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Manufacturing building asbestos-cement products

Manufacturing building asbestos-cement products

Asbestos-Cement Shingles. The Asbestos Shingle, Slate, and Sheathing Company touted the advantages of their shingles with depictions of successful installations in their promotional catalog and price list. Dodge Corporation, Manufacturers of asbestos-cement shingles and other asbestos building products appealed to architects and builders directly with extensive advertising campaigns. Johns-Manville promoted the direct application of their asbestos-cement shingles over worn roofing in this catalog.

VIDEO ON THE TOPIC: Ac pipes manufacturing

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Asbestos Products and Companies List

Bollaert, Chicago, Ill. The present invention relates to abestos-cement building materials and method of making the same. The invention is primarily concerned with the production of asbestos-cement building materials in the form of sheets such as are used either as siding or as shingles, and particularly when the said material is provided with an ornamented surface.

The manufacture of asbestos-cement building materials, such for example as shingles, has grown into a large industry and the processes for manufacturing these shingles or other similar material has generally fallen into two general types of manufacturing procedure. One of these types is the so-called Norton process which is a dry process in which a mixture of suitable quantities of Portland cement or its equivalent and a fibrous material such as asbestos fiber is placed upon a traveling belt, is then moistened with sufflcient water to make a pressable material which is then compacted and pressed into shape either by rolls or hydraulic presses, eventually being allowed to harden and set.

In the second process use is made of machinery which is very similar to that employed in the manufacture 'of multiple layers or laminations of cardboard. This method, which is generally known by the name of the original inventor thereof, Hatschek, makes use of vats or tanks containing a suspension of asbestos fiber and Portland cement in water, the suspension being of more or less flowable consistency. Rotating in these vats are foraminou cylinders, usually covered with a fine mesh metallic screen, which serve to pick up a thin film of the asbestos-cement composition which is then transferred to a continuously moving transfer belt made up of an absorbent material such for example as a woven or felted fabric.

Suction boxes on the opposite sides of the fabric serve to draw water out of the thus applied layer. It is usually customary to employ a plurality cure. The cure is often aided by submitting the sheets to the action of a highly heated steam atmosphere in which the cure can be accomplished in from 2 to 6 hours. The sheets are then cut up into suitable sizes, into shingles, strips, rectangles, sheets, or whatever shape it may be desired to produce.

Such asbestos-cement sheets are usually characterized by a rather drab and uninteresting appearingcolor which is that of Portland cement. Moreover, their surfaces are usually fairly rough due to their embossed texture to obtain a desirable shingle surface, and in cities where there is much smoke, dirt and dust, buildings provided with such sheets often become quite ugsightly.

While attempts have been made to correct these evils by providing such finished sheets with various types of coating or painting compositions, such application of separate coatings involves of course additional labor and material, particularly as most of these coatings have to be baked in order to be sufficiently adherent and weather resistant. A demand has therefore sprung up for more or less ornamental asbestos-cement siding and shingles which present a more pleasing appearance, with a smooth surface to which dirt will not adhere; They also present a variegated appearance occasioned by a difference in the color of the various areas of the product.

A number of proposals have been made to accomplish this, as for example by applying to the of such layers and then to accumulate these on a large drum from which, when the layers have accumulated to a. In so doing, the press, or at least one platen thereof, may be provided with a suitable mold so as to impress into the material a suitable design such for example as an imitation of wood grain.

The sheets are thereafter allowed to set and freshly formed sheets a suitable coloring composition which is sprayed thereonto and which then dries and hardens with the drying and hardening of the sheets themselves. Other methods involve the application to the finished sheets of sprays of penetrating coloring matter or the formation thereon of designs, by means of granules of a suitable composition, which are compatible with the Portland cement and asbestos of the shingles or sheets.

When exposed to the weather the granules soon become loose and fall oil, leaving an undesirable surface. All of these operations, however, require the installation of rather cumbersome special equipment which it is the object of the present invention to avoid while yet producing a pleasing, at least two-toned, asbestos-cement building material in the form of either sheets or shingles, having the appearance of a wood grain texture, or other ornamental designs and at the same time having a smooth surface.

Accordingly it is one of the objects of the present invention to produce at least two-tone asbestos-cement sheets which have a body of a numfilter cylinder It contained in container 5. Pulley 24 is mounted so as to be adjustable, so that the tension on the belt can be controlled. The filter cylinder III in the base veneer mixture tank 8 will of course continually pick up a 1 base veneer material of whatever color it happens for the carrying out of the process for the production of the materials just mentioned.

Other objects of the present invention will become apparent from the further description herein below, and from the concurrently filed drawing in which:.

Self-evidently therefore the base veneer will be visible at those portions where it is not covered by the top veneer. The result will be the production of an ornamented asbestos-cement sheet with the ornamentation being a part thereof. Thus for example there may be provided an asbestos-cement making machine such as broadly illustrated in Fig. An endless fabric belt I4 runs over suitable supporting pulleys I5, 20, 2 , 22, 23, 24 and 25 in the direction of the arrows, the said belt l4 being in contact with the periphery of the filter cylinders l6, l1, l8 and I9, so that any of the asbestos-cement composition, which is'picked up by the cylinders in accordance with the well known Hatschek method, will be transferred to the said fabric belt I4.

In order to withdraw water which may be in this belt, there are provided a plurality of suction boxes 26, 21, 28, 29, 30, 3 and The boxes and 3 serve to draw the residual of extractable water from the multiple layers of the composition adhering to belt I4; the very last numbered box 32 serving to withdraw any water or moisture remaining on the belt before it makes its contact with the first valve Inasmuch, however, as it is desired to accumulate a number of uncolored layers or natural colored layers, there is provided a.

The last tank, I9, is provided with a perforated wash-down pipe 35 having a number of perforations 36 which eventuate sprays 31 which can be directed against the surface of the filter cylinder I9.

The said pipe 35 is mounted in sliding supporting members 38 and 39 and is arranged to be reciprocably moved therein by means of the mechanism 40 shown in Fig. One end of this pipe is closed, as for example by means of a cap 41, while the other end is connected by means of a flexible hose with a water pipe 49, there also being provided a suitable shut off If it is desired to have, for example, as in the prior art, only a single veneer layer then the pipe 35 can be held stationary and all the sprays kept in use, so that all of the material will be washed back.

However, when it is desired to allow some of the material from tank 9 to get on to the sheet, then the spray will be interrupted at least so far as a number of the perforations 36 is concerned. For instance, the third one from each end may be allowed to remain open, while the others are closed by means of shut-oil" devices such as valves, plugs, sleeves and the like.

Increase and decrease of spraywater pressure will also add to the variation. The result will be of course a washing back of the top veneer mixture at the points where the particular sprays which are in operation impinge against the periphery of the filter cylinder I9. The result will be the formation of a sheet which has a continuous base veneer layer but a discontinuous top veneer layer, the top veneer being applied only to those areas where there is no spray.

Let it be assumed for instance that a six layer thick material is to be made. The operation will then be as follows:. For a sumcient length, to correspond to the desired size of the accumulator roll, say for instance, 13 feet, the belt I4 is allowed to contact cylinders I6, I!

This operation may be fully automatic and synchronized with the accumulator roll so that the veneer will be applied at the proper time to form a 13 foot surface on the belt and will be picked up by the accumulator roll on the first or face layer, The accumulated sheet is then cut from the roll in a well known manner which does not interrupt the rotation thereof, and is then received upon take-oil conveyor Belt.

After, say, about six suchlayers have accumulated, the spray 34 out of pipe 33 is shut off as a result of which there will now be impressed upon the material on belt I a layer of the base veneer, which, for instance, and purely for purposes of example, may be colored an ultramarine blue. The continuous spray which had been directed' against cylinder is in tank 9 would be shut off and a spray allowed only to play, say, from the third and sixth holes from the left of pipe 35, with the result that there will be a washback only through the third and sixth sprays.

There will thus result a sheet such as shown Fig. The irregularity is occasioned by the reciprocation of the pipe 35 under the influence of the reciprocating mechanism of which the lever l I, the slot 45, and the pin 46, attached to the pipe 35, are a part. It will be evident that by obturating any particular one of the holes 36 in the pipe 35, any desired orientation of wash-back can be obtained, and therefore the design of the shingle changed at will.

It is also desired to have present in the tank 9 a second wash-back pipe 52 provided with perforations 53 which may serve as a permanent spray-back pipe to be used when all of the top veneer layer'is to be washed oif, and which may be shut off whenever a top veneer is to be picked up, at which time, however, the pipe Methods for shutting off the spray coming from pipe 52 and the putting into play of the spray from pipe 35 will be under the control of the operator by suitable quick-opening valves which are so well known that they need not be particularly herein described, or may be entirely automatic and synchronized with the accumulator roll and set for the desired number of layers per sheet.

For the sake of simplicity, the permanent spray-back pipe has been omitted from Fi 2. The further disposition of the sheets produced is of course outside of the process of the present invention, and follows well known procedure fully familiar to those who are engaged in the manufacture of asbestos-cement sheets. An alternative method for producing a decorative two-tone asbestos-cement shingle is illustrated in Figs.

This is accomplished by providing the cylinder I9, as shown in Fig. Therefore, the cylinder will pick up veneer mixture only at the points where it is not plugged up by the areas 60 to For that type of operation of course the pipe 35 and perforations 36 may either be omitted, or simply kept inactive.

The result will be the application of a partial top veneer layer to the base veneer layer, which will be visible through those areas which are free of the top veneer. In the illustration in Figs. Self evidently the designs may be highly ornamental such as in the form of stars,. The operator thus has it within his power to produce a shingle or siding material which has two coats, one of a base veneer and the other of a top veneer, the top veneer being sufllciently discontinuous so as to allow some of the base veneer layer to be visible.

It will be self-evident that the. The washing back of the veneer layers all over the cylinder is, of course, a well known expedient and has been practiced in this art for many years, and therefore substantially all machines for the manufacture of absestos-cement shingles by the wet or Hatschek method are already provided with wash-back pipes.

All that is required, therefore, is to provide means for shutting off certain of the perforations in these pipes so that the wash-back, when desired, can be accomplished at selected areas, and also if desired to provide means to impart oscillatory movement to the pipe so that the wash-back areas will have an undulatin outline.

Therefore the present method can be adapted, without great expense, to presently available equipment which makes the method of the present invention very attractive, because it can be so readily placed into operation without the purchase of much additional equipment.

Moreover, if the second modification is to be used, all that is necessary is to take the cylinder which applies the top veneer layer and to block out certain areas of the wire mesh cloth thereof with an obturating medium so that at that point it will not pick up the top veneer layer material.

The exact means for producing reciprocatory movement of the pipe need not be shown and any mechanical equivalent is to be considered as within the scope and purport of the present invention.

Process of producing color-ornamented asbestos-cement sheets which comprises building up a laminated structure of unset asbestos-cement composition, applying a continuous base veneer layer of a colored asbestos-cement composition thereto, picking up a continuous layer of an unset differently colored asbestos-cement top veneer composition on a. Other objects of the present invention will become apparent from the further description herein below, and from the concurrently filed drawing in which: Fig.

The operation will then be as follows: For a sumcient length, to correspond to the desired size of the accumulator roll, say for instance, 13 feet, the belt I4 is allowed to contact cylinders I6, I! By varying the pressure of the wash-back sprays, further variation can be effected.

Self evidently the designs may be highly ornamental such as in the form of stars, crescents, or flowers, or any other desired shape. Applicant claims: Process of producing color-ornamented asbestos-cement sheets which comprises building up a laminated structure of unset asbestos-cement composition, applying a continuous base veneer layer of a colored asbestos-cement composition thereto, picking up a continuous layer of an unset differently colored asbestos-cement top veneer composition on a.

USA en. Method of and apparatus for applying aqueous dispersions in manufacture of paperboard and the like. Apparatus for the production of designs in paper, millboard, vegetable leather substitute, and linoleum substitute. Corrugated sheet of fibrous materials and hydraulic binding agents and methods and apparatus for their manufacture.

Method for producing a wall, roadway, sidewalk or floor of cementitious material. CNC en. KRB1 en. MXA en.

SEL en. Method and apparatus for manufacturing fiber-reinforced, hydraulically bound objects. EPB1 en. EPA2 en.

Asbestos still pushed in India and business is booming

Objectives: In an assessment of the risk of asbestos fibres release from asbestos cement materials, an important role is played by the assessment of the surface corrosion and by the disaggregation of asbestos cement. The aim of this work is to evaluate the differences among several methods used for the risk assessment that lead to a specific choice of abatement techniques. Results: The results obtained with the methods, proposed in this study, for the risk assessment of the decay of asbestos cement roofs show slight differences among them, only one deviates from the others in judgement on the state of conservation of the roof. Conclusions: It is very important to train the operator conducting the study since a completely subjectivity-free method does not exist. Whatever method is used will always be affected by the subjectivity linked to the competency and the training of the operator.

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The executives mingled over tea and sugar cookies, and the chatter was upbeat. Their industry, they said at the conference in the Indian capital, saves lives and brings roofs, walls and pipes to some of the world's poorest people. The industry's wonder product, though, is one whose very name evokes the opposite: asbestos. A largely outlawed scourge to the developed world, it is still going strong in the developing one, and killing tens of thousands of people each year. The International Labor Organization, World Health Organization, the wider medical community and more than 50 countries say the mineral should be banned.

Asbestos Cement Sheets

Among all building materials, concrete is the most commonly used—and there is a staggering demand for it. However, as we strive to build taller structures with improved seismic resistance or durable pavement with an indefinite service life, we require materials with better performance than the conventional materials used today. These improved properties may be defined in terms of carbon footprint, life-cycle cost, durability, corrosion resistance, strength, ductility, and stiffness. Addressing recent trends and future directions, Mechanics of Fiber and Textile Reinforced Cement Composites presents new opportunities for developing innovative and cost-effective materials and techniques in cement and concrete composites manufacturing, testing, and design. The book offers mathematical models, experimental results, and computational algorithms for efficient designs with fiber and textile reinforced composite systems. It explores alternative solutions using blended cements, innovative reinforcing systems, natural fibers, experimental characterization of key parameters used for design, and optimized designs. Each chapter begins with a detailed introduction, supplies a thorough overview of the existing literature, and sets forth the reasoning behind the experimentation and theory. Documenting the composite action of fibers and textiles, the book develops and explains methods for manufacturing and testing cement composites.

Environmental health survey in asbestos cement sheets manufacturing industry

Asbestos is a general name that applies to several types of fibrous silicate minerals. Historically, asbestos is best known for its resistance to flame and its ability to be woven into cloth. Because of these properties, it was used to make fireproof stage curtains for theaters, as well as heat-resistant clothing for metal workers and firefighters. More modern applications of asbestos take advantage of its chemical resistance and the reinforcing properties of its fibers to produce asbestos-reinforced cement products including pipes, sheets, and shingles used in building construction. Asbestos is also used as insulation for rocket engines on the space shuttle and as a component in the electrolytic cells that make oxygen on submerged nuclear submarines.

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Bollaert, Chicago, Ill. The present invention relates to abestos-cement building materials and method of making the same. The invention is primarily concerned with the production of asbestos-cement building materials in the form of sheets such as are used either as siding or as shingles, and particularly when the said material is provided with an ornamented surface.

EP0068741B1 - Boards and sheets - Google Patents

For much of the 20th century, asbestos cement sheets provided builders with a rugged solution for simple roofing and siding projects. While these products were cheap to manufacture and buy, their true cost emerged years later in the form of deadly asbestos-related illnesses. Fibrous cement sheets are more durable than drywall and easier to work with than concrete, and they have numerous applications in construction.

About small-scale asbestos mining and milling facilities and 33 large - scale asbestos manufacturing plants, 17 asbestos-cement product manufacturing plants and 16 other than asbestos-cement product plants are situated in India. The present study reveals the exposure of commercial asbestos chrysotile in the occupational as well as ambient air environment of the asbestos-cement AC sheets industry using membrane filter method of Bureau of Indian Standards BIS. The fibre concentrations in 15 samples collected in the occupational environment at ingredient feeding site, sheet-producing site, fibre godown were 0. Morphological analysis of samples, further under phase contrast and polarized microscopy indicates the presence of chrysotile asbestos, which acts as carcinogen as well as co-carcinogen. A clinical examination of exposed subjects reveals that there was no case of clubbing, crepitation, ronchi and dyspnea on exertion; however, obstruction and restriction were The study revealed that chrysotile asbestos is emitted in the occupational as well as ambient environment that may cause adverse health impact.

Akers Consulting GmbH -

Australia mined asbestos for more than years and manufactured and imported asbestos products. There is a legacy of in situ asbestos throughout the built environment. The aim of this study was to identify the possible sources of current and future asbestos exposure from the built environment. Telephone interviews with environmental health officers, asbestos removalists, and asbestos assessors in Australia sought information about common asbestos scenarios encountered. There is a considerable amount of asbestos remaining in situ in the Australian built environment. Potential current and future sources of asbestos exposure to the public are from asbestos-containing roofs and fences, unsafe asbestos removal practices, do-it-yourself home renovations and illegal dumping. This research has highlighted a need for consistent approaches in the regulation and enforcement of safe practices for the management and removal of asbestos to ensure that in situ asbestos in the built environment is managed appropriately.

Hydraulic BOLIVIA Possibilities For Beginning Industrial Development In REP I 0; Concrete G Asbestos Cement Products Plant G Refractory Plant Pottery G Installation Machinery G Equip WEST GERMANY The Market For Building.

Eco-efficient Construction and Building Materials provides essential reading about materials for the construction industry in the twenty-first century. It covers the latest findings in the field, especially the toxicity aspects, embodied energy, construction and demolition wastes, the use of wastes in concrete, masonry units, materials reinforced with vegetable fibres, earth construction, the durability aspects, and also the importance of nanotechnology to the development of more environmentally-friendly materials. Based on more than nine hundred references, Eco-efficient Construction and Building Materials is of fundamental importance to academics, engineers and architects who are dedicated to the creation of a greener and more holistic construction industry.

US2573659A - Method of making color ornamented asbestos-cement sheets - Google Patents

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Environmental health survey in asbestos cement sheets manufacturing industry

Asbestos cement , genericized as fibro or fibrolite - short for "fibrous or fibre cement sheet" - and AC sheet , is a building material in which asbestos fibres are used to reinforce thin rigid cement sheets. The material rose to necessity during World War II to make sturdy, inexpensive military housing, and continued to be used as an affordable substitute for many roofing products following the war. Asbestos-cement faced competition with the aluminum alloy , available in large quantities after WWII, and the reemergence of wood clapboard and vinyl siding in the mid to late twentieth century. Asbestos-cement is usually formed into flat or corrugated sheets or piping, but can be molded into any shape wet cement can fit.

Asbestos is not illegal in the United States and is still widely used in many electrical insulations, roofing, and fireproofing materials. Asbestos is still widely used in building materials like insulation, plaster, wallboard, vinyl and laminate flooring, siding, and cement pipe.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website. Manufacture of asbestos-cement products: this article describes the processes used to manufacture asbestos cement sheet, siding, roofing, pipe, and molded products. Dry, wet, and wet mechanical processes that were used to produce cemetn asbestos products are explained and illustrated. Our page top photograph shows badly broken cement asbestos roofing shingles on a building in upstate New York.

Через десять минут Беккер уже сидел в буфете АНБ, жуя сдобную булку и запивая ее клюквенным соком, в обществе очаровательной руководительницы Отделения криптографии АНБ. Ему сразу же стало ясно, что высокое положение в тридцать восемь лет в АНБ нельзя получить за красивые глаза: Сьюзан Флетчер оказалась одной из умнейших женщин, каких ему только доводилось встречать. Обсуждая шифры и ключи к ним, он поймал себя на мысли, что изо всех сил пытается соответствовать ее уровню, - для него это ощущение было новым и оттого волнующим.

Час спустя, когда Беккер уже окончательно опоздал на свой матч, а Сьюзан откровенно проигнорировала трехстраничное послание на интеркоме, оба вдруг расхохотались.

И вот эти два интеллектуала, казалось бы, неспособные на вспышки иррациональной влюбленности, обсуждая проблемы лингвистической морфологии и числовые генераторы, внезапно почувствовали себя подростками, и все вокруг окрасилось в радужные тона.

Хейл почувствовал, как кровь ударила ему в голову. Он был уверен, что спрятал все следы, и не имел ни малейшего понятия о том, что Сьюзан были известны его действия. Понятно, почему она не хотела верить ни одному его слову.

Он почувствовал, как вокруг него выросла стена, и понял, что ему не удастся выпутаться из этой ситуации, по крайней мере своевременно.

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  1. Kagalkree

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