Pugmill

Last updated
Clay body being extruded from a de-airing pug Sevres - Moulin - boudineuse-desaereuse 027.jpg
Clay body being extruded from a de-airing pug

A pugmill, pug mill, or commonly just pug, is a machine in which clay or other materials are extruded in a plastic state or a similar machine for the trituration of ore. [1] Industrial applications are found in pottery, bricks, cement and some parts of the concrete and asphalt mixing processes. A pugmill may be a fast continuous mixer. A continuous pugmill can achieve a thoroughly mixed, homogeneous mixture in a few seconds, and the right machines can be matched to the right application by taking into account the factors of agitation, drive assembly, inlet, discharge, cost and maintenance. [2] Mixing materials at optimum moisture content requires the forced mixing action of the pugmill paddles, while soupy materials might be mixed in a drum mixer. A typical pugmill consists of a horizontal boxlike chamber with a top inlet and a bottom discharge at the other end, 2 shafts with opposing paddles, and a drive assembly. Some of the factors affecting mixing and residence time are the number and the size of the paddles, paddle swing arc, overlap of left and right swing arc, size of mixing chamber, length of pugmill floor, and material being mixed.

Contents

Common construction and industrial uses

Road Base - Dense well-graded aggregate, uniformly mixed, wetted, and densely compacted for building the foundation under a pavement.

Lime Addition to asphalt – Lime may be added to the cold feed of an asphalt plant to strengthen the binding properties of the asphalt.

Flyash Conditioning – Wetting fly ash in a pugmill to stabilize the ash so that it won’t create dust. Some flyashes have cementitious properties when wetted and can be used to stabilize other materials.

Waste stabilization – various waste streams are remediated with pugmills forcing the mixing of the wastes with remediation agents.

Roller-compacted concrete – (RCC) or rolled concrete is a special blend of concrete that has the same ingredients as conventional concrete but in different ratios. It has cement, water, and aggregates, but RCC is much drier and essentially has no slump. RCC is placed in a manner similar to paving, often by dump trucks or conveyors, spread by bulldozers or special modified asphalt pavers. After placement it is compacted by vibratory rollers. The “stiff” nature of RCC may require a paddle type pugmill to force the materials to mix completely and discharge easily.

Ceramics pug mills, or commonly just "pugs", are not used to grind or mix, rather they extrude clay bodies prior to shaping processes. Some can be fitted with a vacuum system that ensures the extruded clay bodies have no entrapped air. According to the 1913 edition of Webster's Dictionary, a clay pug mill typically consists of an upright shaft armed with projecting knives, which is caused to revolve in a hollow cylinder, tub, or vat, in which the clay body is placed.

Electrically driven pug mills have not completely replaced the laborious process of kneading clay by hand and foot to remove entrapped air. This is especially true in remote areas without electricity. Some ceramists, like Korea's Master Kim Se-yong, still knead clay by foot as a matter of choice. [3]

Pugmills that run intermittently are used in the kaolin mining industry to mix certain grades of kaolin clay with water.

See also

Related Research Articles

<span class="mw-page-title-main">Concrete</span> Composite construction material

Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined.

<span class="mw-page-title-main">Road surface</span> Road covered with durable surface material

A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.

<span class="mw-page-title-main">Asphalt concrete</span> Composite material used for paving

Asphalt concrete is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with bitumen, laid in layers, and compacted.

<span class="mw-page-title-main">Mixing (process engineering)</span> Process of mechanically stirring a heterogeneous mixture to homogenize it

In industrial process engineering, mixing is a unit operation that involves manipulation of a heterogeneous physical system with the intent to make it more homogeneous. Familiar examples include pumping of the water in a swimming pool to homogenize the water temperature, and the stirring of pancake batter to eliminate lumps (deagglomeration).

<span class="mw-page-title-main">Concrete mixer</span> Device that combines cement, aggregate, and water to form concrete

A concrete mixer is a device that homogeneously combines cement, aggregate, and water to form concrete. A typical concrete mixer uses a revolving drum to mix the components. For smaller volume works, portable concrete mixers are often used so that the concrete can be made at the construction site, giving the workers ample time to use the concrete before it hardens. An alternative to a machine is mixing concrete by hand. This is usually done in a wheelbarrow; however, several companies have recently begun to sell modified tarps for this purpose.

Full depth recycling or full depth reclamation (FDR) is a process that rebuilds worn out asphalt pavements by recycling the existing roadway.

<span class="mw-page-title-main">Stone mastic asphalt</span> Road construction material

Stone mastic asphalt (SMA), also called stone-matrix asphalt, was developed in Germany in the 1960s with the first SMA pavements being placed in 1968 near Kiel. It provides a deformation-resistant, durable surfacing material, suitable for heavily trafficked roads. SMA has found use in Europe, Australia, the United States, and Canada as a durable asphalt surfacing option for residential streets and highways. SMA has a high coarse aggregate content that interlocks to form a stone skeleton that resists permanent deformation. The stone skeleton is filled with a mastic of bitumen and filler to which fibres are added to provide adequate stability of bitumen and to prevent drainage of binder during transport and placement. Typical SMA composition consists of 70−80% coarse aggregate, 8−12% filler, 6.0−7.0% binder, and 0.3 per cent fibre.

<span class="mw-page-title-main">Feed mixer</span>

Feed mixers are used in feed mills for the mixing of feed ingredients and premixes. The mixer plays a vital role in the feed production process, with efficient mixing being the key to good feed production. If feed is not mixed properly, ingredients and nutrients will not be properly distributed when it comes time to extrude and pelletize the feed, or if the feed is to be used as mash. This means that not only would the feed not have nutritional benefit, it would be bad for the animals that are eating it.

<span class="mw-page-title-main">Roller-compacted concrete</span> Concrete blend used in dam construction

Roller-compacted concrete (RCC) or rolled concrete (rollcrete) is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Portland cement. The partial substitution of fly ash for Portland Cement is an important aspect of RCC dam construction because the heat generated by fly ash hydration is significantly less than the heat generated by Portland Cement hydration. This in turn reduces the thermal loads on the dam and reduces the potential for thermal cracking to occur. RCC is a mix of cement/fly ash, water, sand, aggregate and common additives, but contains much less water. The produced mix is drier and essentially has no slump. RCC is placed in a manner similar to paving; the material is delivered by dump trucks or conveyors, spread by small bulldozers or specially modified asphalt pavers, and then compacted by vibratory rollers.

Remediation of contaminated sites with cement, also called solidification/stabilization with cement is a common method for the safe environmental remediation of contaminated land with cement. The cement solidifies the contaminated soil and prevents pollutants from moving, such as rain causing leaching of pollutants into the groundwater or being carried into streams by rain or snowmelt. Developed in the 1950s, the technology is widely used today to treat industrial hazardous waste and contaminated material at brownfield sites i.e. abandoned or underutilized properties that are not being redeveloped because of fears that they may be contaminated with hazardous waste. S/S provides an economically viable means of treating contaminated sites. This technology treats and contains contaminated soil on site thereby reducing the need for landfills.

This is a list of pottery and ceramic terms.

<span class="mw-page-title-main">Coal combustion products</span> By-products of coal combustion

Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs), are categorized in four groups, each based on physical and chemical forms derived from coal combustion methods and emission controls:

<span class="mw-page-title-main">Concrete plant</span> Equipment that combines various ingredients to form concrete

A concrete plant, also known as a batch plant or batching plant or a concrete batching plant, is equipment that combines various ingredients to form concrete. Some of these inputs include water, air, admixtures, sand, aggregate, fly ash, silica fume, slag, and cement. A concrete plant can have a variety of parts and accessories, including: mixers, cement batchers, aggregate batchers, conveyors, radial stackers, aggregate bins, cement bins, heaters, chillers, cement silos, batch plant controls, and dust collectors.

<span class="mw-page-title-main">Granulation</span> Forming grains or granules from a powdery or solid substance

Granulation is the process of forming grains or granules from a powdery or solid substance, producing a granular material. It is applied in several technological processes in the chemical and pharmaceutical industries. Typically, granulation involves agglomeration of fine particles into larger granules, typically of size range between 0.2 and 4.0 mm depending on their subsequent use. Less commonly, it involves shredding or grinding solid material into finer granules or pellets.

<span class="mw-page-title-main">Types of concrete</span> Building material consisting of aggregates cemented by a binder

Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.

Industrial agitators are machines used to stir or mix fluids in industries that process products in the chemical, food, pharmaceutical and cosmetic industries. Their uses include:

Soil stabilizers and road recyclers are engineering vehicles that were once similar machines; however, they are now specialised pieces of road making machinery and have developed into different machines. Other terms that are sometimes used are: road profiler, road reclaimer, road miller, road planer and pavement profiler. They are used in the process of full depth recycling.

A grinder-mixer is a type of agricultural machine used to process livestock feed from grain. A grinder-mixer is a portable mill that combines the mixing and grinding operations.

<span class="mw-page-title-main">Pasta processing</span> Process of making pasta

Pasta processing is the process in which wheat semolina or flour is mixed with water and the dough is extruded to a specific shape, dried and packaged.

<span class="mw-page-title-main">Mixing paddle</span>

A mixing paddle is a shaped device, typically mounted on a shaft, which can be inserted on the shaft end into a motorised drive, for the purpose of mixing liquids, solids or both. Paddle mixers may also be used for kneading. Whilst mounted in fixed blending equipment, the paddle may also be referred to as an agitator.

References

  1. "Pug-mill" def. 1. Oxford English Dictionary Second Edition on CD-ROM (v. 4.0) © Oxford University Press 2009
  2. "Pugmill Mixer Selection Guide | bulk solids handling". www.bulk-solids-handling.com. Archived from the original on 2015-10-03.
  3. From Earth to Light, Korean Ceramic Master Hand, Seyong Kim's Life , retrieved 2024-03-16