Abstract: A gas pressure reducing regulator has a tied-diaphragm so as to obtain relatively complete valve closure even with corrosive gases that tend to deposit particulate matter on the valve seat and otherwise inhibit valve closure. Misalignment of the diaphragm with respect to the valve is accommodated in several ways. First, a loose thread connection is provided at the point of attachment between the valve stem and the diaphragm. Second, the valve poppet has a spherical surface which mates with a frustoconical valve seat. Third, the diaphragm, which has a depending skirt, is free to move across the open end of the valve body prior to clamping the top to the valve body with the diaphragm sandwiched in between.