Application of Meishan Science & Technology Diaphragm Pump in Tailings Transportation and Improvement Ni Jian 's Problems and Improvements .

1 Introduction Meishan Iron Mine is used for underground mining. After the ore is coarsely broken by the well, the particle size is 0300mm and enters the concentrator. After being crushed, crushed and sieved, the grain is sized to 75 4 grains. 7512mm re-election tailings and 122mm magnetic separation tailings were sent to waste rock silos via belt conveyors. Wet tailings after 20-50mm magnetic separation and re-election were re-evaluated for tailings. After the 120mm coarse concentrate was ball milled, the grain size was 72% with 200 meshes. After the flotation desulfurization and dephosphorization by magnetic separation, the tailings produced were fed into the large-scale tailings of phosphorus reduction tailings. The re-election tailings and phosphorus-reducing tailings slurry are mixed and concentrated to form a slurry with a particle size of 20 mm, a concentration of 25% and an iron grade of 24%, which is fed through a high-grade slurry tank as a diaphragm pump; Meishan Concentrator transports the tailings The diaphragm pump used is produced by Shenyang Nonferrous Machinery General Plant. The conveying distance is 12.5km, the conveying pressure is 4.2MPa, and the design final delivery pressure is 6.5MPa. The frequency of the inverter is set at 4042Hz in the summer, and the flushing time of the diaphragm pump is at 30r. /min; around the frequency of 4650Hz in winter, punching about 38r/min.

2 Development of Diaphragm Pumps With the development of industrial technology, people have been devoted to the research and development of the delivery and injection of solid and liquid mixtures. The science involves fields such as metallurgy, mining, non-ferrous metals, coal, chemicals, building materials, and environmental protection. Among them, the abrasive slurry has a long history of transportation. It has used reciprocating piston pumps, oil isolation mud pumps, water isolation pumps, and flushing pumps. However, the biggest drawbacks of these pumps are the low continuous operation rate, high operating cost, and high labor intensity of operation and maintenance, which results in a decrease in the production efficiency of the entire process system and an increase in production costs, thus restricting the development of this field. With the advancement of technology, the wear resistance, pressure, temperature, continuous operation rate and other indicators have become more and more demanding. The above pump types can no longer meet the requirements of various production processes. It is urgent to change this situation as soon as possible.

In 1958 the French scholar Ballu applied for a patent for the piston diaphragm pump structure. Because it combines the advantages of high piston pump pressure, durability, diaphragm pump structure, corrosion resistance and other advantages, it overcomes the lack of easy wear of the piston pump seals, so soon Accepted by people. Developed countries in Europe will invest their energies in the development of piston diaphragm pumps and become self-contained. The GEHO diaphragm pump from HOLTHUIS, with advanced technology, is suitable for corrosion and slurry transportation. It is representative. The pump has been widely used in coal, chemical, iron ore concentrate, slurry transportation, alumina and many other fields, Germany and Canada have also developed a diaphragm pump of the same design style. In this way, the piston diaphragm pump of this system basically occupied the market of highly corrosive slurry transportation and represented its development direction.

In the 1980s, our country introduced the reciprocating piston diaphragm pump (hereinafter referred to as the diaphragm pump) of the Netherlands HOLTHUIS company in the Bayer process dissolution system of alumina, and its use effect was very satisfactory. However, the introduction of the pump is expensive. Take Shanxi Pingguo as an example, the flow rate of 450m3/h, the pressure of the diaphragm pump with a pressure of 6.5 MPa is 50 million yuan, and the cost is 500,000. From an economic point of view, it is not possible to replace the oil isolation mud pump operated in the alumina firing process system.

China began to develop a diaphragm pump from the early 90s. Shanghai Dalong Machinery Factory, Lanzhou Petroleum Machinery Plant, and Shenyang Nonferrous Machinery Plant have successively developed and produced diaphragm pumps.

3 The structure and working principle of the diaphragm pump were installed, and trials began in April.

3.1 Structure The SGMB140-7 diaphragm pump is composed of transmission system, power end, hydraulic end, control system and hydraulic auxiliary system.

The drive system is mounted on the base of the welded structure by the main motor and reducer. The mounting surface of the base is machined to ensure the alignment of the motor and reducer. The main motor shaft and the reducer are connected through the flexible coupling. The output shaft of the reducer and the drive shaft of the power end are connected via a toothed coupling.

The power end is composed of a box body, a transmission gear, an eccentric wheel, a connecting rod, a crosshead, a medium rod, and the like.

The hydraulic end is mainly composed of a fuel tank, a diaphragm chamber, a box valve, a feed pipe, a discharge pipe, a pressure compensator for inlet and outlet materials, and the like.

Control system control items are: diaphragm position control: diaphragm breakage detection, working pressure relay, air pressure relay, propulsion hydraulic pressure relay, shaft end protective cover limit switch, propulsion liquid pump motor, rinse liquid motor, power end lube oil pump motor , Lubricating oil pump motor and its main motor.

The above control items are completed by a PLC and interlocked with each other.

The hydraulic auxiliary system includes a propellant system, a power end lubrication system, a reducer lubrication system, a flushing system, an exhaust system, an overpressure protection system, and a pressure gauge unit. Through the normal operation of each system, the normal operation of the equipment is ensured.

3.2 Working principle The working principle of the SGMB140-7 diaphragm pump is shown in the figure. The motor drives the eccentric wheel, connecting rod and crosshead through the speed reducer, so that the rotation motion becomes linear motion and drives the piston to reciprocate. When the piston moves to the left, the slurry is sucked through the feed valve. When the piston moves to the right, the piston pushes the diaphragm to the right by means of the oil medium, while the pulp is conveyed to the pipe through the discharge valve. The diaphragm pump has four diaphragm chambers. The initial discharge phase of each diaphragm chamber is separated by 90°, which can make the slurry convey evenly. The working principle of the diaphragm pump is shown in the figure. A piston cylinder; 2-guide rod; 3 4 diaphragm pump is running The following problems existed in the problems and improvement operations. After corresponding improvements, satisfactory results were achieved.

During the test run, the friction between the piston rod and the stuffing box of the fuel tank was severe. A new oil pipe from the lubricating oil pump is used to spray the piston rod for better lubrication.

Zhejiang Xiangshan Solenoid Valve Factory and Wuxi Solenoid Valve Plant's two-way three-way solenoid valves are flat-type seals.

Under 6MPa pressure, leakage is serious. Afterwards, Germany imported cylindrical two-position three-way solenoid valves instead of domestic solenoid valves to meet production requirements. Imported solenoid valve is 2000 yuan a, the use of more than 6 months, domestic solenoid valve is about 50 yuan a Ni Jian: The application of diaphragm pump in the tailings transportation and improvement of Meishan science and technology, the yield is about 10%, the use period is generally One month.

(3) The check valve structure of the diaphragm cavity replenishment system is unreasonable. The one-way valve adopts the interference of the copper washer and the steel valve seat, and the nylon valve stem and the copper washer contact to achieve the sealing effect.

Since the one-way valve is subjected to a pressure of 1.5 MPa, the interference between the individual copper gasket and the valve seat is insufficient, and the copper gasket is disengaged, causing the energy storage device to pass through directly to the diaphragm chamber and the large diaphragm is broken down. Through analysis, it was decided to cancel the copper gasket. The entire one-way valve was entirely made of steel. After several months of use, there was no problem.

Diaphragm pumps have a great impact during the working process. After several months of operation, the connecting rods of the piston rod and the intermediate rods are loosened. After being found at the scene, they are tightened and loosened after several classes. After analysis and research, the lock nut was modified to make a special fastening tool, increase the pre-tightening force, and increase the lock-resisting washer, which was not loosened later.

Membrane pump power end bearing seat bolts and nuts are made of split pins to prevent loosening, the bolts are connected to the base and a M12 bolt is used on the side to prevent loosening. Due to the vibration generated by the diaphragm pump itself, the bolts of the M12 loosen and fall off at first, which causes loosening of the connection between the fastening bolt and the base. The split pin does not work. Through inspection and analysis, the bolts of M12 were punched at the tail, perforated with 14 wires to prevent loosening, and the locking washers were used to replace the split pins. After one month of operation, there was no loosening and the effect was satisfactory.

In the past more than one year, the equipment has been running smoothly and reliably, meeting the production requirements, and basically meeting the design requirements of the second and the second.

5 advantages and disadvantages of the diaphragm pump 5.1 advantages of smooth, low noise, few wearing parts, large diaphragm long life, maintenance and repair workload is small.

(2) The control system is more advanced, the diaphragm alarm has originality, and the pump's own protection performance is better.

(3) Adopting variable frequency speed regulation, the slurry transportation can be adjusted at any time according to the production process requirements, and the power saving effect is obvious.

5.2 Disadvantages (1) There is no cooling device in the power end tank and the hydraulic end tank. In the south, the summer temperature is low and the oil temperature is high. The oil drain hole is too big and the oil is not clean. It is difficult to clean the oil tank.

(2) Advancing the liquid oil pump and lubricating oil pump joints with poor sealing and oil leakage.

The price is more expensive.

The entire diaphragm pump price is relatively low, one-time investment is relatively large.

6 Conclusion After more than one year of production and use, the pump can meet the requirements of on-site production, providing a precedent for the use of domestic diaphragm pumps for metallurgical mines. Development of SGMB140-7 diaphragm pump. The work fills the gap in the medium pressure and large displacement of the domestic diaphragm pump. If a slight improvement is made in the design, a more reliable control element can be used to replace the imported diaphragm pump to some extent.

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