Grit classifier

Types of Grit Classifier

Grit classifiers are an important part of wastewater treatment plants because they get rid of abrasive material like sand, gravel, and other organic and inorganic material. There are many types of grit classifiers, some of which are described below.

• Grit Screw Classifier: A typical classifier that separates waste material like organic and inorganic material using a water spiral system. The separation occurs through the velocity of water and the spiral speed. The organic material typically gets carried away with the water, while inorganic material gets carried away through the spiral. This type of classifier is very popular and is used extensively in treatment plants.
• Air Classifier: As the name suggests, this classifier uses air to separate out different types of materials. It makes use of the concept of gravity and drag forces. Heavier materials like sand settle down due to gravity, while lighter materials are pushed up by the drag force, which is caused due to air flowing at high velocity. An air classifier can be used alone or in conjunction with other classifiers to separate out various kinds of organic and inorganic material.
• Hydro Classifier: In this type of classifier, water is used to separate different types of minerals based on their sizes. It usually consists of a settling cone and a sand return pump. Smaller particles of material are pushed away through the water while larger particles settle down and are usually taken back through a return conveyor.
• Screw Classifier: A screw classifier is used to separate finer particles like sand from gravel, silt, coal, and other substances. It usually works in tandem with a dewatering screen, which helps in the separation of water from fine material. Like other classifiers, it depends on the principle of gravity to carry out the separation process.

Specification and maintenance of grit classifier

The specifications of a grit classifier vary depending on the type and intended application. Here are some of the key specifications of a typical grit classifier:

• Flow Rate

  This refers to the volume of wastewater that the classifier can process in a given period. Typically, the flow rate is indicated in gallons per minute (GPM) or cubic meters per hour (m3/h). The flow rate depends on the classifier size, motor power, and the wastewater's density and composition.

• Separation Size

  The separation size is the smallest particle the classifier can segregate from the wastewater. Usually, organic matters and sand are separated at 0.1mm, while silt is separated at 0.01mm. The separation sizes vary among classifiers, depending on the design and intended application.

• Motor Power

  Motor power determines the classifier's processing capacity and efficiency. The power is usually indicated in kilowatts (kW) or horsepower (HP). A higher motor power allows the classifier to process a larger volume of wastewater and handle more significant grit loads.

• Dimension

  The overall dimensions of a grit classifier include height, width, and length. The dimensions influence the classifier's capacity and the space requirements for installation.

• Clean Water Return

  In some cases, a grit classifier will have a provision for returning clean or partially clean water to the processing system. This feature helps reduce water consumption and enhance overall system efficiency.

Maintenance

Maintaining a grit classifier properly is crucial for optimal performance, longevity, and reliability. Here are some essential maintenance tips for grit lagers:

• Regular Inspection

  Users should make routine inspections of the grit classifier to identify any signs of damage, wear, or loose components. It is advisable to check the drive motor, classifier flights, bearings, gearbox, structure, and support assemblies. Early detection of potential issues helps to avoid costly repairs and prevent unplanned downtime.

• Lubrication

  Regular lubrication of moving parts is vital to maintaining the proper working operating condition of a grit classifier. Users should follow the manufacturer's instructions on the type and amount of lubricant to use. Focus on the bearings, gearboxes, and drives motor's bearings.

• Replace Worn Parts

  During routine inspections, if one notices any damaged or worn components, they should be replaced promptly. Classifier efficiency can be adversely affected by worn flights or bearings, thereby increasing the risk of equipment damage.

• Monitor Lubricant Condition

  Users should monitor the condition of the lubricant and replace it periodically as per the manufacturer's recommendations. If the lube looks contaminated or degraded, there may be a need for a more frequent replacement schedule or a change in the lubricant type.

Scenarios in using grit classifiers

Grit classifiers are mainly used in wastewater treatment facilities. However, other industries that generate settlable solid wastes apply these classifiers for the above purposes.

• Food and beverage facilities

  Food and beverage manufacturers will most likely find a grit classifier useful. Solid food particles and settlement gravel are food parts that often end up in wastewater. Hence, the classifier is used to separate them from the water, allowing the facility to use other treatment methods.

• Honey production

  Honey production plants also use grit classifiers to maintain the quality of honey products. When liquid honey is processed through the classifier, some crystallized grains are separated. These grains can be reintroduced into the honey production stage, improving the overall product.

• Meat processing

  Meat processing plants use grit classifiers in wastewater treatment. They separate non-dissolvable meat particles from wastewater. An airlift grit classifier is the most suitable classifier for this industry. It incorporates air-lift technology which increases microorganisms' contact with organic matter. This increases the treatment efficiency.

• Mining industry

  The mining industry is another industry that makes use of grit classifiers. They separate utility from other processes to conserve water. The settled grit is often pumped into the tailings facility for further treatment or disposal. Using grit classifiers allows the mining industry to conserve surface and groundwater resources.

• Construction industry

  The construction industry uses grit classifiers to improve the worksite's environmental footprint. They allow construction companies to recycle and reuse water for going through building projects. Also, they reduce the amount of sediment sent to landfills.

How to Choose Grit Classifier

When buying a grit classifier, a few things needs to be taken into consideration so as to ensure a seamless purchase experience and to be sure of getting the ideal classifier.

• Classifier's purpose and the kind of material to be worked on

  Before settling for a particular classifier, it is imperative to first find out the purpose of the classifier and the kind of material that will be worked on. To avoid any sort of mishap after purchase, it is important to assess if the classifier's purpose aligns with the project at hand. For instance, what kind of substances and materials will the classifier be handling? If the answers to these questions align to the capabilities of the grit classifier, then it is safe to go on and purchase the classifier.

• Circuitry of the classifier

  It is important to know the sort of classifier needed for the project at hand or the type of classifier that will work well with other mining equipment. Will a simple, straightforward classifier work well with the circuitry of other mining equipment? Or will a different kind of classifier be able to work better with other mining machinery? These are factors that should be considered before settling for any type of grit classifier.

• Capacity of the grit classifier

  While some small businesses can get by using classifiers with a lower or smaller capacity, large businesses will need to work with high-capacity classifiers in order to function properly. Depending on the company's needs, aim, and desires, a high-capacity classifier may be needed as a result. This is also true for the feed rate, which may vary depending on how the business is run and the material being worked with.

• Cost of the grit classifier

  When it comes to the cost of the classifier, there is no one-size-fits-all price because the price will vary depending on the specific type of classifier and its distinguishing features. While large companies may be able to procure high-quality classifiers at higher prices, small businesses may be limited to what they can afford based on their budget. Thus, this is a crucial factor to consider when making a purchase, as it will affect all aspects of the business.

Grit classifier Q&A

Q1 Are grit classifiers and separators the same thing?

A1. Not really. While they have a similar function, the classifier and separator act differently. The classifier is based on the shape, size, and specific gravity of particles. It controls and directs the flow of materials. On the other hand, the separator is based on the density of materials. It segregates through the whole classifier and separator machines.

Q2 Can grit classifiers handle different types of wastewater?

A2 Yes, the classifier can handle various types of wastewater. But the classifier design depends on specific characteristics of the wastewater. Otherwise, it may not work effectively.

Q3 Can grit classifiers be automated?

A3 Yes. Automation is possible in modern classifiers. Automation allows remote monitoring, automated controls, and automated grit removal.

Q4 Can classifiers be modified to enhance their efficiency?

A4 Yes. By adding components such as air flotation units or rotary drums, classifiers can be modified to improve efficiency.

Q5 Are classifiers energy-efficient?

A5 Yes, classifiers are usually energy efficient. They mainly use gravity to separate materials. Proper design enhances energy efficiency further.