The main function of the fluid in a hydraulic system is to transmit a force applied at one point to another point. The power must be transferred quickly and with precision. All quality hydraulic fluids must be capable of fulfilling the following functions:
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Transmit power: transfer of a kinetic or potential energy (movement or pressure)
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Lubricate and protect: protection against wear on surfaces in contact In order to best fulfill these functions, a hydraulic fluid must have a certain number of properties, appropriate viscosimetrics, shear stability, fluid behavior, right viscosity and little variation in viscosity in relation to temperature.
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low compressibility (rapid de-aeration and low foaming)The viscosity grade has to be chosen depending on the in-service temperature. Actually, the in-service lubricant has to maintain a viscosity higher than 10-15 cts in order to lubricate the pump. OEMs’ recommendations have to be followed.
The choice of a hydraulic lubricant should take into account the following parameters:
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OEM requirements
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Appropriate viscosity
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Is a high VI required?
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Anti-wear properties (FZG level should be indicated)
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In service fluid behavioral needs: shear stability, foaming properties, demulsibility.
Viscosity of hydraulic oil is one of the most critical properties. The right viscosity:
Hydraulic equipment functions in a defined viscosity range. It is therefore important to supply a hydraulic oil of the right viscosity in order to guarantee optimum functioning of the installation.
Insufficient viscosity leads to breakdowns in the oil film, and therefore, wearing on the moving parts. Consequently, losses are increased. On the other hand, an excessive viscosity has a negative impact on efficiency, heat exchanges and may lead to cavitations phenomena in pumps.Note: the impact of pressure on viscosity should not be forgotten (viscosity increases with experienced pressure).
High viscosity index - for applications over a wide temperature range:
For the application in various climatic conditions, it is important to guarantee an appropriate viscosity over the whole temperature range, hence the importance of the viscosity index for these applications.
The higher the viscosity index, the lower the variation in viscosity in relation to temperature. A high viscosity index enables proper functioning over a much wider temperature range.
For some specific applications, the hydraulic oil must have certain additional properties.
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Low flammability. In order to limit the risk of fire, certain applications (steelworks, mines, etc.) require the use of fire resistant fluids.
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Suitability for incidental food contact. For the food and pharmaceutical industrial oils "suitable for incidental food contact" may be required.
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Biodegradability. For applications in which the oil may be in contact with the environment, biodegradable lubricants can be proposed, in order to limit the impact on the environment.
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Viscosity Index (VI)
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The influence of air and water on the hydraulic oil properties
Shear stability: Addition of a viscosity index improver (VII) enables a widening of the functioning temperature ranges of hydraulic fluids by altering the viscosity at higher temperatures. However, there is a variety of VIIs which have different shear stabilities. VIIs are polymers (long carbon chains) which may be cut into smaller chains when subjected to shear. When this occurs to significant levels, the viscosity index is reduced and the operating viscosity may no longer be suitable for the operation. The use of VIIs with good shear stability is required for optimal performance in use.
Fluid behavior when subjected to air and water:
Air and water acts as pollutants for hydraulic fluids. Their presence increases the fluid’s compressibility, which leads to reduced precision in the transmission of the force and/or movement. In addition, they may cause breakdowns in the oil film and reduce the duty life of the operating oil. The properties enabling separation of the oil with these pollutants are crucial. Foaming and Air release properties are important indicators of interaction with air. Demulsibility indicates the degree of interaction with water.
Many considerations have to be factored in selecting a gearbox lubricant:
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Gearbox type: dimensions, the metal from which the teeth are made, sliding properties and gear ratio, open or closed casing, etc.
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Operating conditions: depending on the load, vibration and shock levels, anti-wear and extreme pressure properties determine the choice of lubricant.
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Service oil temperature: very low, moderate of between +20°C and +80°C, hot at more than +80°C and extreme at in excess of +120°C.
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Possible effects that the gearbox's environment might have on the lubricant: some oils have enhanced anti-corrosion properties to maintain the length of the fluid's service life in the event of exposure to humidity, dust or other elements.
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Possible effects that the lubricant might have on the gearbox's environment in the event of a leak: biodegradability, food-grade or non-staining properties may be required.
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Maintenance conditions: a synthetic fluid that can allow long intervals between oil changes and which guarantees high levels of operational safety can result in significant maintenance cost savings
In standard operating conditions, mineral oils perform very well, providing perfect lubrication at oil bath temperatures up to 80°C, in continuous operation. Synthetic oils can be used with machinery that operates at higher temperatures of up to 120°C or 130°C. However, in operating conditions that reach a maximum of around 80°C, a synthetic lubricant will oxidize to a lesser extent than a mineral oil and could double or even triple the oil bath's service life under certain conditions.
There are four main families of gearbox oils:
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Mineral oils
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Poly-alpha-olefins (PAOs)
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Esters
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Polyglycols, also referred to as Poly Alkylene Glycols (PG or PAG)
Mineral oils, PAOs and esters may all be mixed together.
Only Polyglycols type synthetic oils (PG or PAG) may not be mixed with the other lubricant types. They can react together and form gum gels in the casings. Furthermore, they can sometimes be incompatible and immiscible with other Polyglycols.
A chain's service life depends mainly on its lubrication system. In fact, a study has shown that 60% of chain defects can be attributed to insufficient or inadequate lubrication. Lubrication flaws are behind many different forms of wear (adhesive wear, abrasive wear, wear caused by small amounts of play between surfaces, corrosive wear, etc.). Wear on an axle / socket can lead to the chain being lengthened, while wear on the roller will affect the play between the socket and the roller.
Throughout the service life, the lubricant used has several roles to play:
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It forms a film between surfaces that rub together (axle/sockets, sockets/rollers and rollers/teeth), as well as between internal plates and external plates, rollers and the teeth. This is so as to prevent (as far as possible) metal parts coming into direct contact with other metal parts, irrespective of operating conditions (load, temperature, etc.);
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It ensures that the lubricant film remains elastic so as to cushion the meshing jolts between axles and sockets and between sockets and rollers, as well as reducing noise;
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It has to be present in sufficient quantities in the drivetrain's moving parts and it has to have appropriate physical-chemical properties to be able to remain in these articulations (Extreme-Pressure);
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It has to protect the drivetrain against stresses from the ambient environment. In particular, it has to protect it against oxidation and corrosion;
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It has to evacuate heat energy generated by friction for high-speed transmissions in particular.
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If all of these conditions are met, the lubricant can help reduce the friction coefficient and so save energy. This reduces wear on the drivetrain and so helps ensure that the transmission system operates properly.
For it to be effective, a lubricant has to penetrate into the articulation and work in the places where there is friction. It therefore has to be applied:
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On the inside-facing sides of the chain strands. Otherwise, the centrifugal force would prevent it reaching the surfaces that rub together;
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On the slack strands, near where the drive pinion disengages so as to take advantage of the loosening of the articulations in order to reform the oil film which had been partly driven away by the forces exerted on the taut strand, as well as by centrifugal force (there can be additional lubrication points where the drive and driven opinions engage);
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On the interior plates, such that the lubricant works its way between the interior and exterior plates to feed the axle / socket articulations, as well as between the interior plates and the rollers to feed the socket / roller surfaces.
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The significant role played by centrifugal force is therefore understood, together with the overall kinetic energy of movement in lubricating articulations: the term used is "lost lubrication". When a chain is correctly lubricated, a film of oil remains in the articulations (mixed lubrication) when movement starts, thus reducing contact between metal surfaces.
It is known that the service life of a conveyor or transmission chain depends on it being properly lubricated. More specifically, the lubricant should insert itself as a thin film between metallic surfaces that come into contact with one another in the chains, and the surfaces between the axles and the sockets, and the surfaces between the plates.
To be able to do this, the lubricant has to be fluid enough to penetrate into the articulations and between the plates, and has to have a high wetting ability: preference should be given to lubricating oil.
However, in some cases and / or for some applications, the manufacturer will prescribe the use of greases. Most of the time, chains operating in a humid atmosphere and / or humid environment (when the manufacturing process involves their total or partial immersion) will need to be lubricated (for example: sterilizer in a cannery). In this case, chains will be designed to be lubricated using greases - there will be grease channels in the axles so that the surfaces between the axle and the socket can be lubricated - or they will be larger so that surfaces that come into contact with one another can be lubricated using a greased pump.
Lubricants for chains need to have the following properties:
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An appropriate level of viscosity so that it can reach the interior surfaces that need to be lubricated,
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Enough lubricity to maintain a lubricant film at high loads,
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Sufficient adhesion so that the greases stay on the chain,
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Good anti-corrosion properties at all temperatures,
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In some cases, the ability to withstand variations in temperature without deposits forming when the lubricant breaks down.
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Meeting all chain lubrication requirements with a single product is not a completely realistic target. A lubricating formula is first and foremost a subtle compromise of varying types of performance - some of which can sometimes be contradictory.
Cleaning of an industrial chain is necessary and can be done with various solutions depending on the situation.
It is advisable to clean chains periodically, particularly when relubricating them. Chains which operate in the open air, chains which are manually lubricated or lubricated using a drip system and chains which are exposed to dust should all be cleaned in particular. When changing the lubricant in casings and pressurized lubrication systems, the chain should be cleaned, together with the whole lubrication system.
Careful selection of the cleaning product is necessary to avoid any damage in the chain. Acidic products in particular should not be used to so as to avoid weakening the chain material. The chain should be cleaned using pressurized water and then re-lubricated using a suitable product (with water displacement properties).
As a general rule, the cleaning products should be carefully chosen based on the types of deposits found on the chain and the level of dirt:
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A very fluid oil: will not prevent re-lubrication with an oil of the same type but one that is more viscous;
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A solvent: can be used to remove coked deposits on chains that operate in hot environments. Air blowing can be used to remove any remaining solvent prior to re-lubrication;
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High-pressure steam and water jet with detergent: can be used to easily remove amalgams. The chain should then be rinsed quickly with water in order to remove any traces of detergent, and then blown with air before being quickly re-lubricated (to prevent any corrosion).
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Brushing the chain will prevent clogging.
As a general rule, a gearbox lubricant meets the requirements of an international standard, such as ISO (ISO CKC or ISO CKD) or DIN. A manufacturer prefers or approves a lubricant in relation to those international standards, but also on the basis of its own criteria; for example, compatibility with paints (or seals) that they use. From a mechanical perspective, the risks are practically zero if the product is in compliance with the international standard in question, and the standard required by the gearbox manufacturer. The need for a product to be approved mainly has to do with security issues during the warranty period for the manufacturer.
Fluid Oxidation: The oxidation of a heat transfer fluid can considerably shorten its lifetime; the reaction requires air and temperature to take place so these two parameters need to be adjusted to minimize their effects. The place where fluid can come into contact with air is the expansion tank. Working on this equipment to limit any contact between air and heating oil must be monitored.
We recommend installing the following devices if possible:
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Put the expansion tank under a nitrogen blanket or place a floating lid on the surface of the oil.
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Maintain the oil temperature below 55°C/60°C; this can be done by cooling the pipe connecting the expansion tank to the remainder of the circuit.
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The expansion tank must be in a ventilated place whenever possible.
Segmentation of insulating oils depending on their standards.
The specifications required in terms of the physical-chemical properties of insulating oils are summarized in the international specifications. The most frequently used specifications are IEC 60296 and ASTM D3487, which are applicable to naphthenic or paraffinic mineral oils.
The IEC 60296 specification divides insulating oils for transformers into three categories, based on the levels of antioxidants (also referred to as inhibitors) contained in the oil.
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"Non-inhibited" category (U): antioxidant content = 0%
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"Slightly inhibited" category (T): antioxidant content < 0.08%
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"Inhibited" category (I): antioxidant content < 0.4%
The ASTM D3487 specification divides insulating oils for transformers into two categories, based on the levels of antioxidants contained in the oil.
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Type I: antioxidant content < 0.08%
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Type II: antioxidant content < 0.3%
Other standards exist which apply to ester-based products:
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IEC 61099: Specifications pertaining to new synthetic organic esters for use with electrical equipment
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IEC 62270: Fluids for electro technical applications - new natural esters for transformers and similar electrical equipment
The specificity of a lubricant for refrigerating a compressor is that it permanently contains a small quantity of refrigerant. The lubrication must therefore still be good in the presence of this small quantity of refrigerant. In the case of ammonia being the refrigerant, there is a total immiscibility between the lubricant and the refrigerant. It is important that the lubricant has a pour point lower than the temperature of the evaporator to ensure functional operation. Furthermore the reverse also occurs: the lubricant is pulled in small quantities into the refrigerant and goes through the refrigerating installation cycle. Therefore it must first endure a long exposure to the pressure and temperature and so must have a good thermal stability in the presence of ammonia (it is necessary to avoid the formation of black sludge).
About heat transfer fluids and their classifications in ISO 6743-12 standard.
In a heat exchanger, heat moves from the heat source into the moving fluid through a thin film of fluid. If the temperature of this fluid film exceeds the maximum recommended film temperature, the chemical bonds holding the molecules together start to break apart, the fluid will degrade, and the fluid life might be shortened. In the circuits, thermal cracking will cause deposits formation, pump cavitations and loss of heating capacity.
The ISO 6743-12 standard establishes the detailed classification of family Q (heat transfer fluids).
Temperatures indicated in the table are those of the bulk fluid, measure in the discharge line from the heater. Film oil temperatures may reach higher values.
Unlike "mineral" oils which are manufactured by distilling crude oil and then subjecting it to special processing, "synthetic" oils are manufactured in the chemicals sectors by adding together identical molecules in order to obtain oils of varying levels of viscosity.
The main synthetic oils are synthetic esters that are often used to create biodegradable lubricants, polyalphaolefins (PAO), whose chemical composition makes them very similar to mineral oils, and polyalkylene (PAG), glycols which have improved lubricating capacities.
The main advantages of mineral oils - apart from the special benefits derived from their molecular composition (biodegradability for synthetic esters, for example) - include a better ability to withstand ageing (meaning a longer service life) and the fact that they can be used over wider temperature ranges, giving them more multi-grade properties than traditional mineral oils.
Composition of a grease; main components.
A grease is made up of the three following components:
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thickening agent 5% to 20%
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base oils 80% to 95%
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additives 0% to 10%
The thickening agent - be it a soap or something else - has a tremendous bearing on the grease's performance.
A grease is a semi-fluid product made up of a lubricating fluid, a thickening agent or soap and performance additives.
Thickening agents are divided into soaps, gels and mechanical thickeners.
How soaps work: As far as soaps are concerned, the most common representation is of a sponge which contains the elements (oils, liquid and / or solid additives) that lubricate the contact (ball on a track, meshing of gear teeth, etc.).
In a roller bearing, for example, the rolling component, just like a steamroller, compresses the grease. This releases oil, preventing all metal-on-metal contact and facilitating the rolling. During the idle phase, the grease partly recovers its oil. For the same type of soap, a grease with more soap will have a tendency to release less of its oil. This phenomenon is more or less desired depending on the application (long service life), bearing in mind that if too little oil is released (the term used is "bleeding"), the contact will be improperly lubricated. It's a question of getting the balance right!
Gradually, the steamroller - like a sponge that is subjected to a scissors action - shears or breaks the soap. The grease then loses its consistency, is no longer able to retain the oil as effectively and so escapes from the roller bearing. The parts then have to be re-greased.
The parameters to be monitored:
Significant increases in temperature and / or noise and vibration; this could be an indication of changes in the grease's operating conditions.
The state of the grease: during maintenance operations, it is a good idea to check that the grease has not been polluted by any foreign bodies
Changes in consistency: Areas of the grease may harden - this can sometimes be a sign that the grease has lost some of its lubricating oil. Conversely, if the grease has lost some of its consistency, that can be the result of a mix leading to a deterioration in its qualities. In both scenarios, questions should be asked about how suitable the grease is for the application in question.
When talking about lubricants, ash refers to mainly the metallic compounds in the oil. This ash is mainly derived from the chemicals used in anti-wear additives and detergents, as well as solids - including calcium, zinc and molybdenum. But these chemicals, which are frequently used in engine oils and hydraulic fluids, also have a number of disadvantages. They can lead to the formation of deposits in humid environments or at very high temperatures and can result in high levels of eco-toxicity for the environment - particularly when heavy metals are used.
Ashless industrial oils are therefore lubricants that are formulated without metallic additives, and which are mainly used for the following purposes:
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circulation oil used in a humid environment
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environmentally acceptable oil
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Food grade oil
The definition is considerably different as far as engine oils are concerned: an "ashless" engine oil actually has a limited ash content (less than 0.01%). This is so as to prevent the pollution control systems from getting clogged up or poisoned.
he alternatives to ash forming oils:
Formulating ashless oils involves selecting additives that contain no metal compounds. The challenge for ashless oils is therefore to provide a level of performance that is appropriate for whatever it is they are being used for, but without all the disadvantages of ash forming oils.
Preference is given to ashless oils in the following cases:
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Circulation oil used in a humid environment (paper machine, machine tool, rolling mill)
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Biodegradable oil
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Food grade oil
Compatibility between ashless oil and ash forming oil:
Two lubricants can be incompatible because of the base oils that they use, as well as because of their additive types. Several laboratory compatibility tests between ashless mineral oils and ash forming mineral oils have resulted in the formation of deposits. This would suggest that the two additives are often incompatible. Consequently, should there be any doubt about the compatibility of an ash forming oil with an ashless oil, a specific laboratory test will need to be carried out.
Recommendation to ensure the cleanliness of the new oil when filling a machine.
THE 4 KEY RULES:
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Check that you are using the same oil or grease as the lubricant already in use in the machine.
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Use a clean container to transport the oil or a different grease pump for each grease type.
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Clean the top-up area in order to keep all pollution generated by the top-up operation to a minimum.
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Adhere to the recommended quantities and levels.
Recommendation for keeping oil circuit as clean as possible filtering the used industry lubricant.
Just like blood in the human body, oil circulates throughout all the components of a lubrication circuit. During its journey, it becomes loaded with various pollutants. Contaminants fall into 3 categories: mineral - most often silica (earth, sand, etc.), vegetable or synthetic - such as pieces from the seals, flakes of paint, fiber from cloths, etc. and metallic, such as steel, iron, yellow metals that are the result of wear or running in.
A large particle in the wrong place at the wrong time can cause a major fault in the circuit. This is why a properly configured filtration system is required in order to maximize the reliability of lubricated equipment. How effective this filtration works depend on how accurate the level of cleanliness required or recommended by the hydraulic circuit's designer, also depending on what it is used for and its design.
Maintaining industrial machinery must be realized with strict procedures; taking samples of the lubricating fluid is one of the most important procedures to follow.
First of all, the sample taken needs to be representative of the oil load to be analyzed and / or has to provide the most reliable possible analysis of the state of the lubricated component: the location of the sample taken is therefore of key importance and should always be the same depending on the type of information required.
The sample must always be taken in accordance with a predefined procedure. This procedure must be rigorously and strictly applied for each sample taken so as to maximize the reliability of the analysis and ensure that it is consistent with all previous analyses for the same given machine.
The equipment used to take the sample and the containers into which the oil for analysis will be collected must all be completely clean so as to minimize the risk of errors in the analysis.
Each container containing an oil sample for analysis must be correctly labeled and should include all the information needed for an accurate analysis. This will ensure a reliable analysis history and is vital for tracking changes in operating conditions and levels of wear on the machine in question.
Filling a machine with an oil that has a very low pollution class involves significant investments in order to ensure that this property is maintained right up until it enters the inside of the hydraulic circuit, without absolute guarantees in terms of the results.
Here are 4 critical phases during which there are risks of oil being polluted, meaning that particular caution is required:
The oil may be polluted during production at the factory. Producing very clean oil involves additional processing in additional industrial machines.
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The packaging used to transport the oil is exposed to stresses and so ages over time. Polluting particles can enter the oil. For this reason, oil that is delivered in bulk is cleaner than oil that is packaged in drums - there is no opportunity for pollution from the drum to get into the oil.
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Drums "breathe". As the temperature varies, exchanges between the exterior and the inside of the drum take place, allowing air containing pollutants to enter.
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There is another risk of the oil being polluted when it comes into contact with air or unprotected decanting components as it is transferred from its packaging into the circuit.
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It is therefore far more profitable and efficient to filter the oil as it is brought into service or alongside the circuit, while the machine is in operation.
Furthermore, it is the only way of making sure that the level of cleanliness required by the equipment is obtained.
Before any change or complement of lubricant in machinery, it is essential to ensure their mutual compatibility.
A compatibility test carried out in a laboratory might be necessary. Some well known cases showing compatibility issues:
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Synthetic oils based on polyalkylene glycol (PAG) are incompatible with mineral oils and other synthetic oils. Oils formulated based on PAG are also not all mutually compatible.
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Ash-forming oils, for example oils containing zinc dithiophosphate additives, are generally not compatible with ashless oils.
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Replacement of fluid grease with oil.
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Replacement of a grease by another incompatible grease
The hardness of a water supply is determined by the content of calcium and magnesium salts. Calcium and magnesium can combine with bicarbonates and chlorides for instance to precipitate as solids mineral salts which make water more corrosion aggressive on many materials.
A rust preventive is used to isolate the metal from its environment (water, oxygen) thanks to a protection film.
Corrosion is the result of chemical reactions between metallic materials and their environment.
If corrosion is due to the oil, and then the oil must be changed. If the corrosion occurs because the oil is not protecting enough against the corrosive atmosphere, then the oil must be switched to oil with better anti-corrosion properties.
Counting particles reveals how many solid contaminants there are in the oil sample analyzed and how big they are. Counting particles provides essential information for monitoring:
The cleanliness levels of fluids used in circuits that require products that are completely free of solid pollutants. Various standards are used for checking articulations:
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ISO 3722: For approving and checking container cleaning methods.
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ISO 4021: Describes the various procedures for extracting samples from a system in operation.
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ISO 4405: Describes the method used for determining the total mass of pollutants obtained by filtration.
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ISO 4406: Defines a method for coding pollution levels.
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ISO 4407: Describes the method used to determine the level of particulate pollution by counting the particles under an electronic microscope.
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ISO 11500: Describes the method used to determine particulate pollution using an automatic particle counter that works according to the light-extinction principle.
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NAS 1638: Defines a method for coding pollution levels (a different method to the one described in ISO 4406)
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SAE AS4059E: Equivalent to NAS 1638, developed as its successor.
It is noted that the most frequently referenced standards (ISO 4406 and NAS 1638) only relate to the format in which the results are expressed, not the methods used to take samples or perform analyses.
Because of the natural properties of esters and the specific additives developed for these oils, biodegradable lubricants surpass mineral oils when it comes to viscosity/temperature behavior, total shear strength and anti-wear properties. Under the right operating conditions, using biodegradable oils can lead to enhancement of oil change intervals compared to standard mineral oils.
White oils are highly refined mineral oils that are extremely pure, stable, colorless, odorless, non-toxic and chemically inert. These attributes make them perfect for any application that values these properties, such as pharmaceuticals, cosmetics and chemical processing.
The term "white oil" is a misnomer, in that they are not white at all, but crystal clear. White oils can be produced from a variety of feedstock, depending on the process used. These starting materials include conventional base stocks for the older acid treatment process to Vacuum Gas Oils (VGO) for the more currently widely used two stage hydro treating method. Both processes produce colorless, odorless, tasteless oils where all components that might have any detrimental effects on their end usage, such as aromatics, sulfur or other impurities have essentially been removed, resulting in a pure and thermally stable product.
Thanks to these characteristics white oils are widely used in pharmaceutical and medicinal applications, cosmetics, and the plastic and food industries.
Biodegradability is defined as the ability of a molecule to be degraded biologically i.e. by the action of biological organisms.
Biodegradable oils are combinations of selected biodegradable bases (vegetable oils, rape, sunflower, synthetic esters) which are non-toxic, and special additives which give them their desired properties. Needless to say, the choice of base oil is fundamental and will determine the oil's performance and its service life.
A food grade lubricant may be selected for a number of reasons: a desire to minimize risk as much as possible for the end client, the desire to meet the requirements of a critical control point approach (e.g.: HACCP) or of a standard (e.g.: ISO 22000) or regulation.
Whatever the reason for this choice, the machine's overall oil feed must be deemed permissible for accidental contact with foodstuffs.
The permissible level for contamination as far as an NSF H1-registered product is concerned is 10ppm - i.e., 10 g per production tonne. By extension, for a product that is not appropriate for accidental contact with foodstuffs, the permissible residual content is zero: 0 ppm. This also applies to products that are registered as NSF H2.
This means that the facility has to be systematically flushed when switching to a food-grade lubricant. The procedure used should remove as much of the old lubricant as possible, depending on the type of equipment in question: gearbox, with or without oil circulation, hydraulic circuit, heat transfer fluid facility, compressor, air lubricators, etc.
When water is mixed with oil very quickly; this unstable mix separates into 2 phases, with water on one side and oil on the other. An emulsifying agent is therefore required to bind these two water and oil phases into a stable mix.
The resulting mix's equilibrium depends on the emulsifying agents being suitably arranged, linking the water and oil molecules together. Whether or not a good balance is achieved is determined when the two liquids are mixed together. Care should therefore be taken and the oil should be poured gradually into the water. The emulsion will remain stable if the oil molecules are dispersed into the water and not the other way round - which would result in something similar to mayonnaise (water molecules dispersed in water).
Storage of oil. Management of stocks for the right level of the right quality lubricant or grease.
The method of lubricant storage (bulk, container, drum, can) must be determined according to the volumes stored, the consumption of lubricants, supplier delivery deadlines but also maintenance procedures. Making the right choice of containers allows you to avoid having too large stocks that lead to capital costs and increase the risk of exceeding the expiry date for using the products. An adapted storage method also limits the risk of pollution and degradation of the product during its storage time.
Safety and usage of lubricants in ATEX zone in industry.
Some industries, by their nature, are subject to a particularly high risk of explosion. For combustion to occur, the following three elements are required:
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Fuel in a finely dispersed form (vapor, gas, powder, fog, etc.). Oil can only play this role when it is used at temperatures that are higher than its flashpoint. This is only the case in heat transfer circuits. These should have their own specific risk analysis carried out on them.
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An oxidant, usually the oxygen in the air
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An ignition source to provide the minimum ignition energy
In industry, the oxidant is usually the oxygen in the air and the fuel is usually the one used in the manufacturing process: gas, steam, dust, etc. The purpose of the standards pertaining to equipment for use in ATEX zones is to prevent an ignition source from being brought into them by using equipment that has been specially protected in these zones.
Although there are no oils that have been specifically formulated for use in ATEX zones, oils play a particularly important role in insulating certain pieces of equipment, such as electrical transformers or electric motors submersed in oil. It should be ascertained in such cases that the lubricant's breakdown voltage is suitable. For oil circulation systems used in ATEX zones, electrostatic discharges should be avoided if the oil used has low conductivity.
No, biodegradable oils are used to reduce the impact on the environment. Any spillage of lubricant into the environment must be cleaned up as quickly as possible whether the oil is biodegradable or not. The use of bio-lubricants is currently the best alternative but does not legitimate irresponsible behavior.
The concept of biodegradability:
The term "biodegradable" denotes a product's ability to be broken down by natural organisms (bacteria, algae, mushrooms) into non-hazardous products (water, CO2) that can then be recycled by nature itself. The term "bio" also refers to a product's very low eco-toxicity levels as far as living organisms are concerned (measured by tests on algae, fish and daphnia). However, just because a product carries this label does not mean that it can be deliberately discharged into the environment. The term only guarantees that the negative effects on the environment will be kept to a minimum in the event of lost lubrication or accidental discharge.
The level of a lubricant's biodegradability can be measured by standard and standardized tests. The benchmark test that various eco-labels have chosen is the OECD 301 B biodegradability test.
Industrial lubricants and greases are used in food processing or packaging.
The concept of food grade lubricants or greases is directly related to protecting people's health and the economic consequences of doing so.
White oils: traditional oils which have undergone an enhanced treatment to make them as compatible as possible with the requirements associated with public health. They are extremely clear - hence the name "white oils" - and are approved by the Codex Alimentarius Commission.
Accidental contact: the technical constraints required by modern technologies, as well as the constraints associated with public health requirements have resulted in the development of NSF-H1-registered lubricants for accidental food contact (the successor to the USDA-H1 standard). These are oils and greases that are not harmful to people's health if they accidentally come into contact with foodstuffs. "Accidental" means, for example, a leak that was not detected early enough to be stopped, or accidental splashes.
Food Processing Aids: For situations when there is direct contact with foodstuffs, vegetable oils derived mainly from rape or sunflower seeds are used. These are very useful when removing biscuits from their moulds, for example: there is no way of avoiding contact with food, and so the components have to be even more carefully selected. These oils are referred to as "Food Processing Aids".
The food industry is gradually switching over to NSF-H-registered lubricants and vegetable oils.
NSF International is a US organization which is considered an authority in the profession and which serves as a world reference for registering (or not registering) products depending on their composition.
Priority to PAO oils for economical reason in wind turbine gearboxes maintenance.
The cost of maintenance operations on wind farms is a fundamental factor. The longer the life of the gearbox's oil bath, the fewer the number of oil changes needed, and so the lower the maintenance costs will be. The lubricant has to lubricate the equipment, keeping wear to a minimum over the longest period of time possible. Synthetic oils are the most suitable and it is acknowledged that - for reasons to do with compatibility between products, so in order to reduce the risks associated with mixes - oils formulated using PAO bases are the most suitable, even though they are not the best performing in terms of mechanical efficiency.
Wind turbines have specific lubrication methods due to the complex turbine designs and the unique operating conditions/environments.
Because of the difficulties associated with the altitude and the maintenance costs associated with wind turbines synthetics are preferred. Oils should be used which have been approved. Since mineral oils have limited service life, synthetic oil technologies based on PAOs have been developed. It is preferable to use products that have been specifically developed and approved for these performance levels - one property that is required in particular is protection against micro-pitting.
Synthetic PAO oil has the following specific advantages:
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Longer intervals between oil change service: up to 5 years.
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Excellent performance at very low temperatures.
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Miscibility with mineral oil.
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A new-generation mineral oil has the following specific advantages:
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Longer intervals between oil change service: up to 3 years.
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Excellent protection against corrosion, even in standardized tests in the presence of sea water and acidic water. Regular monitoring is important by carrying out an oil bath analysis every 6 months.
About the three main technologies of forming oils used in metalworking industry.
There are 3 main technologies of forming oils depending on the base oil.
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Neat/straight oils are like standard oils with a viscosity higher than 5cSt at 40°C. They are used for the easiest operations.
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Vanishing /evanescent oils are formulated with volatile solvents that evaporate during the operation only leaving the additives behind to do the job. The surface is then easier to degrease. With some products it is even possible not to degrease and move directly to post treatments. These products have a viscosity under 5 cSt and a low flash point (<150°C).They are used for the easiest operations.
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The third technology covers water-based products. The oil is diluted between 5% and 30% in water to enhance cooling properties. This is good for high-speed operations.
Main reasons to use specific oil in the process of producing and coning of textile yarns.
The textile industry is one of the largest industries worldwide and there are multiple production steps for the manufacture of textile goods. For productivity reasons, such steps have to be done at the maximum speed which is regularly increased through the evolution of techniques and machinery. However, higher speeds mean higher constraints and yarns have to be protected. Depending on their final field of application, textile products also have to fulfill specific requirements from raw materials to finished goods.Textile lubricants are therefore needed to protect the processed materials while coping with the inner requirements of their end-uses and industries.