ANSI 150LB Globe valve also known as the door valve, belongs to the forced sealing valve, so when the valve is closed, must apply pressure to the disc, in order to force the sealing surface leakage.When the medium under the disc into the valve, the operating force to overcome the resistance, is the friction of the valve stem and packing and by the pressure of the medium produced by the thrust, the force to close the valve is greater than the force to open the valve, so the diameter of the valve stem to be large, otherwise the valve stem bending fault will occur.