The invention provides an underground
coal mine fracture sealing device and method. The underground
coal mine fracture sealing device comprises a water injection
pipe, a thick liquid return
pipe, a front
polyurethane hole sealing section, a back
polyurethane hole sealing section, a
safety valve, an umbrella type supporting device
assembly and a thick
liquid injection pipe. The umbrella type supporting device
assembly is composed of an umbrella supporting frame, a supporting pipe, a sliding hoop, a
piston rod and a
piston, and a guide rail groove and the
safety valve are arranged on the supporting pipe. When being fed into a
drill hole, the umbrella type sealing device shrinks, and then the device is conveniently fed into the
drill hole. When high-pressure water of which the initial
injection pressure is 5MPa is injected, the umbrella type supporting device is opened, the
piston is pushed forwards, the umbrella type supporting frame is unfolded and penetrates into
coal, the high-pressure water continuously squeezes the hole sealing sections, and then the umbrella type supporting frame penetrates into the coal deeper and deeper. When the water
injection pressure is increased to be larger than or equal to 15MPa, pressure water breaks through the
safety valve to carry out fracturing operation on the
drill hole, and therefore pressure loading capacity of the hole sealing sections is greatly improved, water
injection pressure is increased, and the fracturing effect is improved. The underground coal mine fracture sealing device is simple in structure, easy to operate, high in pressure loading capacity, and good in sealing effect.