A pressure relief valve includes a bonnet threadedly secured to a pressure vessel, a floating device in the pressure vessel, a relief assembly, an actuator secured to the bonnet and communicating with the bonnet, a biasing element put on a stem and biased between a tubular member and a conic member, and a safety valve. The hollow cylinder is slidable in a space defined by the tubular member and a hollow, cylindrical actuating member. The stem is slidably disposed in the tubular member. Pressurized fluid enters a conic opening via an inlet connector, a first channel, a Venturi tube, and a second channel to push the tubular member so as to disengage a latch from a hook to release the pressurized fluid.