What is the ball mill ball? Ball mill is the basis of the important parts, especially the precision industrial ball plays a huge role in the development of national economy. In some special conditions, often need special material steel ball, to complete the required to achieve the function of the different environment. In fact, some special material steel ball has been widely used in the national economy each domain, including 9 cr18, 3 cr13 stainless steel, copper, aluminum, steel and titanium alloy agate, glass, ceramic ball, etc. Their popularization and application, not only promoted the development of the steel ball manufacturing, but also promote the technology development of related industries, science and technology progress.
Steel ball bearing is the most important part of, also is the rolling element bearing industry to use the most. Its quality directly affects the quality of bearing. Steel ball production process after the steel ball automatic cleaning, automatic surface testing (automatically weed out unqualified products), automatic rust and counting packaging, is the key factor affecting the quality of steel ball. Steel ball surface testing is an indispensable process in the manufacturing process of steel ball. Steel ball surface testing mainly includes surface scratch, rust, spots and so on the surface of the test. What is the coefficient of steel ball with? How do you determine the loading capacity of steel ball? Steel tube type coal mill, is a diameter of 2, 4 m, 3-10 m long cylinder, both ends on the tapered end cover; Attached to the hollow shaft. Hollow shaft neck on the bearing, through the transmission device drives the cylinder rotate. Wall lining cylinder body is equipped with wavy wear resistant steel armour, cylinder is equipped with a large number of 25-60 mm diameter of steel ball. On hollow shaft end cover at one end into the raw coal and hot air, one end is a mixture of air powder export, coal drying and grinding at the same time. Cylinder turns, steel and coal under the action of centrifugal force, be armor with a certain height, and then fall in coal will break, at the same time also is between the ball and the ball, the ball and armor of extrusion, rolling and grinding, grinding coal into coal, because from exports out of the drying agent. The advantages of ball mill is: can manufacture various coal; The sensitivity of the impurities in coal is poorer; Can work continuously for a long time and high reliability. The disadvantage is that: the heavy equipment, use steel; High investment; Run large noise; High power consumption than other coal mill grinding coal; The uniformity of pulverized coal index is low.
Domestic steel tube type coal mill model for DTM - * * * / * * *, its meaning is D - low speed; T - drum; M - coal mill; XXX/XXX - a set of Numbers, a semicolon is above the cylinder of cm in diameter, semicolon here is cylinder length on the number of centimeters. Such as DTM - 320/580 type said: coal mill barrel diameter of 3.2 m, barrel length 5.8 m. Another type of ball mills is DZM type, including Z type cylinder for cones. The speed of the ball mill, directly affect the steel ball and the movement condition of the coal and coal grinding process. Cylinder rotational speed is low, the steel ball coal can't be brought up, only in the lower rolling, grinding coal output is very small; If making a high speed, the centrifugal force is greater than its gravity acting Yu Gangqiu and coal, steel and coal will with the cylinder rotate together, is also lost ground coal action. In the condition of the minimum speed is called the critical speed. The best speed of cylinder should be cylinder body ball has the biggest hoisting height, the ball has the biggest impact, coal grinding effect is best. Actual work speed coal mill, the gearing ratio and its conditions, can't just wait for the best speed, but are close to. About domestic ball mill work speed and critical speed ratio between 0.74 0.80.
In loading of ball mill volume and the cylinder volume percentage, called ball coefficient, also known as loading rate of the ball. Different levels of cylinder body with the ball, the ball the size of the fill factor, directly affects the coal mill output and power consumption. Coal mill output and full of coefficient of 0.6 times the direct ball, and the power consumption and the direct ratio of 0.9 times. The value of general grinding machine in 0.20? - 0.30. Coefficient of concrete of steel ball mill with, need to determine the optimal value through tests. When the ball is full of coefficient is determined, also knew that the loading capacity of steel ball.
What are the requirements for steel ball diameter of ball mill load? Output of the ball mill is not only influenced by steel ball loading capacity, also related to the diameter of steel ball. Request has the certain ball diameter and different diameter of the ball to keep a certain proportion relations, general cylinder body ball diameter size in the range of 25-60 mm. If the cylinder body is large diameter of the ball, the impact is bigger, advantageous to break up large lump coal, but, because of the large gap between ball and relatively small surface area, extrusion, grinding effect is abate, adverse to the coal mill output and fineness of pulverized coal. Cylinder body small diameter steel ball is too much, the impact is small, can make the coal mill output drop, at the same time, due to the steel ball surface area increases relatively, will increase the steel ball wear, grinding coal power consumption. Coal mill in the process of operation, as a result of wear and tear, weight and diameter of steel ball have been reduced, so need to add new ball regularly, in order to maintain a certain steel ball loading capacity. Generally add for the larger ball, filling the ball quantity should be according to the steel ball wear rate (the wear amount of every tons of coal ball mill and grinding coal quantity to determine. Coal mill run after a certain period of time, the number of steel cylinder body small diameter increase. So the general running about 3000 hours later, to stop cleaning ball, in order to remove the diameter is less than 15 mm ball and has been broken, and at the same time make up new ball. Steel drum breakage of coal mill from time to tome what phenomenon?
Because of coal feeder fault, high raw coal moisture, sundry goods jams, the original coal without reason of coal or jam, can cause broken coal mill and the main phenomenon is:
(1) coal mill export desiccant temperature increase.
(2) the coal mill inlet negative pressure increase, export pressure decreased; Inward and outward pressure differential is reduced, row of powder machine export wind pressure increased.
(3) the engine flow increase, in the coal mill noise increased significantly.
(4) broken coal signals.
How to deal with when the ball cartridge breakage of coal mill?
(1) appropriate down coal mill inlet air door, open the inlet air cooling damper (or temperature), to control the outlet temperature of the coal mill is not overrun.
(2) if it is coal drop pipe blockage or the original coal bunker not bottom, should try to be unblocked. Such as coal is caused no coal should be quickly.
(3) if the coal feeder fault, should eliminate the fault quickly. If a short period of time can't restore, should stop coal mill run.
Steel cylinder block coal mill coal (full) from time to tome what phenomenon?
Coal mill block coal or coal, full air circulation section decrease or impassability, steel ball buried in coal, coal almost lost ground. Can show the following phenomena:
(1) coal mill entrance pressure difference increased, the entry negative pressure decrease or positive pressure, export pressure increase;
(2) the coal mill outlet gas powder mixture temperature drop;
(3) the coal mill entrance positive pressure, will make them take powder;
(4) the coal mill cylinder body noise reduction;
(5) the coal mill, the mechanical and electrical flow decreased;
(6) row of powder machine export lower air pressure.
How to deal with when the steel cylinder block coal mill?
(1) decrease or stop to coal, appropriate to open big smoke powder mill inlet damper top, at the same time pay attention to monitor the coal mill entrance pressure difference and the change of the exit temperature, when the inward and outward differential pressure returned to normal, should be immediately to the coal or coal.
(2), such as the lack of air as a wind, should be appropriate increase system ventilation rate, or start standby powder machine, in order to maintain a wind pressure.
(3) if the inlet pipe has been blocked, can be hit or open to the inspection hole opening, but must be done to prevent spray outward security measures.
(4) the above treatment is invalid, should stop running mill and switch the wind road, and then open the gateway manhole door check processing mill.
Coal mill inlet caused by deposition of coal burning main phenomena:
(1) coal mill outlet temperature, at the entrance to the smell of soot;
(2) the coal mill inlet negative pressure decreases, and the coal pulverizing system around the air pressure is not stable;
(3) coal mill inlet temperature, serious when inlet pipe blow-up burned red, explosion door.
The processing points as follows:
(1) cut off the interlocking, increase to the coal, and to use the new coal fire pressure;
(2) the pressure back to powder pipe gas lock device, so that they don't move, so as not to return to coal mill meal, and the fuel combustion;
(3) stop coal mill, the switch wind road;
(4) to open the entry inspection hole, take measures to put the fire out, but it is important to pay special attention to the personal safety;
(5) confirmed after fire extinguishing thoroughly, restart the coal mill.
