Edge runners

KoUer-gang, m., -mUhle, /. edge mill, edge runner. 

All ball, pebble, rod and cone mills, edge runner mills, tube mills, vibration mills and some ring ball mills may be used wet or dry except where stated. The perl mills, sand mills and colloid mills may be used for wet milling only. 

Mill cake. In blackpowder manufacture, a product taken from the edge runner mills. 

Gyratory crusher Edge runner mill NEI pendulum mill... 

In the edge runner mill shown in Figure 2.8 a heavy cast iron or granite wheel, or muller as it is called, is mounted on a horizontal shaft which is rotated in a horizontal plane in... 

The preparation of infusible (loose powder) ammonium nitrate mixtures is usually carried out in the same way as the manufacture of composite mining explosives. Since the military explosives are not very sensitive to mechanical stimulants, and it is important to obtain a high density, mixing is usually performed by edge runner mills. 

Charcoal is usually milled in either ball mills or disintegrators. It may be given a preliminary treatment in edge runners. 

Sulphur is milled in similar equipment, but in some countries edge runners or rollers are used. Since sulphur is strongly electrified on milling it is advisable to add... 

In some factories the three ingredients are dampened with 8-10% of water and then mixed in wooden drums with wooden balls (Fig. 92). The balls work by a kneading action so that to some extent they replace mixing in an edge runner. The... 

The edge runner (Figs. 93 and 94) consist of two heavy (500-600 kg) cast-iron wheels approximately 1.5 m dia. and. 5 m wide. The wheels rotate around horizontal shafts connected by a clutch with l ertical axle (7) so as to enable clutch (2) to be lowered or raised together with the suspended wheels (3). The vertical axle butts against the bearing (4) situated in the centre of an iron tray (5). Near the wheels... 

Near the vertical axle of the edge runner there is a tube for supplying the charge with the necessary amount of water. In modern factories the water storage tank and the cock regulating the water inflow are situated in an adjacent room from which the apparatus is operated. 

This principle of mixing by means of suspended wheels was not introduced until the end of the nineteenth century before then the kneading process in edge runners was the most dangerous operation in the manufacture of blackpowder. Wooden... 

After the kneading has been completed the mass is pressed to form press cakes which are then dried. These cakes are hard and give a conchoidal fracture. Pressing is done either (a) in the same edge runners (b) in hydraulic presses. 

Pressing in edge runners as carried out in France is effected by lifting the scrapers after mixing has been completed, with the runner in slow-speed motion. The wheels knead the mass which is not now raked by the scrapers. The material thus obtained is in the form of a hard press cake which is then air-dried at temperatures from 20 to 30°C. 

The damp mass of powder removed from the edge runners is spread in an even layer up to 9 cm thick over bronze or copper plates. Several layers are thus superimposed and compressed in a press (Fig. 96) at a pressure from 25 to 35 kg/cm2 for... 

The sieve frames should be made of wood to avoid the danger of friction and impact. Brass mesh (formerly perforated parchment) or silk muslin is used, stretched on frames so that the sieves can be easily arranged according to the grain sizes required. Dust separated out by sieving is sent back to the edge runners. 

Cannon powder is manufactured by kneading in an edge runner followed by pressing the cake to a high density. Afterwards the mass is corned, moistened to 3-3.5% water content and pressed again into cakes at a pressure of 100 kg/cm2. 

According to J. Taylor and Gay [4] this is probably due to a relatively high rate of detonation of mixtures manufactured in an edge-runner mill. The influence of edge-runner mixing on rate of detonation has already been discussed. 

Schneiderite, for instance, consisting of a mixture of ammonium nitrate and dinitronaphthalene, is mixed in an edge runner in batches of 60 kg. The mixing... 

Medard and Le Roux [1] examined the influence of various methods of mixing on the properties of ammonium nitrate explosives ( Explosifs du type N ). They found that mixing in heavy (5 ton) edge-runners gives explosives of higher sensitiveness and rate of detonation than the same explosives mixed in kneaders of the Werner-Pfleiderer type. 

For mixing dynamites, in particular those containing less nitroglycerine, wooden edge runners of a special design are employed in France (Fig. 177). The tub (1) has the base of ebonite plates (2). The wheels of the runner are also covered with ebonite bands (5). 

Mixing of insensitive ingredients of explosives also can be done in rotary drums, but if the components are not previously pulverized, the so-called pan mixers also known as1 wheel mills or edge runners are used. 

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