Gear pump selection of the general procedure: 1, according to the layout of the device, topography, water conditions, operating conditions, economic programs and many other factors. 2, consider the choice of horizontal, vertical and other types (pipe, right angle, variable angle, angle, parallel, vertical, vertical, submersible, demolition, Self-priming, gear-type, oil-filled, water-filled temperature). Horizontal gear pump disassembly easy to assemble, easy to manage, but bulky, the price is more expensive, requiring a large footprint; vertical gear pump, in many cases the impeller submerged in water, can be started at any time, to facilitate automatic ç› or remote control , And compact, small installation area, the price is cheaper. 3, according to the nature of the liquid medium, hydraulic gear pump to determine the water gear pump, hot water gear pump oil gear pump, chemical gear pump or gear pump corrosion resistant gear or impurities, or high pressure gear pump or non-clogging gear pump. Gear pumps installed in the explosive area should be explosion-proof motor according to the explosion area level. 4, the vibration is divided into: pneumatic, electric (electric divided into 220v voltage and 380v voltage). 5, according to the size of the flow, single suction gear pump or double suction gear pump: According to the level of the head, suction pump gear suction pump or more suction gear pump, high speed gear pump or low speed gear pump (air conditioning gear pump), multi-stage gear pump efficiency Lower than the single-stage gear pump, when the single-stage gear pump and multi-stage gear pump can also be used when the same, should use a single-stage gear pump. 6, Determine the specific type of gear pump, the use of what series of gear pump selection, you can press the maximum flow, amplification of 5% - 10% head lift after the main performance of these two parameters in the spectrum or series of features Curve to determine the specific model. Use the gear pump characteristic curve, find the required flow value on the abscissa, find the desired lift value on the ordinate, draw the vertical line or the horizontal line from the two values ​​respectively upward and right, the intersection of two lines just falls on the characteristic curve, The gear pump is the gear pump to be selected, but this ideal situation is usually not rare, usually encounter the following situations: A, the first: the intersection point in the characteristic curve above, indicating that the flow to meet the requirements, but Head is not enough, this time, if the head or less, or a difference of about 5%, can still be used, if a lot of head difference, then choose larger head gear pump. Or try to reduce the pipeline resistance loss. B, the second: the intersection of the bottom of the characteristic curve, gear trapezoidal fan gear trapezoidal range, the initial set under this model, and then according to how much head difference, to decide whether to cut the impeller diameter, if the difference is small head, not Cutting, if the head is very different, according to the required Q, H, according to its ns and cutting formula, cutting impeller diameter, if the intersection does not fall within the range of fan-shaped trapezoidal, should choose a smaller lift pump gear. Select gear pump, sometimes have to consider the production process requirements, choose different shape QH characteristic curve.