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Category: indpro blog

Introduction to Rotary Airlock Valve

Posted on by Indpro

Introduction to Rotary Airlock Valve (RAV)

Pneumatic conveying systems play a vital role in efficiently transporting materials across various industries. A key player in these systems is the rotary airlock valve. If you’re unfamiliar with what rotary airlock valves are, how they operate, the various types available, and their typical applications, we’ve got you covered. This article aims to provide all the essential information about rotary airlock valves, commonly referred to as RAV, so you can gain a comprehensive understanding of their functionality and importance in material transport systems.


What is Rotary Airlock Valve?

Rotary airlocks go by various names like rotary locks, rotary feeders, or simply “airlocks.” Despite the different terms, their main job stays the same. They make it easy to move dry, free-flowing bulk solids—like powders, granules, pellets, nuggets, dust, and crystals—from a storage bin, storage silo, hopper, cyclone, or receiver through a pneumatic conveying system to the next step in the manufacturing process. These valves are essential for keeping material handling and pneumatic conveying systems efficient and reliable. They ensure a controlled and uninterrupted flow of bulk materials, prevent air leakage, and maintain system pressure.


How Does a Rotary Airlock Valve Work?

A rotary airlock is comprised of several key components, including a casted outer housing, a fabricated multi-vane rotor and shaft, endplates, a drive, shaft packing seals, and bearings.

Here’s a breakdown of its operation:

❖ Functionality:

  • When activated, the vanes of the rotary airlock rotate within the housing, resembling the movement of a revolving door. The primary objective is to facilitate the controlled movement of materials while preventing pressure loss, much like a revolving door manages the flow of people while preserving the indoor environment.

❖ Rotor Pocket:

  • The space between the rotating vanes forms the rotor pocket. This is where incoming material enters from the top opening and stays before being pushed out through the lower opening, continuing its journey through the pneumatic lines.

❖ Pressure Control:

  • The tight clearance between the vanes and housing minimizes pressure loss in the system. This is crucial, especially when dealing with varying pressures between bins, silos, hoppers, and the adjacent operation. Placing airlocks at the beginning of a pressure system or at the end of a vacuum system helps maintain optimal pressure conditions.


Types of Rotary Airlock Valves

Rotary airlock valves come in various types, each designed to suit specific applications and operational requirements. Here are some common types of rotary airlock valves:

Fall-Through Rotary Airlock Valve:​

  • In this type, the material drops through the valve and is discharged at the bottom.
  • It is suitable for gravity-fed applications where the material flows directly through the valve.

Blow-Through Rotary Airlock Valve:

  • Also known as “conveying” or “pneumatic” rotary valve.
  • Designed for use in pneumatic conveying systems.
  • The material is blown through the valve with the assistance of an air or gas stream.

Standard Duty Rotary Airlock Valve:

  • Commonly used for general-purpose applications where standard pressure differentials and material characteristics are present.

Heavy Duty Rotary Airlock Valve:

  • Designed for handling more abrasive or challenging materials.
  • Features robust construction to withstand wear and tear in demanding environments.

Quick-Clean Rotary Airlock Valve:

  • Designed for easy and quick disassembly and cleaning.
  • Suitable for applications where frequent cleaning and sanitation are necessary.

Dust Collector (Dust Disposal) Rotary Airlock Valve:

  • Especially used in dust collection systems.
  • Helps maintain a seal and prevent dust from escaping the collection system.


Seals used in Rotary Airlock Valve

Rotary airlock valves use various types of seals to maintain an airtight or dust-tight seal between different pressure zones in material handling and processing systems. Here are common types of seals used in rotary airlock valves:

Flexible Rubber Seals:

  • Soft rubber seals are commonly used for their flexibility and ability to conform to irregularities on the rotor and housing surfaces.
  • They provide an effective seal and are suitable for general-purpose applications.

Neoprene Seals:

  • Neoprene is a type of synthetic rubber known for its durability and resistance to abrasion, weathering, and chemicals.
  • Neoprene seals are suitable for applications where abrasion resistance is a concern.

Nitrile (Buna-N) Seals:

  • Nitrile rubber is widely used in seals due to its excellent oil resistance and flexibility.
  • Nitrile seals are suitable for applications where exposure to oils and greases is a consideration.

Polyurethane Seals:

  • Polyurethane offers good abrasion resistance and durability.
  • Polyurethane seals are suitable for applications involving abrasive materials and where extended wear life is required.

Metal-to-Metal Seals:

  • In some high-temperature or high-pressure applications, metal-to-metal seals may be used.
  • These seals are more robust and can withstand harsh operating conditions.

The selection of a specific seal depends on the specific requirements of the application, including the type of material being handled, the operating temperature and pressure, and the desired level of sealing effectiveness. Regular maintenance and monitoring of seals are important to ensure the continued reliability and performance of rotary airlock valves.


Types of Rotors used in Rotary Airlock Valve

There are several types of rotors used in rotary airlock valves, each designed for specific applications. The common types of rotors include:

Closed-End Rotor

A closed-end rotor has solid ends on both sides. It is suitable for handling non-abrasive materials and applications where a tight seal is essential to prevent air leakage between different pressure zones.

Open-End Rotor

An open-end rotor has one side open, allowing for easier material entry and discharge. It is commonly used in applications where material characteristics or system requirements permit some air leakage.

Dust-Collector Rotor

This type of rotor is designed with large pockets to collect and discharge fine dust or powders. It helps prevent material build-up and reduces the risk of rotor jamming, making it suitable for applications with dusty materials.

Shallow-Pocket Rotor:

Shallow-pocket rotors are designed with smaller pocket depths. They are often used for applications involving sticky or tacky materials to prevent material build-up within the pockets.

Adjustable-Tip Rotor:

Adjustable-tip rotors allow the rotor tips to be adjusted to maintain the proper clearance between the rotor and the housing. This feature is useful for fine-tuning the valve’s performance and addressing wear over time.

Rigid Pocket Rotor

Rigid pocket rotors have reinforced pockets, making them suitable for handling abrasive materials. They provide increased durability and resistance to wear.


Materials used for manufacturing Rotary Airlock Valve

Rotary airlock valves are crucial components in pneumatic conveying systems, and their construction materials are chosen based on factors such as the type of material being handled, the system’s operating conditions, and considerations for wear resistance. Common materials used for manufacturing rotary airlock valves include:

Carbon Steel:

Carbon steel is often used for the construction of rotary airlock valve components, including the endplates and rotor. It offers strength and durability in various operating environments.

Cast Iron:

Cast iron is a common material for rotary airlock valve housings and endplates. It provides good strength and wear resistance. Gray iron and ductile iron are variations of cast iron used in different applications.

Stainless Steel:

Stainless steel is chosen for applications where corrosion resistance is critical. Types such as 304 and 316 stainless steel are commonly used to prevent rust and corrosion, making them suitable for handling corrosive materials or operating in harsh environments.

Aluminum:

Aluminum is chosen for applications where weight is a significant consideration. It is lighter than steel, making it suitable for certain industries or applications with specific requirements.

Hardened Steel or Tool Steel:

Hardened or tool steel may be used for rotors, especially in applications where abrasion resistance is crucial. Hardened steel helps extend the life of the rotor in handling abrasive materials.

Ceramic Coatings:

Some rotary airlock valves may have ceramic coatings or inserts to enhance wear resistance, particularly when handling abrasive materials. Ceramic materials provide excellent resistance to abrasion.

Specialized Coatings:

Various specialized coatings, such as tungsten carbide, may be applied to critical wear areas to improve durability and extend the life of the rotary airlock valve in challenging conditions.

Polymer and Composite Materials:​

In certain applications, polymer or composite materials may be used for specific components to provide chemical resistance or reduce wear. This can include polymer housings or coatings.


Factors to be considered for selection of Rotary Airlock Valve

Material to be conveyed

When choosing a rotary airlock, consider the material characteristics such as abrasiveness, moisture content, and particle size. Selection factors include using hard-faced components for abrasives and ensuring a tight seal for moist materials to prevent air entry and drying. The rotary airlock should match the specific requirements of the material and its flow characteristics.

Flow Rate

For effective pneumatic conveying systems, choose a rotary airlock that matches the material’s flow rate. Avoid bottlenecks by ensuring the rotor’s size and speed align with the flow rate. An appropriately sized rotary airlock enhances energy efficiency and reduces maintenance costs.

Pressure Drop

When selecting a rotary airlock, be mindful of pressure drop—the difference between inlet and outlet pressures. High pressure drop reduces system efficiency and increases energy costs. To minimize this, choose a rotary airlock with a tight seal and a rotor correctly sized for the flow rate.

Type of Pneumatic Conveying System

Selecting the right rotary airlock depends on the type of pneumatic conveying system. Dilute phase systems benefit from flow-through rotary airlocks (drop-through), suitable for materials like grain, coffee beans, polymer granules, etc. Materials like flour, cocoa powder, chemical powders work well with blow-through rotary airlocks. Matching the rotary airlock to the conveying system ensures optimal performance.

Maintenance and Repair

Go for designs that provide convenient access to the rotor and vanes. Look for rotary airlocks with replaceable parts to minimize downtime and lower maintenance costs.

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What is a Blower

Posted on by Indpro

What is a Blower?

Pneumatic conveying systems play a crucial role in moving bulk materials such as powder, pellets, granules, grains, spices, etc., through enclosed pipelines using gas, commonly air or nitrogen. These systems, having applications across various industries, utilize gas pressure differential and flow to transport granular or powder materials. This article delves into the diverse blowers used in pneumatic conveying systems, exploring their working principles covering selection criteria.


What is a Blower?

A blower is a mechanical device that generates a flow of air or gas, typically for the purpose of moving or circulating air in various applications. Blowers are commonly used in HVAC (Heating, Ventilation, and Air Conditioning) systems, pneumatic conveying systems, water or effluent treatment, industrial processes, and various other settings where the movement of air or gas is required. They come in different types and sizes to suit specific applications.


Blower Types and Working Principles:

Blowers come in various types and subtypes, each designed for specific applications and operating conditions. The working principle of a blower involves converting mechanical energy, usually provided by an electric motor or engine, into kinetic energy and then into pressure energy. The type of blower, whether centrifugal, axial, positive displacement, or regenerative, determines the specific mechanism by which this conversion occurs.

1. Centrifugal Blower :

  • Also known as radial fans or centrifugal fans
  • These blowers use a rotating impeller to create a centrifugal force that accelerates the air or gas outward from the center of the device
  • Centrifugal blowers are often used in HVAC systems, industrial ventilation, and air pollution control
  • The types include forward-curved centrifugal blowers, backward-curved centrifugal blowers, radial blowers, compact centrifugal blowers, high temperature centrifugal blowers, corrosion resistant centrifugal blowers, high pressure blowers, multistage centrifugal blower

Working Principle :

  • Impeller Rotation: The blower has an impeller with blades that rotates within a casing.
  • Air Intake: Air or gas enters the blower through an inlet.
  • Centrifugal Force: The rotating impeller imparts centrifugal force to the incoming air, causing it to move radially outward.
  • Diffusion: The outward-moving air then enters a diffuser, which slows down the air and converts kinetic energy into pressure energy.
  • Air Discharge: The air is discharged from the blower at an increased pressure and velocity.

2. Axial Blower :

  • Also known as axial fans
  • Axial blowers move air parallel to the axis of the impeller
  • They are commonly used for applications such as cooling electronic equipment, providing ventilation in confined spaces, and cooling industrial processes

Working Principle :

  • Impeller Rotation: Axial blowers have an impeller that rotates around an axis parallel to the direction of the airflow.
  • Air Intake: Air enters axially, parallel to the axis of rotation.
  • Axial Flow: The impeller propels the air in a straight-through direction.
  • Air Discharge: The air exits the blower in the same axial direction.

3. Positive Displacement Blowers :

  • Also known as rotary lobe blowers or rotary piston blowers.
  • These blowers utilize positive displacement to move air or gas.
  • Positive displacement blowers are often used in applications such as pneumatic conveying, wastewater treatment, and aeration in water treatment plants.

Working Principle :

  • Lobe or Screw Movement: Positive displacement blowers use rotating lobes or screws to trap and move a fixed volume of air or gas with each revolution.
  • Air Compression: As the lobes or screws rotate, they create pockets of air, compressing and displacing it through the blower.

4. Regenerative Blowers :

  • Also known as side channel or ring channel blowers.
  • These blowers use the regenerative principle to create air flow.
  • They are often used in applications requiring low flow rates and moderate pressure, such as vacuum packaging, vacuum lifting and pneumatic conveying.
  • The types include single stage regenerative blowers, multistage regenerative blowers

Working Principle :

  • Impeller Spin: Regenerative blowers have an impeller with multiple blades that spin rapidly.
  • Regenerative Action: The spinning impeller generates airflow by pushing air outward to the housing walls, creating a regenerative effect.
  • Continuous Movement: The regenerative process contributes to the continuous movement of air.

5. Multistage Blowers :

  • Also known as side channel or ring channel blowers.
  • These blowers use the regenerative principle to create air flow.
  • They are often used in applications requiring low flow rates and moderate pressure, such as vacuum packaging, vacuum lifting and pneumatic conveying.
  • The types include single stage regenerative blowers, multistage regenerative blowers


Selection criteria for Blower

Selecting the right blower for a specific application involves considering various factors to ensure optimal performance and efficiency. Here are key criteria for blower selection:

Airflow Requirements:​

  • Determine the required volume of air (in cubic feet per minute or cubic meters per second) for the application.
  • Consider the variations in airflow demand and whether the blower needs to operate at a constant or variable speed.
  • Key parameters considered for calculating airflow requirements are conveying capacity, distance & number of bends in conveying line.

Pressure Requirements:​

  • Identify the system’s pressure needs, usually expressed in mm of water column (mmWC) or pascals.
  • Consider both static pressure (resistance to flow) and dynamic pressure (velocity of the air).

Temperature Considerations:

  • Evaluate the temperature of the air or gas being handled by the blower.
  • Choose a blower that can operate effectively within the specified temperature range.

Altitude & Atmospheric Conditions:

  • Account for the altitude at which the blower will operate, as this affects the air density.
  • Consider the humidity and other atmospheric conditions that might impact blower performance.

Application Type:

  • Different applications like dilute phase/dense phase pneumatic conveying, etc. require specific types of blowers (e.g., centrifugal, axial, positive displacement).
  • Consider whether the blower is needed for ventilation, material handling, pneumatic conveying, aeration, or other purposes.

Efficiency & Energy Consumption:

  • Evaluate the blower’s efficiency to ensure it meets energy efficiency standards.
  • Consider the total cost of ownership, including energy consumption and maintenance costs.
  • Choose a blower with a capacity, matching usual requirements, add a factor of safety for demand variations, and avoid overcapacity to optimize energy consumption in pneumatic conveying systems.

Operating Speed & Control:

  • Determine the required operating speed and consider if variable speed control is necessary for the application.
  • Variable speed control can optimize energy efficiency by matching the blower’s speed to the actual demand.

Noise Level:

  • Assess the noise level produced by the blower and ensure it complies with the acceptable noise standards for the application.
  • General criteria for acceptance of noise level: Noise Level < 85dB
  • Silencers, Acoustic Covers are used to reduce noise level.

Space Constraints:

  • Consider the available space for installing the blower.
  • Choose a blower that fits within the available footprint while allowing for proper ventilation and maintenance access.

Material Compatibility:

  • Verify that the blower materials are compatible with the handled air or gas, especially if it contains corrosive or abrasive elements.

Reliability & Maintenance:

  • Evaluate the blower’s reliability and ease of maintenance.
  • Choose a blower with a track record of reliability and one that is easy to access for routine maintenance tasks.

Budgetary Constraints:

  • Consider budget constraints and choose a blower that offers the best balance of performance and cost-effectiveness.

By carefully considering these criteria, engineers and system designers can select a blower that meets the specific needs of the application, ensuring efficient and reliable operation over time. For pneumatic conveying systems, the design criteria are crucial to the performance of the system, as the parameters are directly proportional to the right selection. Get in touch with subject matter experts at Indpro to know more about these selection criteria.

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Different Prime Movers used in Pneumatic Conveying of Materials

Posted on by Indpro

Different Prime Movers used in
Pneumatic Conveying of Materials

Pneumatic conveying systems facilitate the movement of bulk materials like powder, pellets, granules grains, spices, etc. through enclosed pipelines using gas, typically air or nitrogen. Widely employed in various industries, these systems leverage gas pressure differential and flow to transport granular or powder materials. This article delves into the diverse prime movers used in pneumatic conveying systems, exploring their working principles.


What is Prime Mover?​​

Prime mover is a vital part of pneumatic conveying system. These prime movers serve as the driving force to propel gas within the pipelines in pneumatic conveying systems. The key types include compressors, blowers, and vacuum pumps.

Types of Prime Mover -


1. Vacuum pump: Function, Working principle & Types​

Function of Vacuum Pump – A vacuum pump is a device designed to eliminate gas molecules or air particles from a sealed volume, creating a pressure difference and generating a partial vacuum.

Working Principle & Types of Vacuum Pumps

The fundamental principles of vacuum pumping can be broadly classified into two main categories: gas transfer and entrapment. Gas transfer itself can be subdivided into two distinct methods known as positive displacement and momentum transfer. Understanding the three types of flow: viscous, transitional, and molecular—provides a deeper insight into the concepts of vacuum pumps.

Viscous/continuous flow:

Viscous flow takes place at high pressures to medium vacuum levels. In this scenario, the gas is dense enough for gas molecules to collide with each other. The mean free path, which represents the average distance a gas molecule travels, is shorter than the dimensions of the chamber. As the vacuum level increases, gas molecules are more likely to collide with the chamber walls than with other gas molecules.

Transitional flow:

Transitional flow occurs when viscous flow begins to transition into molecular flow. This shift happens as the mean free path of gas molecules becomes comparable to or exceeds the dimensions of the chamber.

Molecular flow:

Molecular flow is defined by the random motion of gases, where the mean free path of gas molecules is notably greater than the dimensions of the chamber. In this scenario, collisions between gas molecules are infrequent, and their movement is primarily determined by the chamber’s geometry. Positive displacement pumps can mechanically pump fluids that are flowing under viscous conditions. However, when the gas cannot be evacuated by pressure difference, molecular flow is reached When fluids transition into molecular flow, positive displacement pumps become inadequate. In such situations, additional pumping systems like momentum transfer or entrapment pumps are employed to maintain the required vacuum levels.  In most high vacuum systems, two pumps are typically employed together. Positive displacement pumps alone prove insufficient for achieving higher vacuum levels. Momentum transfer pumps run the risk of stalling when the system operates under viscous flow conditions. Entrapment pumps may require frequent regeneration or emptying, particularly when dealing with high gas volumes, especially in situations involving viscous flow.

i. Positive Displacement Vacuum Pumps:

Positive displacement vacuum pumps function by alternately expanding and contracting a sealed chamber, with the flow of fluid regulated by one-way valves. The process begins with the expansion of a sealed chamber, creating a vacuum that draws fluid through an intake valve. As the chamber reaches maximum expansion, the intake valve closes, and the exhaust valve opens. As the chamber compresses or contracts, the fluid is expelled. This cycle repeats multiple times per second, generating a pulsating flow. There are two main types of positive displacement pumps – Reciprocating (Piston Pump, Plunger Pump, Diaphragm Pump) & Rotary (Vane Pump, Liquid Ring Pump, Rotary Piston Pump, Screw Pump, Gear Pump, Lobe Pump)

ii. Momentum Transfer Vacuum Pumps:

Momentum transfer pumps operate by inducing the movement of gas or liquid molecules through the transfer of kinetic energy. This occurs at the molecular flow level, in contrast to the viscous or continuous flow observed in positive displacement pumps. Its types include Turbomolecular Pump & Diffusion Pump.

iii. Entrapment Vacuum Pumps:

Entrapment vacuum pumps utilize various physical and chemical phenomena to capture gas molecules. These pumps operate in high vacuum regimes without causing oil contamination. Its types include Cryogenic pump, Sorption Pump, Sputter Ion Pump, Centrifugal Pumps.


2. Blower: Function, Working principle & Types

  • Function of Blower : Function of blower is to move air and gas at low to high pressure to perform a specific function. Blowers play a versatile role in numerous industries, serving various applications such as cooling, conveying, ventilating, exhausting, and more.
  • Working Principle of Blower: An air blower utilizes a rotating impeller or rotor to generate a vacuum, drawing air into the blower. As the air enters the center of the impeller, it is separated by the rotating blades. The centrifugal force increases both the speed and volume of the air stream within the housing

Types of Blowers -

i. Positive Displacement Blowers:

A positive displacement blower operates to maintain a consistent flow and speed regardless of changes in pressure. This characteristic makes it well-suited for moving neutral and air gases. The blower effectively removes gas through the decreasing section, trapping and releasing air in a cyclical manner. There are two distinct types available – the Rotary Lobe Blower and the Helical Screw Blower.

ii. Centrifugal Blowers:

A centrifugal blower is effective in controlling air pollution and facilitating gas transportation. This type of blower is commonly employed for ventilation purposes, operating by altering the direction of airflow with a 90-degree turn. Continuous gas transfer is achieved as the gas passes through the centrifugal blower, increasing kinetic energy. Equipped with rotating impellers, these blowers are suitable for applications requiring variable flow with high pressure.

iii. Multistage Centrifugal Blowers:

Multistage centrifugal blowers are a specific type within the centrifugal blower category. These blowers utilize multiple stages to rotate the machine and increase air pressure. Equipped with an electric motor that provides high-pressure tolerance, they are suitable for applications with high flow rates. Multistage centrifugal blowers find utility in various sectors, such as the wastewater treatment industry, powering artificial lungs, and boosting landfill gas.

iv. High-Speed Blowers:

High-speed blowers are designed to provide both high pressure and high flow, making them versatile for various applications. These blowers typically feature impellers on each side, directly coupled to a motor. The ability to connect them to a permanent magnet motor with a variable frequency drive allows for efficient control and adjustment based on specific operational needs.

v. Regenerative Blowers:

A regenerative blower is characterized by oil-free components, making maintenance relatively easy. Ideal for applications requiring low pressure, these blowers operate by displacing air molecules and creating pressure through non-positive displacement, forcing the air to move.


3. Compressor: Function, Working principle & Types

  • Function of Compressor: A compressor is a device designed to compress air or other gases, elevating their pressure beyond atmospheric levels. It takes in air from the atmosphere and increases its pressure through compression.

  • Working principle & types of compressors: To explain the working principle of air compressors, it’s crucial to differentiate between various types of compressors: reciprocating (piston) and rotary (screw) compressors.

i. Reciprocating Compressor:

In a reciprocating compressor, air compression occurs through cylinders, pistons, and cranks. These components, driven by an electric or combustion engine, draw air into the cylinder and compress it using pistons. The compression process may consist of one or multiple stages until the desired operational pressure is reached. The compressed air then passes through a cooler into the air tank. These are used by many industries which includes Chemical, Petrochemical, Oil & Gas, Refrigeration, etc. Reciprocating compressors come in various types, including Single Acting, Double Acting, Single Stage, and Double Stage.

ii. Rotary Compressor:

Rotary compressors operate differently from reciprocating compressors. Instead of using pistons and cylinders for compression, rotary compressors employ rotating screws to initiate compression. Air is forced between two rotating screw elements, resulting in compressed air. As the compression generates heat, a cooling liquid, often oil, is injected into the compression chamber. This cooling liquid circulates between the cooling chamber, liquid tanks, and coolers to maintain the operating temperature around 80°CThese are utilized in various industries, including the food sector. Packaging sector, Automotive sector, etc. The types rotary compressors include Rotary Screw compressor which is most widely used, Scroll Type compressors, Vane Type compressors & Lobe Type compressors.


Selecting the Right Prime Mover for Pneumatic Conveying System

Choosing the appropriate prime mover for your specific system is of greatest importance in optimizing operational efficiency and lifespan of equipment. Below are some guidelines for selection of right prime mover for pneumatic conveying system:

Fan

It is used when working with dilute phase pneumatic conveying systems (both pressure as well as vacuum based) with low solids-to-air ratio

Lobe Blower

It is used when working with dilute phase pneumatic conveying system (both pressure as well as vacuum based) with high solids to air ratio

Vacuum Pump

It is used when working with dense phase vacuum type pneumatic conveying system

Compressor

It is used when working with dense phase pressure type pneumatic conveying system

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Battery Recycling Process of Lead-Acid and Lithium-Ion

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Battery Recycling Process

In contemporary times, numerous types of equipment operate on either batteries or gas. The shared characteristic between these two elements is their finite usage; once depleted, the customary practice involves refilling gas or disposing of used batteries and acquiring replacements.

Nevertheless, discarding batteries can contribute significantly to environmental waste, given their widespread use and the presence of harmful materials within them. Consequently, disposing of batteries may not be a prudent course of action. An alternative to discarding used batteries is recycling them.

In contrast to materials like plastic and paper, battery recycling may not be as widely understood. Therefore, we’ve compiled this article to provide you with a fundamental understanding of battery recycling.

Battery Recycling Process Banner

What is battery recycling?

Battery recycling is a vital practice that involves the reuse and reprocessing of batteries, with the primary objective of reducing the volume of batteries being discarded as material waste. Batteries contain a range of hazardous chemicals and heavy metals, and their improper disposal has raised significant environmental concerns, including the contamination of water and soil. Therefore, battery recycling is essential to align with environmental and health regulations, as well as to reap associated benefits.

Batteries, by their nature, have a finite lifespan. Eventually, they either become damaged or cease to function. This is precisely when battery recycling becomes crucial.

How the batteries are recycled?

It is important to understand the process of recycling batteries. There are various types of technologies and material used to produce batteries which must be considered before delving into the recycling process.

Batteries exhibit variations based on their constituent components, which encompass lead-acid, lithium-ion (Li-ion), nickel-metal hydride (Ni-MH), nickel-cadmium (Ni-Cd), lithium-ion polymer, nickel-zinc, and alkaline materials. Manufacturers utilize these components to create various types of batteries, each potentially differing in terms of their intended applications, power output, and the specific recycling processes they entail.


Recycling process of Lead-Acid Batteries​

Lead-acid batteries hold the distinction of being the earliest form of rechargeable batteries worldwide. They are composed of a combination of lead and sulfuric acid.

Recycling process of Lead-Acid Batteries

1. Collection:

The initial step in the battery recycling process entails the collection of discarded lead batteries from various disposal points.

2. Crushing :

Following the collection phase, the subsequent step in the recycling of lead batteries involves their disassembly. Recycling facilities employ mills or industrial crushers to crush the batteries into smaller fragments during this phase.

After crushing, the material is stored in small bags, jumbo bags, or in some permanent storage unit and then it is transferred to the sorting station. Automation solutions can include bag filling machine, big bag unloading station, bag dump station, and pneumatic conveying system for the crushed material to be conveyed to multiple storage silos for storing, and then as per the requirement, it can extract from those silos.

3. Sorting:

In this phase, the lead-acid battery components are meticulously separated. Recyclers distinguish and segregate the plastic and paper components from the lead and metal parts of the battery. The lead and heavy metals extracted from the battery then undergo subsequent processing for recycling.

4. Sieving:

Within this process, recyclers carry out the removal of thermoplastic components present in the battery. Following this, they utilize a sieving process to extract the liquid contents from the battery, leaving behind the dry lead components. Subsequently, the lead and heavy metals proceed to the final stage of the recycling process.

After the sieving operation, dry lead which is in powder form is passed through a cyclone separator to discharge the powder material into the collection unit which is further connected to the extraction process. Automation systems include a cyclone separator & dust collection system which will smoothly carry out the operation for feeding material into the collection unit and the generated dust shall be transferred to the centralized dust collection unit.

The scrap plastic materials from batteries are collected in the warehouse in a loose form and then they get transferred to the washing lines using a pneumatic conveying system for the extraction process. These reprocessed thermoplastics are used to create battery casings and other new plastic products by manufacturers.

5. Extraction:

In the last phase of lead-acid battery recycling, recyclers extract the lead powder and heavy metal components from the remaining battery remnants.

This procedure can be executed in two distinct manners:

Pyrometallurgy based – Pyrometallurgy is a metallurgical process that relies on heat for the extraction and purification of metals. It involves roasting, smelting and refining.

Hydrometallurgy based – Hydrometallurgy is the method employed for extracting metals from ore. It involves leaching, solution-based concentration, and purification & metal recovery.

Both hydrometallurgy and pyrometallurgy ultimately yield molten lead as the end product. Recyclers then shape this molten lead and deliver it to manufacturers to be used in the production of new batteries.


Recycling process of Alkaline Zinc Air /Zinc Carbon Batteries

Recycling alkaline batteries involves a mechanical dismantling process. Similar to other types of batteries, the initial step is the collection of used alkaline batteries. Subsequently, the batteries are sorted after being dismantled.

Following the disassembly of alkaline batteries, recyclers extract three key components for additional processing: steel components, plastic and paper components, and zinc and manganese components.

Subsequently, these materials are packed & sent to recycling facilities, where manufacturers recover them for the production of new products.


Recycling process of Lithium Ion, Nickel Metal Hydride, Nickel-Cadmium Batteries

Lithium-ion (Li-ion) batteries, commonly employed in cars and electronic devices, are rechargeable. Nickel-based batteries, another rechargeable type, find use in portable devices such as cameras and in home or office UPS devices.

Both lithium-ion (Li-ion) and nickel-based batteries share similarities with lead-acid batteries in the final stages of recycling. Here is a detailed step-by-step process for recycling lithium and nickel batteries.

Recycling process of Lithium Ion

Step 1: Collection

Recyclers collect used lithium and nickel batteries from collection points or various other locations.

Step 2: Sorting

During this phase, recyclers carefully separate the plastic materials within the battery from the metal components. Both of these materials can be effectively repurposed in the creation of new products.

Step 3: Shredding

The sorted batteries are passed through a shredder which breaks the battery into coarse particles. After shredding, the coarse material is then transferred to the crushing station using a conveying system.

Step 5: Smelting

In this phase, the components of lithium-ion and nickel-based batteries undergo a process known as High-Temperature Metal Reclamation. During this process, metals present in the batteries, such as nickel, manganese, chromium, and iron, are extracted, conveyed via line to packaging station & and sent to manufacture new products.

Step 4: Crushing

The different types of shredded materials are then crushed into fine particles by using a mill or crusher, and collected material gets conveyed using a conveying system to the smelting process.


Recycling process of Mercury Batteries​

Mercury batteries, after collection, undergo recycling through liquid and heat extraction methods. These batteries contain highly toxic heavy metals, necessitating their processing in carefully controlled extraction environments to minimize environmental and health risks.

The mercury obtained through these extraction processes serves as a valuable resource for manufacturing new mercury batteries, measuring instruments, and components for fluorescent lights. Additionally, manufacturers can repurpose the plastic and other materials obtained from the batteries to create various new products.

Benefits of battery recycling

  • Conservation of Non-Renewable Resources
  • Prevents pollution
  • Minimizes solid waste deposited in landfills
  • Energy saving

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Biscuit manufacturing process

Posted on by Indpro

Biscuit manufacturing process

The term “biscuit” finds its origins in the Latin phrase “bis cotus,” translating to “twice baked.” This culinary concept traces its roots back to the time of the Romans. Nonetheless, the biscuits we recognize today started to evolve during the era of the Middle Ages.

In the 1800s, spurred by the Industrial Revolution, the era of mass-producing cakes, biscuits, and jellies was ushered in. It was during this transformative period that numerous novel biscuit varieties came into existence.

On the global stage, India holds the distinction of being the third-largest biscuit producer, trailing behind only the United States and China. This status is driven by factors such as increased consumer income, a preference for premium biscuits, expanded production capacity, growing health awareness, product innovation, and appealing packaging.

As demand continues to surge, it becomes imperative for production to keep pace accordingly. To enhance and refine the biscuit production process, the implementation of plant automation is crucial. Tasks such as raw material handling, bulk storage, cleaning & sieving, mixing, batch preparation, and packaging are automated within biscuit processing. This automation culminates in the production of a top-tier, high-quality finished product.

Indpro specializes in automated bulk material handling systems, catering to the needs of biscuit manufacturers. Our solutions seamlessly manage raw materials handling, starting with the efficient transfer of materials from bulk containers or bulkers into various storage silos.

Both external and internal silos play vital roles in the production process, serving as indispensable components. The automation solutions include handling of 25 to 50-kg bags and even upto 1000 kg jumbo bags which ensure a smooth transition from handling powders inside the bags into the production line using utmost automation while eliminating dusting & maintaining expected hygiene standards.

Additionally, precise weighing systems for ingredients and minor components ensure accuracy in the production process. This comprehensive suite of offerings plays a vital role in optimizing biscuit manufacturing and other related industries, enhancing efficiency, and maintaining product quality.

Materials used for Biscuit Manufacturing are –

Wheat Flour for biscuit

Flour

Typically, wheat flour is the primary ingredient in biscuit manufacturing, although other flours like rice or corn may also be used.

sugar-for-biscuit

Sugar

Sugar provides sweetness and aids in browning.

Leavening Agents

Baking powder and/or baking soda, play a crucial role in causing biscuits to rise, resulting in their characteristic light and fluffy texture.

milk-for-biscuit

Liquid

Water or milk is added to bind the ingredients together.

chocolate-chips-for-biscuit

Flavorings

Flavorings like vanilla, chocolate chips, nuts, and spices are often added for taste.

butter-for-biscuit

Fats

Fats such as butter, margarine, or vegetable oils contribute to the texture and flavor of biscuits.

Challenges faced by the Biscuit Manufacturing Industry:

Mixing of Foreign Matter:

In the biscuit production process and throughout the raw material supply chain, the inadvertent inclusion of foreign objects like operators’ hair, plastic bristles, packaging materials, sealing threads, needles, and the like, poses a risk of compromising product quality and safety.

Excessive sulfur dioxide:

Excess sulfur dioxide content found in biscuits primarily stems from the breakdown of the dough modifier, sodium metabisulfite. In the biscuit manufacturing process, food companies may occasionally incorporate excessive quantities of sodium metabisulfite to enhance dough extensibility and plasticity, inadvertently leading to elevated sulfur dioxide levels.

Misuse of additives:

Due to fierce market competition, some biscuit manufacturers use cost-cutting additives to improve taste. These additives, when misused, can be harmful to consumers, often going unnoticed.

Cost Escalation

The biscuit industry’s growth is currently hindered by significant inflation in raw material and packaging costs. The cost escalation is impacting to control the final product manufacturing cost ultimately seeing hike in prices.

Steps followed by the current industries for manufacturing biscuits:

Step 1: Raw material receipt:

In the realm of ingredient management, a well-structured warehouse is the hub for gathering and storing various ingredients, packaged in diverse formats such as bags (25 to 50 kg), jumbo bags (500 to 1000 kg), drums (50 kg), and even bulker shipments. Preserving ingredient quality during transportation is critical, requiring a well-orchestrated supply chain.

Automation solutions include Raw Material Handling solutions, including a Manual Bag Dump Station, Bag Lifter & Tilter, Jumbo Bag Unloading System, Bulker Unloading System, Automatic Bag Slitting Machine, Storage Silos, and Pneumatic Conveying System. These solutions streamline ingredient logistics, ensuring efficient and reliable transport, and supporting various industries’ smooth operations.

Step 2: Pre-Mixing:

In the biscuit-making process, the dry ingredients, including wheat flour, sugar, leavening agents, Skimmed Milk Powder, and Malt extract, along with fats, are first combined and mixed until they resemble coarse crumbs.

Here is where automation systems play a crucial role, offering a range of specialized equipment and systems to facilitate this mixing process. These solutions include Specialized Blenders and Weighing & Batching Systems. These solutions ensure a seamless and efficient transition from the initial mixing of dry ingredients to the subsequent stages of biscuit production, contributing to the consistency and quality of the final product.

Step 3: Mixing:

As the biscuit-making process advances, the dough begins to take shape, and this is where the liquid ingredients, along with sugar, are carefully introduced to achieve the desired consistency in the mixture. For biscuits like short dough varieties, a lighter mixing is employed to maintain crispiness and fluffiness.

Step 4: Moulding:

During this crucial stage, the biscuit’s shape is determined, with options ranging from round to various intricate designs. This process divides the dough into desired portions and involves a knife, a forcing roller, and precise control in multiple directions.

Step 5: Baking:

Biscuits are baked in ovens at a specific temperature and time, which varies depending on the type of biscuit being produced. The heat causes the leavening agents to create gas, making the biscuits rise and become crispy.

After baking, a batch or batches of biscuits are checked for their texture, color, cooking level, and height. A meticulous inspection process ensures that they meet the required specifications.

Step 6: Cooling:

After baking, biscuits are cooled on wire racks to room temperature. The biscuits pass through a cooling tunnel, where they are cooled to the desired hardness, preparing them for packaging.

Step 7: Packing:

Once cooled, biscuits are packaged in various ways, including boxes, bags, or individual wrappers. Packaging often includes branding and labeling for marketing purposes.

Step 8: Quality Control:

Biscuit manufacturers implement strict quality control measures to ensure consistency in taste, texture, and appearance. Samples are regularly tested for taste, texture, and shelf life.

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