Pressure regulating systems

摘要

A regulating system for regulating the pressure in a fluid flow line particularly an L.P.G. supply line to the carburation system of an internal combustion engine comprises a regulating device connected in the flow line for varying the fluid flow rate along the line and an electro-fluid control loop comprising a feed-back line connected to the flow line to provide a feed-back pressure related to the pressure in the flow line and a control arrangement in which the feed-back pressure is compared with a reference pressure to provide an electrical output signal for controlling the regulating device in the sense to maintain a predetermined relationship between the feed-back pressure and the reference pressure. The control arrangement has a pair of control chambers, each control chamber being divided into sub-chambers by a flexible diaphragm and the feed-back pressure being connected to act in one sub-chamber and the reference pressure being connected to act in the other sub-chamber. A diaphragm position senser is associated with each control chamber and comprises an electric senser having a senser coil whose electrical output is representative of the distance of the diaphragm from it, the arrangement being such that a variation in the feed-back pressure in relation to the reference pressure causes the diaphragms to move in opposite directions relatively to their associated senser coils. Comparator means are provided for comparing the electrical outputs from the sensor coils to provide an output for controlling said regulating device.