The article is written by Riya Veluri, an editorial team member of Industrial Lubricants. After her graduation, Riya works as a website developer & SEO specialist in Lubrication & Tribology Industry & writes technical articles on Lubricants, Lubrication, Reliability & sustainability.
What are Coolants?
Industrial lubricants are an always a huge and fascinating topic to discuss and share. Broadly industrial lubricants are discussed in two different verticals – one is, of course, Factory, Plant & Machinery (FPM) products such as Hydraulics, Gear Oils, Compressor Oils, etc. Another category is Lubricants employed in the process industry. The most sensitive portfolio of the latter segment is the extendable water-based cutting coolants used in the metal processing industry.
Coolants are fluids that transfer heat from devices to stop overheating. Coolants circulate through or around the devices to transfer heat to the outside environment for heat dissipation. Industrial coolants take heat from the engine or machine and then disperse it through radiators or other devices. Coolants for industrial use are also referred as antifreeze liquids. These are typically a mix of propylene and ethylene glycol, with water in a similar proportion. Antifreeze liquids have the same characteristics similar to industrial coolants. Antifreeze liquids can withstand high and low temperatures. These liquids are concentrated and made from glycol, with a few corrosion inhibitors and other ingredients. Antifreeze liquids are diluted in different proportions, incorporating additives that make industrial coolants in various types. Antifreeze liquids that are diluted are typically referred to as industrial coolants.
Properties of Industrial Coolants
Industrial coolants have key properties such as low viscosity and high thermal capacity. They also come with low cost, chemical inertness, non-toxic, low-cost, low-cost, and low-toxicity. The ideal industrial coolant will not cause corrosion to the cooling system or other parts of the engine/machine. Many industrial coolants are used across many industries, including automotive, oil and gas, power generation, chemicals, and chemical. Industrial coolants must maintain the engine temperature in all weather conditions without overheating or freezing. Industrial coolants are treated with special additives to prevent chemical deterioration or freezing. In addition, special anti-corrosive additives are used in industrial coolants to prevent internal corrosion of automotive engine/machine components.
Types of Industrial Coolants:
There are three types of industrial coolants that are widely used: green antifreeze coolants (IAT), OAT antifreeze coolants, and HOAT-anti-freeze coolants. The most widely used industrial coolants around the world are green antifreeze coolants. These coolants contain silicate and phosphate additives that protect cast iron, aluminium, brass and copper surfaces and machinery parts. OAT stands for organic acid technology. These industrial coolants include organic acids like sebacate, 2-EHA, or other organic acids. This type of additive package lasts much longer than those used in IAT coolant or green antifreeze coolants. HOAT antifreeze coolants are hybrid OAT industrial coolants. These industrial coolants are organic acids with silicates, phosphates, and phosphorous to protect aluminum and metallic surfaces on machinery and engines. Most of the big Car manufacturers like Chrysler, Ford, Mercedes, BMW, Volvo use the majority of HOAT industrial coolants.
In some applications, solid materials are also used as coolants. The materials require high energy to vaporize; the vaporized gases carry this energy away. This approach is common in spaceflight for ablative atmospheric reentry shields and cooling of rocket engine nozzles. The same approach is also used for fire protection of structures, where an ablative coating is applied.
Dry ice and water ice can also be used as coolants when in direct contact with the cool structure. Sometimes an additional heat transfer fluid is used; water with ice and dry ice in acetone are two popular pairings.
Coolant management best practices:
While purchasing high-quality tools is an important step in maximizing tool life, it is not the only consideration. The quality of the coolant plays an important role in tool life. As they are contaminated by metal fines, tramp oils, and bacteria, cutting fluids can deteriorate over time. Coolant can become ineffective if it loses its lubricity. This will cause tools to dull prematurely and break more often than necessary. Coolant can also cause damage to electronic components, pumps, sumps, and other machine tools as it breaks down. The interiors of machines and equipment are more susceptible to corrosion and rust, while the surfaces of equipment suffer from abrasion. Tramp oil mist can cause mechanical failures that prematurely block air filters and clog prematurely.
It is important to check and maintain the machine coolant levels regularly. Operators should monitor and adjust the coolant levels in their machines every day. This is an important step in optimizing coolant use. Also, keeping track of the coolant levels, such as volume and pH, can help you monitor trends and decrease instances of coolant-related issues. For example, coolant can be wasted if it is too concentrated. This could also lead to inadequate cooling. Conversely, low concentrations can cause decreased tool life, coolant spoilage, and product defects.
Sump volume should be maintained at 85-100% to minimize pH fluctuations and concentration fluctuations. In addition, the proper coolant concentration can be monitored and maintained to reduce coolant consumption, tool life, product defect, and time and save money on coolant costs.
Precaution during Mixing Coolant with Water:
Full-strength coolant needs to be combined with water to work properly, as you probably know. Hard water can have a significant negative effect on the effectiveness of additive packages. Coolant manufacturers use distilled/deionized water for their premixed formulations. All OEMs and coolant manufacturers recommend mixing full-strength coolants with distilled/deionized water.
Coolant Filtration Principles:
Filtration refers to separating particles from fluids by passing them through a porous medium. Non-filtration methods include gravity settling, flotation, centrifugal force, cyclones or centrifuges, and processes like reverse osmosis or ion exchange for the separation of dissolved solids.
Filtration of liquids is done for four reasons:
(1) To save the solid particles and discard the fluid.
(2) To save the liquid and discard the solids.
(3) To save both.
(4) To save neither.
Automated Coolant Recycling System:
The most important parameter to extending tool and coolant life is continuous monitoring of coolant to ensure it meets the manufacturer’s recommended concentration levels. However, testing coolants, adjusting coolant concentration levels, and treating contaminated coolants using biocides is time-consuming.
Coolant recycling equipment automates coolant quality management by separating solids from liquids and removing mechanically dispersed and free-floating contaminants such as bacteria and tramp oils. These systems can also adjust fluid concentrations for fluid recovery.
Recycled coolant can reduce sump maintenance, increase part quality, and extend tool life. According to case studies, coolant recycling equipment can increase tool life by as much as 25%. The benefits of automated fluid recycling can go beyond the tools themselves. Coolant filtration systems and recycling systems dramatically reduce fluid purchasing costs and hazardous waste disposal costs. Compared to the usual change-out period, the coolant can be extended up to five times by these systems. In addition, the unfortunate side effects of dirty coolants, such as dermatitis and foul odors, are eliminated by automated systems.
Coolants Recycling Equipment Overview:
Here we try to demonstrate different types of common fluid recycling and filtering systems.
Centralized Coolants Recycling Systems can remove suspended solids and tramp oils from contaminated coolants. They also control bacteria and adjust fluid concentrations for fluid recovery.
Here is a YouTube video of centralized coolants recycling system:
Other than centralized coolant recycling systems, magnetic and standard paper bed filters can extend the tool life by 27% on average, improve surface finishes, and prolong coolant life. In addition, they also remove solids from industrial process fluids that are free-flow and can also reduce coolant consumption.
Magnetic separators use high-intensity rare earth magnets or ferrite in a rotating drum to remove ferrous particles continuously from the flow of liquid. This can help reduce downtime by approx 50%.
Here is a YouTube videoof Magnetic coolant separator: