(1) When the high pressure inflation mode is adopted, the effective volume of the air chamber of the extrusion pipe can be calculated as follows:
Where V—the effective volume of the air chamber, m 3 ;
P———the rated working pressure of the pump, kPa;
V P ———the air volume of the air chamber, m 3 ;
β———remaining volume factor, generally taken as 0.042;
F———the piston sectional area, m 2 ;
S———piston stroke, m;
δ———pressure unevenness coefficient.
(2) When using low pressure inflation, the effective volume of the air chamber of the extrusion pipe can be calculated as follows:
Where P s ——— pre-filled air pressure, kPa.
(3) The effective volume of the suction tube air chamber can be determined as follows:
V≥5FS~10FS (26)
Where V—the effective volume of the air chamber, m 3 ;
Other symbols are the same as before.
(II) Configuration of pumping station A Principle of site selection of pumping station (1) Try not to use underground type to save investment and reduce the amount of earth and stone;
(2) The location of the pumping station should be convenient;
(3) Areas where engineering geological conditions are poor or are easily washed away by floods should be avoided;
(4) The pipeline slurry in the pumping station should have the possibility of self-flow and efflux when an accident occurs.
B. Principles for determining the dimensions and height of the pumping station The dimensions of the pumping station are determined by the following conditions:
(1) To meet the needs of installation, overhaul and production operations of slurry pumps, water seal pumps, drainage pumps, lifting equipment, power distribution equipment, etc.;
(2) The floor space required for material stacking, worker rest, and other ancillary facilities should be considered;
(3) To take care of the requirements of building modulus. The channel width between units in a pumping station generally has the following requirements:
(1) When there is lifting equipment and there is centralized maintenance site, the low-voltage motor units should not be less than 1.2 meters; the high-voltage motor units should be no less than 1.5 meters;
(2) When there is no lifting equipment or lifting equipment without centralized inspection site, it should be greater than the width of the pump unit by 1.5 meters;
(3) The unit extends beyond the foundation, and the width of the passage between them is generally not less than 1.2 m; the width between the extension and the wall is not less than 0.7 m;
(4) The width of the channel in front of the low-voltage switchboard shall not be less than 1.5 m; the high-voltage switchboard shall be provided with a partition wall spaced from the machine. The effective height of the house in the pumping station is determined by the net space between the bottom surface of the largest component of the crane and the top surface of the required span. The spacing is generally required to be not less than 0.5 m; and the minimum effective height of the general pumping station should be 3.2 m or more. The height of the underground pumping station needs to be determined according to the production needs and equipment loading and unloading requirements, but usually the height of the upper part of the pumping station should not be less than 3 meters.
In order to prevent the distribution equipment from getting wet or damaged due to the flow of the floor water in the pumping station, the ground level of the distribution room should be slightly higher than the ground level between the pump units, which is roughly 0.15-0.3 meters higher. [next]
C slurry warehouse (pool)
The slurry bin (pool) is an important part of the slurry pumping station. It can stabilize the displacement and the pressure of the pump to ensure the normal production of the pumping station.
According to the slurry mode of the pump, the slurry bin can be divided into two types: suction type and press type. There are production examples for both types, but there are more press-fits. The pulp silo can be located indoors or outdoors, depending on local climatic conditions or management needs. However, large ore pulp warehouses are mostly located outdoors.
The pulp warehouse should generally be divided into several grids corresponding to the pumping station (group), but some pumping stations need to change the pulp warehouse in order to reduce the switching pump group, and several (group) pumps are used together to form one pulp warehouse. This type of slurry bin should take into account measures that will not affect the normal production of the pump set when cleaning or overhauling the pulp tank.
The determination of the volume of the slurry bin depends mainly on the fluctuation of the amount of the ore. The volume of the slurry tank of a single centrifugal slurry pump should meet the lifting capacity of 1 to 3 minutes. The volume of the slurry tank shared by multiple pumps should be determined according to the number of pumps that are simultaneously activated and the amount of pumping from 1 to 3 minutes per pump. The volume of the slurry tank of the oil isolation mud pump should generally be no less than 10 minutes. The slurry with particle size or concentration adjustment is required before transportation, and the volume of the slurry bin should be determined according to the process needs.
The inner bottom slope of the slurry silo facing the discharge port should generally have a slope of 1:1 to 1:4, so that the slurry can be easily flowed to the discharge port, and a flushing water pipe and an accident discharge port should be provided. If necessary, a stirring device should be installed in the warehouse.
D Piping arrangement in the pumping station a General requirements for piping arrangement (1) The slurry pipeline arrangement in the pumping station should first consider safety production. When a pump group, pipeline, gate valve, or pipe fittings fails, the normal production of the pumping station must be guaranteed;
(2) To simplify the layout of the pipeline and reduce the number of pipe lengths, bends and gate valves, it is necessary to avoid dead spots;
(3) It is necessary to take care of the convenient transportation in the plane and vertical direction of the pump station;
(4) In order to reduce the labor intensity of the staff, large-size gate valves should be operated by hydraulic or electric power as much as possible.
b Several layouts of slurry pipelines in pumping stations The typical piping layouts of several centrifugal slurry pumping stations are presented here. The oil-isolated mud pump station is not very widely used in China, and there is no systematic summary of the pipeline layout in the pump station. Therefore, the configuration of the Hunan Tin Mine oil-isolated mud pump pump station is described in the following manual (Figure 4). reference. From the point of view of the oil-isolated mud pumping station that has been put into production, the piping layout has many similarities with the centrifugal pumping station.
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E Pumping station auxiliary equipment and auxiliary facilities Pumping station auxiliary equipment mainly includes power distribution equipment, lifting equipment, communication equipment, water supply and drainage equipment and necessary measuring instruments. At the same time, maintenance sites, equipment warehouses and workers should be set up according to need. Room, auxiliary facilities such as heating and ventilation. It is now described as follows:
the reliability of a power distribution equipment for the pumping station is not lower than the main beneficiation plant production workshop. The power supply and distribution equipment capacity should meet the characteristics of pump performance adjustment and the need for pump performance changes that may occur before and after production. At the same time, it is also necessary to consider the use of electricity.
The power distribution equipment and the pump unit should be strictly separated. When the two are installed in the same building, the spacing should be kept above 2 meters. Lighting facilities for work and maintenance should be provided inside and outside the pumping station, in the slurry warehouse, in the accident pool, etc.
b Lifting equipment c Communication equipment should have a dispatching telephone between the main slurry pumping station and the plant dispatching room. Whether there should be a dispatching telephone between each pumping station and the dispatching room should be determined according to the actual needs of each production plant; A dedicated direct telephone should be installed in the station. Large pumping stations or small and medium-sized pumping stations with multiple pumps should be considered for setting up telephone soundproof rooms.
d Water supply and drainage facilities and equipment The water supply pipeline should be installed in the pumping station to supply water for various purposes, such as adjusting supplementary water, flushing pipeline water, water sealing water, flushing floor water, etc. The water supply can be directly from the external pipeline. When the water supply pressure is too low to meet the production needs, various special water supply pumps (pressurized pumps) can be set. Except for the water seal pressure pump, the other types of water supply pressure pumps need to be Set up an alternate, depending on the situation.
The water-sealed water supply of the centrifugal slurry pump should be 1-2% of the slurry transport volume (the large pump takes a small value; the small pump takes a large value). The water seal water supply pressure should be 196 kilopascals larger than the slurry transport pressure (ie 2 kg / cm 3 ).
The water supply capacity of the flushing pipe should be determined according to the flushing requirements of the slurry pipe. Generally, the flushing water volume should not be lower than the critical flow rate of the conveying slurry; the flushing water volume of the pipeline which is not required for flushing can be reduced as appropriate.
In addition, it is necessary to supply domestic water to the pumping station; the pumping station with the oil-isolated mud pump is required to supply water for adjusting the oil level of the oil tank.
In addition to the above requirements for water pressure, the water pressure of all other water points should be 98.1 kPa (1 kg / cm3). The water quality requires clean water.
The amount of water discharged from the pumping station is generally small, and most of it is intermittent drainage. Therefore, the pumping station floor should have a certain slope (generally 0.01 ~ 0.02), so that waste (sewage) water can be discharged from the flow; if there is no self-discharge condition, vertical, self-irrigation horizontal, or submersible drainage pump can be set A ejector can also be used.
e Measuring instruments The slurry tank should normally be equipped with a level indicator. The necessary alarm devices, measuring displacement, working pressure, temperature, pH, concentration, etc. should be installed in the pumping station. These facilities or meters should be installed in a location that is easily viewable by the staff.
f Others There are many other contents, and the pumping stations are often not necessarily the same. In summary, the following items need to be considered:
(1) Pumping stations should consider measures such as prevention of water hammer and accident handling in the event of an accident;
(2) Set up maintenance sites, equipment warehouses, waste dumps, workers' lounges, necessary roads and transportation facilities;
(3) The minimum temperature in the pumping station should be kept above +5 °C. For the pumping stations that may freeze in winter, antifreeze should be considered;
(4) When the pumping station unit has a large capacity, transporting pulp with special odor, or conveying high-temperature pulp, the pumping station should consider the necessary ventilation measures;
(5) The oil-isolated mud pump generally adopts No. 22 turbine oil, and there are two ways of supplying oil to the fuel tank: manual oil pump is more suitable for the number of pump units, when the fuel consumption is small, otherwise, the fuel pump should be set;
(6) The oil isolation mud pump air chamber can be inflated by high pressure or low pressure method. However, due to the low pressure method, it is necessary to stop the pump from inflating, so most of the current methods are high pressure inflation. The pneumatic pressure should be greater than the high pressure pump pressure 294 to 490 kPa (3 to 5 kg / cm 3), disposed generally need to consider the compressed air supply unit;
(7) Oil isolation mud pumping station should consider setting up safety protection devices to prevent motor burning or pipe bursting.
