高性能自容式下井计的研制

介绍了基于 89C2 0 5 1单片机、溅射金属薄膜压力传感器、AD7714、DS18B2 0和AT 4 5D0 81A研制的高性能自容式下井计 ,论述了其工作原理、硬件电路设计及系统软件设计。该仪器可广泛应用于测量工作温度 - 4 0～ 85℃ ,工作压力 60MPa以下的各种流体介质的压力。

A new design of foam spray nozzle used for precise dust control in underground coal mines

In order to improve the utilization rate of foam,an arc jet nozzle was designed for precise dust control.Through theoretical analysis,the different demands of foam were compared amongst arc jets,flat jets and full cone jets when the dust source was covered identically by foam.It is proved that foam consumption was least when an arc jet was used.Foam production capability of an arc jet nozzle under different conditions was investigated through experiments.The results show that with the gas liquid ratio(GLR)increasing,the spray state of an arc jet nozzle presents successively water jet,foam jet and mist.Under a reasonable working condition range of foam production and a fixed GLR,foam production quantity increases at first,and then decreases with the increase of liquid supply quantity.When the inner diameter of the nozzle is 14 mm,the best GLR is 30 and the optimum liquid supply quantity is0.375 m^3/h.The results of field experiments show that the total dust and respirable dust suppression efficiency of arc jet nozzles is 85.8%and 82.6%respectively,which are 1.39 and 1.37 times higher than the full cone nozzles and 1.20 and 1.19 times higher than the fiat nozzles.

A new design of foaming agent mixing device for a pneumatic foaming system used for mine dust suppression

To overcome the drawbacks of the conventional foam technology used for dust suppression,including large pressure loss,high water pressure and low driving pressure,a new pneumatic foaming system is introduced.Then an original design of foaming agent mixing device is proposed,and its performance is investigated and evaluated under different pressure compensations.Experimental results show that the maximum absorption amount increases by 2.9-6.7 times at a pressure compensation of 0.04-0.2 MPa compared with no pressure compensation.The pressure loss and pressure fluctuation both reduce significantly with increasing pressure compensation.The critical outlet pressure increases by30.4-240%.Field application indicates that the proposed mixing device ensures the reliable addition of foaming agent used for foam dust suppression.The effect of foam on dust suppression is remarkable,and the economic cost of foam is low.Therefore,there is reason to believe that the new mixing device will greatly promote foam technology to be widely used for suppressing dust in underground coal mines.

Design and performance analysis of wireless sensor network location node system for underground mine

Aiming at the application of a wireless sensor network to locating miners in underground mine,we design a wireless sensor network location node system,considering the communication performance and the intrinsic safety. The location node system consists of a mobile node,several fixed nodes,and a sink node,all of whose circuits were designed based on CC2430. A varistor and a RC circuit were used in the reset circuit of a sensor node to guarantee the intrinsic safety by reducing discharge energy,the theoretical analysis of the discharge energy shows that the reset circuit is an intrinsic safety one. The analysis and simulation about the performance of the location node system are discussed,such as network communication delay and packet loss rate,the results show that the highest network communication delay of the system is about 0.11 seconds,and the highest packet loss rate is about 0.13,which assures the location node system has a high reliability,and can locate miners in the underground mine.

Fundamental behaviours of production traffic in underground mine haulage ramps

Ramps(or declines) are often used in underground mines to transport ore, waste, materials, and personnel. This paper studies mine ramp productivity and presents results from a set of computer simulations designed to model the fundamental behaviours of ramp haulage systems. Simulations show that, under fundamental assumptions without random disturbances, the haulage system always converges to a periodic behaviour in the steady state, but that productivities vary between equilibria. Simulations also demonstrate how productivity per vehicle does not necessarily decrease as more vehicles are added and,for example, in the five-vehicle case, how a 3.1% improvement can be achieved over the use of four vehicles. The result reveals the inefficiency of commonly-used lockout-style vehicle coordination strategies,and suggests a possible avenue for improving the productivity of haulage ramps by controlling the system to achieve more productive behaviours.

Design and Implementation of Remote Control System of Coal Mine Conveyor Belt based on PLC

Aiming at the existing problems of safety, reliability and flexibility in the traditional coal mine belt transport system, this paper designed the mine centralized control system transmitted by CAN bus and PLC as the core, and use comparison instructions and trigger of Siemens S7-200 PLC, the article has elaborated the four level conveyor belt sequence control, realized the sequence start, reverse sequence stop and fault processing and other functions for four level conveyor belt, the compared with traditional timer control instructions scheme, the design has clear thinking, simple design program, and is easy to be extended to multilevel belt drive sequence control.

Design and implementation of coal mine safety management system based on Ajax and RFID

This paper describes the design and implementation of a coal mine safety management information system based on Ajax. The whole system includes two alarm processing subsystem and management subsystem. Alarm processing subsystem in the server, used to analyzed monitoring data of underground mine, judged whether it is in an abnormal state, also including the crews time recorded by RFID, so that timely alarm data is written to the database for the use of management infonlaation system; management information system adopts the three layer system structure based on B/S, the client the use of ax technology for an asynchronous request to the server, the server operation backstagc Oracle database to complete the business logic processing, and the results in XML form and return it to the client, the subsystem to the user to provide an interactive platform, users can monitor the underground state in real time, at the same time when the abnormal status, the system can timely alarm, prevent the occurrence of coal mine accidents.