Pipe-clays

Various pipes are used to smoke tobacco, including hooklis (clay pipes, western India), and chillum (a straight, conical pipe held vertically, used in northern India), which may be shared. 

Toluene diisocyanate is commonly produced as a mixture of the 2,4- and 2,6-iso-niers, that is used as a monomer in the preparation of polyurethane foams, elastomers and coatings, as a cross-linking agent for nylon-6, and as a hardener in polyurethane adhesives and finishes. Polyurethane elastomers made from toluene diisocyanates are used in coated fabrics and clay-pipe seals. Polyurethane coatings made from toluene diisocyanates are used in floor finishes, wood finishes and sealers, and in coatings for aircraft, tank trucks, truck trailers and truck fleets (United States National Library of Medicine, 1997). 

Fig. 25.14 Schistosomiasis portal fibrosis (so-called clay pipe-stem fibrosis) (HE)...

Boova, A.A., Chemical Resistant Joints for Vitrifield Clay Pipe Conveying Chemical Wastes, Paper 229, NACE CORROSION/80, Chicago, IL (March 3-7,1980). 

For almost 100 years, hot asphalt has been employed as a joint filler for bell-and-spigot vitrified clay pipe used to construct sanitary sewers. The joints in the pipe are assembled and poured much in the way described for clay industrial sewer lines in the Industrial Waste section of this book. Where used for this pur-... 

Obviousiy oakum packing with a hot asphait pitch or tar backing cannot be used for present day industrial wastes, nor can one expect to get fully tight joints in this manner even for gravity sanitary lines, whether they are backed with a hot poured sealant or packed with Portland cement. In present day design, joints in vitrified clay pipe are most often specified in the manner shown in Sketch 1. 

TABLE 2A Dimensions of Vitrified Clay Pipe (SI Units)... 

The clay pipe used for conveyance of industrial wastes should be unglazed, extra strength pipe, conforming to ASTM specification C 700-71. 

Strong aikalies will damage the pipe. If the alkali content (pH) is expected to be high enough to destroy a vinyi ester mortar, it will probably be too high for the pipe itself. If this possibiiity arises the matter should be discussed with the pipe manufacturer or the National Clay Pipe Institute. Consider aiso the temperature at which liquid streams may enter the pipe. The cited standard limits service conditions to 140°F or lower. If very hot liquids are to enter the system, this too shouid be discussed with the pipe manufacturer. 

A common joint design for clay pipe, one which the pipe manufacturer will probably try to sell, is a "pressure joint." For this kind of joint an elastomeric or flexible collar is set into, and usually cemented to, the inside of the bell. The inside dimension of the collar is smaller than the outside dimension of the spigot, so when the spigot is seated in the bell the collar squeezes tightly against... 

Chemically resistant masonry joints in clay pipe are rigid. Ground movement, such as settlement, can therefore break the pipe. For this reason it is important that all industrial waste lines be laid with continuous support. No matter what opinion others may have of the stability of the soil in the area where the pipe is to be laid, this writer has never seen any trench excavation, no matter how well prepared, that did not require adjustment to attain the suitable smooth surface and slope after the trenching operation had been completed. These adjustments require fill in some spots and further surface removal in others. In addition bell excavations are required to provide working room to make the joints. After the line is in service, heavy rains, flooding and even percolation of groundwater can cause soil movement above and around the pipe, and eventually, without uniform support, movement will take place that breaks the pipe. 

During installation of clay pipe and manholes, careful inspection and rigid compliance with specifications is essential. It should be borne in mind that after installation, it is impossible to inspect the workmanship from the outside, and internal inspection is possible only for the exposed surface. There is no way that an inspector can verify that either the membrane or the substrate of the manhole comply with specifications, that holidays do not exist, and that membrane thicknesses are as specified. The inspector should check all work carefully as it progresses, including all membranes prior to brick installation, and all joints in pipe as they are caulked. 

In the last few years, a procedure has been developed for placing a seal on the inside of a leaking clay pipe line. The procedure is as follows ... 

The behavior of ANFO in 0.1- and 0.2-m-diameter cylinders has been studied in field tests (4, j5). Most of the data were obtained in high-speed photography of detonations of explosive-filled plastic or clay pipes immersed in water. The detonation velocity can be determined quite accurately and in the water tank tests, the propagation of the shock in the water and the motion of the interface between the water and the pipe can be followed. An equation of state for the explosive reaction... 

Another method is for the performer to produce two clay pipes, both empty, and to all appearance unprepared but on putting one of the pipes into his mouth and holding the other bowl inverted over it, smoke at once begins to pour forth from between them. Care must be taken to exhale (blow out) and not inhale (breathe in) the fumes. 

Extraction Stoneware Clays Pipe-clays Boulder Clays Bentonite Fuller s Earth... 

A gigantic combined de-airing extmsion machine with a barrel diameter as wide as 850 mm and the capacity for putting out 12 columns of brick at once has little in common with a tiny, 20 mm-diameter micro-extmder. Or, compare a vertical extmder for clay pipes with diameters up to 1.50 m with an intermittent-action piston extmder that can work vertically as well as horizontally. Or how about a twin-screw extruder or piston extmder sporting extmsion pressures up to 400 bar in contrast with a huge vacuum extmder for forming electrical porcelain slugs at relatively low pressure ... 

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