Design Of Integrated Multi-functional Emulsion Tank And Research On Emulsion Feeding Method

Emulsion feeding system supplies high pressure emulsion for hydraulic supports.Its rationality,reliability and efficiency are significant to the safety,reliability and efficient production.Nowadays,there are three main problems with emulsion feeding system:(1)Emulsion is not clear enough.(2)Single emulsion pump can't meet the large flow-rate demand of high-production and high efficiency coal face.(3)Emulsion feeding method is not economical and rational enough.This dissertation designed some emulsion feeding equipment and studied emulsion feeding process as well as emulsion feeding method to solve these problems.In order to improve the cleanliness of emulsion,the author designed an emulsion tank equipped with a multi-filter system which consists of a plate filter,inlet filter,high pressure filter,outlet filter and sewage filter.In this stage,the author also designed backwash self-cleaning principle and the filter element parameters of the inlet filter and outlet filter,then 3D-modeled this emulsion tank with Solid Works.As it mentioned before,single emulsion pump can't meet the large flow-rate demand of high-production and high efficiency coal face,so a liquid converging valve was designed to achieve multi-pump emulsion supplying and Fluent was employed to simulate and analyze the flow field of the liquid converging valve while one pump,two pumps and three pumps were working.The results indicate that the more pumps were working,the larger pressure drop presented when emulsion flowed through the liquid converging valve.Furthermore,the main pressure drop was led at the outlet of the liquid converging valve when two or three pumps were supplying emulsion.In order to design a more suitable diameter for the outlet of the liquid converging valve,the author analyzed its flow flied while three pumps were working under different outlet diameters(38mm,45 mm,50mm,60 mm etc.).This research shows that with the increase of the diameter,the pressure drop decreased remarkably when outlet diameter is below 50 mm,but it reduced slightly while the diameter enlarged from 50 mm to 60 mm.So it's more suitable to set the outlet diameter of the liquid converging valve with 50 mm.Aimed to improve the emulsion feeding method,the author also established the mathematical model of the emulsion feeding process and ran a simulation used AMESim to study the emulsion feeding process.In this work,the influence of different unloading pressure,different pressure difference between unloading and loading pressure,different capacity of hydraulic accumulator and different flow-rate on the emulsion feeding process was investigated.The result presents that unloading pressure,pressure difference between unloading and loading pressure,capacity of hydraulic accumulator exerted limited influence on the action speed of hydraulic supports,while increasing pressure difference between unloading and loading pressure or capacity of hydraulic accumulator can reduce the switching frequency of unloading valve effectively while supports were using less emulsion or didn't need emulsion supplying.On contrast,flow-rate has significant effect on the raising speed and setting load of hydraulic supports.The raising speed of hydraulic supports accelerates with the increasing of flow-rate when it is less than the practical flow-rate demand for raising hydraulic support operation.On the contrary,if flow-rate is larger than the practical flow-rate demand for raising hydraulic support operation,it not only couldn't speed up raising hydraulic support but also increases the switching frequency of unloading valve,as a result increases its failure rate and shorten its lifespan.However,flow-rate has little influence on the action speed of supports during descending supports,pushing forwards the conveyer and moving supports,because of the smaller emulsion demand and the effect of emulsion discharging of hydraulic accumulator,while if flow-rate is excessive,it also results in increased switching frequency of unloading valve.At last,the advantages and disadvantages of the main emulsion feeding methods were analyzed,and a new flow-rate matching emulsion feeding method based on the recognition of the support action was proposed.Then the author ran a simulation to compare this new emulsion feeding method with the emulsion feeding method based on unloading valve and constant pressure emulsion feeding method based on frequency conversion technology.The result indicates that the flow-rate matching emulsion feeding method based on the recognition of the support action not only combined the advantages of the emulsion feeding method based on unloading valve and constant pressure emulsion feeding method based on frequency conversion technology,but also avoided their disadvantages,and shown its reasonability and superiority.