Automatic mechanism operated by a pre-set pressure

Claim 1

AN AUTOMATIC MECHANISM FOR OPERATION BY A PREDETERMINED PRESSURE VARIATION, COMPRISING A SOURCE OF FLUID PRESSURE TAKEN FROM THE CIRCUITTO BE CONTROLLED, VALVE MEANS ASSOCIATED WITH SAID CIRCUIT, A RESERVOIR OF PREDETERMINED VOLUME COUPLED WITH SAID SOURCE OF FLUID PRESSURE, A POROUS BARRIER BETWEEN SAID SOURCE OF FLUID PRESSURE AND SAID RESERVOIRC, A DIFFERENTIAL PRESSURE VALVE HAVING TWO CHAMBERS WITH A FLEXIBLE DIAPHRAGM FORMING A COMMON WALL, A FIRST OF SAID CHAMBERS BEING CONNECTED TO THE FLUID PRESSURE SOURCE AND THE SECOND OF SAID CHAMBERS BEING CONNECTED TO SAID RESERVOIR, VALVE MEANS CONNECTING THE SECOND OF SAID CHAMBERS TO A FLUID PRESSURE OPERABLE RELAY ASSEMBLY AND INCLUDING A MOVABLE VALVE MEMBER SPRING-LOADED INTO CLOSING POSITION AND COUPLED TO THE DIAPHRAGM, SID RELAY ASSEMBLY INCLUDING A FLUIDOPERATED CYLINDER AND PISTON DEVICE ARRANGED TO CAUSE ACTUATION OF SAID VLAVE MEANS ARRANGED TO RELIEVE PRESSURE IN SAID CIRCUIT TO BE CONTROLLED, HEREBY A PRESSURE DROP IN SAID CIRCUIT CAUSES THE GREATER PRESSURE THEN PREVALENT IN THE RESERVOIR TO OPEN THE SPRING-LOADED VALVE IN SAID SECOND CHAMBER WHEREAFTER SAID GREATER PRESSURE IS TRANSMITTED TO SAID RELAY ASSEMBLY TO CAUSE ACTUATION OF THE VALVE MEANS TO RELIEVE THE PRESSURE THEREIN.