fuels – Coal or Wood or Briquettes
• Electrical operation – Element heaters or Electrodes

Advantages of Hot Water Generators

• Fully automatic unit
• Trouble free operation
• Outside the purview of IBR.
• High system efficiency
• The minimum site works and ease of installation.
• Can operate on the variety of fuels as per local availability.