Dairy evaporator

Types of Dairy Evaporator

The dairy evaporator is a device used in the concentration of liquid foods such as milk. Before discussing the types of dairy evaporators, it is important to understand what the dairy evaporator does.

The evaporator works by removing a large part of the water contained in milk so that the milk can be concentrated. The process of removing water from milk is done by heating the milk to a certain temperature and then creating a vacuum to ensure that the water contained in the milk can be converted into steam.

The evaporator is used to ensure that milk products retain their nutritional value. By concentrating milk, the dairy industry can reduce transportation costs and meet the increasing demand for milk products.

Now that we know what the dairy evaporator is used for and what it does, here are the different types:

• Falling Film Dairy Evaporator: This type of dairy evaporator is popular because it is energy efficient and uses a low boiling point. In the falling film evaporator, the milk is heated and then distributed to vertical tubes. The tubes contain a heating medium that helps to vaporize the water. One of the key features of this type of evaporator is that it has a milk film that falls onto the tubes' walls. This film is responsible for providing a consistent and uniform coating that helps to reduce the heat transfer.
• Forced Circulation Dairy Evaporator: In this type of evaporator, a pump circulates the milk through the heating and cooling sections. This circulation helps to create a constant flow, which in turn reduces the temperature difference between the milk and the heating medium.
• Batch Type Dairy Evaporator: This is the oldest type of evaporator, and it is still used today in many small-scale dairy operations. The batch type dairy evaporator works by heating and holding milk in one vessel. The evaporation process takes place until the desired concentration is reached.
• Multiple Effect Dairy Evaporator: This type of dairy evaporator is designed to be energy efficient and to maximize the evaporation process. The multiple effects dairy evaporator consists of two or more evaporators that are connected. This connection allows the steam produced by the first evaporator to be used as a heating source for the second evaporator.

Specification and maintenance of dairy evaporator

Specifications of dairy evaporators include the following:

• Feed flow rate:

  This is the amount of liquid feed that enters the evaporator every hour. It is measured in kg/h. For instance, a small evaporator may have a feed flow rate of about 1000 kg/h, while larger ones may have about 5000 kg/h or more.

• Concentration ratio:

  This is the ratio between the total amount of solids or other constituents in the liquid feed and the total amount of solids or other constituents in the output concentrated liquid. For example, if the feed has 10% solids and the output has 30% solids, the concentration ratio will be 3:1.

• Heating surface area:

  This is the total area of the evaporator surfaces that come into contact with the heating medium, such as steam. It is measured in square meters (m2). A larger heating surface area can increase the evaporation rate and improve heat transfer efficiency.

• Operating pressure:

  This is the pressure at which the evaporator operates. It is measured in bars or Pascals. The operating pressure can affect the temperature of the heating medium, the boiling point of the liquid, and the evaporation rate.

• Energy consumption:

  This is the amount of energy required to operate the evaporator. It is measured in kilowatt-hours (kWh) or megajoules (MJ). Energy consumption can be influenced by factors such as the heating surface area, the temperature difference between the heating medium and the liquid, and the efficiency of the evaporation process.

To maintain dairy evaporators, the following should be done:

• Regular cleaning:

  Evaporators should be cleaned on a regular basis to get rid of any deposits or build-ups that can affect their performance. Cleaning procedures differ based on the type of evaporator and the kind of deposits present. However, cleaning solutions and methods that won't harm the evaporator's materials or components should be used.

• Inspecting gaskets and seals:

  Gaskets and seals are to be looked at in a regular basis to check for any signs of wear, damage, or leakage. They are important components that help to maintain pressure and prevent the escape of vapour or liquid. If there are any issues, replacements or repairs should be made immediately.

• Tightening bolts and fittings:

  Loose bolts and fittings can cause leaks, vibrations, and other operational issues. Therefore, it is important to periodically check and tighten all bolts and fittings to ensure proper assembly and functioning of the evaporator.

• Monitoring performance:

  The performance of the evaporator should be monitored on a regular basis to ensure it is operating within the specified parameters. Key performance indicators, such as feed flow rate, steam consumption, and product concentration, should be tracked and compared to the expected values. If there are any deviations, the causes should be investigated and appropriate actions should be taken.

• Regular inspection of moving parts:

  Moving parts, such as pumps and fans, should be inspected on a regular basis to ensure they are in good condition and functioning properly. Bearings, belts, and other moving components should be lubricated as required to prevent friction and wear.

How to Choose Dairy Evaporator

A suitable evaporator is a core component in any dairy processing business. Here are some factors to consider when choosing a dairy evaporator:

• Capacity

  The capacity of the evaporator, which refers to the amount of milk processed in an hour, should be in line with the milk production requirements. For low production volumes, small-scale batch evaporators are suitable. On the other hand, large-scale continuous evaporators are ideal for high production volumes.

• Heat source

  The choice of heat source for the evaporator is also important. Various options are available, including electric heating, steam heating, and hot water heating. The heat source should be selected based on the availability of the heat source and the operational costs associated with the heat source.

• Energy efficiency

  Because of the high energy costs involved in the evaporation process, it is important to choose a dairy evaporator that is energy efficient. To achieve energy efficiency, one should look for features such as heat recovery systems that minimize heat losses and also double-effect or multi-effect evaporators that use the steam generated in previous evaporation stages.

• Product quality

  While the evaporator's design and features are primarily focused on increasing the concentration of milk solids, it is important to maintain the quality of the final product. The evaporator should be chosen in a way that minimizes the degradation of heat-sensitive components and also ensures the uniformity of the final product.

• Flexibility

  The chosen evaporator should be suitable for various dairy products. The evaporator should be flexible enough to allow adjustments to different production processes and also accommodate different milk compositions.

• Space and layout

  For the evaporator to be effective, it should be installed in a suitable location with adequate space for the dairy evaporator and all associated components. The dairy evaporator should also be suitable for the existing floor plan and the dairy processing plant's layout.

• Quality and safety standards

  The dairy evaporator should meet the required quality and safety standards. This is important because quality control and food safety are critical in dairy processing. The dairy evaporators should be compliant with the relevant quality and safety standards and also have appropriate certifications.

• Maintenance and serviceability

  The chosen evaporator should be easy to maintain. Accessibility for maintenance and cleaning activities should be considered. Additionally, the availability of technical support and spare parts from the evaporator manufacturer should be evaluated.

How to DIY and Replace Dairy Evaporator

Replacing a single-effect evaporator can be a complex process, as it involves working with specialized equipment and systems. Here are some general steps that are typically involved in replacing a single-effect evaporator:

• Preparation: Before starting the replacement process, proper planning and preparation are essential. This includes reviewing the system's technical documentation, identifying the specific evaporator to be replaced, and ensuring that a suitable replacement evaporator is available.
• System Isolation: The first step in the replacement process is to isolate the evaporator from the dairy processing system. This involves shutting down the associated services, such as steam supply, cooling water, and condensate return. Safety precautions should be taken to ensure that the system is depressurized and free of hazardous materials before proceeding.
• Piping and Connections: All piping and connections to and from the evaporator must be disconnected. This includes the feed inlet, concentrated outlet, steam supply, condensate return, and any other relevant connections. Proper labeling and documentation of the piping connections are essential for reassembly during the installation of the new evaporator.
• Support and Rigging: The old evaporator should be adequately supported and lifted using appropriate rigging equipment. Before removal, ensure that all safety considerations are met, and follow the relevant lifting and handling procedures.
• Removal: Once the evaporator is adequately supported and all connections are disconnected, it can be removed from its installation location. This may involve disassembling mounting hardware or support structures.
• Installation of the New Dairy Evaporator: The replacement evaporator should be installed in accordance with the manufacturer's instructions and relevant engineering practices. This includes securing the evaporator to its support structure, connecting all piping and services, and ensuring proper alignment and sealing of connections.
• System Reconnection: Once the new evaporator is installed, all associated services and piping systems should be reconnected. This includes steam supply, cooling water, condensate return, and any other relevant connections.
• System Commissioning: Before the replacement diary evaporator is put into operation, a thorough check is done to ensure that all systems, services, and functions are correctly installed and operational. This includes checking for leaks, verifying pressure and temperature settings, and ensuring proper control system integration.
• Documentation: Throughout the replacement process, all activities, changes, and relevant parameters should be documented. This includes system isolation, disassembly, installation, piping connections, and commissioning activities. Documentation is essential for traceability, compliance, and future reference.

Q&A

Q1: What are the common challenges faced when using dairy evaporators?

A1: Some challenges include fouling and scaling, which reduce heat transfer efficiency; maintaining product quality during concentration; ensuring the integrity of heat-sensitive components; and managing energy consumption.

Q2: How does one choose the right dairy evaporator for specific needs?

A2: Consider the type of dairy product to be concentrated, desired concentration levels, capacity requirements, energy efficiency preferences, budget constraints, and the availability of space for installation.

Q3: Are dairy evaporators noisy?

A3: While some noise is associated with the operation of dairy evaporators, particularly from pumps and fans, many modern evaporators are designed with noise reduction features. Proper installation and maintenance can also minimize noise levels.

Q4: How long does it take to evaporate water from dairy products using a dairy evaporator?

A4: The time required for evaporation depends on the capacity of the dairy evaporator, the rate of heat transfer, and the desired level of concentration. Generally, efficient evaporators can achieve significant concentration within hours.

Q5: Can a dairy evaporator be used for plant-based milks?

A5: Yes, dairy evaporators can be used for plant-based milks. However, specific settings and considerations may be required based on the composition and properties of the plant-based milk being processed.