Proof door is one of the most important safety feature ventilation system, is particularly important. The author summarizes the work in practice, coal gas and coal dust explosion is the main cause great harm: blast doors does not work, because the deformation does not reset properly, causing a short circuit ventilation system, the main fan is not working. Explosive release of large amounts of toxic and harmful gases can not be discharged to the ground, C0 poisoning resulting in increased number of personal injury or death, resulting in expansion of the accident. After the transformation, improve the safety and reliability of coal mine air shaft explosion-proof doors, with some promotional value. Proof door is a special seal covers installed on the exhaust fan mounted main wellhead. During normal ventilation, it is used to isolate the underground and surface atmospheric flow, short circuit to prevent airflow to ensure normal ventilation systems. Once when underground gas or coal dust explosion, explosion-proof doors are open air shocks, thereby explosion airflow discharged directly into the ground atmosphere, play a relief role in preventing major fan blast of explosion caused damage; when the main When the fan stops running, you can open the blast doors, in order to take advantage of natural ventilation pressure. "Coal Mine Safety Regulations" Article 121 states: wellhead fitted with main fan must be closed tightly; equipped with main fan should be installed out of the wind blast doors wellhead. Article 124 provides that: The main fan stops running during the blast doors must open the wellhead and pressure related to the use of natural ventilation dampers. Current structure and status of the door there is a leakage-proof, open and close the difficulties, demands, and therefore need to be improved. An original proof door problems for field use by blast doors for research summary, the following problems: (1) Reset: Currently used mine explosion-proof door there is not work properly due to deformation can not be reset. (2) sealing liquid: liquid-proof sealing doors currently use more water seal, water easily evaporate once the seal water pressure is less than the level of negative pressure ventilation, water will suddenly absorbance, a serious leakage. Keep water, waste water will cause another fan drivers always look at the situation seal water, the impact of inspection tour and observe ventilator equipment operating conditions. In winter, because the water is easy to freeze, to choose not burning coolant, is more difficult to choose and use a cryogenic liquid. (3) the individual mine blast doors to prevent air leakage, and even blast doors sealed with cement, so that the door can not play the role of proof, endanger the safety of fans and ventilation systems. (4) Individual mine blast doors open after the fan stops running, the fan does not restart automatically shut down, the need to manually shut down, slow, affecting the normal operation of the ventilation system. 2 The new explosion proof door door design 2.1 design requirements (1) once produced gas explosion, explosion-proof door in time to reset, ensure that the underground ventilation system is working properly. (2) proof doors should be arranged on the same axis wind well, the basal area of ??not less than the well-off area out of the wind. Distance proof doors (3) out of the air shaft and tunnel crossing point into the wind than the point to the main fan suction outlet must be at least a short distance 10m. (4) by the main fan blast doors should be kept closed in the negative, and install counterweight to blast doors or taking other measures to facilitate the blast doors easy to open. Structure (5) blast doors must have sufficient strength, and has antiseptic and anti thrown facility. The new 2.2-proof design of the door (1) proof door type steel ring design and installation of steel in the wind around the wellhead installation on steel blast doors, sealed with rubber plate in the middle. Rubber plate with plate fixed on blast doors. Explosion outside rail installation 3, was 120 ° distribution, so that movement along the rail blast doors on the set limit, so open the door height is controlled explosion. There hydraulic positioning device on the blast doors to ensure timely and correct reset. Type rims wellhead in the wind as possible, ensure consistency with the wind wellhead section can be, this can reduce the force of the blast doors, blast doors because the force of the negative pressure type rim section and the product of the mine. K- factor of safety rubber sheet; contact with the blast doors type rims; width B≥Dhσ (KP4) formula; D- type rims in diameter; h- mine negative; rubber sheet allowable pressure. (2) to determine the weight balance weight: weight balance weights pull up as much as possible to produce equal or slightly greater than the weight of the weight of the door explosion-proof doors, when the main fan stops running, the natural pressure up to produce a upward force, blast doors can be opened to form a natural ventilation. When the main fan resume operation, due to the explosion of the door opening height H has a limitation, air inlet cross-sectional area smaller than wind tunnel cross-sectional area, (2) flows based on the Bernoulli equation pPγ + Z + v2P2gn = constant air inlet great speed, inlet pressure p less than atmospheric pressure, blast doors closed at atmospheric pressure. Proof door opening height H = DP4-C (3) C is determined by the actual practice, to find a reasonable value. C too, when the main fan stops running, the wind blast doors open section formed small, the impact of natural wind pressure ventilation; C is too small, when the main fan resume operation, due to the open door into the wind section of the formation of a large explosion , inlet pressure and atmospheric pressure p less, blast doors by small atmospheric pressure, can not close the blast doors. 2.3, the new features of the new explosion-proof door door improved by the use of design requirements, mainly has the following characteristics: (1), sealed with rubber seals, sealing wide, can be effectively sealed to ensure no leakage. Overcome volatile liquid and liquid-tight winter freeze problems, seasonal influence on the small seal, do not need to replenish fluids. (2) to overcome the liquid seal liquid for corrosion-proof doors. (3), blast doors open easier, balance weights for proof doors can be installed when lighter than the liquid seal, because the liquid seal, fans stop running, balance weights in addition to its own gravity to overcome the blast doors open when the blast doors , but also to overcome the force of the liquid in the liquid level inside and outside the blast doors produced. When the fan starts again can more easily close the damper. (4) maintenance, inspection convenient, less maintenance. 3, the Beijing-proof door manufacturers plus five new explosion-proof door to overcome the legacy door seal unreliable and subject to seasonal effects of the problem, maintenance, inspection easy to open and close, reliable, consistent proof door design requirements.