【正文】 C). 9. Repeat Step 8 for maximum continuous and minimum continuous viscosities of the pump (brown lines, Figure 3). The area between the minimum and maximum temperatures is the minimum and maximum allowable operating temperature of the pump for the selected lubricant product. 10. Find the normal operating temperature of the pump on the chart using the heat gun scan done in Step 2. If the value is within the minimum and maximum temperatures as outlined on the chart, the fluid is suitable for use in the system. If it is not, you must change the fluid to a higher or lower viscosity grade accordingly. As shown in the chart, the normal operating conditions of the pump are out of the suitable range (brown area, Figure 3) for our particular lubricant and will have to be changed. Figure 3 Also, observe the following hydraulic fluid management practices. ? Implement a procedure for labeling all ining lubricants and tagging all reservoirs. This will minimize crosscontamination and assure that critical performance requirements are met. ? Use a FirstInFirstOut (FIFO) method in your lubricant storage facility. A properly executed FIFO system reduces confusion and storageinduced lubricant failure. Hydraulic systems are plicated fluidbased systems for transferring energy and converting that energy into useful work. Successful hydraulic operations require the careful selection of hydraulic fluids that meet the system demands. Viscosity selection is central to a correct fluid selection. There are other important parameters to consider as well, including viscosity index, wear resistance and oxidation resistance. 。C as published by your lubricant manufacturer. When you find the corresponding line, make a small mark at the intersection of the two lines (red lines, Figure 3). 6. Repeat Step 5 for the lubricant properties at 100186。C line. At the 40186。C and cSt at 100186。C and 100186。O), anticorrosion agents, demulsifies, antiwar (AW) and extreme pressure (EP) agents, VI improvers and defoamants. Mineralbased fluids offer a lowcost, high quality, readily available selection. 2. Waterbased fluids are used for fireresistance due to their highwater content. They are available as oilinwater emulsions, waterinoil (invert) emulsions and water glycol blends. Waterbased fluids can provide suitable lubrication characteristics but need to be monitored closely to avoid problems. Because waterbased fluids are used in applications when fire resistance is needed, these systems and the atmosphere around the systems can be hot. Elevated temperatures cause the water in the fluids to evaporate, which causes the viscosity to rise. Occasionally, distilled water will have to be added to the system to correct the balance of the fluid. Whenever these fluids are used, several system ponents must be checked for patibility, including pumps, filters, plumbing, fittings and seal materials. Waterbased fluids can be more expensive than conventional petroleumbased fluids and have other disadvantages (for example, lower wear resistance) that must be weighed against the advantage of fireresistance. 3. Synthetic fluids are manmade lubricants and many offer excellent lubrication characteristics in highpressure and high temperature systems. Some of the advantages of synthetic fluids may include fireresistance (phosphate esters), lower friction, natural detergency (anic esters and esterenhanced synthesized hydrocarbon fluids) and thermal stability. The disadvantage to these types of fluids is that they are usually more expensive than conventional fluids, they may be slightly toxic and require special disposal, and they are often not patible with standard seal materials. Fluid Properties When choosing a hydraulic fluid, consider the following characteristics: viscosity, viscosity index, oxidation stability and wear resistance. These characte