Hydraulic fluids measurement

Viscosity is one of the most important properties of hydraulic fluids. It is a measure of a fluid s resistance to flow. A liquid such as gasoline which flows easily has a low viscosity, and a liquid such as tar which flows slowly has a high viscosity. The viscosity of a liquid is affected by changes in temperature and pressure. As the temperature of liquid increases, its viscosity decreases. That is, a liquid flows more easily when it is hot than when it is cold. The viscosity of a liquid will increase as the pressure on the liquid increases. 

Hydraulic fluids themselves cannot be measured in blood, urine, or feces, but certain chemicals in them can be measured. Aliphatic hydrocarbons, which are major components of mineral oil hydraulic fluids and polyalphaolefin hydraulic fluids, can be detected in the feces. Certain components of organophosphate ester hydraulic fluids leave the body in urine. Some of these fluids inhibit the enzyme cholinesterase. Cholinesterase activity in blood can be measured. Because many other chemicals also inhibit cholinesterase activity in blood, this test is not specific for organophosphate ester hydraulic fluids. This test is not available at most doctor s offices, but can be arranged at any hospital laboratory. See Chapters 2 and 6 for more information. 

Organophosphate Ester Hydraulic Fluids. Absorption rates of TOCP were measured in chickens after subcutaneous injection by measuring the apparent disappearance of TOCP from the site of injection with 31P NMR spectroscopy (Carrington et al. 1988). Five chickens were injected with single,... 

No NOAELs or LOAELs were identified for toxic effects in humans after inhalation exposure to organophosphate ester hydraulic fluids. Reliable NOAELs and LOAELs for acute inhalation exposure are restricted to 4-hour NOAELs for systemic effects in rats exposed to Fyrquel 220 or Durad MP280 and 4-hour LOAELs for mild lethargy in rats exposed to Durad MP280 and Fyrquel 220 (Gaworski et al. 1986). The study identifying these NOAEL and LOAEL values did not measure cholinesterase inhibition, did not allow sufficient follow-up time for the development of delayed neurotoxic effects, and used a... 

Jarvholm et al. 1986). Subtle electromyographical effects were measured in four of eight men exposed to lower levels of mineral oil hydraulic fluids for 3 months to 13 years (Jarvholm et al. 1986). Other studies regarding neurological effects in humans after exposure to mineral oil hydraulic fluids were not located. 

The physical properties important for the projected use of hydraulic fluids are viscosity, density, foaming behavior, and fire resistance. There is no generally recognized test method for measuring flammability of hydraulic fluids, although various test methods maybe utilized (Moller 1989). 

The log Kow, water solubilities, and Henry s law constants of several of the components that are present in the organophosphate ester hydraulic fluids included in this profile have been measured and are presented in Tables 3-4, 3-5, 3-8, and 3-9. In general, chemicals with low Kow (log Knw <1) tend to have high water solubilities, do not sorb to sediments, and do not bioconcentrate chemicals with high Kow tend to have low water solubilities, partition to sediments and soil, and bioconcentrate in fish (Lyman et al. 1982). Most of the values presented above are for mixtures and are the average values for all of the components in the mixture. 

The purpose of this chapter is to describe the analytical methods that are available for detecting, and/or measuring, and/or monitoring hydraulic fluids, their metabolites, and other biomarkers of exposure and effect to hydraulic fluids. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). 

Organophosphate Ester Hydraulic Fluids. The measurement of organophosphate esters in fish and human adipose tissue has been used to assess environmental contamination in several studies (Mayer et al. 1981). The methods are able to detect concentrations of 0.1 mg/kg in fish and 2.5 pg/kg in human adipose... 

It is obvious from Equation 14.14 that the most important parameter determining the volumetric air flow rate <2W is the intrinsic permeability K of soil. At this point it is important to stress the difference between water permeability (or hydraulic conductivity) k , air permeability ka, and intrinsic permeability K. In most cases, when permeability data are provided for a type of soil or geological formation, these data are based on hydraulic conductivity measurements and describe how easily the water can flow through this formation. However, the flow characteristic of a fluid depends greatly on its properties, e.g., density p and viscosity p. Equation 14.16 describes the relationship between permeability coefficient k and fluid properties p and p ... 

Elevated concentrations of the n-Cl3 to -CIH alkanes and branched-chain and cyclic analogs were measured in a building having a history of air quality complaints the source was found to be volatilization from hydraulic fluids used in the building elevators (Weschler et al., 1990). 

According to the 1981-83 National Occupational Exposure Survey, as many as 15 600 workers in the United States were potentially exposed to di(2-ethylhexyl) adipate (NOES, 1999). Occupational exposure may occur through inhalation, mainly as an aerosol, during its manufacture and its use, particularly as a plasticizer of PVC films and in other materials used in food packaging such as adhesives, cellophane and hydroxy ethyl cellulose films. Exposure may also occur during the manufacture of rubber products, nonferrous wire, cosmetics, lubricants and hydraulic fluids (Opresko, 1984). No measurements of di(2-ethylhexyl) adipate exposure in manufacturing and processing industries are available. 

Ottewill and co-workers106,200 have used a compression method to measure the double-layer repulsion between the plate-like particles of sodium montmorillonite. This is a particularly suitable system for such studies, since the particles are sufficiently thin (c. 1 nm) for van der Waals forces to be unimportant and surface roughness is not a problem. The dispersion was confined between a semipermeable filter and an impermeable elastic membrane and an external pressure was applied via a hydraulic fluid so that the volume concentration of particles and, hence, the distance of separation between the particles could be measured as a function of applied pressure. 

Murray [91] has described a gas chromatographic method for the determination in water of triarylphosphate esters (lmol S-140, tricresyl phosphate, cresol phosphate). These substances are used commercially as lubricant oil and plastic additives, hydraulic fluids and plasticisers. The method involves extraction from the samples, hydrolysis and measurement of the individual phenols by gas chromatography as the trimethylsilyl derivatives. The lower detection limit was about 3ppm. 

This profile covers total petroleum hydrocarbons (TPH), which is defined as the measurable amount of petroleum-based hydrocarbon in an environmental medium (Chapter 2). TPH is measured as the total quantity of hydrocarbons without identification of individual constituents. Sources of TPH contamination in the environment range from crude oil, to fuels such as gasoline and kerosene, to solvents, to mineral-based crankcase oil and mineral-based hydraulic fluids. These products contain not only a large number and variety of petroleum hydrocarbons, but also other chemicals that, strictly speaking, are not the subject of this profile, such as non-hydrocarbon additives and contaminants. The TPH issue is further complicated by the number of petroleum-derived hydrocarbons that have been identified—more than 250—and the variability in composition of crude oils and petroleum products (see Section 3.2 and Appendices D and E for details). 

The Brool eld viscosity test measures the low-temperature viscosity of gear oils and hydraulic fluids under low shear conditions. Brookfield viscosities are measured in centipoise units using a motor-driven spindle immersed in the cooled oil sample, ASTM D2983. 

Common antioxidants in hydraulic fluids are measured over the region 3700-3595 cm The left baseline, high wave number side, is taken as the minima in the region of 4000-3820 cm and a right baseline, low wave number side, as the minima in the region of 2200-1800 cm For polyol ester fluids, antioxidants are measured over the region of 3400-3320 cm using the same baseline correction. 

Fig. 3.17 The Paris-Edinburgh V4 press it has a nominal working capacity of 250 tonnes (2.5 MN) (1) sample and gasket arrangement (see Fig. 3.16), (2,3) anvil and seat binding rings, (4) breech, (5) upper platen, (6) B4C neutron collimator, (7) piston, (8) hole for transmission measurements, (9) O-rings, and (10) hydraulic-fluid inlet. The dimensions are in millimetres.

Use a common, semiportable unit to generate and measure pressures and to deliver them to different pressure chambers by a hydrostatic connection. For reliability, use oil for the hydraulic fluid in this unit. 

Osterberg (1984) developed a method that reduces the cost of conducting high capacity static load tests, in particular for the drilled shafts, as shown in Figure 11.6. Once the concrete is in place, the operator pumps hydraulic fluid into the jack and keeps track of both pressure and volume. The jack expands and pushes up on the shaft. A dial gauge measures this movement, from which a plot of side friction capacity versus axial movement can be obtained. The devise also includes a telltale rod that extends from the bottom of the pancake jack to the ground surface. It measures the downward movement at the bottom, and thus produces a plot of toe-bearing pressure versus axial movement. 

What was the hydraulic fluid used in the mechanism and were any special measures taken to prevent leakage into the reactor ... 

The hydraulic fluid was Castrol Hyspin 40AUS10 which had been tested for air oxidation rates of core graphite and found to have negligible effect. No particular measures were taken to prevent leakage in the reactor other than checking prior to the entry. 

The major attraction of pneumatic systems for prosthetics applications is their inherent compliance, which tends to give these systems a very natural look and feel. While pneumatic systems did find some measure of success in prosthetics, hydraulic systems did not. Hydraulics tended to be messy, with hydraulic units leaking hydraulic fluid. In addition, a fluid reservoir and fluid are required, adding to the total weight of the mechanism. 

Cutting manufacturing costs was a crucial factor in the decision by Fokker to choose PEEK instead of metal alloy for vital components in the F100. Other important factors were low density, resistance to hydraulic fluids, low flammability, and excellent mechanical properties. The support bar measures 400 X 1(K) X 300 mm and weighs 1.0 kg, making it one of the largest injection mouldings so far made in Victrex PEEK, and a considerable achievement for the moulders, AGF, BV. 

Friction and wear were measured using the Penn State sequential four-ball test. The sequential test was developed to evaluate hydraulic fluids [4-6]. This test operates in the boundary lubrication regime. Test variables included time, load, speed, and temperature. Both torque (friction) and wear were measured. The sequential test con-... 

Leakage in fuel and hydraulic fluid systems of aircraft are viewed extremely seriously. Safety is a compelling factor that demands high quality from ruhher seals to he used in aircraft components. Hence, aircraft seals are manufactured with extra precision and extremely strict quality control measures for materials and their processing. Strict adherence to the specification of raw materials, processing methods, testing procedures, and dimensional standards are required. 

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