Pumps chemical

Standard Chemical Pump. In 1961, the American National Standards Institute (ANSI) iatroduced a chemical pump standard (29), known as ANSI B73.1, that defined common pump envelope dimensions, connections for the auxiUary piping and gauges, seal chamber dimensions, parts mnout limits, and baseplate dimensions. This definition was to ensure the user of the availabiUty of iaterchangeable pumps produced by different manufacturers, as well as to provide plant designers with standard equipment. A typical ANSI chemical pump, known as of the mid-1990s as ASME B73.1M-1991, is shown ia Figure 6. 

Ease of maintenance is of increasing importance in todays economy. Chemical pump instaUations that require annual maintenance costing 2 or 3 times the original investment are not uncommon. In most cases this expense is the result of improper selection. 

Sealing tlie Centi-ifiig Chemical Pump Altliougb detailed treatment of. shaft seals is presented iu tbe subsection Sealing of Rotating Shafts, it is appropiiate to mention here tlie special problems... 

Doolin, J. H., Updating Standards for Chemical Pumps, Chemical Engineering, June 11, 1973, p. 117. 

A chemically pumped CO2 laser oscillating at 10 p was reported by GrossIn this system vibrationally excited COj molecules are produced by inelastic collisions with vibrationally excited DF which was formed by ultraviolet photolysis of a F2O-D2 mixture with a Xe flashlamp, producing free fluorine atoms which could react with Dj... 

Chemical pumps are available in a variety of materials. Metal pumps are the most widely used. Although they may be obtained in iron, bronze, and iron with bronze fittings, an increasing number of pumps of ductile-iron, steel, and nickel alloys are being used. Pumps are also available in glass, glass-lined iron, carbon, rubber, rubber-lined metal, ceramics, and a variety of plastics, such units usually being employed for special purposes. 

Sealing the Centrifugal Chemical Pump Although detailed treatment of shaft seals is presented in the subsection Sealing of... 

Double-Suction Single-Stage Pumps These pumps are used for general water-supply and circulating service and for chemical service when liquids that are noncorrosive to iron or bronze are being handled. They are available for capacities from about 5.7 mVh (25 gal/min) up to as high as 1.136 x lO" mVh (50,000 gal/min) and heads up to 304 m (1000 ft). Such units are available in iron, bronze, and iron with bronze fittings. Other materials increase the cost when they are required, a standard chemical pump is usually more economical. 

F+Ha HF- +. H AH =-139.9 kj is also exothermic and can produce energy rich HF molecules. The heat of chemical reaction is distributed in various vibrational-rotational modes to give vibrationally excited HF or HC1 in large numbers. Emission from these hot molecules can be observed in the infrared region at h 3.7 (j-m. The reaction system in which partial liberation of the heat of reaction can generate excited atoms or molecules is capable of laser action (Section 3.2.1). They are known as chemical lasers. The laser is chemically pumped, without any external source of radiation. The active molecule is born in the excited state. Laser action in these systems was first observed by Pimental and Kasper in 1965. They had termed such a system as photoexplosion laser. 

Calculate the chemical consumption by first inspecting the chemical pump settings and reading the maximum output on the pump plate. 

Chemically-Pumped Steady-State (Non-equilibrium) Systems. 

Pumps can be used for both loading and unloading nitric acid. Standard chemical pumps may be used for nitric acid concentrations up to 70% if they are made of suitable materials (for example, DIN/EN 1.4408 = UNS I 92900 (ASTM A 296 Grade C78M). Magnetically coupled, side-channel pumps made from Antinite (DIN/EN 1.4361 = UNS S 30601) or compressed-air diaphragm pumps made of PTFE/TFM composite are recommended for highly concentrated nitric acids above 70%97. 

For a cell membrane in a living animal, a very slight pressure difference will activate transport processes in the membrane, which will effectively eliminate the pressure difference. Introducing this change, there is no longer a state of equilibrium across the membrane, and other transport processes will take place. Such transport often is supported by chemical pumps, which move sodium ions from the protein phase to the aqueous phase. The simple estimation above illustrates that relatively small changes in the concentration are necessary to eliminate the osmotic pressure. In order to force PB — PA = 0, c(Na) in phase B must be reduced by 11 mmol/L, or by less than 10% of the previously determined concentration of 128 mmol/L (Gaiby and Larsen, 1995). 

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