gelificante
| 16:50 Sep 29, 2005 |
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| Portuguese to English translations [PRO] Tech/Engineering - Chemistry; Chem Sci/Eng / Additives | |||||||
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| Summary of answers provided | ||||
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| 3 +1 | gelling |
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| 5 -2 | coolant additives or coolants |
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| 1 -1 | anti-gel |
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| Discussion entries: 7 | |
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Answers
4 hrs confidence: 
peer agreement (net): -2
peer agreement (net): -2coolant additives or coolants Explanation: How to Protect your Diesel! Supplemental ***Coolant Additives ****(SCA's) are ... doses of these coolant additives on a regular basis (such as at every oil change) ... www.shopdiesel.com/index.cfm/action/coolantfaq.htm - 85k - Cached - Similar pages Parece que é isso mesmo...gellificantes no sentido de gelar..é um coolant em inglês -------------------------------------------------- Note added at 5 hrs 36 mins (2005-09-29 22:26:13 GMT) -------------------------------------------------- high percent of engine failures are related to the cooling system. With current engine technology it is just as important to sample coolant as it is to sample engine oil. Sampling coolant at regular intervals, along with engine oil analysis, provides the foundation for a preventive maintenance program for diesel-powered equipment. FINA CHECK offers a routine, low-cost package for periodic samples from the coolant system. This mini package inspects for major inconsistencies in coolant additive level, as well as ensures that minimum cold weather protection is being maintained. Further, FINA CHECK can also detect over-addition of antifreeze, a condition nearly as risky as having insufficient antifreeze. In addition, over concentration of coolant can create a condition known as “silicate drop-out’. This condition can plug lines and cause extensive damage to the cooling system that ultimately will result in major component damage. Furthermore, nearly half of the premature engines’ failures are the result of poor cooling system maintenance! Engine cooling systems must be filled and topped-off with fully formulated heavy-duty pre-charged antifreeze mixed with quality water (see below). Pre-charged antifreeze is defined as follows: v Fully formulated antifreeze meeting TCM RP 329 or RP 330 specifications (preferred). v Heavy-duty (low silicate) antifreeze meeting GM 6038-M or ASTM D4985 specifications (acceptable) and pre-charged with SCA. WATER QUALITY is extremely important if make-up water is added, or if coolant is diluted. Major engine makers recommend the following coolant make-up water specifications: v Hardness (calcium), less than 170 ppm v Chlorides, less than 40 ppm v Sulfates, less than 100 ppm v PH neutral Water exceeding any of the above specifications should not be used. Use distilled water, deionized water, or equivalent. COOLANT ANALYSIS AND RECOMMENDATIONS Diesel engine coolants should be analyzed twice a year (Fall and Spring) to prevent engine repairs. Diesel coolant systems need supplemental coolant additives unlike gasoline engines. Otherwise scale and cavitation-errosion will cause coolant leaks through the cylinder liner. Used or new coolant should be examined for supplemental coolant additives, glycol content, pH, phosphate content, silicate content, total dissolved solids, metals and chloride content. This will give a view of the quality of the coolant, its antifreeze capability, whether maintenance has used tap water instead of deionized water and the onset of corrosion. New coolant containing significant chlorine/chloride indicates recycled glycol or the presence of tap water and the source of the chloride needs to be determined immediately. Supplemental Coolant Additives (SCA): At initial fill, top-off, and coolant change-out, engine coolant should have a minimum pre-charge of 1.5 units per gallon (.4 units/liter) using Supplemental Coolant Additives (SCA) meeting TMC RP 328 specifications. Use of fully formulated coolants meeting TMC specifications and a correctly-sized service filter will result in a pre-charge of at least the required minimum 1.5 units per gallon (.4 units/liter). Failure to pre-charge and maintain SCA level will result in cylinder liner pitting. SCA Levels and actions needed: SCA of less than 1.2 units per gallon (.3 units/liter). Action: Pre-charge coolant using liquid SCA dose of 1.5 units per gallon and install service filter. SCA of 3.0 units per gallon (.3 - .8 units/liter). Action: Continue to install a service filter containing appropriate dosage of SCA or equivalent liquid SCA dosage at each engine manufacturer’s recommended oil drain interval. SCA greater than 3.0 units per gallon (.8 units/liter). Action: Do NOT install service filter or liquid dose. Test the SCA level using appropriate field test kit at each successive oil change. When SCA units drop below 3.0 units per gallon (.8 units/liter) resume changing the service filter or using the equivalent liquid SCA dosage. Glycol: Engine manufacturers recommend coolant composed of 50/50 water/glycol solutions providing enhanced freezes and boil protection. An operating range of 40% - 60% antifreeze (glycol is acceptable. Use of glycol percentages exceeding 65% may cause SCA drop-out, water pump seal leakage and engine overheating. PH: Coolant pH values have a normal range of 8.5 – 10.5* when pre-charges with nitrite/nitrate or nitrite-molybdate SCA. If pH falls below 8.0, rapid nitrite depletion may result. This will be shown as low SCA units. Continued additions of SCA into low pH coolant will have little effect on SCA units per gallon. When pH is less than 8.0, coolant should be drained and flushed*. Coolant pH exceeding 11.5 will corrode aluminum and promote scaling. Drain and flush is recommended. If no serious problems are encountered, flushing can be accomplished using tap water. Corrosion, scale, or gelation problems require use of chemical flushing agents. *Exceptions to this are coolants with benzoate or sebacate SCA with pH below 8.0. Total dissolved solids (TDS): Total Dissolved Solids are composed of the basic inhibitor chemicals, silicates, active SCAs, spent SCAs, contaminants and water compounds. Water pump seals tolerate gradual buildup of TDS until a 5% level is achieved. If water pump seal leakage occurs, coolant should be drained and flushed with tap water. Silicates: Silicates protect several metals in cooling systems. Automotive antifreeze typically contains large amounts of silicate. Use of automotive antifreeze and SCA leads to additive dropout, which causes plugging of radiators, heaters, and restricts engine coolant passages. Sudden introduction of large amounts of silicate through additions of automotive antifreeze or large doses of nitrite-borate SCA (high silicates) may cause rapid failure of water pump seals. Reports of low silicates and low water hardness in used coolants can be misleading. Both silicates and hardness compounds will precipitate out in the presence of each other. For an accurate evaluation of silicate levels, new antifreeze must be tested. Buffering agents: The function of phosphate and borate buffers is to counter acid formation. Acids are the production of thermal degradation of antifreeze. Without adequate buffers, corrosion and rapid additive depletion will occur due to reduction in pH values. The result will be cylinder liner pitting. Metals: Metals in the antifreeze indicate corrosion has occurred: Typical sources for corrosion products are: v IRON – liners, water pump, cylinder block, cylinder head v ALUMINUM – Radiator tanks, coolant elbows, piping, spacer plates, thermostat housings v COPPER – radiator, oil cooler, after cooler, heater core v LEAD – solder found in radiator, oil cooler, after cooler, heater core Coolants, cleaning and flushing chemicals containing 5 ppm or more lead are considered hazardous according to Federal Law. Disposal must be done in accordance with local, state or federal law. Chlorine/chloride content: Antifreeze rapidly degrades if chlorine or chlorides are present in the antifreeze. Chlorides in the presence of acid components are especially corrosive towards aluminum radiators. Chloride is also corrosive towards copper and other metals. Chlorine content (by ASTM D 5384) in the coolant is the first thing a warranty claim will look at. The chlorine/chloride content test is to determine the quality of unused coolant as well as whether the user is taking proper care of his coolant and keeping it under 250 ppm of chlorine (OEM requirement). Adding distilled water to coolant minimizes chloride content. Note tap water often contains about 500 ppm of chlorine. Chlorine/chloride content is high (100 ppm) if recycled antifreeze is used. ADDITIONAL INFORMATION Samples should be extracted from a freshly circulated system, particularly if new coolant is placed into service. We recommend a sample twice yearly just prior to the winter season and six months following. In North America this would usually be October/November and April/May. Standard lube containers can be utilized for coolant samples. |
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