A pressure type flow rate control apparatus is provided wherein flow rate of fluid passing through an orifice is computed as Qc=KP1 (where K is a proportionality constant) or as Qc=KP2.sup.m (P1-P2).sup.n (where K is a proportionality constant, m and n constants) by using orifice upstream side pressure P1 and/or orifice downstream side pressure P2. A fluid passage between the downstream side of a control valve and a fluid supply pipe of the pressure type flow rate control apparatus comprises at least 2 fluid passages in parallel, and orifices having different flow rate characteristics are provided for each of these fluid passages, wherein fluid in a small flow quantity area flows to one orifice for flow control of fluid in the small flow quantity area, while fluid in a large flow quantity area flows to the other orifice for flow control of fluid in the large flow quantity area.

A variable flow rate gas control valve for use in consumer and commercial appliances is presented. The valve utilizes two or more solenoids to control the operating position of two different valve members whose orifices are sized in an exponential relationship with one another. By opening one or more of the valving members in various combinations, a variable flow rate of gaseous fuel may be controlled in integer multiple steps from full off to full on. The solenoid configurations may be in line, opposing, or symmetrical about an axis of the valve. The number of unique flow rates (F) is related to the number of solenoids (N) as F=2.sup.N. The relationship between the size (S) of the individual gas control orifices for each of the solenoids is related to N by the relationship S=2.sup.n1 for each individual gas control orifice (n) numbered 1 to N.