Abstract: This paper introduces the collection method of water sample in coal mining face and the general value of solid weight ratio. By analyzing the wear and tear of the solid particles on the balance disc, a simple and easy way to prolong the service time of the centrifugal pump is introduced. A new multistage sediment submersible pump for removing the balance disc for conveying the solid particles is introduced. Keywords: mining centrifugal pump to send off the balance plate suspended sediment submersible pump 1 Introduction At present, coal mining face drainage pump used in the row of sand products is a blank row. No matter how much sediment, commonly used is still the traditional multi-stage sub-level centrifugal pump. Therefore, serious wear and tear, pump premature retirement, not only increased costs, but also often directly affect the production schedule. As coal mining face and heading face can not be set separately sediment sediment silos, sand and other solid particles can not be removed in situ, so to solve the problem of using "clean water pump" sediment discharge, the only temporary To improve the performance of wearing parts to think of ways to achieve the final drastic changes in the structure of the drainage pump big fuss. Professional research work in this area has lasted for many years and is still under intense work. The study found that solid particles on the centrifugal pump wear, in a particular environment, to comply with a certain law. To show this law in front of us, the right medicine, we can find a better solution. 2 face water samples collected by the determination of solid weight ratio Observed, gushing coal mining surface, the content of solid particles with the recovery cycle changes in the contents of the operation, therefore, has a cyclical. Under normal circumstances, before the end of mining preparation, coal mining operations began, the least solid particles. Coal mining is about the end of the content. When collecting water samples, in order to reduce the number of acquisitions, but also to explain the problem, can be collected within 30 minutes before the official mining, mining once again within 30 minutes before the end of the mining operation. Collecting water samples at the coal mining face under the head, or in the slip-road installation of the pump's own separate outlet. In general, in the gushing water of the rock drift driving face, the solid particles content is the least before the multiple drilling machines concentrate the drilling. After blasting, solid particles were the most abundant in the last third of rock-out operations. Water samples were collected during these two periods. The collection site is within 10m after the working site of the scraper or rock loader or the drainage outlet of the drain pump at the working surface. The water samples collected above, each weighing 2K0.2kg. Weigh the weight, the use of filtration, filter out all the solid particles in the water sample with filter paper. After drying, weighed out the weight of the solid particles, then the water sample solid weight (percentage) ratio Caw: solid weight Cow = --------------- H% solids, the total weight of the liquid mixture The solid weight ratio Caw of water samples is defined as "weight solids concentration" in "Slurry and Granular Material Conveying Hydraulics" (published by Huaxiang University Press, May 1994) and is customary for conveying Industrial slurry. This article referred to as solid weight ratio, the scene sometimes used to call the sediment weight ratio. Under normal circumstances, when the gushing water of a working face is less than 10m3 / h, the solid weight ratio is obviously increased; the gushing water is more than 80m3 / h, and the solid weight ratio Cw is obviously reduced in the same mine. In a large number of water samples collected, we can get the mine gushing water solids in the general rule. According to the influx, the characteristics of rock and the degree of fragmentation, the reaction of loose particles with water after further analysis and sorting, it can be used to guide drainage design and drainage management. Table 1 is a comprehensive set of data obtained from the field. Table 1 Coal mining face excavation face (coal mining is about to end before) (rock production is about to end before) Solid weight ratio Cw 0.83-5.48% 0.41-9.62% 3 Multistage centrifugal pump wear parts and wear 3.1 More Centrifugal pump wear parts At present, mine multi-stage centrifugal pump wear the most serious parts of the balance plate, followed by the impeller port ring, packing sets, the middle of the shaft bore bushing. General solid particles will not wear the pump casing, will not wear a small diameter wheel, it will not wear short leaves. Balance plate wear thinning, the rotor to the motor direction (forward) channeling overrun, resulting in chain damage. After the impeller mouth ring and middle sleeve wear, the sealing gap becomes larger, so that insufficient or no centrifugal pump water, and sometimes mixed with a strong vibration. 3.2 Balance plate wear process Equalizer plate has an axial end beating, pump body balance plate also axial end beating. Balance plate rotation for a week, will turn to a certain angle, the local maximum axial clearance gap or minimum clearance. The equilibrium state of the balance disc is dynamic, and the pump rotor pulsates axially before and after a certain equilibrium position. When the operating point changes, the rotor will automatically move to a new equilibrium position for axial pulsation. After the axial end face beating and axial pulsation superposition, the axial clearance b0 has the local dynamic maximum clearance b0max and the minimum clearance b0min. Assuming that the particle diameter of a solid K is A, the solid K will be entrained by the liquid in the axial clearance of the balance disc from near the maximum axial clearance b0max as the liquid reaches the high pressure zone in front of the balance disc, and b0max> A> b0min within. When the solid K has just stepped over a small distance S, the balance disc is shifted to the position where the axial clearance b0 is smaller than A, or the balance disc is being pushed back to a position where the axial clearance b0 is smaller than A. FIG. At this time, the balance plate will squeeze the solid K, the two will be relative movement. The balance disk end will be pushed out of the indentation by the solid K and will be scraped out of the recess until the solid K is ground. If the specifications of the high content of solid particles, will be in line with the trend of the past, continue to be wrapped in, so that balance plate soon appear the first ring groove. As the abrasion aggravates, the second groove and the third groove will appear one after another slightly larger than the first annular groove. In spite of this, when the pump shaft channeling amount has not changed significantly, remove the balance disc can be seen that these annular grooves are generally concentric, arranged neatly. At the same time, a similar groove appears in the balance board. The following phenomenon is noteworthy: when the particle diameter of the other solid W is B, the high pressure zone of the balancing disk is reached, and if B≥b0max, the solid W will be blocked on the high pressure side of the balancing disk. At this moment, if the solid particles of different sizes are flocking to the high pressure zone in front of the balance disc, solid particles with a particle diameter of less than or equal to A will flow through the axial gap with the liquid flow. Solid particles with a diameter greater than or equal to B will be separated here. We call this phenomenon "sieving phenomenon." When a certain amount of solid particles are "screened" and blocked at the entrance to the axial gap, the pressure of the liquid will increase, causing the rotor to pulsate backward, causing the axial gap to increase momentarily. At this time, these large particles of solid particles took the opportunity to squeeze a large number of balance disc axial gap, a "strong landing phenomenon." If this happens one after another, the balance pan can be thinned in a short period of time. 3.3 The wear process of the impeller mouth ring Small impeller mounted to the pump shaft, the mouth ring there is a radial runout; pump mouth ring hole radial runout also exists. Impeller rotation a week, will turn to a certain angle, the local mouth ring radial gap maximum gap or minimum clearance. Rotating shaft will bend, resulting in maximum deflection. After the radial runout and the maximum deflection are superimposed, the radial clearance b of the mouth ring has a local maximum dynamic clearance bmax and a minimum clearance bmin. Similarly, the sealing surface of the mouth ring will also be squeezed by the solid particles, scraping out of the groove. However, if the material is the same, the wear of the collar is significantly less than that of the balance disc because the mouth ring gap does not "pulsate" like the balance disc and "strong landing" of the solid particles. At this moment, the wear of the mouth ring is not the main contradiction compared with the balance disc. However, it should be noted that in a multi-stage pump with unbalanced discs, wear of the orbital ring will rise as the main contradiction and must be taken seriously.
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