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By T. W. Oshnock

Pulverized coal (PC) and other injectants can be injected into the blowpipes of a blast furnace to decrease coke requirements. Throughout the history of blast-furnace development, there have been many attempts at injecting PC. In the 1960's a more serious effort was made to improve pulverized coal injection (PCI) technology. However, because of the additional capital requirements and the projected near-term inexpensive cost of other injectants, very few PC1 systems were installed. When the second oil crisis occurred around 1979, the shortage and high cost of fuel oil caused blast-furnace operators to operate without oil injection. It was soon discovered that blast- furnace operation without oil was not as smooth or efficient. Experiments with PC1 quickly showed that coal was a good replacement for oil which resulted in the rapid application of PC1 in both Europe and Japan. As a result, PC1 technology for blast-furnace operation has progressed rapidly during the 1980's. This paper will describe the worldwide status of PCI, characteristics of different PC1 systems, the effect of PC1 on blast-furnace process parameters, and the economic effects of using PCI. Results from the USS Blast-Furnace Thermochemical Projection Model comparing the effects of different coal properties and the effects of other tuyere injectants such as oil and natural gas will also be described.

Jan 1, 1988

By André Oliveira

The present paper describes state-of-the-art Pulverized Coal Injection technology with focus to Dynamic Distribution guaranteeing highest accuracy on equal distribution and being thus one of the key factors enabling constantly highest injection rates. As an alternative to the construction of a new plant, existing plants may be modernized and upgraded to latest technology. Two recent examples are presented. As a conclusion, two case studies of return on investment are showing that the PCI technology, both for new facilities as well as for upgrades, is very profitable and mandatory for high blast furnace operation effectiveness.

Aug 17, 2017

By John C. Nigro

The Bureau of Mines is investigating the use of pulverized coal as a fuel for iron ore pelletizing to determine its effectiveness as a substitute for natural gas and oil. Experimental data illustrates the application of both a gun-type suspension burner and a cyclonic-type slagging burner to a grate-kiln pelletizing unit. In addition, experimentation with a cyclonic fired external combustion chamber for possible adaptation to a shaft or straight grate pelletizing furnace is discussed. The tests were conducted in the Bureau of Mines Twin Cities Metallurgy Research Center's pilot plant with high rank bituminous coals from Kentucky and Colorado and low rank subbituminous coals and lignites from Montana, Wyoming and North Dakota. Although combustion was excellent with the suspension burner, the low ash fusibility temperature coals and lignites caused some kiln ringing and accretion buildup in the grate kiln transfer section which were not encountered when firing with the high ash fusibility temperature Kentucky coal. Pellet contamination by coal ash was not deemed substantial. Problems with the cyclonic burner and external refractory combustion chamber centered around (a) maintaining complete combustion of the coal within the burner, (b) molten slag attack on the lower refractory chamber resulting in erosion of the lining and increased slag viscosities, and (c) freeze-up of the slag tap hole.

Jan 1, 1977

Brief descriptions of several types of unit pulverizeI' are given and the functioning of the components that crush, carry, dry and classify the coal is considered. A distinction is drawn between pulverizers which crush particle beds and those .operating by free-crushing. The overall performance of pulverijlers is considered in terms of correlations between mill variables, coal grindability, abrasiveness, moisture and particle size. Brief discussioiJ. of the influence of pulverized fuel quality on boiler operation and of pulverizing costs concludes the paper.INTRODUCTIONModern coal pulverizers function as carriers of materials and as crushers, as dryers and as size classification machines and, thus, the unit pulverizer comprises. several components that normally function as separate apparatus. The controls of the unit pulverizer must have sufficient flexibility to accommodate rapid variations of boiler load or coal quality. Further, the machine must be robust, yet easy to maintain preferably at annual intervals-so that maintenance costs are small (for coal is a relatively cheap material). Usually, the full load of a modern pulverized-fuel fired boiler can be raised with one pulverizer off-line. All coals, from anthracites to brown coal, may be prepared as pulverized fuel (hereafter P.F.) .Each pulverizer of a direct-fired boiler has, broadly, to supply the burners with coal powdered so that about 80 per cent passes a 200 B.S. sieve and only a small proportion, less than about 10 per cent, remains on the 100 B.S. sieve. The classification processes must prevent any appreciable proportion of coarse particles in the P.F. and yet not return excessive proportions of "finished" fines. The quality of the P.F. should not vary greatly with output rates which may be anywhere between the maximum rate and one quarter ofthe maximum. The suspension of P.F. in the primary air...

Jan 1, 1957

By James A. Barr

PUMICE and pumice are varieties of volcanic ejecta formed from lavas of the more silicic types. Chemical analyses of pumice, pumicite and perlite, from which synthetic pumice is now produced, will generally fall within the limits 65 to 75 pct silica, 9 to 20 pct alumina, less than 8 pct combined alkalies (sodium and potassium oxides), less than 3 pct calcium and magnesium oxide, less than 3 pct iron oxide, with smaller amounts of manganese, titanium, phosphorus and other oxides. Perlite is characterized chemically by having, in addition to the percentages of oxides given above, as high as 6 pct combined water. PROPERTIES Pumice is a natural silicic foam glass produced by volcanic eruptions. The molten glass foam, upon rapid cooling, trapped the steam and volcanic gases that caused it to remain extremely porous and vesicular in structure. Pumice is found in the form of large lumps several cubic feet in volume and also in grains only a few millimeters in diameter. Chemically, pumicite is of the same range of composition as pumice. The distinction between pumice and pumicite is one of particle size; the coarser materials are pumice; the fine particles, an appreciable percentage of which is in the range of 100 to 325-mesh or finer, are pumicite. If the erupting volcano ejects a silicic lava containing much gas and water vapor, the sudden release of pressure tends to free the gas. The viscosity of the lava, its rate of cooling and the amount of gas evolved, all have part in determining the degree of expansion of the glassy particles and the fineness of the vesicle. If the lava is of the correct viscosity and there is not too much gas, a pumice may be formed. Large amounts of gas may cause complete disruption into pumicite.30 In 1916, Barbour gave the name "pumicite" to the volcanic ash of Nebraska and since then the name has been widely used in industrial circles for the finer-grained commercial varieties. The glass of pumice and pumicite is transparent and colorless. It

Jan 1, 1949

By Gordon C. ‘Bud’ Presley

The pumice and pumicite review arrived too late for the June issue. Estimated domestic production of pumice and pumicite in 1992 was up compared with 1991, according to US Bureau of Mines statistics. The Bureau estimate of domestic production of 400 kt (440,000 st) for 1991 turned out to be 401 kt (442,000 st) of actual production, the lowest since 1989. In 1992, the estimated the value of pumice and pumicite sold or used in the United States was $11.6 million, up only $200,000 from the 1991 value. There was an increase in the mine, or mill, average price from the five-year low of $11.44/t ($10.37/st) in 1986 to $26.42/t ($23.96/st) in 1992. Estimated tonnage produced in 1992 was 439 kt (484,000 st). Apparent domestic consumption was 642 kt (707,000 st), up 135 kt (149,000 st) from 1991. Imports for consumption were estimated to be 215 kt (237,000 st) last year. Domestic production supplied 68% of the demand in 1992, with net imports supplying the remaining 32%. This compares with domestic production sup¬plying 53% and net imports supplying 47% of the apparent consumption in 1988. Exports were about 900 t/a (1000 stpy) for the period 1984 to 1988. In 1989, exports rose sevenfold to 7 kt (7700 st) and to 20 kt (22,000 st) in 1990. The Bureau of Mines reported that the amount of pumice and pumicite exported in 1992 was 12 kt (13,200 st). It is assumed that these exports were from the Pacific Coast because imports, mainly from Greece, continued to be a market factor on the East Coast and the Gulf Coast States in the United States.

Jan 1, 1993

By Ronald P. Geitgey

Pumice and volcanic cinder are volcanic rocks characterized by a cellular structure. They are formed as gases (primarily water) dissolved in molten rock, or magma, exsolve to generate a froth that cools and solidifies into rigid foam. The cells or bubbles are referred to as vesicles and they range in size from a few thousandth of a millimeter to several centimeters. Due to their vesicular character, both pumice and cinder have lower density and higher porosity than most other rock types, and, as the vesicle walls are broken, sharp cutting edges are continually generated. These properties are the basis for their commercial value as lightweight aggregates, insulators, absorbents, and abrasives. There is a certain imprecision in the terminology applied to volcanic products, reflecting to varying degrees the diversity of volcanic rocks, the relative youth of volcanology as a distinct field of study, and customs and practices of commercial trade. In general terms, pumice is light colored (white, gray, pink, pale yellow, or brown) and highly vesicular, usually with vesicle walls that are visibly glassy. Many pumice fragments are light enough to float on water. Pumice is readily cut by steel tools and some can be crushed by hand. Individual pumice fragments may range from 1 or 2 m in one dimension to c1 mm. Commercially, finer fragments are called pumicite or volcanic ash. In volcanology the term ash refers to any fragment c2 mm in size regardless of its composition. Cinder, or scoria, is dark colored (black, red, brown) with thick vesicle walls that appear dull or stony and that may exhibit iridescence. Cinder typically is heavier than pumice and has a higher crushing strength. In volcanology the term scoria refers to dark vesicular material throughout a wide size range while it is common commercial practice to use scoria for larger fragments (usually greater than 2.5 cm) and cinder for smaller fragments. GEOLOGY Composition and Physical Characteristics Most pumice is silicic ranging from 60 to 70% SiO2, that is, dacitic to rhyolitic in composition. Pumice of less silicic composition, including basaltic, occurs but it is less common and does not have extensive commercial use. Scoria and cinder are typically basaltic to andesitic with approximately 50 to 60% SiO2. Pumice and cinder may contain phenocrysts of feldspars and various ferromagnesian minerals that crystallized in the magma prior to eruption. Fragments of rock through which the magma has passed may be entrained in the melt and wall rock may be fragmented and admixed during an explosive eruption. Some scoria particles have lithic fragment cores. Phenocrysts and lithic fragments are relatively unimportant in cinder end uses but their presence may be detrimental in certain pumice products. Pumice typically has vesicles <1 mm in size separated by thin walls. Vesicle shapes include irregular, spherical, elliptical, and elongate to the point of being tubular with a silky appearance (Fig. 1). In some pumices, the vesicles are interconnected making the fragments permeable and highly absorbent; in others the vesicles are isolated forming a highly porous but very impermeable pumice. Floating masses of pumice fragments from the eruption of Krakatoa in 1883 were reported in the Indian Ocean for up to two years after the eruption. Vesicles in cinder are larger and range from spherical to highly irregular in shape with much thicker walls and abundant interconnections. Scoria and cinder are typically heavier, porous, and do not float. Density and hardness of pumice must be expressed precisely to avoid confusion. Density may refer to the glass itself, the apparent density of the vesicular pumice particle, or the bulk density of pumice in a deposit or in a product. Pumice glass has a specific gravity of 2.5 or more depending on its composition. Pumice fragments typically have a specific gravity of 4.0 and so will float on water, at least until enough vesicles are saturated to cause them to sink. Expressed as density, pumice fragments typically weigh less than 1 g/cm3. Depending on moisture content, particle density, and particle size distribution, the bulk density of pumice typically ranges from 500 to 700 kg/m3. Typical bulk densities of cinder range from 700 to 900 kg/m3 for material used as lightweight aggregate while the bulk density of cinder used for highways and railroad ballast may be considerably higher. Hardness in pumice may refer to the glass vesicle walls, possibly including crystals or lithic fragments, or to the apparent hardness of the particle as a whole, which is more a measure of the strength of the vesicle structure. Pumice glass typically has a Mohs hardness of 5 to 5.5. A pumice particle may have a much lower apparent hardness and be easily cut with a knife or steel saw because the vesicle walls break readily. Pumice and cinder are primarily pyroclastic deposits formed as fragmental products of volcanic eruptions. Several classification - systems differing in various details have been proposed for pyroclasts and pyroclastic deposits based on particle size (Fisher, 1961, Schmid, 1981, Cas and Wright, 1988). Generally, particles >64 mm are referred to as blocks or bombs depending on their shape. Particles between 64 mm and 2 mm (4 mm in some schemes) are called lapilli and smaller particles are called ash. These names may be modified by compositional terms, for example pumice lapilli or scoria lapilli. Most commercial deposits are composed of fragments in the lapilli size range. In the United States, pumice fragments having one dimension of 5 cm or more are legally defined as block pumice. The procedures for acquiring pumice from federal land are determined in part by this definition and are described in a later section.

Jan 1, 1994

By Gregg Wilkerson

The Blind Springs Hill pumice beds are located 5 miles southwest of Benton, California in the foothills between the Benton Mountain Range and Blind Springs Valley. The best exposures of the pumice are in an area 0.75 miles west of Blind Springs Hill. The pumice is Quaternary ejecta material which came from the rhyolitic volcanoes in the Glass Mountain-Volcanic Tablelands area of Mono County. The pumice beds occur in two distinct layers separated by an unconformity. The upper layer is 0 to 11 feet thick and consists of coarse subangular pumice fragments, some of which are over 1.75 inches in diameter. The lower bed is medium to coarse grained with subangular fragments up to 1.0 inch. The lower bed is 0 to 9 feet thick. Overburden at the Blind Springs Hill deposit varies from 0 to 15 feet. There are approximately 1 million cubic yards of material in the deposit that can be mined. The size distribution in the deposit is mostly fine with only 10.6% of the pumice fragments being over 0.5 inch in diameter, the minimum size needed for stone-wash or acid-wash applications. Suitability of pumice for the textile industry is quantified by standard 15-minute abrasion and absorption tests. In the Blind Springs Hill deposit, the plus 0.5 inch fraction has an abrasion loss of 33% which is too high for stone-wash application but it has an absorption capacity of 36% which makes it suitable for acid-wash applications in the textile industry. The abrasion and absorption properties of this deposit are within the range of those which have been measured for other pumice deposits within the United States.

Jan 1, 1995

By N. V. Peterson, R. S. Mason

Pumice, pumicite, and cinders are all products of explosive volcanic eruptions. Pumice and pumicite are produced by the violent expansion of dissolved gases in a viscous silicic lava such as rhyolite or dacite. Pumice is a light-colored, cellular, almost frothy rock made up of glass-walled bubble casts. It may occur as coherent, massive blocks composed of highly vesicular glassy lava in either a flow or vent filling, or it may be more or less fragmented by violent eruption. Pumicite has the same origin, chemical composition, and glassy structure as pumice differing only in particle size. Particles less than 4 mm in diam are designated pumicite. Pumice is usually found relatively close to the vent from which it was erupted while pumicite may be carried by winds for great distances before settling as an accumulation of fine-grained ash or tuffaceous sediment. Volcanic cinders are the reddish to black vesicular fragments that pile up during explosive eruptions of volcanoes of basaltic composition. Most deposits of cinders occur as cones or mounds of stratified fragments that range in size from a fraction of an inch to several inches in diameter. Individual cones or mounds of cinders may be several hundreds of feet in diameter and as much as 500 ft high. Properties The properties that make pumice and pumicite useful in industrial applications include: low-bulk density, good heat and sound insulating properties, and excellent abrasive capability. Cinders, even though less cellular and somewhat heavier, also have a variety of industrial uses. Uses The main use of pumice and cinders continues to be in the construction industry as road-surfacing material, railroad ballast, building block aggregate, in lightweight structural concrete, and as plaster aggregate. Both pumice and pumicite continue to be used as abrasives for polishing glass, metal, leather, stone, and wood. Some scouring powders and soaps also contain pumicite. Minor uses include fillers, absorbents, carriers for insecticides, catalyst carriers, filters, and soil conditioners. Pumicite is also used in sizable quantities as a pozzolanic additive in monolithic concrete where it increases the workability, strength, and durability of the concrete and reduces the heat of hydration. Volcanic cinders are generally denser and more coarsely cellular than most pumice. Markets for cinders include aggregate for road construction and surfacing and in lightweight concretes, particularly blocks. Some producers having access to both pumice and cinders offer a variety of blends of the two materials to block manufacturers. Most pumice deposits are unconsolidated and usually have a minimum of overburden. Mining is by open pit and can be easily carried out with conventional loading equipment. Sometimes air-drying precedes hauling to a crushing and screening plant which yields the size product desired. Multiple bins at railroad hauling facilities permit blending if desired. Pumice for abrasive use may require more sophisticated processing by fine grinding and air classification before being bagged for market. Block pumice in economic quantity and quality is limited to a few geologically young

Jan 1, 1975

By N. V. Peterson, R. S. Mason

The violent explosion of Mount St. Helens in the state of Washington on May 18, 1980 showered volcanic ash over vast areas of the Northwest. It was another eruptive episode in a long history of similar occurrences in the region, which extends from Canada to California and reaches several hundred miles inland from the Pacific Ocean. Pumice, pumicite, and cinders are products of explosive volcanic eruptions. Pumice and pumicite are produced by the violent expansion of dissolved gases in a viscous silicic lava such as rhyolite or dacite. Scoria is the mafic counterpart of pumice. Pumice is a light-colored, cellular, almost frothy rock made up of glass-walled bubble casts. It may occur as coherent, massive blocks composed of highly vesicular glassy lava in either a flow or vent filling, or it may be more or less fragmented by violent eruption. Pumicite, the diminutive of pumice, has the same origin, chemical composition, and glassy structure, differing only in particle size. Particles less than 0.16 in. in diam are designated pumicite. Pumice usually is found relatively close to the vent from which it was expelled, while pumicite may be carried by winds for great distances before settling as an accumulation of fine-grained ash or tuffaceous sediment. Mount St. Helens lofted an estimated 5 billion cu yd of ash and pumicite. The volcano, unlike most of the High Cascade peaks, is composed largely of dacitic material with only minor amounts of andesite and basalt. Volcanic cinders are the reddish to black vesicular fragments which pile up during explosive eruptions of volcanoes of basaltic composition. Most cinder deposits occur as cones or mounds of stratified fragments ranging from a fraction of an inch to several inches in diameter. Individual cones or mounds may be several hundred feet in diameter and up to 500 ft high. Properties and Uses Low bulk density, good heat and sound insulating properties, and excellent abrasive capabilities make pumice and pumicite useful in industrial applications. Cinders, though less cellular and somewhat heavier, also have a variety of industrial uses. The main use of pumice and cinders continues to be in the construction industry as road-surfacing material, railroad ballast, and building block aggregate. Pumicite is used in sizable quantities as a pozzolanic additive to monolithic concrete where it increases workability, strength, and durability of the concrete and reduces the heat of hydration. Volcanic cinders generally are denser and more coarsely cellular than most pumice. Markets for cinders include aggregate for road construction and surfacing and use in lightweight concretes, particularly blocks. Some producers having access to both pumice and cinders offer a variety of blends of the two materials to block manufacturers. Table I lists the principal applications of industrial pumice. Tables 2 and 3 show US sales and uses of volcanic products. Most pumice deposits are unconsolidated and usually have a minimum of overburden. Mining is by open pit and can be easily carried out with conventional loading equipment. Sometimes air drying precedes hauling to a crushing and screening plant which yields the size product desired. Multiple bins at railroad hauling facilities permit blending if desired. Pumice for abrasive use may require more sophisticated processing by fine grinding and air classification before being bagged for market.

Jan 1, 1983

The design/optimization of the pump and cyclones to maximize grinding circuit efficiency first requires a concise understanding of, and clearly defined specifications for, desired grinding circuit performance. Subsequently, the pump and cyclone performances that provide the desired grinding circuit performance can be defined. Once the performance requirements of each process unit are determined, selection of physical equipment parameters that will deliver those performances can be carried out. The Functional Performance Equation shows that there are two distinct efficiencies in closed circuit ball milling. One of these, ?Circuit Classification System Efficiency? (CSE), is the fraction of ?coarse? material inside the ball mill upon which grinding energy is deliberately expended, versus the remaining fraction of ?fines? or finished size material inside the mill, upon which grinding energy is wasted (on over-grinding). The role of the pump and cyclones is to maximize CSE, which is the desired grinding circuit performance. The obtainable, target CSE for any given circuit can be estimated, for example by referring to a plant data base of CSE?s. Design/optimization guidelines then allow us to specify the pump and cyclone performances that will achieve the target CSE. This paper outlines the step-by-step, systematic method of pump and cyclone selection which maximizes CSE. Numerous examples of its successful application are provided.

Jan 1, 2011

By Robert E. McIvor

"The design/optimization of the pump and cyclones to maximize grinding circuit efficiency first requires a concise understanding of, and clearly defined specifications for, desired grinding circuit performance. Subsequently, the pump and cyclone performances that provide the desired grinding circuit performance can be defined. Once the performance requirements of each process unit are determined, selection of physical equipment parameters that will deliver those performances can be carried out.The Functional Performance Equation shows that there are two distinct efficiencies in closed circuit ball milling. One of these, “Circuit Classification System Efficiency” (CSE), is the fraction of “coarse” material inside the ball mill upon which grinding energy is deliberately expended, versus the remaining fraction of “fines” or finished size material inside the mill, upon which grinding energy is wasted (on over-grinding). The role of the pump and cyclones is to maximize CSE, which is the desired grinding circuit performance. The obtainable target CSE for any given circuit can be estimated, for example, by referring to a plant data base of CSE’s. Design/optimization guidelines then allow us to specify the pump and cyclone performances that will achieve the target CSE.This paper outlines the step-by-step, systematic method of pump and cyclone selection which maximizes CSE. Numerous examples of its successful application are provided.THE FUNCTIONAL PERFORMANCE EQUATIONObservation of the feed and product size distributions going into and discharging from the mill in grinding circuits with low versus high circulating load ratios initially led to the definition of “Circuit Classification System Efficiency” (or CSE, McIvor, 1988a), and subsequently the discovery of the Functional Performance Equation (McIvor, 1988b; McIvor et al, 1992). The CSE is the fraction or percentage of “coarse” (usually in reference to the plus P80) size material inside the mill, versus “fines” or product size material finer than the circuit P80. It can be readily calculated by taking the average of the percentage of said coarse material in the mill feed and mill discharge streams. As this also represents the percentage of the mill energy expended on targeted, coarse size material, it is directly proportional to overall grinding circuit efficiency and production rate. This is all clearly expressed in the Functional Performance Equation for ball milling circuits, for which the derivation has often been presented (e.g. McIvor, 2006)."

Jan 1, 2011

A 36-year-old A-S-H pump, manufactured to designs dating back to 1936, was recently presented to the Gold Mine Museum by Envirotech. The pump, a B-frame three-piece rubber-lined Hydroseal unit, was supplied by Envirotech&apos;s predecessor company, Denver Machinery, and was installed by South Roodepoort Main Reef Areas Limited on 22nd March, 1948. Metals, materials, manufacturing The 37th Annual Conference of the Australasian Institute of Metals will be held in Ballarat (Australia) from 13th to 17th May, 1985. 1985is the Sesquicentennial year of Victoria, and for the first time the historic City of Ballarat has been chosen as the venue for an Australasian Institute of Metals congress. Steel rolling Conferences on steel rolling, sponsored by The Iron and Steel Institute of Japan (ISH), and supported by iron and steel institutes in many countries of the world, have been held since 1980. The first conference was held in Tokyo in 1980, sponsored by The Iron and Steel Institute of Japan.

Jan 1, 1984

By Ralph van Rijswick, Erik Vlot

"Anglo American operates 18 Weir GEHO piston diaphragm pumps (PD) in the two pump stations of the 52-km (32-mile) long Minas Rio iron ore concentrate pipeline. The pipeline is designed to transport 26.5 Mt/a (29.2 million stpy) of concentrate from the mine to the export terminal at the coast.During the commissioning of the pipeline in the fall of 2014, high pressure pulsation levels were experienced, with peak-to-peak levels as high as 20 bar. Based on pressure readings it was concluded that hydraulic resonances were present in the system, which were excited by the third and sixth harmonic of the flow pulsation generated by the pumps.Based on this observation, Weir Minerals Netherlands, manufacturer of GEHO PD slurry pumps, recommended installing a phase shift controller that controls the phase shift between the crankshafts of the individual pumps, thereby minimizing the effect of the hydraulic resonances.GEHO piston diaphragm pumps and pressure pulsation analysisPiston diaphragm pumps are used worldwide to transport abrasive and/or aggressive slurries against high discharge pressures in the mining, mineral processing and power industries. The basic operating principle of a piston diaphragm pump is shown in Fig. 1.A crankshaft is driven by an external electric motor via a gearbox. The crank mechanism transfers the rotating motion of the crankshaft into a reciprocating motion of the piston. The piston displaces a hydraulic fluid, called the propeling liquid, which displaces an elastic rubber diaphragm. When the piston moves to the right, the pressure in the pump chamber drops below the suction pressure and the nonreturn valve on the suction side will open, allowing the pumped fluid to flow into the pump chamber. When the piston moves to the left, the fluid is compressed, and when the pump chamber pressure rises above the pipeline pressure, the nonreturn valve on the discharge side will open allowing a displacement of fluid into the discharge line. The main objective of the diaphragm is to isolate the piston and the drive mechanism from the abrasive and/or aggressive fluid and create a hermetic seal between the pumped fluid and the ambient environment. Piston diaphragm pumps as shown in Fig. 1 are among the largest positive displacement pumps in the world and have been produced with stroke volumes of up to 100 L (26 gal) per pump chamber for flow rates up to 800 m3/h, discharge pressures up to 250 bar and hydraulic outputs over 2 MW per unit (van Rijswick et al., 2010)."

Jan 9, 2017

By Tom Watts

This paper will focus on the design, manufacture and use of pump safety systems on MMUs (Mobile Manufacturing Units – Bulk Trucks) with progressive cavity pumps. The practice of pumping bulk blasting agents is highly regulated and the explosives manufactures have done an excellent job of hazard and operability studies allowing criteria to be established for the safe pumping.

Jan 1, 2009

By Hans Perlid

In the handling of emulsion explosives pumping is a key operation. A number of serious accidents has shown that pumping can be a risky operation and should be care&lIy considered and investigated. This is the background behind a series of pump tests carried out by NTTRO NOBEL.

Jan 1, 1996

By Hans Perlid

In the handling of emulsion explosives pumping is a key operation. A number of serious accidents has shown that pumping can be a risky operation and should be carefully considered and investigated. This is the background behind a series of pump tests carried out by NITRO NOBEL.

Jan 1, 1996

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Jan 1, 1938

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Jan 1, 1938

By Scott G. Britton

Traditionally, water removal has taken a backseat to many other coal mining functions. However, it is a vital part of the total mine support system. In many US coal mines, more tons of water are removed each year than tons of coal. An excellent discussion of general drainage characteristics can be found in Chapter 8 of Elements of Practical Coal Mining, published by SME-AIME. This chapter is organized into three major sections. These are: designing effective drainage systems; constructing the main mine pumping station (static system); and constructing a portable pumping station (dynamic system). Each topic presents a separate discussion of the elements a construction foreman or engineer should consider for effective installation and operation of the mine drainage system. In addition, a list of pumping equipment manufacturers is available to interested persons and follows these sections.

Jan 1, 1983