Optic cable blowing is the process of inserting an optical fiber cable into a duct by combining a mechanical pushing force and a high-speed air flow into micro ducts, pipes and tube packages.  

The compressor used for fiber optic cable blowing generates high and stable compressed air pressure, which allows the cable inside the duct to remain floating. This process reduces friction between the outer cable surface and inner duct wall. It also allows air pressure to be pushed through long distances and complicated pipe routes using a blower. 

The role of the compressor is therefore critical in the efficient and reliable installation of fiber optic cables. It allows quick and easy blowing while reducing the cost and time required. However, to be able to use the compressor to its full potential, it is necessary to choose the right model to match the blower.  

It is vital to select the appropriate model to complement the blower. One must ensure that the compressor is correctly sized for the project and can deliver 10 to 14 bar air pressure. The compressed air will then be cooled close to ambient temperature with aftercooler option.  

ELGi’s portable air compressors play a vital role in cable blowing by providing reliable support to our customers. 

Tunnel development is majorly driven by investments in the metro rail, railway, roads and highways, hydropower, underground crude oil storage and water & sewerage segments. And with the increasing investments in the sector, the size of tunnelling projects has also witnessed a substantial increase! 

Etched in concrete 

Concrete spraying is one of the most demanding application tasks in underground mining and tunnel construction. It has become the industry standard for initial and final support in underground construction, as it provides a safe working environment for operators and significantly reduces material and time-related costs onsite. 

Compressed air for concrete spraying:

Basic requirements for a high-quality application of sprayed concrete include surface preparation, continuous concrete flow, exact dosing of the accelerator, and correct amount of compressed air! 

Now let’s look into the key elements that play an important role in compressed air systems for construction:  

1. To reduce the rebound to a minimum, the nozzle must point perpendicular to the surface 

2. To achieve a good compaction of the concrete on the surface, the stand-off distance between the nozzle and surface must be kept between 1-2 m.

3. The spraying process should always take place from bottom to top, allowing especially when spraying thick layers, the previous sprayed concrete to support the next layer, and to prevent spraying of areas that received rebound.

Role of compressed air? 

Compressed air is utilized to accelerate the concrete to a speed suitable for positioning the nozzle from the rock surface. Special chemicals known as accelerators are frequently added to speed up the hardening of the sprayed concrete.  

ELGi’s electric compressor PG 55ES with 325cfm and 9.5bar working pressure plays a vital role in the concrete spraying application by running as an onboard compressor option to one of leading concrete spraying equipment manufacturers in the world. 

With India’s chemical industry expected to grow at a CAGR of 9.3% and reach US$ 304 billion by 2025, it becomes a highly relevant economic domain. It is imperative to equip it with essential infrastructures and amenities.  One of these elements is clean compressed air. 

Why is clean compressed air so important in the chemical industry? 

Both chemical production processes and petrochemical applications must meet very strict safety standards. Product purity and strict quality control must be maintained to ensure that manufacturers provide customers with the highest quality chemicals. Toxic, explosive, corrosive, and changeable substances are used in the chemical production process. Therefore, compressed air must be dry and free from contaminants like dust/oil residues to avoid reacting with these substances.  

In most applications, compressed air may be exposed to the product. The presence of contaminants such as oil in compressed air sources can cause costly product spoilage and production losses. Contaminants such as oil and dust particles in the compressed air supply can spoil the product and ultimately lead to a loss of valuable production. Therefore, the selection of the right product plays a vital role. 

Typical applications of compressed air in the chemical industry:  

1. Process air – Air used in direct contact with the product to clean, move the product and inflate the product. 

1. Control valves and cylinders – Valves of the pneumatic equipment used in the production process are controlled by compressed air. 

1. Material handling – Air-controlled pneumatic pumping system is used in volatile environments to lower the risk of explosion. 

1. Nitrogen production unit – Compressed air is utilised for nitrogen generation which is a critical gas in the chemical industry.  

1. Air curtains – Air curtains are used to isolate certain areas. Compressed air is passed through the curtain system to create a safe and clean area.   

1. Product drying – Compressed air is mixed into the product to speed up the drying process, wherever applicable. 

1. Fermentation and Aeration – Compressed air supplies oxygen to bacteria during fermentation and for oxidation. 

ELGi Air Compressors for Chemical Industry: 

ELGi air compressors are equipped with superior quality safety features and deliver industry-standard compliant standards of compressed air. They come with one of the best warranty programs in the world and have a low maintenance cost. The consistent air quality and energy efficiency makes them an ideal choice for the chemical industry applications. Check our compressed air solutions, oil-free screw air compressors, lubricated screw air compressors and others.

ELGi offers compressed air solutions for clean, dry, and oil-free compressed air as per your customized requirement.  Speak to our compressed air experts for your industry application solutions. 

After the air is being compressed in an oil flooded compressor, the air oil mixture enters with high velocity into the Air Oil Separator tank. Here it undergoes a unique and efficient 3 stage separation process which removes the maximum oil content.  

This process uses the impact velocity of the air oil mixture, along with centrifugal action – making the mixture very lean.  

The final stage of this separation consists of passing the lean mixture through the Air Oil Separator.  

What is an Air Oil Separator? 

An Air Oil Separator is a filter which separates the oil from compressed air. Thus leaving the compressed air with an oil content of < 1 ppm. 

Air Oil Separation done by a coalescent media (separator element) 

Importance of Air Oil Separator: 

An Air Oil Separator plays a key role in the separation process. It ensures that only the air and no oil is delivered to the outlet. Hence it is important that the separator should be replaced from time to time. Care should be taken that an authentic separator needs is used.  

Following is the significance of on time replacement and use of genuine separators. 

Importance of On Time Replacement: 

• Pressure drops across the separator: 

Pressure drop increases due to prolonged use and use of poor-quality separator. The pressure difference across the separator element directly converts to power cost. 

• Additional cost and change in system: 

The compressor capacity decreases due to flow restriction by clogged separator element. It can even reach a point of 12% in extreme conditions. 

The compression ratio of 7 bar machine increases to 9.64 (extreme condition). At this ratio, the load on bearings will be quite high! . 

A 30-kW compressor will cause you an additional power cost of INR Rs.5000, due to separator replacement delay by just 10 days of continuous operation. Timely replacement can avoid this unnecessary expense. 

Importance of using genuine Air Oil Separator: 

• Safety hazard: 

Usage of inferior quality parts will result in serious damage, including the possibility of a fire accident. 

Inadequate earthing can cause a separator to collapse (25% risk). It may causes fire and may also destroy the entire machine. 

• Reduced machine performance: 

Spurious separator leads to additional resistance for air flow. It creates more pressure drop and thus puts additional load on the motor. Inadequate separation deteriorates air quality, reduces performance, and damages the downstream components. 

• High power consumption: 

Due to  dense in filtration media, additional pressure drop is created.   

This causes additional power consumption. Every 1 bar (14.5 Psi) of pressure drop results in ~ 7% additional power consumption.  

Refer the table below for impact of Differential Pressure across the separator on performance. 

Do you want to know more on the importance of an Air Oil Separator? 

Contact the ELGi Air Experts who will guide you further.  

The ratio between the active power and the apparent power cos Ǿ is known as the power factor. 

The line current drawn by induction motors consists of two components, Magnetizing current and Power-producing current. 

The magnetizing current is the current which is required to produce the magnetic flux, and this component is lagging the voltage vector by 90 Deg (Lagging because vector rotation is anticlockwise) 

The power-producing current is the current which reacts with the magnetic flux to produce the machine’s output torque of the motor, and this component is in the time phase with the voltage. This means that the phase of the motor current (vector sum of the magnetizing and power-producing current) will be displaced about the network voltage by the angle Ǿ 

Why raise the power factor? – 

A motor running under no-load consumes almost only reactive power. 

Active power: The power consumed in an AC circuit is called active power. Active power is the power that continuously flows from source to load in an electric circuit. 

Reactive power: Reactive power is the power that continuously flows from source to load and returns to the source in an electric circuit. 

Plants containing many motors consume a considerable amount of reactive power. If the machines run at no load for a more extended period. In that case, the reactive power requirements will also be large compared with the need for active power, and the power factor can become very low, affecting the power tariffs. In this condition, it is a must to correct the power factor.  

By improving the power factor, we can achieve extensive savings. 

The total apparent power of the utility power will reduce, reducing the generating losses throughout the complete supply and distribution system. 

A higher power factor reduces the load on transformers and distribution equipment.  

The losses in transformers and distribution cables are proportional to the square of the line current. So, a high-power factor will result in a direct saving of electric power. 

How to improve the power factor: – 

The reactive power component (KVAr) must be reduced to improve the power factor for a given load.  This component of reactive power lags the power component by 90 Deg.  So, one way to reduce the effect of this component is by introducing a reactive power component that leads the power component by 90 deg. This can be accomplished by using a power capacitor, as shown in the power diagram resulting in a net decrease of the angle Ǿ=Ǿ1-Ǿ2 of an increase in the power factor. 

The amount and location of the corrective capacitors must be determined from a study of the distribution system and the source of the low-power factor loads. 

Where to locate capacitors: 

The power factor correction capacitors should be connected as close to the low-power factor load as possible to reduce the system losses. 

In some cases, the capacitors can be located at a specific power feeder. 

In other cases, with large motors, the capacitors will be connected as close to the motor terminals as possible. 

The power factor capacitors are connected across the power line in parallel with the low-power factor load. 

The circuit diagram, power capacitor connected to the motor terminals. 

Connecting the power capacitors at the motor terminals and switching the capacitors with the motor load is a very effective method. No extra switch or protective devices are required and the line losses are reduced from the point of connection back to the power source. Corrective capacitance is supplied only when the motor is operating. 

The following points have to be considered. 

It is necessary to reduce the overload relay setting to maintain proper overload protection. 

Never connect the capacitors directly to the motor when open transition starting is used such as star-delta and autotransformer. 

In this case, self-excitation voltages or peak transient currents can cause damage to the capacitor and motor. 

In these types of installations, the capacitors should be switched with a contactor interlocked with the motor starter 

Size of the capacitor to be installed: 

The size of the capacitor should not be too large if the power factor correction on the motor is directly applied.  When the motor is disconnected from the supply, it runs as a generator as long as it rotates and the capacitor supplies the magnetizing current. 

If the capacitor is too large, it will produce a higher magnetizing current than expected, generating a higher voltage than its rated voltage. 

The selection of capacitors should be with a maximum rating corresponding to 90% of the no-load output of the machine. 

Air compressors consume significant amounts of energy to supply power for industrial applications. If you consider all the costs of running capacity, you will realize that any savings therein will lead to a positive impact on your overall power cost management. 

Water vapor in the compressed air needs to be eliminated to prevent damage & corrosion to the compressed air line & your pneumatic tools. The operational expenses may go up significantly, if this moisture is not eliminated from the system.  That is why compressed air dryers are critical to industrial manufacturing processes as they help in removal of moisture from the compressed air lines.

 
Different dryers for diverse applications 

Depending on the application, compressed air dryers come in different capacities and types. Each of these dryers is unique, with its benefits and disadvantages: 

1. Refrigerated air dryers 

Out of all the compressed air dryers, the refrigerated air dryer is the most popular and used across several applications. 

 Functions: 

• Cools compressed air to very low temperatures, allowing moisture suspended in it to condense into its liquid form.  
• Once the water has been removed, a dry stream of air can flow towards the application. 

 Application: 

Useful in manufacturing & service applications that require compressed air with no detectable condensable moisture. 

 Benefits: 

• Cost-efficient – both in purchase and maintenance. 
• Resistant to airborne oil particles.

 Considerations: 

• Not ideal for sub-freezing temperatures.
• Have a limited dew point capacity.

2. Desiccant air dryers 

They are usually the second step after a primary dryer like a refrigerated dryer. 

Functions: 

Utilize a porous hygroscopic medium like activated alumina, molecular sieve and silica gel to extract moisture from the air and dry it.  

Applications: 

Useful in moisture-sensitive industrial and commercial applications: 

• Mold & bacteria prevention. 
• Healthcare/medication prescription environments. 
• Food processing. 
• Textile manufacturing. 

 Benefits: 

• Constant, low dew points. 
• Moderate operating costs. 
• Suitable for use in harsh, isolated environments. 

Considerations: 

• High setup costs. 
• Air filtration needed to prevent desiccant degradation from suspended oils. 
• Purge air is often required.

3. Deliquescent air dryers 

Single Tower Desiccant dryers are used in smaller, more specialized applications where a continuous supply of clean, dry compressed air is not required. 

Functions: 

Utilize a porous hygroscopic medium like activated alumina, molecular sieve and silica gel to extract moisture from the air and dry it.  

 Applications: 

Useful in moisture-sensitive industrial and commercial applications: 

• Mold & bacteria prevention. 
• Healthcare/medication prescription environments. 
• Food processing. 
• Textile manufacturing. 

Functions: 

• The deliquescent desiccant type of dryer uses a hygroscopic desiccant material having a high affinity for water.  
• The desiccant absorbs the water vapor and is dissolved in the liquid formed.  
• These hygroscopic materials are blended with ingredients to control the pH of the effluent and to prevent corrosion, caking and channeling.

Benefits: 

• Low initial capital and installation cost.
• Low pressure drops. 
• No moving parts.
• Requires no electrical power.  
• Can be installed outdoors.
• Can be used in hazardous, dirty or corrosive environments.

 Consideration: 

• Limited suppression of dew point.  
• Desiccant bed must be refilled periodically.  
• Drainage of dissolved solution.  
• Regular periodic maintenance.  
• Desiccant material can carry over into down-stream piping if there is no after-filter and if the dryer is not drained regularly. Certain desiccant materials may have a damaging effect on down- stream piping and equipment.  
• Some desiccant materials may melt or fuse together at temperatures above 80°F. 

4. Membrane air dryers 

Efficient option for compressed air drying. 

 Functions: 

• Utilize specialized membranes containing microtubules to filter moisture.  
• The microtubules retain water while a stream of the dried air is permitted to flow through to a collection unit or required application. 

 Applications: 

Used in applications requiring dehumidification, food processing, and gas separation. 

 Benefits: 

• Remote operation without the need for electricity. 
• Quiet operation, no moving parts. 
• Easy maintenance. 

 Considerations: 

• Only be operated with uncontaminated air. 
• Require regular filter changes to prevent blockages. 

ELGi’s solution for moisture sensitive industries 

ELGi’s Airmate Desiccant Dryer is a heatless twin tower desiccant dryer that removes moisture through absorption onto a granular desiccant bed from the air supply. As compressed air flows up through a packed bed of desiccant in tower 1, water vapor is absorbed. Meanwhile, tower 2 is rapidly depressurized, and dry purge air from the outlet of tower 1 is fed through a purge valve, expanded to near atmospheric pressure, and counter-flowed down through tower 2 to affect the regeneration of its granular desiccant bed. When the desiccant in tower 1 becomes saturated with water vapor, the air supply is switched back to tower 2 after it has been re-pressurized, and the cycle continues.  

As default, all HLD models above 5X come with the following options. 

 Dew Point Stretch Cycle: It stretches the moisture loading time of the desiccant bed by increasing the drying time. A dew point meter at the outlet with a required dew point setting provides the signal for the stretch cycle. This reduces the purge of air per the air flow and dew point chosen. The purge occurs for the pre-programmed time during this time.  

Note – Dew point meter not in dryer scope.  

Purge Optimizer: It reduces the percentage of regeneration flow based on the front panel setting. It has 4 options 40%, 60%, 80% & 100% purge optimization cycles respectively. The settings correspond to flow or moisture load through the dryer. Separate LED Indicators for Tower Status, Purge Optimizer & Condensate Drain.  

To make sure that you choose the ideal air dryer for your system, here are some things to keep in mind: 

• Select the air quality your business requires. 
• Invest in high-quality systems, resulting in cost & time efficiency. 
• Get in touch with an ELGi expert; they can assist you while navigating ELGi’s range of air dryers.

Unlike rotary compressors that are designed to run continuously without wear or damage due to overheating, piston compressors cannot run continuously for extended periods as their design has a lot of moving parts, and the cooling and lubrication system is basic. Piston compressors thus have a specified percentage of time they can run without causing any sort of damage to the compressor.  

What Is an Air Compressor Duty Cycle? 

To understand the air compressor duty cycle it is important to first know what cycle time means. When it comes to piston compressors – they run on a start/ stop cycle; meaning when the desired maximum pressure is reached the compressor stops and starts back only when it reaches a set minimum level. The time between one stop and start is the total cycle time. 

The duty cycle is generally represented as a percentage. It is the time duration a compressors’s top block runs to provide pressurized air at a defined flow rate relative to the compressor’s cycle time.  

Why Is Duty Cycle Important? 

The duty cycle is important as it helps to understand how efficiently a piston compressor functions by stopping and starting during use. It helps to determine if a given compressor model will fulfil the air needs of the application when sizing the compressor system. 

It is also important for ensuring the optimum life of the compressor, as exceeding the recommended duty cycle can prematurely wear out or damage the internal components.  

Duty Cycle Deciphered  

If a piston compressor’s cycle time is 10 minutes, and it runs for 7 minutes during that time, then it runs on a 70% duty cycle, which means 3 out of 10 minutes the compressor will be resting/cooling down during a cycle.  

A piston compressor that specifies a 100% duty cycle does not mean it can run continuously, but it can provide air at a specific pressure and flow for the time it runs (In the above– said case it is 7 minutes) with the help of a storage tank. 

Why should Duty Cycle be optimum?  

Heat is generated due to friction while the compressor is operating. Primary source, which is the friction between millions of air molecules while getting compressed makes compressed air very hot. The secondary source of friction are the moving parts inside the compressing unit, which raises the temperature of the cylinder as high as 150 to 200 Deg c.  

99% of the industrial piston compressors come with a basic splash lubrication system –here the oil properties play a vital role in ensuring proper lubrication. Excess heat generation deteriorates the oil properties thereby impacting the lubrication.  

The cooling system is not as sophisticated as what is available in other types of compressors. In a piston compressor, the cooling is majorly forced air cooled with fabricated or casted fan pulleys mounted on the compressor shaft and Copper or Aluminium pipes acting as coolers. These require non-operational time to ensure sufficient cooling time and avoid further heat generation between cycles. 

Effects of running at 100% Duty Cycle 

Some of the effects of running a piston compressor at 100% duty cycle are 

• Piston seizure in the piston housing due to excessive heat in the cylinder 

• Vales expand and jam with continuous exposure to a higher temperature, causing catastrophic failure of the compressor 
• Changes in oil properties lead to higher oil carryover 
• Continuous exposure to higher temperatures leads to higher condensate formation in the receiver tank thereby increasing moisture carryover to the downstream equipment and to the end equipment 
• Higher maintenance cost due to quicker wear and tear of internal parts 

Recommended Duty Cycle 

It is critical to know that the 100% duty cycle on a piston compressor does not mean that it can run continuously. Doing so can damage the compressor, resulting in premature wear and higher maintenance costs.  

Different brands recommend different duty cycles based on their design standards. The ideal duty cycle recommended for piston compressors by ELGi is a 70:30 duty cycle.  

Always choose a compressor that best suits the application requirement!  

With continuous efforts by compressor manufacturers to lead the market on energy efficiency, superior performance, and reliability, it is critically important that the users of air compressors are aware of the advanced product options available in the market. The technological advances in control systems and the evolution of the Internet of Things (IoT) provide further motivation to upgrade the air compressors at the right time. Typically, Air Compressor Upgrades happen in every 3-4 years by manufacturers to improve energy efficiency, reliability, advanced features, etc., and it is worth the while to evaluate the need for upgrading your compressors.

Five critical factors to consider while upgrading your compressor

Energy Efficiency: Energy costs contribute to over 75% of the total life cycle cost (LCC) of a compressor, and is therefore the key factor in upgrading an air compressor. Once the energy cost of the existing compressor is determined (through air audit or a simpler total input power measurement), the benefits of a new compressor, in terms of energy costs, can be evaluated. In cases where the user’s duty cycle of the air compressor has increased significantly over time due to additional production activities, the savings will be more beneficial with shorter return on investment. Additionally, if the plant needs a higher flow for expansion, it is an opportunity to consolidate the need and evaluate for upgradation. The size of the machine (in kW) should also be considered, as the larger the size of the unit, the higher the savings potential.

Advanced features: Significant improvement in controller features, more intelligence through additional sensors, and evolution of IoT capability are further reasons to consider an upgrade. These features result in improved uptime, insights for improvement in energy efficiency, and inputs for optimized operational settings in addition to 24×7 remote monitoring from anywhere in the world. In plants where the failure of a compressed air system can result in heavy losses in productivity, these features are particularly critical. Improvement in consumables’ life and/or reliability is another factor. Recently, ELGi had doubled the life of oil filters used in its oil lubricated rotary screw compressors in several models. All these features not only make the compressors more efficient but also significantly more reliable and advanced.

Breakthrough products: Compressor users must also look out for breakthrough products that will result in superior performance. ELGi has recently launched a product, AB Series with a disruptive oil-free technology that will bring down the life cycle cost of an oil-free compressor significantly. Such breakthrough improvements provide an opportunity to improve overall plant efficiency and performance while meeting the users’ needs effectively. Growing production needs in a plant will also need a different compressor technology such as the transition to centrifugal compressors for larger volumes of compressed air as an example.

Unplanned maintenance costs: As compressors age and when they need frequent attention to keep them running reliably, the unplanned maintenance or repair costs will also increase. If the cost of repairs reaches a certain level (~40-50% of the compressor value), along with the lower energy efficiency of older products, it is an appropriate time to evaluate and upgrade your air compressor.

Return of Investment (RoI): Another important factor to be considered while upgrading the compressor is the RoI. With improv energy costs, the RoI can be evaluated to meet the customer’s target.

Energy costs account for approx. 30% of a production facility’s operating budget. That means nearly a third of all the money organizations invest into their plant, goes straight to the power bill. Power cost is a pivotal determinant of the overall cost to companies. 

Globally, business owners have embraced sustainable techniques to ensure   convenience, and efficiency in their facility, but is it possible to go too green? Absolutely. 

Considering the implications of global warming, ELGi introduced a Heat Recovery System, which enables the reuse of heat energy generated during the compression process for tasks like heating water. 

Refine Your Compressed Air System with ELGi’s Heat Recovery System 

ELGi’s Heat Recovery System can assist in using 78% of the waste heat generated by the compressor for other facility operations, such as heating water. As a result, there is no longer a need to purchase additional equipment to heat water, thus lowering CO2 emissions. The Heat Recovery System is an accessory which can be used with the ELGi EG Series rotary air compressor. Customers can easily plug the HRS into an air compressor to warm water and air for use in showers and boilers by using the heat produced by the air compressor.  

In a typical compression system, the theoretical recoverable heat is 96% of the overall electrical energy consumption. It consists of heat dissipated in the oil cooler (78%), the after cooler (13%) and the heat radiated from the drive motor (5%). The heat dissipated by the oil cooler can be used for heating water and the heat dissipated by the after cooler and drive motor can be used for supplemental space heating. The remaining 4% heat cannot be recovered, since 2% radiates through the canopy and the other 2% vents inside the canopy. 

Robust Operations Across Industries 

The Heat Recovery System finds its operation in industries like automotive, textiles, cement, paper & pulp, machine tool shops, steel making and the food processing industry where there is a need to heat / pre-heat water to a certain temperature ELGi’s HRS can significantly reduce energy costs by eliminating the use of special heating equipment or by offering the initial heat to start the heating process where higher temperatures are required. 

Elgi is a global air compressor manufacturer with an expansive line of innovative and technologically superior compressed air systems. ELGi has consistently ensured that its customers achieve their productivity goals while keeping the environmental impact low. Our product innovation for the Heat Recovery System is driven by the potential for savings and by examining the carbon footprint of an air compressor. ELGi firmly believes that sustainable technology is at the heart of positive environmental change.    

Explore our portfolio of sustainable & efficient solutions here: http://www.elgi.com